49 CFR 192.939 - What are the required reassessment intervals?

Code of Federal Regulations, 2011 CFR

2011-10-01

... Transmission Pipeline Integrity Management § 192.939 What are the required reassessment intervals? An operator... stress levels of pipeline (operating at or above 30% SMYS) listed in ASME/ANSI B31.8S, section 5, Table 3... equivalent technology following the requirements in paragraph (a)(1) of this section except that the stress...

49 CFR 192.939 - What are the required reassessment intervals?

Code of Federal Regulations, 2012 CFR

2012-10-01

... Transmission Pipeline Integrity Management § 192.939 What are the required reassessment intervals? An operator... stress levels of pipeline (operating at or above 30% SMYS) listed in ASME/ANSI B31.8S, section 5, Table 3... equivalent technology following the requirements in paragraph (a)(1) of this section except that the stress...

49 CFR 192.939 - What are the required reassessment intervals?

Code of Federal Regulations, 2014 CFR

2014-10-01

... Transmission Pipeline Integrity Management § 192.939 What are the required reassessment intervals? An operator... stress levels of pipeline (operating at or above 30% SMYS) listed in ASME/ANSI B31.8S, section 5, Table 3... equivalent technology following the requirements in paragraph (a)(1) of this section except that the stress...

Assessing surgeon stress when operating using heart rate variability and the State Trait Anxiety Inventory: will surgery be the death of us?

PubMed

Jones, K I; Amawi, F; Bhalla, A; Peacock, O; Williams, J P; Lund, J N

2015-04-01

Performance in the operating room is affected by a combination of individual, patient and environmental factors amongst others. Stress has a potential negative impact on performance with the quality of surgical practice and patient safety being affected as a result. In order to appreciate the level of stress encountered during surgical procedures both objective and subjective methods can be used. This study reports the use of a combined objective (physiological) and subjective (psychological) method for evaluating stress experienced by the operating surgeon. Six consultant colorectal surgeons were evaluated performing eighteen anterior resections. Heart rate was recorded using a wireless chest strap at eight pre-determined operative steps. Heart Rate Variability indices were calculated offline using computerized software. Surgeon reported stress was collected using the State Trait Anxiety Inventory, a validated clinical stress scale. A significant increase in stress was demonstrated in all surgeons whilst operating as indicated by sympathetic tone (control: 4.02 ± 2.28 vs operative: 11.42 ± 4.63; P < 0.0001). Peaks in stress according to operative step were comparable across procedures and surgeons. There was a significant positive correlation with subjective reporting of stress across procedures (r = 0.766; P = 0.0005). This study demonstrates a significant increase in sympathetic tone in consultant surgeons measured using heart rate variability during elective colorectal resections. A significant correlation can be demonstrated between HRV measurements and perceived stress using the State Trait Anxiety Inventory. A combined approach to assessing operative stress is required to evaluate any effect on performance and outcomes. Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.

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

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

Mumaw, R.J.

1994-08-01

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

Psychophysiological monitoring of operator's emotional stress in aviation and astronautics.

PubMed

Simonov, P V; Frolov, M V; Ivanov, E A

1980-01-01

The level of emotional stress depending on the power of motivation and the estimation by the subject of the probability (possibility) of goal achievement, largely influences the operator's skill performance (that of a pilot, controller, astronaut). A decrease in the emotional tonus leads to drowsiness, lack of vigilance, missing of significant signals, and to slower reactions. The extremely high stress level disorganizes the activity, complicates it with a trend toward untimely acts and reactions to the insignificant signals (false alarms). The best methods to monitor the degree of the operator's emotional state during his skill performance are the integral estimation of the changes in heart-rate and T-peak amplitude, as well as the analysis of spectral and intonational characteristics of the human voice during radio conversation. These methods were tested on paratroopers, pilots in civil aviation, and airport controllers.

Stress in School Administration: Coping Tips for Principals

ERIC Educational Resources Information Center

Sogunro, Olusegun Agboola

2012-01-01

With the need for rapid school reform amid changes in socioeconomic and political situations, evidence abounds that today's school principals operate in a stress-strained environment. Participants of this study identified at least a form of stress on the job. More than 96% claimed to have experienced work-related stress at a level they believed…

75 FR 14379 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) Models Tay 620-15, Tay 650-15...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-25

...: Following a review of operational data of the Tay 651-54 engine, it has been found that the actual stress... found that the actual stress levels in the Tay 651-54 engine High Pressure Compressor (HPC) stages 1, 3... actual stress levels in the Tay 651-54 engine High Pressure Compressor (HPC) stages 1, 3, 6, 7 and 12...

Acute psychophysiological stress impairs human associative learning.

PubMed

Ehlers, M R; Todd, R M

2017-11-01

Addiction is increasingly discussed asa disorder of associative learning processes, with both operant and classical conditioning contributing to the development of maladaptive habits. Stress has long been known to promote drug taking and relapse and has further been shown to shift behavior from goal-directed actions towards more habitual ones. However, it remains to be investigated how acute stress may influence simple associative learning processes that occur before a habit can be established. In the present study, healthy young adults were exposed to either acute stress or a control condition half an hour before performing simple classical and operant conditioning tasks. Psychophysiological measures confirmed successful stress induction. Results of the operant conditioning task revealed reduced instrumental responding under delayed acute stress that resembled behavioral responses to lower levels of reward. The classical conditioning experiment revealed successful conditioning in both experimental groups; however, explicit knowledge of conditioning as indicated by stimulus ratings differentiated the stress and control groups. These findings suggest that operant and classical conditioning are differentially influenced by the delayed effects of acute stress with important implications for the understanding of how new habitual behaviors are initially established. Copyright © 2017 Elsevier Inc. All rights reserved.

Mathematical Modeling in Systems for Operational Evaluation of the Stress-Strain State of the Arch-Gravity Dam at the Sayano-Shushenskaya Hydroelectric Power Plant

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

Bellendir, E. N.; Gordon, L. A., E-mail: lev-gordon@mail.ru; Khrapkov, A. A.

Current studies of the stress-strain state of the dam at the Sayano-Shushenskaya Hydroelectric Power Plant at VNIIG based on mathematical modeling including full scale and experimental data are described. Applications and programs intended for automatic operational evaluation of the stress-strain state of the dam for optimizing control of the upper race level in the course of the annual filling-drawdown cycle and during seismic events are examined. Improvements in systems for monitoring the stress-strain state of concrete dams are proposed.

Symptoms of psychological distress and post-traumatic stress disorder in United States Air Force "drone" operators.

PubMed

Chappelle, Wayne L; McDonald, Kent D; Prince, Lillian; Goodman, Tanya; Ray-Sannerud, Bobbie N; Thompson, William

2014-08-01

The goal of this study is to repeat a survey administered in 2010 to assess for changes in mental health among United States Air Force aircrew operating Predator/Reaper remotely piloted aircraft, also commonly referred to as "drones." Participants were assessed for self-reported sources of occupational stress, levels of clinical distress using the Outcome Questionnaire-45.2, and symptoms of post-traumatic stress disorder (PTSD) using the PTSD Checklist-Military Version. A total of 1,094 aircrew responded to the web-based survey composed of the commercially available standardized instruments mentioned above. The survey also contained nonstandardized items asking participants to report the main sources of their occupational stress, as well as questions addressing demographics and work-related characteristics. The estimated response rate to the survey was 49%. Study results reveal the most problematic self-reported stressors are operational: low manning, extra duties/administrative tasks, rotating shift work, and long hours. The results also reveal 10.72% of operators self-reported experiencing high levels of distress and 1.57% reported high levels of PTSD symptomology. The results are lower than findings from the 2010 survey and from soldiers returning from Iraq and Afghanistan. Implications of the study and recommendations for United States Air Force line leadership and mental health providers are discussed. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

Reassessment of psychological distress and post-traumatic stress disorder in United States Air Force Distributed Common Ground System operators.

PubMed

Prince, Lillian; Chappelle, Wayne L; McDonald, Kent D; Goodman, Tanya; Cowper, Sara; Thompson, William

2015-03-01

The goal of this study was to assess for the main sources of occupational stress, as well as self-reported symptoms of distress and post-traumatic stress disorder among U.S. Air Force (USAF) Distributed Common Ground System (DCGS) intelligence exploitation and support personnel. DCGS intelligence operators (n=1091) and nonintelligence personnel (n = 447) assigned to a USAF Intelligence, Surveillance, and Reconnaissance Wing responded to the web-based survey. The overall survey response rate was 31%. Study results revealed the most problematic stressors among DCGS intelligence personnel included high workload, low manning, as well as organizational leadership and shift work issues. Results also revealed 14.35% of DCGS intelligence operators' self-reported high levels of psychological distress (twice the rate of DCGS nonintelligence support personnel). Furthermore, 2.0% to 2.5% self-reported high levels of post-traumatic stress disorder symptoms, with no significant difference between groups. The implications of these findings are discussed along with recommendations for USAF medical and mental health providers, as well as operational leadership. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

Biofeedback Training in Crisis Managers: A Randomized Controlled Trial.

PubMed

Janka, A; Adler, C; Brunner, B; Oppenrieder, S; Duschek, S

2017-06-01

Working in crisis environments represents a major challenge, especially for executive personnel engaged in directing disaster operations, i.e. crisis managers. Crisis management involves operating under conditions of extreme stress resulting, for instance, from high-level decision-making, principal responsibility for personnel, multitasking or working under conditions of risk and time pressure. The present study aimed to investigate the efficacy of a newly developed biofeedback training procedure based on electrodermal activity, especially designed for the target group of crisis managers. The training comprised exercises promoting acquisition of control over sympathetic arousal under resting conditions and during exposure to visual, acoustic and cognitive stressors resembling situations related to crisis management. In a randomized controlled design, 36 crisis managers were assigned to either a biofeedback training group or waiting list control group. Subjective stress was assessed using the Perceived Stress Scale. In the training group, stress level markedly decreased; the decrease remained stable at follow-up 2 months after the training. The results indicate that biofeedback training in crisis management is an effective method for stress management that may help to reduce vulnerability to stress-related performance decline and stress-related disease.

Changes in the performance characteristics of a GaAs near infrared light emitting diode when exposed to various current and thermal stresses

NASA Technical Reports Server (NTRS)

Thomas, E. F., Jr.

1974-01-01

The changes that occurred in the optical and electrical characteristics of a near infrared, GaAs light emitting diode, when operated under various levels and combinations of current and thermal stresses are discussed. A total of forty parts were operated for two thousand hours under eight different sets of dc current and ambient temperature conditions. Degradation in the radiant optical power of these devices was thirty-four percent when operated at their rated current and an ambient temperature of 298K (25 C). Derating the current and/or the thermal stress reduced the degradation of this parameter in approximately a linear manner. All degraded devices behaved similarly, exhibiting rapid nonlinear degradation followed by a gradual linear degradation and finally a period of stable operation. An attempt was made to correlate initial device condition to degradation during stress testing, but met with little success.

Brace and deformity-related stress level in females with adolescent idiopathic scoliosis based on the Bad Sobernheim Stress Questionnaires

PubMed Central

Misterska, Ewa; Glowacki, Maciej; Harasymczuk, Jerzy

2011-01-01

Summary Background Psychopathological symptoms occur more often in chronically ill patients than in healthy populations. The aim of this study was to analyze the associations between different types of treatment and stress levels. Material/Methods The study group consisted of 69 females, of whom 35 were treated conservatively with a Cheneau brace; the other 34 subjects were treated operatively and, after correction of scoliosis with thoracoplasty, wore a brace for 12 weeks during the postoperative period. Patients completed the Polish versions of the Bad Sobernheim Stress Questionnaire-Deformity and the Bad Sobernheim Stress Questionnaire-Brace. Results Patients who were treated surgically felt a moderate level of stress connected with wearing the brace and with body deformation. The group treated conservatively felt moderate stress connected with wearing the brace, but a low level of stress in relation to body deformation. The groups differed significantly statistically in the level of stress felt regarding body deformation (p=0.004). In the group treated conservatively, the correlation between the level of stress, the age at which treatment was initiated, and degree of apical translation proved to be significant. Conclusions Patients treated surgically in comparison with patients treated conservatively report higher stress levels connected with body deformation. A higher level of stress depends on the degree of trunk deformation on the frontal plane; stress is also higher in patients who begin conservative treatment at a later age. PMID:21278693

Short-term pre- and post-operative stress prolongs incision-induced pain hypersensitivity without changing basal pain perception.

PubMed

Cao, Jing; Wang, Po-Kai; Tiwari, Vinod; Liang, Lingli; Lutz, Brianna Marie; Shieh, Kun-Ruey; Zang, Wei-Dong; Kaufman, Andrew G; Bekker, Alex; Gao, Xiao-Qun; Tao, Yuan-Xiang

2015-12-02

Chronic stress has been reported to increase basal pain sensitivity and/or exacerbate existing persistent pain. However, most surgical patients have normal physiological and psychological health status such as normal pain perception before surgery although they do experience short-term stress during pre- and post-operative periods. Whether or not this short-term stress affects persistent postsurgical pain is unclear. In this study, we showed that pre- or post-surgical exposure to immobilization 6 h daily for three consecutive days did not change basal responses to mechanical, thermal, or cold stimuli or peak levels of incision-induced hypersensitivity to these stimuli; however, immobilization did prolong the duration of incision-induced hypersensitivity in both male and female rats. These phenomena were also observed in post-surgical exposure to forced swimming 25 min daily for 3 consecutive days. Short-term stress induced by immobilization was demonstrated by an elevation in the level of serum corticosterone, an increase in swim immobility, and a decrease in sucrose consumption. Blocking this short-term stress via intrathecal administration of a selective glucocorticoid receptor antagonist, RU38486, or bilateral adrenalectomy significantly attenuated the prolongation of incision-induced hypersensitivity to mechanical, thermal, and cold stimuli. Our results indicate that short-term stress during the pre- or post-operative period delays postoperative pain recovery although it does not affect basal pain perception. Prevention of short-term stress may facilitate patients' recovery from postoperative pain.

Comparison of different hip prosthesis shapes considering micro-level bone remodeling and stress-shielding criteria using three-dimensional design space topology optimization.

PubMed

Boyle, Christopher; Kim, Il Yong

2011-06-03

Since the late 1980s, computational analysis of total hip arthroplasty (THA) prosthesis components has been completed using macro-level bone remodeling algorithms. The utilization of macro-sized elements requires apparent bone densities to predict cancellous bone strength, thereby, preventing visualization and analysis of realistic trabecular architecture. In this study, we utilized a recently developed structural optimization algorithm, design space optimization (DSO), to perform a micro-level three-dimensional finite element bone remodeling simulation on the human proximal femur pre- and post-THA. The computational simulation facilitated direct performance comparison between two commercially available prosthetic implant stems from Zimmer Inc.: the Alloclassic and the Mayo conservative. The novel micro-level approach allowed the unique ability to visualize the trabecular bone adaption post-operation and to quantify the changes in bone mineral content by region. Stress-shielding and strain energy distribution were also quantified for the immediate post-operation and the stably fixated, post-remodeling conditions. Stress-shielding was highest in the proximal region and remained unchanged post-remodeling; conversely, the mid and distal portions show large increases in stress, suggesting a distal shift in the loadpath. The Mayo design conserves bone mass, while simultaneously reducing the incidence of stress-shielding compared to the Alloclassic, revealing a key benefit of the distinctive geometry. Several important factors for stable fixation, determined in clinical evaluations from the literature, were evident in both designs: high levels of proximal bone loss and distal bone densification. The results suggest this novel computational framework can be utilized for comparative hip prosthesis shape, uniquely considering the post-operation bone remodeling as a design criterion. Copyright © 2011 Elsevier Ltd. All rights reserved.

Three-dimensional computer-aided human factors engineering analysis of a grafting robot.

PubMed

Chiu, Y C; Chen, S; Wu, G J; Lin, Y H

2012-07-01

The objective of this research was to conduct a human factors engineering analysis of a grafting robot design using computer-aided 3D simulation technology. A prototype tubing-type grafting robot for fruits and vegetables was the subject of a series of case studies. To facilitate the incorporation of human models into the operating environment of the grafting robot, I-DEAS graphic software was applied to establish individual models of the grafting robot in line with Jack ergonomic analysis. Six human models (95th percentile, 50th percentile, and 5th percentile by height for both males and females) were employed to simulate the operating conditions and working postures in a real operating environment. The lower back and upper limb stresses of the operators were analyzed using the lower back analysis (LBA) and rapid upper limb assessment (RULA) functions in Jack. The experimental results showed that if a leg space is introduced under the robot, the operator can sit closer to the robot, which reduces the operator's level of lower back and upper limbs stress. The proper environmental layout for Taiwanese operators for minimum levels of lower back and upper limb stress are to set the grafting operation at 23.2 cm away from the operator at a height of 85 cm and with 45 cm between the rootstock and scion units.

Protective Effects of Tualang Honey against Oxidative Stress and Anxiety-Like Behaviour in Stressed Ovariectomized Rats

PubMed Central

Al-Rahbi, Badriya; Zakaria, Rahimah; Othman, Zahiruddin; Hassan, Asma'; Ahmad, Asma Hayati

2014-01-01

The present study aims to evaluate the antioxidant and anxiolytic-like effect of Tualang honey in stressed ovariectomized (OVX) rats. The animals were divided into; (i) nonstressed sham-operated control rats, (ii) sham-operated control rats exposed to stress, (iii) nonstressed OVX rats, (iv) OVX rats exposed to stress, (v) OVX rats exposed to stress and treated with 17 β-oestradiol (E2) (20 μg daily, sc), and (vi) OVX rats exposed to stress and treated with Tualang honey (0.2 g/kg body weight, orally). The open field test was used to evaluate the anxiety-like behaviour and ELISA kits were used to measure oxidant/antioxidant status of the brain homogenates. The result showed that anxiety-like behavior was significantly increased in stressed OVX compared to other groups, and administering either E2 or Tualang honey significantly decreased anxiety-like behaviour in stressed OVX rats. The levels of malondialdehyde (MDA) and protein carbonyl (PCO) were significantly decreased while the levels/activities of superoxide dismutase (SOD), glutathione S-transferases (GST), glutathione peroxidase (GPx), and glutathione reductase (GR) were significantly increased in the brain homogenates of treated stressed OVX groups compared to untreated stressed OVX. In conclusion, Tualang honey has protective effects against brain oxidative stress and may be useful alternative anxiolytic agent especially for postmenopausal women. PMID:27379299

The effects of acceleration stress on human workload and manual control

NASA Technical Reports Server (NTRS)

Gill, R. T.; Albery, W. B.; Ward, S. L.

1986-01-01

The effects of +Gz stress on operator task performance and workload were assessed. Subjects were presented a two dimensional maze and were required to solve it as rapidly as possible (by moving a light dot through it via a trim switch on a control stick) while under G-stress at levels from +1 Gz to +6 Gz. The G-stress was provided by a human centrifuge. The effects of this stress were assessed by two techniques; (1) objective performance measures on the primary maze-solving task, and (2) subjective workload measures obtained using the subjective workload assessment technique (SWAT). It was found that while neither moderate (+3 Gz) nor high (+5 Gz and +6 Gz) levels of G-stress affected maze solving performance, the high G levels did increase significantly the subjective workload of the maze task.

Technological disasters, crisis management and leadership stress.

PubMed

Weisaeth, Lars; Knudsen, Øistein; Tønnessen, Arnfinn

2002-07-01

This paper discusses how psychological stress disturbs decision making during technological crisis and disaster, and how to prevent this from happening. This is exemplified by scientific studies of a Norwegian large scale accident involving hazardous material, and of handling the far-off effects of the nuclear disaster at Chernobyl. The former constitutes an operative level of crisis management, whereas the latter involves crisis management at the strategic and political level. We conclude that stress had a negative effect on decision making in both cases.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A) METOP Stress Analysis Report (Qual Level Random Vibration) A1 Module

NASA Technical Reports Server (NTRS)

Mehitretter, R.

1996-01-01

Stress analysis of the primary structure of the Meteorological Satellites Project (METSAT) Advanced Microwave Sounding Units-A, A1 Module performed using the Meteorological Operational (METOP) Qualification Level 9.66 grms Random Vibration PSD Spectrum is presented. The random vibration structural margins of safety and natural frequency predictions are summarized.

Physiological Indices of Stress Prior to and Following Total Knee Arthroplasty Predict the Occurrence of Severe Post-Operative Pain.

PubMed

Cremeans-Smith, Julie K; Greene, Kenneth; Delahanty, Douglas L

2016-05-01

The severe pain and disability associated with osteoarthritis often motivate individuals to undergo arthroplastic surgery. However, a significant number of surgical patients continue to experience pain following surgery. Prior research has implicated both the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) in the sensitization of pain receptors and chronic pain conditions. This study uses a prospective, observational, cohort design to examine whether physiological stress responses before and after surgery could predict post-operative pain severity. Participants included 110 patients undergoing total knee arthroplasty. Physiological indices of stress included the measurement of catecholamine and cortisol levels in 15-hour urine samples collected prior to and 1 month following surgery, as well as in-hospital heart rate and blood pressure (before and after surgery), which were abstracted from medical records. Patients completed the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) [Bellamy et al., J Orthop Rheumatol 1: , 95 (1988)] 2.5 weeks prior to surgery and at a 3-month follow-up. Contrary to expectations, lower stress hormone levels at baseline were related to more severe post-operative pain. Data at later time points, however, supported our hypothesis: cardiovascular tone shortly before surgery and urinary levels of epinephrine 1 month following surgery were positively related to pain severity 3 months later. Results suggest that the occurrence of post-operative pain can be predicted on the basis of stress physiology prior to and following arthroplastic surgery. © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The contribution of personal and seniority variables to the presence of stress symptoms among Israeli UAV operators.

PubMed

Gal, Shiri; Shelef, Leah; Oz, Idit; Yavnai, Nirit; Carmon, Erez; Gordon, Shirley

2016-01-01

The exposure to war scenes via screens, despite offering a degree of detachment, can be stressful for the operator. The aim of the current study is to examine the existence of anxiety, depression, and post traumatic stress disorder (PTSD) symptoms among unmanned aerial vehicle (UAV) Israeli operators. Participants comprised 41 UAV operators (87.2% male), aged 22-38 ( M age  = 26.05, SD  = 3.54). Most (78.0%) reported having viewed battlefield scenes. All participants completed a total of five questionnaires: Beck Depression Inventory, State-Trait Anxiety Inventory, and three questionnaires of PTSD: Post Trauma Questionnaire (CAPS), the Post-Traumatic Cognition Inventory (CTPI), and the Post-Traumatic Symptom Scale (PSS). Mean scores of depression and anxiety were found significantly lower than diagnosis cut-off points ( p  < .001). Senior operators showed higher means for depression (5.69 vs. 2.58, p  = .040), of stress level (PSS; 3.17 vs. 0.25, p  = .020) and for distress intensity (3.79 vs. 0.57, p  = 0.041) than less-experienced operators. Investigating and monitoring the impact of battlefield exposure in UAV operators are highly beneficial for preventing psychopathology.

[Evaluation of work-related stress in call-center workers: application of a methodology].

PubMed

Ansaloni, Gianluca; Cichella, Patrizia; Morelli, Carla; Alberghini, Villiam; Finardi, Elisabetta; Guglielmin, Antonia Maria; Nini, Donatella; Sacenti, Elisabetta; Stagni, Cristina

2014-01-01

Several studies highlighting a correlation between call-center working conditions and psychosocial and ergonomic hazards. The aim of this study is to provide an operating methodology for the risk assessment of work-related stress. The study involved 554 call-centre workers employed in three insurance organizations and a mixed work group (worker, company and public health representative) for the study management was defined. We experimented an objective self-made checklist and then we administered a modified version of the OSI (Occupational Stress Indicator) questionnaire. We obtained complementary information from the two different data collection methods. The findings highlight a low level of perceived stress and health complaints compared with other studies previously carried out mainly in 'outsourcing' call centres: workers don't show stress symptoms without adopting coping strategies. Moreover the study underlines an acceptable level of work satisfaction, although there are low career opportunities. These results are probable due to the low job seniority associated to the high job security--the large majority of respondents, 87%, consisted of permanent workers--and the working time mainly consisted of daily shifts five days a week. Our methodology seems to be able to detect the level of work-related stress with a good degree of coherence. Furthermore the presence of a mixed work group determined a good level of involvement among the workers: 464 out of 554 operators completed and returned the questionnaire, representing a response rate of about 84%.

Understanding and Controlling Sialylation in a CHO Fc-Fusion Process

PubMed Central

Lewis, Amanda M.; Croughan, William D.; Aranibar, Nelly; Lee, Alison G.; Warrack, Bethanne; Abu-Absi, Nicholas R.; Patel, Rutva; Drew, Barry; Borys, Michael C.; Reily, Michael D.; Li, Zheng Jian

2016-01-01

A Chinese hamster ovary (CHO) bioprocess, where the product is a sialylated Fc-fusion protein, was operated at pilot and manufacturing scale and significant variation of sialylation level was observed. In order to more tightly control glycosylation profiles, we sought to identify the cause of variability. Untargeted metabolomics and transcriptomics methods were applied to select samples from the large scale runs. Lower sialylation was correlated with elevated mannose levels, a shift in glucose metabolism, and increased oxidative stress response. Using a 5-L scale model operated with a reduced dissolved oxygen set point, we were able to reproduce the phenotypic profiles observed at manufacturing scale including lower sialylation, higher lactate and lower ammonia levels. Targeted transcriptomics and metabolomics confirmed that reduced oxygen levels resulted in increased mannose levels, a shift towards glycolysis, and increased oxidative stress response similar to the manufacturing scale. Finally, we propose a biological mechanism linking large scale operation and sialylation variation. Oxidative stress results from gas transfer limitations at large scale and the presence of oxygen dead-zones inducing upregulation of glycolysis and mannose biosynthesis, and downregulation of hexosamine biosynthesis and acetyl-CoA formation. The lower flux through the hexosamine pathway and reduced intracellular pools of acetyl-CoA led to reduced formation of N-acetylglucosamine and N-acetylneuraminic acid, both key building blocks of N-glycan structures. This study reports for the first time a link between oxidative stress and mammalian protein sialyation. In this study, process, analytical, metabolomic, and transcriptomic data at manufacturing, pilot, and laboratory scales were taken together to develop a systems level understanding of the process and identify oxygen limitation as the root cause of glycosylation variability. PMID:27310468

[Work stress, common mental disorders and Work Ability Index among call center workers of an Italian company].

PubMed

Conway, Paul Maurice; Campanini, Paolo; Punzi, Silvia; Fichera, Giuseppe Paolo; Camerino, Donatella; Francioli, Laura; Neri, Luca; Costa, Giovanni

2013-01-01

To test three hypotheses in an Italian sample of call center workers: higher levels of perceived work stress are associated with more frequent common mental disorders (GHQ-12) and a lower Work Ability Index; combining the Job Strain (JS) and Effort/Reward Imbalance (ERI) models increases explained variance in health over and above either model when applied separately; compared with outbound operators, inbound call handlers are expected to report a lower health status,which is due to a more intense exposure to task-related work stress factors in the latter. A multi-center cross-sectional study, conducted by means of interviews and self-administered questionnaires. Call handlers working in the Italian branch of a telecommunication multinational company. In all, 1,106 permanent workers were examined (35.9%of the total target population, 98.9% response rate). The majority were women (76.5%);mean age was 33.3 (SD: 3.9) and company seniority 8.0 (SD: 2.1). Nearly 60% worked as inbound call handlers, about one third as outbound operators. Work stress was measured with the well-known JS and ERI models. Three exposure levels (based on tertiles) were identified for each scale. Common mental disorders were measured with the GHQ-12 questionnaire. Subjects with a GHQ-12 score 4 were classified as "cases". The Work Ability Index (WAI) was used to evaluate work ability. Being in the "poor" or "moderate" categories of the WAI indicated a low work ability status. Cronbach's alphas were 0.70 for all scales. Multivariate Poisson regressions showed that both models were linked to more frequent common mental disorders and a lower WAI. Moreover, combined models demonstrated an advantage in terms of explained variance in health. Finally, performing inbound call handling was associated with a lower WAI in comparison with engaging in outbound activities. Mediation analyses showed that such association is explained by the higher levels of psychological job demands and Job Strain experienced by inbound operators. Our results highlight the relevance of work stress as a risk factor for lower psychological health, and especially for a poorer WAI among call center workers. The combined use of the two models increases completeness of work stress assessment in this sector.The higher levels of work stress and the lower WAI observed among inbound operators are due to objectively less favourable task-related characteristics.

Stress studies in EFG

NASA Technical Reports Server (NTRS)

1983-01-01

A computer code which can account for plastic deformation effects on stress generated in silicon sheet grown at high speeds is fully operative. Stress and strain rate distributions are presented for two different sheet temperature profiles. The calculations show that residual stress levels are very sensitive to details of the cooling profile in a sheet with creep. Experimental work has been started in several areas to improve understanding of ribbon temperature profiles and stress distributions associated with a 10 cm wide ribbon cartridge system.

A Novel Stress-Diathesis Model to Predict Risk of Post-operative Delirium: Implications for Intra-operative Management.

PubMed

El-Gabalawy, Renée; Patel, Ronak; Kilborn, Kayla; Blaney, Caitlin; Hoban, Christopher; Ryner, Lawrence; Funk, Duane; Legaspi, Regina; Fisher, Joseph A; Duffin, James; Mikulis, David J; Mutch, W Alan C

2017-01-01

Introduction: Risk assessment for post-operative delirium (POD) is poorly developed. Improved metrics could greatly facilitate peri-operative care as costs associated with POD are staggering. In this preliminary study, we develop a novel stress-diathesis model based on comprehensive pre-operative psychiatric and neuropsychological testing, a blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) carbon dioxide (CO 2 ) stress test, and high fidelity measures of intra-operative parameters that may interact facilitating POD. Methods: The study was approved by the ethics board at the University of Manitoba and registered at clinicaltrials.gov as NCT02126215. Twelve patients were studied. Pre-operative psychiatric symptom measures and neuropsychological testing preceded MRI featuring a BOLD MRI CO 2 stress test whereby BOLD scans were conducted while exposing participants to a rigorously controlled CO 2 stimulus. During surgery the patient had hemodynamics and end-tidal gases downloaded at 0.5 hz. Post-operatively, the presence of POD and POD severity was comprehensively assessed using the Confusion Assessment Measure -Severity (CAM-S) scoring instrument on days 0 (surgery) through post-operative day 5, and patients were followed up at least 1 month post-operatively. Results: Six of 12 patients had no evidence of POD (non-POD). Three patients had POD and 3 had clinically significant confusional states (referred as subthreshold POD; ST-POD) (score ≥ 5/19 on the CAM-S). Average severity for delirium was 1.3 in the non-POD group, 3.2 in ST-POD, and 6.1 in POD (F-statistic = 15.4, p < 0.001). Depressive symptoms, and cognitive measures of semantic fluency and executive functioning/processing speed were significantly associated with POD. Second level analysis revealed an increased inverse BOLD responsiveness to CO 2 pre-operatively in ST-POD and marked increase in the POD groups when compared to the non-POD group. An association was also noted for the patient population to manifest leucoaraiosis as assessed with advanced neuroimaging techniques. Results provide preliminary support for the interacting of diatheses (vulnerabilities) and intra-operative stressors on the POD phenotype. Conclusions: The stress-diathesis model has the potential to aid in risk assessment for POD. Based on these initial findings, we make some recommendations for intra-operative management for patients at risk of POD.

A Novel Stress-Diathesis Model to Predict Risk of Post-operative Delirium: Implications for Intra-operative Management

PubMed Central

El-Gabalawy, Renée; Patel, Ronak; Kilborn, Kayla; Blaney, Caitlin; Hoban, Christopher; Ryner, Lawrence; Funk, Duane; Legaspi, Regina; Fisher, Joseph A.; Duffin, James; Mikulis, David J.; Mutch, W. Alan C.

2017-01-01

Introduction: Risk assessment for post-operative delirium (POD) is poorly developed. Improved metrics could greatly facilitate peri-operative care as costs associated with POD are staggering. In this preliminary study, we develop a novel stress-diathesis model based on comprehensive pre-operative psychiatric and neuropsychological testing, a blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) carbon dioxide (CO2) stress test, and high fidelity measures of intra-operative parameters that may interact facilitating POD. Methods: The study was approved by the ethics board at the University of Manitoba and registered at clinicaltrials.gov as NCT02126215. Twelve patients were studied. Pre-operative psychiatric symptom measures and neuropsychological testing preceded MRI featuring a BOLD MRI CO2 stress test whereby BOLD scans were conducted while exposing participants to a rigorously controlled CO2 stimulus. During surgery the patient had hemodynamics and end-tidal gases downloaded at 0.5 hz. Post-operatively, the presence of POD and POD severity was comprehensively assessed using the Confusion Assessment Measure –Severity (CAM-S) scoring instrument on days 0 (surgery) through post-operative day 5, and patients were followed up at least 1 month post-operatively. Results: Six of 12 patients had no evidence of POD (non-POD). Three patients had POD and 3 had clinically significant confusional states (referred as subthreshold POD; ST-POD) (score ≥ 5/19 on the CAM-S). Average severity for delirium was 1.3 in the non-POD group, 3.2 in ST-POD, and 6.1 in POD (F-statistic = 15.4, p < 0.001). Depressive symptoms, and cognitive measures of semantic fluency and executive functioning/processing speed were significantly associated with POD. Second level analysis revealed an increased inverse BOLD responsiveness to CO2 pre-operatively in ST-POD and marked increase in the POD groups when compared to the non-POD group. An association was also noted for the patient population to manifest leucoaraiosis as assessed with advanced neuroimaging techniques. Results provide preliminary support for the interacting of diatheses (vulnerabilities) and intra-operative stressors on the POD phenotype. Conclusions: The stress-diathesis model has the potential to aid in risk assessment for POD. Based on these initial findings, we make some recommendations for intra-operative management for patients at risk of POD. PMID:28868035

Levels of Stress among General Practitioners, Students and Specialists In Pediatric Dentistry during Dental Treatment.

PubMed

Davidovich, E; Pessov, Y; Baniel, A; Ram, D

2015-01-01

To assess self-reported stress during the performance of different procedures in pediatric dentistry, according to the professional experience of the dentists. During the years 2010 to 2011, an anonymous survey was administered by means of an internet link, and by distribution at professional meetings of dentists . No statistically significant differences in stress were reported for maxilla and mandibular procedures. Placement of a rubber dam was rated as the most stressful procedure among dental students. For general practitioners and specialists, injection of local anesthesia to an anxious child was the most stressful procedure, regardless of age, sex, or years of professional experience. A negative correlation was found between years of experience and level of stress for all the procedures surveyed, but not for the use of nitrous oxide. No differences were found between male and female dentists in stress scores for any of the procedures. Higher rates of stress during operative procedures were reported among dental students than among experienced dentists. Anxiety of the pediatric patients, but not the location of the procedure: maxillary or mandibular, affected the dentists' reported level of stress.

Heat stress in front and rear cockpits of F-4 aircraft

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

Nunneley, S.A.; Stribley, R.F.; Allan, J.R.

The thermal stresses encountered in the front and rear cockpits of F-4 aircraft flying low-level missions in warm, moderately humid weather and physiological responses to these stresses are investigated. Measurements of ground and cockpit environmental temperatures and subject skin and core temperatures were acquired for the preflight taxi, low-level flight, ordnance delivery and postflight taxi phases of 36 flights of F-4E aircraft performed to simulate low-level ground attack missions. Cockpit dry-bulb temperatures are found to exceed those on the ground during ground operations, and to decrease in flight in the front, but not the rear, cockpit. A linear relationship betweenmore » cockpit dry bulb and temperatures is also found in each of the mission phases, along with increases in skin and core temperatures with cockpit temperatures and sweat rates depending both on cockpit temperatures and the amount of clothing worn. Adverse physiological effects related to nausea and acceleration tolerances are also noted. It is concluded that the cockpit cooling system of the F-4 allows the development of operationally significant heat stress, which may be corrected by better design and testing of the cooling system.« less

Stress levels for well-fitting implant superstructures as a function of tightening force levels, tightening sequence, and different operators.

PubMed

Nissan, J; Gross, M; Shifman, A; Assif, D

2001-07-01

Unfavorable stress distribution and occlusal overload have been reported to result in failures ranging from screw loosening to loss of osseointegration. The purpose of this study was to assess the effect of different tightening forces and sequences, with different operators, on stresses generated on an accurately fitting implant superstructure on multiple working casts made with a splinted impression technique. The effects of different tightening forces (10 and 20 Ncm) were assessed with the use of 30 stone casts made from a metal master model with a splinted impression technique. Stresses generated were recorded by 4 strain gauges attached to the superior surface of the master framework. A multiple analysis of variance with repeated measures was performed to test for significant differences among the groups. Tightening force values at 10 Ncm ranged from 150.43 to 256 Ncm. At 20 Ncm, microstrain values ranged from 149.43 to 284.37 Ncm. Microstrain values related to the sequence of tightening ranged from 150.8 to 308.43 Ncm (left to right) and 154.63 to 274.80 Ncm (right to left). For the different operators, microstrain values ranged from 100.13 to 206.07 Ncm. No statistically significant differences among the variables of tightening force, tightening sequence, and operators were found ( P >.05). The interaction between groups and strain gauges was also found to be nonsignificant (P >.05). The potential of variable tightening force and tightening sequence to generate unfavorable preload stresses can be minimized through use of the splinted impression technique, which ensures an accurately fitting superstructure.

Studies on thermo-elastic heating of horns used in ultrasonic plastic welding.

PubMed

Roopa Rani, M; Prakasan, K; Rudramoorthy, R

2015-01-01

Ultrasonic welding horn is half wavelength section or tool used to focus the ultrasonic vibrations to the components being welded. The horn is designed in such a way that it maximizes the amplitude of the sound wave passing through it. The ends of the horn represent the displacement anti-nodes and the center the 'node' of the wave. As the horns perform 20,000 cycles of expansion and contraction per second, they are highly stressed at the nodes and are heated owing to thermo-elastic effects. Considerable temperature rise may be observed in the horn, at the nodal region when working at high amplitudes indicating high stress levels leading to failure of horns due to cyclic loading. The limits for amplitude must therefore be evaluated for the safe working of the horn. Horns made of different materials have different thermo-elastic behaviors and hence different temperatures at the nodes and antinodes. This temperature field can be used as a control mechanism for setting the amplitude/weld parameters. Safe stress levels can be predicted using modal and harmonic analyses followed by a stress analysis to study the effect of cyclic loads. These are achieved using 'Ansys'. The maximum amplitude level obtained from the stress analysis is used as input for 'Comsol' to predict the temperature field. The actual temperature developed in the horn during operation is measured using infrared camera and compared with the simulated temperature. From experiments, it is observed that horn made of titanium had the lowest temperature rise at the critical region and can be expected to operate at amplitudes up to 77 μm without suffering failure due to cyclic loading. The method of predicting thermo-elastic stresses and temperature may be adopted by the industry for operating the horn within the safe stress limits thereby extending the life of the horn. Copyright © 2014 Elsevier B.V. All rights reserved.

Investigations of Air-cooled Turbine Rotors for Turbojet Engines II : Mechanical Design, Stress Analysis, and Burst Test of Modified J33 Split-disk Rotor / Richard H. Kemp and Merland L. Moseson

NASA Technical Reports Server (NTRS)

Kemp, Richard H; Moseson, Merland L

1952-01-01

A full-scale J33 air-cooled split turbine rotor was designed and spin-pit tested to destruction. Stress analysis and spin-pit results indicated that the rotor in a J33 turbojet engine, however, showed that the rear disk of the rotor operated at temperatures substantially higher than the forward disk. An extension of the stress analysis to include the temperature difference between the two disks indicated that engine modifications are required to permit operation of the two disks at more nearly the same temperature level.

Operation of Wastewater Treatment Plants: A Field Study Training Program. Volume II. Second Edition.

ERIC Educational Resources Information Center

California State Univ., Sacramento. Dept. of Civil Engineering.

This manual was prepared by experienced wastewater collection system workers to provide a home study course to develop new qualified workers and expand the abilities of existing workers. This volume emphasizes material needed by intermediate-level operators and stresses the operation and maintenance of conventional treatment plants. This volume…

[Nitrogen stress measurement of canola based on multi-spectral charged coupled device imaging sensor].

PubMed

Feng, Lei; Fang, Hui; Zhou, Wei-Jun; Huang, Min; He, Yong

2006-09-01

Site-specific variable nitrogen application is one of the major precision crop production management operations. Obtaining sufficient crop nitrogen stress information is essential for achieving effective site-specific nitrogen applications. The present paper describes the development of a multi-spectral nitrogen deficiency sensor, which uses three channels (green, red, near-infrared) of crop images to determine the nitrogen level of canola. This sensor assesses the nitrogen stress by means of estimated SPAD value of the canola based on canola canopy reflectance sensed using three channels (green, red, near-infrared) of the multi-spectral camera. The core of this investigation is the calibration methods between the multi-spectral references and the nitrogen levels in crops measured using a SPAD 502 chlorophyll meter. Based on the results obtained from this study, it can be concluded that a multi-spectral CCD camera can provide sufficient information to perform reasonable SPAD values estimation during field operations.

A status review of photovoltaic power conversion equipment reliability, safety, and quality assurance protocols

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

Hacke, Peter; Lokanath, Sumanth; Williams, Paul

Data indicate that the inverter is the element of the photovoltaic plant that has the highest number of service calls and the greatest operation and maintenance cost burden. This paper describes the projects and relevant background needed in developing design qualification standards that would serve to establish a minimum level of reliability, along with a review of photovoltaic inverter quality and safety standards, most of which are in their infancy. We compare stresses and levels for accelerated testing of inverters proposed in the standard drafts, and those proposed by manufacturers and purchasers of inverters. We also review bases for themore » methods, stress types, and stress levels for durability testing of key inverter components. Many of the test protocols appear to need more comprehensive inclusion of stress factors existing in the natural environment such as wind driven rain, dust, and grid disturbances. Further understanding of how temperature, humidity ingress, and voltage bias affect the inverters and their components is also required. We provide data indicating inconsistent quality of the inverters and the durability of components leading to greater cost for the photovoltaic plant operator. Accordingly, the recommendation for data collection within quality standards for obtaining cost of ownership metrics is made. Design validation testing using realistic operation, environmental, and connection conditions, including under end-use field conditions with feedback for continuous improvement is recommended for inclusion within a quality standard.« less

A status review of photovoltaic power conversion equipment reliability, safety, and quality assurance protocols

DOE PAGES

Hacke, Peter; Lokanath, Sumanth; Williams, Paul; ...

2017-10-10

Data indicate that the inverter is the element of the photovoltaic plant that has the highest number of service calls and the greatest operation and maintenance cost burden. This paper describes the projects and relevant background needed in developing design qualification standards that would serve to establish a minimum level of reliability, along with a review of photovoltaic inverter quality and safety standards, most of which are in their infancy. We compare stresses and levels for accelerated testing of inverters proposed in the standard drafts, and those proposed by manufacturers and purchasers of inverters. We also review bases for themore » methods, stress types, and stress levels for durability testing of key inverter components. Many of the test protocols appear to need more comprehensive inclusion of stress factors existing in the natural environment such as wind driven rain, dust, and grid disturbances. Further understanding of how temperature, humidity ingress, and voltage bias affect the inverters and their components is also required. We provide data indicating inconsistent quality of the inverters and the durability of components leading to greater cost for the photovoltaic plant operator. Accordingly, the recommendation for data collection within quality standards for obtaining cost of ownership metrics is made. Design validation testing using realistic operation, environmental, and connection conditions, including under end-use field conditions with feedback for continuous improvement is recommended for inclusion within a quality standard.« less

[The role of oxidative stress and arterial blood supply in the transplanted liver function].

PubMed

Kóbori, László; Sárváry, Enikö; Nemes, Balázs; Lakatos, Márta; Fehérvári, Imre; Görög, Dénes; Dallos, Gábor; Gerlei, Zsuzsa; Fazakas, János; Tóth, Tibor; Lengyel, Gabriella; Fehér, János; Járay, Jenö

2003-11-09

Reperfusion injury and hepatic artery thrombosis are major causes of graft failure after liver transplantation. The magnitude of oxidative stress increases after reperfusion and the appearance of an arterial thrombosis presents a higher risk for the graft and patient survival. The aim of the study was to detect the level of oxidative stress in the perioperative period of transplantation. Clinical documentations of 32 patients were investigated and the level of myeloperoxidase (MPO) was measured for the monitoring of the oxidative stress. The mean age of the patients was 43 years and hepatitis C cirrhosis was the most common indication (14 cases, 43%). Two retransplantations were done. In 24 cases (75%) the primary graft functions and patient survival were good. Eight patients died, in two cases because of acute liver failure, in two cases due to primary non function and in four cases due to late complications. The incidence of hepatic artery thrombosis was 11% (4 cases) and the incidence of acute rejection was 35% (12 cases). The level of MPO was higher (65 ng/ml) in all patients before operation. After the first 48 hours this level increased significantly (p < 0.0001) up to the mean level of 123 ng/ml and decreased after one week. In the cases with acute liver failure and hepatic artery thrombosis high levels of MPO were measured. This study provides evidence of increased oxidative stress before liver transplantation. The magnitude of these changes increased after operation, mostly in cases with acute liver failure and hepatic artery thrombosis. Reducing the reperfusion injury and performing an "ideal" arterial supply for the liver-graft present better survival.

Organizational Stress Moderates the Relationship between Mental Health Provider Adaptability and Organizational Commitment

PubMed Central

Green, Amy E.; Dishop, Christopher; Aarons, Gregory A

2016-01-01

Objective Community mental health providers often operate within stressful work environments and are at high risk for emotional exhaustion, which can negatively affect job performance and client satisfaction with services. This cross-sectional study examines the relationships between organizational stress, provider adaptability, and organizational commitment. Methods Variables were analyzed using moderated multi-level regression in a sample of 311 mental health providers from 49 community mental health programs. Results Stressful organizational climate, characterized by high levels of emotional exhaustion, role conflict, and role overload, was negatively related to organizational commitment. Organizational stress moderated the relationship between provider adaptability and organizational commitment, such that those who were more adaptable had greater levels of organizational commitment when organizational stress was low, but were less committed than those who were less adaptable when organizational stress was high. Conclusions In the current study, providers higher in adaptability may perceive their organization as a greater fit when characterized by lower levels of stressfulness; however, highly adaptable providers may also exercise choice that manifests in lower commitment to staying in an overly stressful work environment. Service systems and organizational contexts are becoming increasingly demanding and stressful for direct mental health service providers. Therefore, community mental health organizations should assess and understand their organizational climate and intervene with empirically based organizational strategies when necessary to reduce stressful climates and maintain desirable employees. PMID:27301760

Resource Optimization Techniques and Security Levels for Wireless Sensor Networks Based on the ARSy Framework.

PubMed

Parenreng, Jumadi Mabe; Kitagawa, Akio

2018-05-17

Wireless Sensor Networks (WSNs) with limited battery, central processing units (CPUs), and memory resources are a widely implemented technology for early warning detection systems. The main advantage of WSNs is their ability to be deployed in areas that are difficult to access by humans. In such areas, regular maintenance may be impossible; therefore, WSN devices must utilize their limited resources to operate for as long as possible, but longer operations require maintenance. One method of maintenance is to apply a resource adaptation policy when a system reaches a critical threshold. This study discusses the application of a security level adaptation model, such as an ARSy Framework, for using resources more efficiently. A single node comprising a Raspberry Pi 3 Model B and a DS18B20 temperature sensor were tested in a laboratory under normal and stressful conditions. The result shows that under normal conditions, the system operates approximately three times longer than under stressful conditions. Maintaining the stability of the resources also enables the security level of a network's data output to stay at a high or medium level.

Resource Optimization Techniques and Security Levels for Wireless Sensor Networks Based on the ARSy Framework

PubMed Central

Kitagawa, Akio

2018-01-01

Wireless Sensor Networks (WSNs) with limited battery, central processing units (CPUs), and memory resources are a widely implemented technology for early warning detection systems. The main advantage of WSNs is their ability to be deployed in areas that are difficult to access by humans. In such areas, regular maintenance may be impossible; therefore, WSN devices must utilize their limited resources to operate for as long as possible, but longer operations require maintenance. One method of maintenance is to apply a resource adaptation policy when a system reaches a critical threshold. This study discusses the application of a security level adaptation model, such as an ARSy Framework, for using resources more efficiently. A single node comprising a Raspberry Pi 3 Model B and a DS18B20 temperature sensor were tested in a laboratory under normal and stressful conditions. The result shows that under normal conditions, the system operates approximately three times longer than under stressful conditions. Maintaining the stability of the resources also enables the security level of a network’s data output to stay at a high or medium level. PMID:29772773

The operator's emotional stability

NASA Technical Reports Server (NTRS)

Zilberman, P. B.

1975-01-01

An attempt is made to provide a psychological interpretation of the concept of emotional stability in connection with other psychics qualities of an operator's personality. Emotional stability is understood as a person's capacity to control his emotional state for the purpose of maintaining the necessary level of work performance under extreme stress conditions. By modeling the operator's sensorimotor activity and by comparing the productivity indicators under ordinary conditions with those obtained during work involving an emotional load, the level of emotional stability can be determined.

Three-year aging of prototype flight laser at 10 kHz and 1 ns pulses with external frequency doubler for ICESat-2 mission

NASA Astrophysics Data System (ADS)

Konoplev, Oleg A.; Chiragh, Furqan L.; Vasilyev, Aleksey A.; Edwards, Ryan; Stephen, Mark A.; Troupaki, Elisavet; Yu, Anthony W.; Krainak, Michael A.; Sawruk, Nick; Hovis, Floyd; Culpepper, Charles F.; Strickler, Kathy

2016-05-01

We present the results of a three-year operational-aging test of a specially designed prototype flight laser operating at 1064 nm, 10 kHz, 1ns, 15W average power and externally frequency-doubled. Fibertek designed and built the q-switched, 1064nm laser and this laser was in a sealed container of dry air pressurized to 1.3 atm. The external frequency doubler was in a clean room at a normal air pressure. The goal of the experiment was to measure degradation modes at 1064 and 532 nm separately. The external frequency doubler consisted of a Lithium triborate, LiB3O5, non-critically phase-matched crystal. After some 1064 nm light was diverted for diagnostics, 13.7W of fundamental power was available to pump the doubling crystal. Between 8.5W and 10W of 532nm power was generated, depending on the level of stress and degradation. The test consisted of two stages, the first at 0.3 J/cm2 for almost 1 year, corresponding to expected operational conditions, and the second at 0.93 J/cm2 for the remainder of the experiment, corresponding to accelerated optical stress testing. We observed no degradation at the first stress-level and linear degradation at the second stress-level. The linear degradation was linked to doubler crystal output surface changes from laser-assisted contamination. We estimate the expected lifetime for the flight laser at 532 nm using fluence as the stress parameter. This work was done for NASA's Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) LIDAR at Goddard Space Flight Center in Greenbelt, MD with the goal of 1 trillion shots lifetime.

33 CFR 106.235 - Maritime Security (MARSEC) Level coordination and implementation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... in compliance with the security requirements in this part for the MARSEC Level in effect for the OCS..., and stress the need for increased vigilance. (d) An OCS facility owner or operator whose facility is...

Designing automation for complex work environments under different levels of stress.

PubMed

Sauer, Juergen; Nickel, Peter; Wastell, David

2013-01-01

This article examines the effectiveness of different forms of static and adaptable automation under low- and high-stress conditions. Forty participants were randomly assigned to one of four experimental conditions, comparing three levels of static automation (low, medium and high) and one level of adaptable automation, with the environmental stressor (noise) being varied as a within-subjects variable. Participants were trained for 4 h on a simulation of a process control environment, called AutoCAMS, followed by a 2.5-h testing session. Measures of performance, psychophysiology and subjective reactions were taken. The results showed that operators preferred higher levels of automation under noise than under quiet conditions. A number of parameters indicated negative effects of noise exposure, such as performance impairments, physiological stress reactions and higher mental workload. It also emerged that adaptable automation provided advantages over low and intermediate static automation, with regard to mental workload, effort expenditure and diagnostic performance. The article concludes that for the design of automation a wider range of operational scenarios reflecting adverse as well as ideal working conditions needs to be considered. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

The effect of concentrated bone marrow aspirate in operative treatment of fifth metatarsal stress fractures; a double-blind randomized controlled trial.

PubMed

Weel, Hanneke; Mallee, Wouter H; van Dijk, C Niek; Blankevoort, Leendert; Goedegebuure, Simon; Goslings, J Carel; Kennedy, John G; Kerkhoffs, Gino M M J

2015-08-20

Fifth metatarsal (MT-V) stress fractures often exhibit delayed union and are high-risk fractures for non-union. Surgical treatment, currently considered as the gold standard, does not give optimal results, with a mean time to fracture union of 12-18 weeks. In recent studies, the use of bone marrow cells has been introduced to accelerate healing of fractures with union problems. The aim of this randomized trial is to determine if operative treatment of MT-V stress fractures with use of concentrated blood and bone marrow aspirate (cB + cBMA) is more effective than surgery alone. We hypothesize that using cB + cBMA in the operative treatment of MT-V stress fractures will lead to an earlier fracture union. A prospective, double-blind, randomized controlled trial (RCT) will be conducted in an academic medical center in the Netherlands. Ethics approval is received. 50 patients will be randomized to either operative treatment with cB + cBMA, harvested from the iliac crest, or operative treatment without cB + cBMA but with a sham-treatment of the iliac crest. The fracture fixation is the same in both groups, as is the post-operative care.. Follow up will be one year. The primary outcome measure is time to union in weeks on X-ray. Secondary outcome measures are time to resumption of work and sports, functional outcomes (SF-36, FAOS, FAAM), complication rate, composition of osteoprogenitors in cB + cBMA and cost-effectiveness. Furthermore, a bone biopsy is taken from every stress fracture and analysed histologically to determine the stage of the stress fracture. The difference in primary endpoint between the two groups is analysed using student's t-test or equivalent. This trial will likely provide level-I evidence on the effectiveness of cB + cBMA in the operative treatment of MT-V stress fractures. Netherlands Trial Register (reg.nr NTR4377 ).

49 CFR 195.452 - Pipeline integrity management in high consequence areas.

Code of Federal Regulations, 2010 CFR

2010-10-01

...; or (D) Other technology that the operator demonstrates can provide an equivalent understanding of the... information, coating type and condition, and seam type; (iii) Leak history, repair history and cathodic protection history; (iv) Product transported; (v) Operating stress level; (vi) Existing or projected...

The Influence of Oral Carbohydrate Solution Intake on Stress Response before Total Hip Replacement Surgery during Epidural and General Anaesthesia.

PubMed

Çeliksular, M Cem; Saraçoğlu, Ayten; Yentür, Ercüment

2016-06-01

The effects of oral carbohydrate solutions, ingested 2 h prior to operation, on stress response were studied in patients undergoing general or epidural anaesthesia. The study was performed on 80 ASA I-II adult patients undergoing elective total hip replacement, which were randomized to four groups (n=20). Group G patients undergoing general anaesthesia fasted for 8 h preoperatively; Group GN patients undergoing general anaesthesia drank oral carbohydrate solutions preoperatively; Group E patients undergoing epidural anaesthesia fasted for 8 h and Group EN patients undergoing epidural anaesthesia drank oral carbohydrate solutions preoperatively. Groups GN and EN drank 800 mL of 12.5% oral carbohydrate solution at 24:00 preoperatively and 400 mL 2 h before the operation. Blood samples were taken for measurements of glucose, insulin, cortisol and IL-6 levels. The effect of preoperative oral carbohydrate ingestion on blood glucose levels was not significant. Insulin levels 24 h prior to surgery were similar; however, insulin levels measured just before surgery were 2-3 times higher in groups GN and EN than in groups G and E. Insulin levels at the 24(th) postoperative hour in epidural groups were increased compared to those at basal levels, although general anaesthesia groups showed a decrease. From these measurements, only the change in Group EN was statistically significant (p<0.05). Plasma cortisol levels at the 2(nd) peroperative hour were higher in epidural groups than in general anaesthesia groups. Both anaesthesia techniques did not have an effect on IL-6 levels. We concluded that epidural anaesthesia suppressed stress response, although preoperative oral carbohydrate nutrition did not reveal a significant effect on surgical stress response.

Association Between Selenium and Malondialdehyde as an Efficient Biomarker of Oxidative Stress in Infantile Cardiac Surgery.

PubMed

de Oliveira Ulbrecht, Marlice Oliveira; Gonçalves, Daniel Araujo; Zanoni, Lourdes Zélia Garcia; do Nascimento, Valter Aragão

2018-05-12

The present work describes a method to quantify the level of oxidative stress in infantile cardiac surgery. Fifteen patients, 6 girls and 9 boys, aged between 3 months and 16 years were divided into three groups. The first group sought to quantify the oxidative stress from differing concentrations of selenium. The second group used malondialdehyde as an indicator of oxidative stress. Finally, the third group quantified oxidative stress by normalizing the selenium concentration via malondialdehyde. Blood aliquots of 1.50 ml, drawn from the radial artery, were collected and centrifuged for quantification of Se and MDA in plasma. The statistical method ANOVA was used with a 95% confidence interval to indicate significant statistical differences between the post- and pre-operative stage for each group. The concentrations of malondialdehyde were measured by using UV-Vis following the thiobarbituric acid reaction method. For quantification of selenium, the samples were submitted to assisted microwave digestion and measured by ICP OES. In the first two groups, it was not possible to affirm that selenium and malondialdehyde could be biomarkers of oxidative stress, so a statistic test (ANOVA) was performed. However, the selenium/malondialdehyde ratios in the pre-operative and post-operative stage were 2.10 ± 0.70 and 3.20 ± 0.40, respectively. The ANOVA test confirmed a statistically significant difference between the pre- and post-operative stages with p value = 0.004. Here, the ratio of selenium concentration by malondialdehyde was confirmed to be an effective parameter for demonstration and quantification of oxidative stress activity at the post-operative stage.

Effects of routine handling and tagging procedures on physiological stress responses in juvenile chinook salmon

USGS Publications Warehouse

Sharpe, C.S.; Thompson, D.A.; Blankenship, H.L.; Schreck, C.B.

1998-01-01

Juvenile chinook salmon Oncorhynchus tshawytscha were subjected to handling and tagging protocols typical of normal hatchery operations and monitored for their physiological response to stress. Treatments included coded-wire-tagging, counting, ventral fin clipping, adipose fin clipping, and a procedure simulating a pond split. Treatment fish were also subjected to a standardized stress challenge (1 h confinement) to evaluate their ability to deal with disturbances subsequent to a handling or tagging procedure. Circulating levels of cortisol and glucose were used as indicators of stress. Each of the treatments elicited very similar responses among treatment groups. Cortisol increased from resting levels of about 20 ng/mL to about 90 ng/mL by 1 h poststress and returned to near resting levels by 8 h poststress. Glucose levels increased from 50 mg/dL to about 80 mg/dL by 1 h poststress and remained elevated for much of the experiment. The cortisol and glucose responses to the confinement stress did not differ over time or among treatments. However, the confinement stress results do suggest a small but significant cumulative response, indicating small residual effects of the original handling protocols. No deaths were noted among treatment groups.

[Heart Rate Variability as an Indicator of Mental Stress in Surgeons - A Review of the Literature].

PubMed

Thielmann, B; Boeckelmann, I

2016-10-01

The risk assessment of mental stress and early detection of mental illness among surgeons are much debated issues, because the perceived working conditions are important for their own health and that of the patients. Studies of predominantly mental stress are increasing and stay up-to-date. The psychological strain of surgeons is generally regarded as high. In order to objectively determine stress, the heart rate and its variability have been established as parameters. Based on the physiological stress parameter, it is possible to determine the previous level of strain. This work presents a summary of recent scientific studies to explore the stress in operative surgeons on the basis of the physiological stress parameters heart rate (HR) and heart rate variability (HRV). A PubMed search until spring of 2014 was performed. A total of 10 studies were included which deal with the mental stress and strain analysis by surgeons. In this case, 4 studies used only the HR and the further 6 studies used the HRV as a stress parameter. First stress and strain analyses of surgeons have been around since the early 1980s. The studies were usually carried out solely within the sample examined. Control groups have rarely or not been studied. In summary, stressed surgeons offered a higher intraoperative heart rate and a low expression of the HRV. The same was experienced in operating surgeons compared to the assistant surgeons or with inexperienced operating surgeons compared to experienced surgeons. Georg Thieme Verlag KG Stuttgart · New York.

Farm Crisis Response: Extension and Research Activities in the North Central Region.

ERIC Educational Resources Information Center

Lasley, Paul, Comp.; And Others

The 12 states comprising the North Central Region have been affected in similar ways by the farm crisis of the 1980s. Statewide surveys show sizeable proportions of farm operations that are experiencing moderately high levels of financial stress. The problems caused by chronic stress on family structure and functioning, the loss of mainstreet…

Informational need of emotional stress

NASA Astrophysics Data System (ADS)

Simonov, P. V.; Frolov, M. V.

According to the informational theory of emotions[1], emotions in humans depend on the power of some need (motivation) and the estimation by the subject of the probability (possibility) of the need staisfaction (the goal achievement). Low probability of need satisfaction leads to negative emotions, actively minimized by the subject. Increased probability of satisfaction, as compared to earlier forecast, generates positive emotions, which the subject tries to maximize, i.e. to enhance, to prolong, to repeat. The informational theory of emotions encompasses their reflective function, the laws of their appearance, the regulatory significance of emotions, and their role in organization of behavior. The level of emotional stress influences the operator's performance. A decrease in the emotional tonus leads to drowsiness, lack of vigilance, missing of significant signals and to slower reactions. An extremely high stress level disorganizes the activity, complicates it with a trend toward incorrect actions and reactions to insignificant signals (false alarms). The neurophysiological mechanisms of the influence of emotions on perceptual activity and operator performance as well as the significance of individuality are discussed.

Heart Rate Variability as a Measure of Airport Ramp-Traffic Controllers Workload

NASA Technical Reports Server (NTRS)

Hayashi, Miwa; Dulchinos, Victoria Lee

2016-01-01

Heart Rate Variability (HRV) has been reported to reflect the person's cognitive and emotional stress levels, and may offer an objective measure of human-operator's workload levels, which are recorded continuously and unobtrusively to the task performance. The present paper compares the HRV data collected during a human-in-the-loop simulation of airport ramp-traffic control operations with the controller participants' own verbal self-reporting ratings of their workload.

Intraindividual change and variability in daily stress processes: Findings from two measurement-burst diary studies

PubMed Central

Sliwinski, Martin J.; Almeida, David M.; Smyth, Joshua; Stawski, Robert S.

2010-01-01

There is little longitudinal information on aging-related changes in emotional responses to negative events. The present manuscript examined intraindividual change and variability in the within-person coupling of daily stress and negative affect (NA) using data from two-measurement burst daily diary studies. Three main findings emerged. First, average reactivity to daily stress increased longitudinally, and this increase was evident across most the adult lifespan. Second, individual differences in emotional reactivity to daily stress exhibited long-term temporal stability, but this stability was greatest in midlife and decreased in old age. And third, reactivity to daily stress varied reliably within-persons (across-time), with individual exhibiting higher levels of reactivity during times when reporting high levels of global subject stress in previous month. Taken together, the present results emphasize the importance of modeling dynamic psychosocial and aging processes that operate across different time scales for understanding age-related changes in daily stress processes. PMID:20025399

A case study employing operant conditioning to reduce stress of capture for red-bellied tamarins (Saguinus labiatus).

PubMed

Owen, Yvonne; Amory, Jonathan R

2011-01-01

Traditional techniques used to capture New World monkeys, such as net capture, can induce high levels of acute stress detrimental to welfare. Alternatively, training nonhuman animals via operant conditioning to voluntarily participate in husbandry and/or veterinary practices is accepted as a humane process that can reduce stress and improve welfare. This study details the use of operant conditioning using positive reinforcement training (PRT) and target training to train a family of 5 captive red-bellied tamarins (Saguinus labiatus) in a wildlife park to voluntarily enter a transportation box and remain calm for 1 min after 54 training sessions. Observations of 2 unrelated net-capture processes provided measures of locomotion and vocalizations as indicators of stress behavior that were compared with those of the trained tamarins. Net-captured monkeys exhibited rapid erratic locomotion and emitted long, high-frequency vocalizations during capture whereas the trained tamarins exhibited minimal locomotion and emitted only 4 brief vocalizations (root mean square 35 dB) during capture. This indicates that the use of PRT considerably reduced potential for stress and improved welfare during the capture and containment of the tamarins. Copyright © Taylor & Francis Group, LLC

The role of fracture mechanics in the design of fuel tanks in space vehicles

NASA Technical Reports Server (NTRS)

Denton, S. J.; Liu, C. K.

1976-01-01

With special reference to design of fuel tanks in space vehicles, the principles of fracture mechanics are reviewed. An approximate but extremely simple relationship is derived among the operating stress level, the length of crack, and the number of cycles of failure. Any one of the variables can be computed approximately from the knowledge of the other two, if the loading schedule (mission of the tank) is not greatly altered. Two sample examples illustrating the procedures of determining the allowable safe operating stress corresponding to a set of assumed loading schedule are included. The selection of sample examples is limited by the relatively meager available data on the candidate material for various stress ratios in the cycling.

Expression of endothelin-1 and constitutional nitric oxide synthase messenger RNA in saphenous vein endothelial cells exposed to arterial flow shear stress.

PubMed

Zhu, Z G; Li, H H; Zhang, B R

1997-11-01

It has long been speculated that increased blood flow shear stress might be one of the major factors affecting the patency of grafted saphenous vein in coronary artery bypass operations. The underlying cellular and molecular mechanisms for so-called "shear stress damage" have not yet been well elucidated. Endothelial cells harvested from human saphenous vein were cultured in vitro and then exposed to a high arterial level flow shear stress in the parallel flow chamber. The expression levels of endothelin-1 and constitutional nitric oxide synthase by the endothelial cells were evaluated semiquantitatively at the gene transcription (messenger RNA) level using reverse transcription polymerase chain reaction. After 7 hours of exposure to arterial level shear stress, the expression of constitutional nitric oxide synthase messenger RNA by saphenous vein endothelial cells was significantly reduced, whereas the expression of endothelin-1 messenger RNA was substantially increased. These changes were more predominant at 24 hours. Arterial level flow shear stress could cause important changes in the gene transcription level in saphenous vein endothelial cells within a short period of time. The functional alterations of saphenous vein endothelial cells, as manifested by the increased expression of endothelin-1 and decreased expression of nitric oxide synthase messenger RNA, might play a crucial role in the vein graft remodeling process.

Perceived job stress and health complaints at a bank call center: comparison between inbound and outbound services.

PubMed

Lin, Yen-Hui; Chen, Chih-Yong; Hong, Wei-Hsien; Lin, Yu-Chao

2010-01-01

This study investigated how perceived job stress and health status differ, as well as the relationships to inbound (incoming calls) versus outbound (outgoing calls) calling activities, for call center workers in a bank in Taiwan. The sample bank employed 289 call center workers at the time of the survey, ranging in age from 19 to 54 yr old. Data were obtained on individual factors, health complaints, perceived level job stress, and major job stressors. Overall, 33.5% of outbound operators and 27.1% of inbound operators reported frequently or always experiencing high stress at work, however, the differences between inbound and outbound operators were insignificant. "Having to deal with difficult customers" was the most frequent job stressor for all workers. Musculoskeletal discomfort, eye strain, and hoarse or sore throat were the most prevalent complaints among call center workers. The relationship between perceived job stress and health complaints indicated that workers who perceived higher job stress had significantly increased risk of multiple health problems, including eye strain, tinnitus, hoarse or sore throat, chronic cough with phlegm, chest tightness, irritable stomach or peptic ulcers, and musculoskeletal discomfort (with odds ratios ranging from 2.13 to 8.24). These analytical results suggest that perceived job stress in the call center profoundly affected worker health. This study identified main types of job stressors requiring further investigation.

Identification of human operator performance models utilizing time series analysis

NASA Technical Reports Server (NTRS)

Holden, F. M.; Shinners, S. M.

1973-01-01

The results of an effort performed by Sperry Systems Management Division for AMRL in applying time series analysis as a tool for modeling the human operator are presented. This technique is utilized for determining the variation of the human transfer function under various levels of stress. The human operator's model is determined based on actual input and output data from a tracking experiment.

Chronic exposure to emissions from photocopiers in copy shops causes oxidative stress and systematic inflammation among photocopier operators in India.

PubMed

Elango, Nithya; Kasi, Vallikkannu; Vembhu, Bhuvaneswari; Poornima, Jeyanthi Govindasamy

2013-09-11

We assessed indoor air quality in photocopier centers and investigated whether occupational exposure to emissions from photocopiers is associated with decline in lung function or changes in haematological parameters, oxidative stress and inflammatory status. Indoor air quality was monitored in five photocopier centers. Pulmonary function was assessed by spirometry in 81 photocopier operators (64 male and 17 female) and 43 healthy control (31 male and 12 female) subjects. Hematological status, serum thio-barbituric acid reactive substances (TBARS), total ferric reducing antioxidant capacity (FRAC), leukotriene B4 (LTB4), 8-isoprostane, C reactive protein (CRP), interleukin 8 (IL-8), clara cell protein (CC-16), intercellular adhesion molecule 1 (ICAM-1) and eosinophilic cationic protein (ECP) were analyzed. Relationships between cumulative exposure, lung function and inflammatory markers were assessed. PM10 and PM2.5 were above the permissible levels in all the photocopier centers, whereas the levels of carbon monoxide, nitrogen oxides, ozone, sulphur dioxide, lead, arsenic, nickel, ammonia, benzene and benzo(a)pyrene were within Indian ambient air quality standards. Lung function was similar in the photocopier operators and control subjects. Serum TBARS was significantly higher and FRAC was lower among photocopier operators when compared to healthy controls. Plasma IL-8, LTB4, ICAM-1 and ECP were significantly higher in the photocopier exposed group. Photocopiers emit high levels of particulate matter. Long term exposure to emissions from photocopiers was not associated with decreased lung function, but resulted in high oxidative stress and systemic inflammation leading to high risk of cardiovascular diseases.

Chronic exposure to emissions from photocopiers in copy shops causes oxidative stress and systematic inflammation among photocopier operators in India

PubMed Central

2013-01-01

Background We assessed indoor air quality in photocopier centers and investigated whether occupational exposure to emissions from photocopiers is associated with decline in lung function or changes in haematological parameters, oxidative stress and inflammatory status. Methods Indoor air quality was monitored in five photocopier centers. Pulmonary function was assessed by spirometry in 81 photocopier operators (64 male and 17 female) and 43 healthy control (31 male and 12 female) subjects. Hematological status, serum thio-barbituric acid reactive substances (TBARS), total ferric reducing antioxidant capacity (FRAC), leukotriene B4 (LTB4), 8-isoprostane, C reactive protein (CRP), interleukin 8 (IL-8), clara cell protein (CC-16), intercellular adhesion molecule 1 (ICAM-1) and eosinophilic cationic protein (ECP) were analyzed. Relationships between cumulative exposure, lung function and inflammatory markers were assessed. Results PM10 and PM2.5 were above the permissible levels in all the photocopier centers, whereas the levels of carbon monoxide, nitrogen oxides, ozone, sulphur dioxide, lead, arsenic, nickel, ammonia, benzene and benzo(a)pyrene were within Indian ambient air quality standards. Lung function was similar in the photocopier operators and control subjects. Serum TBARS was significantly higher and FRAC was lower among photocopier operators when compared to healthy controls. Plasma IL-8, LTB4, ICAM-1 and ECP were significantly higher in the photocopier exposed group. Conclusions Photocopiers emit high levels of particulate matter. Long term exposure to emissions from photocopiers was not associated with decreased lung function, but resulted in high oxidative stress and systemic inflammation leading to high risk of cardiovascular diseases. PMID:24025094

The Design and Implementation of INGRES.

ERIC Educational Resources Information Center

Stonebraker, Michael; And Others

The currently operational version of the INGRES data base management system gives a relational view of data, supports two high level, non-procedural data sublanguages, and runs as a collection of user processes on top of a UNIX operating system. The authors stress the design decisions and tradeoffs in relation to (1) structuring the system into…

Operation Parenting Edge: Promoting Resiliency through Prevention

ERIC Educational Resources Information Center

Yeary, Julia

2007-01-01

With current U.S. combat operations in Afghanistan and Iraq, military families are facing an unprecedented level of stress because of repeated and lengthy separations. The impact on children of these separations from one or both parents depends to a large extent on the remaining caregiver's ability to respond to the needs of the children. By…

METRO-APEX Volume 2.1: Computer Operator's Manual. Revised.

ERIC Educational Resources Information Center

University of Southern California, Los Angeles. COMEX Research Project.

The Computer Operator's Manual is one of a set of twenty-one manuals used in METRO-APEX 1974, a computerized college and professional level, computer-supported, role-play, simulation exercise of a community with "normal" problems. Stress is placed on environmental quality considerations. APEX 1974 is an expansion of APEX--Air Pollution…

Reduction of oxidative stress by compression stockings in standing workers.

PubMed

Flore, Roberto; Gerardino, Laura; Santoliquido, Angelo; Catananti, Cesare; Pola, Paolo; Tondi, Paolo

2007-08-01

Healthy workers who stand for prolonged periods show enhanced production of reactive oxygen species (ROS) in their systemic circulation. Oxidative stress is thought to be a risk factor for chronic venous insufficiency and other systemic diseases. To evaluate the effectiveness of compression stockings in the prevention of oxidative stress at work. ROS and venous pressure of the lower limbs were measured in 55 theatre nurses who stood in the operating theatre for >6 h, 23 industrial ironers who stood for up to 5 h during their shift and 65 outpatient department nurses and 35 laundry workers who acted as controls. Subjects and controls were examined on two consecutive days before and after work and with and without compression stockings. Without compression stockings, lower limb venous pressure increased significantly after work in all subjects and controls (P < 0.001), while only operating theatre nurses showed significantly higher mean levels of ROS (P < 0.001). There was no significant difference in venous pressures and ROS levels after work in subjects or controls when wearing compression stockings. Our data suggest a preventive role of compression stockings against oxidative stress in healthy workers with a standing occupation.

Analysis of Limitations Imposed on One-spool Turboprop-engine Designs by Compressors and Turbines at Flight Mach Numbers of 0, 0.6, and 0.8

NASA Technical Reports Server (NTRS)

Cavicchi, Richard H

1956-01-01

Turbine centrifugal stress is a limiting factor for all flight conditions studied. This stress is more severe for sea-level operations than for subsonic flight at the tropopause. Turbines designed for a stress of 30,000 psi are capable of driving a light, compact, high-spedd compressor but only at high values of specific fuel consumption. An increase in turbine-inlet temperature is accompanied by an increase in turbine centrifugal stress. If stresses in excess of 50,000 psi can be tolerated, compressor aerodynamics may become a primary limitation.

Preliminary Thermal Stress Analysis of a High-Pressure Cryogenic Storage Tank

NASA Technical Reports Server (NTRS)

Baker, J. Mark

2003-01-01

The thermal stresses on a cryogenic storage tank strongly affect the condition of the tank and its ability to withstand operational stresses. These thermal stresses also affect the growth of any surface damage that might occur in the tank walls. These stresses are particularly of concern during the initial cooldown period for a new tank placed into service, and during any subsequent thermal cycles. A preliminary thermal stress analysis of a high-pressure cryogenic storage tank was performed. Stresses during normal operation were determined, as well as the transient temperature distribution. An elastic analysis was used to determine the thermal stresses in the inner wall based on the temperature data. The results of this elastic analysis indicate that the inner wall of the storage tank will experience thermal stresses of approximately 145,000 psi (1000 MPa). This stress level is well above the room-temperature yield strength of 304L stainless steel, which is about 25,000 psi (170 MPa). For this preliminary analysis, several important factors have not yet been considered. These factors include increased strength of 304L stainless steel at cryogenic temperatures, plastic material behavior, and increased strength due to strain hardening. In order to more accurately determine the thermal stresses and their affect on the tank material, further investigation is required, particularly in the area of material properties and their relationship to stress.

On the Home Front: Stress for Recently Deployed Army Couples

PubMed Central

Allen, Elizabeth S.; Rhoades, Galena K.; Stanley, Scott M.; Markman, Howard J.

2014-01-01

Military couples who have experienced deployment and reintegration in current U.S. military operations frequently experience stress regarding the dangers and effects of such experiences. The current study evaluated a sample of 300 couples with an active duty Army husband and civilian spouse who experienced a deployment within the year prior to the survey (conducted in 2007). Wives generally reported greater levels of emotional stress compared to husbands. Overall, higher levels of stress were found for couples who reported lower income and greater economic strain, perceive the need for more support and are unsure about how to get support, have more marital conflict, and are generally less satisfied with the Army and the current mission. Husband combat exposure was also associated with more stress for husbands and wives. Additionally, for wives, stress was related to greater child behavior problems and a sense of less Army concern for families. The results suggest areas of intervention with military couples to help them cope with the challenges of military life and deployment. PMID:21564063

Subjective rating scales as a workload

NASA Technical Reports Server (NTRS)

Bird, K. L.

1981-01-01

A multidimensional bipolar-adjective rating scale is employed as a subjective measure of operator workload in the performance of a one-axis tracking task. The rating scale addressed several dimensions of workload, including cognitive, physical, and perceptual task loading as well as fatigue and stress effects. Eight subjects performed a one-axis tracking task (with six levels of difficulty) and rated these tasks on several workload dimensions. Performance measures were tracking error RMS (root-mean square) and the standard deviation of control stick output. Significant relationships were observed between these performance measures and skill required, task complexity, attention level, task difficulty, task demands, and stress level.

Oxidative stress induces vascular heme oxygenase-1 expression in ovariectomized rats.

PubMed

Lee, Yen-Mei; Cheng, Pao-Yun; Hong, Su-Fen; Chen, Shu-Ying; Lam, Kwok-Keung; Sheu, Joen-Rong; Yen, Mao-Hsiung

2005-07-01

Heme oxygenase-1 (HO-1), an inducible stress protein, has been implicated in cytoprotection against oxidative stress in vitro and in vivo. Estrogens also have antioxidant effects. This study investigated the time course of HO-1 and inducible nitric oxide synthase (iNOS) expression in the aortas of ovariectomized rats, and the regulatory relationship between the NO/NOS and the carbon monoxide/HO systems. HO-1 and iNOS protein expression was induced by ovariectomy (Ovx) and was extremely high 2-6 weeks after Ovx compared with the sham-operated group. Expression of the constitutive enzymes HO-2 and endothelial NOS did not differ significantly between sham-operated and Ovx rats. 17beta-Estradiol (E(2)) replacement reversed these changes in rats after Ovx. Long-term treatment with the antioxidant tempol significantly inhibited HO-1 and iNOS expression. The iNOS inhibitor aminoguanidine significantly suppressed the induction of HO-1. Oxidized glutathione in the hearts of Ovx rats increased gradually, with significant elevation at 3-6 weeks after Ovx compared with the sham-operated group, whereas plasma levels of NO metabolites were significantly reduced 4-6 weeks after Ovx. Treatment with the HO inhibitor zinc protoporphyrin IX blocked HO-1 induction, but significantly increased the plasma levels of NO metabolites. In conclusion, HO-1 is induced by oxidative stress resulting from E(2) depletion. The NO/iNOS system contributes to the induction of HO-1, which may subsequently suppress iNOS activity to modulate vasculoprotective effects after menopause.

The role of cognitive style in the stress and coping of black South African adolescents.

PubMed

van Rooyen, Melinda; Naude, Luzelle; Nel, Lindi; Esterhuyse, Karel

2014-12-01

Although stress is a common phenomenon in all phases of life, it can be said that adolescence is a particularly stressful life stage. In South Africa, black adolescents are faced with many stressors and challenges which are placing demands on their emotional and cognitive resources. The aim of this study was to determine whether black South African adolescents with different cognitive styles (i.e. rational or experiential) differ in their levels of stress and coping. Furthermore, the common stressors that black adolescents experience and the coping styles predominantly used by black adolescents could be determined. One hundred and eighty-seven participants (88 males and 99 females) completed the Rational Experiential, the Coping Reponses and the Adolescent Stress Inventory. Adolescents operating from an experiential cognitive style experienced more stress regarding school performance, school attendance, financial pressure and emerging adult responsibility than adolescents operating from a rational cognitive style. Adolescents employing a rational style sought more alternative rewards as a coping strategy, whereas adolescents employing an experiential style relied more on emotional discharge. The findings of this study concur with previous research, but provide a unique perspective on adolescents' stress and coping in this South African context.

Examination of the Relationship between Organizational Stress and Employee Performance: A Research on Staff Working on Provincial Directorate of Youth and Sports

ERIC Educational Resources Information Center

Goksel, Ali Gurel; Caz, Cagdas; Yazici, Omer Faruk; Ikizler, Huseyin Can

2017-01-01

The purpose of this research is to study the relation between the level of organizational stress at the staff of the Youth Services and Sports Provincial Directorate and their performance. The study group of research, Istanbul province in the Uskudar district officials operating in the Youth Services and Sports Provincial Directorate constitute a…

A modeling study on the thermomechanical behavior of glass-ceramic and self-healing glass seals at elevated temperatures

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

Govindaraju, Nirmal; Liu, Wenning N.; Sun, Xin

Hermetic gas seals are critical components for planar solid oxide fuel cells. This article focuses on comparative evaluation of a glass-ceramic developed by the Pacific Northwest National Laboratory (PNNL) and a self-healing glass seal developed by the University of Cincinnati. The stress and strain levels in the Positive electrode-Electrolyte-Negative electrode (PEN) seal in one cell stack are evaluated using a multi-physics simulation package developed at PNNL. Simulations were carried out with and without consideration of clamping force and stack body force, respectively. The results indicate that the overall stress and strain levels are dominated by the thermal expansion mismatches betweenmore » the different cell components. Further, compared with glass-ceramic seal, the self-healing glass seal results in much lower steady state stress due to its much lower stiffness at the operating temperature of SOFC, and also exhibits much shorter relaxation times due to high creep rate. It is also noted that the self-healing glass seal will experience continuing creep deformation under the operating temperature of SOFC therefore resulting in possible overflow of the sealing materials. Further stopper material may need to be added to maintain its geometric stability during operation.« less

Does stress mediate the association between personal relative deprivation and gambling?

PubMed

Mishra, Sandeep; Meadows, Tyler J S

2018-04-01

Evidence has linked subjective feelings of personal relative deprivation with general gambling involvement and problem gambling tendencies. In turn, problem gambling tendencies have been linked with a wide array of damaging physical and mental health consequences. It has been theorized that the deleterious effects of perceived inequality on mental and physical health operate at the individual level through the experience of personal relative deprivation leading to psychosocial stress. We empirically examined whether the experience of perceived stress contributes to explaining the deprivation-gambling link using cross-sectional, self-reported survey data collected from a crowdsourced population of adults (n = 565). Results indicate that personal relative deprivation is associated with problem gambling tendencies (but not general gambling involvement) and that this association is mediated by perceived stress. These associations were particularly strong among participants who reported non-zero levels of problem gambling tendencies. Together, our results further emphasize the importance of individual-level social comparison reactions in the context of health. Copyright © 2017 John Wiley & Sons, Ltd.

Ergonomic analysis of primary and assistant surgical roles.

PubMed

Zihni, Ahmed M; Cavallo, Jaime A; Ray, Shuddhadeb; Ohu, Ikechukwu; Cho, Sohyung; Awad, Michael M

2016-06-15

Laparoscopic surgery is associated with a high degree of ergonomic stress. However, the stress associated with surgical assisting is not known. In this study, we compare the ergonomic stress associated with primary and assistant surgical roles during laparoscopic surgery. We hypothesize that higher ergonomic stress will be detected in the primary operating surgeon when compared with the surgical assistant. One right-hand dominant attending surgeon performed 698 min of laparoscopic surgery over 13 procedures (222 min primary and 476 min assisting), whereas electromyography data were collected from bilateral biceps, triceps, deltoids, and trapezius muscles. Data were analyzed in 1-min segments. Average muscle activation as quantified by maximal voluntary contraction (%MVC) was calculated for each muscle group during primary surgery and assisting. We compared mean %MVC values with unpaired t-tests. Activation of right (R) biceps and triceps muscle groups is significantly elevated while operating when compared with assisting (R biceps primary: 5.47 ± 0.21 %MVC, assistant: 3.93 ± 0.11, P < 0.001; R triceps primary: 6.53 ± 0.33 %MVC, assistant: 5.48 ± 0.18, P = 0.002). Mean activation of the left trapezius muscle group is elevated during assisting (primary: 4.33 ± 0.26 %MVC, assistant: 5.70 ± 0.40, P = 0.024). No significance difference was noted in the other muscle groups (R deltoid, R trapezius, left [L] biceps, L triceps, and L deltoid). We used surface electromyography to quantify ergonomic differences between operating and assisting. Surgical assisting was associated with similar and occasionally higher levels of muscle activation compared with primary operating. These findings suggest that surgical assistants face significant ergonomic stress, just as operating surgeons do. Steps must be taken to recognize and mitigate this stress in both operating surgeons and assistants. Copyright © 2016 Elsevier Inc. All rights reserved.

Biomonitoring of physiological status and cognitive performance of underway submariners undergoing a novel watch-standing schedule

NASA Astrophysics Data System (ADS)

Duplessis, C. A.; Cullum, M. E.; Crepeau, L. J.

2005-05-01

Submarine watch-standers adhere to a 6 hour-on, 12 hour-off (6/12) watch-standing schedule, yoking them to an 18-hr day, engendering circadian desynchronization and chronic sleep deprivation. Moreover, the chronic social crowding, shift work, and confinement of submarine life provide additional stressors known to correlate with elevated secretory immunoglobulin A (sIgA) and cortisol levels, reduced performance, immunologic dysfunction, malignancies, infections, gastrointestinal illness, coronary disease, anxiety, and depression. We evaluated an alternative, compressed, fixed work schedule designed to enhance circadian rhythm entrainment, sleep hygiene, performance, and health on 10 underway submariners, who followed the alternative and 6/12 schedules for approximately 2 weeks each. We measured subjects" sleep, cognitive performance, and salivary biomarker levels. Pilot analysis of the salivary data on one subject utilizing ELISA suggests elevated biomarker levels of stress. Average PM cortisol levels were 0.2 μg/L (normal range: nondetectable - 0.15 μg/L), and mean sIgA levels were 562 μg/ml (normal range: 100-500 μg/ml). Future research exploiting real-time salivary bioassays, via fluorescent polarimetry technology, identified by the Office of Naval Research (ONR) as a future Naval requirement, allows researchers to address correlations between stress-induced elaboration of salivary biomarkers with physiological and performance decrements, thereby fostering insight into the underway submariner"s psychoimmunological status. This may help identify strategies that enhance resilience to stressors. Specifically, empirically-based modeling can identify optimal watch-standing schedules and stress-mitigating procedures -- within the operational constraints of the submarine milieu and the mission --that foster improved circadian entrainment and reduced stress reactivity, enhancing physiological health, operational performance, safety, and job satisfaction.

Effects of Drought on Gene Expression in Maize Reproductive and Leaf Meristem Tissue Revealed by RNA-Seq1[W][OA

PubMed Central

Kakumanu, Akshay; Ambavaram, Madana M.R.; Klumas, Curtis; Krishnan, Arjun; Batlang, Utlwang; Myers, Elijah; Grene, Ruth; Pereira, Andy

2012-01-01

Drought stress affects cereals especially during the reproductive stage. The maize (Zea mays) drought transcriptome was studied using RNA-Seq analysis to compare drought-treated and well-watered fertilized ovary and basal leaf meristem tissue. More drought-responsive genes responded in the ovary compared with the leaf meristem. Gene Ontology enrichment analysis revealed a massive decrease in transcript abundance of cell division and cell cycle genes in the drought-stressed ovary only. Among Gene Ontology categories related to carbohydrate metabolism, changes in starch and Suc metabolism-related genes occurred in the ovary, consistent with a decrease in starch levels, and in Suc transporter function, with no comparable changes occurring in the leaf meristem. Abscisic acid (ABA)-related processes responded positively, but only in the ovaries. Related responses suggested the operation of low glucose sensing in drought-stressed ovaries. The data are discussed in the context of the susceptibility of maize kernel to drought stress leading to embryo abortion and the relative robustness of dividing vegetative tissue taken at the same time from the same plant subjected to the same conditions. Our working hypothesis involves signaling events associated with increased ABA levels, decreased glucose levels, disruption of ABA/sugar signaling, activation of programmed cell death/senescence through repression of a phospholipase C-mediated signaling pathway, and arrest of the cell cycle in the stressed ovary at 1 d after pollination. Increased invertase levels in the stressed leaf meristem, on the other hand, resulted in that tissue maintaining hexose levels at an “unstressed” level, and at lower ABA levels, which was correlated with successful resistance to drought stress. PMID:22837360

Training the combat and operational stress control dog: an innovative modality for behavioral health.

PubMed

Krol, William

2012-01-01

Combat and operational stress control (COSC) dogs represent a new category of military working dog. America's VetDogs, a nongovernmental, not-for-profit organization, trains and provides therapy dogs to work with the US Army's combat and operational stress control teams deployed to Afghanistan or Iraq. By taking the therapy/service dog concept to the next level, these dogs have become an important modality in the Army's initiative to safeguard Soldiers' behavioral health while deployed, allowing COSC unit members to break down stigmas that are still present when dealing with behavioral health issues. The training process begins by choosing a pool of dogs, exposing them to different sensory experiences over several months, and training the primary and secondary handlers who will be responsible for the dogs while deployed in theater. After their deployment ends, the dogs are retrained by America's VetDogs to further serve in military or Veterans Administration medical centers as physical, occupational, or behavioral therapy dogs.

The Independence and Interdependence of Coacting Observers in Regard to Performance Efficiency, Workload, and Stress in a Vigilance Task.

PubMed

Funke, Gregory J; Warm, Joel S; Baldwin, Carryl L; Garcia, Andre; Funke, Matthew E; Dillard, Michael B; Finomore, Victor S; Matthews, Gerald; Greenlee, Eric T

2016-09-01

We investigated performance, workload, and stress in groups of paired observers who performed a vigilance task in a coactive (independent) manner. Previous studies have demonstrated that groups of coactive observers detect more signals in a vigilance task than observers working alone. Therefore, the use of such groups might be effective in enhancing signal detection in operational situations. However, concern over appearing less competent than one's cohort might induce elevated levels of workload and stress in coactive group members and thereby undermine group performance benefits. Accordingly, we performed the initial experiment comparing workload and stress in observers who performed a vigilance task coactively with those of observers who performed the vigilance task alone. Observers monitored a video display for collision flight paths in a simulated unmanned aerial vehicle control task. Self-reports of workload and stress were secured via the NASA-Task Load Index and the Dundee Stress State Questionnaire, respectively. Groups of coactive observers detected significantly more signals than did single observers. Coacting observers did not differ significantly from those operating by themselves in terms of workload but did in regard to stress; posttask distress was significantly lower for coacting than for single observers. Performing a visual vigilance task in a coactive manner with another observer does not elevate workload above that of observers working alone and serves to attenuate the stress associated with vigilance task performance. The use of coacting observers could be an effective vehicle for enhancing performance efficiency in operational vigilance. © 2016, Human Factors and Ergonomics Society.

The Glycerate and Phosphorylated Pathways of Serine Synthesis in Plants: The Branches of Plant Glycolysis Linking Carbon and Nitrogen Metabolism.

PubMed

Igamberdiev, Abir U; Kleczkowski, Leszek A

2018-01-01

Serine metabolism in plants has been studied mostly in relation to photorespiration where serine is formed from two molecules of glycine. However, two other pathways of serine formation operate in plants and represent the branches of glycolysis diverging at the level of 3-phosphoglyceric acid. One branch (the glycerate - serine pathway) is initiated in the cytosol and involves glycerate formation from 3-phosphoglycerate, while the other (the phosphorylated serine pathway) operates in plastids and forms phosphohydroxypyruvate as an intermediate. Serine formed in these pathways becomes a precursor of glycine, formate and glycolate accumulating in stress conditions. The pathways can be linked to GABA shunt via transamination reactions and via participation of the same reductase for both glyoxylate and succinic semialdehyde. In this review paper we present a hypothesis of the regulation of redox balance in stressed plant cells via participation of the reactions associated with glycerate and phosphorylated serine pathways. We consider these pathways as important processes linking carbon and nitrogen metabolism and maintaining cellular redox and energy levels in stress conditions.

Stress Fractures of the Foot and Ankle in Athletes

PubMed Central

Mayer, Stephanie W.; Joyner, Patrick W.; Almekinders, Louis C.; Parekh, Selene G.

2014-01-01

Context: Stress fractures of the foot and ankle are a common problem encountered by athletes of all levels and ages. These injuries can be difficult to diagnose and may be initially evaluated by all levels of medical personnel. Clinical suspicion should be raised with certain history and physical examination findings. Evidence Acquisition: Scientific and review articles were searched through PubMed (1930-2012) with search terms including stress fractures and 1 of the following: foot ankle, medial malleolus, lateral malleolus, calcaneus, talus, metatarsal, cuboid, cuneiform, sesamoid, or athlete. Study Design: Clinical review. Level of Evidence: Level 5. Results: Stress fractures of the foot and ankle can be divided into low and high risk based upon their propensity to heal without complication. A wide variety of nonoperative strategies are employed based on the duration of symptoms, type of fracture, and patient factors, such as activity type, desire to return to sport, and compliance. Operative management has proven superior in several high-risk types of stress fractures. Evidence on pharmacotherapy and physiologic therapy such as bone stimulators is evolving. Conclusion: A high index of suspicion for stress fractures is appropriate in many high-risk groups of athletes with lower extremity pain. Proper and timely work-up and treatment is successful in returning these athletes to sport in many cases. Low-risk stress fracture generally requires only activity modification while high-risk stress fracture necessitates more aggressive intervention. The specific treatment of these injuries varies with the location of the stress fracture and the goals of the patient. PMID:25364480

Organizational Stress as Moderator of Relationship Between Mental Health Provider Adaptability and Organizational Commitment.

PubMed

Green, Amy E; Dishop, Christopher R; Aarons, Gregory A

2016-10-01

Community mental health providers often operate within stressful work environments and are at high risk of emotional exhaustion, which can negatively affect job performance and client satisfaction with services. This cross-sectional study examined the relationships between organizational stress, provider adaptability, and organizational commitment. Variables were analyzed with moderated multilevel regression in a sample of 311 mental health providers from 49 community mental health programs. Stressful organizational climate, characterized by high levels of emotional exhaustion, role conflict, and role overload, was negatively related to organizational commitment. Organizational stress moderated the relationship between provider adaptability and organizational commitment, such that those who were more adaptable had greater levels of organizational commitment when organizational stress was low but were less committed than those who were less adaptable when organizational stress was high. Providers higher in adaptability may perceive their organization as a greater fit when the work environment is less stressful; however, highly adaptable providers may also exercise choice that manifests in lower commitment to staying in an overly stressful work environment. Service systems and organizational contexts are becoming increasingly demanding and stressful for direct mental health service providers. Therefore, community mental health organizations should assess and understand their organizational climate and intervene with empirically based organizational strategies when necessary to reduce stressful climates and maintain adaptable employees.

WIND TURBINES CAUSE CHRONIC STRESS IN BADGERS (MELES MELES) IN GREAT BRITAIN.

PubMed

Agnew, Roseanna C N; Smith, Valerie J; Fowkes, Robert C

2016-07-01

A paucity of data exists with which to assess the effects of wind turbines noise on terrestrial wildlife, despite growing concern about the impact of infrasound from wind farms on human health and well-being. In 2013, we assessed whether the presence of turbines in Great Britain impacted the stress levels of badgers ( Meles meles ) in nearby setts. Hair cortisol levels were used to determine if the badgers were physiologically stressed. Hair of badgers living <1 km from a wind farm had a 264% higher cortisol level than badgers >10 km from a wind farm. This demonstrates that affected badgers suffer from enhanced hypothalamo-pituitary-adrenal activity and are physiologically stressed. No differences were found between the cortisol levels of badgers living near wind farms operational since 2009 and 2012, indicating that the animals do not become habituated to turbine disturbance. Cortisol levels in the affected badgers did not vary in relation to the distance from turbines within 1 km, wind farm annual power output, or number of turbines. We suggest that the higher cortisol levels in affected badgers is caused by the turbines' sound and that these high levels may affect badgers' immune systems, which could result in increased risk of infection and disease in the badger population.

A Comparison of Zero-Profile Devices and Artificial Cervical Disks in Patients With 2 Noncontiguous Levels of Cervical Spondylosis.

PubMed

Qizhi, Sun; Lei, Sun; Peijia, Li; Hanping, Zhao; Hongwei, Hu; Junsheng, Chen; Jianmin, Li

2016-03-01

A prospective randomized and controlled study of 30 patients with 2 noncontiguous levels of cervical spondylosis. To compare the clinical outcome between zero-profile devices and artificial cervical disks for noncontiguous cervical spondylosis. Noncontiguous cervical spondylosis is an especial degenerative disease of the cervical spine. Some controversy exists over the choice of surgical procedure and fusion levels for it because of the viewpoint that the stress at levels adjacent to a fusion mass will increase. The increased stress will lead to the adjacent segment degeneration (ASD). According to the viewpoint, the intermediate segment will bear more stress after both superior and inferior segments' fusion. Cervical disk arthroplasty is an alternative to fusion because of its motion-preserving. Few comparative studies have been conducted on arthrodesis with zero-prolife devices and arthroplasty with artificial cervical disks for noncontiguous cervical spondylosis. Thirty patients with 2 noncontiguous levels of cervical spondylosis were enrolled and assigned to either group A (receiving arthroplasty using artificial cervical disks) and group Z (receiving arthrodesis using zero-profile devices). The clinical outcomes were assessed by the mean operative time, blood loss, Japanese Orthopedic Association (JOA) score, Neck Dysfunction Index (NDI), cervical lordosis, fusion rate, and complications. The mean follow-up was 32.4 months. There were no significant differences between the 2 groups in the blood loss, JOA score, NDI score, and cervical lordosis except operative time. The mean operative time of group A was shorter than that of group Z. Both the 2 groups demonstrated a significant increase in JOA score, NDI score, and cervical lordosis. The fusion rate was 100% at 12 months postoperatively in group Z. There was no significant difference between the 2 groups in complications except the ASD. Three patients had radiologic ASD at the final follow-up in group Z, and none in group A. Both zero-prolife devices and artificial cervical disks are generally effective and safe in the treatment of 2 noncontiguous levels of cervical spondylosis. However, in view of occurrence of the radiologic ASD and operative time, we prefer to artificial cervical disks if indications are well controlled.

DinB Upregulation Is the Sole Role of the SOS Response in Stress-Induced Mutagenesis in Escherichia coli

PubMed Central

Galhardo, Rodrigo S.; Do, Robert; Yamada, Masami; Friedberg, Errol C.; Hastings, P. J.; Nohmi, Takehiko; Rosenberg, Susan M.

2009-01-01

Stress-induced mutagenesis is a collection of mechanisms observed in bacterial, yeast, and human cells in which adverse conditions provoke mutagenesis, often under the control of stress responses. Control of mutagenesis by stress responses may accelerate evolution specifically when cells are maladapted to their environments, i.e., are stressed. It is therefore important to understand how stress responses increase mutagenesis. In the Escherichia coli Lac assay, stress-induced point mutagenesis requires induction of at least two stress responses: the RpoS-controlled general/starvation stress response and the SOS DNA-damage response, both of which upregulate DinB error-prone DNA polymerase, among other genes required for Lac mutagenesis. We show that upregulation of DinB is the only aspect of the SOS response needed for stress-induced mutagenesis. We constructed two dinB(oc) (operator-constitutive) mutants. Both produce SOS-induced levels of DinB constitutively. We find that both dinB(oc) alleles fully suppress the phenotype of constitutively SOS-“off” lexA(Ind−) mutant cells, restoring normal levels of stress-induced mutagenesis. Thus, dinB is the only SOS gene required at induced levels for stress-induced point mutagenesis. Furthermore, although spontaneous SOS induction has been observed to occur in only a small fraction of cells, upregulation of dinB by the dinB(oc) alleles in all cells does not promote a further increase in mutagenesis, implying that SOS induction of DinB, although necessary, is insufficient to differentiate cells into a hypermutable condition. PMID:19270270

The influence of percutaneous nephrolithotomy on human systemic stress response, SIRS and renal function.

PubMed

Shen, Pengfei; Wei, Wuran; Yang, Xiaochun; Zeng, Hao; Li, Xiong; Yang, Jie; Wang, Jia; Huang, Jiaoti

2010-10-01

The objective of this study is to investigate the influences of percutaneous nephrolithotomy (PNL) and open surgery nephrolithotomy on the systemic stress response, SIRS and renal function. Forty patients with kidney calculi were enrolled in the study. Twenty cases were randomized to the PNL group and the other twenty cases to the open surgery group. Levels of C-reactive protein (CRP), interleukin-6(IL-6), β(2)-microglobulin (β(2)-MG), respiration rate, heart rate, body temperature and white blood cell counts were examined. CRP and IL-6 were measured in all patients pre-operatively and on post-operative days 1, 3 and 6, respectively. There was significant difference in their pre- and post-operation levels (P < 0.05), with the peak of CRP and IL-6 observed at post-operative days 3 and 1, respectively. There was significant difference in both CRP and IL-6 between the two groups (P < 0.05). At post-operative day 1, there were 5 cases of SIRS in PNL group and 12 cases in open surgery group; there was significant difference between the two groups (P < 0.05). Serum β(2)-MG levels were measured as the same time as CRP and no significant changes were observed within or between the groups (P > 0.05). Urine β(2)-MG levels were also measured. There was significant difference between pre- and the first day post-PNL (P < 0.05); there was no significant difference between pre- and the third and sixth day post-PNL (P > 0.05). There was significant difference between pre- and first and third day post-open surgery (P < 0.05); but there was no significant difference between pre- and the sixth day post-open surgery (P > 0.05). There was significant difference between two groups at the first, third and sixth days (P < 0.05). The systemic stress response is activated both in PNL group and open surgery group to some extent. The degree of stress response of PNL is lower than that of open surgery, proving the advantages of PNL with reference to serum immunology. There were cases in both the groups with SIRS, but the degree of SIRS in PNL group was lesser than the other group. Both the groups have no obvious effect on glomerular filtration function after operation and have effect on renal tubular reabsorption in the early stage after operation; but the recovery of the PNL group is faster than the open surgery group. It is thus shown that PNL is much safer and more feasible and has lesser effect on renal function.

Serial perioperative cell-free DNA levels in donors and recipients undergoing living donor liver transplantation.

PubMed

Prakash, K; Aggarwal, S; Bhardwaj, S; Ramakrishna, G; Pandey, C K

2017-10-01

Effect of anaesthesia and surgery on cell-free DNA (cfDNA) is not known. Given that surgical stress augments inflammation and injury, we hypothesized that levels of cfDNA will fluctuate during perioperative period. Therefore, in this study serial perioperative cfDNA concentration was measured in donors and recipients undergoing living donor liver transplantation (LDLT). Baseline, post-induction, intraoperative and post-operative plasma cfDNA levels were evaluated in 21 donors and recipients each, by Sytox green method. In addition, qPCR was performed in a subset of samples. Baseline cfDNA levels were higher in recipients (37.62 ng/ml) than in donors (25.49 ng/ml). A decrease in cfDNA was observed following anaesthesia induction in both recipients (11.90 ng/ml) and donors (10.75 ng/ml). When the kinetics of the cfDNA was monitored further, an increase was noted intraoperatively in donors (46.18 ng/ml) and recipients (anhepatic phase: 56.25 ng/ml, reperfusion phase: 54.36 ng/ml). cfDNA levels remained high post-operatively. One recipient who developed post-operative sepsis had the highest cfDNA level (94.72 ng/ml). Plasma cfDNA levels are high in recipients indicative of liver injury. Lower cfDNA levels following induction may be attributed to the subduing effect of anaesthetic agents on cell death. High cfDNA levels seen in intra- and post-operative phases reflect cellular trauma and inflammation. This similar pattern of fluctuation of cfDNA level in donors and recipients is suggestive of its possible utility as a surgical stress marker. In addition, comparable cfDNA levels in anhepatic and reperfusion phase reflect less ischemia reperfusion injury during LDLT. © 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Crystallographic texture in oxide-dispersion-strengthened alloys

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.

1982-01-01

Crystallographic and elastic moduli data are presented which document the degree of texture in several oxide dispersion-strengthened (ODS) nickel-base alloys. The existence of strong crystallographic textures in such multicrystalline alloys is considered important, since the small angle grain boundaries may be partially responsible for creep threshold stresses. Gleiter (1979) has shown that ideal, low energy boundaries will act as vacancy sources only when the applied stress is greater than a threshold stress, while large angle grain boundaries will emit vacancies at all stress levels. The continued operation of a net vacancy in an ODS alloy must be avoided, since it will lead to a localized disruption of the microstructure.

Local Directors of School Education in Greece: Their Role and Main Sources of Job Stress

ERIC Educational Resources Information Center

Lainas, Athanassios

2010-01-01

Directors of education in Greece operate at prefectural level and are the heads of the local directorates or bureaus of primary/secondary education. Because of the centralized character of the educational system, their role is restricted to facilitating the smooth operation of the local school system and implementing the national policy on school…

Parametric study of irradiation effects on the ductile damage and flow stress behavior in ferritic-martensitic steels

NASA Astrophysics Data System (ADS)

Chakraborty, Pritam; Biner, S. Bulent

2015-10-01

Ferritic-martensitic steels are currently being considered as structural materials in fusion and Gen-IV nuclear reactors. These materials are expected to experience high dose radiation, which can increase their ductile to brittle transition temperature and susceptibility to failure during operation. Hence, to estimate the safe operational life of the reactors, precise evaluation of the ductile to brittle transition temperatures of ferritic-martensitic steels is necessary. Owing to the scarcity of irradiated samples, particularly at high dose levels, micro-mechanistic models are being employed to predict the shifts in the ductile to brittle transition temperatures. These models consider the ductile damage evolution, in the form of nucleation, growth and coalescence of voids; and the brittle fracture, in the form of probabilistic cleavage initiation, to estimate the influence of irradiation on the ductile to brittle transition temperature. However, the assessment of irradiation dependent material parameters is challenging and influences the accuracy of these models. In the present study, the effects of irradiation on the overall flow stress and ductile damage behavior of two ferritic-martensitic steels is parametrically investigated. The results indicate that the ductile damage model parameters are mostly insensitive to irradiation levels at higher dose levels though the resulting flow stress behavior varies significantly.

Effect of oxidative stress induced by intracranial iron overload on central pain after spinal cord injury.

PubMed

Meng, Fan Xing; Hou, Jing Ming; Sun, Tian Sheng

2017-02-08

Central pain (CP) is a common clinical problem in patients with spinal cord injury (SCI). Recent studies found the pathogenesis of CP was related to the remodeling of the brain. We investigate the roles of iron overload and subsequent oxidative stress in the remodeling of the brain after SCI. We established a rat model of central pain after SCI. Rats were divided randomly into four groups: SCI, sham operation, SCI plus deferoxamine (DFX) intervention, and SCI plus nitric oxide synthase (NOS) inhibitor treatment. Pain behavior was observed and thermal pain threshold was measured regularly, and brain levels of iron, transferrin receptor 1 (TfR1), ferritin (Fn), and lactoferrin (Lf), were detected in the different groups 12 weeks after establishment of the model. Rats demonstrated self-biting behavior after SCI. Furthermore, the latent period of thermal pain was reduced and iron levels in the hind limb sensory area, hippocampus, and thalamus increased after SCI. Iron-regulatory protein (IRP) 1 levels increased in the hind limb sensory area, while Fn levels decreased. TfR1 mRNA levels were also increased and oxidative stress was activated. Oxidative stress could be inhibited by ferric iron chelators and NOS inhibitors. SCI may cause intracranial iron overload through the NOS-iron-responsive element/IRP pathway, resulting in central pain mediated by the oxidative stress response. Iron chelators and oxidative stress inhibitors can effectively relieve SCI-associated central pain.

Post-Traumatic Stress Disorder Among Health Care Providers Following the Israeli Attacks Against Gaza Strip in 2014: A Call for Immediate Policy Actions.

PubMed

Abu-El-Noor, Nasser Ibrahim; Aljeesh, Yousef Ibrahim; Radwan, AbdalKarim Said; Abu-El-Noor, Mysoon Khalil; Qddura, Ibrahim Abdel-Ilhady; Khadoura, Khalid Jamal; Alnawajha, Samer Khader

2016-04-01

This study aimed to assess the level of posttraumatic stress disorder and to examine the relationship between exposure to war stress and posttraumatic symptoms among health care providers following Israeli offensives against Gaza Strip in 2014. A cross-sectional design was used for this study. We targeted all nurses and doctors working in three governmental hospitals in the Gaza Strip and worked with victims of the last war, more specifically, those who were working in emergency departments, intensive care units, operating rooms, surgical departments, and burn units. A demographic sheet and Impact Event Scale-Revised were used in this study. The Impact Event Scale-Revised has three sub-scales; intrusion, avoidance, and hyper-arousal. The results showed that 291 (89.8%) of 324 participants had scores more than 35 (threshold cut-off point) on the Impact Event Scale-Revised. Scores ranged from zero to 80 with a mean of 52.13. Females had higher levels of stress (55.79) than males (51.63) and nurses (54.85) had more stress than physicians (47.38). The most frequent symptoms of trauma subscales was "avoidance" (mean=20.04), followed by "intrusion" (mean=17.83), and then "hyper-arousal" (mean=14.27). Levels of trauma symptoms were not affected by place of living, hospital of work, while level of education had impacted level of trauma. The findings showed that health care providers suffered from severe posttraumatic symptoms after exposure to prolonged war stress. This level of trauma among health care providers warrants intervention programs to reduce stress and trauma among Gaza health care providers after the war. Copyright © 2015 Elsevier Inc. All rights reserved.

The impact of heat stress on operative performance and cognitive function during simulated laparoscopic operative tasks.

PubMed

Berg, Regan J; Inaba, Kenji; Sullivan, Maura; Okoye, Obi; Siboni, Stefano; Minneti, Michael; Teixeira, Pedro G; Demetriades, Demetrios

2015-01-01

Increasing ambient temperature to prevent intraoperative patient hypothermia remains widely advocated despite unconvincing evidence of efficacy. Heat stress is associated with decreased cognitive and psychomotor performance across multiple tasks but remains unexamined in an operative context. We assessed the impact of increased ambient temperature on laparoscopic operative performance and surgeon cognitive stress. Forty-two performance measures were obtained from 21 surgery trainees participating in the counter-balanced, within-subjects study protocol. Operative performance was evaluated with adaptations of the validated, peg-transfer, and intracorporeal knot-tying tasks from the Fundamentals of Laparoscopic Surgery program. Participants trained to proficiency before enrollment. Task performance was measured at two ambient temperatures, 19 and 26°C (66 and 79°F). Participants were randomly counterbalanced to initial hot or cold exposure before crossing over to the alternate environment. Cognitive stress was measured using the validated Surgical Task Load Index (SURG-TLX). No differences in performance of the peg-transfer and intracorporeal knot-tying tasks were seen across ambient conditions. Assessed via use of the six bipolar scales of the SURG-TLX, we found differences in task workload between the hot and cold conditions in the areas of physical demands (hot 10 [3-12], cold 5 [2.5-9], P = .013) and distractions (hot 8 [3.5-15.5], cold 3 [1.5-5.5], P = .001). Participant perception of distraction remained greater in the hot condition on full scoring of the SURG-TLX. Increasing ambient temperature to levels advocated for prevention of intraoperative hypothermia does not greatly decrease technical performance in short operative tasks. Surgeons, however, do report increased perceptions of distraction and physical demand. The impact of these findings on performance and outcomes during longer operative procedures remains unclear. Copyright © 2015 Elsevier Inc. All rights reserved.

Stress fractures of the foot and ankle in athletes.

PubMed

Mayer, Stephanie W; Joyner, Patrick W; Almekinders, Louis C; Parekh, Selene G

2014-11-01

Stress fractures of the foot and ankle are a common problem encountered by athletes of all levels and ages. These injuries can be difficult to diagnose and may be initially evaluated by all levels of medical personnel. Clinical suspicion should be raised with certain history and physical examination findings. Scientific and review articles were searched through PubMed (1930-2012) with search terms including stress fractures and 1 of the following: foot ankle, medial malleolus, lateral malleolus, calcaneus, talus, metatarsal, cuboid, cuneiform, sesamoid, or athlete. Clinical review. Level 5. Stress fractures of the foot and ankle can be divided into low and high risk based upon their propensity to heal without complication. A wide variety of nonoperative strategies are employed based on the duration of symptoms, type of fracture, and patient factors, such as activity type, desire to return to sport, and compliance. Operative management has proven superior in several high-risk types of stress fractures. Evidence on pharmacotherapy and physiologic therapy such as bone stimulators is evolving. A high index of suspicion for stress fractures is appropriate in many high-risk groups of athletes with lower extremity pain. Proper and timely work-up and treatment is successful in returning these athletes to sport in many cases. Low-risk stress fracture generally requires only activity modification while high-risk stress fracture necessitates more aggressive intervention. The specific treatment of these injuries varies with the location of the stress fracture and the goals of the patient.

Analysis tool and methodology design for electronic vibration stress understanding and prediction

NASA Astrophysics Data System (ADS)

Hsieh, Sheng-Jen; Crane, Robert L.; Sathish, Shamachary

2005-03-01

The objectives of this research were to (1) understand the impact of vibration on electronic components under ultrasound excitation; (2) model the thermal profile presented under vibration stress; and (3) predict stress level given a thermal profile of an electronic component. Research tasks included: (1) retrofit of current ultrasonic/infrared nondestructive testing system with sensory devices for temperature readings; (2) design of software tool to process images acquired from the ultrasonic/infrared system; (3) developing hypotheses and conducting experiments; and (4) modeling and evaluation of electronic vibration stress levels using a neural network model. Results suggest that (1) an ultrasonic/infrared system can be used to mimic short burst high vibration loads for electronics components; (2) temperature readings for electronic components under vibration stress are consistent and repeatable; (3) as stress load and excitation time increase, temperature differences also increase; (4) components that are subjected to a relatively high pre-stress load, followed by a normal operating load, have a higher heating rate and lower cooling rate. These findings are based on grayscale changes in images captured during experimentation. Discriminating variables and a neural network model were designed to predict stress levels given temperature and/or grayscale readings. Preliminary results suggest a 15.3% error when using grayscale change rate and 12.8% error when using average heating rate within the neural network model. Data were obtained from a high stress point (the corner) of the chip.

Intersection of Stress, Social Disadvantage, and Life Course Processes: Reframing Trauma and Mental Health.

PubMed

Nurius, Paula S; Uehara, Edwina; Zatzick, Douglas F

2013-04-01

This paper describes the intersection of converging lines of research on the social structural, psychosocial, and physiological factors involved in the production of stress and implications for the field of mental health. Of particular interest are the stress sensitization consequences stemming from exposure to adversity over the life course. Contemporary stress sensitization theory provides important clinical utility in articulating mechanisms through which these multiple levels exert influence on mental health. Stress sensitization models (a) extend understanding of neurobiological and functional contexts within which extreme stressors operate and (b) make clear how these can influence psychologically traumatic outcomes. The value of interventions that are sensitive to current contexts as well as life course profiles of cumulative stress are illustrated through recent treatment innovations.

Intersection of Stress, Social Disadvantage, and Life Course Processes: Reframing Trauma and Mental Health

PubMed Central

Nurius, Paula S.; Uehara, Edwina; Zatzick, Douglas F.

2015-01-01

This paper describes the intersection of converging lines of research on the social structural, psychosocial, and physiological factors involved in the production of stress and implications for the field of mental health. Of particular interest are the stress sensitization consequences stemming from exposure to adversity over the life course. Contemporary stress sensitization theory provides important clinical utility in articulating mechanisms through which these multiple levels exert influence on mental health. Stress sensitization models (a) extend understanding of neurobiological and functional contexts within which extreme stressors operate and (b) make clear how these can influence psychologically traumatic outcomes. The value of interventions that are sensitive to current contexts as well as life course profiles of cumulative stress are illustrated through recent treatment innovations. PMID:25729337

Randomized clinical trial to evaluate mental practice in enhancing advanced laparoscopic surgical performance.

PubMed

Louridas, M; Bonrath, E M; Sinclair, D A; Dedy, N J; Grantcharov, T P

2015-01-01

Mental practice, the cognitive rehearsal of a task without physical movement, is known to enhance performance in sports and music. Investigation of this technique in surgery has been limited to basic operations. The purpose of this study was to develop mental practice scripts, and to assess their effect on advanced laparoscopic skills and surgeon stress levels in a crisis scenario. Twenty senior surgical trainees were randomized to either conventional training or mental practice groups, the latter being trained by an expert performance psychologist. Participants' skills were assessed while performing a porcine laparoscopic jejunojejunostomy as part of a crisis scenario in a simulated operating room, using the Objective Structured Assessment of Technical Skill (OSATS) and bariatric OSATS (BOSATS) instruments. Objective and subjective stress parameters were measured, as well as non-technical skills using the Non-Technical Skills for Surgeons rating tool. An improvement in OSATS (P = 0.003) and BOSATS (P = 0.003) scores was seen in the mental practice group compared with the conventional training group. Seven of ten trainees improved their technical performance during the crisis scenario, whereas four of the ten conventionally trained participants deteriorated. Mental imagery ability improved significantly following mental practice training (P = 0.011), but not in the conventional group (P = 0.083). No differences in objective or subjective stress levels or non-technical skills were evident. Mental practice improves technical performance for advanced laparoscopic tasks in the simulated operating room, and allows trainees to maintain or improve their performance despite added stress. © 2014 BJS Society Ltd. Published by John Wiley & Sons Ltd.

Composite Overwrapped Pressure Vessels (COPV) Stress Rupture Test: Part 2. Part 2

NASA Technical Reports Server (NTRS)

Russell, Richard; Flynn, Howard; Forth, Scott; Greene, Nathanael; Kezirian, Michael; Varanauski, Don; Leifeste, Mark; Yoder, Tommy; Woodworth, Warren

2010-01-01

One of the major concerns for the aging Space Shuttle fleet is the stress rupture life of composite overwrapped pressure vessels (COPVs). Stress rupture life of a COPY has been defined as the minimum time during which the composite maintains structural integrity considering the combined effects of stress levels and time. To assist in the evaluation of the aging COPVs in the Orbiter fleet an analytical reliability model was developed. The actual data used to construct this model was from testing of COPVs constructed of similar, but not exactly same materials and pressure cycles as used on Orbiter vessels. Since no actual Orbiter COPV stress rupture data exists the Space Shuttle Program decided to run a stress rupture test to compare to model predictions. Due to availability of spares, the testing was unfortunately limited to one 40" vessel. The stress rupture test was performed at maximum operating pressure at an elevated temperature to accelerate aging. The test was performed in two phases. The first phase, 130 F, a moderately accelerated test designed to achieve the midpoint of the model predicted point reliability. A more aggressive second phase, performed at 160 F, was designed to determine if the test article will exceed the 95% confidence interval ofthe model. In phase 3, the vessel pressure was increased to above maximum operating pressure while maintaining the phase 2 temperature. After reaching enough effectives hours to reach the 99.99% confidence level of the model phase 4 testing began when the temperature was increased to greater than 170 F. The vessel was maintained at phase 4 conditions until it failed after over 3 million effect hours. This paper will discuss the results of this test, it's implications and possible follow-on testing.

Stress generation in a developmental context: the role of youth depressive symptoms, maternal depression, the parent-child relationship, and family stress.

PubMed

Chan, Priscilla T; Doan, Stacey N; Tompson, Martha C

2014-02-01

The present study examined stress generation in a developmental and family context among 171 mothers and their preadolescent children, ages 8-12 years, at baseline (Time 1) and 1-year follow-up (Time 2). In the current study, we examined the bidirectional relationship between children's depressive symptoms and dependent family stress. Results suggest that children's baseline level of depressive symptoms predicted the generation of dependent family stress 1 year later. However, baseline dependent family stress did not predict an increase in children's depressive symptoms 1 year later. In addition, we examined whether a larger context of both child chronic strain (indicated by academic, behavioral, and peer stress) and family factors, including socioeconomic status and parent-child relationship quality, would influence the stress generation process. Although both chronic strain and socioeconomic status were not associated with dependent family stress at Time 2, poorer parent-child relationship quality significantly predicted greater dependent family stress at Time 2. Child chronic strain, but neither socioeconomic status nor parent-child relationship quality, predicted children's depression symptoms at Time 2. Finally, gender, maternal depression history, and current maternal depressive symptoms did not moderate the relationship between level of dependent family stress and depressive symptoms. Overall, findings provide partial support for a developmental stress generation model operating in the preadolescent period.

Psychological resilience after Hurricane Sandy: the influence of individual- and community-level factors on mental health after a large-scale natural disaster.

PubMed

Lowe, Sarah R; Sampson, Laura; Gruebner, Oliver; Galea, Sandro

2015-01-01

Several individual-level factors are known to promote psychological resilience in the aftermath of disasters. Far less is known about the role of community-level factors in shaping postdisaster mental health. The purpose of this study was to explore the influence of both individual- and community-level factors on resilience after Hurricane Sandy. A representative sample of household residents (N = 418) from 293 New York City census tracts that were most heavily affected by the storm completed telephone interviews approximately 13-16 months postdisaster. Multilevel multivariable models explored the independent and interactive contributions of individual- and community-level factors to posttraumatic stress and depression symptoms. At the individual-level, having experienced or witnessed any lifetime traumatic event was significantly associated with higher depression and posttraumatic stress, whereas demographic characteristics (e.g., older age, non-Hispanic Black race) and more disaster-related stressors were significantly associated with higher posttraumatic stress only. At the community-level, living in an area with higher social capital was significantly associated with higher posttraumatic stress. Additionally, higher community economic development was associated with lower risk of depression only among participants who did not experience any disaster-related stressors. These results provide evidence that individual- and community-level resources and exposure operate in tandem to shape postdisaster resilience.

Role of free radicals in aseptic loosening of hip arthroplasty.

PubMed

Kinov, Plamen; Leithner, Andreas; Radl, Roman; Bodo, Koppany; Khoschsorur, Gholam-Ali; Schauenstein, Konrad; Windhager, Reinhard

2006-01-01

Fibrous pseudocapsule around hip implants is an invariable finding at revision operations and is believed to release inflammatory mediators that stimulate bone resorption. Reactive oxygen species have been proposed to be causative factors in various disorders with tissue fibrosis. We were interested in investigating whether aseptic loosening is connected with high oxidative stress, and in showing the underlying mechanism of periprosthetic fibrosis and its role in loosening. Levels of oxidative stress markers reduced (GSH) and oxidized (GSSG) gluthatione and malondialdehyde (MDA) were assayed in 28 loose hips and in 12 stable hips revised for high rate of wear and osteolysis. Collagen in the periprosthetic tissues was measured as hydroxyproline content. Osteolysis and polyethylene wear were graded. Increased oxidative stress measured by low GSH/GSSG ratio as well as by increased MDA level was established in patients compared to controls. Oxidative stress markers intercorrelated significantly. MDA and both GSH and GSSG levels correlated significantly with hydroxyproline level. Levels of GSSG and MDA were higher in hips with greater polyethylene wear. The results suggest that high oxidative stress may play a role in formation of a fibrous membrane observed at revision of loose hips. The fibrous pseudocapsule is probably related to high intraarticular pressure and expansion of the effective joint space. This study may elicit some aspects of the pathogenesis of aseptic hip loosening and aid in future investigations aiming at prevention of this complication.

Low-pressure capnoperitoneum reduces stress responses during pediatric laparoscopic high ligation of indirect inguinal hernia sac: A randomized controlled study.

PubMed

Niu, Xiaoguang; Song, Xubin; Su, Aiping; Zhao, Shanshan; Li, Qinghao

2017-04-01

We aimed to evaluate the effect of different capnoperitoneum pressures on stress responses in pediatric laparoscopic inguinal hernia repair. In this prospective randomized controlled study, 68 children with indirect inguinal hernia who underwent high ligation of hernia sac were randomly divided into 3 groups: high-pressure group (12 mm Hg, HP group, n = 26); low-pressure group (8 mm Hg, LP group, n = 20); open operation group (OP group, n = 22). Heart rate (HR), blood pressure, and end-tidal CO2 (PetCO2) were recorded, as well as the levels of adrenocorticotropic hormone (ACTH) and cortisol (COR) were measured by ELISAs before operation, during operation, and after operation, respectively. After establishing capnoperitoneum, HR, blood pressure, and PetCO2 were significantly increased in the HP group compared with the OP and LP groups (P < 0.05). Comparing the intraoperatively measured ACTH and COR concentrations of the HP group to the LP group, we noted higher values in the first (P < 0.05). There was no significant difference in the postoperative concentrations of ACTH and COR among the HP, LP, and OP groups. Laparoscopic surgery under LP capnoperitoneum or open operation may reduce stress responses and are superior to HP capnoperitoneum.

UOE Pipe Manufacturing Process Simulation: Equipment Designing and Construction

NASA Astrophysics Data System (ADS)

Delistoian, Dmitri; Chirchor, Mihael

2017-12-01

UOE pipe manufacturing process influence directly on pipeline resilience and operation capacity. At present most spreaded pipe manufacturing method is UOE. This method is based on cold forming. After each technological step appears a certain stress and strain level. For pipe stress strain study is designed and constructed special equipment that simulate entire technological process.UOE pipe equipment is dedicated for manufacturing of longitudinally submerged arc welded DN 400 (16 inch) steel pipe.

Increased activity of osteocyte autophagy in ovariectomized rats and its correlation with oxidative stress status and bone loss

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

Yang, Yuehua, E-mail: yuesjtu@126.com; Zheng, Xinfeng, E-mail: zxf272@126.com; Li, Bo, E-mail: libo@126.com

Highlights: • Examine autophagy level in the proximal tibia of ovariectomized rats. • Investigate whether autophagy level is associated with bone loss. • Investigate whether autophagy level is associated with oxidative stress status. - Abstract: Objectives: The objectives of the present study were to investigate ovariectomy on autophagy level in the bone and to examine whether autophagy level is associated with bone loss and oxidative stress status. Methods: 36 female Sprague–Dawley rats were randomly divided into sham-operated (Sham), and ovariectomized (OVX) rats treated either with vehicle or 17-β-estradiol. At the end of the six-week treatment, bone mineral density (BMD) andmore » bone micro-architecture in proximal tibias were assessed by micro-CT. Serum 17β-estradiol (E2) level were measured. Total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity, catalase (CAT) activity in proximal tibia was also determined. The osteocyte autophagy in proximal tibias was detected respectively by Transmission Electron Microscopy (TEM), immunofluorescent histochemistry (IH), realtime-PCR and Western blot. In addition, the spearman correlation between bone mass, oxidative stress status, serum E2 and autophagy were analyzed. Results: Ovariectomy increased Atg5, LC3, and Beclin1 mRNA and proteins expressions while decreased p62 expression. Ovariectomy also declined the activities of T-AOC, CAT, and SOD. Treatment with E2 prevented the reduction in bone mass as well as restored the autophagy level. Furthermore, LC3-II expression was inversely correlated with T-AOC, CAT, and SOD activities. A significant inverse correlation between LC3-II expression and BV/TV, Tb.N, BMD in proximal tibias was found. Conclusions: Ovariectomy induced oxidative stress, autophagy and bone loss. Autophagy of osteocyte was inversely correlated with oxidative stress status and bone loss.« less

Manufacturing and test of 2G-HTS coils for rotating machines: Challenges, conductor requirements, realization

NASA Astrophysics Data System (ADS)

Oomen, Marijn; Herkert, Werner; Bayer, Dietmar; Kummeth, Peter; Nick, Wolfgang; Arndt, Tabea

2012-11-01

We investigate the use of 2nd-generation High-Temperature Superconductors (2G-HTSs) in the rotors of electrical motors and generators. For these devices the conductor must be wound into robust impregnated coils, which are operated in vacuum at temperatures around 30 K, in strong magnetic fields of about 2T. Differences in thermal contraction between the coil former, conductor constituents, impregnation resin, bandage and heat-sink materials (assembled at room temperature) cause mechanical stresses at operating temperature. Rotating-machine operation adds Lorentz forces and challenging centripetal accelerations up to thousands of g. Second generation-HTS conductors withstand large tensile stresses in axial direction and compression in normal direction. However, shear stresses, axial compression, and tension normal to the conductor can cause degradation in superconducting properties. Such stresses can be mitigated by correct choice of materials, coil lay-out and manufacturing process. A certain stress level will remain, which the conductor must withstand. We have manufactured many impregnated round and race-track coils, using different 2G-HTS conductors, and tested them at temperatures from 25 K to 77 K. Degradation of the superconductor in early coils was traced to the mentioned differences in thermal contraction, and was completely avoided in coils produced later. We will discuss appropriate coil-winding techniques to assure robust and reliable superconductor performance.

Occupational stress, anxiety and coping strategies in police officers.

PubMed

Acquadro Maran, D; Varetto, A; Zedda, M; Ieraci, V

2015-08-01

Studies on occupational stress have shown that police officers are exposed to stressful events more often than other workers and this can result in impaired psychosocial well-being and physical health. To measure the level of stress experienced, the consequences in terms of anxiety and the coping strategies adopted in a sample of police officers working in a large city in northern Italy. We used the Police Stress Questionnaire and the Distress Thermometer to measure occupational stress, the State-Trait Anxiety Inventory to measure anxiety and the Brief COPE questionnaire to measure coping strategies. Six hundred seventeen police officers completed the questionnaire, a response rate of 34%. Differences between genders, sectors and roles emerged, but overall the study population generally demonstrated good use of positive coping strategies. Women in all operational service roles were more vulnerable to both organizational and operational stressors than men (P < 0.001), while in the interior department, men were more vulnerable to organizational stressors (P < 0.05). Our results suggest that for Italian police officers, training courses and support in dealing with occupational stress should take into account gender, role and type of work. Tailored training courses and support programmes could be useful and effective tools for preventing stress before it becomes chronic. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Stress in crisis managers: evidence from self-report and psychophysiological assessments.

PubMed

Janka, A; Adler, C; Fischer, L; Perakakis, P; Guerra, P; Duschek, S

2015-12-01

Directing disaster operations represents a major professional challenge. Despite its importance to health and professional performance, research on stress in crisis management remains scarce. The present study aimed to investigate self-reported stress and psychophysiological stress responses in crisis managers. For this purpose, 30 crisis managers were compared with 30 managers from other disciplines, in terms of self-reported stress, health status and psychophysiological reactivity to crisis-related and non-specific visual and acoustic aversive stimuli and cognitive challenge. Crisis managers reported lower stress levels, a more positive strain-recuperation-balance, greater social resources, reduced physical symptoms, as well as more physical exercise and less alcohol consumption. They exhibited diminished electrodermal and heart rate responses to crisis-related and non-specific stressors. The results indicate reduced stress and physical complaints, diminished psychophysiological stress reactivity, and a healthier life-style in crisis managers. Improved stress resistance may limit vulnerability to stress-related performance decline and facilitate preparedness for major incidents.

40 CFR 265.443 - Design and operating requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., climatic conditions, the stress of installation, and the stress of daily operations, e.g., variable and... pad leakage to which they are exposed, climatic conditions, the stress of installation, and the stress of daily operation (including stresses from vehicular traffic on the drip pad); (ii) Placed upon a...

40 CFR 265.443 - Design and operating requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., climatic conditions, the stress of installation, and the stress of daily operations, e.g., variable and... pad leakage to which they are exposed, climatic conditions, the stress of installation, and the stress of daily operation (including stresses from vehicular traffic on the drip pad); (ii) Placed upon a...

40 CFR 265.443 - Design and operating requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., climatic conditions, the stress of installation, and the stress of daily operations, e.g., variable and... pad leakage to which they are exposed, climatic conditions, the stress of installation, and the stress of daily operation (including stresses from vehicular traffic on the drip pad); (ii) Placed upon a...

Sex-reversed correlation between stress levels and dominance rank in a captive non-breeder flock of crows.

PubMed

Ode, Minami; Asaba, Akari; Miyazawa, Eri; Mogi, Kazutaka; Kikusui, Takefumi; Izawa, Ei-Ichi

2015-07-01

Group living has both benefits and costs to individuals; benefits include efficient acquisition of resources, and costs include stress from social conflicts among group members. Such social challenges result in hierarchical dominance ranking among group members as a solution to avoid escalating conflict that causes different levels of basal stress between individuals at different ranks. Stress-associated glucocorticoid (corticosterone in rodents and birds; CORT) levels are known to correlate with dominance rank in diverse taxa and to covary with various social factors, such as sex and dominance maintenance styles. Although there is much evidence for sex differences in the basal levels of CORT in various species, the correlation of sex differences in basal CORT with dominance rank is poorly understood. We investigated the correlation between CORT metabolites (CM) in the droppings and social factors, including rank and sex, in a captive non-breeder group of crows. In this group, all the single males dominated all the single females, and dominance ranks were stable among single males but relatively unstable among single females. CM levels and rank were significantly correlated in a sex-reversed fashion: males at higher rank (i.e., more dominant) had higher CM, whereas females at higher rank exhibited lower CM. This is the first evidence of sex-reversed patterns of CM-rank correlation in birds. The results suggest that different mechanisms of stress-dominance relationships operate on the sexes in non-breeder crow aggregations; in males, stress is associated with the cost of aggressive displays, whereas females experience subordination stress due to males' overt aggression. Copyright © 2015 Elsevier Inc. All rights reserved.

The effects of heat stress on morphological properties and intracellular signaling of denervated and intact soleus muscles in rats.

PubMed

Ohira, Takashi; Higashibata, Akira; Seki, Masaya; Kurata, Yoichi; Kimura, Yayoi; Hirano, Hisashi; Kusakari, Yoichiro; Minamisawa, Susumu; Kudo, Takashi; Takahashi, Satoru; Ohira, Yoshinobu; Furukawa, Satoshi

2017-08-01

The effects of heat stress on the morphological properties and intracellular signaling of innervated and denervated soleus muscles were investigated. Heat stress was applied to rats by immersing their hindlimbs in a warm water bath (42°C, 30 min/day, every other day following unilateral denervation) under anesthesia. During 14 days of experimental period, heat stress for a total of seven times promoted growth-related hypertrophy in sham-operated muscles and attenuated atrophy in denervated muscles. In denervated muscles, the transcription of ubiquitin ligase, atrogin-1/muscle atrophy F-box ( Atrogin-1 ), and muscle RING-finger protein-1 ( MuRF-1 ), genes was upregulated and ubiquitination of proteins was also increased. Intermittent heat stress inhibited the upregulation of Atrogin-1 , but not MuRF-1 transcription. And the denervation-caused reduction in phosphorylated protein kinase B (Akt), 70-kDa heat-shock protein (HSP70), and peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1 α ), which are negative regulators of Atrogin-1 and MuRF-1 transcription, was mitigated. In sham-operated muscles, repeated application of heat stress did not affect Atrogin-1 and MuRF-1 transcription, but increased the level of phosphorylated Akt and HSP70, but not PGC-1 α Furthermore, the phosphorylation of Akt and ribosomal protein S6, which is known to stimulate protein synthesis, was increased immediately after a single heat stress particularly in the sham-operated muscles. The effect of a heat stress was suppressed in denervated muscles. These results indicated that the beneficial effects of heat stress on the morphological properties of muscles were brought regardless of innervation. However, the responses of intracellular signaling to heat stress were distinct between the innervated and denervated muscles. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Effect of different stages of tensile deformation on micromagnetic parameters in high-strength, low-alloy steel

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

Vaidyanathan, S.; Moorthy, V.; Kalyanasundaram, P.

The influence of tensile deformation on the magnetic Barkhausen emissions (MBE) and hysteresis loop has been studied in a high-strength, low-alloy steel (HSLA) and its weldment. The magnetic measurements were made both in loaded and unloaded conditions for different stress levels. The root-mean-square (RMS) voltage of the MBE has been used for analysis. This study shows that the preyield and postyield deformation can be identified from the change in the MBE profile. The initial elastic deformation showed a linear increase in the MBE level in the loaded condition, and the MBE level remained constant in the unloaded condition. The microplasticmore » yielding, well below the macroyield stress, significantly reduces the MBE, indicating the operation of grain-boundary dislocation sources below the macroyield stress. This is indicated by the slow increase in the MBE level in the loaded condition and the decrease in the MBE level in the unloaded condition. The macroyielding resulted in a significant increase in the MBE level in the loaded condition and, more clearly, in the unloaded condition. The increase in the MBE level during macroyielding has been attributed to the grain rotation phenomenon, in order to maintain the boundary integrity between adjacent grains, which would preferentially align the magnetic domains along the stress direction. This study shows that MBE during tensile deformation can be classified into four stages: (1) perfectly elastic, (2) microplastic yielding, (3) macroyielding, and (4) progressive plastic deformation. A multimagnetic parameter approach, combining the hysteresis loop and MBE, has been suggested to evaluate the residual stresses.« less

The effect of prolonged exposure to war-related stress among hospital personnel with different affect types: lessons from the Second Lebanon War and the Gaza "Cast Lead" operation.

PubMed

Palgi, Yuval; Ben-Ezra, Menachem; Shrira, Amit

2012-01-01

Two studies examined peritraumatic symptoms due to war-related stress among hospital personnel with different affect types. In Study 1, we examined 80 Israeli hospital personnel during the period they were exposed to frequent missile attacks in the Second Lebanon War. In Study 2, we examined 67 and 74 Israeli hospital personnel during the time they were exposed and were not exposed, respectively, to missile attacks in the Gaza "Cast Lead" operation. In both studies, hospital personnel completed measures of posttraumatic stress disorder symptoms as well as of positive- and negative-affect items (PA and NA, respectively). Exposed personnel with a positive congruent (high PA and low NA) or a deflated incongruent (low PA and low NA) affective types had a lower level of peritraumatic symptoms compared to those with a negative congruent (low PA and high NA) or an inflated incongruent (high PA and NA) affective types. Study 2 further showed that among non-exposed personnel, only personnel with a negative congruent affective type had a higher level of peritraumatic symptoms compared to personnel with other affective types. Clinical implications and required future studies are discussed.

The combined effects of pyridostigmine and chronic stress on brain cortical and blood acetylcholinesterase, corticosterone, prolactin and alternation performance in rats.

PubMed

Kant, G J; Bauman, R A; Feaster, S R; Anderson, S M; Saviolakis, G A; Garcia, G E

2001-01-01

Thousands of soldiers who served in the Gulf War have symptoms that have been collectively termed Gulf War Illness (GWI). It has been suggested that a combination of operational stress and pyridostigmine, a drug given as a pretreatment to protect soldiers against the effects of exposure to nerve agents, might have had unexpected adverse health effects causing these symptoms. Our laboratory has previously modeled operational stress in rats using a paradigm of around-the-clock intermittent signalled footshock. In the present studies, this model was used to investigate the potential synergistic effects of chronic stress and pyridostigmine on physiology and behavior. Seventy-two rats were trained to perform an alternation lever pressing task to earn their entire daily food intake. The rats were then implanted with osmotic minipumps containing vehicle, pyridostigmine (25 mg/ml pyridostigmine bromide) or physostigmine (20 mg/ml eserine hemisulfate). The pumps delivered 1 microl/h, which resulted in a cumulative dosing of approximately 1.5 mg/kg/day of pyridostigmine or 1.2 mg/kg/day of physostigmine, equimolar doses of the two drugs. The rats were then returned to their home cages where performance continued to be measured 24 h/day. After 4 days, 24 of the 72 rats were trained to escape signalled footshock (avoidance-escape group) and 24 other rats (yoked-stressed group) were each paired to a rat in the avoidance-escape group. The remaining 24 rats were not subjected to footshock (unstressed group). Shock trials were intermittently presented in the home cage 24 h/day for 3 days, while alternation performance continued to be measured. Since only 12 test cages were available, each condition was repeated to achieve a final n of six rats per group. Pyridostigmine and physostigmine each decreased blood acetylcholinesterase levels by approximately 50%. Physostigmine also decreased brain cortical acetylcholinesterase levels by approximately 50%, while pyridostigmine had no effect on cortical acetylcholinesterase activity. Alternation performance was impaired on the first day of stress and then recovered. Neither pyridostigmine nor physostigmine affected performance in the absence of stress or increased the effects of stress alone. Corticosterone was significantly increased in the yoked stress group compared to unstressed controls. These data suggest that pyridostigmine does not exacerbate the effects of stress on performance or levels of stress hormones. Furthermore, these data do not suggest that stress enables pyridostigmine to cross the blood brain barrier.

Sex hormones affect acute and chronic stress responses in sexually dimorphic patterns: Consequences for depression models.

PubMed

Guo, Lei; Chen, Yi-Xi; Hu, Yu-Ting; Wu, Xue-Yan; He, Yang; Wu, Juan-Li; Huang, Man-Li; Mason, Matthew; Bao, Ai-Min

2018-05-21

Alterations in peripheral sex hormones may play an important role in sex differences in terms of stress responses and mood disorders. It is not yet known whether and how stress-related brain systems and brain sex steroid levels fluctuate in relation to changes in peripheral sex hormone levels, or whether the different sexes show different patterns. We aimed to investigate systematically, in male and female rats, the effect of decreased circulating sex hormone levels following gonadectomy on acute and chronic stress responses, manifested as changes in plasma and hypothalamic sex steroids and hypothalamic stress-related molecules. Experiment (Exp)-1: Rats (14 males, 14 females) were gonadectomized or sham-operated (intact); Exp-2: gonadectomized and intact rats (28 males, 28 females) were exposed to acute foot shock or no stressor; and Exp-3: gonadectomized and intact rats (32 males, 32 females) were exposed to chronic unpredictable mild stress (CUMS) or no stressor. For all rats, plasma and hypothalamic testosterone (T), estradiol (E2), and the expression of stress-related molecules were determined, including corticotropin-releasing hormone, vasopressin, oxytocin, aromatase, and the receptors for estrogens, androgens, glucocorticoids, and mineralocorticoids. Surprisingly, no significant correlation was observed in terms of plasma sex hormones, brain sex steroids, and hypothalamic stress-related molecule mRNAs (p > 0.113) in intact or gonadectomized, male or female, rats. Male and female rats, either intact or gonadectomized and exposed to acute or chronic stress, showed different patterns of stress-related molecule changes. Diminished peripheral sex hormone levels lead to different peripheral and central patterns of change in the stress response systems in male and female rats. This has implications for the choice of models for the study of the different types of mood disorders which also show sex differences. Copyright © 2018 Elsevier Ltd. All rights reserved.

Transient increase in alcohol self-administration following a period of chronic exposure to corticosterone

PubMed Central

Besheer, Joyce; Fisher, Kristen R.; Lindsay, Tessa G.; Cannady, Reginald

2013-01-01

Stressful life events and chronic stressors have been associated with escalations in alcohol drinking. Stress exposure leads to the secretion of glucocorticoids (cortisol in the human; corticosterone (CORT) in the rodent). To model a period of heightened elevations in CORT, the present work assessed the effects of chronic exposure to the stress hormone CORT on alcohol self-administration. Male Long Evans rats were trained to self-administer a sweetened alcohol solution (2% sucrose/15% alcohol) resulting in moderate levels of daily alcohol intake (0.5–0.7 g/kg). Following stable baseline operant self-administration, rats received CORT in the drinking water for 7 days. A transient increase in alcohol self-administration was observed on the first self-administration session following CORT exposure, and behavior returned to control levels by the second session. Control experiments determined that this increase in alcohol self-administration was specific to alcohol, unrelated to general motor activation, and functionally dissociated from decreased CORT levels at the time of testing. These results indicate that repeated exposure to heightened levels of stress hormone (e.g., as may be experienced during stressful episodes) has the potential to lead to exacerbated alcohol intake in low to moderate drinkers. Given that maladaptive drinking patterns, such as escalated alcohol drinking following stressful episodes, have the potential to put an individual at risk for future drinking disorders, utilization of this model will be important for examination of neuroadaptations that occur as a consequence of CORT exposure in order to better understand escalated drinking following stressful episodes in nondependent individuals. PMID:23643750

Thermo-mechanical design aspects of mercury bombardment ion thrusters.

NASA Technical Reports Server (NTRS)

Schnelker, D. E.; Kami, S.

1972-01-01

The mechanical design criteria are presented as background considerations for solving problems associated with the thermomechanical design of mercury ion bombardment thrusters. Various analytical procedures are used to aid in the development of thruster subassemblies and components in the fields of heat transfer, vibration, and stress analysis. Examples of these techniques which provide computer solutions to predict and control stress levels encountered during launch and operation of thruster systems are discussed. Computer models of specific examples are presented.

Behavior of stress generated in semiconductor chips with high-temperature joints: Influence of mechanical properties of joint materials

NASA Astrophysics Data System (ADS)

Ito, H.; Kuwahara, M.; Ohta, R.; Usui, M.

2018-04-01

High-temperature joint materials are indispensable to realizing next-generation power modules with high-output performance. However, crack initiation resulting from stress concentration in semiconductor chips joined with high-temperature joint materials remains a critical problem in high-temperature operation. Therefore, clarifying the quantitative influence of joint materials on the stress generated in chips is essential. This study investigates the stress behavior of chips joined by Ni-Sn solid-liquid interdiffusion (SLID), which results in a high-temperature joint material likely to generate cracks after joining or when under thermal cycling. The results are compared with those fabricated using three types of solders, Pb-10%Sn, Sn-0.7%Cu, and Sn-10%Sb (mass %), which are conventional joint materials with different melting points and mechanical properties. Using Ni-Sn SLID results in the generation of high compressive stress (500 MPa) without stress relaxation after the joining process in contrast to the case of solders in which the compressive stresses are low (<300 MPa) and decrease to still lower levels (<250 MPa). In addition, no stress relaxation occurs during thermal cycling when using Ni-Sn SLID, whereas stress relaxation is clearly observed during heating to 200 °C using solders. Different stress behaviors between Ni-Sn SLID and other joint materials are illustrated by their mechanical strength and resistance against plastic and creep deformation. These results suggest that stress relaxation in a chip is key in suppressing crack initiation in highly reliable modules during high-temperature operation.

Testosterone depletion increases the susceptibility of brain tissue to oxidative damage in a restraint stress mouse model.

PubMed

Son, Seung-Wan; Lee, Jin-Seok; Kim, Hyeong-Geug; Kim, Dong-Woon; Ahn, Yo-Chan; Son, Chang-Gue

2016-01-01

Among sex hormones, estrogen is particularly well known to act as neuroprotective agent. Unlike estrogen, testosterone has not been well investigated in regard to its effects on the brain, especially under psychological stress. To investigate the role of testosterone in oxidative brain injuries under psychological stress, we adapted an orchiectomy and restraint stress model. BALB/c mice were subjected to either an orchiectomy or sham operation. After allowing 15 days for recovery, mice were re-divided into four groups according to exposure of restraint stress: sham, sham plus stress, orchiectomy, and orchiectomy plus stress. Serum testosterone was undetectable in orchiectomized groups and restraint-induced stress significantly reduced testosterone levels in sham plus stress group. The serum levels of corticosterone and adrenaline were notably elevated by restraint stress, and these elevated hormones were markedly augmented by orchiectomy. Two oxidative stressors and biomarkers for lipid and protein peroxidation were significantly increased in the cerebral cortex and hippocampus by restraint stress, while the reverse pattern was observed in antioxidant enzymes. These results were supported by histopathological findings, with 4-hydroxynonenal staining for oxidative injury and Fluoro-Jade B staining showing the degenerating neurons. The aforementioned patterns of oxidative injury were accelerated by orchiectomy. These findings strongly suggest the conclusion that testosterone exerts a protective effect against oxidative brain damage, especially under stressed conditions. Unlike estrogen, the effects of testosterone on the brain have not been thoroughly investigated. In order to investigate the role of testosterone in oxidative brain injuries under psychological stress, we adapted an orchiectomy and restraint stress model. Orchiectomy markedly augmented the restraint stress-induced elevation of serum corticosterone and adrenaline levels as well as oxidative alterations in brain tissues, especially in the hippocampus. These findings are the first evidence that testosterone depletion makes the brain prone to oxidative injury. © 2015 International Society for Neurochemistry.

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

PubMed

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

2018-05-01

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

Placement of trans-sternal wires according to an ellipsoid pressure vessel model of sternal forces.

PubMed

Casha, Aaron R; Manché, Alex; Gauci, Marilyn; Camilleri-Podesta, Marie-Therese; Schembri-Wismayer, Pierre; Sant, Zdenka; Gatt, Ruben; Grima, Joseph N

2012-03-01

Dehiscence of median sternotomy wounds remains a clinical problem. Wall forces in thin-walled pressure vessels can be calculated by membrane stress theory. An ellipsoid pressure vessel model of sternal forces is presented together with its application for optimal wire placement in the sternum. Sternal forces were calculated by computational simulation using an ellipsoid chest wall model. Sternal forces were correlated with different sternal thicknesses and radio-density as measured by computerized tomography (CT) scans of the sternum. A comparison of alternative placement of trans-sternal wires located either at the levels of the costal cartilages or the intercostal spaces was made. The ellipsoid pressure vessel model shows that higher levels of stress are operative at increasing chest diameter (P < 0.001). CT scans show that the thickness of the sternal body is on average 3 mm and 30% thicker (P < 0.001) and 53% more radio-dense (P < 0.001) at the costal cartilage levels when compared with adjacent intercostal spaces. This results in a decrease of average sternal stress from 438 kPa at the intercostal space level to 338 kPa at the costal cartilage level (P = 0.003). Biomechanical modelling suggests that placement of trans-sternal wires at the thicker bone and more radio-dense level of the costal cartilages will result in reduced stress.

A prospective double-blinded randomized controlled trial comparing systemic stress response in Laparoascopic cholecystectomy between low-pressure and standard-pressure pneumoperitoneum.

PubMed

Shoar, Saeed; Naderan, Mohammad; Ebrahimpour, Hossein; Soroush, Ahmadreza; Nasiri, Shirzad; Movafegh, Ali; Khorgami, Zhamak

2016-04-01

Laparoscopic cholecystectomy (LC) has become the gold-standard treatment for gallstone diseases. However, despite huge reduction in operative injury, systemic stress response remains high. This randomized controlled trial (RCT) aimed to compare systemic stress response between 2 different techniques of CO2 pneumoperitoneum. Trough a prospective, double-blinded RCT, serum levels of cortisol, adrenaline, glucose, and C-reactive protein (CRP) were compared between the two groups consisted of 50 patients undergoing LC under low-pressure and standard-pressure CO2 pneimoperitoneum. A total of fifty patients undergoing LC were equally assigned to 2 groups of twenty five patients. Average age was 48 ± 13.8 years (range, 19-74 years). Operative time was similar between standard-pressure group (47.8 ± 16.8 min) and low-pressure group (53.6 ± 25.1). Moreover, intra-operative IV volume administration and urine output did not differ significantly between the 2 groups (p > 0.05). Although the average heart rate and mean arterial pressure were slightly higher in a standard-pressure group compared with a low-pressure group, serial measurements of these parameters were statistically similar between the 2 groups. Serial changes of serum levels of cortisol, glucose, adrenaline, and CRP were compared between surgery day, postoperative 6-h and 1st postoperative day, which did not differ significantly between the standard-pressure and the low-pressure groups (p > 0.05). Our study did not reveal any alteration in systemic stress response with reduction in intra-abdominal pressure of pneumoperitoneum in LC. RCT REGISTRATION: irct.ir ID: IRCT201110072982N5. Copyright © 2016 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

[Stress in surgeries].

PubMed

Daian, Márcia Rodrigues; Petroianu, Andy; Alberti, Luiz Ronaldo; Jeunon, Ester Eliane

2012-01-01

The purpose of this article was to provide the literature regarding the psychological stress in the peri-operative period of adult patients undergoing operations under general anesthesia. The articles were obtained by surveying the papers published and catalogued in the Medline Pubmed interface database, Lilacs and the Biblioteca Virtual de Saúde (BVS) since 1984, crossing the headings stress, surgery, general anesthesia, psychology. Over 800 articles related to stress and surgery were analyzed with regards to their relevance to the considered subject. Eighteen articles were related to psychological stress. Their results confirmed the presence of psychological and physical stress, during the peri-operative period as well as relation between stress and de clinical post-operative recovery. There is a gap regarding in the peri-operative period. More studies on psychological influence on stress may benefit patients and help professionals during the surgical treatment.

Application of fracture mechanics and half-cycle method to the prediction of fatigue life of B-52 aircraft pylon components

NASA Technical Reports Server (NTRS)

Ko, W. L.; Carter, A. L.; Totton, W. W.; Ficke, J. M.

1989-01-01

Stress intensity levels at various parts of the NASA B-52 carrier aircraft pylon were examined for the case when the pylon store was the space shuttle solid rocket booster drop test vehicle. Eight critical stress points were selected for the pylon fatigue analysis. Using fracture mechanics and the half-cycle theory (directly or indirectly) for the calculations of fatigue-crack growth ,the remaining fatigue life (number of flights left) was estimated for each critical part. It was found that the two rear hooks had relatively short fatigue life and that the front hook had the shortest fatigue life of all the parts analyzed. The rest of the pylon parts were found to be noncritical because of their extremely long fatigue life associated with the low operational stress levels.

Field-induced strain degradation of AlGaN/GaN high electron mobility transistors on a nanometer scale

NASA Astrophysics Data System (ADS)

Lin, Chung-Han; Doutt, D. R.; Mishra, U. K.; Merz, T. A.; Brillson, L. J.

2010-11-01

Nanoscale Kelvin probe force microscopy and depth-resolved cathodoluminescence spectroscopy reveal an electronic defect evolution inside operating AlGaN/GaN high electron mobility transistors with degradation under electric-field-induced stress. Off-state electrical stress results in micron-scale areas within the extrinsic drain expanding and decreasing in electric potential, midgap defects increasing by orders-of-magnitude at the AlGaN layer, and local Fermi levels lowering as gate-drain voltages increase above a characteristic stress threshold. The pronounced onset of defect formation, Fermi level movement, and transistor degradation at the threshold gate-drain voltage of J. A. del Alamo and J. Joh [Microelectron. Reliab. 49, 1200 (2009)] is consistent with crystal deformation and supports the inverse piezoelectric model of high electron mobility transistor degradation.

Inhibition of the pituitary-adrenal response to stress during deprivation-induced feeding

NASA Technical Reports Server (NTRS)

Heybach, J. P.; Vernikos-Danellis, J.

1979-01-01

Plasma corticosterone and plasma and pituitary ACTH concentrations were determined during feeding and after application of an acute stress at various times after food and water presentation to male rats maintained on a restricted feeding and watering schedule. Both plasma corticosterone and ACTH concentrations fell after the presentation of food and water, and this fall was accompanied by increased levels of ACTH in the pituitary gland. In addition, a rise in plasma levels of ACTH was inhibited in response to an acute stress applied at 0-5 min after presentation of food and water, but ACTH synthesis was not. This inhibition of ACTH and corticosterone secretion in response to stress was transient and dissipated as a relatively linear function of the interval between food presentation and application of the stress. The results suggest that this feeding-induced, corticosteroid-independent inhibition of pituitary-adrenal activity involves active inhibitory mechanisms operating initially on ACTH secretory processes of the pituitary and later on the synthesis of ACTH or on the secretion of hypothalamic corticotropin-releasing factor.

Static and dynamic stress analyses of the prototype high head Francis runner based on site measurement

NASA Astrophysics Data System (ADS)

Huang, X.; Oram, C.; Sick, M.

2014-03-01

More efforts are put on hydro-power to balance voltage and frequency within seconds for primary control in modern smart grids. This requires hydraulic turbines to run at off-design conditions. especially at low load or speed-no load. Besides. the tendency of increasing power output and decreasing weight of the turbine runners has also led to the high level vibration problem of the runners. especially high head Francis runners. Therefore. it is important to carry out the static and dynamic stress analyses of prototype high head Francis runners. This paper investigates the static and dynamic stresses on the prototype high head Francis runner based on site measurements and numerical simulations. The site measurements are performed with pressure transducers and strain gauges. Based on the measured results. computational fluid dynamics (CFD) simulations for the flow channel from stay vane to draft tube cone are performed. Static pressure distributions and dynamic pressure pulsations caused by rotor-stator interaction (RSI) are obtained under various operating conditions. With the CFD results. static and dynamic stresses on the runner at different operating points are calculated by means of the finite element method (FEM). The agreement between simulation and measurement is analysed with linear regression method. which indicates that the numerical result agrees well with that of measurement. Furthermore. the maximum static and dynamic stresses on the runner blade are obtained at various operating points. The relations of the maximum stresses and the power output are discussed in detail. The influences of the boundary conditions on the structural behaviour of the runner are also discussed.

Use of inpatient psychiatric services on a U.S. Army combat support post during Operations Desert Shield and Desert Storm: the stress of non-deployment.

PubMed

Koshes, R J; Rothberg, J M

1994-06-01

We studied the utilization of inpatient psychiatric services during Operations Desert Shield and Desert Storm (the Persian Gulf War of 1990-1991) on a U.S. Army combat support post. Inpatient psychiatric admissions and dispositions for the post's catchment area were tallied before, during, and after Operations Desert Shield and Desert Storm. Subjects included active duty soldiers (deployed soldiers were not studied while they were away from the post), their families, and retirees. Overall, there was no increase in psychiatric hospitalizations for active duty soldiers, their family members, or retirees. However, coincident with the return of soldiers from Operations Desert Shield and Desert Storm, the psychiatric proportion of all hospitalizations increased in the subpopulation of soldiers not deployed who had served less than 1 year. These soldiers in training may be more susceptible to increased stress levels associated with the return of soldiers from war because of their inadequate group bonding.

Use of structured personality survey techniques to indicate operator response to stressful situations

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

Waller, M.A.

Under given circumstances, a person will tend to operate in one of four dominant orientations: (1) to perform tasks; (2) to achieve consensus; (3) to achieve understanding, or (4) to maintain structure. Historically, personality survey techniques, such as the Myers-Briggs type indicator, have been used to determine these tendencies. While these techniques can accurately reflect a person's orientation under normal social situations, under different sets of conditions, the same person may exhibit other tendencies, displaying a similar or entirely different orientation. While most do not exhibit extreme tendencies or changes of orientation, the shift in personality from normal to stressfulmore » conditions can be rather dramatic, depending on the individual. Structured personality survey techniques have been used to indicate operator response to stressful situations. These techniques have been extended to indicate the balance between orientations that the control room team has through the various levels of cognizance.« less

40 CFR 264.573 - Design and operating requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., climatic conditions, the stress of daily operations, e.g., variable and moving loads such as vehicle... leakage to which they are exposed, climatic conditions, the stress of installation, and the stress of daily operation (including stresses from vehicular traffic on the drip pad); (ii) Placed upon a...

40 CFR 264.573 - Design and operating requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., climatic conditions, the stress of daily operations, e.g., variable and moving loads such as vehicle... leakage to which they are exposed, climatic conditions, the stress of installation, and the stress of daily operation (including stresses from vehicular traffic on the drip pad); (ii) Placed upon a...

40 CFR 264.573 - Design and operating requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., climatic conditions, the stress of daily operations, e.g., variable and moving loads such as vehicle... leakage to which they are exposed, climatic conditions, the stress of installation, and the stress of daily operation (including stresses from vehicular traffic on the drip pad); (ii) Placed upon a...

Individual differences in response to automation: the five factor model of personality.

PubMed

Szalma, James L; Taylor, Grant S

2011-06-01

This study examined the relationship of operator personality (Five Factor Model) and characteristics of the task and of adaptive automation (reliability and adaptiveness-whether the automation was well-matched to changes in task demand) to operator performance, workload, stress, and coping. This represents the first investigation of how the Five Factors relate to human response to automation. One-hundred-sixty-one college students experienced either 75% or 95% reliable automation provided with task loads of either two or four displays to be monitored. The task required threat detection in a simulated uninhabited ground vehicle (UGV) task. Task demand exerted the strongest influence on outcome variables. Automation characteristics did not directly impact workload or stress, but effects did emerge in the context of trait-task interactions that varied as a function of the dimension of workload and stress. The pattern of relationships of traits to dependent variables was generally moderated by at least one task factor. Neuroticism was related to poorer performance in some conditions, and all five traits were associated with at least one measure of workload and stress. Neuroticism generally predicted increased workload and stress and the other traits predicted decreased levels of these states. However, in the case of the relation of Extraversion and Agreeableness to Worry, Frustration, and avoidant coping, the direction of effects varied across task conditions. The results support incorporation of individual differences into automation design by identifying the relevant person characteristics and using the information to determine what functions to automate and the form and level of automation.

Impact of total hip arthroplasty on pain, walking ability, and cardiovascular fitness.

PubMed

Horstmann, Thomas; Vornholt-Koch, Sandra; Brauner, Torsten; Grau, Stefan; Mündermann, Annegret

2012-12-01

We tested the hypothesis that total hip arthroplasty (THA) patients have less pain and are able to walk longer post-operatively than pre-operatively, and that THA patients before and after have higher heart rates and compromised gas exchange determinants at rest and following exercise compared to healthy subjects with a post-operative improvement. Fifty-two patients completed questionnaires and an incremental walking stress test pre-operatively and 6-months after THA. Twenty-four age-matched control subjects completed the same stress test. Fifty-one patients had less pain 6-months after THA compared to pre-operative levels. Forty-three patients showed an improvement of at least one walking duration category. Patients had compromised cardiovascular fitness compared to the control group with a tendency to improve after THA. Hence, 6-months following THA, deficits exist other than reduced strength as reported in the literature. Prior to THA, the ability to walk longer is compromised by pain and not by poor cardiovascular fitness. Studies on specific rehabilitation programs of varying intensities may demonstrate opportunities to improve the cardiovascular fitness of this population. Copyright © 2012 Orthopaedic Research Society.

Testing of Face-milled Spiral Bevel Gears at High-speed and Load

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.

2001-01-01

Spiral bevel gears are an important drive system components of rotorcraft (helicopters) currently in use. In this application the spiral bevel gears are required to transmit very high torque at high rotational speed. Available experimental data on the operational characteristics for thermal and structural behavior is relatively small in comparison to that found for parallel axis gears. An ongoing test program has been in place at NASA Glenn Research Center over the last ten years to investigate their operational behavior at operating conditions found in aerospace applications. This paper will summarize the results of the tests conducted on face-milled spiral bevel gears. The data from the pinion member (temperature and stress) were taken at conditions from slow-roll to 14400 rpm and up to 537 kW (720 hp). The results have shown that operating temperature is affected by the location of the lubricating jet with respect to the point it is injected and the operating conditions that are imposed. Also the stress measured from slow-roll to very high rotational speed, at various torque levels, indicated little dynamic affect over the rotational speeds tested.

Maternal ADHD symptoms, personality, and parenting stress: Differences between mothers of children with ADHD and mothers of comparison children

PubMed Central

Algorta, Guillermo Perez; Kragh, Carolyn A.; Arnold, L. Eugene; Molina, Brooke S. G.; Hinshaw, Stephen P.; Swanson, James M.; Hetchman, Lily; Copley, LaRae M.; Lowe, Matthew; Jensen, Peter S.

2017-01-01

Mothers raising a child with ADHD can experience high parenting stress. Mothers’ personality traits and own ADHD symptoms could also affect parenting stress. 430 biological mothers from the Multimodal Treatment Study of Children with ADHD (MTA mothers) and 237 of a local normative comparison group (LNCG mothers) were evaluated at baseline. Interactions were tested between mothers’ group and maternal personality/ADHD symptoms related to parenting stress. Compared to LNCG, MTA mothers had higher parenting stress, self-reported ADHD, neuroticism, and lower conscientiousness and agreeableness. When personality and ADHD were evaluated together, ADHD symptoms interacted with mothers’ group: high maternal ADHD was positively associated with parenting stress for LNCG but not MTA mothers. Personality traits or ADHD characteristics do not appear operative for the high parenting stress of mothers of a child with ADHD. However, high maternal ADHD or low conscientiousness are associated with stress levels similar to raising a child with ADHD. PMID:25525155

Constitutive law for the densification of fused silica with applications in polishing and microgrinding

NASA Astrophysics Data System (ADS)

Lambropoulos, John C.; Fang, Tong; Xu, Su; Gracewski, Sheryl M.

1995-09-01

We discuss a constitutive model describing the permanent densification of fused silica under large applied pressures and shear stresses. The constitutive law is assumed to be rate- independent, and uses a yield function coupling hydrostatic pressure and shear stress, a flow rule describing the evolution of permanent strains after initial densification, and a hardening rule describing the dependence of the incremental densification on the levels of applied stresses. The constitutive law accounts for multiaxial states of stress, since during polishing and grinding operations complex stress states occur in a thin surface layer due to the action of abrasive particles. Due to frictional and other abrasive forces, large shear stresses are present near the surface during manufacturing. We apply the constitutive law in estimating the extent of the densified layer during the mechanical interaction of an abrasive grain and a flat surface.

[The effect of social support on women's perception of global stress and health status].

PubMed

Sprusińska, E; Makowska, Z

1992-01-01

Social support is considered to be an essential factor in the perception of global stress, as it reduces the impact of the stressors (and thereby protects against excessive stress), a well as reduces the detrimental effects of stress. The purpose of the study was to determine the level of social support received by women in two essential areas: family life and occupational work, and to estimate the relationships between the support level and stress perception by women and the condition of their health (estimated with the use of the Goldberg General Health Questionnaire). The APGAR questionnaire designed by G. Smilkstein was used to estimate the support. This was the first instance of the application of the method in a Polish study--with prior written consent of the author of the method. The study involved 98 women in four occupational groups (physicians, nurses, spinning machine operators, and employees of financial department of an industrial plant). The results of the study indicate that the situation of the women in respect of the received social support differs, to a statistically significant degree depending on the occupational group to which they belong. The evaluations of the support are also, significant correlated with the evaluations of global stress in the whole population test--higher results with respect to the support are correlated with the lower degree of stress. The support from the family shows higher degree of correlation with the level of the perceived stress than the support received at the place of employment.(ABSTRACT TRUNCATED AT 250 WORDS)

TVT compared with TVT-O and TOT: results from the Norwegian National Incontinence Registry.

PubMed

Dyrkorn, Ole A; Kulseng-Hanssen, Sigurd; Sandvik, Leiv

2010-11-01

The aim of this study is to compare the outcome and complication rates of the tension-free vaginal tape (TVT) operations with the transobturator vaginal tape (TVT-O and TOT) operations in the treatment of urinary stress incontinence. This is a multicenter, prospective cohort study. Preoperative and postoperative assessments included a validated Stress and Urge Incontinence Questionnaire, a 24-h pad test, and a standardized stress test. The study included 5,942 women--4,281 women had a TVT operation and 731 and 373 women had TVT-O and TOT operations, respectively. Median follow-up time was 8 months. Women in the TVT group had less leakage during stress test and fewer subjective stress incontinence symptoms, and were more satisfied with the operation compared with the women in TVT-O and TOT groups, but more complications were reported after TVT operation. The TVT operation is more efficient than TVT-O and TOT operations in treating stress incontinent women.

Machiavelli Now and Here: An Essay for the First World

ERIC Educational Resources Information Center

Adams, Robert M.

1975-01-01

Author reinterpreted Machiavelli's theme in the Prince by bringing his philosophy into practice in contemporary society and stressed the point that it is necessary to always operate on the ideal as well as the practical level when dealing with world affairs. (RK)

Cold and Heat Stress Diversely Alter Both Cauliflower Respiration and Distinct Mitochondrial Proteins Including OXPHOS Components and Matrix Enzymes

PubMed Central

Rurek, Michał; Czołpińska, Magdalena; Pawłowski, Tomasz Andrzej; Krzesiński, Włodzimierz; Spiżewski, Tomasz

2018-01-01

Complex proteomic and physiological approaches for studying cold and heat stress responses in plant mitochondria are still limited. Variations in the mitochondrial proteome of cauliflower (Brassica oleracea var. botrytis) curds after cold and heat and after stress recovery were assayed by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) in relation to mRNA abundance and respiratory parameters. Quantitative analysis of the mitochondrial proteome revealed numerous stress-affected protein spots. In cold, major downregulations in the level of photorespiratory enzymes, porine isoforms, oxidative phosphorylation (OXPHOS) and some low-abundant proteins were observed. In contrast, carbohydrate metabolism enzymes, heat-shock proteins, translation, protein import, and OXPHOS components were involved in heat response and recovery. Several transcriptomic and metabolic regulation mechanisms are also suggested. Cauliflower plants appeared less susceptible to heat; closed stomata in heat stress resulted in moderate photosynthetic, but only minor respiratory impairments, however, photosystem II performance was unaffected. Decreased photorespiration corresponded with proteomic alterations in cold. Our results show that cold and heat stress not only operate in diverse modes (exemplified by cold-specific accumulation of some heat shock proteins), but exert some associations at molecular and physiological levels. This implies a more complex model of action of investigated stresses on plant mitochondria. PMID:29547512

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

Radojcic, Riko; Nowak, Matt; Nakamoto, Mark

The status of the development of a Design-for-Stress simulation flow that captures the stress effects in packaged 3D-stacked Si products like integrated circuits (ICs) using advanced via-middle Through Si Via technology is outlined. The next set of challenges required to proliferate the methodology and to deploy it for making and dispositioning real Si product decisions are described here. These include the adoption and support of a Process Design Kit (PDK) that includes the relevant material properties, the development of stress simulation methodologies that operate at higher levels of abstraction in a design flow, and the development and adoption of suitablemore » models required to make real product reliability decisions.« less

EAP-based critical incident stress management: utilization of a practice-based assessment of incident severity level in responding to workplace trauma.

PubMed

DeFraia, Gary S

2013-01-01

Central to the field of trauma psychology is assessment of the impact of critical incidents on individuals, as measured by individual symptoms of stress. Accordingly, the trauma literature reflects a proliferation of clinical impact of event scales. Workplace incidents however, affect not only individual employees, but also work organizations, requiring a multi-level response. Critical incident stress management (CISM) is the most prevalent multi-level incident response strategy utilized by organizations, often through specialized CISM units operating within their employee assistance programs (EAPs). While EAP-based CISM units seeks to support both individuals and organizations, studies focused on individual stress dominate the literature, mirroring assessment scales that tend to emphasize clinical as opposed to organizational practice. This research contributes to less-prevalent studies exploring incident characteristics as disruptive to organizations, rather than clinical symptoms as disruptive to individuals. To measure incident disruption, an EAP-based CISM unit developed a critical incident severity scale. By analyzing this unit's extensive practice database, this exploratory study examines how critical incident severity level varies among various types of incidents. Employing the methodology of clinical data mining, this practice-based research generates evidence-informed practice recommendations in the areas of EAP-based CISM intake assessment, organizational consultation and incident response planning.

Endoplasmic reticulum stress increases brain MAPK signaling, inflammation and renin-angiotensin system activity and sympathetic nerve activity in heart failure

PubMed Central

Wei, Shun-Guang; Yu, Yang; Weiss, Robert M.

2016-01-01

We previously reported that endoplasmic reticulum (ER) stress is induced in the subfornical organ (SFO) and the hypothalamic paraventricular nucleus (PVN) of heart failure (HF) rats and is reduced by inhibition of mitogen-activated protein kinase (MAPK) signaling. The present study further examined the relationship between brain MAPK signaling, ER stress, and sympathetic excitation in HF. Sham-operated (Sham) and HF rats received a 4-wk intracerebroventricular (ICV) infusion of vehicle (Veh) or the ER stress inhibitor tauroursodeoxycholic acid (TUDCA, 10 μg/day). Lower mRNA levels of the ER stress biomarkers GRP78, ATF6, ATF4, and XBP-1s in the SFO and PVN of TUDCA-treated HF rats validated the efficacy of the TUDCA dose. The elevated levels of phosphorylated p44/42 and p38 MAPK in SFO and PVN of Veh-treated HF rats, compared with Sham rats, were significantly reduced in TUDCA-treated HF rats as shown by Western blot and immunofluorescent staining. Plasma norepinephrine levels were higher in Veh-treated HF rats, compared with Veh-treated Sham rats, and were significantly lower in the TUDCA-treated HF rats. TUDCA-treated HF rats also had lower mRNA levels for angiotensin converting enzyme, angiotensin II type 1 receptor, tumor necrosis factor-α, interleukin-1β, cyclooxygenase-2, and NF-κB p65, and a higher mRNA level of IκB-α, in the SFO and PVN than Veh-treated HF rats. These data suggest that ER stress contributes to the augmented sympathetic activity in HF by inducing MAPK signaling, thereby promoting inflammation and renin-angiotensin system activity in key cardiovascular regulatory regions of the brain. PMID:27496879

Does preoperative oral carbohydrate treatment reduce the postoperative surgical stress response in lumbar disc surgery?

PubMed

Dilmen, Ozlem Korkmaz; Yentur, Ercument; Tunali, Yusuf; Balci, Huriye; Bahar, Mois

2017-02-01

Surgical trauma produces metabolic and hormonal responses, which are characterized by insulin resistance. Due to extension of the preoperative fasting period, which increases the magnitude of postoperative insulin resistance, preoperative oral carbohydrates (POC) have been developed. This prospective, randomized, controlled study was performed on 43 ASA I-II patients undergoing elective microsurgical lumbar discectomy. The intervention group received oral carbohydrate solution 800mL the night before and 400mL 2h prior to operation. The other group fasted for 8h prior to operation. Blood samples were obtained the day before the operation, before induction of anesthesia, after skin incision, 1h, 2h, 6h and 24h following skin incision. Blood glucose, plasma insulin, cortisol and interleukin-6 (IL-6) levels were determined. The primary endpoint was to assess the effect of POC treatment on insulin resistance and surgical stress response following lumbar disc surgery. The secondary endpoint was to assess POC's effects on postoperative nausea and vomiting. The serum insulin levels were higher before induction of anesthesia in the study group and returned to fasted group levels by 2h after skin incision. The plasma IL-6 levels were higher in the intervention group at 6h after the skin incision. There were no differences between the two groups with respect to blood glucose, plasma cortisol levels and the incidence of nausea and vomiting. This study suggests that use of POC treatment does not attenuate development of insulin resistance in patients undergoing lumbar disc surgery. Copyright © 2016. Published by Elsevier B.V.

Gene expression of regulatory enzymes of glycolysis/gluconeogenesis in regenerating rat liver.

PubMed Central

Rosa, J L; Bartrons, R; Tauler, A

1992-01-01

Levels of mRNA for glucokinase, L-pyruvate kinase, fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase were analysed during liver regeneration. Levels of mRNA for glycolytic enzymes (glucokinase and L-pyruvate kinase) decreased rapidly after partial hepatectomy. Glucokinase mRNA increased at 16-24 h, returning to normal values after this time. L-pyruvate kinase mRNA recovered control levels at 168 h. In contrast, phosphoenolpyruvate carboxykinase mRNA increased rapidly after liver resection and remained high during the regenerative process. However, the levels of fructose-1,6-bisphosphatase mRNA were not modified significantly. These results correlate with the reported increased rate of gluconeogenesis and changes in enzyme levels after partial hepatectomy. The effect of stress on the mRNA levels was also studied. All enzymes showed variations in their mRNA levels after the surgical stress. In general, the differences were more pronounced in regenerating liver than in sham-operated animals, being practically normalized at 24 h. Images Fig. 2. Fig. 3. PMID:1329724

Aerodynamic performance of a fan stage utilizing Variable Inlet Guide Vanes (VIGVs) for thrust modulation. [subsonic V/STOL aircraft

NASA Technical Reports Server (NTRS)

Woollett, R. R.

1983-01-01

An experimental research program was conducted in the Lewis Research Center's 9x15-foot (2.74x4.57 m) low speed wind tunnel to evaluate the aerodynamic performance of an inlet and fan system with variable inlet guide vanes (VIGVs) for use on a subsonic V/STOL aircraft. At high VIGV blade angles (lower weight flow and thrust levels), the fan stage was stalled over a major portion of its radius. In spite of the stall, fan blade stresses only exceeded the limits at the most extreme flow conditions. It was found that inlet flow separation does not necessarily lead to poor inlet performance or adverse fan operating conditions. Generally speaking, separated inlet flow did not adversely affect the fan blade stress levels. There were some cases, however, at high VIGV angles and high inlet angles-of-attack where excessive blade stress levels were encountered. An evaluation term made up of the product of the distortion parameter, K alpha, the weight flow and the fan pressure ratio minus one, was found to correlate quite well with the observed blade stress results.

Aerodynamic performance of a fan stage utilizing variable inlet guide vanes (VIGV's) for thrust modulation. [subsonic V/STOL aircraft

NASA Technical Reports Server (NTRS)

Woollett, R. R.

1983-01-01

An experimental research program was conducted in the Lewis Research Center's 9 x 15-foot (2.74 x 4.57 m) low speed wind tunnel to evaluate the aerodynamic performance of an inlet and fan system with variable inlet guide vanes (VIGVs) for use on a subsonic V/STOL aircraft. At high VIGV blade angles (lower weight flow and thrust levels), the fan stage was stalled over a major portion of its radius. In spite of the stall, fan blade stresses only exceeded the limits at the most extreme flow conditions. It was found that inlet flow separation does not necessarily lead to poor inlet performance or adverse fan operating conditions. Generally speaking, separated inlet flow did not adversely affect the fan blade stress levels. There were some cases, however, at high VIGV angles and high inlet angles-of-attack where excessive blade stress levels were encountered. An evaluation term made up of the product of the distortion parameter, K alpha, the weight flow and the fan pressure ratio minus one, was found to correlate quite well with the observed blade stress results. Previously announced in STAR as N83-27957

Comparison of perioperative stress in patients undergoing thyroid surgery with and without neuromonitoring-a pilot study.

PubMed

Babińska, Dominika; Barczyński, Marcin; Osęka, Tomasz; Śledziński, Maciej; Łachiński, Andrzej J

2017-06-01

A comprehensive psychological comparison of preoperative stress in patients scheduled for thyroidectomy with versus without intraoperative neurophysiologic monitoring (IONM) has never been reported. The aim of this study was to assess whether a planned utilization of IONM had any effect on the reduction of stress and anxiety level before and after thyroid surgery. The outcomes of 32 patients scheduled for thyroidectomy with IONM were compared to the outcomes of a carefully matched control group of 39 patients operated on without IONM. All the patients were tested before the surgery and at 1-7 days postoperatively employing psychological self-report instruments: the Depression Anxiety Stress Scales (DASS), State-Trait Anxiety Inventory (STAI), 12-item General Health Questionnaire (GHQ), Functional Assessment of Cancer Therapy-Head and Neck Scale (FACT H&N), and the visual analog scale (VAS). The examined groups were homogenous and carefully matched in terms of mental health (GHQ), the quality of life (FACT H&N), and the intensity of depression level (DASS). The IONM group showed a significantly lower level of "the state anxiety"(STAI) 1 day before the operation (p < 0.05), greater trust in the doctor (VAS) (p < 0.05), and greater confidence in the treatment method (VAS) as compared to the patients in the control group (p < 0.05), while no significant differences were found when the remaining items were compared. The planned use of IONM during thyroidectomy may reduce patient anxiety before surgery. However, further research in this area is necessary to confirm this preliminary finding in a larger population of patients.

Stress and salivary cortisol in emergency medical dispatchers: A randomized shifts control trial

PubMed Central

Bedini, Sarah; Braun, François; Weibel, Laurence; Aussedat, Michel; Pereira, Bruno; Dutheil, Frédéric

2017-01-01

Stress at work is a public health concern. Phone operators in emergency medical dispatch centers are particularly at risk. We aimed to demonstrate that the most stressful time for emergency medical dispatchers is the shift when they receive emergency incoming calls, with cortisol as a biomarker of stress. For each emergency medical dispatcher, we measured outcomes over a control day and during three types of shift: Incoming emergency call, Dispatch and Re-assessment. The pattern of shifts was randomized. Saliva was sampled every 15 minutes for 2 hours, i.e. 6 consecutive times, starting 15 minutes after the first life-and-death incoming emergency call between 2 and 5 pm during three types of shift. We measured saliva cortisol every 2 hours over a control day, from 7am to 9pm. Perceived stress was assessed by a visual analog scale. We recruited 22 phone operators aged 36.4+/-10.8 years old (14 women and 8 men). Cortisol values were higher during the Incoming emergency call shift than during the Dispatch (p = .04) and Re-assessment (p = .04) shifts. The increase in cortisol levels was greater in men than in women (p = .009). There were no differences between control values and those of the three shifts. The kinetics of cortisol increased with greater perceived stress overall (p < .001) and for each type of shift (Incoming emergency call, p = .02; Dispatch p = .03; Re-assessment: p < .001). The kinetics of cortisol in response to incoming emergency calls was greater when the call was an absolute emergency (p = .03), and also tended to further increase when a subsequent absolute incoming emergency call was received (p = 0.07). In conclusion, the incoming emergency call shift carries particular risk for dispatchers, who have greater perceived stress and a greater increase in cortisol levels. PMID:28505199

Stress and salivary cortisol in emergency medical dispatchers: A randomized shifts control trial.

PubMed

Bedini, Sarah; Braun, François; Weibel, Laurence; Aussedat, Michel; Pereira, Bruno; Dutheil, Frédéric

2017-01-01

Stress at work is a public health concern. Phone operators in emergency medical dispatch centers are particularly at risk. We aimed to demonstrate that the most stressful time for emergency medical dispatchers is the shift when they receive emergency incoming calls, with cortisol as a biomarker of stress. For each emergency medical dispatcher, we measured outcomes over a control day and during three types of shift: Incoming emergency call, Dispatch and Re-assessment. The pattern of shifts was randomized. Saliva was sampled every 15 minutes for 2 hours, i.e. 6 consecutive times, starting 15 minutes after the first life-and-death incoming emergency call between 2 and 5 pm during three types of shift. We measured saliva cortisol every 2 hours over a control day, from 7am to 9pm. Perceived stress was assessed by a visual analog scale. We recruited 22 phone operators aged 36.4+/-10.8 years old (14 women and 8 men). Cortisol values were higher during the Incoming emergency call shift than during the Dispatch (p = .04) and Re-assessment (p = .04) shifts. The increase in cortisol levels was greater in men than in women (p = .009). There were no differences between control values and those of the three shifts. The kinetics of cortisol increased with greater perceived stress overall (p < .001) and for each type of shift (Incoming emergency call, p = .02; Dispatch p = .03; Re-assessment: p < .001). The kinetics of cortisol in response to incoming emergency calls was greater when the call was an absolute emergency (p = .03), and also tended to further increase when a subsequent absolute incoming emergency call was received (p = 0.07). In conclusion, the incoming emergency call shift carries particular risk for dispatchers, who have greater perceived stress and a greater increase in cortisol levels.

49 CFR 192.323 - Casing.

Code of Federal Regulations, 2011 CFR

2011-10-01

... loads. (b) If there is a possibility of water entering the casing, the ends must be sealed. (c) If the... operating pressure of the pipe, the casing must be designed to hold this pressure at a stress level of not... the weather to prevent water from entering the casing. ...

49 CFR 192.323 - Casing.

Code of Federal Regulations, 2010 CFR

2010-10-01

... loads. (b) If there is a possibility of water entering the casing, the ends must be sealed. (c) If the... operating pressure of the pipe, the casing must be designed to hold this pressure at a stress level of not... the weather to prevent water from entering the casing. ...

School Community Relations and Resources in Effective Schools.

ERIC Educational Resources Information Center

Michel, George J.

1985-01-01

Discusses resources available to schools operating as open and closed systems. Examines school/community relations and school effectiveness, schools as resource machines, and resources offered by teachers and parents. Stresses that broad concepts of community, good communication, and citizen involvement can utilize resources at high levels of…

49 CFR 192.505 - Strength test requirements for steel pipeline to operate at a hoop stress of 30 percent or more...

Code of Federal Regulations, 2010 CFR

2010-10-01

... operate at a hoop stress of 30 percent or more of SMYS. 192.505 Section 192.505 Transportation Other... to operate at a hoop stress of 30 percent or more of SMYS. (a) Except for service lines, each segment of a steel pipeline that is to operate at a hoop stress of 30 percent or more of SMYS must be...

49 CFR 192.505 - Strength test requirements for steel pipeline to operate at a hoop stress of 30 percent or more...

Code of Federal Regulations, 2012 CFR

2012-10-01

... operate at a hoop stress of 30 percent or more of SMYS. 192.505 Section 192.505 Transportation Other... to operate at a hoop stress of 30 percent or more of SMYS. (a) Except for service lines, each segment of a steel pipeline that is to operate at a hoop stress of 30 percent or more of SMYS must be...

49 CFR 192.505 - Strength test requirements for steel pipeline to operate at a hoop stress of 30 percent or more...

Code of Federal Regulations, 2014 CFR

2014-10-01

... operate at a hoop stress of 30 percent or more of SMYS. 192.505 Section 192.505 Transportation Other... to operate at a hoop stress of 30 percent or more of SMYS. (a) Except for service lines, each segment of a steel pipeline that is to operate at a hoop stress of 30 percent or more of SMYS must be...

49 CFR 192.505 - Strength test requirements for steel pipeline to operate at a hoop stress of 30 percent or more...

Code of Federal Regulations, 2011 CFR

2011-10-01

... operate at a hoop stress of 30 percent or more of SMYS. 192.505 Section 192.505 Transportation Other... to operate at a hoop stress of 30 percent or more of SMYS. (a) Except for service lines, each segment of a steel pipeline that is to operate at a hoop stress of 30 percent or more of SMYS must be...

Thyroid hormones effects on oxidative stress and cardiac remodeling in the right ventricle of infarcted rats.

PubMed

Corssac, Giana B; de Castro, Alexandre L; Tavares, Angela V; Campos, Cristina; Fernandes, Rafael O; Ortiz, Vanessa D; Siqueira, Rafaela; Fernandes, Tânia Regina G; Belló-Klein, Adriane; Araujo, Alex Sander R

2016-02-01

Right ventricle (RV) dysfunction post-myocardial infarction (MI) was associated with a worsened prognosis. In this scenario, reactive oxygen species (ROS) are related with the progression from MI to heart failure. Previous work showed that thyroid hormones (TH) are cardioprotective after MI. This study aims to investigate the effect of T3 and T4 administration on oxidative stress and angiogenesis parameters in the RV after MI. Wistar rats were allocated into four groups: Sham-operated (SHAM), infarcted (AMI), sham-operated + TH (SHAMT), and infarcted+TH (AMIT). The treated groups received T3 (2 μg/100g/day) and T4 (8 μg/100g/day) by gavage for 26 days. After this, echocardiographic analysis was performed and the RV was collected to western blot and biochemical analysis. Infarcted treated rats showed RV hypertrophy compared with AMI and SHAMT. Hydrogen peroxide levels were decrease and SOD activity and expression were increased in the infarcted treated rats. Besides that, the hormonal administration increased eNOS expression and prevented the reduction of VEGF levels in AMIT rats. In conclusion, TH seems to improve oxidative stress parameters, to promote physiological hypertrophy and to increase the expression of proteins involved with angiogenesis in the right heart. Copyright © 2016 Elsevier Inc. All rights reserved.

Response of single bacterial cells to stress gives rise to complex history dependence at the population level

PubMed Central

Mathis, Roland; Ackermann, Martin

2016-01-01

Most bacteria live in ever-changing environments where periods of stress are common. One fundamental question is whether individual bacterial cells have an increased tolerance to stress if they recently have been exposed to lower levels of the same stressor. To address this question, we worked with the bacterium Caulobacter crescentus and asked whether exposure to a moderate concentration of sodium chloride would affect survival during later exposure to a higher concentration. We found that the effects measured at the population level depended in a surprising and complex way on the time interval between the two exposure events: The effect of the first exposure on survival of the second exposure was positive for some time intervals but negative for others. We hypothesized that the complex pattern of history dependence at the population level was a consequence of the responses of individual cells to sodium chloride that we observed: (i) exposure to moderate concentrations of sodium chloride caused delays in cell division and led to cell-cycle synchronization, and (ii) whether a bacterium would survive subsequent exposure to higher concentrations was dependent on the cell-cycle state. Using computational modeling, we demonstrated that indeed the combination of these two effects could explain the complex patterns of history dependence observed at the population level. Our insight into how the behavior of single cells scales up to processes at the population level provides a perspective on how organisms operate in dynamic environments with fluctuating stress exposure. PMID:26960998

Multidimensional Profiling of Task Stress States for Human Factors: A Brief Review.

PubMed

Matthews, Gerald

2016-09-01

This article advocates multidimensional assessment of task stress in human factors and reviews the use of the Dundee Stress State Questionnaire (DSSQ) for evaluation of systems and operators. Contemporary stress research has progressed from an exclusive focus on environmental stressors to transactional perspectives on the stress process. Performance impacts of stress reflect the operator's dynamic attempts to understand and cope with task demands. Multidimensional stress assessments are necessary to gauge the different forms of system-operator interaction. This review discusses the theoretical and practical use of the DSSQ in evaluating multidimensional patterns of stress response. It presents psychometric evidence for the multidimensional perspective and illustrative profiles of subjective state response to task stressors and environments. Evidence is also presented on stress state correlations with related variables, including personality, stress process measures, psychophysiological response, and objective task performance. Evidence supports the validity of the DSSQ as a task stress measure. Studies of various simulated environments show that different tasks elicit different profiles of stress state response. Operator characteristics such as resilience predict individual differences in state response to stressors. Structural equation modeling may be used to understand performance impacts of stress states. Multidimensional assessment affords insight into the stress process in a variety of human factors contexts. Integrating subjective and psychophysiological assessment is a priority for future research. Stress state measurement contributes to evaluating system design, countermeasures to stress and fatigue, and performance vulnerabilities. It may also support personnel selection and diagnostic monitoring of operators. © 2016, Human Factors and Ergonomics Society.

Performance Evaluation of a Salivary Amylase Biosensor for Stress Assessment in Military Field Research.

PubMed

Peng, Henry T; Savage, Erin; Vartanian, Oshin; Smith, Shane; Rhind, Shawn G; Tenn, Catherine; Bjamason, Stephen

2016-05-01

A convenient biosensor for real-time measurement of biomarkers for in-field psychophysiological stress research and military operations is desirable. We evaluated a hand-held device for measuring salivary amylase as a stress marker in medical technicians undergoing combat casualty care training using two different modalities in operating room and field settings. Salivary amylase activity was measured by two biosensor methods: directly sampling saliva with a test strip placed under the tongue or pipetting a fixed volume of precollected saliva onto the test strip, followed by analyzing the sample on the strip using a biosensor. The two methods were compared for their accuracy and sensitivity to detect the stress response using an enzyme assay method as a standard. The measurements from the under-the-tongue method were not as consistent with those from the standard assay method as the values obtained from the pipetting method. The under-the-tongue method did not detect any significant increase in the amylase activity due to stress in the operating room (P > 0.1), in contrast to the significant increases observed using the pipetting method and assay method with a significance level less than 0.05 and 0.1, respectively. Furthermore, the under-the-tongue method showed no increased amylase activity in the field testing, while both the pipetting method and assay method showed increased amylase activity in the same group (P < 0.1). The accuracy and consistency of the biosensors need to be improved when used to directly measure salivary amylase activity under the tongue for stress assessment in military medical training. © 2015 Her Majesty the Queen in Right of Canada. Journal of Clinical Laboratory Analysis published by Wiley Periodicals, Inc. Reproduced with the permission DRDC Editorial Board.

Spring 2014 Internship Diffuser Data Analysis

NASA Technical Reports Server (NTRS)

Laigaie, Robert T.; Ryan, Harry M.

2014-01-01

J-2X engine testing on the A-2 test stand at the NASA John C. Stennis Space Center (SSC) has recently concluded. As part of that test campaign, the engine was operated at lower power levels in support of expanding the use of J-2X to other missions. However, the A-2 diffuser was not designed for engine testing at the proposed low power levels. To evaluate the risk of damage to the diffuser, computer simulations were created of the rocket engine exhaust plume inside the 50ft long, water-cooled, altitude-simulating diffuser. The simulations predicted that low power level testing would cause the plume to oscillate in the lower sections of the diffuser. This can possibly cause excessive vibrations, stress, and heat transfer from the plume to the diffuser walls. To understand and assess the performance of the diffuser during low power level engine testing, nine accelerometers and four strain gages were installed around the outer surface of the diffuser. The added instrumentation also allowed for the verification of the rocket exhaust plume computational model. Prior to engine hot-fire testing, a diffuser water-flow test was conducted to verify the proper operation of the newly installed instrumentation. Subsequently, two J-2X engine hot-fire tests were completed. Hot-Fire Test 1 was 11.5 seconds in duration, and accelerometer and strain data verified that the rocket engine plume oscillated in the lower sections of the diffuser. The accelerometers showed very different results dependent upon location. The diffuser consists of four sections, with Section 1 being closest to the engine nozzle and Section 4 being farthest from the engine nozzle. Section 1 accelerometers showed increased amplitudes at startup and shutdown, but low amplitudes while the diffuser was started. Section 3 accelerometers showed the opposite results with near zero G amplitudes prior to and after diffuser start and peak amplitudes to +/- 100G while the diffuser was started. Hot-Fire Test 1 strain gages showed different data dependent on section. Section 1 strains were small, and were in the range of 50 to 150 microstrain, which would result in stresses from 1.45 to 4.35 ksi. The yield stress of the material, A-285 Grade C Steel, is 29.7 ksi. Section 4 strain gages showed much higher values with strains peaking at 1600 microstrain. This strain corresponds to a stress of 46.41 ksi, which is in excess of the yield stress, but below the ultimate stress of 55 to 75 ksi. The decreased accelerations and strain in Section 1, and the increased accelerations and strain in Sections 3 and 4 verified the computer simulation prediction of increased plume oscillations in the lower sections of the diffuser. Hot-Fire Test 2 ran for a duration of 125 seconds. The engine operated at a slightly higher power level than Hot-Fire Test 1 for the initial 35 seconds of the test. After 35 seconds the power level was lowered to Hot-Fire Test 1 levels. The acceleration and strain data for Hot-Fire Test 2 was similar during the initial part of the test. However, just prior to the engine being lowered to the Hot-Fire Test 1 power level, the strain gage data in Section 4 showed a large decrease to strains near zero microstrain from their peak at 1500 microstrain. Future work includes further strain and acceleration data analysis and evaluation.

Modulatory effects of caffeine on oxidative stress and anxiety-like behavior in ovariectomized rats.

PubMed

Caravan, Ionut; Sevastre Berghian, Alexandra; Moldovan, Remus; Decea, Nicoleta; Orasan, Remus; Filip, Gabriela Adriana

2016-09-01

Menopause is accompanied by enhanced oxidative stress and behavioral changes, effects attenuated by antioxidants. The aim of this study was to evaluate the effects of caffeine on behavior and oxidative stress in an experimental model of menopause. Female rats were divided into the following groups: sham-operated (CON), sham-operated and caffeine-treated (CAF), ovariectomized (OVX), ovariectomized and caffeine-treated (OVX+CAF). Caffeine (6 mg/kg) and vehicle were administered for 21 days (subchronic) and 42 days (chronic), using 2 experimental subsets. Behavioral tests and oxidative stress parameters in the blood, whole brain, and hippocampus were assessed. The subchronic administration of caffeine decreased the lipid peroxidation and improved the antioxidant defense in the blood and brain. The GSH/GGSG ratio in the brain was improved by chronic administration, with reduced activities of antioxidant enzymes and enhanced nitric oxide and malondialdehyde levels. In particular, the lipid peroxidation in the hippocampus decreased in both experiments. The rats became hyperactive after 21 days of treatment, but no effect was observed after chronic administration. In both experimental subsets, caffeine had anxiolytic effects as tested in elevated plus maze. The administration of low doses of caffeine, for a short period of time, may be a new therapeutic approach to modulating the oxidative stress and anxiety in menopause.

A series-resonant silicon-controlled-rectifier power processor for ion thrusters

NASA Technical Reports Server (NTRS)

Shumaker, H. A.; Biess, J. J.; Goldin, D. S.

1973-01-01

A program to develop a power processing system for ion thrusters is presented. Basic operation of the silicon controlled rectifier series inverter circuitry is examined. The approach for synthesizing such circuits into a system which limits the electrical stress levels on the power source, semiconductor switching elements, and the ion thruster load is described. Experimental results are presented for a 2.5-kW breadboard system designed to operate a 20-cm ion thruster.

Financial stress, parent functioning and adolescent problem behavior: an actor-partner interdependence approach to family stress processes in low-, middle-, and high-income families.

PubMed

Ponnet, Koen

2014-10-01

The family stress model proposes that financial stress experienced by parents is associated with problem behavior in adolescents. The present study applied an actor-partner interdependence approach to the family stress model and focused on low-, middle-, and high-income families to broaden our understanding of the pathways by which the financial stress of mothers and fathers are related to adolescent outcomes. The study uses dyadic data (N = 798 heterosexual couples) from the Relationship between Mothers, Fathers and Children study in which two-parent families with an adolescent between 11 and 17 years of age participated. Path-analytic results indicated that in each of the families the association between parents' financial stress and problem behavior in adolescents is mediated through parents' depressive symptoms, interparental conflict, and positive parenting. Family stress processes also appear to operate in different ways for low-, middle-, and high-income families. In addition to a higher absolute level of financial stress in low-income families, financial stress experienced by mothers and fathers in these families had significant direct and indirect effects on problem behavior in adolescents, while in middle- and high-income families only significant indirect effects were found. The financial stress of a low-income mother also had a more detrimental impact on her level of depressive feelings than it had on mothers in middle-income families. Furthermore, the study revealed gender differences in the pathways of mothers and fathers. Implications for research, clinical practice, and policy are also discussed.

Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells

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

Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao

The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4–5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba{sup 2+}-sensitive inward rectifier K{sup +} current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level butmore » not at mRNA level after the hypoxic culture. Ca{sup 2+} imaging study revealed that the hypoxic stress enhanced store-operated Ca{sup 2+} (SOC) entry, which was significantly reduced in the presence of 100 μM Ba{sup 2+}. On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba{sup 2+}. We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca{sup 2+} entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. -- Highlights: •Hypoxic culture of brain endothelial cells (BEC) caused membrane hyperpolarization. •This hyperpolarization was due to the increased expression of Kir2.1 channels. •Hypoxia enhanced store-operated Ca{sup 2+} (SOC) entry via Kir2.1 up-regulation. •Expression levels of putative SOC channels were not affected by hypoxia. •Kir2.1 up-regulation is responsible for hypoxia-enhanced BEC proliferation.« less

Explicit control of adaptive automation under different levels of environmental stress.

PubMed

Sauer, Jürgen; Kao, Chung-Shan; Wastell, David; Nickel, Peter

2011-08-01

This article examines the effectiveness of three different forms of explicit control of adaptive automation under low- and high-stress conditions, operationalised by different levels of noise. In total, 60 participants were assigned to one of three types of automation design (free, prompted and forced choice). They were trained for 4 h on a highly automated simulation of a process control environment, called AutoCAMS. This was followed by a 4-h testing session under noise exposure and quiet conditions. Measures of performance, psychophysiology and subjective reactions were taken. The results showed that all three modes of explicit control of adaptive automation modes were able to attenuate the negative effects of noise. This was partly due to the fact that operators opted for higher levels of automation under noise. It also emerged that forced choice showed marginal advantages over the two other automation modes. Statement of Relevance: This work is relevant to the design of adaptive automation since it emphasises the need to consider the impact of work-related stressors during task completion. During the presence of stressors, different forms of operator support through automation may be required than under more favourable working conditions.

Rates and patterns of plankton response to stress exposure under natural conditions

NASA Astrophysics Data System (ADS)

Kucera, M.; Weinkauf, M.

2016-02-01

The effects of long-term exposure to natural levels of stress are often difficult to assess directly, because the resulting physiological changes and adaptations occur over times scales that cannot be covered by observations and where the outcome of the exposure cannot be predicted. Biometric studies on fossils provide a unique opportunity bridge this time scale and provide information on the reaction of populations to different levels of stress, including stress leading to extinction. In this respect, planktonic foraminifera represent a suitable model organism. This is because their shells, which are well preserved in marine sediments, record their entire ontogeny and allow assessment of developmental stability. Here we studied fossil populations of planktonic foraminifera transitioning into a high-stress environment during the onset of the deposition of Sapropel S5 in the Eastern Mediterranean, which culminated in local extinctions of several species. We show that calcification intensity (i.e. the amount of calcite secreted for a given body size) showed a strong and rapid reaction to surface water perturbation, with the same direction of change all species but no change prior to extinction, indicating that this parameters is primarily under environmental control. In contrast, shell morphology was not strictly tied to environmental change, but we observed large and rapid deviations in developmental stability immediately preceding local extinctions. It seems that developmental stability throughout ontogeny can be disrupted by enhanced stress levels leading to increased variation. This mechanism seems to operate on very short (decadal) time scales. It can potentially play a role in microevolution, and may be useful as an environmental stress proxy in plankton communities.

Miniature, ruggedized data collector

NASA Astrophysics Data System (ADS)

Jackson, Scott; Calcutt, Wade; Knobler, Ron; Jones, Barry; Klug, Robert

2009-05-01

McQ has developed a miniaturized, programmable, ruggedized data collector intended for use in weapon testing or data collection exercises that impose severe stresses on devices under test. The recorder is designed to survive these stresses which include acceleration and shock levels up to 100,000 G. The collector acquires and stores up to four channels of signal data to nonvolatile memory for later retrieval by a user. It is small (< 7 in3), light weight (< 1 lb), and can operate from various battery chemistries. A built-in menuing system, accessible via a USB interface, allows the user to configure parameters of the recorder operation, such as channel gain, filtering, and signal offsets, and also to retrieve recorded data for analysis. An overview of the collector, its features, performance, and potential uses, is presented.

Ultraviolet B irradiation of the mouse eye induces pigmentation of the skin more strongly than does stress loading, by increasing the levels of prohormone convertase 2 and α-melanocyte-stimulating hormone.

PubMed

Hiramoto, K; Yamate, Y; Kobayashi, H; Ishii, M; Sato, E F; Inoue, M

2013-01-01

In previous studies, we made the unexpected finding that in mice, ultraviolet (UV)B irradiation of the eye increased the concentration of α-melanocyte-stimulating hormone (α-MSH) in plasma, and systemically stimulated epidermal melanocytes. To compare the extent of the pigmentation induced by social and restraint stress (which activate the hippocampus-pituitary system) with that induced by UVB irradiation. DBA/2 and sham-operated or hypophysectomized DBA/2 mice were subjected to local UVB exposure using a sunlamp directed at the eye, and two types of stress (social and restraint) were imposed. UVB irradiation of the eye or exposure to stress loading both increased the number of Dopa-positive melanocytes in the epidermis, and hypophysectomy strongly inhibited the UVB-induced and stress-induced stimulation of melanocytes. Irradiation of the eye caused a much greater increase in dopamine than did the stress load. Both UVB eye irradiation and stress increased the blood levels of α-MSH and adrenocorticotropic hormone (ACTH). In addition, the increase in plasma α-MSH was greater in animals subjected to UVB eye irradiation than in those subjected to stress loading, whereas the reverse occurred for plasma ACTH. UVB irradiation to the eye and stress loading increased the expression of prohormone convertase (PC)1/3 and PC2 in the pituitary gland. The increase in expression of pituitary PC2 was greater in animals subjected to UVB eye irradiation than to stress, whereas no difference was seen between the two groups for the increase in PC1/3. UVB eye irradiation exerts a stronger effect on pigmentation than stress loading, and is related to increased levels of α-MSH and PC2. © The Author(s). CED © 2012 British Association of Dermatologists.

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

PubMed

Omholt, M L; Tveito, T H; Ihlebæk, C

2017-03-01

The European civilian aviation industry has undergone major changes in the last decade. Despite this, there is little knowledge about work-related stress and subjective health complaints (SHCs) affecting Norwegian aircrew. To investigate the relationships between work-related stress, self-efficacy and SHCs in commercial aircrew in Norway and to explore differences between cockpit and cabin crew. Aircrew members from the three major airlines operating from Norway completed an electronically distributed questionnaire. Linear regression analyses were used to investigate the association between work-related stress, self-efficacy and SHCs. There was a 21% response rate. Among the 843 study subjects, tiredness, sleep problems, bloating, low back pain, headaches and neck pain were the most prevalent SHCs. Cabin crew reported significantly higher numbers, prevalences and mean values for all SHCs compared with cockpit crew (P < 0.05). In total, 20% reported high stress levels. High levels of work-related stress were significantly associated with all SHC factors in both groups. Self-efficacy partly moderated the relationship between stress and psychological complaints in both cockpit and cabin crew, and for musculoskeletal complaints in cockpit crew. The model explained 23 and 32% of the variance in psychological complaints for cockpit and cabin crew, respectively. Commercial aircrew in Norway reported high numbers of SHCs, and high levels of work-related stress were associated with high numbers of SHC. More knowledge is needed on the physical, organizational and psychosocial stressors affecting cockpit and cabin crew in order to create a healthier work environment for these groups. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Effects of Energy Dissipation Rate on Islets of Langerhans: Implications for Isolation and Transplantation

PubMed Central

Shenkman, Rustin M.; Godoy-Silva, Ruben; Papas, Klearchos K.; Chalmers, Jeffrey J.

2010-01-01

Acute physical stresses can occur in the procurement and isolation process and potentially can contribute to islet death or malfunction upon transplantation. A contractional flow device, previously used to subject suspended cells to well-defined hydrodynamic forces, has been modified and used to assess the vulnerability of porcine islets of Langerhans to hydrodynamic forces. The flow profiles and velocity gradients in this modified device were modeled using commercial CFD software and characterized, as in previous studies, with the scalar parameter, energy dissipation rate (EDR). Porcine islets were stressed in a single pass at various stress levels (i.e., values of EDR). Membrane integrity, oxygen uptake rate, caspase 3/7 activity, and insulin release were not affected by the levels of fluid stress tested up to an EDR of 2 × 103 W/m3. Visual observation of the stressed islets suggested that cells at the islet exterior were peeled away at EDR greater than 10,000 W/m3, however, this observation could not be confirmed using image analysis software, which determined the ratio of surface perimeter to total area. The result of this study suggests an upper limit in fluid stress to which islets can be subjected. Such upper limits assist in the design and operation of future islet processing equipment and processes. PMID:19191351

The regulation of thermal stress induced apoptosis in corals reveals high similarities in gene expression and function to higher animals

NASA Astrophysics Data System (ADS)

Kvitt, Hagit; Rosenfeld, Hanna; Tchernov, Dan

2016-07-01

Recent studies suggest that controlled apoptotic response provides an essential mechanism, enabling corals to respond to global warming and ocean acidification. However, the molecules involved and their functions are still unclear. To better characterize the apoptotic response in basal metazoans, we studied the expression profiles of selected genes that encode for putative pro- and anti-apoptotic mediators in the coral Stylophora pistillata under thermal stress and bleaching conditions. Upon thermal stress, as attested by the elevation of the heat-shock protein gene HSP70’s mRNA levels, the expression of all studied genes, including caspase, Bcl-2, Bax, APAF-1 and BI-1, peaked at 6-24 h of thermal stress (hts) and declined at 72 hts. Adversely, the expression levels of the survivin gene showed a shifted pattern, with elevation at 48-72 hts and a return to basal levels at 168 hts. Overall, we show the quantitative anti-apoptotic traits of the coral Bcl-2 protein, which resemble those of its mammalian counterpart. Altogether, our results highlight the similarities between apoptotic networks operating in simple metazoans and in higher animals and clearly demonstrate the activation of pro-cell survival regulators at early stages of the apoptotic response, contributing to the decline of apoptosis and the acclimation to chronic stress.

Objective measures, sensors and computational techniques for stress recognition and classification: a survey.

PubMed

Sharma, Nandita; Gedeon, Tom

2012-12-01

Stress is a major growing concern in our day and age adversely impacting both individuals and society. Stress research has a wide range of benefits from improving personal operations, learning, and increasing work productivity to benefiting society - making it an interesting and socially beneficial area of research. This survey reviews sensors that have been used to measure stress and investigates techniques for modelling stress. It discusses non-invasive and unobtrusive sensors for measuring computed stress, a term we coin in the paper. Sensors that do not impede everyday activities that could be used by those who would like to monitor stress levels on a regular basis (e.g. vehicle drivers, patients with illnesses linked to stress) is the focus of the discussion. Computational techniques have the capacity to determine optimal sensor fusion and automate data analysis for stress recognition and classification. Several computational techniques have been developed to model stress based on techniques such as Bayesian networks, artificial neural networks, and support vector machines, which this survey investigates. The survey concludes with a summary and provides possible directions for further computational stress research. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Stress, coping, and depression: testing new hypotheses in a prospectively studied general population sample of U.S. born Whites and Blacks

PubMed Central

Keyes, K.M.; Barnes, D.; Bates, L.M.

2010-01-01

The scarcity of empirically supported explanations for the Black/White prevalence difference in depression in the U.S. is a conspicuous gap in the literature. Recent evidence suggests that the paradoxical observation of decreased risk of depression but elevated rates of physical illness among Blacks in the U.S. compared with Whites may be accounted for by the use of coping behaviors (e.g., alcohol and nicotine consumption, overeating) among Blacks exposed to high stress levels. Such coping behaviors may mitigate deleterious effects of stressful exposures on mental health while increasing the risk of physical ailments. The racial patterning in mental and physical health outcomes could therefore be explained by this mechanism if a) these behaviors were more prevalent among Blacks than Whites and/or b) the effect of these behavioral responses to stress was differential by race. The present study challenges this hypothesis using longitudinal, nationally-representative data with comprehensive DSM-IV diagnoses. Data are drawn from 34,653 individuals sampled in Waves 1 (2001-2002) and 2 (2004-2005) as part of the US National Epidemiologic Survey on Alcohol and Related Conditions. Results showed that a) Blacks were less likely to engage in alcohol or nicotine consumption at low, moderate, and high levels of stress compared to Whites, and b) there was a significant three-way interaction between race, stress, and coping behavior for BMI only (F=2.11, df=12, p=0.03), but, contrary to the hypothesis, elevated BMI was protective against depression in Blacks at low, not high, levels of stress. Further, engagement in unhealthy behaviors, especially at pathological levels, did not protect against depression in Blacks or in Whites. In sum, the impact of stress and coping processes on depression do not appear to operate differently in Blacks versus Whites. Further research testing innovative hypotheses that would explain the difference in Black/White depression prevalence is warranted. PMID:21227557

Stress, coping, and depression: testing a new hypothesis in a prospectively studied general population sample of U.S.-born Whites and Blacks.

PubMed

Keyes, K M; Barnes, David M; Bates, L M

2011-03-01

The scarcity of empirically supported explanations for the Black/White prevalence difference in depression in the U.S. is a conspicuous gap in the literature. Recent evidence suggests that the paradoxical observation of decreased risk of depression but elevated rates of physical illness among Blacks in the U.S. compared with Whites may be accounted for by the use of coping behaviors (e.g., alcohol and nicotine consumption, overeating) among Blacks exposed to high stress levels. Such coping behaviors may mitigate deleterious effects of stressful exposures on mental health while increasing the risk of physical ailments. The racial patterning in mental and physical health outcomes could therefore be explained by this mechanism if a) these behaviors were more prevalent among Blacks than Whites and/or b) the effect of these behavioral responses to stress was differential by race. The present study challenges this hypothesis using longitudinal, nationally-representative data with comprehensive DSM-IV diagnoses. Data are drawn from 34,653 individuals sampled in Waves 1 (2001-2002) and 2 (2004-2005) as part of the US National Epidemiologic Survey on Alcohol and Related Conditions. Results showed that a) Blacks were less likely to engage in alcohol or nicotine consumption at low, moderate, and high levels of stress compared to Whites, and b) there was a significant three-way interaction between race, stress, and coping behavior for BMI only (F = 2.11, df = 12, p = 0.03), but, contrary to the hypothesis, elevated BMI was protective against depression in Blacks at low, not high, levels of stress. Further, engagement in unhealthy behaviors, especially at pathological levels, did not protect against depression in Blacks or in Whites. In sum, the impact of stress and coping processes on depression does not appear to operate differently in Blacks versus Whites. Further research testing innovative hypotheses that would explain the difference in Black/White depression prevalence is warranted. Copyright © 2010 Elsevier Ltd. All rights reserved.

Generalized recursion relations for correlators in the gauge-gravity correspondence.

PubMed

Raju, Suvrat

2011-03-04

We show that a generalization of the Britto-Cachazo-Feng-Witten recursion relations gives a new and efficient method of computing correlation functions of the stress tensor or conserved currents in conformal field theories with an (d+1)-dimensional anti-de Sitter space dual, for d≥4, in the limit where the bulk theory is approximated by tree-level Yang-Mills theory or gravity. In supersymmetric theories, additional correlators of operators that live in the same multiplet as a conserved current or stress tensor can be computed by these means.

12 CFR 615.5141 - Stress tests for mortgage securities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Stress tests for mortgage securities. 615.5141... AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Investment Management § 615.5141 Stress... stress test. You must perform stress tests to determine how interest rate changes will affect the...

12 CFR 615.5141 - Stress tests for mortgage securities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Investment Management § 615.5141 Stress... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Stress tests for mortgage securities. 615.5141... stress test. You must perform stress tests to determine how interest rate changes will affect the...

12 CFR 615.5141 - Stress tests for mortgage securities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Investment Management § 615.5141 Stress... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Stress tests for mortgage securities. 615.5141... stress test. You must perform stress tests to determine how interest rate changes will affect the...

12 CFR 615.5141 - Stress tests for mortgage securities.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Investment Management § 615.5141 Stress... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Stress tests for mortgage securities. 615.5141... stress test. You must perform stress tests to determine how interest rate changes will affect the...

Influence of preoperative oral feeding on stress response after resection for colon cancer.

PubMed

Zelić, Marko; Stimac, Davor; Mendrila, Davor; Tokmadžić, Vlatka Sotošek; Fišić, Elizabeta; Uravić, Miljenko; Sustić, Alan

2012-01-01

Preoperative management involves patients fasting from midnight on the evening prior to surgery. Fasting period is often long enough to change the metabolic condition of the patient which increases perioperative stress response. That could have a detrimental effect on clinical outcome. The aim of the present study was to investigate the possible effects of carbohydrate-rich beverage on stress response after colon resection. Randomized and double blinded study included 40 patients with colon, upper rectal or rectosigmoid cancer. Investigated group received a carbohydrate-rich beverage the day before and two hours before surgery. In the control group patients were in the standard preoperative regime: nothing by mouth from the evening prior to operation. Peripheral blood was sampled 24h before surgery, at the day of the surgery, and 6, 24 and 48h postoperatively. Colonic resection in both groups caused a significant increase in serum interleukin 6 (IL-6) levels 6, 24 and 48h after the operation. Increase was more evident and statistically significant in the group with fasting protocol. More significant increase of interleukin 10 (IL-10) occurred in patients who received preoperative nutrition. Smaller increase in IL-6 and higher in IL- 10 are indicators of reduced perioperative stress.

1800 MHz mobile phone irradiation induced oxidative and nitrosative stress leads to p53 dependent Bax mediated testicular apoptosis in mice, Mus musculus.

PubMed

Shahin, Saba; Singh, Surya P; Chaturvedi, Chandra M

2018-09-01

Present study was carried out to investigate the effect of long-term mobile phone radiation exposure in different operative modes (Dialing, Receiving, and Stand-by) on immature male mice. Three-week old male mice were exposed to mobile phone (1800 MHz) radiation for 3 hr/day for 120 days in different operative modes. To check the changes/alteration in testicular histoarchitecture and serum testosterone level, HE staining and ELISA was performed respectively. Further, we have checked the redox status (ROS, NO, MDA level, and antioxidant enzymes: SOD, CAT, and GPx) by biochemical estimation, alteration in the expression of pro-apoptotic proteins (p53 and Bax), active executioner caspase-3, full length/uncleaved PARP-1 (DNA repair enzyme), anti-apoptotic proteins (Bcl-2 and Bcl-x L ) in testes by immunofluorescence and cytosolic cytochrome-c by Western blot. Decreased seminiferous tubule diameter, sperm count, and viability along with increased germ cells apoptosis and decreased serum testosterone level, was observed in the testes of all the mobile phone exposed mice compared with control. We also observed that, mobile phone radiation exposure in all the three different operative modes alters the testicular redox status via increasing ROS, NO, and MDA level, and decreasing antioxidant enzymes levels leading to enhanced apoptosis of testicular cells by increasing the expression of pro-apoptotic and apoptotic proteins along with decreasing the expression of anti-apoptotic protein. On the basis of results, it is conclude that long-term mobile phone radiation exposure induced oxidative stress leads to apoptosis of testicular cells and thus impairs testicular function. © 2018 Wiley Periodicals, Inc.

Influence of Mild Traumatic Brain Injury (TBI) and Posttraumatic Stress Disorder (PTSD) on Pain Intensity Levels in OEF/OIF/OND Veterans.

PubMed

Stojanovic, Milan P; Fonda, Jennifer; Fortier, Catherine Brawn; Higgins, Diana M; Rudolph, James L; Milberg, William P; McGlinchey, Regina E

2016-11-01

Mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) are common among US veterans of Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND). We postulated that these injuries may modulate pain processing in these individuals and affect their subjective pain levels. Cross-sectional. 310 deployed service members of OEF/OIF/OND without a lifetime history of moderate or severe TBI were included in this study. All participants completed a comprehensive evaluation for Blast Exposure, mTBI, PTSD, and Pain Levels. The Boston Assessment of TBI-Lifetime Version (BAT-L) was used to assess blast exposure and potential brain injury during military service. The Clinician-Administered PTSD Scale (CAPS) characterized presence and severity of PTSD. The Visual Analog Scale (VAS) was used to assess pain intensity over the previous month before the interview, with higher scores indicative of worse pain. Statistical analysis was performed by ANOVA and results were adjusted for co-morbidities, clinical characteristics and demographic data. In comparison to control participants (veterans without mTBI or current PTSD), veterans with both current PTSD and mTBI reported the highest pain intensity levels, followed by veterans with PTSD only (P < 0.0001 and P = 0.0005, respectively). Pain levels in veterans with mTBI only were comparable to control participants. Comorbid PTSD and mTBI is associated with increased self-reported pain intensity. mTBI alone was not associated with increased pain. Published by Oxford University Press on behalf of the American Academy of Pain Medicine 2016. This work is written by US Government employees and is in the public domain in the US.

Evaluation of the Operational Stress Control and Readiness (OSCAR) Program

DTIC Science & Technology

2015-01-01

Responding to Combat Stress Reactions . . . . . . . . . . . . . . . . . . . . 33 4.4. Team Leaders’ View of Stigma Associated with Combat Stress...leaders’ perceptions of OSCAR’s impact on attitudes toward stress response and recovery; unit cohesion and morale; stigma around mental health and...Continuum, a tool for identi- fying combat stress problems of varying severity, and Combat and Operational Stress First Aid (COSFA), a psychological

National Airspace System Plan: Facilities, Equipment, Associated Development and Other Capital Needs

DTIC Science & Technology

1989-09-01

yes include: 0 Air carrier routes and services will reflect a * Having an operating National Airspace System better balance between trip frequency and... balanced workload. " A major improvement and integration of the FAA communications system will be imple- 0 Reliable equipment, which minimizes the stress...them in this will lead to the development of production level balancing sector staffing levels, specifications in FY 97. * Trial flight plan function

Prediction of endocrine stress reactions by means of personality variables.

PubMed

de Leeuwe, J N; Hentschel, U; Tavenier, R; Edelbroek, P

1992-06-01

The study examined the predictability of endocrine stress indicators on the basis of personality measures. The subjects were 83 computer operators (63 men, 20 women; mean age 28 years) who by means of an experimental situation were confronted with a mild stressor (a cognitive two-channel task with a high information load). Using scores on personality questionnaires (comprising scales for defense mechanisms, neuroticism, and 2 achievement motivation variables), subjects were classified into extreme groups of stress-resistant (17 subjects) versus nonstress-resistant (13 subjects). Immediately after the experiment blood samples were taken to assay the norepinephrine metabolites plasma-free 3-methoxy-4-hydroxy-phenylglycol (MHPG) and MHPG sulfate (MHPG.SO4), which formed the dependent variables. Personality measures and endocrine stress indicators were until the final analysis of the data kept apart by a double-blind strategy. A significant difference was noted in the MHPG level between the stress-resistant and the nonstress-resistant group. The value and applicability of these results for stress prevention is discussed.

A demonstration of mitigation of environmentally-assisted cracking by the application of a tensile overload

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

James, L.A.

1997-02-01

Environmentally-assisted cracking (EAC) of low-alloy steels in high-temperature aqueous environments typical of those employed in light-water reactor (LWR) systems has been a subject of considerable interest since the pioneering work of Kondo et al demonstrated significantly higher fatigue crack propagation (FCP) rates in water than would be expected in an air environment under similar conditions. Here, environmentally-assisted cracking (EAC) of low-alloy steels in elevated temperature aqueous environments is readily observed in many laboratory experiments conducted in autoclaves, yet the observation of EAC in actual components operating in the same environments is quite rare. Mass transport of sulfides from the crackmore » enclave by diffusion and convection occurring in operating components provides one plausible explanation to this apparent paradox. Another contribution to EAC mitigation may also arise from the non-constant stress amplitudes typical for many operating components. This paper provides a demonstration of how a single tensile overload to 40% above a steady-state maximum fatigue stress can retard subsequent crack growth at the steady-state level for a sufficient period of time that diffusion mass transport can reduce the crack-tip sulfide concentration to a level below that necessary to sustain EAC.« less

Decreasing Free Radicals Level on High Risk Person After Vitamin C and E Supplement Treatment

NASA Astrophysics Data System (ADS)

Sitorus, M. S.; Anggraini, D. R.; Hidayat

2017-03-01

Has become a global issue that the increase in global warming mainly caused by high air pollution levels which are donated by motor vehicle emissions. As a rapidly developing country, Indonesia becomes vulnerable to health problems related to air pollution. Excessive free radicals that is produced by air pollution can initiate stress oxidative. Already known that, stress oxidative trigger many health problems. Vitamin C and E is a non enzymatic antioxidant that can neutralize free radicals. This study aims to investigate the decreasing free radicals level by administering vitamin C and E. This research using pre and post experimental design study. There are 24 operators gasoline station Pertamina as samples, with an average age of 26 years. The samples were divided into 4 groups. Group 1 (control), group 2, were given vitamin C doses of 500mg / day, group 3 was given vitamin E doses of 250 IU / day and the group 4 was given a combination of vitamins C and E. The treatment was given for 30 days. Free radicals level is obtained from malonaldehyde (MDA) level by spectrophotometer. Before treatment the average of MDA level is 5.540 µm. After the treatment, MDA is significantly decreased become 3.992 µm (T-test, sig<0.05). This result can be used as a sign of side affect of air pollutant in the operator SPBU. As reminding to protect the employee with safety aid and supplement.

49 CFR 192.609 - Change in class location: Required study.

Code of Federal Regulations, 2010 CFR

2010-10-01

... class location for a segment of an existing steel pipeline operating at hoop stress that is more than 40 percent of SMYS, or indicates that the hoop stress corresponding to the established maximum allowable... actual operating pressure and the corresponding operating hoop stress, taking pressure gradient into...

49 CFR 192.609 - Change in class location: Required study.

Code of Federal Regulations, 2012 CFR

2012-10-01

... class location for a segment of an existing steel pipeline operating at hoop stress that is more than 40 percent of SMYS, or indicates that the hoop stress corresponding to the established maximum allowable... actual operating pressure and the corresponding operating hoop stress, taking pressure gradient into...

49 CFR 192.609 - Change in class location: Required study.

Code of Federal Regulations, 2011 CFR

2011-10-01

... class location for a segment of an existing steel pipeline operating at hoop stress that is more than 40 percent of SMYS, or indicates that the hoop stress corresponding to the established maximum allowable... actual operating pressure and the corresponding operating hoop stress, taking pressure gradient into...

What Is Better Than Coulomb Failure Stress? A Ranking of Scalar Static Stress Triggering Mechanisms from 105 Mainshock-Aftershock Pairs

NASA Astrophysics Data System (ADS)

Meade, Brendan J.; DeVries, Phoebe M. R.; Faller, Jeremy; Viegas, Fernanda; Wattenberg, Martin

2017-11-01

Aftershocks may be triggered by the stresses generated by preceding mainshocks. The temporal frequency and maximum size of aftershocks are well described by the empirical Omori and Bath laws, but spatial patterns are more difficult to forecast. Coulomb failure stress is perhaps the most common criterion invoked to explain spatial distributions of aftershocks. Here we consider the spatial relationship between patterns of aftershocks and a comprehensive list of 38 static elastic scalar metrics of stress (including stress tensor invariants, maximum shear stress, and Coulomb failure stress) from 213 coseismic slip distributions worldwide. The rates of true-positive and false-positive classification of regions with and without aftershocks are assessed with receiver operating characteristic analysis. We infer that the stress metrics that are most consistent with observed aftershock locations are maximum shear stress and the magnitude of the second and third invariants of the stress tensor. These metrics are significantly better than random assignment at a significance level of 0.005 in over 80% of the slip distributions. In contrast, the widely used Coulomb failure stress criterion is distinguishable from random assignment in only 51-64% of the slip distributions. These results suggest that a number of alternative scalar metrics are better predictors of aftershock locations than classic Coulomb failure stress change.

Chronic inflammation aggravates metabolic disorders of hepatic fatty acids in high-fat diet-induced obese mice

PubMed Central

Zhao, Lei; Zhong, Shan; Qu, Haiyang; Xie, Yunxia; Cao, Zhennan; Li, Qing; Yang, Ping; Varghese, Zac; Moorhead, John F.; Chen, Yaxi; Ruan, Xiong Z.

2015-01-01

The prevalence of nonalcoholic fatty liver disease (NAFLD) increases with increasing body mass index (BMI). However, approximately 40–50% of obese adults do not develop hepatic steatosis. The level of inflammatory biomarkers is higher in obese subjects with NAFLD compared to BMI-matched subjects without hepatic steatosis. We used a casein injection in high-fat diet (HFD)-fed C57BL/6J mice to induce inflammatory stress. Although mice on a HFD exhibited apparent phenotypes of obesity and hyperlipidemia regardless of exposure to casein injection, only the HFD+Casein mice showed increased hepatic vacuolar degeneration accompanied with elevated inflammatory cytokines in the liver and serum, compared to mice on a normal chow diet. The expression of genes related to hepatic fatty acid synthesis and oxidation were upregulated in the HFD-only mice. The casein injection further increased baseline levels of lipogenic genes and decreased the levels of oxidative genes in HFD-only mice. Inflammatory stress induced both oxidative stress and endoplasmic reticulum stress in HFD-fed mice livers. We conclude that chronic inflammation precedes hepatic steatosis by disrupting the balance between fatty acid synthesis and oxidation in the livers of HFD-fed obese mice. This mechanism may operate in obese individuals with chronic inflammation, thus making them more prone to NAFLD. PMID:25974206

Evaluation of immune and stress status in harbour porpoises (Phocoena phocoena): can hormones and mRNA expression levels serve as indicators to assess stress?

PubMed Central

2013-01-01

Background The harbour porpoise is exposed to increasing pressure caused by anthropogenic activities in its marine environment. Numerous offshore wind farms are planned or under construction in the North and Baltic Seas, which will increase underwater noise during both construction and operation. A better understanding of how anthropogenic impacts affect the behaviour, health, endocrinology, immunology and physiology of the animals is thus needed. The present study compares levels of stress hormones and mRNA expression of cytokines and acute-phase proteins in blood samples of harbour porpoises exposed to different levels of stress during handling, in rehabilitation or permanent human care. Free-ranging harbour porpoises, incidentally caught in pound nets in Denmark, were compared to harbour porpoises in rehabilitation at SOS Dolfijn in Harderwijk, the Netherlands, and individuals permanently kept in human care in the Dolfinarium Harderwijk and Fjord & Belt Kerteminde, Denmark. Blood samples were investigated for catecholamines, adrenaline, noradrenaline and dopamine, as well as for adrenocorticotropic hormone (ACTH), cortisol, metanephrine and normetanephrine. mRNA expression levels of relevant cell mediators (cytokines IL-10 and TNFα, acute-phase proteins haptoglobin and C-reactive protein and the heat shock protein HSP70) were measured using real-time PCR. Results Biomarker expression levels varied between free-ranging animals and porpoises in human care. Hormone and cytokine ranges showed correlations to each other and to the health status of investigated harbour porpoises. Hormone concentrations were higher in free-ranging harbour porpoises than in animals in human care. Adrenaline can be used as a parameter for the initial reaction to acute stress situations; noradrenaline, dopamine, ACTH and cortisol are more likely indicators for the following minutes of acute stress. There is evidence for different correlations between production of normetanephrine, metanephrine, cortisol and the expression of IL-10, HSP70 and haptoglobin. Conclusions The expression patterns of the selected molecular biomarkers of the immune system are promising to reflect the health and immune status of the harbour porpoise under different levels of stress. PMID:23866055

Interdependency of Reactive Oxygen Species generating and scavenging system in salt sensitive and salt tolerant cultivars of rice.

PubMed

Kaur, Navdeep; Dhawan, Manish; Sharma, Isha; Pati, Pratap Kumar

2016-06-10

Salinity stress is a major constrain in the global rice production and hence serious efforts are being undertaken towards deciphering its remedial strategies. The comparative analysis of differential response of salt sensitive and salt tolerant lines is a judicious approach to obtain essential clues towards understanding the acquisition of salinity tolerance in rice plants. However, adaptation to salt stress is a fairly complex process and operates through different mechanisms. Among various mechanisms involved, the reactive oxygen species mediated salinity tolerance is believed to be critical as it evokes cascade of responses related to stress tolerance. In this background, the present paper for the first time evaluates the ROS generating and the scavenging system in tandem in both salt sensitive and salt tolerant cultivars of rice for getting better insight into salinity stress adaptation. Comparative analysis of ROS indicates the higher level of hydrogen peroxide (H2O2) and lower level of superoxide ions (O(2-)) in the salt tolerant as compared to salt sensitive cultivars. Specific activity of ROS generating enzyme, NADPH oxidase was also found to be more in the tolerant cultivars. Further, activities of various enzymes involved in enzymatic and non enzymatic antioxidant defence system were mostly higher in tolerant cultivars. The transcript level analysis of antioxidant enzymes were in alignment with the enzymatic activity. Other stress markers like proline were observed to be higher in tolerant varieties whereas, the level of malondialdehyde (MDA) equivalents and chlorophyll content were estimated to be more in sensitive. The present study showed significant differences in the level of ROS production and antioxidant enzymes activities among sensitive and tolerant cultivars, suggesting their possible role in providing natural salt tolerance to selected cultivars of rice. Our study demonstrates that the cellular machinery for ROS production and scavenging system works in an interdependent manner to offer better salt stress adaptation in rice. The present work further highlights that the elevated level of H2O2 which is considered as a key determinant for conferring salt stress tolerance to rice might have originated through an alternative route of photocatalytic activity of chlorophyll.

Epigallocatechin-3-gallate protects against hepatic ischaemia-reperfusion injury by reducing oxidative stress and apoptotic cell death.

PubMed

Tak, Eunyoung; Park, Gil-Chun; Kim, Seok-Hwan; Jun, Dae Young; Lee, Jooyoung; Hwang, Shin; Song, Gi-Won; Lee, Sung-Gyu

2016-12-01

Objective To investigate the protective effects of epigallocatechin-3-gallate (EGCG), a major polyphenol source in green tea, against hepatic ischaemia-reperfusion injury in mice. Methods The partial hepatic ischaemia-reperfusion injury model was created by employing the hanging-weight method in C57BL/6 male mice. EGCG (50 mg/kg) was administered via an intraperitoneal injection 45 min before performing the reperfusion. A number of markers of inflammation, oxidative stress, apoptosis and liver injury were measured after the ischaemia-reperfusion injury had been induced. Results The treatment groups were: sham-operated (Sham, n = 10), hepatic ischaemia-reperfusion injury (IR, n = 10), and EGCG with ischaemia-reperfusion injury (EGCG-treated IR, n = 10). Hepatic ischaemia-reperfusion injury increased the levels of biochemical and histological markers of liver injury, increased the levels of malondialdehyde, reduced the glutathione/oxidized glutathione ratio, increased the levels of oxidative stress and lipid peroxidation markers, decreased B-cell lymphoma 2 levels, and increased the levels of Bax, cytochrome c, cleaved caspase-3, and cleaved caspase-9. Pretreatment with EGCG ameliorated all of these changes. Conclusion The antioxidant and antiapoptotic effects of EGCG protected against hepatic ischaemia-reperfusion injury in mice.

Epigallocatechin-3-gallate protects against hepatic ischaemia–reperfusion injury by reducing oxidative stress and apoptotic cell death

PubMed Central

Tak, Eunyoung; Park, Gil-Chun; Kim, Seok-Hwan; Jun, Dae Young; Lee, Jooyoung; Hwang, Shin; Lee, Sung-Gyu

2016-01-01

Objective To investigate the protective effects of epigallocatechin-3-gallate (EGCG), a major polyphenol source in green tea, against hepatic ischaemia–reperfusion injury in mice. Methods The partial hepatic ischaemia–reperfusion injury model was created by employing the hanging-weight method in C57BL/6 male mice. EGCG (50 mg/kg) was administered via an intraperitoneal injection 45 min before performing the reperfusion. A number of markers of inflammation, oxidative stress, apoptosis and liver injury were measured after the ischaemia–reperfusion injury had been induced. Results The treatment groups were: sham-operated (Sham, n = 10), hepatic ischaemia–reperfusion injury (IR, n = 10), and EGCG with ischaemia–reperfusion injury (EGCG-treated IR, n = 10). Hepatic ischaemia–reperfusion injury increased the levels of biochemical and histological markers of liver injury, increased the levels of malondialdehyde, reduced the glutathione/oxidized glutathione ratio, increased the levels of oxidative stress and lipid peroxidation markers, decreased B-cell lymphoma 2 levels, and increased the levels of Bax, cytochrome c, cleaved caspase-3, and cleaved caspase-9. Pretreatment with EGCG ameliorated all of these changes. Conclusion The antioxidant and antiapoptotic effects of EGCG protected against hepatic ischaemia–reperfusion injury in mice. PMID:27807255

49 CFR 194.103 - Significant and substantial harm; operator's statement.

Code of Federal Regulations, 2010 CFR

2010-10-01

... a stress level greater than 50 percent of the specified minimum yield strength of the pipe, (4) Is located within a 5 mile (8 kilometer) radius of potentially affected public drinking water intakes and could reasonably be expected to reach public drinking water intakes, or (5) Is located within a 1 mile...

49 CFR 194.103 - Significant and substantial harm; operator's statement.

Code of Federal Regulations, 2011 CFR

2011-10-01

... a stress level greater than 50 percent of the specified minimum yield strength of the pipe, (4) Is located within a 5 mile (8 kilometer) radius of potentially affected public drinking water intakes and could reasonably be expected to reach public drinking water intakes, or (5) Is located within a 1 mile...

Rubber dam use less stressful for children and dentists.

PubMed

Innes, Nicola

2012-06-01

Randomised controlled trial, single centre and operator. 72 patients (6-16 years) assessed as compliant, with no allergies, not on significant medication were divided into two groups by 'drawing sealed lots'. 234 fully erupted teeth were sealed. Molars and/or premolars were sealed dependant on age. Teeth were pre-cleaned with prophy paste. In the controls, teeth were isolated with buccal and lingual cotton rolls and salivary ejector in the intervention group a rubber dam was used. The same etching, rinsing and placement protocol was used in both arms. Outcomes were: patients' subjective measures of pain using a visual analogue scale; blood pressure (before and after treatment), breath rate, pulse rate and skin resistance at five time points. The operator's pulse rate was measured and they completed a questionnaire on subjective mental and physical stress following treatment. Treatment times were recorded. The breath rate was significantly (P < 0.05) lower and the skin resistance level was significantly higher during treatment with rubber dam compared to the control group. Subjective pain perception was significantly lower for the test group. The treatment time needed for the fissure sealing procedure was 12.4% less in the test group. The authors state; '... in the hands of an experienced dentist, isolation with rubber dam is less stressful for children and adolescents than isolation with cotton rolls, and can save valuable treatment time.' The operator's stress measures were lower with rubber dam and treatment time was reduced.

Enhanced susceptibility to periodontitis in an animal model of depression: reversed by chronic treatment with the anti-depressant tianeptine.

PubMed

Breivik, Torbjørn; Gundersen, Yngvar; Myhrer, Trond; Fonnum, Frode; Osmundsen, Harald; Murison, Robert; Gjermo, Per; von Hörsten, Stephan; Opstad, Per Kristian

2006-07-01

To test the hypothesis that the olfactory bulbectomy model of depression in rats could influence susceptibility to ligature-induced periodontitis, and that chronic treatment with the anti-depressant drug tianeptine could attenuate this effect. Tianeptine was given twice daily (10 mg/kg, i.p.) during the entire experiment, starting 29 days before induction of olfactory bulbectomy and periodontitis. Olfactory bulbectomized (OB) rats and sham-operated rats were given saline in a similar manner. Periodontal disease was assessed when the ligatures had been in place for 21 days. Two hours before decapitation, rats were injected with lipopolysaccharide (LPS;100 microg/kg, i.p.) to induce a robust immune and stress response. Compared with sham-operated controls, OB rats developed significantly more periodontal bone loss, exhibited characteristic behavioural responses in a novel open field test, and showed a decreased expression of glucocorticoid receptors (GRs) in the hippocampus. LPS provoked a significantly larger increase in circulating levels of the stress hormone corticosterone and the cytokine transformation growth factor (TGF)-1beta but smaller tumour necrosis factor (TNF)-alpha levels. Tianeptine treatment of OB rats significantly inhibited peridodontal bone loss, normalized behavioural responses, enhanced TGF-1beta levels, and abolished TNF-alpha decrease, but did not attenuate the increased corticosterone response and the decreased hippocampal GR expression. These experimental results are consistent with an emerging literature showing that life stress, anxiety, depression, pathological grief, and poor coping behaviour may dysregulate regulatory mechanisms within the brain involved in immune regulation, and thereby alter immune responses and influence the susceptibility/resistance to inflammatory disorders.

Behavioral and biological interactions with small groups in confined microsocieties

NASA Technical Reports Server (NTRS)

Brady, J. V.; Emurian, H. H.

1982-01-01

Requirements for high levels of human performance in the unfamiliar and stressful environments associated with space missions necessitate the development of research-based technological procedures for maximizing the probability of effective functioning at all levels of personnel participation. Where the successful accomplishment of such missions requires the coordinated contributions of several individuals collectively identified with the achievement of a common objective, the conditions for characterizing a team, crew, or functional group are operationally defined. For the most part, studies of group performances under operational conditions which emphasize relatively long exposure to extended mission environments have been limited by the constraints imposed on experimental manipulations to identify critical effectiveness factors. On the other hand, laboratory studies involving relatively brief exposures to contrived task situations have been considered of questionable generality to operational settings requiring realistic group objectives.

Investigation into ammonia stress on Cyperus alternifolius and its impact on nutrient removal in microcosm experiments.

PubMed

Tao, Wendong; Han, Jianqiu; Li, Hanyan

2015-11-01

Ammonia stress on plants has been investigated at discrete ammonia concentrations in constructed wetlands. This study introduced a Gaussian model to simulate the kinetics of ammonia stress and investigated reversible and irreversible ammonia stress on Cyperus alternifolius in wetland-like microcosms. Ammonia stress on plant weight increase and oxygen release potential started at weekly ammonia concentrations of 27 and 28 mg N/L, reached 50% inhibition at 178 and 158 mg N/L, and resulted in lethal effects at 311 and 303 mg N/L, respectively. The stress of one-time ammonia concentrations up to 400 mg N/L could be reversible. Ammonia concentrations constantly above 219 mg N/L exerted irreversible stress. In the microcosms with ammonia concentrations above the 50% inhibition levels, plants played a minor role in nitrogen removal. Nitrogen removal performance was not affected considerably by ammonia stress. Orthophosphate removal was suppressed by ammonia stress due to less plant uptake. Design and operation of constructed wetlands should consider wastewater ammonia concentration so that the integrity of constructed wetland ecosystems can be maintained. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rigid patterns of effortful choice behavior after acute stress in rats.

PubMed

Hart, Evan E; Stolyarova, Alexandra; Conoscenti, Michael A; Minor, Thomas R; Izquierdo, Alicia

2017-01-01

Physical effort is a common cost of acquiring rewards, and decreased effort is a feature of many neuropsychiatric disorders. Stress affects performance on several tests of cognition and decision making in both humans and nonhumans. Only a few recent reports show impairing effects of stress in operant tasks involving effort and cognitive flexibility. Brain regions affected by stress, such as the medial prefrontal cortex and amygdala, are also implicated in mediating effortful choices. Here, we assessed effort-based decision making after an acute stress procedure known to induce persistent impairment in shuttle escape and elevated plasma corticosterone. In these animals, we also probed levels of polysialyted neural cell adhesion molecule (PSA-NCAM), a marker of structural plasticity, in medial frontal cortex and amygdala. We found that animals that consistently worked for high magnitude rewards continued to do so, even after acute shock stress. We also found that PSA-NCAM was increased in both regions after effortful choice experience but not after shock stress alone. These findings are discussed with reference to the existing broad literature on cognitive effects of stress and in the context of how acute stress may bias effortful decisions to a rigid pattern of responding.

Remote detection of canopy water stress in coniferous forests using the NS001 Thematic Mapper Simulator and the thermal infrared multispectral scanner

NASA Technical Reports Server (NTRS)

Pierce, Lars L.; Running, Steven W.; Riggs, George A.

1990-01-01

Water stress was induced in two coniferous forest stands in West Germany by severing tree sapwood. Leaf water potential, Psi(L), measurements indicated that maximum, naturally occurring levels of water stress developed in the stressed plots while control plots exhibited natural diurnal trends. Images of each site were obtained with the Thematic Mapper Simulator (NS001) and the Thermal Infrared Multispectral Scanner (TIMS) 12 to 15 days after stress induction. NS001 bands 2 to 6, NS001 indices combining bands 4 and 6, and NS001 and TIMS thermal bands showed significant radiance differences between stressed and control plots when large differences in Psi(L) and relative water content (RWC) existed during the morning overflights at Munich. However, the NS001 and TIMS sensors could not detect the slightly smaller differences in Psi(L) and RWC during the Munich afternoon and Frankfurt overflights. The results suggest that routine detection of canopy water stress under operational conditions is difficult utilizing current sensor technology.

Statics and buckling problems of aircraft structurally-anisotropic composite panels with the influence of production technology

NASA Astrophysics Data System (ADS)

Gavva, L. M.; Endogur, A. I.

2018-02-01

The mathematical model relations for stress-strain state and for buckling investigation of structurally-anisotropic panels made of composite materials are presented. The mathematical model of stiffening rib being torsioned under one-side contact with the skin is refined. One takes into account the influence of panel production technology: residual thermal stresses and reinforcing fibers preliminary tension. The resolved eight order equation and natural boundary conditions are obtained with variation Lagrange procedure. Exact analytical solutions for edge problems are considered. Computer program package is developed using operating MATLAB environment. The influence of the structure parameters on the level of stresses, displacements, of critical buckling forces for bending and for torsion modes has analyzed.

Surgical treatment of refractory tibial stress fractures in elite dancers: a case series.

PubMed

Miyamoto, Ryan G; Dhotar, Herman S; Rose, Donald J; Egol, Kenneth

2009-06-01

Treatment of tibial stress fractures in elite dancers is centered on rest and activity modification. Surgical intervention in refractory cases has important implications affecting the dancers' careers. Refractory tibial stress fractures in dancers can be treated successfully with drilling and bone grafting or intramedullary nailing. Case series; Level of evidence, 4. Between 1992 and 2006, 1757 dancers were evaluated at a dance medicine clinic; 24 dancers (1.4%) had 31 tibial stress fractures. Of that subset, 7 (29.2%) elite dancers with 8 tibial stress fractures were treated operatively with either intramedullary nailing or drilling and bone grafting. Six of the patients were followed up closely until they were able to return to dance. One patient was available only for follow-up phone interview. Data concerning their preoperative treatment regimens, operative procedures, clinical union, radiographic union, and time until return to dance were recorded and analyzed. The mean age of the surgical patients at the time of stress fracture was 22.6 years. The mean duration of preoperative symptoms before surgical intervention was 25.8 months. Four of the dancers were male and 3 were female. All had failed nonoperative treatment regimens. Five patients (5 tibias) underwent drilling and bone grafting of the lesion, and 2 patients (3 tibias) with completed fractures or multiple refractory stress fractures underwent intramedullary nailing. Clinical union was achieved at a mean of 6 weeks and radiographic union at 5.1 months. Return to full dance activity was at an average of 6.5 months postoperatively. Surgical intervention for tibial stress fractures in dancers who have not responded to nonoperative management allowed for resolution of symptoms and return to dancing with minimal morbidity.

Thermal management methods for compact high power LED arrays

NASA Astrophysics Data System (ADS)

Christensen, Adam; Ha, Minseok; Graham, Samuel

2007-09-01

The package and system level temperature distributions of a high power (>1W) light emitting diode (LED) array has been investigated using numerical heat flow models. For this analysis, a thermal resistor network model was combined with a 3D finite element submodel of an LED structure to predict system and die level temperatures. The impact of LED array density, LED power density, and active versus passive cooling methods on device operation were calculated. In order to help understand the role of various thermal resistances in cooling such compact arrays, the thermal resistance network was analyzed in order to estimate the contributions from materials as well as active and passive cooling schemes. An analysis of thermal stresses and residual stresses in the die are also calculated based on power dissipation and convection heat transfer coefficients. Results show that the thermal stress in the GaN layer are compressive which can impact the band gap and performance of the LEDs.

Relation Between Residual and Hoop Stresses and Rolling Bearing Fatigue Life

NASA Technical Reports Server (NTRS)

Oswald, Fred B.; Zaretsky, Erwin V.; Poplawski, Joseph V.

2015-01-01

Rolling-element bearings operated at high speed or high vibration may require a tight interference fit between the bore of the bearing and shaft to prevent rotation of the bearing bore around the shaft and fretting damage at the interfaces. Previous work showed that the hoop stresses resulting from tight interference fits can reduce bearing lives by as much as 65 percent. Where tight interference fits are required, case-carburized steel such as AISI 9310 or M50 NiL is often used because the compressive residual stresses inhibit subsurface crack formation and the ductile core inhibits inner-ring fracture. The presence of compressive residual stress and its combination with hoop stress also modifies the Hertz stress-life relation. This paper analyzes the beneficial effect of residual stresses on rolling-element bearing fatigue life in the presence of high hoop stresses for three bearing steels. These additional stresses were superimposed on Hertzian principal stresses to calculate the inner-race maximum shearing stress and the resulting fatigue life of the bearing. The load-life exponent p and Hertz stress-life exponent n increase in the presence of compressive residual stress, which yields increased life, particularly at lower stress levels. The Zaretsky life equation is described and is shown to predict longer bearing lives and greater load- and stress-life exponents, which better predicts observed life of bearings made from vacuum-processed steel.

Best Practices for Fatigue Risk Management in Non-Traditional Shiftwork

NASA Technical Reports Server (NTRS)

Flynn-Evans, Erin E.

2016-01-01

Fatigue risk management programs provide effective tools to mitigate fatigue among shift workers. Although such programs are effective for typical shiftwork scenarios, where individuals of equal skill level can be divided into shifts to cover 24 hour operations, traditional programs are not sufficient for managing sleep loss among individuals with unique skill sets, in occupations where non-traditional schedules are required. Such operations are prevalent at NASA and in other high stress occupations, including among airline pilots, military personnel, and expeditioners. These types of operations require fatigue risk management programs tailored to the specific requirements of the mission. Without appropriately tailored fatigue risk management, such operations can lead to an elevated risk of operational failure, disintegration of teamwork, and increased risk of accidents and incidents. In order to design schedules for such operations, schedule planners must evaluate the impact of a given operation on circadian misalignment, acute sleep loss, chronic sleep loss and sleep inertia. In addition, individual-level factors such as morningness-eveningness preference and sleep disorders should be considered. After the impact of each of these factors has been identified, scheduling teams can design schedules that meet operational requirements, while also minimizing fatigue.

49 CFR 192.233 - Miter joints.

Code of Federal Regulations, 2010 CFR

2010-10-01

.... (a) A miter joint on steel pipe to be operated at a pressure that produces a hoop stress of 30... operated at a pressure that produces a hoop stress of less than 30 percent, but more than 10 percent, of... steel pipe to be operated at a pressure that produces a hoop stress of 10 percent or less of SMYS may...

49 CFR 192.233 - Miter joints.

Code of Federal Regulations, 2012 CFR

2012-10-01

.... (a) A miter joint on steel pipe to be operated at a pressure that produces a hoop stress of 30... operated at a pressure that produces a hoop stress of less than 30 percent, but more than 10 percent, of... steel pipe to be operated at a pressure that produces a hoop stress of 10 percent or less of SMYS may...

49 CFR 192.233 - Miter joints.

Code of Federal Regulations, 2011 CFR

2011-10-01

.... (a) A miter joint on steel pipe to be operated at a pressure that produces a hoop stress of 30... operated at a pressure that produces a hoop stress of less than 30 percent, but more than 10 percent, of... steel pipe to be operated at a pressure that produces a hoop stress of 10 percent or less of SMYS may...

Chronic Pain Under Missile Attacks: Role of Pain Catastrophizing, Media, and Stress-Related Exposure.

PubMed

Noyman-Veksler, Gal; Shalev, Hadar; Brill, Silviu; Rudich, Zvia; Shahar, Golan

2017-10-09

We examined the effects of exposure to missile attacks on patients' pain and depressive symptoms, moderated by pain-related catastrophizing. One-hundred Israeli chronic pain patients were assessed both prior and subsequent to military operation "Protective Edge," during which thousands of missiles landed on populated areas across the country. Baseline assessment included pain, depression, and catastrophizing, and postwar assessment tapped exposure to missiles, pain, and depression. Media exposure predicted an increase in sensory pain under high levels of catastrophizing (1 SD above the mean; unstandardized simple slope = 0.57, p = .01), and depression in the entire sample (b = 0.61, p = .01). Perceived stress related to the missiles exhibited an expected effect, predicting an increase in depressive symptoms (b = 1.45, p = .03). Unexpectedly, perceived stress predicted a decrease in sensory pain under high levels of catastrophizing (unstandardized simple slope = -0.49, p = .02). Media exposure to acute stress may render chronic pain patients more vulnerable to experiencing pain and depressive symptoms, depending on their use of pain-based catastrophizing. High catastrophizers may attend more to outside threats, amplifying the sensory and affective aspects of pain they experience. Perceived stress also plays a significant role in eliciting depressive symptoms in this population. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Fluid mechanics of spinner-flask bioreactors

NASA Astrophysics Data System (ADS)

Sucosky, Philippe; Neitzel, G. Paul

2000-11-01

The dynamic environment within bioreactors used for in vitro tissue growth has been observed to affect the development of mammalian cells. Many studies have shown that moderate mechanical stress enhances growth of some tissues whereas high shear levels and turbulence seem to damage cells. In order to optimize the design and the operating conditions of bioreactors, it is important to understand the fluid-dynamic characteristics and to control the stress levels within these devices. The present research focuses on the characterization of the flow field within a spinner-flask bioreactor. The dynamic properties of the flow are investigated experimentally using particle-image velocimetry with a refractive-index-matched model. Phase-locked ensemble-averaging is employed to provide some information on the turbulence characteristics of the model culture medium in the vicinity of a model tissue construct.

Functional analysis of the pepper protein phosphatase, CaAIPP1, and its interacting partner CaAIRF1: Modulation of ABA signalling and the drought stress response.

PubMed

Baek, Woonhee; Lim, Chae Woo; Lee, Sung Chul

2017-10-01

Plant adaptive responses to abiotic stress are coordinated by restriction of plant growth and development. The plant hormone abscisic acid (ABA) is the key regulator of the response to abiotic stress, and its sensitivity determines abiotic stress tolerance levels. We previously showed that the E3 ubiquitin ligase CaAIRF1 functions as a positive regulator of ABA and drought stress via modulation of transcription and stability of the type 2C protein phosphatase CaADIP1. Here, we report the identification and functional analysis of a novel-type 2C phosphatase, CaAIPP1 (Capsicum annuum CaAIRF1 Interacting Protein Phosphatase 1). CaAIPP1 interacted with and was ubiquitinated by CaAIRF1. CaAIPP1 gene expression in pepper leaves was induced by ABA and drought. CaAIPP1 degradation was faster in crude protein extracts from ABA-treated pepper plants than in those from control plants. CaAIPP1-overexpressing plants displayed an ABA-hyposensitive phenotype during seed germination and seedling growth. Moreover, these plants exhibited a drought-sensitive phenotype characterized by high levels of transpirational water loss via decreased stomatal closure and reduced leaf temperatures. Our data indicate that CaAIPP1 is a negative regulator of the drought stress response via ABA-mediated signalling. Our findings provide a valuable insight into the plant defence mechanism that operates during drought stress. © 2017 John Wiley & Sons Ltd.

Cultural, Transcriptomic, and Proteomic Analyses of Water-Stressed Cells of Actinobacterial Strains Isolated from Compost: Ecological Implications in the Fed-Batch Composting Process.

PubMed

Narihiro, Takashi; Kanosue, Yuji; Hiraishi, Akira

2016-06-25

This study was undertaken to examine the effects of water activity (aw) on the viability of actinobacterial isolates from a fed-batch composting (FBC) process by comparing culturability and stainability with 5-cyano-2,3-ditoryl tetrazolium chloride (CTC). The FBC reactor as the source of these bacteria was operated with the daily loading of household biowaste for 70 d. During this period of composting, aw in the reactor decreased linearly with time and reached approximately 0.95 at the end of operation. The plate counts of aerobic chemoorganotrophic bacteria were 3.2-fold higher than CTC-positive (CTC+) counts on average at the fully acclimated stage (after 7 weeks of operation), in which Actinobacteria predominated, as shown by lipoquinone profiling and cultivation methods. When the actinobacterial isolates from the FBC process were grown under aw stress, no significant differences were observed in culturability among the cultures, whereas CTC stainability decreased with reductions in aw levels. A cDNA microarray-based transcriptomic analysis of a representative isolate showed that many of the genes involved in cellular metabolism and genetic information processing were down-regulated by aw stress. This result was fully supported by a proteomic analysis. The results of the present study suggest that, in low aw mature compost, the metabolic activity of the community with Actinobacteria predominating is temporarily reduced to a level that hardly reacts with CTC; however, these bacteria are easily recoverable by exposure to a high aw culture medium. This may be a plausible reason why acclimated FBC reactors in which Actinobacteria predominate yields higher plate counts than CTC+ counts.

49 CFR 192.507 - Test requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at...

Code of Federal Regulations, 2010 CFR

2010-10-01

... hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage. 192.507 Section 192... requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i... be operated at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage...

49 CFR 192.507 - Test requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at...

Code of Federal Regulations, 2012 CFR

2012-10-01

... hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage. 192.507 Section 192... requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i... be operated at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage...

49 CFR 192.507 - Test requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at...

Code of Federal Regulations, 2013 CFR

2013-10-01

... hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage. 192.507 Section 192... requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i... be operated at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage...

49 CFR 192.507 - Test requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at...

Code of Federal Regulations, 2014 CFR

2014-10-01

... hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage. 192.507 Section 192... requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i... be operated at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage...

49 CFR 192.507 - Test requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at...

Code of Federal Regulations, 2011 CFR

2011-10-01

... hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage. 192.507 Section 192... requirements for pipelines to operate at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i... be operated at a hoop stress less than 30 percent of SMYS and at or above 100 p.s.i. (689 kPa) gage...

The Determinants of Parenting: What Variables Do We Need To Look At?

ERIC Educational Resources Information Center

Abidin, Richard R.

One recently developed parenting research model hypothesizes that parenting behavior and child adjustment are influenced by a number of divergent variables that operate through the component of the parent's personality that is related to the parenting role. In this model, the level of stress experienced by each parent results from a series of…

Physiological responses to treadmill exercise and ambient temperature in normal and malignant hyperthermia susceptible pigs.

PubMed Central

D'Allaire, S; DeRoth, L

1986-01-01

Ten susceptible and ten resistant pigs to malignant hyperthermia were used to observe the effects of exercise and ambient temperature on selected physiological parameters. Pigs were submitted to a ten minute exercise on a treadmill operating at a speed of 1.8 km/h and inclined to 11 degrees. Exercise in the first group was at an ambient temperature of 14 degrees C, and in the second at 29 degrees C. The right carotid artery was previously cannulated for blood pressure measurements and for repeated blood sampling during exercise. Arterial pressure, heart rate, rectal and cutaneous temperatures were recorded. Levels of cortisol, creatine kinase and its isoenzymes were measured. At 14 degrees C, exercise caused some physiological adjustments in susceptible animals; heart rate, skin temperature and cortisol levels increased (P less than 0.05). In resistant pigs, only the heart rate was elevated significantly following exertional stress at 14 degrees C. Exercise at 29 degrees C produced severe stress and marked physiological changes: heart rate, rectal and skin temperatures and cortisol levels increased significantly in both susceptible and resistant swine. At 29 degrees C, susceptible pigs also had higher levels of serum cortisol, total creatine kinase and MM isoenzyme (P less than 0.05) compared to resistant pigs. The results indicate that, following exertional or thermal stress, susceptible pigs undergo more extensive physiological changes than do resistant pigs. Similar levels of stress prior to slaughter may trigger physiological changes which in the susceptible pigs would likely result in pale, soft exudative myopathy. PMID:3742362

Long-term relationships between perceived social support and posttraumatic stress after the 2011 Oslo bombing: A three-year longitudinal study.

PubMed

Birkeland, Marianne Skogbrott; Knatten, Charlotte Kristensen; Hansen, Marianne Bang; Hem, Camilla; Heir, Trond

2016-09-15

After traumatic events, social support and posttraumatic stress are interrelated, but little is known about the underlying dynamics behind this association. Levels of social support and posttraumatic stress may change and affect each other over time, but there are also stable time-invariant individual differences in both constructs. The present study aimed to determine the amount of variance explained by stable individual differences in levels of social support and posttraumatic stress across three years, and to determine whether and to what extent social support and posttraumatic stress may affect one another when these stable individual differences are controlled for. We used data from ministerial employees present in the Governmental district during the 2011 Oslo bombing attack (N=255). Data was collected ten months, two years, and three years after the terror attack. Using a random intercept cross lagged panel model (RI-CLPM), we tested the possible directional effects between social support and posttraumatic stress within persons when variance between persons was taken into account. The intraclass correlations of the three measures of posttraumatic stress and social support were.83 and.74, respectively. The remaining variation within persons could not be explained by change in either of these constructs. We have no information on the processes that might have occurred before 10 months after the incident. Our findings indicate that the long-term longitudinal linkage between social support and posttraumatic stress may be best explained by stable individual differences rather than causal processes operating within persons. Copyright © 2016 Elsevier B.V. All rights reserved.

Treatment of stress fracture of the olecranon in throwing athletes with internal fixation through a small incision

PubMed Central

2012-01-01

The present study is a report of retrospective case series of stress fracture of the olecranon. Six patients presented posterior elbow pain in throwing in baseball and softball, but fracture was not diagnosed in radiographs. We detected stress fracture of the olecranon using computed tomographic (CT) scan and treated the patient with internal fixation with a headless cannulated double threaded screw through a small skin incision. All patients returned to competitive level without elbow complaints after the operation. When throwing athletes present with unusual posterior elbow pain and no significant findings on radiographs, a CT scan examination should be performed. We recommend surgical treatment of internal fixation with a screw through a small skin incision, as a good option for stress fracture of the olecranon in order to allow early return to sports activity in competitive athletes. PMID:23241173

Measurement and Modeling of Job Stress of Electric Overhead Traveling Crane Operators

PubMed Central

Krishna, Obilisetty B.; Maiti, Jhareswar; Ray, Pradip K.; Samanta, Biswajit; Mandal, Saptarshi; Sarkar, Sobhan

2015-01-01

Background In this study, the measurement of job stress of electric overhead traveling crane operators and quantification of the effects of operator and workplace characteristics on job stress were assessed. Methods Job stress was measured on five subscales: employee empowerment, role overload, role ambiguity, rule violation, and job hazard. The characteristics of the operators that were studied were age, experience, body weight, and body height. The workplace characteristics considered were hours of exposure, cabin type, cabin feature, and crane height. The proposed methodology included administration of a questionnaire survey to 76 electric overhead traveling crane operators followed by analysis using analysis of variance and a classification and regression tree. Results The key findings were: (1) the five subscales can be used to measure job stress; (2) employee empowerment was the most significant factor followed by the role overload; (3) workplace characteristics contributed more towards job stress than operator's characteristics; and (4) of the workplace characteristics, crane height was the major contributor. Conclusion The issues related to crane height and cabin feature can be fixed by providing engineering or foolproof solutions than relying on interventions related to the demographic factors. PMID:26929839

The exponential rise of induced seismicity with increasing stress levels in the Groningen gas field and its implications for controlling seismic risk

NASA Astrophysics Data System (ADS)

Bourne, S. J.; Oates, S. J.; van Elk, J.

2018-06-01

Induced seismicity typically arises from the progressive activation of recently inactive geological faults by anthropogenic activity. Faults are mechanically and geometrically heterogeneous, so their extremes of stress and strength govern the initial evolution of induced seismicity. We derive a statistical model of Coulomb stress failures and associated aftershocks within the tail of the distribution of fault stress and strength variations to show initial induced seismicity rates will increase as an exponential function of induced stress. Our model provides operational forecasts consistent with the observed space-time-magnitude distribution of earthquakes induced by gas production from the Groningen field in the Netherlands. These probabilistic forecasts also match the observed changes in seismicity following a significant and sustained decrease in gas production rates designed to reduce seismic hazard and risk. This forecast capability allows reliable assessment of alternative control options to better inform future induced seismic risk management decisions.

Modeling the Effects of Stress: An Approach to Training

NASA Technical Reports Server (NTRS)

Cuper, Taryn

2010-01-01

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

Observations of instability, hysteresis, and oscillation in low-Reynolds-number flow past polymer gels.

PubMed

Eggert, Matthew D; Kumar, Satish

2004-10-01

We perform a set of experiments to study the nonlinear nature of an instability that arises in low-Reynolds-number flow past polymer gels. A layer of a viscous liquid is placed on a polydimethylsiloxane (PDMS) gel in a parallel-plate rheometer which is operated in stress-controlled mode. As the shear stress on the top plate increases, the apparent viscosity stays relatively constant until a transition stress where it sharply increases. If the stress is held at a level slightly above the transition stress, the apparent viscosity oscillates with time. If the stress is increased to a value above the transition stress and then decreased back to zero, the apparent viscosity shows hysteretic behavior. If the stress is instead decreased to a constant value and held there, the apparent viscosity is different from its pretransition value and exhibits sustained oscillations. This can happen even if the stress is held at values below the transition stress. Our observations suggest that the instability studied here is subcritical and leads to a flow that is oscillatory and far from viscometric. The phenomena reported here may be useful in applications such as microfluidics, membrane separations, and polymer processing. They may also provide insight into the rheological behavior of complex fluids that undergo flow-induced gelation.

TMBIM3/GRINA is a novel unfolded protein response (UPR) target gene that controls apoptosis through the modulation of ER calcium homeostasis

PubMed Central

Rojas-Rivera, D; Armisén, R; Colombo, A; Martínez, G; Eguiguren, A L; Díaz, A; Kiviluoto, S; Rodríguez, D; Patron, M; Rizzuto, R; Bultynck, G; Concha, M L; Sierralta, J; Stutzin, A; Hetz, C

2012-01-01

Transmembrane BAX inhibitor motif-containing (TMBIM)-6, also known as BAX-inhibitor 1 (BI-1), is an anti-apoptotic protein that belongs to a putative family of highly conserved and poorly characterized genes. Here we report the function of TMBIM3/GRINA in the control of cell death by endoplasmic reticulum (ER) stress. Tmbim3 mRNA levels are strongly upregulated in cellular and animal models of ER stress, controlled by the PERK signaling branch of the unfolded protein response. TMBIM3/GRINA synergies with TMBIM6/BI-1 in the modulation of ER calcium homeostasis and apoptosis, associated with physical interactions with inositol trisphosphate receptors. Loss-of-function studies in D. melanogaster demonstrated that TMBIM3/GRINA and TMBIM6/BI-1 have synergistic activities against ER stress in vivo. Similarly, manipulation of TMBIM3/GRINA levels in zebrafish embryos revealed an essential role in the control of apoptosis during neuronal development and in experimental models of ER stress. These findings suggest the existence of a conserved group of functionally related cell death regulators across species beyond the BCL-2 family of proteins operating at the ER membrane. PMID:22240901

TMBIM3/GRINA is a novel unfolded protein response (UPR) target gene that controls apoptosis through the modulation of ER calcium homeostasis.

PubMed

Rojas-Rivera, D; Armisén, R; Colombo, A; Martínez, G; Eguiguren, A L; Díaz, A; Kiviluoto, S; Rodríguez, D; Patron, M; Rizzuto, R; Bultynck, G; Concha, M L; Sierralta, J; Stutzin, A; Hetz, C

2012-06-01

Transmembrane BAX inhibitor motif-containing (TMBIM)-6, also known as BAX-inhibitor 1 (BI-1), is an anti-apoptotic protein that belongs to a putative family of highly conserved and poorly characterized genes. Here we report the function of TMBIM3/GRINA in the control of cell death by endoplasmic reticulum (ER) stress. Tmbim3 mRNA levels are strongly upregulated in cellular and animal models of ER stress, controlled by the PERK signaling branch of the unfolded protein response. TMBIM3/GRINA synergies with TMBIM6/BI-1 in the modulation of ER calcium homeostasis and apoptosis, associated with physical interactions with inositol trisphosphate receptors. Loss-of-function studies in D. melanogaster demonstrated that TMBIM3/GRINA and TMBIM6/BI-1 have synergistic activities against ER stress in vivo. Similarly, manipulation of TMBIM3/GRINA levels in zebrafish embryos revealed an essential role in the control of apoptosis during neuronal development and in experimental models of ER stress. These findings suggest the existence of a conserved group of functionally related cell death regulators across species beyond the BCL-2 family of proteins operating at the ER membrane.

[24-hour work: the interaction of stress and changes in the sleep-wake cycle in the police force].

PubMed

Garbarino, Sergio

2014-01-01

Disruption in police officers. In recent years there has been a widespread growth in services, available regardless of time or day organization (24/7 service) and a diffuse increase in their use, both in work and private lives, generally ignoring the importance of a regular sleep organization. Police officers - often need to work extended shifts and long hours under highly stressful conditions, which results in reduced levels of safety and operational effectiveness. In numerous studies, perceived stress has been found to correlate with both subjective and objective disturbances in sleep. Consequently, excessive daytime sleepiness is one of the most frequent health and safety hazards that police officers have to deal with. Sleep deprivation affects performance outcomes through a wide range of cognitive domains. Sleepiness and fatigue, caused by sleep loss, extended work and wakefulness, circadian misalignment and sleep disorders are major causes of workplace human errors, incidents, and accidents. Therefore, prevention of sleep loss, high levels of stress and fatigue is a key factor to consider when assessing emergency intervention. In order to combat fatigue and sleepiness, a 30-90 minutes nap before night shift could be a viable option.

Effect of peripheral irregularities in the temperature field during turbine startups with flange heating along the reduction on the durability of turbine casings

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

Beryland, V.I.; Glyadya, A.A.; Pozhidaev, A.V.

1982-07-01

One method for improving the operating flexibility of 150, 200, and 300 MW steam turbines is heating the flanges of the horizontal casing point during startup, both when cold and before cooling down. A design analysis was conducted of the comparative effectiveness of various heating systems from the standpoint of minimizing both temperature differences across the flange width, as well as the level of related thermal stresses. The effects of flange heating during the entire operating period are discussed.

Brain aluminium accumulation and oxidative stress in the presence of calcium silicate dental cements.

PubMed

Demirkaya, K; Demirdöğen, B Can; Torun, Z Öncel; Erdem, O; Çırak, E; Tunca, Y M

2017-10-01

Mineral trioxide aggregate (MTA) is a calcium silicate dental cement used for various applications in dentistry. This study was undertaken to test whether the presence of three commercial brands of calcium silicate dental cements in the dental extraction socket of rats would affect the brain aluminium (Al) levels and oxidative stress parameters. Right upper incisor was extracted and polyethylene tubes filled with MTA Angelus, MTA Fillapex or Theracal LC, or left empty for the control group, were inserted into the extraction socket. Rats were killed 7, 30 or 60 days after operation. Brain tissues were obtained before killing. Al levels were measured by atomic absorption spectrometry. Thiobarbituric acid reactive substances (TBARS) levels, catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were determined using spectrophotometry. A transient peak was observed in brain Al level of MTA Angelus group on day 7, while MTA Fillapex and Theracal LC groups reached highest brain Al level on day 60. Brain TBARS level, CAT, SOD and GPx activities transiently increased on day 7 and then returned to almost normal levels. This in vivo study for the first time indicated that initial washout may have occurred in MTA Angelus, while element leaching after the setting is complete may have taken place for MTA Fillapex and Theracal LC. Moreover, oxidative stress was induced and antioxidant enzymes were transiently upregulated. Further studies to search for oxidative neuronal damage should be done to completely understand the possible toxic effects of calcium silicate cements on the brain.

Assessment of possible failure modes and non-destructive examination of the ITER pre-compression rings

NASA Astrophysics Data System (ADS)

Knaster, J.; Evans, D.; Rajainmaki, H.

2012-06-01

The pre-compression rings (PCRs) for the International Thermonuclear Experimental Reactor (ITER) represent one of the largest and most highly stressed composite structures ever designed for long term operation at 4K. Three rings, each 5m in diameter and 337 × 288 mm in cross-section, will be installed at the top and bottom of the eighteen "D" shaped Toroidal Field (TF) coils to apply a total centripetal load of 70 MN per TF coil. The interaction of the 68 kA conductor current circulating in the coil (for a total of 9.1MA) with the required magnetic field to confine the plasma during operation will result in Lorentz forces that build in-plane and out-of-plane loads. The PCRs are essential to keep the stresses below the acceptable level for the ITER magnets structural materials.

Phenytoin as a countermeasure for motion sickness in NASA maritime operations

NASA Technical Reports Server (NTRS)

Woodard, Daniel; Knox, Glenn; Myers, K. J.; Chelen, William; Ferguson, Becki

1993-01-01

Seasickness is the most prevalent form of motion sickness and is an operational problem during Space Shuttle Solid-fueled Rocket Booster (SRB) retrieval. Phenytoin has been shown to protect against motion sickness induced by Coriolis stress. We exposed SRB recovery personnel to off-vertical rotation and sea motion after phenytoin or placebo. Phenytoin blood levels of at least 9 micrograms/ml were protective against motion sickness at sea. No change in susceptibility to nitrogen narcosis was seen in divers in chamber tests at 460 KPa. Phenytoin was used during the performance of critical and hazardous tasks during training and actual SRB recovery operations. Phenytoin is an effective operational countermeasure for motion sickness for selected SRB crew members.

Relationship between psychosocial stress dimensions and salivary cortisol in military police officers 1

PubMed Central

Tavares, Juliana Petri; Lautert, Liana; Magnago, Tânia Solange Bosi de Souza; Consiglio, Angélica Rosat; Pai, Daiane Dal

2017-01-01

Abstract Objective: to analyze the relationship between psychosocial stress dimensions and salivary cortisol in military police officers. Method: cross-sectional and analytical study with 134 military police officers. The Effort-Reward Imbalance (ERI) Model scale has been used to assess psychosocial stress. Salivary cortisol was collected in three samples. The following tests were used: Student's t-test, Mann-Whitney, ANOVA, Bonferroni, Kruskal-Wallis and Dunn. Pearson and Spearman correlation methods were used, as well as multiple linear regression. Cortisol at night showed an ascending statistical association with the psychosocial reward (p=0.004) and a descending association with the effort-impairment scores (p=0.017). Being part of the Special Tactical Operations Group (GATE) and the diastolic blood pressure explained 13.5% of the variation in cortisol levels on waking up. The sectors GATE, Special Patrol of the Elite Squad of the Military Police and Motorcyclists explained 21.9% of the variation in cortisol levels 30-minute after awakening. The variables GATE sector and Effort Dimension explained 27.7% of the variation in cortisol levels at night. Conclusion: it was evidenced that salivary cortisol variation was influenced by individual, labor and psychosocial variables. PMID:28443994

Relationship between psychosocial stress dimensions and salivary cortisol in military police officers.

PubMed

Tavares, Juliana Petri; Lautert, Liana; Magnago, Tânia Solange Bosi de Souza; Consiglio, Angélica Rosat; Pai, Daiane Dal

2017-04-20

to analyze the relationship between psychosocial stress dimensions and salivary cortisol in military police officers. cross-sectional and analytical study with 134 military police officers. The Effort-Reward Imbalance (ERI) Model scale has been used to assess psychosocial stress. Salivary cortisol was collected in three samples. The following tests were used: Student's t-test, Mann-Whitney, ANOVA, Bonferroni, Kruskal-Wallis and Dunn. Pearson and Spearman correlation methods were used, as well as multiple linear regression. Cortisol at night showed an ascending statistical association with the psychosocial reward (p=0.004) and a descending association with the effort-impairment scores (p=0.017). Being part of the Special Tactical Operations Group (GATE) and the diastolic blood pressure explained 13.5% of the variation in cortisol levels on waking up. The sectors GATE, Special Patrol of the Elite Squad of the Military Police and Motorcyclists explained 21.9% of the variation in cortisol levels 30-minute after awakening. The variables GATE sector and Effort Dimension explained 27.7% of the variation in cortisol levels at night. it was evidenced that salivary cortisol variation was influenced by individual, labor and psychosocial variables.

Factors Influencing the Fatigue Strength of Materials

NASA Technical Reports Server (NTRS)

Bollenrath, F

1941-01-01

A number of factors are considered which influence the static and fatigue strength of materials under practical operating conditions as contrasted with the relations obtaining under conditions of the usual testing procedure. Such factors are interruptions in operation, periodically fluctuating stress limits and mean stresses with periodic succession of several groups and stress states, statistical changes and succession of stress limits and mean stresses, frictional corrosion at junctures, and notch effects.

Stress training improves performance during a stressful flight.

PubMed

McClernon, Christopher K; McCauley, Michael E; O'Connor, Paul E; Warm, Joel S

2011-06-01

This study investigated whether stress training introduced during the acquisition of simulator-based flight skills enhances pilot performance during subsequent stressful flight operations in an actual aircraft. Despite knowledge that preconditions to aircraft accidents can be strongly influenced by pilot stress, little is known about the effectiveness of stress training and how it transfers to operational flight settings. For this study, 30 participants with no flying experience were assigned at random to a stress-trained treatment group or a control group. Stress training consisted of systematic pairing of skill acquisition in a flight simulator with stress coping mechanisms in the presence of a cold pressor. Control participants received identical flight skill acquisition training but without stress training. Participants then performed a stressful flying task in a Piper Archer aircraft. Stress-trained research participants flew the aircraft more smoothly, as recorded by aircraft telemetry data, and generally better, as recorded by flight instructor evaluations, than did control participants. Introducing stress coping mechanisms during flight training improved performance in a stressful flying task. The results of this study indicate that stress training during the acquisition of flight skills may serve to enhance pilot performance in stressful operational flight and, therefore, might mitigate the contribution of pilot stress to aircraft mishaps.

Subsyndromal posttraumatic stress disorder symptomatology in primary care military veterans: treatment implications.

PubMed

Kornfield, Sara L; Klaus, Johanna; McKay, Caroline; Helstrom, Amy; Oslin, David

2012-11-01

Subsyndromal posttraumatic stress disorder (PTSD) is highly prevalent in Veterans Affairs Medical Centers' primary-care clinics and is associated with significant impairment. We used a cross-sectional design to examine PTSD symptoms and depressive disorders endorsed by two cohorts of Veterans meeting less than full PTSD criteria who presented to primary care at the Philadelphia VA Medical Center (i.e., those from Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) and non-OEF/OIF/OND Veterans). The Philadelphia VA Behavioral Health Lab (BHL) assessed 141 Veterans who screened positive for subsyndromal PTSD. Avoidance was endorsed significantly less often than arousal in the total group. When the groups were split by cohort era, higher levels of avoidance and lower levels of arousal were reported in the non-OEF/OIF/OND group than the OEF/OIF/OND group. Comorbid depression was present in 43.9% of the total group with no significant differences between groups. Exposure-based treatments for PTSD offered in specialty mental health clinics target avoidance symptoms. Because the endorsement of avoidance symptoms was low in both of the cohorts that were studied this may not be the most effective treatment target for Veterans with subsyndromal PTSD receiving treatment in primary care settings. For these Veterans, treatments that target reexperiencing and arousal symptoms and/or comorbid depression may be more effective.

Pathogens and Disease Play Havoc on the Host Epiproteome-The "First Line of Response" Role for Proteomic Changes Influenced by Disorder.

PubMed

Rikkerink, Erik H A

2018-03-08

Organisms face stress from multiple sources simultaneously and require mechanisms to respond to these scenarios if they are to survive in the long term. This overview focuses on a series of key points that illustrate how disorder and post-translational changes can combine to play a critical role in orchestrating the response of organisms to the stress of a changing environment. Increasingly, protein complexes are thought of as dynamic multi-component molecular machines able to adapt through compositional, conformational and/or post-translational modifications to control their largely metabolic outputs. These metabolites then feed into cellular physiological homeostasis or the production of secondary metabolites with novel anti-microbial properties. The control of adaptations to stress operates at multiple levels including the proteome and the dynamic nature of proteomic changes suggests a parallel with the equally dynamic epigenetic changes at the level of nucleic acids. Given their properties, I propose that some disordered protein platforms specifically enable organisms to sense and react rapidly as the first line of response to change. Using examples from the highly dynamic host-pathogen and host-stress response, I illustrate by example how disordered proteins are key to fulfilling the need for multiple levels of integration of response at different time scales to create robust control points.

SCC of 2304 Duplex Stainless Steel—Microstructure, Residual Stress and Surface Grinding Effects

PubMed Central

Zhou, Nian; Peng, Ru Lin; Schönning, Mikael; Pettersson, Rachel

2017-01-01

The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental. PMID:28772582

SCC of 2304 Duplex Stainless Steel-Microstructure, Residual Stress and Surface Grinding Effects.

PubMed

Zhou, Nian; Peng, Ru Lin; Schönning, Mikael; Pettersson, Rachel

2017-02-23

The influence of surface grinding and microstructure on chloride induced stress corrosion cracking (SCC) behavior of 2304 duplex stainless steel has been investigated. Grinding operations were performed both parallel and perpendicular to the rolling direction of the material. SCC tests were conducted in boiling magnesium chloride according to ASTM G36; specimens were exposed both without external loading and with varied levels of four-point bend loading. Residual stresses were measured on selected specimens before and after exposure using the X-ray diffraction technique. In addition, in-situ surface stress measurements subjected to four-point bend loading were performed to evaluate the deviation between the actual applied loading and the calculated values according to ASTM G39. Micro-cracks, initiated by grinding induced surface tensile residual stresses, were observed for all the ground specimens but not on the as-delivered surfaces. Loading transverse to the rolling direction of the material increased the susceptibility to chloride induced SCC. Grinding induced tensile residual stresses and micro-notches in the as-ground surface topography were also detrimental.

Sleep deficit and stress hormones in helicopter pilots on 7-day duty for emergency medical services.

PubMed

Samel, Alexander; Vejvoda, Martin; Maass, Hartmut

2004-11-01

Helicopter-based emergency medical services in Germany operate from sunrise to sunset, requiring up to 15.5 h of continuous duty during the summer months for pilots, who work for seven consecutive days. Because of concerns regarding the safety of this procedure with respect to pilot fatigue and stress, the German Ministry of Transport asked our laboratory to investigate the risks involved. There were 13 pilots (mean age 38 yr) who were studied in the summer months for 2 d before, 7 d during, and 2 d after their duty cycle. Measured variables included sleep duration and quality, subjective fatigue, and heart rate, as well as 24-h excretion levels of stress hormones. During actual helicopter operations, maximum heart rates did not exceed 120 bpm. Over the 7-d duty period, mean sleep duration decreased from 7.8 h to 6 h or less, resulting in a cumulative sleep loss of about 15 h. Mean levels of excreted adrenalin, noradrenalin, and cortisol increased significantly by 50 to 80%; cortisol and noradrenalin excretion also remained elevated for the two post-duty days. Although the actual flights did not cause critical physiological responses, the acute and accumulated sleep deficit led to incomplete recuperation between duty hours and induced elevated stress indicators. It was, therefore, recommended that the duty cycle be amended as follows: 1.) enforce a 10-h rest period and at least an 8-h sleep opportunity per day; 2.) modify the duty period to allow no more than 3 consecutive rest periods of reduced sleep opportunities (8.5 h); and 3.) follow duty with several days that offer unrestricted sleep opportunities.

Reshaping of large aeronautical structural parts: A simplified simulation approach

NASA Astrophysics Data System (ADS)

Mena, Ramiro; Aguado, José V.; Guinard, Stéphane; Huerta, Antonio

2018-05-01

Large aeronautical structural parts present important distortions after machining. This problem is caused by the presence of residual stresses, which are developed during previous manufacturing steps (quenching). Before being put into service, the nominal geometry is restored by means of mechanical methods. This operation is called reshaping and exclusively depends on the skills of a well-trained and experienced operator. Moreover, this procedure is time consuming and nowadays, it is only based on a trial and error approach. Therefore, there is a need at industrial level to solve this problem with the support of numerical simulation tools. By using a simplification hypothesis, it was found that the springback phenomenon behaves linearly and it allows developing a strategy to implement reshaping at an industrial level.

A noise-reduction program in a pediatric operation theatre is associated with surgeon's benefits and a reduced rate of complications: a prospective controlled clinical trial.

PubMed

Engelmann, Carsten R; Neis, Jan Philipp; Kirschbaum, Clemens; Grote, Gudela; Ure, Benno M

2014-05-01

We assessed the impact of a noise-reduction program in a pediatric operating theatre. Adverse effects from noise pollution in theatres have been demonstrated. In 156 operations spatially resolved, sound levels were measured before and after a noise-reduction program on the basis of education, rules, and technical devices (Sound Ear). Surgical complications were recorded. The surgeon's biometric (saliva cortisol, electrodermal activity) and behavioral stress responses (questionnaires) were measured and correlated with mission protocols and individual noise sensitivity. Median noise levels in the control group versus the interventional group were reduced by -3 ± 3 dB(A) (63 vs 59 dB(A), P < 0.001) with a grossly decreased number of peaks greater than 70 dB(A) (Δn = -61/hour, P < 0.01). The intervention significantly reduced non-operation-related noise. The incidence of postoperative complications was significantly lower in patients of the intervention group (n = 10/56 vs 20/58 control; P < 0.05). "Responders," surgeons with an above-average noise sensitivity (correlation r = -0.6 for the work subscale of the NoiseQ questionnaire, P < 0.05), experienced improved intrateam communication, a decrease in disturbing conversations and sudden noise peaks (P < 0.05). Biometrically, the intervention decreased both the surgeon's pre- to postoperative rise in cortisol by approximately 20% and the surgeon's electrodermal potentials of greater than 15 μS, indicating severe stress by 60% (P > 0.05). Spontaneous noise during pediatric operations attains the magnitude of a lawn mower and peaks resemble a passing truck. The sound intensity could be reduced by 50% by specific measures. This reduction was associated with a significantly lowered number of postoperative complications. The surgeon's benefits are idiosyncratic with "responders" experiencing marked improvements.

Measurements on the Magdalen Islands VAWT and future projects

NASA Astrophysics Data System (ADS)

Gallagher, N. C.; Rangi, R. S.

The rotor of a 224 kW vertical axis wind turbine (VAWT) is discussed. The rebuilt rotor of the 224 kW Magdalen Islands VAWT was installed in Sept. 1979 and is operating at its design speed (36.6 rpm). Agreement between measured and theoretical performance is generally good except that maximum power may exceed theoretical predictions. Measurements of drive train losses, torque and power ripple, and rotor stresses are discussed. Although peak-to-peak cyclic stress levels are low in relation to fatigue life limits, spectral analysis of stress data indicates that the 3-per-rev component is amplified by near-resonance with the first butterfly blade mode. This resonance was subsequently de-coupled by a damped connection between the blade struts and the central column.

The running athlete: stress fractures, osteitis pubis, and snapping hips.

PubMed

Henning, P Troy

2014-03-01

Pelvic stress fractures, osteitis pubis, and snapping hip syndrome account for a portion of the overuse injuries that can occur in the running athlete. PUBMED SEARCHES WERE PERFORMED FOR EACH ENTITY USING THE FOLLOWING KEYWORDS: snapping hip syndrome, coxa sultans, pelvic stress fracture, and osteitis pubis from 2008 to 2013. Topic reviews, case reports, case series, and randomized trials were included for review. Clinical review. Level 4. Collectively, 188 articles were identified. Of these, 58 were included in this review. Based on the available evidence, the majority of these overuse injuries can be managed non-operatively. Primary treatment should include removal from offending activity, normalizing regional muscle strength/length imbalances and nutritional deficiencies, and mitigating training errors through proper education of the athlete and training staff. C.

The CMEMS L3 scatterometer wind product

NASA Astrophysics Data System (ADS)

de Kloe, Jos; Stoffelen, Ad; Verhoef, Anton

2017-04-01

Within the Copernicus Marine Environment Monitoring Service KNMI produces several ocean surface Level 3 wind products. These are daily updated global maps on a regular grid of the available scatterometer wind observations and derived properties, and produced from our EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF) operational near-real time (NRT) Level 2 swath-based wind products by linear interpolation. Currently available products are the ASCAT on Metop A/B stress equivalent wind vectors, accompanied by ECMWF NWP reference stress equivalent winds from the operational ECMWF NWP model. For each ASCAT scatterometer we provide products on 2 different resolutions, 0.25 and 0.125 degrees. In addition we provide wind stress vectors, and derivative fields (curl and divergence) for stress equivalent wind and wind stress, both for the observations and for the NWP reference winds. New NRT scatterometer products will be made available when additional scatterometer instruments become available, and NRT access to the data can be arranged. We hope OSCAT on the Indian ScatSat-1 satellite will be the the next NRT product to be added. In addition multi-year reprocessing datasets have been made available for ASCAT on Metop-A (1-Jan-2007 up to 31-Mar-2014) and Seawinds on QuikScat (19-Jul-1999 up to 21-Nov-2009). For ASCAT 0.25 and 0.125 degree resolution products are provided, and for QuikScat 0.50 and 0.25 degree resolution products are provided, These products are based on reprocessing the L2 scatterometer products with the latest processing software version, and include reference winds from the ECMWF ERA-Interim model. Additional reprocessing datasets will be added when reprocessed L2 datasets become available. This will hopefully include the ERS-1 and ERS-2 scatterometer datasets (1992-2001), which will extend the available date range back to 1992. These products are available for download through the CMEMS portal website: http://marine.copernicus.eu/

Family stressors and postdeployment mental health in single versus partnered parents deployed in support of the wars in Afghanistan and Iraq.

PubMed

Vaughn-Coaxum, Rachel; Smith, Brian N; Iverson, Katherine M; Vogt, Dawne

2015-08-01

Little is known about the family-related stress and postdeployment adjustment of single versus partnered parents deployed in support of the wars in Iraq and Afghanistan. This study examined exposure to family-related stressors during and after deployment, as well as postdeployment psychological symptoms in a national sample of 318 single (n = 74) and partnered (n = 244) parent veterans of Operation Enduring Freedom and Operation Iraqi Freedom. Results demonstrated that single parents experienced higher levels of concern about life and family disruptions during deployment, lower levels of social support during and after deployment, and poorer postdeployment family functioning than partnered parents. Single parents also reported higher posttraumatic stress symptom severity, but not depression or anxiety symptom severity, compared with partnered parents. Family-related stressors demonstrated different associations with mental health for single and partnered parents, suggesting that some stressor-symptom relations may be more salient for single parents, and others may be more salient for partnered parents. Findings suggest that the deployment and postdeployment experiences of parents differ based on their partnered status, which has implications for the design and provision of services to single and partnered parents. (c) 2015 APA, all rights reserved).

Protective effects of Tribulus terrestris L extract against acute kidney injury induced by reperfusion injury in rats.

PubMed

Najafi, Houshang; Firouzifar, Mohammad Reza; Shafaat, Omid; Changizi Ashtiyani, Saeed; Hosseini, Nasser

2014-07-01

This study aimed to investigate the protective effect of aerial parts of the Tribulus terrestris L extract on acute kidney injury (AKI) induced by ischemia for 30 minutes and reperfusion for 24 hours in rats. Ten male Sprague-Dawley rats in the AKI and 10 in the Tribulus terrestris groups received the extract solvent and extract of the plant (11 mg/kg), respectively, for 13 days (oral administration). On day 14, ischemia for 30 minutes and reperfusion for 24 hours were induced on the rats. In the last 6 hours of the reperfusion period (24 hours), urine samples were collected in metabolic cages. At the end of this period, blood samples were also taken to determine plasma urea nitrogen, creatinine, and electrolyte concentrations. The kidney tissues were collected for measuring the level of oxidative stress and histological studies. They were compared with the sham operation group and a control group with normal diet and no operation. In the Tribulus terrestris group, the increase in plasma creatinine and urea nitrogen concentrations was significantly less following reperfusion, and their values reached the same level as that in the sham group. Creatinine clearance and urine osmolarity in the Tribulus terrestris group was higher in comparison with the AKI group, whereas sodium absolute excretion, fractional excretion of potassium, oxidative stress, and cellular damages were less. Oral administration of Tribulus terrestris extract for 2 weeks can decrease kidney functional disturbance, oxidative stress, and cellular damages following reperfusion injury in rats.

The Running Athlete

PubMed Central

Henning, P. Troy

2014-01-01

Context: Pelvic stress fractures, osteitis pubis, and snapping hip syndrome account for a portion of the overuse injuries that can occur in the running athlete. Evidence Acquisition: PubMed searches were performed for each entity using the following keywords: snapping hip syndrome, coxa sultans, pelvic stress fracture, and osteitis pubis from 2008 to 2013. Topic reviews, case reports, case series, and randomized trials were included for review. Study Design: Clinical review. Level of Evidence: Level 4. Results: Collectively, 188 articles were identified. Of these, 58 were included in this review. Conclusion: Based on the available evidence, the majority of these overuse injuries can be managed non-operatively. Primary treatment should include removal from offending activity, normalizing regional muscle strength/length imbalances and nutritional deficiencies, and mitigating training errors through proper education of the athlete and training staff. Strength of Recommendation Taxonomy: C PMID:24587861

Traumatic events, other operational stressors and physical and mental health reported by Australian Defence Force personnel following peacekeeping and war-like deployments

PubMed Central

2012-01-01

Background The association between stressful events on warlike deployments and subsequent mental health problems has been established. Less is known about the effects of stressful events on peacekeeping deployments. Methods Two cross sectional studies of the Australian Defence Force were used to contrast the prevalence of exposures reported by a group deployed on a peacekeeping operation (Bougainville, n = 1704) and those reported by a group deployed on operations which included warlike and non-warlike exposures (East Timor, n = 1333). A principal components analysis was used to identify groupings of non-traumatic exposures on deployment. Multiple regression models were used to assess the association between self-reported objective and subjective exposures, stressors on deployment and subsequent physical and mental health outcomes. Results The principal components analysis produced four groups of non-traumatic stressors which were consistent between the peacekeeping and more warlike deployments. These were labelled ‘separation’, ‘different culture’, ‘other people’ and ‘work frustration’. Higher levels of traumatic and non-traumatic exposures were reported by veterans of East Timor compared to Bougainville. Higher levels of subjective traumatic exposures were associated with increased rates of PTSD in East Timor veterans and more physical and psychological health symptoms in both deployed groups. In Bougainville and East Timor veterans some non-traumatic deployment stressors were also associated with worse health outcomes. Conclusion Strategies to best prepare, identify and treat those exposed to traumatic events and other stressors on deployment should be considered for Defence personnel deployed on both warlike and peacekeeping operations. PMID:22830494

Traumatic events, other operational stressors and physical and mental health reported by Australian Defence Force personnel following peacekeeping and war-like deployments.

PubMed

Waller, Michael; Treloar, Susan A; Sim, Malcolm R; McFarlane, Alexander C; McGuire, Annabel C L; Bleier, Jonathan; Dobson, Annette J

2012-07-26

The association between stressful events on warlike deployments and subsequent mental health problems has been established. Less is known about the effects of stressful events on peacekeeping deployments. Two cross sectional studies of the Australian Defence Force were used to contrast the prevalence of exposures reported by a group deployed on a peacekeeping operation (Bougainville, n = 1704) and those reported by a group deployed on operations which included warlike and non-warlike exposures (East Timor, n = 1333). A principal components analysis was used to identify groupings of non-traumatic exposures on deployment. Multiple regression models were used to assess the association between self-reported objective and subjective exposures, stressors on deployment and subsequent physical and mental health outcomes. The principal components analysis produced four groups of non-traumatic stressors which were consistent between the peacekeeping and more warlike deployments. These were labelled 'separation', 'different culture', 'other people' and 'work frustration'. Higher levels of traumatic and non-traumatic exposures were reported by veterans of East Timor compared to Bougainville. Higher levels of subjective traumatic exposures were associated with increased rates of PTSD in East Timor veterans and more physical and psychological health symptoms in both deployed groups. In Bougainville and East Timor veterans some non-traumatic deployment stressors were also associated with worse health outcomes. Strategies to best prepare, identify and treat those exposed to traumatic events and other stressors on deployment should be considered for Defence personnel deployed on both warlike and peacekeeping operations.

Model-based development of low-level control strategies for transient operation of solid oxide fuel cell systems

NASA Astrophysics Data System (ADS)

Sorrentino, Marco; Pianese, Cesare

The exploitation of an SOFC-system model to define and test control and energy management strategies is presented. Such a work is motivated by the increasing interest paid to SOFC technology by industries and governments due to its highly appealing potentialities in terms of energy savings, fuel flexibility, cogeneration, low-pollution and low-noise operation. The core part of the model is the SOFC stack, surrounded by a number of auxiliary devices, i.e. air compressor, regulating pressure valves, heat exchangers, pre-reformer and post-burner. Due to the slow thermal dynamics of SOFCs, a set of three lumped-capacity models describes the dynamic response of fuel cell and heat exchangers to any operation change. The dynamic model was used to develop low-level control strategies aimed at guaranteeing targeted performance while keeping stack temperature derivative within safe limits to reduce stack degradation due to thermal stresses. Control strategies for both cold-start and warmed-up operations were implemented by combining feedforward and feedback approaches. Particularly, the main cold-start control action relies on the precise regulation of methane flow towards anode and post-burner via by-pass valves; this strategy is combined with a cathode air-flow adjustment to have a tight control of both stack temperature gradient and warm-up time. Results are presented to show the potentialities of the proposed model-based approach to: (i) serve as a support to control strategies development and (ii) solve the trade-off between fast SOFC cold-start and avoidance of thermal-stress caused damages.

Perceived fitness protects against stress-based mental health impairments among police officers who report good sleep.

PubMed

Gerber, Markus; Kellmann, Micheal; Elliot, Catherine; Hartmann, Tim; Brand, Serge; Holsboer-Trachsler, Edith; Pühse, Uwe

2014-01-01

This study examined a cognitive stress-moderation model that posits that the harmful effects of chronic stress are decreased in police officers who perceive high levels of physical fitness. It also determined whether the stress-buffering effect of perceived fitness is influenced by officers' self-reported sleep. A total of 460 police officers (n=116 females, n=344 males, mean age: M=40.7; SD=9.7) rated their physical fitness and completed a battery of self-report stress, mental health, and sleep questionnaires. Three-way analyses of covariance were performed to examine whether officers' self-reported mental health status depends on the interaction between stress, perceived fitness and sleep. Highly stressed officers perceived lower mental health and fitness and were overrepresented in the group of poor sleepers. Officers with high fitness self-reports revealed increased mental health and reported good sleep. In contrast, poor sleepers scored lower on the mental health index. High stress was more closely related to low mental health among poor sleepers. Most importantly, perceived fitness revealed a stress-buffering effect, but only among officers who reported good sleep. High perceived fitness and good sleep operate as stress resilience resources among police officers. The findings suggest that multimodal programs including stress management, sleep hygiene and fitness training are essential components of workplace health promotion in the police force.

Transient Protection from Heat-Stress Induced Apoptotic Stimulation by Metastasis-Associated Protein 1 in Pachytene Spermatocytes

PubMed Central

Guo, Sheng-jie; Li, Zhen; Feng, Xiao; Ma, Li; Zhang, Jin-shan; Liu, Xin-ping; Zhang, Yuan-qiang

2011-01-01

Background Deregulated thermal factors have been frequently implicated in the pathogenesis of male infertility, but the molecular basis through which certain responses are directed remain largely unknown. We previously reported that overexpression of exogenous Metastasis-associated protein 1 (MTA1) protects spermatogenic tumor cells GC-2spd (ts) against heat-induced apoptosis. To further dissect the underlying mechanism, we addressed here the fine coordination between MTA1 and p53 in pachytene spermatocytes upon hyperthermal stimulation. Methodology/Principal Findings High level of MTA1 expression sustained for 1.5 h in primary spermatocytes after heat stress before a notable decrease was detected conversely correlated to the gradual increase of acetylation status of p53 and of p21 level. Knockdown of the endogenous MTA1 in GC-2spd (ts) elevated the acetylation of p53 by diminishing the recruitment of HDAC2 and thereafter led to a dramatic increase of apoptosis after heat treatment. Consistent with this, in vivo interference of MTA1 expression in the testes of C57BL/6 mice also urged an impairment of the differentiation of spermatocytes and a disruption of Sertoli cell function due to the elevated apoptotic rate after heat stress. Finally, attenuated expression of MTA1 of pachytene spermatocytes was observed in arrested testes (at the round spermatid level) of human varicocele patients. Conclusions These data underscore a transient protective effect of this histone modifier in primary spermatocytes against heat-stress, which may operate as a negative coregulator of p53 in maintenance of apoptotic balance during early phase after hyperthermal stress. PMID:22022494

Changes in fibroblast mechanostat set point and mechanosensitivity: an adaptive response to mechanical stress in floppy eyelid syndrome.

PubMed

Ezra, Daniel G; Ellis, James S; Beaconsfield, Michèle; Collin, Richard; Bailly, Maryse

2010-08-01

Floppy eyelid syndrome (FES) is an acquired hyperelasticity disorder affecting the upper eyelid. The tarsal plate becomes hyperelastic with a loss of intrinsic rigidity. As a result, the eyelid is subjected to cyclic mechanical stress. This condition was used as a model to investigate changes in dynamic fibroblast contractility in the context of chronic cyclic mechanical stress. Contractile efficiency was investigated in a free-floating, three-dimensional collagen matrix model. Intrinsic cellular force measurements and responses to changes in gel tension were explored using a tensioning culture force monitor (t-CFM). Gene expression differences between cell lines exhibiting differences in contractile phenotype were explored with a genome level microarray platform and RT-PCR. FES tarsal plate fibroblasts (TFs) showed an increased contractile efficiency compared with the control, and t-CFM measurements confirmed a higher intrinsic cellular force at plateau levels. Cyclic stretch/relaxation experiments determined that TFs in FES maintained a functional tensional homeostasis response but with an altered sensitivity, operating around a higher mechanostat set point. Gene expression array and RT-PCR analysis identified V-CAM1 and PPP1R3C as being upregulated in FES TFs. These changes may represent an adaptive response that allows tensional homeostasis to be maintained at the high levels of tissue stress experienced in FES. Gene expression studies point to a role for V-CAM1 and PPP1R3C in mediating changes in the dynamic range of mechanosensitivity of TFs. This work identifies FES as a useful model for the study of adaptive physiological responses to mechanical stress.

Social defeat disrupts reward learning and potentiates striatal nociceptin/orphanin FQ mRNA in rats.

PubMed

Der-Avakian, Andre; D'Souza, Manoranjan S; Potter, David N; Chartoff, Elena H; Carlezon, William A; Pizzagalli, Diego A; Markou, Athina

2017-05-01

Mood disorders can be triggered by stress and are characterized by deficits in reward processing, including disrupted reward learning (the ability to modulate behavior according to past rewards). Reward learning is regulated by the anterior cingulate cortex (ACC) and striatal circuits, both of which are implicated in the pathophysiology of mood disorders. Here, we assessed in rats the effects of a potent stressor (social defeat) on reward learning and gene expression in the ACC, ventral tegmental area (VTA), and striatum. Adult male Wistar rats were trained on an operant probabilistic reward task (PRT) and then exposed to 3 days of social defeat before assessment of reward learning. After testing, the ACC, VTA, and striatum were dissected, and expression of genes previously implicated in stress was assessed. Social defeat blunted reward learning (manifested as reduced response bias toward a more frequently rewarded stimulus) and was associated with increased nociceptin/orphanin FQ (N/OFQ) peptide mRNA levels in the striatum and decreased Fos mRNA levels in the VTA. Moreover, N/OFQ peptide and nociceptin receptor mRNA levels in the ACC, VTA and striatum were inversely related to reward learning. The behavioral findings parallel previous data in humans, suggesting that stress similarly disrupts reward learning in both species. Increased striatal N/OFQ mRNA in stressed rats characterized by impaired reward learning is consistent with accumulating evidence that antagonism of nociceptin receptors, which bind N/OFQ, has antidepressant-like effects. These results raise the possibility that nociceptin systems represent a molecular substrate through which stress produces reward learning deficits in mood disorders.

Family stress and posttraumatic stress: the impact of military operations on military health care providers.

PubMed

Gibbons, Susanne W; Barnett, Scott D; Hickling, Edward J

2012-08-01

This study uses data from the 2005 Department of Defense Survey of Health-Related Behaviors Among Military Personnel to examine relationships between family stress and posttraumatic stress symptoms across 4 subgroups of Operation Iraqi Freedom-deployed (i.e., war in Iraq) or Operation Enduring Freedom-deployed (i.e., war in Afghanistan) active-duty military service members. Results suggest the following: (a) the greatest positive correlation of family stressors with posttraumatic stress symptoms was found within the military health care officer group, and (b) these military health care officers differed in family stressors mediating posttraumatic stress with divorce and financial problems accounting for significant and unique portions of the variance. Implications for care of service members and their families are discussed. Published by Elsevier Inc.

Post-Treatment Hemodynamics of a Basilar Aneurysm and Bifurcation

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

Ortega, J; Hartman, J; Rodriguez, J

2008-01-16

Aneurysm re-growth and rupture can sometimes unexpectedly occur following treatment procedures that were initially considered to be successful at the time of treatment and post-operative angiography. In some cases, this can be attributed to surgical clip slippage or endovascular coil compaction. However, there are other cases in which the treatment devices function properly. In these instances, the subsequent complications are due to other factors, perhaps one of which is the post-treatment hemodynamic stress. To investigate whether or not a treatment procedure can subject the parent artery to harmful hemodynamic stresses, computational fluid dynamics simulations are performed on a patient-specific basilarmore » aneurysm and bifurcation before and after a virtual endovascular treatment. The simulations demonstrate that the treatment procedure produces a substantial increase in the wall shear stress. Analysis of the post-treatment flow field indicates that the increase in wall shear stress is due to the impingement of the basilar artery flow upon the aneurysm filling material and to the close proximity of a vortex tube to the artery wall. Calculation of the time-averaged wall shear stress shows that there is a region of the artery exposed to a level of wall shear stress that can cause severe damage to endothelial cells. The results of this study demonstrate that it is possible for a treatment procedure, which successfully excludes the aneurysm from the vascular system and leaves no aneurysm neck remnant, to elevate the hemodynamic stresses to levels that are injurious to the immediately adjacent vessel wall.« less

Determination of threshold and maximum operating electric stresses for selected high voltage insulations. Task 2: Investigation of oil-filled paper insulated cables

NASA Astrophysics Data System (ADS)

Sosnowski, M.; Eager, G. S., Jr.

1983-06-01

Threshold voltage of oil-impregnated paper insulated cables are investigaed. Experimental work was done on model cables specially manufactured for this project. The cables were impregnated with mineral and with synthetic oils. Standard impulse breakdown voltage tests and impulse voltage breakdown tests with dc prestressing were performed at room temperature and at 1000C. The most important result is the finding of very high level of threshold voltage stress for oil-impregnated paper insulated cables. This threshold voltage is approximately 1.5 times higher than the threshold voltage or crosslinked polyethylene insulated cables.

49 CFR 195.207 - Transportation of pipe.

Code of Federal Regulations, 2010 CFR

2010-10-01

... stress of 20 percent or more of SMYS, an operator may not use pipe having an outer diameter to wall... barge. In a pipeline operated at a hoop stress of 20 percent or more of SMYS, an operator may not use...

49 CFR 195.207 - Transportation of pipe.

Code of Federal Regulations, 2012 CFR

2012-10-01

... stress of 20 percent or more of SMYS, an operator may not use pipe having an outer diameter to wall... barge. In a pipeline operated at a hoop stress of 20 percent or more of SMYS, an operator may not use...

49 CFR 195.207 - Transportation of pipe.

Code of Federal Regulations, 2011 CFR

2011-10-01

... stress of 20 percent or more of SMYS, an operator may not use pipe having an outer diameter to wall... barge. In a pipeline operated at a hoop stress of 20 percent or more of SMYS, an operator may not use...

Intensive skills week for military medical students increases technical proficiency, confidence, and skills to minimize negative stress.

PubMed

Mueller, Genevieve; Hunt, Bonnie; Wall, Van; Rush, Robert; Molof, Alan; Schoeff, Jonathan; Wedmore, Ian; Schmid, James; Laporta, Anthony

2012-01-01

The effects of stress induced cortisol on learning and memory is well documented in the literature.1-3 Memory and learning are enhanced at low levels while high levels are detrimental. Repetitive training in stressful situations enables management of the stress response4 as demonstrated by the high intensity training military members undergo to prepare for tactical situations. Appropriate management of one?s stress response is critical in the medical field, as the negative effects of stress can potentially hinder life-saving procedures and treatments. This also applies to physicians-in-training as they learn and practice triage, emergency medicine, and surgical skills prior to graduation. Rocky Vista University?s Military Medicine Honor?s Track (MMHT) held a week long high-intensity emergency medicine and surgical Intensive Skills Week (ISW), facilitated by military and university physicians, to advance students? skills and maximize training using the Human Worn Partial Surgical Task Simulator (Cut Suit). The short-term goal of the ISW was to overcome negative stress responses to increase confidence, technical and non-technical knowledge, and skill in surgery and emergency medicine in an effort to improve performance as third-year medical students. The long-term goal was to enhance performance and proficiency in residency and future medical practice. The metrics for the short-term goals were the focus of this pilot study. Results show an increase in confidence and decrease in perceived stress as well as statistically significant improvements in technical and non-technical skills and surgical instrumentation knowledge throughout the week. There is a correlative benefit to physician and non-physician military personnel, especially Special Operations Forces (SOF) medical personnel, from developing and implementing similar training programs when live tissue or cadaver models are unavailable or unfeasible. 2012.

Mechanisms of Change: Testing how Preventative Interventions Impact Psychological and Physiological Stress Functioning in Mothers in Neglectful Families

PubMed Central

Toth, Sheree L.; Sturge-Apple, Melissa L.; Rogosch, Fred A.; Cicchetti, Dante

2015-01-01

The present study applies a multilevel approach to an examination of the effect of two randomized preventative interventions with mothers in neglectful families who are also contending with elevated levels of impoverishment and ecological risk. Specifically, we examined how participation in either Child-Parent Psychotherapy (CPP) or Psychoeducational Parenting (PPI) interventions was associated with reductions in maternal psychological parenting stress and in turn physiological stress system functioning when compared to mothers involved in standard community services (CS) as well as a demographic comparison group of nonmaltreating mothers (NC). The resulting group sizes in the current investigation were: CPP (n = 44), PPI (n = 34), CS (n = 27), and NC (n = 52). Mothers and infants who were 13-months of age were randomly assigned to intervention group at baseline. Mothers completed assessments on stress within the parenting role at baseline and post-intervention. Basal cortisol was sampled at post-intervention and 1-year follow-up. Latent difference score analyses examined change in these constructs over time. Results suggested that mothers within the CPP intervention experienced significant declines in child-related parenting stress while mothers in the PPI intervention reported declines in parent-related parenting stress. In turn, significant decreases in stress within the CPP mothers were further associated with adaptive basal cortisol functioning at 1-year post-intervention. Results highlight the value of delineating how participation in preventtive interventions aimed at ameliorating child maltreatment in neglectful families within the context of poverty may operate through improvements in psychological and physiological stress functioning. Findings are discussed with respect to the importance of multi-level assessments of intervention process and outcome. PMID:26535951

Assessment of the midflexion rotational laxity in posterior-stabilized total knee arthroplasty.

PubMed

Hino, Kazunori; Kutsuna, Tatsuhiko; Oonishi, Yoshio; Watamori, Kunihiko; Kiyomatsu, Hiroshi; Iseki, Yasutake; Watanabe, Seiji; Ishimaru, Yasumitsu; Miura, Hiromasa

2017-11-01

To evaluate changes in midflexion rotational laxity before and after posterior-stabilized (PS)-total knee arthroplasty (TKA). Twenty-nine knees that underwent PS-TKA were evaluated. Manual mild passive rotational stress was applied to the knees, and the internal-external rotational angle was measured automatically by a navigation system at 30°, 45°, 60°, and 90° of knee flexion. The post-operative internal rotational laxity was statistically significantly increased compared to the preoperative level at 30°, 45°, 60°, and 90° of flexion. The post-operative external rotational laxity was statistically significantly decreased compared to the preoperative level at 45° and 60° of flexion. The post-operative internal-external rotational laxity was statistically significantly increased compared to the preoperative level only at 30° of flexion. The preoperative and post-operative rotational laxity showed a significant correlation at 30°, 45°, 60°, and 90° of flexion. Internal-external rotational laxity increases at the initial flexion range due to resection of both the anterior or posterior cruciate ligaments and retention of the collateral ligaments in PS-TKA. Preoperative and post-operative rotational laxity indicated a significant correlation at the midflexion range. This study showed that a large preoperative rotational laxity increased the risk of a large post-operative laxity, especially at the initial flexion range in PS-TKA. III.

Potential oxidative stress in the bodies of electric arc welding operators: effect of photochemical smog.

PubMed

Zhu, You-Gen; Zhou, Jun-Fu; Shan, Wei-Ying; Zhou, Pei-Su; Tong, Gui-Zhong

2004-12-01

To investigate whether photochemical smog emitted during the process of electric arc welding might cause oxidative stress and potential oxidative damage in the bodies of welding operators. Seventy electric arc welding operators (WOs) and 70 healthy volunteers (HVs) were enrolled in a randomized controlled study design, in which the levels of vitamin C (VC) and vitamin E (VE) in plasma as well as the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), and the level of lipoperoxide (LPO) in erythrocytes were determined by spectrophotometry. Compared with the average values of the above experimental parameters in the HVs group, the average values of VC and VE in plasma as well as those of SOD, CAT and GPX in erythrocytes in the WOs group were significantly decreased (P < 0.005-0.0001), while the average value of LPO in erythrocytes in the WOs group was significantly increased (P < 0.0001). The findings from the partial correlation analysis on the controlling of age suggested that with a prolonged duration of exposure to photochemical smog the values of VC, VE, SOD, and GPX, except for CAT, in the WOs were decreased gradually (P < 0.05-0.005), the value of LPO in the WOs was increased gradually (P < 0.001), and that with the ozone dose increased in the air in each worksite VC, VE, SOD, CAT and GPX decreased (P < 0.005-0.001), but LPO increased (P < 0.001). The findings from the reliability analysis for the VC, VE, SOD, CAT, GPX, and LPO values which were used to reflect oxidative stress and potential oxidative damage in the WOs showed that the reliability coefficients' alpha (6 items) was 0.8021, P < 0.0001, and that the standardized item alpha was 0.9577, P < 0.0001. Findings in the present study suggest that there exists an oxidative stress induced by long-term exposure to photochemical smog in the bodies of WOs, thereby causing potential oxidative and lipoperoxidative damages in their bodies.

Predictors of expressive writing content and posttraumatic stress following a mass shooting.

PubMed

Reddy, Madhavi K; Seligowski, Antonia V; Rabenhorst, Mandy M; Orcutt, Holly K

2015-05-01

This study examined relations among experiential avoidance, state dissociation during writing, cognitive-emotional processing, and posttraumatic stress in the context of an expressive writing task among 58 undergraduate females who were students at a large midwestern university that had recently experienced a mass shooting. Experiential avoidance significantly predicted reported suppression during the writing task. Additionally, posttraumatic stress symptoms (PTSS) at the time of the writing task were significantly associated with state dissociation, suppression, and the use of positive emotion words during the writing. Finally, at the zero-order level, prospective PTSS were associated with state dissociation and suppression during the earlier writing task. However, in a full regression model, only experiential avoidance and PTSS at the time of the writing task significantly predicted prospective PTSS. Supplemental analyses suggest processes may operate differently across levels of exposure. Findings from the present study provide further support for the role of experiential avoidance, state dissociation during writing, and cognitive-emotional processing in predicting PTSS. Additionally, experiential avoidance may play an important role in how individuals use cognitive-emotional processing to narrate a traumatic event. (c) 2015 APA, all rights reserved).

Effect of geraniol on rat cardiomyocytes and its potential use as a cardioprotective natural compound.

PubMed

Crespo, R; Wei, K; Rodenak-Kladniew, B; Mercola, M; Ruiz-Lozano, P; Hurtado, C

2017-03-01

Reactive oxygen species (ROS) are generated in the ischaemic myocardium especially during early reperfusion and affect myocardial function and viability. Monoterpenes have been proposed to play beneficial roles in diverse physiological systems; however, the mechanisms of action remain largely unknown. This study aims to assess the effect of monoterpene geraniol (GOH) on neonatal rat ventricular cardiomyocytes (NRVCs) subjected to oxidative stress. We used an in vitro model of hypoxia-reoxygenation. Cardioprotective (AMPK) and cardiotoxic (ERK1/2, ROS) signaling indicators were measured. Assays were performed by fluorogenic probes, MTT assays and Western-blots. We determined that the addition of GOH (5-200μM) to cultured normoxic and hypoxic-NRVCs diminished the endogenous production of ROS in stressed cardiomyocytes. We observed that GOH treatment increased pAMPK levels and decreased pERK1/2 levels in cultured NRVCs. This report suggests that GOH is a candidate cardioprotective natural compound that operates by blunting the oxidative stress signaling that is normally induced by hypoxia-reoxygenation. Copyright © 2017 Elsevier Inc. All rights reserved.

Irradiation creep and swelling of AISI 316 to exposures of 130 dpa at 385?400$deg;C

NASA Astrophysics Data System (ADS)

Garner, F. A.; Porter, D. L.

1988-07-01

The creep and swelling of AISI 316 stainless steel have been studied at 385 to 400°C in EBR-II to doses of 130 dpa. Most creep capsules were operated at constant stress and temperature but mid-life changes in these variables were also made. This paper concentrates on the behavior of the 20% cold-worked condition but five other conditions were also studied. Swelling at ⩽ 400° C was found to lose the sensitivity to stress exhibited at higher temperatures while the creep rate was found to retain linear dependencies on both stress and swelling rate. The creep coefficients extracted at 400°C agree with those found in other experiments conducted at higher temperatures. In the temperature range of ⩽ 400° C, swelling is in the recombinationdominated regime and the swelling rate falls strongly away from the ~1%/dpa rate observed at higher temperatures. These lower rates of creep and swelling, coupled with the attainment of high damage levels without failure, encourage the use of AISI 316 in the construction of water-cooled fusion first walls operating at temperatures below 400°C.

Relationship between general intelligence, emotional intelligence, stress levels and stress reactivity.

PubMed

Singh, Yogesh; Sharma, Ratna

2012-07-01

Stressful life events and daily life stresses have both deleterious and cumulative effects on human body. In several studies, stress has been shown to affect various parameter of higher mental function like attention, concentration, learning and memory. Present study was designed to explore the relationship among GI level, EI level, psychological stress levels and acute stress reactivity in young normal healthy subjects. The study was conducted on thirty four healthy male student volunteers to study a) acute stress reactivity in subjects with varying levels of General Intelligence (GI) and Emotional Intelligence (EI) and b) correlation between GI, EI, acute stress and perceived stress. Baseline GI and EI and acute stress and perceived stress scores were measured by standard assessment scales. Using median value of GI and EI scores as cutoff values, subjects were categorized into four groups. Among different GI-EI groups, acute stress reactivity was similar but salivary Cortisol (especially post stressor level) and perceived stress level was a differentiating factor. High level of EI was associated inversely with acute and chronic perceived stress level. Significant correlation was found between acute and chronic perceived stress levels. Level of general intelligence showed no relation to acute or chronic stress levels as well as acute stress reactivity. The differences in various groups of GI and EI had no effect on the baseline and post stress performance on Sternberg memory test and all the three conditions of Stroop test. In conclusion emotional intelligence as an attribute is better suited to handle day to day acute stress and chronic perceived stress.

Thermal stress characterization using the electro-mechanical impedance method

NASA Astrophysics Data System (ADS)

Zhu, Xuan; Lanza di Scalea, Francesco; Fateh, Mahmood

2017-04-01

This study examines the potential of the Electro-Mechanical Impedance (EMI) method to provide an estimation of the developed thermal stress in constrained bar-like structures. This non-invasive method features the easiness of implementation and interpretation, while it is notoriously known for being vulnerable to environmental variability. A comprehensive analytical model is proposed to relate the measured electric admittance signatures of the PZT element to temperature and uniaxial stress applied to the underlying structure. The model results compare favorably to the experimental ones, where the sensitivities of features extracted from the admittance signatures to the varying stress levels and temperatures are determined. Two temperature compensation frameworks are proposed to characterize the thermal stress states: (a) a regression model is established based on temperature-only tests, and the residuals from the thermal stress tests are then used to isolate the stress measurand; (b) the temperature-only tests are decomposed by Principle Components Analysis (PCA) and the feature vectors of the thermal stress tests are reconstructed after removal of the temperaturesensitive components. For both methods, the features were selected based on their performance in Receiver Operating Characteristic (ROC) curves. Experimental results on the Continuous Welded Rails (CWR) are shown to demonstrate the effectiveness of these temperature compensation methods.

Effect of pertussis toxin pretreated centrally on blood glucose level induced by stress.

PubMed

Suh, Hong-Won; Sim, Yun-Beom; Park, Soo-Hyun; Sharma, Naveen; Im, Hyun-Ju; Hong, Jae-Seung

2016-09-01

In the present study, we examined the effect of pertussis toxin (PTX) administered centrally in a variety of stress-induced blood glucose level. Mice were exposed to stress after the pretreatment of PTX (0.05 or 0.1 µg) i.c.v. or i.t. once for 6 days. Blood glucose level was measured at 0, 30, 60 and 120 min after stress stimulation. The blood glucose level was increased in all stress groups. The blood glucose level reached at maximum level after 30 min of stress stimulation and returned to a normal level after 2 h of stress stimulation in restraint stress, physical, and emotional stress groups. The blood glucose level induced by cold-water swimming stress was gradually increased up to 1 h and returned to the normal level. The intracerebroventricular (i.c.v.) or intrathecal (i.t.) pretreatment with PTX, a Gi inhibitor, alone produced a hypoglycemia and almost abolished the elevation of the blood level induced by stress stimulation. The central pretreatment with PTX caused a reduction of plasma insulin level, whereas plasma corticosterone level was further up-regulated in all stress models. Our results suggest that the hyperglycemia produced by physical stress, emotional stress, restraint stress, and the cold-water swimming stress appear to be mediated by activation of centrally located PTX-sensitive G proteins. The reduction of blood glucose level by PTX appears to due to the reduction of plasma insulin level. The reduction of blood glucose level by PTX was accompanied by the reduction of plasma insulin level. Plasma corticosterone level up-regulation by PTX in stress models may be due to a blood glucose homeostatic mechanism.

Electrical and mechanical characteristics of fully transparent IZO thin-film transistors on stress-relieving bendable substrates

NASA Astrophysics Data System (ADS)

Park, Sukhyung; Cho, Kyoungah; Oh, Hyungon; Kim, Sangsig

2016-10-01

In this study, we report the electrical and mechanical characteristics of fully transparent indium zinc oxide (IZO) thin-film transistors (TFTs) fabricated on stress-relieving bendable substrates. An IZO TFT on a stress-relieving substrate can operate normally at a bending radius of 6 mm, while an IZO TFT on a normal plastic substrate fails to operate normally at a bending radius of 15 mm. A plastic island with high Young's modulus embedded on a soft elastomer layer with low Young's modulus plays the role of a stress-relieving substrate for the operation of the bent IZO TFT. The stress and strain distributions over the IZO TFT will be analyzed in detail in this paper.

Thermo-Mechanical and Electrochemistry Modeling of Planar SOFC Stacks

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

Khaleel, Mohammad A.; Recknagle, Kurtis P.; Lin, Zijing

2002-12-01

Modeling activities at PNNL support design and development of modular SOFC systems. The SOFC stack modeling capability at PNNL has developed to a level at which planar stack designs can be compared and optimized for startup performance. Thermal-fluids and stress modeling is being performed to predict the transient temperature distribution and to determine the thermal stresses based on the temperature distribution. Current efforts also include the development of a model for calculating current density, cell voltage, and heat production in SOFC stacks with hydrogen or other fuels. The model includes the heat generation from both Joule heating and chemical reactions.more » It also accounts for species production and destruction via mass balance. The model is being linked to the finite element code MARC to allow for the evaluation of temperatures and stresses during steady state operations.« less

Elevated temperatures are associated with stress in rooftop-nesting Common Nighthawk (Chordeiles minor) chicks.

PubMed

Newberry, Gretchen N; Swanson, David L

2018-01-01

Grasslands and riparian forests in southeastern South Dakota have been greatly reduced since historical times, primarily due to conversion to row-crop agriculture. Common Nighthawk ( Chordeiles minor ) nesting habitat includes grasslands, open woodlands and urban rooftops, but nesting sites in southeastern South Dakota are confined to rooftops, as natural nesting habitat is limited. Nighthawks nesting on exposed rooftop habitats may encounter thermal conditions that increase operative temperatures relative to vegetated land cover types. Mean humidity has increased and mean wind speed and cloud cover have decreased during the nighthawk breeding season from 1948 to 2016 in southeastern South Dakota. These changes might contribute to increasing operative temperatures at exposed rooftop nest sites and this could influence chick condition. We studied nest micro-climate and the plasma stress response for 24 rooftop-nesting nighthawk chicks from 17 nests during 2015 and 2016. High humidity prior to blood collection reduced both baseline and stress-induced plasma corticosterone (CORT). In contrast, high maximum temperatures during the day before sampling increased stress-induced CORT. The magnitude of the chick stress response was significantly negatively related to maximum wind speed for the week prior to CORT measurement. Other weather and micro-climate variables were not significant effectors of CORT metrics. Most chicks had low baseline CORT and were able to mount a stress response, but a subset of chicks ( n = 4) showed elevated baseline CORT and a negative association between the magnitude of stress response and ambient temperature. For this subset, mean ambient temperature for the day before sampling was significantly higher (2.3°C) than for chicks with typical baseline CORT levels. These data suggest that regional climate change trends could affect the ability of nighthawk chicks to mount a stress response, which, in turn, might influence the susceptibility of nighthawk chicks to climate change in the Northern Prairie region.

[TVT tape usage in the treatment of stress urinary incontinence].

PubMed

Włodarczyk, Bogumił; Szyłło, Krzysztof; Kamer-Bartosińska, Anna; Lewy, Jarosław

2003-10-01

Stress urinary incontinence is one of the most common gynecological complains. The frequency of its occurrence is from 12 to 25 and even 60%. It is most often observed in patients after menopause, but in a few percent is also found in twenty and thirty years old women. During several years of searching the effective methods of stress urinary incontinence treatment, many operative techniques have been worked out, but none of them became a perfect one. The operation with the use of TVT tape is one of the newest methods of the stress urinary incontinence treatment. The aim of our study was the attempt of the estimation the TVT operation effectiveness in the treatment of stress urinary incontinence in women treated in Surgical Gynecology Department of Polish Mother Health Centre Research Institute in years 2000-2002. Performed analysis of 60 patients at the age between 38 and 76 years revealed that stress urinary incontinence symptoms regressed after TVT operation, as evaluated 7 days after the procedure. In 51.7% of patients anterior colpoplasty or colpoperineoplasty was performed simultaneously to TVT operation. Control studies were performed a month and six months after the operation. Recurrence of the symptoms was observed in 11.7% of the patients. Revealed data let us show that the efficacy of this procedure is very high and reaches 88.3%.

Looking After the Clinical and Social Support Needs of Military Families Impacted by Operational Stress Injuries

DTIC Science & Technology

2006-04-01

Injury Social Support program (OSISS), created in 2001, offers social support services through an organized and formalized national peer support network...Forces by raising awareness and understanding and creating acceptance toward psychological injuries. Providing social support through a formal ...poorer psychological adjustment, greater levels of familial conflict and interpersonal violence, and increased caregiver burden. These partners also

The Eastern Renewable Generation Integration Study: Insights on System Stress: Preprint

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

Bloom, Aaron; Novacheck, Josh

The Eastern Renewable Generation Integration Study (ERGIS) explores the operational impacts of the wide spread adoption of wind and solar photovoltaics (PV) resources in North America's Eastern and Quebec Interconnections. We explore the impact of large scale adoption of wind and solar generation on the unit commitment and economic dispatch of the largest coordinated power system in the world by simulating hourly and five-minute operations. Using NREL's high-performance computing capabilities and new methodologies to model operations, we found that the modeled system, as simulated with evolutionary change in 2026, could balance the variability and uncertainty of wind and solar PVmore » at a five-minute level under a variety of conditions. Our simulations achieve instantaneous penetrations that exceed 50% of load while meeting an annual penetration of 30% on an energy basis. The system meets balanced load and supply in all intervals, with modest curtailment, using technologies and practices that are widely available today. However, a variety of the conditions present in these simulations deviate substantially from historical practice. In this work, we analyze potentially stressful system conditions that occur in the simulations and identify opportunities for innovation, regulatory reform, and changes in operating practices that require further analysis to enable the transition to a system with more wind and solar PV.« less

A Global Perspective on Warmer Droughts as a Key Driver of Forest Disturbances and Tree Mortality (Invited)

NASA Astrophysics Data System (ADS)

Allen, C. D.

2013-12-01

Recent global warming, in concert with episodic droughts, is causing elevated levels of both chronic and acute forest water stress across large regions. Such increases in water stress affect forest dynamics in multiple ways, including by amplifying the incidence and severity of many significant forest disturbances, particularly drought-induced tree mortality, wildfire, and outbreaks of damaging insects and diseases. Emerging global-scale patterns of drought-related forest die-off are presented, including a newly updated map overview of documented drought- and heat-induced tree mortality events from around the world, demonstrating the vulnerability of all major forest types to forest drought stress, even in typically wet environments. Comparative patterns of drought stress and associated forest disturbances are reviewed for several regions (southwestern Australia, Inner Asia, western North America, Mediterranean Basin), including interactions among climate and various disturbance processes. From the Southwest USA, research is presented that derives a tree-ring-based Forest Drought Stress Index (FDSI) for the most regionally-widespread conifer species (Pinus edulis, Pinus ponderosa, and Pseudotsuga menziesii), demonstrating recent escalation of FDSI to extreme levels relative to the past 1000 years, due to both drought and especially warming. This new work further highlights strong correlations between drought stress and amplified forest disturbances (fire, bark beetle outbreaks), and projects that by CE 2050 anticipated regional warming will cause mean FDSI values to reach historically unprecedented levels that may exceed thresholds for the survival of current tree species in large portions of their current range in the Southwest. Similar patterns of recent climate-amplified forest disturbance risk are apparent from a variety of relatively dry regions across this planet, and given climate projections for substantially warmer temperatures and greater drought stress for many areas globally, the growing water-stress risks to forest health in such regions are becoming clearer. However, the effects of drought stress on forest dynamics are ameliorated through diverse compensatory and resilience-enhancing mechanisms and processes which operate at scales ranging from intracellular tree physiologies and individual tree developmental and morphological adjustments to species population-level demographic and genetic responses to forest stand-level structural and compositional responses up to landscape-scale tree host-insect pest outbreak dynamics and forest-climate ecohydrological feedbacks. In addition, significant uncertainties exist regarding how various other global atmospheric changes (e.g., CO2 enrichment, increased N deposition, and elevated surface-level ozone) will interact with the world's diverse spectrum of tree species to also affect global forest dynamics. Research efforts to address such core scientific uncertainties associated with modeling drought-induced tree mortality and resultant forest dynamics will be discussed.

Noninvasive evaluation of mental stress using by a refined rough set technique based on biomedical signals.

PubMed

Liu, Tung-Kuan; Chen, Yeh-Peng; Hou, Zone-Yuan; Wang, Chao-Chih; Chou, Jyh-Horng

2014-06-01

Evaluating and treating of stress can substantially benefits to people with health problems. Currently, mental stress evaluated using medical questionnaires. However, the accuracy of this evaluation method is questionable because of variations caused by factors such as cultural differences and individual subjectivity. Measuring of biomedical signals is an effective method for estimating mental stress that enables this problem to be overcome. However, the relationship between the levels of mental stress and biomedical signals remain poorly understood. A refined rough set algorithm is proposed to determine the relationship between mental stress and biomedical signals, this algorithm combines rough set theory with a hybrid Taguchi-genetic algorithm, called RS-HTGA. Two parameters were used for evaluating the performance of the proposed RS-HTGA method. A dataset obtained from a practice clinic comprising 362 cases (196 male, 166 female) was adopted to evaluate the performance of the proposed approach. The empirical results indicate that the proposed method can achieve acceptable accuracy in medical practice. Furthermore, the proposed method was successfully used to identify the relationship between mental stress levels and bio-medical signals. In addition, the comparison between the RS-HTGA and a support vector machine (SVM) method indicated that both methods yield good results. The total averages for sensitivity, specificity, and precision were greater than 96%, the results indicated that both algorithms produced highly accurate results, but a substantial difference in discrimination existed among people with Phase 0 stress. The SVM algorithm shows 89% and the RS-HTGA shows 96%. Therefore, the RS-HTGA is superior to the SVM algorithm. The kappa test results for both algorithms were greater than 0.936, indicating high accuracy and consistency. The area under receiver operating characteristic curve for both the RS-HTGA and a SVM method were greater than 0.77, indicating a good discrimination capability. In this study, crucial attributes in stress evaluation were successfully recognized using biomedical signals, thereby enabling the conservation of medical resources and elucidating the mapping relationship between levels of mental stress and candidate attributes. In addition, we developed a prototype system for mental stress evaluation that can be used to provide benefits in medical practice. Copyright © 2014. Published by Elsevier B.V.

Thermal-stress analysis of IFMIF target back-wall made of reduced-activation ferritic steel and austenitic stainless steel

NASA Astrophysics Data System (ADS)

Ida, Mizuho; Chida, Teruo; Furuya, Kazuyuki; Wakai, Eiichi; Nakamura, Hiroo; Sugimoto, Masayoshi

2009-04-01

For long time operation of a liquid lithium target of the International Fusion Materials Irradiation Facility, annual replacement of a back-wall, a part of the flow channel, is planned, since the target suffers neutron damage of more than 50 dpa/fpy. Considering irradiation/activation conditions, remote weld on stainless steel 316L between a back-wall and a target assembly was employed. Furthermore, dissimilar weld between the 316L and a reduced-activation ferritic/martensitic steel F82H in the back-wall was employed. The objective of this study is to clarify structures and materials of the back-wall with acceptable thermal-stress under nuclear heating. Thermal-stress analysis was done using a code ABAQUS and data of the nuclear heating. As a result, thermal-stress in the back-wall is acceptable level, if thickness of the stress-mitigation part is more than 5 mm. With results of the analysis, necessity of material data for F82H and 316L under conditions of irradiation tests and mechanical tests are clarified.

Evaluating penalized logistic regression models to predict Heat-Related Electric grid stress days

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

Bramer, Lisa M.; Rounds, J.; Burleyson, C. D.

Understanding the conditions associated with stress on the electricity grid is important in the development of contingency plans for maintaining reliability during periods when the grid is stressed. In this paper, heat-related grid stress and the relationship with weather conditions were examined using data from the eastern United States. Penalized logistic regression models were developed and applied to predict stress on the electric grid using weather data. The inclusion of other weather variables, such as precipitation, in addition to temperature improved model performance. Several candidate models and combinations of predictive variables were examined. A penalized logistic regression model which wasmore » fit at the operation-zone level was found to provide predictive value and interpretability. Additionally, the importance of different weather variables observed at various time scales were examined. Maximum temperature and precipitation were identified as important across all zones while the importance of other weather variables was zone specific. In conclusion, the methods presented in this work are extensible to other regions and can be used to aid in planning and development of the electrical grid.« less

Evaluating penalized logistic regression models to predict Heat-Related Electric grid stress days

DOE PAGES

Bramer, Lisa M.; Rounds, J.; Burleyson, C. D.; ...

2017-09-22

Understanding the conditions associated with stress on the electricity grid is important in the development of contingency plans for maintaining reliability during periods when the grid is stressed. In this paper, heat-related grid stress and the relationship with weather conditions were examined using data from the eastern United States. Penalized logistic regression models were developed and applied to predict stress on the electric grid using weather data. The inclusion of other weather variables, such as precipitation, in addition to temperature improved model performance. Several candidate models and combinations of predictive variables were examined. A penalized logistic regression model which wasmore » fit at the operation-zone level was found to provide predictive value and interpretability. Additionally, the importance of different weather variables observed at various time scales were examined. Maximum temperature and precipitation were identified as important across all zones while the importance of other weather variables was zone specific. In conclusion, the methods presented in this work are extensible to other regions and can be used to aid in planning and development of the electrical grid.« less

Weightbearing vs Gravity Stress Radiographs for Stability Evaluation of Supination-External Rotation Fractures of the Ankle.

PubMed

Seidel, Angela; Krause, Fabian; Weber, Martin

2017-07-01

Isolated lateral malleolar fractures may result from a supination-external rotation (SER) injury of the ankle. Stable fractures maintain tibiotalar congruence due to competent medial restraints and can be treated nonoperatively with excellent functional results and long-term prognosis. Stability might be assessed with either stress radiographs or weightbearing radiographs. A consecutive series of patients with closed SER fractures (presumed AO 44-B1) were prospectively enrolled from 2008 to 2015. Patients with clearly unstable fractures (medial clear space more than 7 mm) on the initial nonweightbearing radiograph were excluded and operated on. All other patients were examined with a gravity stress and a weightbearing anteroposterior radiograph. Borderline instability of the fracture was assumed when the medial clear space was 4 to 7 mm. Those were treated nonoperatively. Of 104 patients with isolated lateral malleolar fractures of the SER type, 14 patients were treated operatively because of clear instability (displacement) on the initial radiographs. Of the nonoperative patients, 44 patients demonstrated borderline instability on the gravity stress but stability on the weightbearing radiograph ("gravity borderline"); the remaining 46 were stable in both tests ("gravity stable"). At an average follow-up of 23 months, no significant differences were seen in the American Orthopaedic Foot & Ankle Society hindfoot score (92 points gravity-borderline group vs 93 points gravity-unstable group), the Foot Functional Index score (11 vs 10 points), the Short Form 36 (SF-36) physical component (86 vs 85 points), and SF-36 mental component (84 vs 81 points). Radiographically, all fractures had healed with anatomic congruity of the ankle. Weightbearing radiographs provided a reliable basis to decide about stability and nonoperative treatment in isolated lateral malleolar fractures of the SER type with excellent clinical and radiographic outcome at short-term follow-up. Gravity stress radiographs appear to overrate the need for operative treatment. Level III, prospective comparative study.

Solute segregation kinetics and dislocation depinning in a binary alloy

NASA Astrophysics Data System (ADS)

Dontsova, E.; Rottler, J.; Sinclair, C. W.

2015-06-01

Static strain aging, a phenomenon caused by diffusion of solute atoms to dislocations, is an important contributor to the strength of substitutional alloys. Accurate modeling of this complex process requires both atomic spatial resolution and diffusional time scales, which is very challenging to achieve with commonly used atomistic computational methods. In this paper, we use the recently developed "diffusive molecular dynamics" (DMD) method that is capable of describing the kinetics of the solute segregation process at the atomic level while operating on diffusive time scales in a computationally efficient way. We study static strain aging in the Al-Mg system and calculate the depinning shear stress between edge and screw dislocations and their solute atmospheres formed for various waiting times with different solute content and for a range of temperatures. A simple phenomenological model is also proposed that describes the observed behavior of the critical shear stress as a function of segregation level.

Determination of internal controls for quantitative gene expression of Isochrysis zhangjiangensis at nitrogen stress condition

NASA Astrophysics Data System (ADS)

Wu, Shuang; Zhou, Jiannan; Cao, Xupeng; Xue, Song

2016-02-01

Isochrysis zhangjiangensis is a potential marine microalga for biodiesel production, which accumulates lipid under nitrogen limitation conditions, but the mechanism on molecular level is veiled. Quantitative real-time polymerase chain reaction (qPCR) provides the possibility to investigate the gene expression levels, and a valid reference for data normalization is an essential prerequisite for firing up the analysis. In this study, five housekeeping genes, actin (ACT), α-tubulin (TUA), ß-tubulin (TUB), ubiquitin (UBI), 18S rRNA (18S) and one target gene, diacylglycerol acyltransferase (DGAT), were used for determining the reference. By analyzing the stabilities based on calculation of the stability index and on operating the two types of software, geNorm and bestkeeper, it showed that the reference genes widely used in higher plant and microalgae, such as UBI, TUA and 18S, were not the most stable ones in nitrogen-stressed I. zhangjiangensis, and thus are not suitable for exploring the mRNA expression levels under these experimental conditions. Our results show that ACT together with TUB is the most feasible internal control for investigating gene expression under nitrogen-stressed conditions. Our findings will contribute not only to future qPCR studies of I. zhangjiangensis, but also to verification of comparative transcriptomics studies of the microalgae under similar conditions.

Characterization of Mechanical Properties and Residual Stress in API 5L X80 Steel Welded Joints

NASA Astrophysics Data System (ADS)

de Sousa Lins, Amilton; de Souza, Luís Felipe Guimarães; Fonseca, Maria Cindra

2018-01-01

The use of high-strength and low-alloy steels, high design factors and increasingly stringent safety requirements have increased the operating pressure levels and, consequently, the need for further studies to avoid and prevent premature pipe failure. To evaluate the possibility of improving productivity in manual arc welding of this type of steel, this work characterizes the mechanical properties and residual stresses in API 5L X80 steel welded joints using the SMAW and FCAW processes. The residual stresses were analyzed using x-ray diffraction with the sin2 ψ method at the top and root of the welded joints in the longitudinal and transverse directions of the weld bead. The mechanical properties of the welded joints by both processes were characterized in terms of tensile strength, impact toughness and Vickers microhardness in the welded and shot peening conditions. A predominantly compressive residual stress was found, and shot peening increased the tensile strength and impact toughness in both welded joints.

Genomic Instability in Human Pluripotent Stem Cells Arises from Replicative Stress and Chromosome Condensation Defects.

PubMed

Lamm, Noa; Ben-David, Uri; Golan-Lev, Tamar; Storchová, Zuzana; Benvenisty, Nissim; Kerem, Batsheva

2016-02-04

Human pluripotent stem cells (hPSCs) frequently acquire chromosomal aberrations such as aneuploidy in culture. These aberrations progressively increase over time and may compromise the properties and clinical utility of the cells. The underlying mechanisms that drive initial genomic instability and its continued progression are largely unknown. Here, we show that aneuploid hPSCs undergo DNA replication stress, resulting in defective chromosome condensation and segregation. Aneuploid hPSCs show altered levels of actin cytoskeletal genes controlled by the transcription factor SRF, and overexpression of SRF rescues impaired chromosome condensation and segregation defects in aneuploid hPSCs. Furthermore, SRF downregulation in diploid hPSCs induces replication stress and perturbed condensation similar to that seen in aneuploid cells. Together, these results suggest that decreased SRF expression induces replicative stress and chromosomal condensation defects that underlie the ongoing chromosomal instability seen in aneuploid hPSCs. A similar mechanism may also operate during initiation of instability in diploid cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Increased carboxyhemoglobin level during liver resection with inflow occlusion.

PubMed

Godai, Kohei; Hasegawa-Moriyama, Maiko; Kuniyoshi, Tamotsu; Matsunaga, Akira; Kanmura, Yuichi

2013-04-01

Controlling stress responses associated with ischemic changes due to bleeding and ischemia/reperfusion injury is essential for anesthetic management. Endogenous carboxyhemoglobin (COHb) is produced in the oxidative degradation of heme proteins by the stress-response enzyme heme oxygenase. Although the COHb level is elevated in critically ill patients, changes in endogenous COHb during anesthesia have not been well investigated. Therefore, we evaluated changes in endogenous COHb levels in patients undergoing liver resections with inflow occlusion. Levels of COHb were significantly increased after the Pringle maneuver. The inflow occlusion time in patients with increased COHb after the Pringle maneuver (∆COHb > 0.3 %) was significantly longer than in patients without increased COHb (∆COHb < 0.3 %) (P = 0.01). In addition, COHb changes were correlated with inflow occlusion time (P = 0.005, R(2) = 0.21). Neither total blood loss, transfusion volume of packed red blood cells, operation time, nor anesthetic time differed between patients with and without increased COHb. The results indicated that endogenous COHb levels were increased by inflow occlusion in patients undergoing liver resections, which suggests that changes in COHb may correlate with hepatic ischemia/reperfusion injury induced by inflow occlusion.

Peculiarities of Thermal Treatment of Monolithic Reinforced Concrete Structures

NASA Astrophysics Data System (ADS)

Kuchin, V. N.; Shilonosova, N. V.

2017-11-01

A mathematical program has been developed that allows one to determine the parameters of heat treatment of monolithic structures. One of the quality indicators of monolithic reinforced concrete structures is the level of temperature stresses arising in the process of heat treatment and further operation of structures. In winter at heat treatment the distribution of temperatures along the cross-section of the structure is uneven. A favorable thermo-stressed state in a concrete massif occurs when using the preheating method, providing the concrete temperature in the center of the structure is greater than at the periphery. In this case, after the strength is set and the temperature is later equalized along the cross-section, the central part of the structure tends to decrease its dimensions more but the extreme zones prevent it. Therefore, the center is in a state of tension, and the extreme zones on the periphery are compressed. In compressed concrete there is a lesser chance of cracks or defects. The temperature gradient over the section of the structure, the stress in the concrete and its strength are determined. When calculating the temperature and strength fields, the stress level was determined - a value equal to the ratio of the tensile stresses in the section under consideration to the tensile strength of the concrete in this section at the same time. The nature of the change in stress level is determined by the massive structure and power of the formwork heaters. It is shown that under unfavorable conditions the stress level is close to the critical value. The greatest temperature gradient occurs in the outer layers adjacent to the heating formwork. A technology for concrete conditioning is proposed which makes it possible to reduce the temperature stresses along the cross-section of the structure. The time for concrete conditioning in the formwork is reduced. In its turn, it further reduces labor costs and the cost of concrete work along with the cost of heat treatment. The authors conduct the technical and economic comparison of heat treatment options for the structures. The duration of monolithic structures erection with the use of combined heat treatment decreases in comparison with the method of peripheral heating. The economic effect consists of the reduction of the cost to organize and perform temperature control, insulation, electricity.

A d-dimensional stress tensor for Minkd+2 gravity

NASA Astrophysics Data System (ADS)

Kapec, Daniel; Mitra, Prahar

2018-05-01

We consider the tree-level scattering of massless particles in ( d+2)-dimensional asymptotically flat spacetimes. The S -matrix elements are recast as correlation functions of local operators living on a space-like cut ℳ d of the null momentum cone. The Lorentz group SO( d + 1 , 1) is nonlinearly realized as the Euclidean conformal group on ℳ d . Operators of non-trivial spin arise from massless particles transforming in non-trivial representations of the little group SO( d), and distinguished operators arise from the soft-insertions of gauge bosons and gravitons. The leading soft-photon operator is the shadow transform of a conserved spin-one primary operator J a , and the subleading soft-graviton operator is the shadow transform of a conserved spin-two symmetric traceless primary operator T ab . The universal form of the soft-limits ensures that J a and T ab obey the Ward identities expected of a conserved current and energy momentum tensor in a Euclidean CFT d , respectively.

Operation Joint Guard (SFOR) Bosnia. Assessment of Operational Stress and Adaptive Coping Mechanisms of Soldiers

DTIC Science & Technology

1998-03-01

married, 3 children, \\ more than two years w/company J V ^ I am constantly placed in an ethical dilemmas daily in front of my soldiers. I do...and lessons learned are presented . 14. SUBJECT TERMS Bosnia, Operation Joint Guard, Operation Joint Endeavor, Peacekeeping, Stress, Psychological...keeping operations present challenging environments to any military organization and its soldiers. Soldiers will often be required to perform their

Study of ethane level in exhaled breath in patients with age-related macular degeneration: preliminary study.

PubMed

Cagini, C; Giordanelli, A; Fiore, T; Giardinieri, R; Malici, B; De Medio, G E; Pelli, M A; De Bellis, F; Capodicasa, E

2011-01-01

A variety of factors have been implicated in the pathogenesis of age-related macular degeneration (ARMD), and oxidative stress plays an important role in the onset and progression of the disease. Breath ethane is now considered a specific and non-invasive test for determining and monitoring the trend of lipid peroxidation and free radical-induced damage in vivo. This test provides an index of the patients' overall oxidative stress level. We evaluated the breath ethane concentration in exhaled air in patients with advanced ARMD. In this study, we enrolled 13 patients with advanced ARMD and a control group, and a breath analysis was carried out by gas chromatography. The mean ethane level in the ARMD patients was 0.82 ± 0.93 nmol/l (range: 0.01-2.7 nmol/l) and the mean ethane value in the control group was 0.12 ± 0.02 nmol/l (range: 0.08-0.16 nmol/l). The difference between the values of the 2 groups was statistically significant (p < 0.005). Receiver operating characteristic analysis showed an elevated area under the curve (0.831; 95% CI: 0.634-0.948), with a significance level of p < 0.0014 (area = 0.5). These preliminary results seem to indicate that breath ethane levels are higher in most patients with ARMD. The breath ethane test could thus be a useful method for evaluating the level of oxidative stress in patients with ARMD. To our knowledge, there are no data on this type of analysis applied to ARMD. Copyright © 2011 S. Karger AG, Basel.

Stress-induced changes of neurosteroid profiles in rat brain and plasma under immobilized condition.

PubMed

Park, Myeong Hyeon; Rehman, Shaheed Ur; Kim, In Sook; Choi, Min Sun; Yoo, Hye Hyun

2017-05-10

In this study, various neurosteroids in brain and plasma were simultaneously determined using liquid chromatography-tandem mass spectrometry and their profile changes in a stress-induced rats were investigated. The investigated neurosteroids are as follows: progesterone (P4), 5α-dihydroprogesterone (5α-DHP), 5β-dihydroprogesterone, estrone, androstenedione (AE), cortisol, cortisone, corticosterone (CORT), dehydroepiandrosterone (DHEA), pregnanolone (3α,5β-THP), allopregnanolone (ALLO), 11-deoxycorticosterone (DOC), 11-deoxycortisol, pregnenolone (PREG), and 5α/5β-tetrahydrodeoxycorticosterone (5α/5β-THDOC). Brain and plasma samples were processed using solid-phase extraction with methanol and acetic acid (99:1), and derivatized with a hydroxylamine reagent. Separation was achieved within 13min at a flow rate of 0.4mL/min with a C18 column (3.0×50mm, 2.7μm). The triple quadrupole mass spectrometer was operated in the positive electrospray ionization mode. Using this method, the neurosteroid level variation was quantitated and investigated in the brain and plasma upon immobilization stress in rats. As a result, AE, CORT, DOC, P4, 5α-DHP, 5α/5β-THDOC, DHEA, 3α,5β-THP, ALLO, and PREG levels were significantly altered in both the brain and plasma samples when stress was induced. These findings demonstrated that stress leads to the alteration of the GABAergic neurosteroid profile. The present results will be helpful for furthering an understanding of the role of neurosteroids in stressed conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of yohimbine on reinstatement of operant responding in rats is dependent on cue contingency but not food reward history.

PubMed

Chen, Yu-Wei; Fiscella, Kimberly A; Bacharach, Samuel Z; Tanda, Gianluigi; Shaham, Yavin; Calu, Donna J

2015-07-01

Yohimbine is an alpha-2 adrenoceptor antagonist that has been used in numerous studies as a pharmacological stressor in rodents, monkeys and humans. Recently, yohimbine has become the most common stress manipulation in studies on reinstatement of drug and food seeking. However, the wide range of conditions under which yohimbine promotes reward seeking is significantly greater than that of stressors like intermittent footshock. Here, we addressed two fundamental questions regarding yohimbine's effect on reinstatement of reward seeking: (1) whether the drug's effect on operant responding is dependent on previous reward history or cue contingency, and (2) whether yohimbine is aversive or rewarding under conditions typically used in reinstatement studies. We also used in vivo microdialysis to determine yohimbine's effect on dopamine levels in nucleus accumbens (NAc) and medial prefrontal cortex (mPFC). We found that the magnitude of yohimbine-induced (0.5, 1.0, 2.0 mg/kg) operant responding during the reinstatement tests was critically dependent on the contingency between lever pressing and discrete tone-light cue delivery but not the previous history with food reward during training. We also found that yohimbine (2 mg/kg) did not cause conditioned place aversion. Finally, we found that yohimbine modestly increased dopamine levels in mPFC but not NAc. Results suggest that yohimbine's effects on operant responding in reinstatement studies are likely independent of the history of contingent self-administration of food or drug rewards and may not be related to the commonly assumed stress-like effects of yohimbine. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Unique construction makes interferometer insensitive to mechanical stresses

NASA Technical Reports Server (NTRS)

Beer, R.

1965-01-01

Michelson-type interferometer with a cat-eye reflector operates effectively even in the presence of random mechanical stresses. A cubical beamsplitter with dichroic surfaces permits operation in infrared or visible light.

Design study for a high reliability five-year spacecraft tape transport

NASA Technical Reports Server (NTRS)

Benn, G. S. L.; Eshleman, R. L.

1971-01-01

Following the establishment of the overall transport concept, a study of all of the life limiting constraints associated with the transport were analyzed using modeling techniques. These design techniques included: (1) a response analysis from which the performance of the transport could be determined under operating conditions for a variety of conceptual variations both in a new and aged condition; (2) an analysis of a double cone guidance technique which yielded an optimum design for maximum guidance with minimum tape degradation; (3) an analysis of the tape pack design to eliminate spoking caused by negative tangential stress within the pack; (4) an evaluation of the stress levels experienced by the magnetic tape throughout the system; (5) a general review of the bearing and lubrication technology as applied to satellite recorders and hence the recommendation for using standard load carrying antifriction ball bearings; and (6) a kinetic analysis to determine the change in kinetic properties of the transport during operation.

Method for experimental investigation of transient operation on Laval test stand for model size turbines

NASA Astrophysics Data System (ADS)

Fraser, R.; Coulaud, M.; Aeschlimann, V.; Lemay, J.; Deschenes, C.

2016-11-01

With the growing proportion of inconstant energy source as wind and solar, hydroelectricity becomes a first class source of peak energy in order to regularize the grid. The important increase of start - stop cycles may then cause a premature ageing of runners by both a higher number of cycles in stress fluctuations and by reaching a higher stress level in absolute. Aiming to sustain good quality development on fully homologous scale model turbines, the Hydraulic Machines Laboratory (LAMH) of Laval University has developed a methodology to operate model size turbines on transient regimes such as start-up, stop or load rejection on its test stand. This methodology allows maintaining a constant head while the wicket gates are opening or closing in a representative speed on the model scale of what is made on the prototype. This paper first presents the opening speed on model based on dimensionless numbers, the methodology itself and its application. Then both its limitation and the first results using a bulb turbine are detailed.

Hardiness as a predictor of mental health and well-being of Australian army reservists on and after stability operations.

PubMed

Orme, Geoffrey J; Kehoe, E James

2014-04-01

This study tested whether cognitive hardiness moderates the adverse effects of deployment-related stressors on health and well-being of soldiers on short-tour (4-7 months), peacekeeping operations. Australian Army reservists (N = 448) were surveyed at the start, end, and up to 24 months after serving as peacekeepers in Timor-Leste or the Solomon Islands. They retained sound mental health throughout (Kessler 10, Post-Traumatic Checklist-Civilian, Depression Anxiety Stress Scale 42). Ratings of either traumatic or nontraumatic stress were low. Despite range restrictions, scores on the Cognitive Hardiness Scale moderated the relationship between deployment stressors and a composite measure of psychological distress. Scatterplots revealed an asymmetric pattern for hardiness scores and measures of psychological distress. When hardiness scores were low, psychological distress scores were widely dispersed. However, when hardiness scores were higher, psychological distress scores became concentrated at a uniformly low level. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

Stress and Psychological Support in Modern Military Operations: A Military Leader’s Perspective

DTIC Science & Technology

2006-04-01

to let steam off and let the soldiers wind down after dealing with very risky situations. 5.0 MANAGEMENT OF STRESS DURING THE OPERATION ... Management of stress and the wellbeing of the soldiers in a unit is the ultimate responsibility of the Commanding Officer (CO): in turn the CO will rely on

Postdeployment resilience as a predictor of mental health in operation enduring freedom/operation iraqi freedom returnees.

PubMed

Eisen, Susan V; Schultz, Mark R; Glickman, Mark E; Vogt, Dawne; Martin, James A; Osei-Bonsu, Princess E; Drainoni, Mari-Lynn; Elwy, A Rani

2014-12-01

Much of the research on the impact of trauma exposure among veterans has focused on factors that increase risk for mental health problems. Fewer studies have investigated factors that may prevent mental health problems following trauma exposure. This study examines resilience variables as factors that may prevent subsequent mental health problems. To determine whether military service members returning from Afghanistan and Iraq who exhibit higher levels of resilience, including hardiness (encompassing control, commitment, and challenge), self-efficacy, and social support after returning from deployment are less vulnerable to subsequent mental health problems, alcohol, and drug use. A national sample of 512 service members was surveyed between 3 and 12 months of return from deployment and 6-12 months later. Data were collected in 2008-2009 and analyzed in 2013. Regression analyses ascertained whether resilience 3-12 months after return predicted later mental health and substance problems, controlling for demographic characteristics, mental health, and risk factors, including predeployment stressful events, combat exposure, and others. Greater hardiness predicted several indicators of better mental health and lower levels of alcohol use 6-12 months later, but did not predict subsequent posttraumatic stress symptom severity. Postdeployment social support predicted better overall mental health and less posttraumatic stress symptom severity, alcohol, and drug use. Some aspects of resilience after deployment appear to protect returning service members from the negative effects of traumatic exposure, suggesting that interventions to promote and sustain resilience after deployment have the potential to enhance the mental health of veterans. Copyright © 2014 American Journal of Preventive Medicine. All rights reserved.

Relationship between high on aspirin platelet reactivity and oxidative stress in coronary artery by-pass grafted patients.

PubMed

Kuliczkowski, Wiktor; Golanski, Ryszard; Bijak, Michal; Boryczka, Katarzyna; Kaczmarski, Jacek; Watala, Cezary; Golanski, Jacek

2016-03-01

The aim of the study was to assess the responsiveness of blood platelets to acetylsalicylic acid (ASA) in patients following coronary artery bypass grafting (CABG) surgery with relation to oxidative and antioxidative plasma status. The study included 37 patients treated with the CABG procedure. During the first 24 h after CABG patients were given 300 mg of ASA with the following dose of 150 mg daily. The blood was collected before the procedure and 10 days after. Whole blood platelet aggregation induced with arachidonic acid, collagen and adenosine diphosphate (ADP) was performed together with whole blood generation of thromboxane B2 (TxB2). Oxidative stress was measured before and 10 days after CABG with total oxidative plasma status (TOS) and total antioxidative status of the plasma (TAS). TOS/TAS index was calculated. We observed a significant increase in the TOS and TOS/TAS index and ADP-induced aggregation 10 days after CABG in comparison with its level before operation. There was a significant decrease in the arachidonic acid-induced aggregation and serum TxB2 level. Patients with ADP-induced and collagen-induced aggregation in the upper quartile had significantly higher TOS and TOS/TAS index before (ADP) and after the operation (ADP and collagen). There were 19 patients (51%) with high on aspirin platelet reactivity after CABG who had also higher TOS and TOS/TAS index and lower TAS value in comparison with aspirin responders. Despite ASA use, increased oxidative stress after CABG can overcome its antiplatelet effect and increase platelet activation through other pathways.

Deployment cycle stressors and post-traumatic stress symptoms in Army National Guard women: the mediating effect of resilience.

PubMed

Wooten, Nikki R

2012-01-01

This study examined the associations between deployment cycle stressors, post-traumatic stress symptoms (PTSS), and resilience in Army National Guard (ARNG) women deployed to Operations Enduring Freedom and Iraqi Freedom. Resilience was also tested as a mediator. Hierarchical linear regression indicated that deployment and post-deployment stressors were positively associated, and resilience was negatively associated with PTSS. Resilience fully mediated the association between post-deployment stressors and PTSS. Findings suggest assessing deployment and post-deployment stressors in ARNG women may be helpful in identifying those at risk for severe PTSS; and highlight the potential of individual-level resilient characteristics in mitigating the adverse impact of post-deployment stressors.

Protection of Electrical Systems from EM Hazards - Design Guide.

DTIC Science & Technology

1981-09-01

cm) Surface flashover Voltage (KV/cm) This criterion should be met for lighting voltage stresses of either polarity applied at up to 1000 KV/v sec rate...suppressor devices can be predicted. The part failure rate models in the handbook include the effects of part electrical stress , thermal stress , operating... stress . This test series contained over one million device hours of operation at temperatures uF to 145°C. The average duration of testing ranges from

Three Year Aging of Prototype Flight Laser at 10 Khz and 1 Ns Pulses with External Frequency Doubler for the Icesat-2 Mission

NASA Technical Reports Server (NTRS)

Konoplev, Oleg A.; Chiragh, Furqan L.; Vasilyev, Aleksey A.; Edwards, Ryan; Stephen, Mark A.; Troupaki, Elisavet; Yu, Anthony W.; Krainak, Michael A.; Sawruk, Nick; Hovis, Floyd;

Three Three-Year Aging of Prototype Flight Laser at 10 kHz and 1 ns Pulses With External Frequency Doubler for ICESat-2 Mission

NASA Technical Reports Server (NTRS)

Konoplev, Oleg A.; Chiragh, Furqan L.; Vasilyev, Aleksey A.; Edwards, Ryan; Stephen, Mark A.; Troupaki, Elisavet; Yu, Anthony W.; Krainak, Michael A.; Sawruk, Nick; Hovis, Floyd;

A novel attention training paradigm based on operant conditioning of eye gaze: Preliminary findings.

PubMed

Price, Rebecca B; Greven, Inez M; Siegle, Greg J; Koster, Ernst H W; De Raedt, Rudi

2016-02-01

Inability to engage with positive stimuli is a widespread problem associated with negative mood states across many conditions, from low self-esteem to anhedonic depression. Though attention retraining procedures have shown promise as interventions in some clinical populations, novel procedures may be necessary to reliably attenuate chronic negative mood in refractory clinical populations (e.g., clinical depression) through, for example, more active, adaptive learning processes. In addition, a focus on individual difference variables predicting intervention outcome may improve the ability to provide such targeted interventions efficiently. To provide preliminary proof-of-principle, we tested a novel paradigm using operant conditioning to train eye gaze patterns toward happy faces. Thirty-two healthy undergraduates were randomized to receive operant conditioning of eye gaze toward happy faces (train-happy) or neutral faces (train-neutral). At the group level, the train-happy condition attenuated sad mood increases following a stressful task, in comparison to train-neutral. In individual differences analysis, greater physiological reactivity (pupil dilation) in response to happy faces (during an emotional face-search task at baseline) predicted decreased mood reactivity after stress. These Preliminary results suggest that operant conditioning of eye gaze toward happy faces buffers against stress-induced effects on mood, particularly in individuals who show sufficient baseline neural engagement with happy faces. Eye gaze patterns to emotional face arrays may have a causal relationship with mood reactivity. Personalized medicine research in depression may benefit from novel cognitive training paradigms that shape eye gaze patterns through feedback. Baseline neural function (pupil dilation) may be a key mechanism, aiding in iterative refinement of this approach. (c) 2016 APA, all rights reserved).

Oxidative lung injury correlates with one-lung ventilation time during pulmonary lobectomy: a study of exhaled breath condensate and blood.

PubMed

García-de-la-Asunción, José; García-del-Olmo, Eva; Perez-Griera, Jaume; Martí, Francisco; Galan, Genaro; Morcillo, Alfonso; Wins, Richard; Guijarro, Ricardo; Arnau, Antonio; Sarriá, Benjamín; García-Raimundo, Miguel; Belda, Javier

2015-09-01

During lung lobectomy, the operated lung is collapsed and hypoperfused; oxygen deprivation is accompanied by reactive hypoxic pulmonary vasoconstriction. After lung lobectomy, ischaemia present in the collapsed state is followed by expansion-reperfusion and lung injury attributed to the production of reactive oxygen species. The primary objective of this study was to investigate the time course of several markers of oxidative stress simultaneously in exhaled breath condensate and blood and to determine the relationship between oxidative stress and one-lung ventilation time in patients undergoing lung lobectomy. This single-centre, observational, prospective study included 28 patients with non-small-cell lung cancer who underwent lung lobectomy. We measured the levels of hydrogen peroxide, 8-iso-PGF2α, nitrites plus nitrates and pH in exhaled breath condensate (n = 25). The levels of 8-iso-PGF2α and nitrites plus nitrates were also measured in blood (n = 28). Blood samples and exhaled breath condensate samples were collected from all patients at five time points: preoperatively; during one-lung ventilation, immediately before resuming two-lung ventilation; immediately after resuming two-lung ventilation; 60 min after resuming two-lung ventilation and 180 min after resuming two-lung ventilation. Both exhaled breath condensate and blood exhibited significant and simultaneous increases in oxidative-stress markers immediately before two-lung ventilation was resumed. However, all these values underwent larger increases immediately after resuming two-lung ventilation. In both exhaled breath condensate and blood, marker levels significantly and directly correlated with the duration of one-lung ventilation immediately before resuming two-lung ventilation and immediately after resuming two-lung ventilation. Although pH significantly decreased in exhaled breath condensate immediately after resuming two-lung ventilation, these pH values were inversely correlated with the duration of one-lung ventilation. During lung lobectomy, the operated lung is collapsed and oxidative injury occurs, with the levels of markers of oxidative stress increasing simultaneously in exhaled breath condensate and blood during one-lung ventilation. These increases were larger after resuming two-lung ventilation. Increases immediately before resuming two-lung ventilation and immediately after resuming two-lung ventilation were directly correlated with the duration of one-lung ventilation. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Advanced gearbox technology

NASA Technical Reports Server (NTRS)

Anderson, N. E.; Cedoz, R. W.; Salama, E. E.; Wagner, D. A.

1987-01-01

An advanced 13,000 HP, counterrotating (CR) gearbox was designed and successfully tested to provide a technology base for future designs of geared propfan propulsion systems for both commercial and military aircraft. The advanced technology CR gearbox was designed for high efficiency, low weight, long life, and improved maintainability. The differential planetary CR gearbox features double helical gears, double row cylindrical roller bearings integral with planet gears, tapered roller prop support bearings, and a flexible ring gear and diaphragm to provide load sharing. A new Allison propfan back-to-back gearbox test facility was constructed. Extensive rotating and stationary instrumentation was used to measure temperature, strain, vibration, deflection and efficiency under representative flight operating conditions. The tests verified smooth, efficient gearbox operation. The highly-instrumented advanced CR gearbox was successfully tested to design speed and power (13,000 HP), and to a 115 percent overspeed condition. Measured CR gearbox efficiency was 99.3 percent at the design point based on heat loss to the oil. Tests demonstrated low vibration characteristics of double helical gearing, proper gear tooth load sharing, low stress levels, and the high load capacity of the prop tapered roller bearings. Applied external prop loads did not significantly affect gearbox temperature, vibration, or stress levels. Gearbox hardware was in excellent condition after the tests with no indication of distress.

Intensification of anxiety and depression, and personal resources among women during the peri-operative period.

PubMed

Lewicka, Magdalena; Makara-Studzińska, Marta; Sulima, Magdalena; Wiktor, Henryk

2014-01-01

Surgical treatment of women due to gynaecological disorders is the cause of stress and may lead to psychological changes. Studies concerning human response to stress emphasize the importance of the effect of the level of the sense of coherence, anxiety, depression, dispositional optimism and skills of expressing emotions on the quality of feelings and experiences in difficult situations. The study covered 232 women who had undergone gynaecological surgery due to various causes. Permission to conduct the research was obtained from the Bioethical Commission at the Medical University in Lublin. The study was carried out with the use of the State-Trait Anxiety Inventory (STAI), the Beck Depression Inventory, Courtauld Emotional Control Scale (CECS), and Life Orientation Test - Revised (LOT-R). The study showed that investigations of the sense of coherence, level of anxiety and depression, and personal resources allow determination of the characteristics of patients who should be covered with special psycho-prophylactic care during the peri-operative period. In addition, the results of own studies obtained may be used for the development of adequate principles of psycho-prophylactic management in the course of the diagnostic-treatment process with respect to women who had undergone surgical treatment due to gynaecological disorders.

The Epidemiology of Operation Stress during Continuing Promise 2011: A Humanitarian Response and Disaster Relief Mission aboard a US Navy Hospital Ship.

PubMed

Scouten, William T; Mehalick, Melissa L; Yoder, Elizabeth; McCoy, Andrea; Brannock, Tracy; Riddle, Mark S

2017-08-01

Introduction Operational stress describes individual behavior in response to the occupational demands and tempo of a mission. The stress response of military personnel involved in combat and peace-keeping missions has been well-described. The spectrum of effect on medical professionals and support staff providing humanitarian assistance, however, is less well delineated. Research to date concentrates mainly on shore-based humanitarian missions. Problem The goal of the current study was to document the pattern of operational stress, describe factors responsible for it, and the extent to which these factors impact job performance in military and civilian participants of Continuing Promise 2011 (CP11), a ship-based humanitarian medical mission. This was a retrospective study of Disease Non-Battle Injury (DNBI) data from the medical sick-call clinic and from weekly self-report questionnaires for approximately 900 US military and civilian mission participants aboard the USNS COMFORT (T-AH 20). The incidence rates and job performance impact of reported Operational Stress/Mental Health (OS/MH) issues and predictors (age, rank, occupation, service branch) of OS/MH issues (depression, anxiety) were analyzed over a 22-week deployment period. Incidence rates of OS/MH complaints from the sick-call clinic were 3.7% (4.5/1,000 persons) and 12.0% (53/1,000 persons) from the self-report questionnaire. The rate of operational stress increased as the mission progressed and fluctuated during the mission according to ship movement. Approximately 57% of the responders reported no impact on job performance. Younger individuals (enlisted ranks E4-6, officer ranks O1-3), especially Air Force service members, those who had spent only one day off ship, and those who were members of specific directorates, reported the highest rates of operational stress. The overall incidence of OS/MH complaints was low in participants of CP11 but was under-estimated by clinic-based reporting. The OS/MH complaints increased as the mission progressed, were more prevalent in certain groups, and appeared to be related to ship's movement. These findings document the pattern of operational stress in a ship-based medical humanitarian mission and confirm unique ship-based stressors. This information may be used by planners of similar missions to develop mitigation strategies for known stressors and by preventive medicine, behavioral health specialists, and mission leaders to develop sensitive surveillance tools to better detect and manage operational stress while on mission. Scouten WT , Mehalick ML , Yoder E , McCoy A , Brannock T , Riddle MS . The epidemiology of operation stress during Continuing Promise 2011: a humanitarian response and disaster relief mission aboard a US Navy hospital ship. Prehosp Disaster Med. 2017;32(4):393-402.

Negative-pressure-induced enhancement in a freestanding ferroelectric

NASA Astrophysics Data System (ADS)

Wang, Jin; Wylie-van Eerd, Ben; Sluka, Tomas; Sandu, Cosmin; Cantoni, Marco; Wei, Xian-Kui; Kvasov, Alexander; McGilly, Leo John; Gemeiner, Pascale; Dkhil, Brahim; Tagantsev, Alexander; Trodahl, Joe; Setter, Nava

2015-10-01

Ferroelectrics are widespread in technology, being used in electronics and communications, medical diagnostics and industrial automation. However, extension of their operational temperature range and useful properties is desired. Recent developments have exploited ultrathin epitaxial films on lattice-mismatched substrates, imposing tensile or compressive biaxial strain, to enhance ferroelectric properties. Much larger hydrostatic compression can be achieved by diamond anvil cells, but hydrostatic tensile stress is regarded as unachievable. Theory and ab initio treatments predict enhanced properties for perovskite ferroelectrics under hydrostatic tensile stress. Here we report negative-pressure-driven enhancement of the tetragonality, Curie temperature and spontaneous polarization in freestanding PbTiO3 nanowires, driven by stress that develops during transformation of the material from a lower-density crystal structure to the perovskite phase. This study suggests a simple route to obtain negative pressure in other materials, potentially extending their exploitable properties beyond their present levels.

Shape optimization of disc-type flywheels

NASA Technical Reports Server (NTRS)

Nizza, R. S.

1976-01-01

Techniques were developed for presenting an analytical and graphical means for selecting an optimum flywheel system design, based on system requirements, geometric constraints, and weight limitations. The techniques for creating an analytical solution are formulated from energy and structural principals. The resulting flywheel design relates stress and strain pattern distribution, operating speeds, geometry, and specific energy levels. The design techniques incorporate the lowest stressed flywheel for any particular application and achieve the highest specific energy per unit flywheel weight possible. Stress and strain contour mapping and sectional profile plotting reflect the results of the structural behavior manifested under rotating conditions. This approach toward flywheel design is applicable to any metal flywheel, and permits the selection of the flywheel design to be based solely on the criteria of the system requirements that must be met, those that must be optimized, and those system parameters that may be permitted to vary.

Enabling reliability assessments of pre-commercial perovskite photovoltaics with lessons learned from industrial standards

NASA Astrophysics Data System (ADS)

Snaith, Henry J.; Hacke, Peter

2018-06-01

Photovoltaic modules are expected to operate in the field for more than 25 years, so reliability assessment is critical for the commercialization of new photovoltaic technologies. In early development stages, understanding and addressing the device degradation mechanisms are the priorities. However, any technology targeting large-scale deployment must eventually pass industry-standard qualification tests and undergo reliability testing to validate the module lifetime. In this Perspective, we review the methodologies used to assess the reliability of established photovoltaics technologies and to develop standardized qualification tests. We present the stress factors and stress levels for degradation mechanisms currently identified in pre-commercial perovskite devices, along with engineering concepts for mitigation of those degradation modes. Recommendations for complete and transparent reporting of stability tests are given, to facilitate future inter-laboratory comparisons and to further the understanding of field-relevant degradation mechanisms, which will benefit the development of accelerated stress tests.

The visual stress model—A psycho-physiological method for the evaluation of operational reliability of pilots and cosmonauts

NASA Astrophysics Data System (ADS)

Kammel, H.; Haase, H.

An experimental psycho-physiological method is presented for the evaluation of visual-cognitive performance preconditions and operational reliability of pilots and cosmonauts. As visual-cognitive stress are used tachistoscopically presented instrument symbols under conditions of individual speed of work and time pressure. The results of the compared extreme groups consisting of pilots with good and insufficient flight performance showed that the pilots with impairments to the quality of flight activity differ already before the test in their individual habitual characteristics and actual motivation, during the stress in their operational parameters, in the dimensions of their cardiorespiratory activation as well as in their efficiency and after the stress in their subjective experience of the stress. Conclusions are drawn for the evaluation of the aptitude of pilots and cosmonauts.

Approach to Operational Experimental Estimation of Static Stresses of Elements of Mechanical Structures

NASA Astrophysics Data System (ADS)

Sedov, A. V.; Kalinchuk, V. V.; Bocharova, O. V.

2018-01-01

The evaluation of static stresses and strength of units and components is a crucial task for increasing reliability in the operation of vehicles and equipment, to prevent emergencies, especially in structures made of metal and composite materials. At the stage of creation and commissioning of structures to control the quality of manufacturing of individual elements and components, diagnostic control methods are widely used. They are acoustic, ultrasonic, X-ray, radiation methods and others. The using of these methods to control the residual life and the degree of static stresses of units and parts during operation is fraught with great difficulties both in methodology and in instrumentation. In this paper, the authors propose an effective approach of operative control of the degree of static stresses of units and parts of mechanical structures which are in working condition, based on recording the changing in the surface wave properties of a system consisting of a sensor and a controlled environment (unit, part). The proposed approach of low-frequency diagnostics of static stresses presupposes a new adaptive-spectral analysis of a surface wave created by external action (impact). It is possible to estimate implicit stresses of structures in the experiment due to this approach.

Physical controls and depth of emplacement of igneous bodies: A review

NASA Astrophysics Data System (ADS)

Menand, Thierry

2011-03-01

The formation and growth of magma bodies are now recognised as involving the amalgamation of successive, discrete pulses such as sills. Sills would thus represent the building blocks of larger plutons ( sensu lato). Mechanical and thermal considerations on the incremental development of these plutons raise the issue of the crustal levels at which magma can stall and accumulate as sills. Reviewing the mechanisms that could a priori explain sill formation, it is shown that principal physical controls include: rigidity contrast, where sills form at the interface between soft strata overlaid by comparatively stiffer strata; rheology anisotropy, where sills form within the weakest ductile zones; and rotation of deviatoric stress, where sills form when the minimum compressive stress becomes vertical. Comparatively, the concept of neutral buoyancy is unlikely to play a leading control in the emplacement of sills, although it could assist their formation. These different controls on sill formation, however, do not necessarily operate on the same length scale. The length scale associated with the presence of interfaces separating upper stiffer layers from lower softer ones determines the depth at which rigidity-controlled sills will form. On another hand, the emplacement depths for rheology-controlled sills are likely to be determined by the distribution of the weakest ductile zones. Whereas the emplacement depth of stress-controlled sills is determined by a balance between the horizontal maximum compressive stress, which favours sill formation, and the buoyancy of their feeder dykes, which drives magma vertically. Ultimately, the depth at which a sill forms depends on whether crustal anisotropy or stress rotation is the dominant control, i.e. which of these processes operates at the smallest length scale. Using dimensional analysis, it is shown that sill formation controlled by remote stress rotation would occur on length scales of hundreds of meters or greater. This therefore suggests that crustal heterogeneities and their associated anisotropy are likely to play a larger role than remote stress rotation in controlling sill emplacement, unless these heterogeneities are several hundred meters or more apart. This also reinforces the role of local stress barriers, owing to interactions between deviatoric stress and crustal heterogeneities, in the formation of sills.

Coupled Mechanical and Electrochemical Phenomena in Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Cannarella, John

Lithium-ion batteries are complee electro-chemo-mechanical systems owing to a number of coupled mechanical and electrochemical phenomena that occur during operation. In this thesis we explore these phenomena in the context of battery degradation, monitoring/diagnostics, and their application to novel energy systems. We begin by establishing the importance of bulk stress in lithium-ion batteries through the presentation of a two-year exploratory aging study which shows that bulk mechanical stress can significantly accelerate capacity fade. We then investigate the origins of this coupling between stress and performance by investigating the effects of stress in idealized systems. Mechanical stress is found to increase internal battery resistance through separator deformation, which we model by considering how deformation affects certain transport properties. When this deformation occurs in a spatially heterogeneous manner, local hot spots form, which accelerate aging and in some cases lead to local lithium plating. Because of the importance of separator deformation with respect to mechanically-coupled aging, we characterize the mechanical properties of battery separators in detail. We also demonstrate that the stress state of a lithium-ion battery cell can be used to measure the cell's state of health (SOH) and state of charge (SOC)--important operating parameters that are traditionally difficult to measure outside of a laboratory setting. The SOH is shown to be related to irreversible expansion that occurs with degradation and the SOC to the reversible strains characteristic of the cell's electrode materials. The expansion characteristics and mechanical properties of the constituent cell materials are characterized, and a phenomenological model for the relationship between stress and SOH/SOC is developed. This work forms the basis for the development of on-board monitoring of SOH/SOC based on mechanical measurements. Finally we study the coupling between mechanical stress and voltage in lithium-ion batteries. While the voltage changes at typical levels of stress are relatively insignificant from the standpoint of battery performance, we show that this piezoelectrochemical phenomenon is well-suited for certain mechanical energy harvesting applications. We demonstrate the working principle for mechanical energy harvesting and explore the potential of this technology.

Testosterone Deficiency Causes Endothelial Dysfunction via Elevation of Asymmetric Dimethylarginine and Oxidative Stress in Castrated Rats.

PubMed

Kataoka, Tomoya; Hotta, Yuji; Maeda, Yasuhiro; Kimura, Kazunori

2017-12-01

Testosterone is believed to mediate the penile erectile response by producing adequate nitric oxide; therefore, testosterone deficiency results in erectile dysfunction through decreased nitric oxide bioavailability. However, the mechanisms underlying endothelial dysfunction in testosterone deficiency remain unclear. To investigate the mechanism of endothelial dysfunction in a rat model of testosterone deficiency. Rats were distributed into 3 groups: castrated (Cast), castrated and supplemented with testosterone (Cast + T), and sham (Sham). In the Cast + T group, castrated rats were treated daily with subcutaneous testosterone (3 mg/kg daily) for 4 weeks; Sham and Cast rats received only the vehicle. Erectile function using intracavernosal pressure and mean arterial pressure measurements after electrical stimulation of the cavernous nerve, endothelial function using isometric tension, asymmetric dimethylarginine (ADMA) levels using ultra-performance liquid chromatography and tandem mass spectrometry, and inflammatory biomarker expression were performed 4 weeks after the operation. In the Cast group, the ratio of intracavernosal pressure to mean arterial pressure significantly decreased, acetylcholine-induced relaxation was lower, and serum ADMA, oxidative stress, and inflammation biomarker levels were significantly increased (P < .01). Testosterone injection significantly improved each of these parameters (P < .01). The present results provide scientific evidence of the effect of testosterone deficiency on erectile function and the effect of testosterone replacement therapy. This study provides evidence of the influence of testosterone deficiency on endothelial function by investigating ADMA and oxidative stress. A major limitation of this study is the lack of a direct link of increased ADMA by oxidative stress to inflammation. Testosterone deficiency increased not only ADMA levels but also oxidative stress and inflammation in castrated rats, which can cause damage to the corpus cavernosum, resulting in erectile dysfunction. Kataoka T, Hotta Y, Maeda Y, Kimura K. Testosterone Deficiency Causes Endothelial Dysfunction via Elevation of Asymmetric Dimethylarginine and Oxidative Stress in Castrated Rats. J Sex Med 2017;14:1540-1548. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Working-memory capacity protects model-based learning from stress.

PubMed

Otto, A Ross; Raio, Candace M; Chiang, Alice; Phelps, Elizabeth A; Daw, Nathaniel D

2013-12-24

Accounts of decision-making have long posited the operation of separate, competing valuation systems in the control of choice behavior. Recent theoretical and experimental advances suggest that this classic distinction between habitual and goal-directed (or more generally, automatic and controlled) choice may arise from two computational strategies for reinforcement learning, called model-free and model-based learning. Popular neurocomputational accounts of reward processing emphasize the involvement of the dopaminergic system in model-free learning and prefrontal, central executive-dependent control systems in model-based choice. Here we hypothesized that the hypothalamic-pituitary-adrenal (HPA) axis stress response--believed to have detrimental effects on prefrontal cortex function--should selectively attenuate model-based contributions to behavior. To test this, we paired an acute stressor with a sequential decision-making task that affords distinguishing the relative contributions of the two learning strategies. We assessed baseline working-memory (WM) capacity and used salivary cortisol levels to measure HPA axis stress response. We found that stress response attenuates the contribution of model-based, but not model-free, contributions to behavior. Moreover, stress-induced behavioral changes were modulated by individual WM capacity, such that low-WM-capacity individuals were more susceptible to detrimental stress effects than high-WM-capacity individuals. These results enrich existing accounts of the interplay between acute stress, working memory, and prefrontal function and suggest that executive function may be protective against the deleterious effects of acute stress.

Working-memory capacity protects model-based learning from stress

PubMed Central

Otto, A. Ross; Raio, Candace M.; Chiang, Alice; Phelps, Elizabeth A.; Daw, Nathaniel D.

2013-01-01

Accounts of decision-making have long posited the operation of separate, competing valuation systems in the control of choice behavior. Recent theoretical and experimental advances suggest that this classic distinction between habitual and goal-directed (or more generally, automatic and controlled) choice may arise from two computational strategies for reinforcement learning, called model-free and model-based learning. Popular neurocomputational accounts of reward processing emphasize the involvement of the dopaminergic system in model-free learning and prefrontal, central executive–dependent control systems in model-based choice. Here we hypothesized that the hypothalamic-pituitary-adrenal (HPA) axis stress response—believed to have detrimental effects on prefrontal cortex function—should selectively attenuate model-based contributions to behavior. To test this, we paired an acute stressor with a sequential decision-making task that affords distinguishing the relative contributions of the two learning strategies. We assessed baseline working-memory (WM) capacity and used salivary cortisol levels to measure HPA axis stress response. We found that stress response attenuates the contribution of model-based, but not model-free, contributions to behavior. Moreover, stress-induced behavioral changes were modulated by individual WM capacity, such that low-WM-capacity individuals were more susceptible to detrimental stress effects than high-WM-capacity individuals. These results enrich existing accounts of the interplay between acute stress, working memory, and prefrontal function and suggest that executive function may be protective against the deleterious effects of acute stress. PMID:24324166

Long-Term Stability of Residual Stress Improvement by Water Jet Peening Considering Working Processes.

PubMed

Hashimoto, Tadafumi; Osawa, Yusuke; Itoh, Shinsuke; Mochizuki, Masahito; Nishimoto, Kazutoshi

2013-06-01

To prevent primary water stress corrosion cracking (PWSCC), water jet peening (WJP) has been used on the welds of Ni-based alloys in pressurized water reactors (PWRs). Before WJP, the welds are machined and buffed in order to conduct a penetrant test (PT) to verify the weld qualities to access, and microstructure evolution takes place in the target area due to the severe plastic deformation. The compressive residual stresses induced by WJP might be unstable under elevated temperatures because of the high dislocation density in the compressive stress layer. Therefore, the stability of the compressive residual stresses caused by WJP was investigated during long-term operation by considering the microstructure evolution due to the working processes. The following conclusions were made: The compressive residual stresses were slightly relaxed in the surface layers of the thermally aged specimens. There were no differences in the magnitude of the relaxation based on temperature or time. The compressive residual stresses induced by WJP were confirmed to remain stable under elevated temperatures. The stress relaxation at the surface followed the Johnson-Mehl equation, which states that stress relaxation can occur due to the recovery of severe plastic strain, since the estimated activation energy agrees very well with the self-diffusion energy for Ni. By utilizing the additivity rule, it was indicated that stress relaxation due to recovery is completed during the startup process. It was proposed that the long-term stability of WJP under elevated temperatures must be assessed based on compressive stresses with respect to the yield stress. Thermal elastic-plastic creep analysis was performed to predict the effect of creep strain. After 100 yr of simulated continuous operation at 80% capacity, there was little change in the WJP compressive stresses under an actual operating temperature of 623 K. Therefore, the long-term stability of WJP during actual operation was analytically predicted.

Slug Test Characterization Results for Multi-Test/Depth Intervals Conducted During the Drilling of CERCLA Operable Unit OU ZP-1 Wells 299-W10-33 and 299-W11-48

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

Newcomer, Darrell R.

2007-09-30

Slug-test results obtained from single and multiple, stress-level slug tests conducted during drilling and borehole advancement provide detailed hydraulic conductivity information at two Hanford Site Operable Unit (OU) ZP-1 test well locations. The individual test/depth intervals were generally sited to provide hydraulic-property information within the upper ~10 m of the unconfined aquifer (i.e., Ringold Formation, Unit 5). These characterization results complement previous and ongoing drill-and-test characterization programs at surrounding 200-West and -East Area locations (see Figure S.1).

Eddy current spectroscopy for near-surface residual stress profiling in surface treated nonmagnetic engine alloys

NASA Astrophysics Data System (ADS)

Abu-Nabah, Bassam A.

Recent research results indicated that eddy current conductivity measurements can be exploited for nondestructive evaluation of near-surface residual stresses in surface-treated nickel-base superalloy components. Most of the previous experimental studies were conducted on highly peened (Almen 10-16A) specimens that exhibit harmful cold work in excess of 30% plastic strain. Such high level of cold work causes thermo-mechanical relaxation at relatively modest operational temperatures; therefore the obtained results were not directly relevant to engine manufacturers and end users. The main reason for choosing peening intensities in excess of recommended normal levels was that in low-conductivity engine alloys the eddy current penetration depth could not be forced below 0.2 mm without expanding the measurements above 10 MHz which is beyond the operational range of most commercial eddy current instruments. As for shot-peened components, it was initially felt that the residual stress effect was more difficult to separate from cold work, texture, and inhomogeneity effects in titanium alloys than in nickel-base superalloys. In addition, titanium alloys have almost 50% lower electric conductivity than nickel-base superalloys; therefore require proportionally higher inspection frequencies, which was not feasible until our recent breakthrough in instrument development. Our work has been focused on six main aspects of this continuing research, namely, (i) the development of an iterative inversion technique to better retrieve the depth-dependent conductivity profile from the measured frequency-dependent apparent eddy current conductivity (AECC), (ii) the extension of the frequency range up to 80 MHz to better capture the peak compressive residual stress in nickel-base superalloys using a new eddy current conductivity measuring system, which offers better reproducibility, accuracy and measurement speed than the previously used conventional systems, (iii) the lift-off effect on high frequency eddy current spectroscopy, (iv) the development of custom-made spiral coils to allow eddy current conductivity characterization over the whole frequency range of interest with reduced coil sensitivity to lift off, (v) the benefits of implementing a semi-quadratic system calibration in reducing the coil sensitivity to lift-off, and (vi) the feasibility of adapting high-frequency eddy current residual stress characterization for shot-peened titanium alloys.

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

Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul, E-mail: rahul@iitmandi.ac.in

With the advent of modern power electronics, embedded circuits and non-conventional energy harvesting, the need for high performance capacitors is bound to become indispensible. The current state-of-art employs ferroelectric ceramics and linear dielectrics for solid state capacitance. However, lead-free ferroelectric ceramics propose to offer significant improvement in the field of electrical energy storage owing to their high discharge efficiency and energy storage density. In this regards, the authors have investigated the effects of compressive stress as a means of improving the energy storage density of lead-free ferroelectric ceramics. The energy storage density of 0.91(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.07BaTiO{sub 3}-0.02(K{sub 0.5}Na{sub 0.5})NbO{submore » 3} ferroelectric bulk ceramic was analyzed as a function of varying levels of compressive stress and operational temperature .It was observed that a peak energy density of 387 mJ.cm{sup -3} was obtained at 100 MPa applied stress (25{sup o}C). While a maximum energy density of 568 mJ.cm{sup -3} was obtained for the same stress at 80{sup o}C. These values are indicative of a significant, 25% and 84%, improvement in the value of stored energy compared to an unloaded material. Additionally, material's discharge efficiency has also been discussed as a function of operational parameters. The observed phenomenon has been explained on the basis of field induced structural transition and competitive domain switching theory.« less

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

PubMed

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

2006-11-01

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

The position of a standard optical computer mouse affects cardiorespiratory responses during the operation of a computer under time constraints.

PubMed

Sako, Shunji; Sugiura, Hiromichi; Tanoue, Hironori; Kojima, Makoto; Kono, Mitsunobu; Inaba, Ryoichi

2014-08-01

This study investigated the association between task-induced stress and fatigue by examining the cardiovascular responses of subjects using different mouse positions while operating a computer under time constraints. The study was participated by 16 young, healthy men and examined the use of optical mouse devices affixed to laptop computers. Two mouse positions were investigated: (1) the distal position (DP), in which the subjects place their forearms on the desk accompanied by the abduction and flexion of their shoulder joints, and (2) the proximal position (PP), in which the subjects place only their wrists on the desk without using an armrest. The subjects continued each task for 16 min. We assessed differences in several characteristics according to mouse position, including expired gas values, autonomic nerve activities (based on cardiorespiratory responses), operating efficiencies (based on word counts), and fatigue levels (based on the visual analog scale - VAS). Oxygen consumption (VO(2)), the ratio of inspiration time to respiration time (T(i)/T(total)), respiratory rate (RR), minute ventilation (VE), and the ratio of expiration to inspiration (Te/T(i)) were significantly lower when the participants were performing the task in the DP than those obtained in the PP. Tidal volume (VT), carbon dioxide output rates (VCO(2)/VE), and oxygen extraction fractions (VO(2)/VE) were significantly higher for the DP than they were for the PP. No significant difference in VAS was observed between the positions; however, as the task progressed, autonomic nerve activities were lower and operating efficiencies were significantly higher for the DP than they were for the PP. Our results suggest that the DP has fewer effects on cardiorespiratory functions, causes lower levels of sympathetic nerve activity and mental stress, and produces a higher total workload than the PP. This suggests that the DP is preferable to the PP when operating a computer.

Inhibiting the Physiological Stress Effects of a Sustained Attention Task on Shoulder Muscle Activity.

PubMed

Wixted, Fiona; O'Riordan, Cliona; O'Sullivan, Leonard

2018-01-11

The objective of this study was to investigate if a breathing technique could counteract the effects of hyperventilation due to a sustained attention task on shoulder muscle activity. The trend towards higher levels of automation in industry is increasing. Consequently, manufacturing operators often monitor automated process for long periods of their work shift. Prolonged monitoring work requires sustained attention, which is a cognitive process that humans are typically poor at and find stressful. As sustained attention becomes an increasing requirement of manufacturing operators' job content, the resulting stress experienced could contribute to the onset of many health problems, including work related musculoskeletal disorders (WRMSDs). The SART attention test was completed by a group of participants before and after a breathing intervention exercise. The effects of the abdominal breathing intervention on breathing rate, upper trapezius muscle activity and end-tidal CO₂ were evaluated. The breathing intervention reduced the moderation effect of end-tidal CO₂ on upper trapezius muscle activity. Abdominal breathing could be a useful technique in reducing the effects of sustained attention work on muscular activity. This research can be applied to highly-automated manufacturing industries, where prolonged monitoring of work is widespread and could, in its role as a stressor, be a potential contributor to WRMSDs.

Relationship between self-reported mental stressors at the workplace and salivary cortisol.

PubMed

Maina, Giovanni; Palmas, Antonio; Filon, Francesca Larese

2008-02-01

To investigate the association between work stress measures and salivary cortisol excretion in working and weekend days. In a sample of 68 healthy young call-centre operators dimensions of job stress from the demand-control model were related to repeated measures of salivary cortisol on seven samples (at awakening, +30 min, +60 min, + 3 h, +6 h, +9 h, and +12 h after awakening) at two working days and a weekend day. The cortisol excretion on work days was higher than during weekend day with gender-specific differences as women only showed higher significant values for area under the curve (AUC(G)) and Diurnal cycle (chi(2) (2) = 8.10, P < 0.05; chi(2) (2) = 15.75, P < 0.05, respectively). There were no associations between job demand, job control and cortisol excretion, while the sociodemographic characteristics of the call-centre operators showed linear relation with the diurnal pattern of cortisol secretory activity. The hypothalamic-pituitary adrenocortical axis activation was higher in working day than in weekend day. This activation measured by salivary cortisol was not related to self-reported mental stressors assessed with job strain model. The availability of more specific psychometric scales would be useful to explore the relationship between salivary cortisol levels and measures of mental stress at workplace.

Anxiety and perceived psychological stress play an important role in the immune response after exercise.

PubMed

Edwards, Jason P; Walsh, Neil P; Diment, Philip C; Roberts, Ross

2018-01-01

There are common pathways by which psychological stress and exercise stress alter immunity. However, it remains unknown whether psychological stress plays a role in the in vivo immune response to exercise. We examined the relationship between anxiety and perceived psychological stress reported before exercise and in vivo immunity after exercise using skin sensitisation with Diphenylcyclopropenone (DPCP). In a randomised design, sixty four, thoroughly familiarised, males completed widely used psychological instruments to assess state-anxiety and perceived psychological stress before exercise, and ran either 30 minutes at 60% (30MI) or 80% (30HI) V . O2peak, 120 minutes at 60% (120MI) V . O2peak or rested (CON) before DPCP sensitisation. Cutaneous recall to DPCP was measured as the dermal thickening response to a low-dose series DPCP challenge 4-weeks after sensitisation. After accounting for exercise (R2 = 0.20; P < 0.01), multiple-regression showed that pre-exercise state-anxiety (STAI-S; ΔR2 = 0.19; P < 0.01) and perceived psychological stress (ΔR2 = 0.13; P < 0.05) were moderately associated with the DPCP response after exercise. The STAI-S scores before exercise were considered low-to-moderate in these familiarised individuals (median split; mean STAI-S of low 25 and moderate 34). Further examination showed that the DPCP response after exercise (30MI, 30HI or 120MI) was 62% lower in those reporting low vs. moderate state-anxiety before exercise (mean difference in dermal thickening: -2.6 mm; 95% CI: -0.8 to -4.4 mm; P < 0.01). As such, the results indicate a beneficial effect of moderate (vs. low) state-anxiety and perceived psychological stress on in vivo immunity after exercise. Moreover, correlations were of comparable strength for the relationship between physiological stress (heart rate training impulse) and the summed dermal response to DPCP (r = -0.37; 95% CI: -0.05 to -0.62; P = 0.01), and state-anxiety and the summed dermal response to DPCP (r = 0.39; 95% CI: 0.08 to 0.63; P < 0.01). In conclusion, state-anxiety and perceived psychological stress levels before exercise play animportant role in determining the strength of the in vivo immune response after exercise. These findings indicate a similar strength relationship for the level of state-anxiety prior to exercise and the level of physiological stress during exercise with the in vivo immune response after exercise. Future research is required to investigate exercise-immune responses in athletes, military personnel and others in physically demanding occupations experiencing higher levels of psychological stress than those reported in this study e.g. related to important competition, military operations and major life events. Nevertheless, the present findings support the recommendation that exercise scientists should account for anxiety and psychological stress when examining the immune response to exercise. Copyright © 2016 International Society of Exercise and Immunology. All rights reserved.

Honokiol protects against renal ischemia/reperfusion injury via the suppression of oxidative stress, iNOS, inflammation and STAT3 in rats.

PubMed

Yu, Yongwu; Li, Mingxv; Su, Ning; Zhang, Zhiyong; Zhao, Haidan; Yu, Hai; Xu, Yingluan

2016-02-01

Honokiol is the predominant active ingredient in the commonly used traditional Chinese medicine, Magnolia, which has been confirmed in previous studies to exhibit anti-oxidation, antimicrobial, antitumor and other pharmacological effects. However, its effects on renal ischemia/reperfusion injury (IRI) remain to be elucidated. The present study aimed to examine the effects of honokiol on renal IRI, and to investigate its potential protective mechanisms in the heart. Male adult Wistar albino rats were induced into a renal IRI model. Subsequently, the levels of serum creatinine, blood urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), and the levels of serum nitrite and the kidney nitrite were examined in the IRI group. The levels of oxidative stress, inducible nitric oxide synthase (iNOS), inflammatory factors and caspase-3 were evaluated using a series of commercially available kits. The levels of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) and the protein expression levels of STAT3 were determined using western blotting. Pretreatment with honokiol significantly reduced the levels of serum creatinine, BUN, ALT, AST and ALP, and the level of nitrite in the kidney of the IRI group, compared with the control group. The levels of malondialdehyde, the activity of myeloperoxidase, and the gene expression and activity of iNOS were reduced in the IRI rats, compared with the sham-operated rats, whereas the levels of superoxide dismutase and catalase were increased following treatment with honokiol in the IRI rats. In addition, the expression levels of tumor necrosis factor-α and interleukin-6 in the IRI rats were increased by honokiol. Treatment with honokiol suppressed the protein expression levels of p-STAT3 and caspase-3 in the IRI rats. These findings indicated that honokiol protects against renal IRI via the suppression of oxidative stress, iNOS, inflammation and STAT3 in the rat.

An examination of the roles of trauma exposure and posttraumatic stress disorder on emotion regulation strategies of Operation Iraqi Freedom, Operation Enduring Freedom, and Operation New Dawn veterans.

PubMed

Sippel, Lauren M; Roy, Alicia M; Southwick, Steven M; Fichtenholtz, Harlan M

2016-09-01

Theories of posttraumatic stress disorder (PTSD) implicate emotional processes, including difficulties utilizing adaptive emotion regulation strategies, as critical to the etiology and maintenance of PTSD. Operation Iraqi Freedom, Operation Enduring Freedom, and Operation New Dawn (OIF/OEF/OND) veterans report high levels of combat exposure and PTSD. We aimed to extend findings suggesting that emotion regulation difficulties are a function of PTSD, rather than combat trauma exposure or common comorbidities, to OIF/OEF/OND veterans, in order to inform models of PTSD risk and recovery that can be applied to returning veterans. We tested differences in emotion regulation, measured with the Difficulties in Emotion Regulation Scale and Emotion Regulation Questionnaire, among trauma-exposed veterans with (n = 24) or without PTSD (n = 22) and healthy civilian comparison participants (n = 27) using multivariate analyses of covariance, adjusting for major depressive disorder, anxiety disorders, and demographic variables (age, sex, and ethnicity). Veterans with PTSD reported more use of expressive suppression and more difficulties with emotion regulation than veterans without PTSD and healthy comparison participants. Groups did not differ on cognitive reappraisal. Findings suggest the key role of PTSD above and beyond trauma exposure, depression, and anxiety in specific aspects of emotion dysregulation among OIF/OEF/OND veterans. Interventions that help veterans expand and diversify their emotion regulation skills may serve as helpful adjunctive treatments for PTSD among OIF/OEF/OND veterans.

Deformability analysis of sickle blood using ektacytometry.

PubMed

Rabai, Miklos; Detterich, Jon A; Wenby, Rosalinda B; Hernandez, Tatiana M; Toth, Kalman; Meiselman, Herbert J; Wood, John C

2014-01-01

Sickle cell disease (SCD) is characterized by decreased erythrocyte deformability, microvessel occlusion and severe painful infarctions of different organs. Ektacytometry of SCD red blood cells (RBC) is made difficult by the presence of rigid, poorly-deformable irreversibly sickled cells (ISC) that do not align with the fluid shear field and distort the elliptical diffraction pattern seen with normal RBC. In operation, the computer software fits an outline to the diffraction pattern, then reports an elongation index (EI) at each shear stress based on the length and width of the fitted ellipse: EI=(length-width)/(length+width). Using a commercial ektacytometer (LORCA, Mechatronics Instruments, The Netherlands) we have approached the problem of ellipse fitting in two ways: (1) altering the height of the diffraction image on a computer monitor using an aperture within the camera lens; (2) altering the light intensity level (gray level) used by the software to fit the image to an elliptical shape. Neither of these methods affected deformability results (elongation index-shear stress relations) for normal RBC but did markedly affect results for SCD erythrocytes: (1) decreasing image height by 15% and 30% increased EI at moderate to high stresses; (2) progressively increasing the light level increased EI over a wide range of stresses. Fitting data obtained at different image heights using the Lineweaver-Burke routine yielded percentage ISC results in good agreement with microscopic cell counting. We suggest that these two relatively simple approaches allow minimizing artifacts due to the presence of rigid discs or ISC and also suggest the need for additional studies to evaluate the physiological relevance of deformability data obtained via these methods.

Can Physicians Identify Inappropriate Nuclear Stress Tests? An Examination of Inter-rater Reliability for the 2009 Appropriate Use Criteria for Radionuclide Imaging

PubMed Central

Ye, Siqin; Rabbani, LeRoy E.; Kelly, Christopher R.; Kelly, Maureen R.; Lewis, Matthew; Paz, Yehuda; Peck, Clara L.; Rao, Shaline; Bokhari, Sabahat; Weiner, Shepard D.; Einstein, Andrew J.

2014-01-01

Background We sought to determine inter-rater reliability of the 2009 Appropriate Use Criteria (AUC) for radionuclide imaging (RNI) and whether physicians at various levels of training can effectively identify nuclear stress tests with inappropriate indications. Methods and Results Four hundred patients were randomly selected from a consecutive cohort of patients undergoing nuclear stress testing at an academic medical center. Raters with different levels of training (including cardiology attending physicians, cardiology fellows, internal medicine hospitalists, and internal medicine interns) classified individual nuclear stress tests using the 2009 AUC. Consensus classification by two cardiologists was considered the operational gold standard, and sensitivity and specificity of individual raters for identifying inappropriate tests was calculated. Inter-rater reliability of the AUC was assessed using Cohen’s kappa statistics for pairs of different raters. The mean age of patients was 61.5 years; 214 (54%) were female. The cardiologists rated 256 (64%) of 400 NSTs as appropriate, 68 (18%) as uncertain, 55 (14%) as inappropriate; 21 (5%) tests were unable to be classified. Inter-rater reliability for non-cardiologist raters was modest (unweighted Cohen’s kappa, 0.51, 95% confidence interval, 0.45 to 0.55). Sensitivity of individual raters for identifying inappropriate tests ranged from 47% to 82%, while specificity ranged from 85% to 97%. Conclusions Inter-rater reliability for the 2009 AUC for RNI is modest, and there is considerable variation in the ability of raters at different levels of training to identify inappropriate tests. PMID:25563660

Role of Ribonucleotide Reductase in Bacillus subtilis Stress-Associated Mutagenesis.

PubMed

Castro-Cerritos, Karla Viridiana; Yasbin, Ronald E; Robleto, Eduardo A; Pedraza-Reyes, Mario

2017-02-15

The Gram-positive microorganism Bacillus subtilis relies on a single class Ib ribonucleotide reductase (RNR) to generate 2'-deoxyribonucleotides (dNDPs) for DNA replication and repair. In this work, we investigated the influence of RNR levels on B. subtilis stationary-phase-associated mutagenesis (SPM). Since RNR is essential in this bacterium, we engineered a conditional mutant of strain B. subtilis YB955 (hisC952 metB5 leu427) in which expression of the nrdEF operon was modulated by isopropyl-β-d-thiogalactopyranoside (IPTG). Moreover, genetic inactivation of ytcG, predicted to encode a repressor (NrdR) of nrdEF in this strain, dramatically increased the expression levels of a transcriptional nrdE-lacZ fusion. The frequencies of mutations conferring amino acid prototrophy in three genes were measured in cultures under conditions that repressed or induced RNR-encoding genes. The results revealed that RNR was necessary for SPM and overexpression of nrdEF promoted growth-dependent mutagenesis and SPM. We also found that nrdEF expression was induced by H 2 O 2 and such induction was dependent on the master regulator PerR. These observations strongly suggest that the metabolic conditions operating in starved B. subtilis cells increase the levels of RNR, which have a direct impact on SPM. Results presented in this study support the concept that the adverse metabolic conditions prevailing in nutritionally stressed bacteria activate an oxidative stress response that disturbs ribonucleotide reductase (RNR) levels. Such an alteration of RNR levels promotes mutagenic events that allow Bacillus subtilis to escape from growth-limited conditions. Copyright © 2017 American Society for Microbiology.

Blood cardioplegia with N-acetylcysteine may reduce coronary endothelial activation and myocardial oxidative stress.

PubMed

Rodrigues, Alfredo J; Evora, Paulo R B; Bassetto, Solange; Alves, Lafaiete; Scorzoni Filho, Adilson; Origuela, Eliana A; Vicente, Walter V A

2009-01-01

The aim of this prospective study was to compare the efficacy of intermittent antegrade blood cardioplegia with or without n-acetylcysteine (NAC) in reducing myocardial oxidative stress and coronary endothelial activation. Twenty patients undergoing elective isolated coronary artery bypass graft surgery were randomly assigned to receive intermittent antegrade blood cardioplegia (32 degrees C-34 degrees C) with (NAC group) or without (control group) 300 mg of NAC. For these 2 groups we compared clinical outcome, hemodynamic evolution, systemic plasmatic levels of troponin I, and plasma concentrations of malondialdehyde (MDA) and soluble vascular adhesion molecule 1 (sVCAM-1) from coronary sinus blood samples. Patient demographic characteristics and operative and postoperative data findings in both groups were similar. There was no hospital mortality. Comparing the plasma levels of MDA 10 min after the aortic cross-clamping and of sVCAM-1 30 min after the aortic cross-clamping period with the levels obtained before the aortic clamping period, we observed increases of both markers, but the increase was significant only in the control group (P= .039 and P= .064 for MDA; P= .004 and P= .064 for sVCAM-1). In both groups there was a significant increase of the systemic serum levels of troponin I compared with the levels observed before cardiopulmonary bypass (P< .001), but the differences between the groups were not significant (P= .570). Our investigation showed that NAC as an additive to blood cardioplegia in patients undergoing on-pump coronary artery bypass graft surgery may reduce oxidative stress and the resultant coronary endothelial activation.

Towards highly stable polymer electronics (Conference Presentation)

NASA Astrophysics Data System (ADS)

Nikolka, Mark; Nasrallah, Iyad; Broch, Katharina; Sadhanala, Aditya; Hurhangee, Michael; McCulloch, Iain; Sirringhaus, Henning

2016-11-01

Due to their ease of processing, organic semiconductors are promising candidates for applications in high performance flexible displays and fast organic electronic circuitry. Recently, a lot of advances have been made on organic semiconductors exhibiting surprisingly high performance and carrier mobilities exceeding those of amorphous silicon. However, there remain significant concerns about their operational and environmental stability, particularly in the context of applications that require a very high level of threshold voltage stability, such as active-matrix addressing of organic light-emitting diode (OLED) displays. Here, we report a novel technique for dramatically improving the operational stress stability, performance and uniformity of high mobility polymer field-effect transistors by the addition of specific small molecule additives to the polymer semiconductor film. We demonstrate for the first time polymer FETs that exhibit stable threshold voltages with threshold voltage shifts of less than 1V when subjected to a constant current operational stress for 1 day under conditions that are representative for applications in OLED active matrix displays. The approach constitutes in our view a technological breakthrough; it also makes the device characteristics independent of the atmosphere in which it is operated, causes a significant reduction in contact resistance and significantly improves device uniformity. We will discuss in detail the microscopic mechanism by which the molecular additives lead to this significant improvement in device performance and stability.

Chronic stress and sexual function in women

PubMed Central

Hamilton, Lisa Dawn; Meston, Cindy M.

2014-01-01

Introduction Chronic stress is known to have negative effects on reproduction, but little is known about how it affects the sexual response cycle. The present study examined the relationship between chronic stress and sexual arousal and the mechanisms that mediate this relationship. Aim To test the relationship between chronic stress and sexual arousal and identify mechanisms that may explain this relationship. We predicted that women experiencing high levels of chronic stress would show lower levels of genital arousal & DHEAS and higher levels of cortisol and cognitive distraction compared to women with average levels of stress. Methods Women who were categorized as high in chronic stress (high stress group, n = 15) or average in chronic stress (average stress group; n = 15) provided saliva samples and watched an erotic film while having their genital and psychological arousal measured. Main Outcome Measures Main outcome measures were vaginal pulse amplitude, psychological arousal, salivary cortisol, salivary DHEAS, and heart rate and compared them between women with high and average levels of chronic stress. Results Women in the high stress group had lower levels of genital, but not psychological arousal, had higher levels of cortisol, and reported more distraction during the erotic film than women in the average stress group. The main predictor of decreased genital sexual arousal was participants’ distraction scores. Conclusions High levels of chronic stress were related to lower levels of genital sexual arousal. Both psychological (distraction) and hormonal (increased cortisol) factors were related to the lower levels of sexual arousal seen in women high in chronic stress, but distraction was the only significant predictor when controlling for other variables. PMID:23841462

Short-term sleep disturbance-induced stress does not affect basal pain perception, but does delay postsurgical pain recovery

PubMed Central

Wang, Po-Kai; Cao, Jing; Wang, Hongzhen; Liang, Lingli; Zhang, Jun; Lutz, Brianna Marie; Shieh, Kun-Ruey; Bekker, Alex; Tao, Yuan-Xiang

2015-01-01

Chronic sleep disturbance-induced stress is known to increase basal pain sensitivity. However, most surgical patients frequently report short-term sleep disturbance/deprivation during pre- and post-operation periods and have normal pain perception pre-surgery. Whether this short-term sleep disturbance affects postsurgical pain is elusive. We here reported that pre- or post-exposure to rapid eye movement sleep disturbance (REMSD) 6 h daily for 3 consecutive days did not alter basal responses to mechanical, heat, and cold stimuli, but did delay recovery in incision-induced reductions in paw withdrawal threshold to mechanical stimulation and paw withdrawal latencies to heat and cold stimuli on the ipsilateral side of male or female rats. This short-term REMSD led to stress evidenced by an increase in swim immobility time, a decrease in sucrose consumption, and an elevation in the level of corticosterone in serum. Blocking this stress via intrathecal RU38486 or bilateral adrenalectomy abolished REMSD-caused delay in recovery of incision-induced reductions in behavioral responses to mechanical, heat, and cold stimuli. Moreover, this short-term REMSD produced significant reductions in the levels of mu opioid receptor and kappa opioid receptor, but not Kv1.2, in the ipsilateral L4/5 spinal cord and dorsal root ganglia on day 9 post-incision (but not post-sham surgery). PMID:26342649

Neuroprotective and Blood-Retinal Barrier-Preserving Effects of Cannabidiol in Experimental Diabetes

PubMed Central

El-Remessy, Azza B.; Al-Shabrawey, Mohamed; Khalifa, Yousuf; Tsai, Nai-Tse; Caldwell, Ruth B.; Liou, Gregory I.

2006-01-01

Diabetic retinopathy is characterized by blood-retinal barrier (BRB) breakdown and neurotoxicity. These pathologies have been associated with oxidative stress and proinflammatory cytokines, which may operate by activating their downstream target p38 MAP kinase. In the present study, the protective effects of a nonpsychotropic cannabinoid, cannabidiol (CBD), were examined in streptozotocin-induced diabetic rats after 1, 2, or 4 weeks. Retinal cell death was determined by terminal dUTP nick-end labeling assay; BRB function by quantifying extravasation of bovine serum albumin-fluorescein; and oxidative stress by assays for lipid peroxidation, dichlorofluorescein fluorescence, and tyrosine nitration. Experimental diabetes induced significant increases in oxidative stress, retinal neuronal cell death, and vascular permeability. These effects were associated with increased levels of tumor necrosis factor-α, vascular endothelial growth factor, and intercellular adhesion molecule-1 and activation of p38 MAP kinase, as assessed by enzyme-linked immunosorbent assay, immunohistochemistry, and/or Western blot. CBD treatment significantly reduced oxidative stress; decreased the levels of tumor necrosis factor-α, vascular endothelial growth factor, and intercellular adhesion molecule-1; and prevented retinal cell death and vascular hyperpermeability in the diabetic retina. Consistent with these effects, CBD treatment also significantly inhibited p38 MAP kinase in the diabetic retina. These results demonstrate that CBD treatment reduces neurotoxicity, inflammation, and BRB breakdown in diabetic animals through activities that may involve inhibition of p38 MAP kinase. PMID:16400026

Protective role of glycerol against benzene stress: insights from the Pseudomonas putida proteome.

PubMed

Bhaganna, Prashanth; Bielecka, Agata; Molinari, Gabriella; Hallsworth, John E

2016-05-01

Chemical activities of hydrophobic substances can determine the windows of environmental conditions over which microbial systems function and the metabolic inhibition of microorganisms by benzene and other hydrophobes can, paradoxically, be reduced by compounds that protect against cellular water stress (Bhaganna et al. in Microb Biotechnol 3:701-716, 2010; Cray et al. in Curr Opin Biotechnol 33:228-259, 2015a). We hypothesized that this protective effect operates at the macromolecule structure-function level and is facilitated, in part at least, by genome-mediated adaptations. Based on proteome profiling of the soil bacterium Pseudomonas putida, we present evidence that (1) benzene induces a chaotrope-stress response, whereas (2) cells cultured in media supplemented with benzene plus glycerol were protected against chaotrope stress. Chaotrope-stress response proteins, such as those involved in lipid and compatible-solute metabolism and removal of reactive oxygen species, were increased by up to 15-fold in benzene-stressed cells relative to those of control cultures (no benzene added). By contrast, cells grown in the presence of benzene + glycerol, even though the latter grew more slowly, exhibited only a weak chaotrope-stress response. These findings provide evidence to support the hypothesis that hydrophobic substances induce a chaotropicity-mediated water stress, that cells respond via genome-mediated adaptations, and that glycerol protects the cell's macromolecular systems. We discuss the possibility of using compatible solutes to mitigate hydrocarbon-induced stresses in lignocellulosic biofuel fermentations and for industrial and environmental applications.

Multi-scale analysis and characterization of the ITER pre-compression rings

NASA Astrophysics Data System (ADS)

Foussat, A.; Park, B.; Rajainmaki, H.

2014-01-01

The toroidal field (TF) system of ITER Tokamak composed of 18 "D" shaped Toroidal Field (TF) coils during an operating scenario experiences out-of-plane forces caused by the interaction between the 68kA operating TF current and the poloidal magnetic fields. In order to keep the induced static and cyclic stress range in the intercoil shear keys between coils cases within the ITER allowable limits [1], centripetal preload is introduced by means of S2 fiber-glass/epoxy composite pre-compression rings (PCRs). Those PCRs consist in two sets of three rings, each 5 m in diameter and 337 × 288 mm in cross-section, and are installed at the top and bottom regions to apply a total resultant preload of 70 MN per TF coil equivalent to about 400 MPa hoop stress. Recent developments of composites in the aerospace industry have accelerated the use of advanced composites as primary structural materials. The PCRs represent one of the most challenging composite applications of large dimensions and highly stressed structures operating at 4 K over a long term life. Efficient design of those pre-compression composite structures requires a detailed understanding of both the failure behavior of the structure and the fracture behavior of the material. Due to the inherent difficulties to carry out real scale testing campaign, there is a need to develop simulation tools to predict the multiple complex failure mechanisms in pre-compression rings. A framework contract was placed by ITER Organization with SENER Ingenieria y Sistemas SA to develop multi-scale models representative of the composite structure of the Pre-compression rings based on experimental material data. The predictive modeling based on ABAQUS FEM provides the opportunity both to understand better how PCR composites behave in operating conditions and to support the development of materials by the supplier with enhanced performance to withstand the machine design lifetime of 30,000 cycles. The multi-scale stress analysis has revealed a complete picture of the stress levels within the fiber and the matrix regarding the static and fatigue performance of the rings structure including the presence of a delamination defect of critical size. The analysis results of the composite material demonstrate that the rings performance objectives under all loading and strength conditions are met.

Early life stress is a risk factor for excessive alcohol drinking and impulsivity in adults and is mediated via a CRF/GABA(A) mechanism.

PubMed

Gondré-Lewis, Marjorie C; Warnock, Kaitlin T; Wang, Hong; June, Harry L; Bell, Kimberly A; Rabe, Holger; Tiruveedhula, Veera Venkata Naga Phani Babu; Cook, James; Lüddens, Hartmut; Aurelian, Laure; June, Harry L

2016-01-01

Childhood stress and trauma are associated with substance use disorders in adulthood, but the neurological changes that confer increased vulnerability are largely unknown. In this study, maternal separation (MS) stress, restricted to the pre-weaning period, was used as a model to study mechanisms of protracted effects of childhood stress/traumatic experiences on binge drinking and impulsivity. Using an operant self-administration model of binge drinking and a delay discounting assay to measure impulsive-like behavior, we report that early life stress due to MS facilitated acquisition of binge drinking and impulsivity during adulthood in rats. Previous studies have shown heightened levels of corticotropin releasing factor (CRF) after MS, and here, we add that MS increased expression levels of GABA(A) α2 subunit in central stress circuits. To investigate the precise role of these circuits in regulating impulsivity and binge drinking, the CRF1 receptor antagonist antalarmin and the novel GABA(A) α2 subunit ligand 3-PBC were infused into the central amygdala (CeA) and medial prefrontal cortex (mPFC). Antalarmin and 3-PBC at each site markedly reduced impulsivity and produced profound reductions on binge-motivated alcohol drinking, without altering responding for sucrose. Furthermore, whole-cell patch-clamp studies showed that low concentrations of 3-PBC directly reversed the effect of relatively high concentrations of ethanol on α2β3γ2 GABA(A) receptors, by a benzodiazepine site-independent mechanism. Together, our data provide strong evidence that maternal separation, i.e. early life stress, is a risk factor for binge drinking, and is linked to impulsivity, another key risk factor for excessive alcohol drinking. We further show that pharmacological manipulation of CRF and GABA receptor signaling is effective to reverse binge drinking and impulsive-like behavior in MS rats. These results provide novel insights into the role of the brain stress systems in the development of impulsivity and excessive alcohol consumption.

Using Propranolol to Block Memory Reconsolidation in Female Veterans with PTSD

DTIC Science & Technology

2015-11-01

13. SUPPLEMENTARY NOTES 14. ABSTRACT One of the hallmark features of Posttraumatic Stress Disorder (PTSD) is a marked increased in physical arousal ... arousal of a traumatic memory to less-impairing levels may do well in allowing an individual with PTSD to return to his or her daily life. However, there...occur in women. Our research investigates a novel method of reducing the hyper- arousal associated with combat memories in Female Operation Iraqi

A Framework for Matching User Needs to an Optimal Level of Office Automation

DTIC Science & Technology

1988-06-01

TECHNOSTRESS Craig Brod coins the term " technostress " to describe the emotional stress induced by the introduction of new technology. (Brod, 1984, pp. 28... Technostress has a very negative effect on the productivity of people who use OA systems. Common indicators of technostress are very slow learning... technostress using a strategy which divides adaptation to computers into three phases called orientation, operations and mastery. 59 1. Orientation The

Joint Center for Operational Analysis Journal. Volume 9, Issue 3, September 2007

DTIC Science & Technology

2007-09-01

to be capable of guarding the states “against those violent and oppressive fac- tions which embitter the blessings of liberty.”21 The Constitution...disaster response. Whether it was a good or bad precedent depends on which level of government you are viewing it from. Initially, guardsmen were...likely be stressed to reimburse the federal government. Relationship to EMAC Generally, when states require assistance beyond their resources, they

Review of Studies of Mechanoelectrical Transformations in Rocks in Russia and Abroad

NASA Astrophysics Data System (ADS)

Pomishin, E.; Yavorovich, L.

2016-06-01

The problem of monitoring and forecast of dynamic manifestations of rock masses becomes immediate in the mining industry because of the growth of mining work intensity and changeover to the mining operations in deeper levels. The article presents a short review of the scientific works of foreign researchers for more complete and in-depth study of geophysical methods of control of the stress-strain state and bump hazard of rock masses.

Electrostatic Discharge (ESD) Susceptibility of Electronic Devices

DTIC Science & Technology

1983-01-01

determined by knowing the thermal environment in which the component is to operate. However, ESD is not that predictable . It is considered a random... predicted where a part may experience an ESD pulse during usage? (3) What effect does stressing a device with different models have on its propensity for...relatively low ESO threshold voltages (i.e., < 7000 volts) tend to be consistently high compared with their predicted level using EMP data. But at

Effects of ovariectomy and resistance training on oxidative stress markers in the rat liver

PubMed Central

Rodrigues, Maria Fernanda Cury; Stotzer, Uliana Sbeguen; Domingos, Mateus Moraes; Deminice, Rafael; Shiguemoto, Gilberto Eiji; Tomaz, Luciane Magri; de Sousa, Nuno Manuel Frade; Ferreira, Fabiano Candido; Leite, Richard Diego; Selistre-de-Araújo, Heloisa Sobreiro; Jordão-Júnior, Alceu Afonso; Baldissera, Vilmar; de Andrade Perez, Sérgio Eduardo

2013-01-01

OBJECTIVE: The objective of this study was to assess the effects of resistance training on oxidative stress markers in the livers of ovariectomized rats. METHOD: Adult Sprague-Dawley rats were divided into the following four groups (n = 8 per group): sham-operated sedentary, ovariectomized sedentary, sham-operated resistance training, and ovariectomized resistance training. During the resistance training period, the animals climbed a 1.1-m vertical ladder with weights attached to their tails; the sessions were conducted 3 times per week, with 4-9 climbs and 8-12 dynamic movements per climb. The oxidative stress was assessed by measuring the levels of reduced glutathione and oxidized glutathione, the enzymatic activity of catalase and superoxide dismutase, lipid peroxidation, vitamin E concentrations, and the gene expression of glutathione peroxidase. RESULTS: The results showed significant reductions in the reduced glutathione/oxidized glutathione ratio (4.11±0.65 nmol/g tec), vitamin E concentration (55.36±11.11 nmol/g), and gene expression of glutathione peroxidase (0.49±0.16 arbitrary units) in the livers of ovariectomized rats compared with the livers of unovariectomized animals (5.71±0.71 nmol/g tec, 100.14±10.99 nmol/g, and 1.09±0.54 arbitrary units, respectively). Moreover, resistance training for 10 weeks was not able to reduce the oxidative stress in the livers of ovariectomized rats and induced negative changes in the hepatic anti-oxidative/oxidative balance. CONCLUSION: Our findings indicate that the resistance training program used in this study was not able to attenuate the hepatic oxidative damage caused by ovariectomy and increased the hepatic oxidative stress. PMID:24141842

Effects of ovariectomy and resistance training on oxidative stress markers in the rat liver.

PubMed

Rodrigues, Maria Fernanda Cury; Stotzer, Uliana Sbeguen; Domingos, Mateus Moraes; Deminice, Rafael; Shiguemoto, Gilberto Eiji; Tomaz, Luciane Magri; Sousa, Nuno Manuel Frade de; Ferreira, Fabiano Candido; Leite, Richard Diego; Selistre-de-Araújo, Heloisa Sobreiro; Jordão-Júnior, Alceu Afonso; Baldissera, Vilmar; Perez, Sérgio Eduardo de Andrade

2013-09-01

The objective of this study was to assess the effects of resistance training on oxidative stress markers in the livers of ovariectomized rats. Adult Sprague-Dawley rats were divided into the following four groups (n = 8 per group): sham-operated sedentary, ovariectomized sedentary, sham-operated resistance training, and ovariectomized resistance training. During the resistance training period, the animals climbed a 1.1-m vertical ladder with weights attached to their tails; the sessions were conducted 3 times per week, with 4-9 climbs and 8-12 dynamic movements per climb. The oxidative stress was assessed by measuring the levels of reduced glutathione and oxidized glutathione, the enzymatic activity of catalase and superoxide dismutase, lipid peroxidation, vitamin E concentrations, and the gene expression of glutathione peroxidase. The results showed significant reductions in the reduced glutathione/oxidized glutathione ratio (4.11±0.65 nmol/g tec), vitamin E concentration (55.36±11.11 nmol/g), and gene expression of glutathione peroxidase (0.49±0.16 arbitrary units) in the livers of ovariectomized rats compared with the livers of unovariectomized animals (5.71±0.71 nmol/g tec, 100.14±10.99 nmol/g, and 1.09±0.54 arbitrary units, respectively). Moreover, resistance training for 10 weeks was not able to reduce the oxidative stress in the livers of ovariectomized rats and induced negative changes in the hepatic anti-oxidative/oxidative balance. Our findings indicate that the resistance training program used in this study was not able to attenuate the hepatic oxidative damage caused by ovariectomy and increased the hepatic oxidative stress.

The Impact of Operating Room Distractions on Stress, Workload, and Teamwork.

PubMed

Wheelock, Ana; Suliman, Amna; Wharton, Rupert; Babu, E D; Hull, Louise; Vincent, Charles; Sevdalis, Nick; Arora, Sonal

2015-06-01

To investigate whether distractions in the operating room (OR) are associated with higher mental workload and stress, and poorer teamwork among OR personnel. Engaging in multiple tasks can affect performance. There is little research on the effect of distractions on surgical team members' behavior and cognitive processes. Ninety general surgery cases were observed in real time. Cases were assessed by a surgeon and a behavioral scientist using 4 validated tools: OR Distractions Assessment Form, the Observational Teamwork Assessment for Surgery tool, NASA-Task Load Index, and short form of the State Trait Anxiety Inventory. Analysis of variance was performed to evaluate significant differences between teamwork, workload, and stress level among team members. Correlations (Pearson r) were computed to evaluate associations between variables. The most prevalent distractions were those initiated by external staff, followed by case-irrelevant conversations. Case-irrelevant conversations were associated with poorer team performance. Irrelevant conversations initiated by surgeons were associated with lower teamwork in surgeons (across team skills: r = -0.44 to -0.58, P < 0.05 to 0.01) and anesthesiologists (r = -0.38 and r = -0.40, for coordination and leadership; P < 0.05). Equipment-related distractions correlated with higher stress (r = 0.48, P < 0.05) and lower teamwork (across team skills: r = -0.42 to -0.50, P < 0.05) in nurses. Acoustic distractions correlated with higher stress in surgeons (r = 0.32, P < 0.05) and higher workload in anesthesiologists (r = 0.30, P < 0.05). Although some distractions may be inevitable in the OR, they can also be detrimental to the team. A deeper understanding of the effect of distractions on teams and their outcomes can lead to targeted quality improvement.

Residual stresses and vector hysteresis modeling

NASA Astrophysics Data System (ADS)

Ktena, Aphrodite

2016-04-01

Residual stresses in magnetic materials, whether the result of processing or intentional loading, leave their footprint on macroscopic data, such hysteresis loops and differential permeability measurements. A Preisach-type vector model is used to reproduce the phenomenology observed based on assumptions deduced from the data: internal stresses lead to smaller and misaligned grains, hence increased domain wall pinning and angular dispersion of local easy axes, favouring rotation as a magnetization reversal mechanism; misaligned grains contribute to magnetostatic fields opposing the direction of the applied field. The model is using a vector operator which accounts for both reversible and irreversible processes; the Preisach concept for interactions for the role of stress related demagnetizing fields; and a characteristic probability density function which is constructed as a weighed sum of constituent functions: the material is modeled as consisting of various subsystems, e.g. reversal mechanisms or areas subject to strong/weak long range interactions and each subsystem is represented by a constituent probability density function. Our assumptions are validated since the model reproduces the hysteresis loops and differential permeability curves observed experimentally and calculations involving rotating inputs at various residual stress levels are consistent and in agreement with experimental evidence.

Numerical simulation of fluid flow in a rotational bioreactor

NASA Astrophysics Data System (ADS)

Ganimedov, V. L.; Papaeva, E. O.; Maslov, N. A.; Larionov, P. M.

2017-10-01

Application of scaffold technology for the problem of bone tissue regeneration has great prospects in modern medicine. The influence of fluid shear stress on stem cells cultivation and its differentiation into osteoblasts is the subject of intensive research. Mathematical modeling of fluid flow in bioreactor allowed us to determine the structure of flow and estimate the level of mechanical stress on cells. The series of computations for different rotation frequencies (0.083, 0.124, 0.167, 0.2 and 0.233 Hz) was performed for the laminar flow regime approximation. It was shown that the Taylor vortices in the gap between the cylinders qualitatively change the distribution of static pressure and shear stress in the region of vortices connection. It was shown that an increase in the rotation frequency leads to an increase of the unevenness in distribution of the above mentioned functions. The obtained shear stress and static pressure dependence on the rotational frequency make it possible to choose the operating mode of the reactor depending on the provided requirements. It was shown that in the range of rotation frequencies chosen in this work (0.083 < f < 0.233 Hz), the shear stress does not exceed the known literature data (0.002 - 0.1 Pa).

Perceived Stress at Work Is Associated with Lower Levels of DHEA-S

PubMed Central

Lennartsson, Anna-Karin; Theorell, Töres; Rockwood, Alan L.; Kushnir, Mark M.; Jonsdottir, Ingibjörg H.

2013-01-01

Background It is known that long-term psychosocial stress may cause or contribute to different diseases and symptoms and accelerate aging. One of the consequences of prolonged psychosocial stress may be a negative effect on the levels of dehydroepiandrosterone (DHEA) and its sulphated metabolite dehydroepiandrosterone sulphate (DHEA-S). The aim of this study is to investigate whether levels of DHEA and DHEA-S differ in individuals who report perceived stress at work compared to individuals who report no perceived stress at work. Methods Morning fasting DHEA-S and DHEA levels were measured in serum in a non-stressed group (n = 40) and a stressed group (n = 41). DHEA and DHEA-S levels were compared between the groups using ANCOVA, controlling for age. Results The mean DHEA-S levels were 23% lower in the subjects who reported stress at work compared to the non-stressed group. Statistical analysis (ANCOVA) showed a significant difference in DHEA-S levels between the groups (p = 0.010). There was no difference in DHEA level between the groups. Conclusions This study indicates that stressed individual have markedly lower levels of DHEA-S. Given the important and beneficial functions of DHEA and DHEA-S, lower levels of DHEA-S may constitute one link between psychosocial stress, ill health and accelerated ageing. PMID:24015247

Perceived stress at work is associated with lower levels of DHEA-S.

PubMed

Lennartsson, Anna-Karin; Theorell, Töres; Rockwood, Alan L; Kushnir, Mark M; Jonsdottir, Ingibjörg H

2013-01-01

It is known that long-term psychosocial stress may cause or contribute to different diseases and symptoms and accelerate aging. One of the consequences of prolonged psychosocial stress may be a negative effect on the levels of dehydroepiandrosterone (DHEA) and its sulphated metabolite dehydroepiandrosterone sulphate (DHEA-S). The aim of this study is to investigate whether levels of DHEA and DHEA-S differ in individuals who report perceived stress at work compared to individuals who report no perceived stress at work. Morning fasting DHEA-S and DHEA levels were measured in serum in a non-stressed group (n = 40) and a stressed group (n = 41). DHEA and DHEA-S levels were compared between the groups using ANCOVA, controlling for age. The mean DHEA-S levels were 23% lower in the subjects who reported stress at work compared to the non-stressed group. Statistical analysis (ANCOVA) showed a significant difference in DHEA-S levels between the groups (p = 0.010). There was no difference in DHEA level between the groups. This study indicates that stressed individual have markedly lower levels of DHEA-S. Given the important and beneficial functions of DHEA and DHEA-S, lower levels of DHEA-S may constitute one link between psychosocial stress, ill health and accelerated ageing.

Medical ozone therapy reduces oxidative stress and testicular damage in an experimental model of testicular torsion in rats.

PubMed

Tusat, Mustafa; Mentese, Ahmet; Demir, Selim; Alver, Ahmet; Imamoglu, Mustafa

2017-01-01

Testicular torsion (TT) refers to rotation of the testis and twisting of the spermatic cord. TT results in ischemia-reperfusion (I/R) injury involving increased oxidative stress, inflammation and apoptosis, and can even lead to infertility. The aim of this study was to investigate the effect of ozone therapy on testicular damage due to I/R injury in an experimental torsion model. 24 male Sprague-Dawley rats were divided into 3 groups; sham-operated, torsion/detorsion (T/D), and T/D+ozone. Ozone (1mg/kg) was injected intraperi-toneally 120 minutes before detorsion and for the following 24h. Blood and tissue samples were collected at the end of 24h. Johnsen score, ischemia modified albumin (IMA), total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) levels were determined. Levels of IMA, TOS, OSI, and histopathological scores increased in the serum/tissue of the rats in the experimental T/D group. Serum IMA, TOS, and OSI levels and tissue histo-pathological scores were lower in the rats treated with ozone compared with the T/D group. Our study results suggest that ozone therapy may exhibit beneficial effects on both biochemical and histopathological findings. Clinical trials are now necessary to confirm this. Copyright® by the International Brazilian Journal of Urology.

Time Savings and Surgery Task Load Reduction in Open Intraperitoneal Onlay Mesh Fixation Procedure.

PubMed

Roy, Sanjoy; Hammond, Jeffrey; Panish, Jessica; Shnoda, Pullen; Savidge, Sandy; Wilson, Mark

2015-01-01

This study assessed the reduction in surgeon stress associated with savings in procedure time for mechanical fixation of an intraperitoneal onlay mesh (IPOM) compared to a traditional suture fixation in open ventral hernia repair. Nine general surgeons performed 36 open IPOM fixation procedures in porcine model. Each surgeon conducted two mechanical (using ETHICON SECURESTRAP ™ Open) and two suture fixation procedures. Fixation time was measured using a stopwatch, and related surgeon stress was assessed using the validated SURG-TLX questionnaire. T-tests were used to compare between-group differences, and a two-sided 95% confidence interval for the difference in stress levels was established using nonparametric methodology. The mechanical fixation group demonstrated an 89.1% mean reduction in fixation time, as compared to the suture group (p < 0.00001). Surgeon stress scores measured using SURG-TLX were 55.5% lower in the mechanical compared to the suture fixation group (p < 0.001). Scores in five of the six sources of stress were significantly lower for mechanical fixation. Mechanical fixation with ETHICON SECURESTRAP ™ Open demonstrated a significant reduction in fixation time and surgeon stress, which may translate into improved operating efficiency, improved performance, improved surgeon quality of life, and reduced overall costs of the procedure.

Time Savings and Surgery Task Load Reduction in Open Intraperitoneal Onlay Mesh Fixation Procedure

PubMed Central

Roy, Sanjoy; Hammond, Jeffrey; Panish, Jessica; Shnoda, Pullen; Savidge, Sandy; Wilson, Mark

2015-01-01

Background. This study assessed the reduction in surgeon stress associated with savings in procedure time for mechanical fixation of an intraperitoneal onlay mesh (IPOM) compared to a traditional suture fixation in open ventral hernia repair. Study Design. Nine general surgeons performed 36 open IPOM fixation procedures in porcine model. Each surgeon conducted two mechanical (using ETHICON SECURESTRAPTM Open) and two suture fixation procedures. Fixation time was measured using a stopwatch, and related surgeon stress was assessed using the validated SURG-TLX questionnaire. T-tests were used to compare between-group differences, and a two-sided 95% confidence interval for the difference in stress levels was established using nonparametric methodology. Results. The mechanical fixation group demonstrated an 89.1% mean reduction in fixation time, as compared to the suture group (p < 0.00001). Surgeon stress scores measured using SURG-TLX were 55.5% lower in the mechanical compared to the suture fixation group (p < 0.001). Scores in five of the six sources of stress were significantly lower for mechanical fixation. Conclusions. Mechanical fixation with ETHICON SECURESTRAPTM Open demonstrated a significant reduction in fixation time and surgeon stress, which may translate into improved operating efficiency, improved performance, improved surgeon quality of life, and reduced overall costs of the procedure. PMID:26240834

Chronic Trauma Effects on Personality Traits in Police Officers.

PubMed

Leigh Wills, Jennifer; Schuldberg, David

2016-04-01

The impact of cumulative occupational exposure to traumatic events (TEs), posttraumatic stress (PTS) symptoms, and work environment stress on personality traits over time was examined in 38 police officers from an urban agency. California Psychological Inventory (CPI) personality trait scores from prehire evaluations were compared with follow-up CPI scores to test whether exposure to traumatic events was correlated with changes in traits from baseline to 5-10 years later. Measures of occupational TEs, PTS symptoms, and police work environment stress were administered. Mean trait scores declined on all CPI traits analyzed in the study. Trait change was evaluated using the Reliable Change Index; change in participants' scores unlikely to occur by chance ranged from 11% to 63% in the traits examined. All participants reported substantial TE exposure. PTS symptoms were correlated with steeper decline in 4 of 5 traits, with effect sizes ranging from r =  -.47 to r = -.67. Scores on measures of job-related TEs were negatively correlated with only one CPI trait (empathy) at T2 (r = -.31), and were unrelated to slope of trait change. Work environment stress was significantly related to gender, with female officers reporting higher levels of operational (r = .45) and organizational (r = .54) stress. Copyright © 2016 International Society for Traumatic Stress Studies.

High intensity scenario training of military medical students to increase learning capacity and management of stress response.

PubMed

Mueller, Genevieve R; Moloff, Alan L; Wedmore, Ian S; Schoeff, Jonathan E; Laporta, Anthony J

2012-01-01

A delicate balance exists between a beneficial stress response that enhances memory and recall performance and a detrimental high stress response that impairs memory and learning. Repetitive training in stressful situations enables people to lower their stress levels from the detrimental range to a more beneficial one.1 This is particularly true for physicians in training as they seek to achieve advanced skills and knowledge in the fields of triage, emergency medicine, and surgery prior to graduation. This need is significant for medical students entering military service after graduation. We theorize that military medical students can advance their proficiencies through an Intensive Skills Week (ISW) prior to entering their third and forth year rotations. To test this theory, Rocky Vista University will hold a week long high-intensity first-responder, emergency medicine and surgical training course, facilitated by military medical physicians, to further students? skills and maximize training using the Human Worn Partial Surgical Task Simulator (Cut Suit). We also see the possible benefit to physician and non-physician military personnel, especially Special Operations Forces (SOF) medical personnel, from developing and implementing similar training programs when live tissue or cadaver models are unavailable or not feasible. Stress, cortisol, medical student, enhanced learning, scenario, high intensity. 2012.

Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells.

PubMed

Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

2016-08-05

The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4-5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba(2+)-sensitive inward rectifier K(+) current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level but not at mRNA level after the hypoxic culture. Ca(2+) imaging study revealed that the hypoxic stress enhanced store-operated Ca(2+) (SOC) entry, which was significantly reduced in the presence of 100 μM Ba(2+). On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba(2+). We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca(2+) entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of sulfonylureas administered centrally on the blood glucose level in immobilization stress model.

PubMed

Sharma, Naveen; Sim, Yun-Beom; Park, Soo-Hyun; Lim, Su-Min; Kim, Sung-Su; Jung, Jun-Sub; Hong, Jae-Seung; Suh, Hong-Won

2015-05-01

Sulfonylureas are widely used as an antidiabetic drug. In the present study, the effects of sulfonylurea administered supraspinally on immobilization stress-induced blood glucose level were studied in ICR mice. Mice were once enforced into immobilization stress for 30 min and returned to the cage. The blood glucose level was measured 30, 60, and 120 min after immobilization stress initiation. We found that intracerebroventricular (i.c.v.) injection with 30 µg of glyburide, glipizide, glimepiride or tolazamide attenuated the increased blood glucose level induced by immobilization stress. Immobilization stress causes an elevation of the blood corticosterone and insulin levels. Sulfonylureas pretreated i.c.v. caused a further elevation of the blood corticosterone level when mice were forced into the stress. In addition, sulfonylureas pretreated i.c.v. alone caused an elevation of the plasma insulin level. Furthermore, immobilization stress-induced insulin level was reduced by i.c.v. pretreated sulfonylureas. Our results suggest that lowering effect of sulfonylureas administered supraspinally against immobilization stress-induced increase of the blood glucose level appears to be primarily mediated via elevation of the plasma insulin level.

Changes in smoking habits of smokers under bombing by rockets.

PubMed

Keinan-Boker, L; Enav, T; Rozentraub, T; Shohat, T

2011-03-01

Stress is known to impact smoking. This survey assessed changes in smoking behaviour of smokers in Southern Israel during a military operation (December 2008-January 2009) that exposed several civilian communities to intensive rocket bombing and acute stress. Households with an active land telephone line in Jewish Gaza vicinity communities were sampled. Inclusion criteria were age (18+ years) and being a daily or an occasional smoker. A telephone interview was carried out, focusing on socio-demographic characteristics and change in smoking behaviour during the military operation. Personal, demographic and circumstantial correlates of smoking behaviour were assessed using univariate and multivariate analyses. A total of 425 smokers took part in the survey. Most (85%) reported being daily smokers, and smoked, on average, 10-20 cigarettes/day before the operation. During the operation, 38% of the smokers changed their smoking habits and most (88%) reported higher than usual smoking rates. Correlates significantly associated with higher smoking during the operation were sex (female), education (lower) and not working due to the operation. Exposure to acute stress has an impact on smoking rates, especially in certain subgroups of smokers. Relevant smoking cessation interventions should address the special needs of smokers exposed to stressful circumstances.

Cylinder valve packing nut studies

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

Blue, S.C.

1991-12-31

The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

Chronic stress and sexual function in women.

PubMed

Hamilton, Lisa Dawn; Meston, Cindy M

2013-10-01

Chronic stress is known to have negative effects on reproduction, but little is known about how it affects the sexual response cycle. The present study examined the relationship between chronic stress and sexual arousal and the mechanisms that mediate this relationship. The aim of this study is to test the relationship between chronic stress and sexual arousal and identify mechanisms that may explain this relationship. We predicted that women experiencing high levels of chronic stress would show lower levels of genital arousal and dehydroepiandrosterone (DHEAS) and higher levels of cortisol and cognitive distraction compared with women with average levels of stress. Women who were categorized as high in chronic stress (high stress group; n=15) or average in chronic stress (average stress group; n=15) provided saliva samples and watched an erotic film while having their genital and psychological arousal measured. Main outcome measures were vaginal pulse amplitude, psychological arousal, salivary cortisol, salivary DHEAS, and heart rate and compared them between women with high and average levels of chronic stress. Women in the high stress group had lower levels of genital, but not psychological arousal, had higher levels of cortisol, and reported more distraction during the erotic film than women in the average stress group. The main predictor of decreased genital sexual arousal was participants' distraction scores. High levels of chronic stress were related to lower levels of genital sexual arousal. Both psychological (distraction) and hormonal (increased cortisol) factors were related to the lower levels of sexual arousal seen in women high in chronic stress, but distraction was the only significant predictor when controlling for other variables. © 2013 International Society for Sexual Medicine.

Metal Matrix Superconductor Composites for SMES-Driven, Ultra High Power BEP Applications: Part 2

NASA Astrophysics Data System (ADS)

Gross, Dan A.; Myrabo, Leik N.

2006-05-01

A 2.5 TJ superconducting magnetic energy storage (SMES) design presentation is continued from the preceding paper (Part 1) with electromagnetic and associated stress analysis. The application of interest is a rechargeable power-beaming infrastructure for manned microwave Lightcraft operations. It is demonstrated that while operational performance is within manageable parameter bounds, quench (loss of superconducting state) imposes enormous electrical stresses. Therefore, alternative multiple toroid modular configurations are identified, alleviating simultaneously all excessive stress conditions, operational and quench, in the structural, thermal and electromagnetic sense — at some reduction in specific energy, but presenting programmatic advantages for a lengthy technology development, demonstration and operation schedule. To this end several natural units, based on material properties and operating parameters are developed, in order to identify functional relationships and optimization paths more effectively.

Effect of the Leveling Conditions on Residual Stress Evolution of Hot Rolled High Strength Steels for Cold Forming

NASA Astrophysics Data System (ADS)

Park, Keecheol; Oh, Kyungsuk

2017-09-01

In order to investigate the effect of leveling conditions on residual stress evolution during the leveling process of hot rolled high strength steels, the in-plane residual stresses of sheet processed under controlled conditions at skin-pass mill and levelers were measured by cutting method. The residual stress was localized near the edge of sheet. As the thickness of sheet was increased, the residual stress occurred region was expanded. The magnitude of residual stress within the sheet was reduced as increasing the deformation occurred during the leveling process. But the residual stress itself was not removed completely. The magnitude of camber occurred at cut plate was able to be predicted by the residual stress distribution. A numerical algorithm was developed for analysing the effect of leveling conditions on residual stress. It was able to implement the effect of plastic deformation in leveling, tension, work roll bending, and initial state of sheet (residual stress and curl distribution). The validity of simulated results was verified from comparison with the experimentally measured residual stress and curl in a sheet.

Glutamine decreases the duration of postoperative ileus after abdominal surgery: an experimental study of conscious dogs.

PubMed

Ohno, Tetsuro; Mochiki, Erito; Ando, Hiroyuki; Fukasawa, Takaharu; Toyomasu, Yoshitaka; Ogata, Kyoichi; Aihara, Ryuusuke; Asao, Takayuki; Kuwano, Hiroyuki

2009-06-01

Postoperative ileus (POI) is a transient bowel dysmotility that occurs following many types of operations and is one of the most common complications of gastrointestinal surgery. We hypothesized that enteral supplementation of glutamine after abdominal surgery would restore fuel to the small intestine, suppress oxidative stress, and lead to improvement in POI. Twelve dogs underwent distal gastrectomy and were each randomly assigned to one of two groups based on postoperative treatment: the water injection (control) group and the glutamine injection group. Water (40 ml) or L(+)-glutamine (1 g/40 ml water) was injected into the residual stomach through the gastric tube every 12 h after surgery for 7 days. Changes in the plasma and intestinal intracellular concentration of glutamine and in gastrointestinal motility were measured. The plasma and intracellular glutamine levels decreased after the operation in both groups, although the decreased intracellular glutamine levels were not significantly different than preoperative levels. The glutamine group showed a significantly smaller decrease of the plasma glutamine level compared with the control group (P < 0.05). All the dogs showed gastrointestinal dysmotility after the operation. The mean length of time between the operation and the appearance of interdigestive migrating contractions in the glutamine group was significantly shorter than in the control group (22.4 +/- 3.1 h versus 37.8 +/- 4.0 h, respectively; P < 0.05). In conclusion, glutamine could act as a motility-recovery agent after abdominal surgery and thereby decrease the duration of POI.

Composite Overwrapped Pressure Vessels (COPV) Stress Rupture Test

NASA Technical Reports Server (NTRS)

Russell, Richard; Flynn, Howard; Forth, Scott; Greene, Nathanael; Kezian, Michael; Varanauski, Don; Yoder, Tommy; Woodworth, Warren

2009-01-01

One of the major concerns for the aging Space Shuttle fleet is the stress rupture life of composite overwrapped pressure vessels (COPVs). Stress rupture life of a COPV has been defined as the minimum time during which the composite maintains structural integrity considering the combined effects of stress levels and time. To assist in the evaluation of the aging COPVs in the Orbiter fleet an analytical reliability model was developed. The actual data used to construct this model was from testing of COPVs constructed of similar, but not exactly same materials and pressure cycles as used on Orbiter vessels. Since no actual Orbiter COPV stress rupture data exists the Space Shuttle Program decided to run a stress rupture test to compare to model predictions. Due to availability of spares, the testing was unfortunately limited to one 40" vessel. The stress rupture test was performed at maximum operating pressure at an elevated temperature to accelerate aging. The test was performed in two phases. The first phase, 130 F, a moderately accelerated test designed to achieve the midpoint of the model predicted point reliability. The more aggressive second phase, performed at 160 F was designed to determine if the test article will exceed the 95% confidence interval of the model. This paper will discuss the results of this test, it's implications and possible follow-on testing.

Model for detection and assessment of abiotic stress caused by uranium mining in European Black Pine landscapes

NASA Astrophysics Data System (ADS)

Filchev, Lachezar; Roumenina, Eugenia

2013-10-01

The article presents the results obtained from a study for detection and assessment of abiotic stress through pollution with heavy metals, metalloids, and natural radionuclides in European Black Pine (Pinus nigra L.) forests caused by uranium mining using ground-based biogeochemical, biophysical, and field spectrometry data. The forests are located on a territory subject to underground and open uranium mining. An operational model of the study is proposed. The areas subject to technogeochemical load are outlined based on the aggregate pollution index Zc. Laboratory and field spectrometry data were used to detect the signals of abiotic stress at pixel level. The methods used for determination of stressed and unstressed black pine forests are: four vegetation indices (TCARI, MCARI, MTVI 2, and PRI 1) for stress detection, and the position, depth, asymmetry, and shift of the red-edge. Based on the "blue shift" and the depth and position of the red-edge, registered by the laboratory analysis and field spectral reflectance, it is established that coniferous forests subject to abiotic stress show an increase in total chlorophyll content and carotene. It has been found that the vegetation indices MTVI 2 and PRI 1, as well as the combination of vegetation indices and pigments may be used as a direct indicator of abiotic stress in coniferous forests caused by uranium mining.

Sensor for Direct Measurement of the Boundary Shear Stress in Fluid Flow

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Sherrit, Stewart; Chang, Zensheu; Chen, Beck; Widholm, Scott; Ostlund, Patrick

2011-01-01

The formation of scour patterns at bridge piers is driven by the forces at the boundary of the water flow. In most experimental scour studies, indirect processes have been applied to estimate the shear and normal stress using measured velocity profiles. The estimations are based on theoretical models and associated assumptions. However, the turbulence flow fields and boundary layer in the pier-scour region are very complex. In addition, available turbulence models cannot account accurately for the bed roughness effect. Direct measurement of the boundary shear and normal stress and their fluctuations are attractive alternatives. However, this approach is a challenging one especially for high spatial resolution and high fidelity measurements. The authors designed and fabricated a prototype miniature shear stress sensor including an EDM machined floating plate and a high-resolution laser optical encoder. Tests were performed both in air as well as operation in water with controlled flow. The sensor sensitivity, stability and signal-to-noise level were measured and evaluated. The detailed test results and a discussion of future work will be presented in this paper.

Psychological stress during exercise: immunoendocrine and oxidative responses.

PubMed

Huang, Chun-Jung; Webb, Heather E; Evans, Ronald K; McCleod, Kelly A; Tangsilsat, Supatchara E; Kamimori, Gary H; Acevedo, Edmund O

2010-12-01

The purpose of this study was to examine the changes in catecholamines (epinephrine [EPI] and norepinephrine [NE]), interleukin-2 (IL-2) and a biomarker of oxidative stress (8-isoprostane) in healthy individuals who were exposed to a dual challenge (physical and psychological stress). Furthermore, this study also examined the possible relationships between catecholamines (NE and EPI) and 8-isoprostane and between IL-2 and 8-isoprostane following a combined physical and psychological challenge. Seven healthy male subjects completed two experimental conditions. The exercise-alone condition (EAC) consisted of cycling at 60% VO(2max) for 37 min, while the dual-stress condition (DSC) included 20 min of a mental challenge while cycling. DSC showed greater EPI and 8-isoprostane levels (significant condition by time interaction). NE and IL-2 revealed significant change across time in both conditions. In addition, following dual stress, EPI area-under-the-curve (AUC) demonstrated a positive correlation with NE AUC and IL-2 AUC. NE AUC was positively correlated with IL-2 AUC and peak 8-isoprostane, and peak IL-2 was positively correlated with peak 8-isoprostane in response to a dual stress. The potential explanation for elevated oxidative stress during dual stress may be through the effects of the release of catecholamines and IL-2. These findings may further provide the potential explanation that dual stress alters physiological homeostasis in many occupations including firefighting, military operations and law enforcement. A greater understanding of these responses to stress can assist in finding strategies (e.g. exercise training) to overcome the inherent psychobiological challenges associated with physically and mentally demanding professions.

Contributions of physical and cognitive impairments to self-reported driving difficulty in chronic whiplash-associated disorders.

PubMed

Takasaki, Hiroshi; Treleaven, Julia; Johnston, Venerina; Jull, Gwendolen

2013-08-15

Cross-sectional. To conduct a preliminary analysis of the physical, cognitive, and psychological domains contributing to self-reported driving difficulty after adjusting for neck pain, dizziness, and relevant demographics in chronic whiplash-associated disorders (WAD) using hierarchical regression modeling. Pain is a risk factor for car crashes, and dizziness may affect fitness to drive. Both symptoms are common in chronic WAD and difficulty driving is a common complaint in this group. Chronic WAD is often accompanied by physical, cognitive, and psychological impairments. These impairments may contribute to self-reported driving difficulty beyond neck pain, dizziness, and relevant demographics. Forty individuals with chronic WAD participated. Dependent variables were the magnitude of self-reported driving difficulty assessed in the strategic, tactical, and operational levels of the Neck Pain Driving Index. Three models were developed to assess the contributions of independent variables (physical, cognitive, and psychological domains) to each of the 3 dependent variables after adjusting for neck pain intensity, dizziness, and driving demographics. The measures included were: physical domain-range and maximum speed of head rotation, performances during gaze stability, eye-head coordination, and visual dependency tests; cognitive domain-self-reported cognitive symptoms including fatigue and the trail making tests; and psychological domain-general stress, traumatic stress, depression, and fear of neck movements and driving. Symptom duration was relevant to driving difficulty in the strategic and tactical levels. The cognitive domain increased statistical power to estimate the strategic and operational levels (P < 0.1) beyond other contributors. The physical domain increased statistical power to estimate the tactical level (P < 0.1) beyond other contributors. Physical and cognitive impairments independently contributed to self-reported driving difficulty in chronic WAD beyond neck pain, dizziness, and symptom duration. 3.

Determination of the maximum operating range of hydrodynamic stress in mammalian cell culture.

PubMed

Neunstoecklin, Benjamin; Stettler, Matthieu; Solacroup, Thomas; Broly, Hervé; Morbidelli, Massimo; Soos, Miroslav

2015-01-20

Application of quality by design (QbD) requires identification of the maximum operating range for parameters affecting the cell culture process. These include hydrodynamic stress, mass transfer or gradients in dissolved oxygen and pH. Since most of these are affected by the impeller design and speed, the main goal of this work was to identify a maximum operating range for hydrodynamic stress, where no variation of cell growth, productivity and product quality can be ensured. Two scale-down models were developed operating under laminar and turbulent condition, generating repetitive oscillating hydrodynamic stress with maximum stress values ranging from 0.4 to 420Pa, to compare the effect of the different flow regimes on the cells behavior. Two manufacturing cell lines (CHO and Sp2/0) used for the synthesis of therapeutic proteins were employed in this study. For both cell lines multiple process outputs were used to determine the threshold values of hydrodynamic stress, such as cell growth, morphology, metabolism and productivity. They were found to be different in between the cell lines with values equal to 32.4±4.4Pa and 25.2±2.4Pa for CHO and Sp2/0, respectively. Below the measured thresholds both cell lines do not show any appreciable effect of the hydrodynamic stress on any critical quality attribute, while above, cells responded negatively to the elevated stress. To confirm the applicability of the proposed method, the obtained results were compared with data generated from classical small-scale reactors with a working volume of 3L. Copyright © 2014 Elsevier B.V. All rights reserved.

Stress Analysis of B-52B and B-52H Air-Launching Systems Failure-Critical Structural Components

NASA Technical Reports Server (NTRS)

Ko, William L.

2005-01-01

The operational life analysis of any airborne failure-critical structural component requires the stress-load equation, which relates the applied load to the maximum tangential tensile stress at the critical stress point. The failure-critical structural components identified are the B-52B Pegasus pylon adapter shackles, B-52B Pegasus pylon hooks, B-52H airplane pylon hooks, B-52H airplane front fittings, B-52H airplane rear pylon fitting, and the B-52H airplane pylon lower sway brace. Finite-element stress analysis was performed on the said structural components, and the critical stress point was located and the stress-load equation was established for each failure-critical structural component. The ultimate load, yield load, and proof load needed for operational life analysis were established for each failure-critical structural component.

The effect of post-traumatic-stress-disorder on intra-operative analgesia in a veteran population during cataract procedures carried out using retrobulbar or topical anesthesia: a retrospective study.

PubMed

Rapoport, Yuna; Wayman, Laura L; Chomsky, Amy S

2017-06-07

A growing proportion of veterans treated at the Veterans Health Administration (VA) have a history of post-traumatic-stress-disorder (PTSD), and there exists a higher rate of PTSD amongst veterans than the general population. The purpose of this study is to determine the correlation between PTSD and intra-operative analgesia, intra-operative time, and anesthesia type for cataract surgery in a veteran population. Secondary objectives are to determine if patient age, and first or second eye surgery affect intra-operative pain control or are correlated with type of anesthesia modality. A retrospective study of 330 cataract surgeries performed by resident physicians between January and September 2012 at the Veterans Affairs Medical Center Tennessee Valley Healthcare System, Nashville and Murfreesboro Campuses was completed. Three hundred and thirty veteran patients were selected if their cataract surgery was performed between January and September 2012. Combined cases were excluded. The primary outcome evaluated was intra-operative analgesia. Secondary outcomes included history of post-traumatic-stress-disorder, anesthesia type, first or second eye, pain control, intra-operative heart rate and blood pressure, age, and case complexity. Data was analyzed using an unpaired two-sample Welch's t-test assuming unequal variance and Z test of comparison of proportions. Patients with post-traumatic-stress-disorder reported higher pain scores, had longer operative times, and were more likely to have received a retrobulbar block. Operative time was not associated with an increased pain score, irrespective of anesthesia type, when controlled for PTSD. Complex cases had longer operative times, more sedation, and higher pain scores. P < 0.05 was used consistently. Post-traumatic stress disorder and anxiety are more prevalent in the veteran population. Our data suggests that a history of post-traumatic-stress-disorder was correlated with higher pain scores, longer operative times, and with having received a retrobulbar block. Patients without a history of PTSD were more likely to have received topical anesthesia with or without sedation. The veteran population requires more sedation to allay anxiety and perceptions of discomfort, which may account for longer surgical times. The veteran population is a special population and it is important to investigate how PTSD in the veteran population affects intra-operative analgesia.

Smart built-in test

NASA Technical Reports Server (NTRS)

Richards, Dale W.

1990-01-01

The work which built-in test (BIT) is asked to perform in today's electronic systems increases with every insertion of new technology or introduction of tighter performance criteria. Yet the basic purpose remains unchanged -- to determine with high confidence the operational capability of that equipment. Achievement of this level of BIT performance requires the management and assimilation of a large amount of data, both realtime and historical. Smart BIT has taken advantage of advanced techniques from the field of artificial intelligence (AI) in order to meet these demands. The Smart BIT approach enhances traditional functional BIT by utilizing AI techniques to incorporate environmental stress data, temporal BIT information and maintenance data, and realtime BIT reports into an integrated test methodology for increased BIT effectiveness and confidence levels. Future research in this area will incorporate onboard fault-logging of BIT output, stress data and Smart BIT decision criteria in support of a singular, integrated and complete test and maintenance capability. The state of this research is described along with a discussion of directions for future development.

Smart built-in test

NASA Astrophysics Data System (ADS)

Richards, Dale W.

1990-03-01

The work which built-in test (BIT) is asked to perform in today's electronic systems increases with every insertion of new technology or introduction of tighter performance criteria. Yet the basic purpose remains unchanged -- to determine with high confidence the operational capability of that equipment. Achievement of this level of BIT performance requires the management and assimilation of a large amount of data, both realtime and historical. Smart BIT has taken advantage of advanced techniques from the field of artificial intelligence (AI) in order to meet these demands. The Smart BIT approach enhances traditional functional BIT by utilizing AI techniques to incorporate environmental stress data, temporal BIT information and maintenance data, and realtime BIT reports into an integrated test methodology for increased BIT effectiveness and confidence levels. Future research in this area will incorporate onboard fault-logging of BIT output, stress data and Smart BIT decision criteria in support of a singular, integrated and complete test and maintenance capability. The state of this research is described along with a discussion of directions for future development.

An analysis of post-traumatic stress symptoms in United States Air Force drone operators.

PubMed

Chappelle, Wayne; Goodman, Tanya; Reardon, Laura; Thompson, William

2014-06-01

Remotely piloted aircraft (RPA), commonly referred to as "drones," have emerged over the past decade as an innovative warfighting tool. Given there is a paucity of empirical research assessing drone operators, the purpose of this study was to assess for the prevalence of PTSD symptoms among this cohort. Of the 1084 United States Air Force (USAF) drone operators that participated, a total of 4.3% endorsed a pattern of symptoms of moderate to extreme level of severity meeting criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders-4th edition. The incidence of PTSD among USAF drone operators in this study was lower than rates of PTSD (10-18%) among military personnel returning from deployment but higher than incidence rates (less than 1%) of USAF drone operators reported in electronic medical records. Although low PTSD rates may be promising, limitations to this study are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Stress and academic performance among medical students.

PubMed

Sohail, Nudrat

2013-01-01

To determine the relationship of stress and academic performance in first year medical students and to identify sources of stress, levels of stress and relevant coping strategies. Mixed method sequential. Allama Iqbal Medical College, Lahore, from March to December 2010. Survey questionnaire and in-depth interviews were carried out in the first year students with their consent. Two hundred and fifty students were surveyed, out of whom 120 students responded. Twelve students with their consent were interviewed. Non-probability purposive sampling was employed for both types of data collection. SPSS version 20 was used. The qualitative data generated through structured in-depth interviews, were analyzed by content analysis. Low level of stress was found in 7.5% (score ‹150), moderate level of stress was present in 71.67% (score between 150 and 300), and high level of stress was observed in 20.83% (score ›300) of the students. There is moderate negative (-0.583) and significant (p < 0.01) correlation between academic performance and sources of stress. Similarly there is moderate negative (-0.478) and significant (p < 0.01) correlation between academic performance and levels of stress. There was strong positive (0.799) and significant (p < 0.01), correlation between stress level and number of stress sources. The study showed a diversity of stress sources and a high level of stress in the medical students. The results also show that higher level of stress is associated with poor academic performance.

JIP3 deficiency attenuates cardiac hypertrophy by suppression of JNK pathway.

PubMed

Ma, Qinghua; Liu, Yuxiu; Chen, Lianghua

2018-06-15

Pathological cardiac hypertrophy is a leading cause of morbidity and mortality worldwide; however, our understanding of the molecular mechanisms revealing the disease is still unclear. In the present study, we suggested that c-Jun N-terminal kinase (JNK)-interacting protein 3 (JIP3), involved in various cellular processes, played an essential role in regulating pathological cardiac hypertrophy through in vivo and in vitro studies. JIP3 was highly expressed in human hearts with hypertrophic cardiomyopathy (HCM), and in mouse hypertrophic hearts. Following, the wild type (WT) and JIP3-knockout (KO) mice subjected to aortic banding (AB) challenge were used as animal models with cardiac hypertrophy. The results showed that JIP3-KO mice after AB operation exhibited attenuated cardiac function, reduced fibrosis levels and decreased hypertrophic marker proteins, including atrial natriuretic peptides (Anp) and brain/B-type natriuretic peptides (Bnp) and β-myosin heavy chain (β-Mhc). Loss of JIP3 also ameliorated oxidative stress, inflammatory response, apoptosis and endoplasmic reticulum (ER) stress in hearts of mice after AB surgery. Consistently, the expressions of ER stress-related molecules, such as phosphorylated-α-subunit of the eukaryotic initiation factor-2 (eIF2α), glucose-regulated protein (GRP) 78 and C/-EBP homologous protein (CHOP), were markedly decreased by JIP3-deficiency in hearts of AB-operated mice. JNK and its down-streaming signal of p90rsk was highly activated by AB operation in WT mice, while being significantly reversed by JIP3-ablation. Intriguingly, the in vitro results showed that promoting JNK activation by using its activator of anisomycin enhanced AngII-stimulated ER stress, oxidative stress, apoptosis and inflammatory response in cardiomyocytes isolated from WT mice. However, JIP3-KO-attenuated these pathologies was rescued by anisomycin treatment in AngII-incubated cardiomyocytes. Together, the findings indicated that blockage of JIP3 could alleviate cardiac hypertrophy via inactivating JNK pathway, and thus might be a promising strategy to prevent pathological cardiac hypertrophy. Copyright © 2018. Published by Elsevier Inc.

Extended Life PZT Stack Test Fixture

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Sherrit, S.; Bao, X.; Aldrich, J.; Bar-Cohen, Y.; Jones, C.

2009-01-01

Piezoelectric stacks are being sought to be used as actuators for precision positioning and deployment of mechanisms in future planetary missions. Beside the requirement for very high operation reliability, these actuators are required for operation at space environments that are considered harsh compared to normal terrestrial conditions.These environmental conditions include low and high temperatures and vacuum or high pressure. Additionally, the stacks are subjected to high stress and in some applications need to operate with a very long lifetime durability.Many of these requirements are beyond the current industry design margins for nominal terrestrial applications. In order to investigate some of the properties that will indicate the durability of such actuators and their limitations we have developed a new type of test fixture that can be easily integrated in various test chambers for simulating environmental conditions, can provide access for multiple measurements while being exposed to adjustable stress levels. We designed and built two test fixtures and these fixtures were made to be adjustable for testing stacks with different dimensions and can be easily used in small or large numbers. The properties that were measured using these fixtures include impedance, capacitance, dielectric loss factor, leakage current, displacement, breakdown voltage, and lifetime performance. The fixtures characteristics and the test capabilities are presented in this paper.

Orientation dependence of the stress rupture properties of Nickel-base superalloy single crystals

NASA Technical Reports Server (NTRS)

Mackay, R. A.

1981-01-01

The influence of orientation of the stress rupture behavior of Mar-M247 single crystals was studied. Stress rupture tests were performed at 724 MPa and 774 C where the effect of anisotropy is prominent. The mechanical behavior of the single crystals was rationalized on the basis of the Schmid factors for the operative slip systems and the lattice rotations which the crystals underwent during deformation. The stress rupture lives were found to be greatly influenced by the lattice rotations required to produce intersecting slip, because steady-state creep does not begin until after the onset of intersecting slip. Crystals which required large rotations to become oriented for intersecting slip exhibited a large primary creep strain, a large effective stress level at the onset of steady-state creep, and consequently a short stress rupture life. A unified analysis was attained for the stress rupture behavior of the Mar-M247 single crystals tested in this study at 774 C and that of the Mar-M200 single crystals tested in a prior study at 760 C. In this analysis, the standard 001-011-111 stereographic triangle was divided into several regions of crystallographic orientation which were rank ordered according to stress rupture life for this temperature regime. This plot indicates that those crystals having orientations within about 25 deg of the 001 exhibited significantly longer lives when their orientations were closer to the 001-011 boundary of the stereographic triangle than to the 001-111 boundary.

An Analysis of Post-Traumatic Stress Symptoms in United States Air Force Drone Operators

DTIC Science & Technology

2014-05-17

war-time imagery (i.e., potential traumatic events). Ouma, Chappelle, and Salinas (2011) investigated self- reported stress and burnout among 296 USAF...related directly to operational factors (e.g., long work hours, disruptive shift schedules, daily balance of warfighter with domestic duties). Mental...Journal Article 3. DATES COVERED (From – To) Jan 2012 – Dec 2012 4. TITLE AND SUBTITLE An analysis of post-traumatic stress symptoms in United

Perceived stress and fatigue among students in a doctor of chiropractic training program.

PubMed

Kizhakkeveettil, Anupama; Vosko, Andrew M; Brash, Marissa; Ph, Dr; Philips, Michael A

2017-03-01

High levels of stress and fatigue are associated with decreased academic success, well-being, and quality of life. The objective of this research was to quantify levels of perceived stress and fatigue among chiropractic students to identify sources of and student coping mechanisms for perceived stress and fatigue and to identify the relationship between students' perceived stress and fatigue. A survey comprised of the Perceived Stress Scale, the Undergraduate Sources of Stress Survey, and the Piper Fatigue Scale was administered to chiropractic students in their 2nd, 5th, and 8th trimesters of doctoral study. Data were analyzed by descriptive statistics, 1-way analysis of variance, and linear correlation tests. Students reported having moderate to high levels of stress and fatigue, with higher levels of stress and fatigue seen in women than in men. A nonsignificant difference among stress scores and a significant difference among fatigue scores were observed based on program term. Levels of stress predicted levels of fatigue, and stress was strongly correlated with psychological health, relationships with family members, mood, and need for learning accommodations. Fatigue was strongly correlated with psychological health, academic demands, and conflicts between studies and other activities. There are differences in the reporting of perceived stress and fatigue levels in this chiropractic student population based on gender. The correlation between fatigue and stress also suggests that measures that may alleviate one may likely affect the other.

Conceptual framework and trend analysis of water-level responses to hydrologic stresses, Pahute Mesa–Oasis Valley groundwater basin, Nevada, 1966-2016

USGS Publications Warehouse

Jackson, Tracie R.; Fenelon, Joseph M.

2018-05-31

This report identifies water-level trends in wells and provides a conceptual framework that explains the hydrologic stresses and factors causing the trends in the Pahute Mesa–Oasis Valley (PMOV) groundwater basin, southern Nevada. Water levels in 79 wells were analyzed for trends between 1966 and 2016. The magnitude and duration of water-level responses to hydrologic stresses were analyzed graphically, statistically, and with water-level models.The conceptual framework consists of multiple stress-specific conceptual models to explain water-level responses to the following hydrologic stresses: recharge, evapotranspiration, pumping, nuclear testing, and wellbore equilibration. Dominant hydrologic stresses affecting water-level trends in each well were used to categorize trends as nonstatic, transient, or steady state.The conceptual framework of water-level responses to hydrologic stresses and trend analyses provide a comprehensive understanding of the PMOV basin and vicinity. The trend analysis links water-level fluctuations in wells to hydrologic stresses and potential factors causing the trends. Transient and steady-state trend categorizations can be used to determine the appropriate water-level data for groundwater studies.

Method of preparing a two-way shape memory alloy

DOEpatents

Johnson, Alfred D.

1984-01-01

A two-way shape memory alloy, a method of training a shape memory alloy, and a heat engine employing the two-way shape memory alloy to do external work during both heating and cooling phases. The alloy is heated under a first training stress to a temperature which is above the upper operating temperature of the alloy, then cooled to a cold temperature below the zero-force transition temperature of the alloy, then deformed while applying a second training stress which is greater in magnitude than the stress at which the alloy is to be operated, then heated back to the hot temperature, changing from the second training stress back to the first training stress.

[Phenomenon of preoperative stress in patients with ischemic heart disease. Assessment of its clinical and prognostic significance].

PubMed

Barbarash, O L; Shabalina, L V; Bergen, E I; Guliaeva, E N; Barbarash, N A

1998-01-01

To assess preoperative stress in patients with ischemic heart disease (IHD) and its influence on the course of early intraoperative period. 79 patients scheduled for aortocoronary bypass operation were studied to assess the phenomenon of preoperative psychoemotional stress (clinical characteristics, personal anxiety, humoral and vegetative regulation. 24 hours before operation IHD patients became anxious, coronary insufficiency and arrhythmia aggravated as shown by Holter ECG monitoring. Initial insufficiency of the antioxidant system, disturbances of the platelet-vascular hemostasis, hyperlipidemia and dyslipoproteinemia enhanced. Preoperative changes due to stress reaction affected the course of early intraoperative period. It is necessary to apply individual schemes of stress-limiting preoperative preparation in IHD patients.

Vacuum quantum stress tensor fluctuations: A diagonalization approach

NASA Astrophysics Data System (ADS)

Schiappacasse, Enrico D.; Fewster, Christopher J.; Ford, L. H.

2018-01-01

Large vacuum fluctuations of a quantum stress tensor can be described by the asymptotic behavior of its probability distribution. Here we focus on stress tensor operators which have been averaged with a sampling function in time. The Minkowski vacuum state is not an eigenstate of the time-averaged operator, but can be expanded in terms of its eigenstates. We calculate the probability distribution and the cumulative probability distribution for obtaining a given value in a measurement of the time-averaged operator taken in the vacuum state. In these calculations, we study a specific operator that contributes to the stress-energy tensor of a massless scalar field in Minkowski spacetime, namely, the normal ordered square of the time derivative of the field. We analyze the rate of decrease of the tail of the probability distribution for different temporal sampling functions, such as compactly supported functions and the Lorentzian function. We find that the tails decrease relatively slowly, as exponentials of fractional powers, in agreement with previous work using the moments of the distribution. Our results lend additional support to the conclusion that large vacuum stress tensor fluctuations are more probable than large thermal fluctuations, and may have observable effects.

Whole-body vibration exposure in subway cars and review of adverse health effects.

PubMed

Johanning, E; Wilder, D G; Landrigan, P J; Pope, M H

1991-05-01

New York City Transit Authority subway operators have a high prevalence of back problems. To evaluate a possible dose-response relationship for whole-body vibration, we studied subway car vibrations measured and analyzed according to the International Standard Organization 2631 and Verein Deutscher Ingenieure 2057 standards. Vibration transducers in triaxial orientation were mounted in a disc pad directly on the subway operator's seat. The relatively high lateral and vertical accelerations, primarily the combined effects, may all contribute to the high rate of musculoskeletal complaints, especially of the lower back. Other factors aggravating whole-body vibrations include primitive ergonomic cab and seat design, forced body posture, high noise levels, and organizational work stress.

Finite element analysis of heat load of tungsten relevant to ITER conditions

NASA Astrophysics Data System (ADS)

Zinovev, A.; Terentyev, D.; Delannay, L.

2017-12-01

A computational procedure is proposed in order to predict the initiation of intergranular cracks in tungsten with ITER specification microstructure (i.e. characterised by elongated micrometre-sized grains). Damage is caused by a cyclic heat load, which emerges from plasma instabilities during operation of thermonuclear devices. First, a macroscopic thermo-mechanical simulation is performed in order to obtain temperature- and strain field in the material. The strain path is recorded at a selected point of interest of the macroscopic specimen, and is then applied at the microscopic level to a finite element mesh of a polycrystal. In the microscopic simulation, the stress state at the grain boundaries serves as the marker of cracking initiation. The simulated heat load cycle is a representative of edge-localized modes, which are anticipated during normal operations of ITER. Normal stresses at the grain boundary interfaces were shown to strongly depend on the direction of grain orientation with respect to the heat flux direction and to attain higher values if the flux is perpendicular to the elongated grains, where it apparently promotes crack initiation.

Design and modeling of an efficiency horizontal thermal micro-actuator with integrated piezoresistors for precise control.

PubMed

Zhang, Yan; Lee, Dong-Weon

2010-05-01

An integrated system made up of a double-hot arm electro-thermal microactuator and a piezoresistor embedded at the base of the 'cold arm' is proposed. The electro-thermo-mechanical modeling and optimization is developed to elaborate the operation mechanism of the hybrid system through numerical simulations. For given materials, the geometry design mostly influences the performance of the sensor and actuator, which can be considered separately. That is because thermal expansion induced heating energy has less influence on the base area of the 'cold arm,' where is the maximum stress. The piezoresistor is positioned here for large sensitivity to monitor the in-plane movement of the system and characterize the actuator response precisely in real time. Force method is used to analyze the thermal induced mechanical expansion in the redundant structure. On the other hand, the integrated actuating mechanism is designed for high speed imaging. Based on the simulation results, the actuator operates at levels below 5 mA appearing to be very reliable, and the stress sensitivity is about 40 MPa per micron.

Elevated ventricular wall stress disrupts cardiomyocyte t-tubule structure and calcium homeostasis.

PubMed

Frisk, Michael; Ruud, Marianne; Espe, Emil K S; Aronsen, Jan Magnus; Røe, Åsmund T; Zhang, Lili; Norseng, Per Andreas; Sejersted, Ole M; Christensen, Geir A; Sjaastad, Ivar; Louch, William E

2016-10-01

Invaginations of the cellular membrane called t-tubules are essential for maintaining efficient excitation-contraction coupling in ventricular cardiomyocytes. Disruption of t-tubule structure during heart failure has been linked to dyssynchronous, slowed Ca(2+) release and reduced power of the heartbeat. The underlying mechanism is, however, unknown. We presently investigated whether elevated ventricular wall stress triggers remodelling of t-tubule structure and function. MRI and blood pressure measurements were employed to examine regional wall stress across the left ventricle of sham-operated and failing, post-infarction rat hearts. In failing hearts, elevated left ventricular diastolic pressure and ventricular dilation resulted in markedly increased wall stress, particularly in the thin-walled region proximal to the infarct. High wall stress in this proximal zone was associated with reduced expression of the dyadic anchor junctophilin-2 and disrupted cardiomyocyte t-tubular structure. Indeed, local wall stress measurements predicted t-tubule density across sham and failing hearts. Elevated wall stress and disrupted cardiomyocyte structure in the proximal zone were also associated with desynchronized Ca(2+) release in cardiomyocytes and markedly reduced local contractility in vivo. A causative role of wall stress in promoting t-tubule remodelling was established by applying stretch to papillary muscles ex vivo under culture conditions. Loads comparable to wall stress levels observed in vivo in the proximal zone reduced expression of junctophilin-2 and promoted t-tubule loss. Elevated wall stress reduces junctophilin-2 expression and disrupts t-tubule integrity, Ca(2+) release, and contractile function. These findings provide new insight into the role of wall stress in promoting heart failure progression. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.

Interindividual differences in stress sensitivity: basal and stress-induced cortisol levels differentially predict neural vigilance processing under stress

PubMed Central

Klumpers, Floris; Everaerd, Daphne; Kooijman, Sabine C.; van Wingen, Guido A.; Fernández, Guillén

2016-01-01

Stress exposure is known to precipitate psychological disorders. However, large differences exist in how individuals respond to stressful situations. A major marker for stress sensitivity is hypothalamus–pituitary–adrenal (HPA)-axis function. Here, we studied how interindividual variance in both basal cortisol levels and stress-induced cortisol responses predicts differences in neural vigilance processing during stress exposure. Implementing a randomized, counterbalanced, crossover design, 120 healthy male participants were exposed to a stress-induction and control procedure, followed by an emotional perception task (viewing fearful and happy faces) during fMRI scanning. Stress sensitivity was assessed using physiological (salivary cortisol levels) and psychological measures (trait questionnaires). High stress-induced cortisol responses were associated with increased stress sensitivity as assessed by psychological questionnaires, a stronger stress-induced increase in medial temporal activity and greater differential amygdala responses to fearful as opposed to happy faces under control conditions. In contrast, high basal cortisol levels were related to relative stress resilience as reflected by higher extraversion scores, a lower stress-induced increase in amygdala activity and enhanced differential processing of fearful compared with happy faces under stress. These findings seem to reflect a critical role for HPA-axis signaling in stress coping; higher basal levels indicate stress resilience, whereas higher cortisol responsivity to stress might facilitate recovery in those individuals prone to react sensitively to stress. PMID:26668010

Postoperative plasma 8-iso-prostaglandin F2α levels are associated with delirium and cognitive dysfunction in elderly patients after hip fracture surgery.

PubMed

Zheng, Yuan-Bo; Ruan, Guo-Mo; Fu, Jia-Xing; Su, Zhong-Liang; Cheng, Peng; Lu, Jian-Zuo

2016-04-01

Oxidative stress may be involved in occurrence of postoperative delirium (POD) and cognitive dysfunction (POCD). 8-iso-Prostaglandin F2α (8-iso-PGF2α), an isoprostane derived from arachidonic acid via lipid peroxidation, is considered a gold standard for measuring oxidative stress. The present study aimed to investigate the ability of postoperative plasma 8-iso-PGF2α levels to predict POD and POCD in elderly patients undergoing hip fracture surgery. Postoperative plasma 8-iso-PGF2α levels of 182 patients were measured by an enzyme-linked immunosorbent assay. We assessed the relationships between plasma 8-iso-PGF2α levels and the risk of POD and POCD using a multivariate analysis. Plasma 8-iso-PGF2α levels and age were identified as the independent predictors for POD and POCD. Based on areas under receiver operating characteristic curve, the predictive values of 8-iso-PGF2α were obviously higher than those of age for POD and POCD. In a combined logistic-regression model, 8-iso-PGF2α significantly enhanced the areas under curve of age for prediction of POD and POCD. Postoperative plasma 8-iso-PGF2α levels may have the potential to predict POD and POCD in elder patients undergoing hip fracture surgery. Copyright © 2016 Elsevier B.V. All rights reserved.

Prevalence of Posttraumatic Stress Disorder in Remotely Piloted Aircraft Operators in the United States Air Force

DTIC Science & Technology

2016-05-24

common feature of the depressive and anxiety disorders: a test of the revised integrative hierarchical model in a national sample. J Abnorm Psychol...proliferation of this unique form of warfare, concerns have been raised regarding the psychological impact such operations have on RPA operators directly...and clinical interviews utilizing the Clinician Administered Psychological Survey to determine the nature of the respondents’ stressful military

An empirical examination of the impacts of decentralized nursing unit design.

PubMed

Pati, Debajyoti; Harvey, Thomas E; Redden, Pamela; Summers, Barbara; Pati, Sipra

2015-01-01

The objective of the study was to examine the impact of decentralization on operational efficiency, staff well-being, and teamwork on three inpatient units. Decentralized unit operations and the corresponding physical design solution were hypothesized to positively affect several concerns-productive use of nursing time, staff stress, walking distances, and teamwork, among others. With a wide adoption of the concept, empirical evidence on the impact of decentralization was warranted. A multimethod, before-and-after, quasi-experimental design was adopted for the study, focusing on five issues, namely, (1) how nurses spend their time, (2) walking distance, (3) acute stress, (4) productivity, and (5) teamwork. Data on all five issues were collected on three older units with centralized operational model (before move). The same set of data, with identical tools and measures, were collected on the same units after move in to new physical units with decentralized operational model. Data were collected during spring and fall of 2011. Documentation, nurse station use, medication room use, and supplies room use showed consistent change across the three units. Walking distance increased (statistically significant) on two of the three units. Self-reported level of collaboration decreased, although assessment of the physical facility for collaboration increased. Decentralized nursing and physical design models potentially result in quality of work improvements associated with documentation, medication, and supplies. However, there are unexpected consequences associated with walking, and staff collaboration and teamwork. The solution to the unexpected consequences may lie in operational interventions and greater emphasis on culture change. © The Author(s) 2015.

Opioid modulation of reflex versus operant responses following stress in the rat.

PubMed

King, C D; Devine, D P; Vierck, C J; Mauderli, A; Yezierski, R P

2007-06-15

In pre-clinical models intended to evaluate nociceptive processing, acute stress suppresses reflex responses to thermal stimulation, an effect previously described as stress-induced "analgesia." Suggestions that endogenous opioids mediate this effect are based on demonstrations that stress-induced hyporeflexia is enhanced by high dose morphine (>5 mg/kg) and is reversed by naloxone. However, reflexes and pain sensations can be modulated differentially. Therefore, in the present study direct comparisons were made of opioid agonist and antagonist actions, independently and in combination with acute restraint stress in Long Evans rats, on reflex lick-guard (L/G) and operant escape responses to nociceptive thermal stimulation (44.5 degrees C). A high dose of morphine (>8 mg/kg) was required to reduce reflex responding, but a moderate dose of morphine (1 mg/kg) significantly reduced escape responding. The same moderate dose (and also 5 mg/kg) of morphine significantly enhanced reflex responding. Naloxone (3 mg/kg) significantly enhanced escape responding but did not affect L/G responding. Restraint stress significantly suppressed L/G reflexes (hyporeflexia) but enhanced escape responses (hyperalgesia). Stress-induced hyperalgesia was significantly reduced by morphine and enhanced by naloxone. In contrast, stress-induced hyporeflexia was blocked by both naloxone and 1 mg/kg of morphine. Thus, stress-induced hyperalgesia was opposed by endogenous opioid release and by administration of morphine. Stress-induced hyporeflexia was dependent upon endogenous opioid release but was counteracted by a moderate dose of morphine. These data demonstrate a differential modulation of reflex and operant outcome measures by stress and by separate or combined opioid antagonism or administration of morphine.

The postoperative cortisol stress response following transsphenoidal pituitary surgery: a potential screening method for assessing preserved pituitary function.

PubMed

Zada, Gabriel; Tirosh, Amir; Huang, Abel P; Laws, Edward R; Woodmansee, Whitney W

2013-09-01

The ability to reliably identify patients with new hypocortisolemia acutely following pituitary surgery is critical. We aimed to quantify the postoperative cortisol stress response following selective transsphenoidal adenomectomy, as a marker for postoperative preservation of functional pituitary gland. Records of 208 patients undergoing transsphenoidal operations for pituitary lesions were reviewed. Patients with Cushing's Disease, preoperative adrenal insufficiency, and those receiving intraoperative steroids were excluded. To quantify the postoperative stress response, the ∆ cortisol index was defined as the postoperative day (POD) 1 morning cortisol minus the preoperative morning cortisol level. The incidence of new hypocortisolemia requiring glucocorticoid replacement upon hospital discharge was also recorded. Fifty-two patients met inclusion criteria. The mean preoperative, POD1, and POD2 cortisol levels were 16.5, 29.2, and 21.8 μg/dL, respectively. Morning fasting cortisol levels on POD1 ranged from 4.2 to 73.0 μg/dL. The ∆ cortisol index ranged from -19.0 to +56.2 (mean +12.7 μg/dL). Five patients (9.6%) developed new hypocortisolemia on POD 1-3 requiring glucocorticoid replacement; only one required long-term replacement. The mean ∆ cortisol in patients requiring postoperative glucocorticoids was -2.8 μg/dL, compared with +14.4 μg/dL in patients without evidence of adrenal insufficiency (p = 0.005). Of the 32 patients (61.5%) with a ∆cortisol >25 μg/dL, none developed postoperative adrenal insufficiency. The postoperative cortisol stress response, as quantified by the ∆ cortisol index, holds potential as a novel and complimentary screening method to predict preservation of normal pituitary function and acute development of new ACTH deficiency following transsphenoidal pituitary surgery.

Kupffer cell ablation attenuates cyclooxygenase-2 expression after trauma and sepsis.

PubMed

Keller, Steve A; Paxian, Marcus; Lee, Sun M; Clemens, Mark G; Huynh, Toan

2005-03-01

Prostaglandins, synthesized by cyclooxygenase (COX), play an important role in the pathophysiology of inflammation. Severe injuries result in immunosuppression, mediated, in part, by maladaptive changes in macrophages. Herein, we assessed Kupffer cell-mediated cyclooxygenase-2 (COX-2) expression on liver function and damage after trauma and sepsis. To ablate Kupffer cells, Sprague Dawley rats were treated with gadolinium chloride (GdCl3) 48 and 24 h before experimentation. Animals then underwent femur fracture (FFx) followed 48 h later by cecal ligation and puncture (CLP). Controls received sham operations. After 24 h, liver samples were obtained, and mRNA and protein expression were determined by PCR, Western blot, and immunohistochemistry. Indocyanine-Green (ICG) clearance and plasma alanine aminotransferase (ALT) levels were determined to assess liver function and damage, respectively. One-way analysis of variance (ANOVA) with Student-Newman-Keuls test was used to assess statistical significance. After CLP alone, FFx+CLP, and GdCl3+FFx+CLP, clearance of ICG decreased. Plasma ALT levels increased in parallel with severity of injury. Kupffer cell depletion attenuated the increased ALT levels after FFx+CLP. Femur fracture alone did not alter COX-2 protein compared with sham. By contrast, COX-2 protein increased after CLP and was potentiated by sequential stress. Again, Kupffer cell depletion abrogated the increase in COX-2 after sequential stress. Immunohistochemical data confirmed COX-2 positive cells to be Kupffer cells. In this study, sequential stress increased hepatic COX-2 protein. Depletion of Kupffer cells reduced COX-2 and attenuated hepatocellular injuries. Our data suggest that Kupffer cell-dependent pathways may contribute to the inflammatory response leading to increased mortality after sequential stress.

Risk factors for DSM-5 posttraumatic stress symptoms (PTSS) among Israeli civilians during the 2014 Israel-Hamas war.

PubMed

Gil, Sharon; Weinberg, Michael; Shamai, Michal; Ron, Pnina; Harel, Hila; Or-Chen, Keren

2016-01-01

In light of current modifications in the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnostic criteria for posttraumatic stress disorder (PTSD), this study aimed to revalidate well-known PTSD risk factors related to terrorism and war in Israel, namely, proximity to the Gaza Strip, dissociative symptoms, acute stress disorder (ASD) symptoms, and social support. One hundred and sixty Israeli civilians were assessed during the 2014 Israel-Hamas war at 2 time points: 1 week after the beginning of the operation (t1) and 1 month after initial evaluation (t2), using the DSM-5 PTSD Symptom Levels Scale (PSLS; Gil, Weinberg, Or-Chen, & Harel, 2015). A paired t test analysis showed significant reduction in the respondents' posttraumatic stress symptoms (PTSS) 1 month after the initial assessment point. A structural equation model (SEM) showed that higher ASD symptoms at t1 and higher dissociative symptoms at t2 increased the risk for PTSS at t2. Conversely, higher peritraumatic dissociation at t1 decreased the risk for PTSS at t2. Proximity to the Gaza Strip, and social support, failed to demonstrate significant association with PTSS at t2. DSM-5 PTSS 1 month after prolonged traumatic exposure are strongly associated with high ASD symptoms at 1 week as a risk factor; high levels of peritraumatic dissociation at 1 week as a protective factor; and high levels of dissociative symptoms at 1 month as a risk factor. Theoretically and clinically the findings of the study further suggest that ongoing massive terrorism and war cannot be viewed or treated as identical to other traumas. (c) 2016 APA, all rights reserved).

Physicians' occupational stress, depressive symptoms and work ability in relation to their working environment: a cross-sectional study of differences among medical residents with various specialties working in German hospitals

PubMed Central

Bernburg, Monika; Vitzthum, Karin; Groneberg, David A; Mache, Stefanie

2016-01-01

Objectives This study aimed to analyse and compare differences in occupational stress, depressive symptoms, work ability and working environment among residents working in various medical specialties. Methods 435 German hospital residents in medical training working in 6 different medical specialties participated in a cross-sectional survey study. Physicians were asked about their working conditions and aspects of mental health and work ability. The Copenhagen Psychosocial Questionnaire, the Work Ability Index, the ICD-10 Symptom Rating and the Perceived Stress Questionnaire were used to measure working conditions, mental health and work ability. Results Results show that up to 17% of the physicians reported high levels of occupational distress and 9% reported high levels of depressive symptoms. 11% of the hospital physicians scored low in work ability. Significant differences between medical specialties were demonstrated for occupational distress, depressive symptoms, work ability, job demands and job resources. Surgeons showed consistently the highest levels of perceived distress but also the highest levels of work ability and lowest scores for depression. Depressive symptoms were rated with the highest levels by anaesthesiologists. Significant associations between physicians’ working conditions, occupational distress and mental health-related aspects are illustrated. Conclusions Study results demonstrated significant differences in specific job stressors, demands and resources. Relevant relations between work factors and physicians' health and work ability are discussed. These findings should be reinvestigated in further studies, especially with a longitudinal study design. This work suggests that to ensure physicians' health, hospital management should plan and implement suitable mental health promotion strategies. In addition, operational efficiency through resource planning optimisation and work process improvements should be focused by hospital management. PMID:27311909

Level of Work Related Stress among Teachers in Elementary Schools.

PubMed

Agai-Demjaha, Teuta; Bislimovska, Jovanka Karadzinska; Mijakoski, Dragan

2015-09-15

Teaching is considered a highly stressful occupation, with work-related stress levels among teachers being among the highest compared to other professions. Unfortunately there are very few studies regarding the levels of work-related stress among teachers in the Republic of Macedonia. To identify the level of self-perceived work-related stress among teachers in elementary schools and its relationship to gender, age, position in the workplace, the level of education and working experience. We performed a descriptive-analytical model of a cross-sectional study that involved 300 teachers employed in nine elementary schools. Evaluation of examined subjects included completion of a specially designed questionnaire. We found that the majority of interviewed teachers perceive their work-related stress as moderate. The level of work-related stress was significantly high related to the gender, age, position in workplace, as well as working experience (p < 0.01), while it was significant related to level of education (p < 0.05). Significantly greater number of lower-grade teachers perceives the workplace as extremely stressful as compared to the upper-grade teachers (18.5% vs. 5.45%), while the same is true for female respondents as compared to the male ones (15.38% vs. 3.8%). In addition, our results show that teachers with university education significantly more often associate their workplace with stronger stress than their colleagues with high education (13.48% vs. 9.4%). We also found that there is no significant difference of stress levels between new and more experienced teachers. Our findings confirm that the majority of interviewed teachers perceived their work-related stress as high or very high. In terms of the relationship between the level of teachers' stress and certain demographic and job characteristics, according to our results, the level of work-related stress has shown significantly high relation to gender, age, levels of grades taught as well as working experience, and significant relation to the level of education.

Level of Work Related Stress among Teachers in Elementary Schools

PubMed Central

Agai–Demjaha, Teuta; Bislimovska, Jovanka Karadzinska; Mijakoski, Dragan

2015-01-01

BACKGROUND: Teaching is considered a highly stressful occupation, with work-related stress levels among teachers being among the highest compared to other professions. Unfortunately there are very few studies regarding the levels of work-related stress among teachers in the Republic of Macedonia. AIM: To identify the level of self-perceived work-related stress among teachers in elementary schools and its relationship to gender, age, position in the workplace, the level of education and working experience. MATERIAL AND METHODS: We performed a descriptive-analytical model of a cross-sectional study that involved 300 teachers employed in nine elementary schools. Evaluation of examined subjects included completion of a specially designed questionnaire. RESULTS: We found that the majority of interviewed teachers perceive their work-related stress as moderate. The level of work-related stress was significantly high related to the gender, age, position in workplace, as well as working experience (p < 0.01), while it was significant related to level of education (p < 0.05). Significantly greater number of lower-grade teachers perceives the workplace as extremely stressful as compared to the upper-grade teachers (18.5% vs. 5.45%), while the same is true for female respondents as compared to the male ones (15.38% vs. 3.8%). In addition, our results show that teachers with university education significantly more often associate their workplace with stronger stress than their colleagues with high education (13.48% vs. 9.4%). We also found that there is no significant difference of stress levels between new and more experienced teachers. CONCLUSION: Our findings confirm that the majority of interviewed teachers perceived their work-related stress as high or very high. In terms of the relationship between the level of teachers’ stress and certain demographic and job characteristics, according to our results, the level of work-related stress has shown significantly high relation to gender, age, levels of grades taught as well as working experience, and significant relation to the level of education. PMID:27275275

Environmental Test Screening Procedure

NASA Technical Reports Server (NTRS)

Zeidler, Janet

2000-01-01

This procedure describes the methods to be used for environmental stress screening (ESS) of the Lightning Mapper Sensor (LMS) lens assembly. Unless otherwise specified, the procedures shall be completed in the order listed, prior to performance of the Acceptance Test Procedure (ATP). The first unit, S/N 001, will be subjected to the Qualification Vibration Levels, while the remainder will be tested at the Operational Level. Prior to ESS, all units will undergo Pre-ESS Functional Testing that includes measuring the on-axis and plus or minus 0.95 full field Modulation Transfer Function and Back Focal Length. Next, all units will undergo ESS testing, and then Acceptance testing per PR 460.

14 CFR 23.907 - Propeller vibration and fatigue.

Code of Federal Regulations, 2010 CFR

2010-01-01

... stresses or loads, including any stress peaks and resonant conditions, throughout the operational envelope of the airplane by either: (1) Measurement of stresses or loads through direct testing or analysis...

14 CFR 23.907 - Propeller vibration and fatigue.

Code of Federal Regulations, 2012 CFR

2012-01-01

... stresses or loads, including any stress peaks and resonant conditions, throughout the operational envelope of the airplane by either: (1) Measurement of stresses or loads through direct testing or analysis...

14 CFR 23.907 - Propeller vibration and fatigue.

Code of Federal Regulations, 2011 CFR

2011-01-01

... stresses or loads, including any stress peaks and resonant conditions, throughout the operational envelope of the airplane by either: (1) Measurement of stresses or loads through direct testing or analysis...

Radiographic Evaluation of Ankle Joint Stability After Calcaneofibular Ligament Elevation During Open Reduction and Internal Fixation of Calcaneus Fracture.

PubMed

Wang, Chien-Shun; Tzeng, Yun-Hsuan; Lin, Chun-Cheng; Huang, Ching-Kuei; Chang, Ming-Chau; Chiang, Chao-Ching

2016-09-01

The aim of this prospective study was to evaluate the influence of sectioning the calcaneofibular ligament (CFL) during an extensile lateral approach during open reduction and internal fixation (ORIF) of calcaneal fractures on ankle joint stability. Forty-two patients with calcaneal fractures that received ORIF were included. Talar tilt stress and anterior drawer radiographs were performed on the operative and contralateral ankles 6 months postoperatively. The average degree of talar tilt on stress radiographs was 3.4 degrees (range, 0-12 degrees) on the operative side and 3.2 degrees (range, 0-14 degrees) on the contralateral side. The mean anterior drawer on stress radiographs of the CFL incised ankle was 6.1 mm (range, 2.4-11.8 mm) and on the contralateral ankle was 5.7 mm (range, 2.6-8.6 mm). There was no statistically significant difference of talar tilt and anterior drawer between the CFL incised side and the contralateral side (P = .658 and .302, respectively). The results suggest that sectioning of the CFL without any repair during ORIF of a calcaneal fracture does not have a negative effect on stability of the ankle. Repair of the CFL is, thus, probably not necessary following extended lateral approach for ORIF of calcaneal fractures. Level II, comparative study. © The Author(s) 2016.

Stress and ano-colorectal surgery in newborn/infant: role of anesthesia.

PubMed

Bozza, P; Morini, F; Conforti, A; Sgrò, S; Laviani Mancinelli, R; Ottino, S; Bagolan, P; Picardo, S

2012-08-01

The best anesthesia for newborns/infants necessitating colorectal surgery remains questionable. Endovenous and locoregional anesthesiological approaches were compared to determine the influence on stress response. Patients with anorectal malformations or Hirschsprung's disease were randomized to inhalatory/epidural anesthesia (IPA) or inhalatory/endovenous anesthesia (IEA). Heart rate, blood pressure, oxygen saturation, serum concentrations of dehydroepiandrosterone, cortisol, and glucose were recorded 24 h before operation (T0), after tracheal intubation (T1), 120 min after skin incision (T2), 60 min (T3) and 24 h after operation (T4). Seventeen patients were enrolled in the study, 8 receiving IPA, and 9 IEA. Heart rate, blood pressure, oxygen saturation remained stable and normal, without statistical differences between the two groups, during the study period. Similar cortisol and glucose levels showed no statistical differences between groups. Dehydroepiandrosterone values were significantly higher in IEA during anesthesia (T1-T3) compared with IPA (T1: 494.0 vs. 266.5, p < 0.05; T2: 444.0 vs. 201.0, p < 0.05; T3: 385.0 vs. 305.0, p < 0.05). This study suggests that epidural and endovenous anesthesia are both effective in intra- and postoperative period. This preliminary report suggests that IPA is more efficient compared to IEA in controlling stress reaction related to surgery. Further larger studies are needed to confirm these findings.

40 CFR 264.301 - Design and operating requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... subsurface soil or ground water or surface water at anytime during the active life (including the closure... waste or leachate to which they are exposed, climatic conditions, the stress of installation, and the stress of daily operation; (ii) Placed upon a foundation or base capable of providing support to the...

76 FR 1644 - Biweekly Notice; Applications and Amendments to Facility Operating Licenses Involving No...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-11

... tubesheet in that region. At normal operating pressures, leakage from primary water stress corrosion... cause failure. The EDG reliability will thereby be potentially increased by reducing the stresses on the..., ``Bases for Plugging Degraded PWR [pressurized-water reactor] Steam Generator Tubes,'' margins against...

40 CFR 265.443 - Design and operating requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... free-drain treated wood drippage, rain and other waters, or solutions of drippage and water or other..., climatic conditions, the stress of installation, and the stress of daily operations, e.g., variable and... or groundwater or surface water at any time during the active life (including the closure period) of...

40 CFR 265.443 - Design and operating requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... free-drain treated wood drippage, rain and other waters, or solutions of drippage and water or other..., climatic conditions, the stress of installation, and the stress of daily operations, e.g., variable and... or groundwater or surface water at any time during the active life (including the closure period) of...

Low lifetime stress exposure is associated with reduced stimulus–response memory

PubMed Central

Goldfarb, Elizabeth V.; Shields, Grant S.; Daw, Nathaniel D.; Slavich, George M.; Phelps, Elizabeth A.

2017-01-01

Exposure to stress throughout life can cumulatively influence later health, even among young adults. The negative effects of high cumulative stress exposure are well-known, and a shift from episodic to stimulus–response memory has been proposed to underlie forms of psychopathology that are related to high lifetime stress. At the other extreme, effects of very low stress exposure are mixed, with some studies reporting that low stress leads to better outcomes, while others demonstrate that low stress is associated with diminished resilience and negative outcomes. However, the influence of very low lifetime stress exposure on episodic and stimulus–response memory is unknown. Here we use a lifetime stress assessment system (STRAIN) to assess cumulative lifetime stress exposure and measure memory performance in young adults reporting very low and moderate levels of lifetime stress exposure. Relative to moderate levels of stress, very low levels of lifetime stress were associated with reduced use and retention (24 h later) of stimulus–response (SR) associations, and a higher likelihood of using context memory. Further, computational modeling revealed that participants with low levels of stress exhibited worse expression of memory for SR associations than those with moderate stress. These results demonstrate that very low levels of stress exposure can have negative effects on cognition. PMID:28298555

Methanogenesis control by employing various environmental stress conditions in two-chambered microbial fuel cells.

PubMed

Chae, Kyu-Jung; Choi, Mi-Jin; Kim, Kyoung-Yeol; Ajayi, F F; Park, Woosin; Kim, Chang-Won; Kim, In S

2010-07-01

This study examines methanogen activity in microbial fuel cells when exposed to various environmental stresses, such as oxygen, low pH, low temperature, inhibitor (2-bromoethanesulfonate (BES)), and variations in external resistance. Controlling methanogenesis resulted in an increase in Coulombic efficiency (CE) because it was a major cause of electron loss. Methane was mainly produced from aceticlastic methanogenesis, rather than by syntrophic acetate oxidation, with Methanosarcinaceae being the primary contributor. Lowering the resistance from 600 to 50 Omega reduced the methanogenic electron loss by 24%; however, changing the temperature or pH level had little effect. A BES injection was the most potent strategy for the selective inhibition of methanogens without damaging exoelectrogens. The addition of 0.1-0.27 mM BES increased the CE from 35% to 70%. Oxygen stress successfully inhibited methanogens, while slightly suppressing the exoelectrogens, and is believed to be a practical option due to its low operating cost. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Guidelines for Perioperative Management of the Diabetic Patient

PubMed Central

Surani, Salim R.

2015-01-01

Management of glycemic levels in the perioperative setting is critical, especially in diabetic patients. The effects of surgical stress and anesthesia have unique effects on blood glucose levels, which should be taken into consideration to maintain optimum glycemic control. Each stage of surgery presents unique challenges in keeping glucose levels within target range. Additionally, there are special operative conditions that require distinctive glucose management protocols. Interestingly, the literature still does not report a consensus perioperative glucose management strategy for diabetic patients. We hope to outline the most important factors required in formulating a perioperative diabetic regimen, while still allowing for specific adjustments using prudent clinical judgment. Overall, through careful glycemic management in perioperative patients, we may reduce morbidity and mortality and improve surgical outcomes. PMID:26078998

Perceived Stress in Family Caregivers of Individuals With Mental Illness.

PubMed

Masa'Deh, Rami

2017-06-01

The current study aimed to measure the stress levels of family caregivers of individuals with mental illness and compare their stress levels according to the diagnosis and other sociodemographic characteristics. The sample comprised 310 family caregivers of individuals with mental illness in Jordan. Family caregivers completed a demographic checklist and the Arabic version of the Perceived Stress Scale 10-Item (PSS-10) questionnaire. A significant difference was found in PSS-10 levels among family caregivers according to gender, diagnosis of their family member, and time since diagnosis. Female caregivers reported significantly higher stress levels than male caregivers. Family members of individuals with schizophrenia reported the highest stress levels (p < 0.001). Results also indicated that there was a significant negative correlation between PSS-10 levels of family caregivers and time since diagnosis. Investigating stress levels in family members of individuals with mental illness may be helpful when designing interventions to reduce such stress. [Journal of Psychosocial Nursing and Mental Health Services, 55(6), 30-35.]. Copyright 2017, SLACK Incorporated.

Job satisfaction, stress and burnout in anaesthesia: relevant topics for anaesthesiologists and healthcare managers?

PubMed

Rama-Maceiras, Pablo; Parente, Suzana; Kranke, Peter

2012-07-01

Job satisfaction is defined as an employee's positive reaction towards his/her work. Changes in health policies, which are seen as a threat to the autonomy of health workers, are associated with a decrease in satisfaction levels, increase burnout among physicians, and may impair the quality and safety of care. The work environment of anaesthesiologists include stressful areas such as the operating theatre, the ICU, and the emergency setting, and this has been linked to higher levels of stress and lower satisfaction. We frequently lack feedback from patients and even our colleagues despite usually working within a team. Nevertheless, job satisfaction and burnout rates in anaesthesia are similar to other specialties. The most relevant factors in job satisfaction are worker autonomy, control of the working environment, recognition of our value, professional relationships, leadership and organisational justice. Although these can be manipulated for good or otherwise, there are additional, less malleable factors such as personality, expectations and motivation of the employee, that play a part. Within organisations there needs to be the will to evaluate employees' satisfaction, to improve their work environment and to develop strategies and coping mechanisms for professional stress. Personal wellness should also be nurtured, as a satisfactory work-life balance and an adequate social support network might act as a buffer for dissatisfaction and burnout. Improvement in satisfaction might create a positive work climate that would benefit both the safety of our patients and our profession.

Feasibility of water injection into the turbine coolant to permit gas turbine contingency power for helicopter application

NASA Technical Reports Server (NTRS)

Vanfossen, G. J.

1983-01-01

A system which would allow a substantially increased output from a turboshaft engine for brief periods in emergency situations with little or no loss of turbine stress rupture life is proposed and studied analytically. The increased engine output is obtained by overtemperaturing the turbine; however, the temperature of the compressor bleed air used for hot section cooling is lowered by injecting and evaporating water. This decrease in cooling air temperature can offset the effect of increased gas temperature and increased shaft speed and thus keep turbine blade stress rupture life constant. The analysis utilized the NASA-Navy-Engine-Program or NNEP computer code to model the turboshaft engine in both design and off-design modes. This report is concerned with the effect of the proposed method of power augmentation on the engine cycle and turbine components. A simple cycle turboshaft engine with a 16:1 pressure ratio and a 1533 K (2760 R) turbine inlet temperature operating at sea level static conditions was studied to determine the possible power increase and the effect on turbine stress rupture life that could be expected using the proposed emergency cooling scheme. The analysis showed a 54 percent increse in output power can be achieved with no loss in gas generator turbine stress rupture life. A 231 K (415 F) rise in turbine inlet temperature is required for this level of augmentation. The required water flow rate was found to be .0109 kg water per kg of engine air flow.

Study of Serum Malondialdehyde Level in Opioid and Methamphetamine Dependent Patients.

PubMed

Najafi, Khadije; Ahmadi, Sajad; Rahpeyma, Mahdi; Khazaie, Habibolah; Vaisi-Raygani, Asad; Moini, Ali; Kiani, Amir

2017-10-01

Opioid compound and methamphetamine are commonly used in drug abuse; these can disrupt the normal function of cellular and molecular systems, leading to several events such as oxidative stress, aging, apoptosis, and necrosis. Malondialdehyde (MDA) is the most important biomarker for evaluation of oxidative stress and determination of lipid peroxidation. In this study, 42 drug abusers and 22 healthy persons participated as case and control groups, respectively. MDA in volunteer sera was determined by high-performance liquid chromatography (HPLC) with fluorescence detection after pre-column derivatization using thiobarbituric acid. The analysis was performed on a ODS column by spectrofluorometer detection, operated at excitation of 515 nm and emission of 535 nm. A mixture of phosphate buffer (0.05 M, pH 6.8), containing potassium monobasic phosphate and methanol (60:40, v/v) at a flow rate of 1 ml/min, was used as the mobile phase. The retention time of MDA-TBA was 3.2 min. Our findings showed that the MDA level increased in the opioid and methamphetamine abusers when compared to the control group (P<0.05); however, no significant difference was observed between the opioid and methamphetamine groups. A state of oxidative stress during biological processes leads to lipid peroxidation, DNA damage, biomolecule dysfunctions, and many other diseases. Since it is impossible to eradicate the drug addiction, we should reduce the side effects of drug abuse, such as oxidative stress, by intake of proper nutrition and antioxidants.

Safety culture in the gynecology robotics operating room.

PubMed

Zullo, Melissa D; McCarroll, Michele L; Mendise, Thomas M; Ferris, Edward F; Roulette, G D; Zolton, Jessica; Andrews, Stephen J; von Gruenigen, Vivian E

2014-01-01

To measure the safety culture in the robotics surgery operating room before and after implementation of the Robotic Operating Room Computerized Checklist (RORCC). Prospective study. Gynecology surgical staff (n = 32). An urban community hospital. The Safety Attitudes Questionnaire domains examined were teamwork, safety, job satisfaction, stress recognition, perceptions of management, and working conditions. Questions and domains were described using percent agreement and the Cronbach alpha. Paired t-tests were used to describe differences before and after implementation of the checklist. Mean (SD) staff age was 46.7 (9.5) years, and most were women (78%) and worked full-time (97%). Twenty respondents (83% of nurses, 80% of surgeons, 66% of surgical technicians, and 33% of certified registered nurse anesthetists) completed the Safety Attitudes Questionnaire; 6 were excluded because of non-matching identifiers. Before RORCC implementation, the highest quality of communication and collaboration was reported by surgeons and surgical technicians (100%). Certified registered nurse anesthetists reported only adequate levels of communication and collaboration with other positions. Most staff reported positive responses for teamwork (48%; α = 0.81), safety (47%; α = 0.75), working conditions (37%; α = 0.55), stress recognition (26%; α = 0.71), and perceptions of management (32%; α = 0.52). No differences were observed after RORCC implementation. Quality of communication and collaboration in the gynecology robotics operating room is high between most positions; however, safety attitude responses are low overall. No differences after RORCC implementation and low response rates may highlight lack of staff support. Copyright © 2014. Published by Elsevier Inc.

Constitutive expression of a salinity-induced wheat WRKY transcription factor enhances salinity and ionic stress tolerance in transgenic Arabidopsis thaliana.

PubMed

Qin, Yuxiang; Tian, Yanchen; Han, Lu; Yang, Xinchao

2013-10-25

The isolation and characterization of TaWRKY79, a wheat class II WRKY transcription factor, is described. Its 1297 bp coding region includes a 987 bp long open reading frame. TaWRKY79 was induced by stressing seedlings with either NaCl or abscisic acid (ABA). When a fusion between an 843 bp segment upstream of the TaWRKY79 coding sequence and GUS was introduced into Arabidopsis thaliana, GUS staining indicated that this upstream segment captured the sequence(s) required to respond to ABA or NaCl treatment. When TaWRKY79 was constitutively expressed as a transgene in A. thaliana, the transgenic plants showed an improved capacity to extend their primary root in the presence of either 100 mM NaCl, 10 mM LiCl or 2 μM ABA. The inference was that TaWRKY79 enhanced the level of tolerance to both salinity and ionic stress, while reducing the level of sensitivity to ABA. The ABA-related genes ABA1, ABA2 ABI1 and ABI5 were all up-regulated in the TaWRKY79 transgenic plants, suggesting that the transcription factor operates in an ABA-dependent pathway. Copyright © 2013. Published by Elsevier Inc.

Impact of wastewater treatment configuration and seasonal conditions on thyroid hormone disruption and stress effects in Rana catesbeiana tailfin.

PubMed

Wojnarowicz, Pola; Ogunlaja, Olumuyiwa O; Xia, Chen; Parker, Wayne J; Helbing, Caren C

2013-12-03

Improved endocrine disrupting compound (EDC) removal is desirable in municipal wastewater treatment plants (MWWTPs) although increased removal does not always translate into reduced biological activity. Suitable methods for determining reduction in biological activity of effluents are needed. In order to determine which MWWTPs are the most effective at removing EDC activities, we operated three configurations of pilot sized biological reactors (conventional activated sludge, CAS; nitrifying activated sludge, NAS; and biological nutrient removal, BNR) receiving the same influent under simulated winter and summer conditions. As frogs are model organisms for the study of thyroid hormone (TH) action, we used the North American species Rana catesbeiana in a cultured tadpole tailfin (C-fin) assay to compare the effluents. TH-responsive (thyroid hormone receptors alpha (thra) and beta (thrb)) and stress-responsive (superoxide dismutase, catalase, and heat shock protein 30) mRNA transcript levels were examined. Effluents infrequently perturbed stress-responsive transcript abundance but thra/thrb levels were significantly altered. In winter conditions, CAS caused frequent TH perturbations while BNR caused none. In summer conditions, however, BNR caused substantial TH perturbations while CAS caused few. Our findings contrast other studies of seasonal variations of EDC removal and accentuate the importance of utilizing appropriate biological readouts for assessing EDC activities.

Split-root systems applied to the study of the legume-rhizobial symbiosis: what have we learned?

PubMed

Larrainzar, Estíbaliz; Gil-Quintana, Erena; Arrese-Igor, Cesar; González, Esther M; Marino, Daniel

2014-12-01

Split-root system (SRS) approaches allow the differential treatment of separate and independent root systems, while sharing a common aerial part. As such, SRS is a useful tool for the discrimination of systemic (shoot origin) versus local (root/nodule origin) regulation mechanisms. This type of approach is particularly useful when studying the complex regulatory mechanisms governing the symbiosis established between legumes and Rhizobium bacteria. The current work provides an overview of the main insights gained from the application of SRS approaches to understand how nodule number (nodulation autoregulation) and nitrogen fixation are controlled both under non-stressful conditions and in response to a variety of stresses. Nodule number appears to be mainly controlled at the systemic level through a signal which is produced by nodule/root tissue, translocated to the shoot, and transmitted back to the root system, involving shoot Leu-rich repeat receptor-like kinases. In contrast, both local and systemic mechanisms have been shown to operate for the regulation of nitrogenase activity in nodules. Under drought and heavy metal stress, the regulation is mostly local, whereas the application of exogenous nitrogen seems to exert a regulation of nitrogen fixation both at the local and systemic levels. © 2014 Institute of Botany, Chinese Academy of Sciences.

Facility-level association of preoperative stress testing and postoperative adverse cardiac events.

PubMed

Valle, Javier A; Graham, Laura; Thiruvoipati, Thejasvi; Grunwald, Gary; Armstrong, Ehrin J; Maddox, Thomas M; Hawn, Mary T; Bradley, Steven M

2018-06-22

Despite limited indications, preoperative stress testing is often used prior to non-cardiac surgery. Patient-level analyses of stress testing and outcomes are limited by case mix and selection bias. Therefore, we sought to describe facility-level rates of preoperative stress testing for non-cardiac surgery, and to determine the association between facility-level preoperative stress testing and postoperative major adverse cardiac events (MACE). We identified patients undergoing non-cardiac surgery within 2 years of percutaneous coronary intervention in the Veterans Affairs (VA) Health Care System, from 2004 to 2011, facility-level rates of preoperative stress testing and postoperative MACE (death, myocardial infarction (MI) or revascularisation within 30 days). We determined risk-standardised facility-level rates of stress testing and postoperative MACE, and the relationship between facility-level preoperative stress testing and postoperative MACE. Among 29 937 patients undergoing non-cardiac surgery at 131 VA facilities, the median facility rate of preoperative stress testing was 13.2% (IQR 9.7%-15.9%; range 6.0%-21.5%), and 30-day postoperative MACE was 4.0% (IQR 2.4%-5.4%). After risk standardisation, the median facility-level rate of stress testing was 12.7% (IQR 8.4%-17.4%) and postoperative MACE was 3.8% (IQR 2.3%-5.6%). There was no correlation between risk-standardised stress testing and composite MACE at the facility level (r=0.022, p=0.81), or with individual outcomes of death, MI or revascularisation. In a national cohort of veterans undergoing non-cardiac surgery, we observed substantial variation in facility-level rates of preoperative stress testing. Facilities with higher rates of preoperative stress testing were not associated with better postoperative outcomes. These findings suggest an opportunity to reduce variation in preoperative stress testing without sacrificing patient outcomes. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

BRST Exactness of Stress-Energy Tensors

NASA Astrophysics Data System (ADS)

Miyata, Hideo; Sugimoto, Hiroshi

BRST commutators in the topological conformal field theories obtained by twisting N=2 theories are evaluated explicitly. By our systematic calculations of the multiple integrals which contain screening operators, the BRST exactness of the twisted stress-energy tensors is deduced for classical simple Lie algebras and general level k. We can see that the paths of integrations do not affect the result, and further, the N=2 coset theories are obtained by deleting two simple roots with Kac-label 1 from the extended Dynkin diagram; in other words, by not performing the integrations over the variables corresponding to the two simple roots of Kac-Moody algebras. It is also shown that a series of N=1 theories are generated in the same way by deleting one simple root with Kac-label 2.

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.

Oxidized Low-Density-Lipoprotein Accumulation is Associated with Liver Fibrosis in Experimental Cholestasis

PubMed Central

Karadeniz, Güldeniz; Acikgoz, Serefden; Tekin, Ishak Ozel; Tascýlar, Oge; Gun, Banu Dogan; Cömert, Mustafa

2008-01-01

OBJECTIVE The aim of the present study was to examine the probable relationship between the accumulation of oxLDL and hepatic fibrogenesis in cholestatic rats. INTRODUCTION There is growing evidence to support the current theories on how oxidative stress that results in lipid peroxidation is involved in the pathogenesis of cholestatic liver injury and fibrogenesis. One of the major and early lipid peroxidation products, OxLDL, is thought to play complex roles in various immuno-inflammatory mechanisms. METHODS A prolonged (21-day) experimental bile duct ligation was performed on Wistar-albino rats. Biochemical analysis of blood, histopathologic evaluation of liver, measurement of the concentration of malondialdehyde (MDA) and superoxide-dismutase (SOD) in liver tissue homogenates, and immunofluorescent staining for oxLDL in liver tissue was conducted in bile-duct ligated (n = 8) and sham-operated rats (n = 8). RESULTS Significantly higher levels of MDA and lower concentrations of SOD were detected in jaundiced rats than in the sham-operated rats. Positive oxLDL staining was also observed in liver tissue sections of jaundiced rats. Histopathological examination demonstrated that neither fibrosis nor other indications of hepatocellular injury were found in the sham-operated group, while features of severe hepatocellular injury, particularly fibrosis, were found in jaundiced rats. CONCLUSION Our results support the finding that either oxLDLs are produced as an intermediate agent during exacerbated oxidative stress or they otherwise contribute to the various pathomechanisms underlying the process of liver fibrosis. Whatever the mechanism, it is clear that an association exists between elevated oxLDL levels and hepatocellular injury, particularly with fibrosis. Further studies are needed to evaluate the potential effects of oxLDLs on the progression of secondary biliary cirrhosis. PMID:18719767

Stressed photoconductive detector for far-infrared space applications

NASA Technical Reports Server (NTRS)

Wang, J.-Q.; Richards, P. L.; Beeman, J. W.; Haller, E. E.

1987-01-01

An optimized leaf-spring apparatus for applying uniaxial stress to a Ge:Ga far-IR photoconductor has been designed and tested. This design has significant advantages for space applications which require high quantum efficiency and stable operation over long periods of time. The important features include adequate spring deflection with relatively small overall size, torque-free stress, easy measurement of applied stress, and a detector configuration with high responsivity. One-dimensional arrays of stressed photoconductors can be constructed using this design. A peak responsivity of 38 A/W is achieved in a detector with a cutoff wavelength of 200 microns, which was operated at a temperature of 2.0 K and a bias voltage equal to one-half of the breakdown voltage.

Method of preparing a two-way shape memory alloy

DOEpatents

Johnson, A.D.

1984-03-06

A two-way shape memory alloy, a method of training a shape memory alloy, and a heat engine employing the two-way shape memory alloy to do external work during both heating and cooling phases are disclosed. The alloy is heated under a first training stress to a temperature which is above the upper operating temperature of the alloy, then cooled to a cold temperature below the zero-force transition temperature of the alloy, then deformed while applying a second training stress which is greater in magnitude than the stress at which the alloy is to be operated, then heated back to the hot temperature, changing from the second training stress back to the first training stress. 8 figs.

Changes in the Concentrations of Mediators of Inflammation and Oxidative Stress in Exhaled Breath Condensate During Liver Transplantation and Their Relations With Postoperative ARDS.

PubMed

Liu, Dezhao; Luo, Gangjian; Luo, Chenfang; Wang, Tao; Sun, Guoliang; Hei, Ziqing

2015-05-01

Oxidative stress and inflammatory responses are thought to be involved in the pathogenesis of ARDS, which is one of the most serious complications of orthotopic liver transplantation (OLT). The collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining clinical samples from the lungs. However, the changes of mediators of inflammation and oxidative stress in EBC remain unclear. Therefore, the aim of this study was to investigate the changes of mediators in EBC from OLT subjects and the relations between these mediators and ARDS. The levels of mediators of oxidative stress (superoxide dismutase [SOD], malondialdehyde [MDA], H2O2, NO, and 8-iso-prostaglandin F2α) and of inflammatory factors (tumor necrosis factor-α[TNF-α], interleukin [IL]-8, and IL-10) were measured in EBC and serum samples collected from 28 subjects before OLT surgery and at 2 and 4 h after the anhepatic phase. The diagnostic value for ARDS until the 3 days following transplantation was evaluated. Eighteen subjects developed ARDS after OLT. The concentrations of TNF-α, IL-8, MDA, NO, H2O2, and 8-iso-prostaglandin F2α were much higher in the ARDS group than in the control group, whereas the levels of IL-10 and SOD were lower in the ARDS group than in the control group. The serum levels of mediators of oxidative stress or inflammation were closely related to EBC levels. Receiver operating characteristic analysis showed that areas under the curves for MDA, NO, H2O2, 8-iso-prostaglandin F2α, TNF-α, IL-8, SOD, and IL-10 were 0.88, 0.88, 0.78, 0.84, 0.84, 0.94, 0.81, and 0.84 at 2 h after graft reperfusion and 0.98, 0.88, 0.92, 0.79, 0.95, 0.83, 0.88, and 0.97 at 4 h after graft reperfusion. EBC analysis is a noninvasive method for detecting mediators of inflammation and oxidative stress from the lungs. This method could be used to predict the higher incidence of ARDS induced by OLT. Copyright © 2015 by Daedalus Enterprises.

Interindividual differences in stress sensitivity: basal and stress-induced cortisol levels differentially predict neural vigilance processing under stress.

PubMed

Henckens, Marloes J A G; Klumpers, Floris; Everaerd, Daphne; Kooijman, Sabine C; van Wingen, Guido A; Fernández, Guillén

2016-04-01

Stress exposure is known to precipitate psychological disorders. However, large differences exist in how individuals respond to stressful situations. A major marker for stress sensitivity is hypothalamus-pituitary-adrenal (HPA)-axis function. Here, we studied how interindividual variance in both basal cortisol levels and stress-induced cortisol responses predicts differences in neural vigilance processing during stress exposure. Implementing a randomized, counterbalanced, crossover design, 120 healthy male participants were exposed to a stress-induction and control procedure, followed by an emotional perception task (viewing fearful and happy faces) during fMRI scanning. Stress sensitivity was assessed using physiological (salivary cortisol levels) and psychological measures (trait questionnaires). High stress-induced cortisol responses were associated with increased stress sensitivity as assessed by psychological questionnaires, a stronger stress-induced increase in medial temporal activity and greater differential amygdala responses to fearful as opposed to happy faces under control conditions. In contrast, high basal cortisol levels were related to relative stress resilience as reflected by higher extraversion scores, a lower stress-induced increase in amygdala activity and enhanced differential processing of fearful compared with happy faces under stress. These findings seem to reflect a critical role for HPA-axis signaling in stress coping; higher basal levels indicate stress resilience, whereas higher cortisol responsivity to stress might facilitate recovery in those individuals prone to react sensitively to stress. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Moderating effects of salivary testosterone levels on associations between job demand and psychological stress response in Japanese medical workers

PubMed Central

HIROKAWA, Kumi; MIWA, Machiko; TANIGUCHI, Toshiyo; TSUCHIYA, Masao; KAWAKAMI, Norito

2015-01-01

Levels of job stress have been shown to be inversely associated with testosterone levels, but some inconsistent results have been documented. We investigated the moderating effects of testosterone levels on associations between job stress-factors and psychological stress responses in Japanese medical workers. The participants were 63 medical staff (20 males and 43 women; mean age: 30.6 years; SD=7.3) in Okayama, Japan. Their job-stress levels and psychological stress responses were evaluated using self-administered questionnaires, and their salivary testosterone collected. Multiple regression analyses showed that job demand was positively associated with stress responses in men and women. An interaction between testosterone and support from colleagues had a significant effect on depression and anxiety for women. In women with lower testosterone levels, a reducing effect of support from colleagues on depression and anxiety was intensified. In women with higher testosterone levels, depression and anxiety levels were identical regardless of support from colleagues. Testosterone may function as a moderator between perceived work environment and psychological stress responses for female medical workers. PMID:26632120

Dorsal aorta catheterization in rainbow trout (Salmo gairdneri) I. Its validity in the study of blood gonadotropin patterns.

PubMed

Zohar, Y

1980-01-01

The use of a dorsal aorta catheterization technique to study gonadotropin secretion patterns in the rainbow trout was tested. Heparin used to flush the cannula between repetitive samplings did not have any effect on plasma GTH levels. Catheterization resulted in a slight short-term change in those levels. The gonadotropin levels returned to their initial values as soon as 30 min to 6 hrs after the operation. From then on, the GTH levels remained close to the initial values in fish exhibiting normal feeding behaviour, whereas they tended to decrease in "stressed" females which did not eat normally. The fish which adapted well to dorsal aortic catheterization did not show any changes in the diurnal pattern of GTH levels or in normal gonadal function and GTH profiles during the processes of oocyte maturation and ovulation. It is concluded that individual catheterized trout can be used advantageously for studying gonadotropin secretion patterns after a 3-day recovery period and the elimination of those fish which neither resume normal feeding nor return to initial, pre-operative GTH levels. Using this technique, it was demonstrated that hypophysial GTH release in trout with oocytes undergoing active vitellogenesis is probably effected by short-term bursts (pulses) of secretion.

Wall Shear Stress, Wall Pressure and Near Wall Velocity Field Relationships in a Whirling Annular Seal

NASA Technical Reports Server (NTRS)

Morrison, Gerald L.; Winslow, Robert B.; Thames, H. Davis, III

1996-01-01

The mean and phase averaged pressure and wall shear stress distributions were measured on the stator wall of a 50% eccentric annular seal which was whirling in a circular orbit at the same speed as the shaft rotation. The shear stresses were measured using flush mounted hot-film probes. Four different operating conditions were considered consisting of Reynolds numbers of 12,000 and 24,000 and Taylor numbers of 3,300 and 6,600. At each of the operating conditions the axial distribution (from Z/L = -0.2 to 1.2) of the mean pressure, shear stress magnitude, and shear stress direction on the stator wall were measured. Also measured were the phase averaged pressure and shear stress. These data were combined to calculate the force distributions along the seal length. Integration of the force distributions result in the net forces and moments generated by the pressure and shear stresses. The flow field inside the seal operating at a Reynolds number of 24,000 and a Taylor number of 6,600 has been measured using a 3-D laser Doppler anemometer system. Phase averaged wall pressure and wall shear stress are presented along with phase averaged mean velocity and turbulence kinetic energy distributions located 0.16c from the stator wall where c is the seal clearance. The relationships between the velocity, turbulence, wall pressure and wall shear stress are very complex and do not follow simple bulk flow predictions.

Bias stress instability of double-gate a-IGZO TFTs on polyimide substrate

NASA Astrophysics Data System (ADS)

Cho, Won-Ju; Ahn, Min-Ju

2017-09-01

In this study, flexible double-gate thin-film transistor (TFT)-based amorphous indium-galliumzinc- oxide (a-IGZO) was fabricated on a polyimide substrate. Double-gate operation with connected front and back gates was compared with a single-gate operation. As a result, the double-gate a- IGZO TFT exhibited enhanced electrical characteristics as well as improved long-term reliability. Under positive- and negative-bias temperature stress, the threshold voltage shift of the double-gate operation was much smaller than that of the single-gate operation.

Dose response relationship in anti-stress gene regulatory networks.

PubMed

Zhang, Qiang; Andersen, Melvin E

2007-03-02

To maintain a stable intracellular environment, cells utilize complex and specialized defense systems against a variety of external perturbations, such as electrophilic stress, heat shock, and hypoxia, etc. Irrespective of the type of stress, many adaptive mechanisms contributing to cellular homeostasis appear to operate through gene regulatory networks that are organized into negative feedback loops. In general, the degree of deviation of the controlled variables, such as electrophiles, misfolded proteins, and O2, is first detected by specialized sensor molecules, then the signal is transduced to specific transcription factors. Transcription factors can regulate the expression of a suite of anti-stress genes, many of which encode enzymes functioning to counteract the perturbed variables. The objective of this study was to explore, using control theory and computational approaches, the theoretical basis that underlies the steady-state dose response relationship between cellular stressors and intracellular biochemical species (controlled variables, transcription factors, and gene products) in these gene regulatory networks. Our work indicated that the shape of dose response curves (linear, superlinear, or sublinear) depends on changes in the specific values of local response coefficients (gains) distributed in the feedback loop. Multimerization of anti-stress enzymes and transcription factors into homodimers, homotrimers, or even higher-order multimers, play a significant role in maintaining robust homeostasis. Moreover, our simulation noted that dose response curves for the controlled variables can transition sequentially through four distinct phases as stressor level increases: initial superlinear with lesser control, superlinear more highly controlled, linear uncontrolled, and sublinear catastrophic. Each phase relies on specific gain-changing events that come into play as stressor level increases. The low-dose region is intrinsically nonlinear, and depending on the level of local gains, presence of gain-changing events, and degree of feedforward gene activation, this region can appear as superlinear, sublinear, or even J-shaped. The general dose response transition proposed here was further examined in a complex anti-electrophilic stress pathway, which involves multiple genes, enzymes, and metabolic reactions. This work would help biologists and especially toxicologists to better assess and predict the cellular impact brought about by biological stressors.

Kinetics of plasma heat shock protein HSP-70 release in coronary artery surgery: on-pump versus off-pump.

PubMed

Pizon, M T; Gburek, T; Pizon, M; Sztefko, K

2006-12-01

Heat shock protein HSP-70 is known as protective chaperone molecule synthetized in response following ischemia and stress agents. It is detected in the myocardium and endothelium as well as in the circulation. Damaged as well as viable but exposed to stress cells contribute to the release of HSP-70 into the circulation. The aim of the study was to investigate if cardiopulmonary bypss (CPB) leads to more circulating HSP-70, on the basis of comparison dynamics of plasma concentration HSP-70 in 8 men undergoing procedures with the use of CPB (coronary artery bypass grafting, CABG group) and 8 men undergoing off-pump surgery (OPCAB group). Blood samples were taken preoperatively, twice intraoperatively, immediately after surgical procedure (1 h) and 24-hours thereafter. The concentration of plasma HSP-70 was measured by means of immunoassay. The derived results were compared statistically with the frequency of incidence postoperative atrial fibrillation (AF). In CABG group was observed continuous gradual increase of plasma HSP-70 concentration during the operation with the peak 1 h after surgery (P<0.01), in striking contrast to OPCAB group, in which was detected small, but non statistically significant increase of HSP-70 1 h after operation. Significantly more of circulating HSP-70 it was detected in CABG group during the operation and 1 h after surgery (CABG vs OPCAB, respectively P<0.015 and P<0.028). In both groups among patients witch AF it was found higher postoperative values of circulating HSP-70 compared with the non-AF group (P=0.0415). The use of CPB leads to significant more release of HSP-70 into the circulation. According to our findings high plasma concentration of HSP-70 may be the measure of operative cellular stress, ischemia or injury and may be related with greater onset of postoperative AF. High circulating HSP-70 levels is connected with higher incidence of postoperative AF after open heart surgery.

Occupational stressors, burnout and coping strategies between hospital and community psychiatric nurses in a Dublin region.

PubMed

McTiernan, K; McDonald, N

2015-04-01

Burnout negatively impacts the delivery of mental health services. Psychiatric nurses face stressors that are distinct from other nursing specialities. The research was conducted in Ireland and captured a relatively large sample of respondents. The results compared the stressors, coping strategies and burnout levels between hospital and community-based psychiatric nurses. Occupational stress can negatively impact on the well-being of psychiatric nurses, which in turn can lead to poor client care. There is a dearth of published research conducted in Ireland that examines stress within the discipline. A between-groups study, undertaken in February 2011, investigated stressors, burnout and coping strategies between hospital and community-based psychiatric nurses in a Dublin region. Sixty-nine participants (8 males and 61 females), aged between 18 to 60 years voluntarily completed the Mental Health Professional Stress Scale, the Maslach Burnout Inventory and the PsychNurse Methods of Coping Scale. The findings revealed that nurses were operating in a moderately stressful environment. Stressors focused on organizational issues as opposed to client issues. The main stressors identified were lack of resources, workload and organizational structures/processes. Both groups reported average levels of emotional exhaustion, low levels of depersonalization and average levels of personal accomplishment. A Mann-Whitney U-test and Independent Samples t-test found significant differences between hospital and community-based nurses regarding depersonalization and personal accomplishment, respectively. Hospital nurses reported higher depersonalization scores, and community nurses had a greater sense of personal accomplishment. The personal accomplishment scores of hospital nurses were below mental health professional norms. No significant differences emerged regarding coping strategies. Avoidant coping strategies were favoured by both groups. It is recommended that interventions aimed at increasing personal accomplishment be implemented for both groups of nurses. An investigation of perceived job control and the use of social support would also be insightful. © 2014 John Wiley & Sons Ltd.

Blueberry supplementation attenuates oxidative stress within monocytes and modulates immune cell levels in adults with metabolic syndrome: a randomized, double-blind, placebo-controlled trial.

PubMed

Nair, Anand R; Mariappan, Nithya; Stull, April J; Francis, Joseph

2017-11-15

Blueberries (BB) have been shown to improve insulin sensitivity and endothelial function in obese and pre-diabetic humans, and decrease oxidative stress and inflammation, and ameliorate cardio-renal damage in rodents. This indicates that blueberries have a systemic effect and are not limited to a particular organ system. In order for blueberries to exert beneficial effects on the whole body, the mechanism would logically have to operate through modulation of cellular humoral factors. This study investigated the role of blueberries in modulating immune cell levels and attenuating circulatory and monocyte inflammation and oxidative stress in metabolic syndrome (MetS) subjects. A double-blind, randomized and placebo-controlled study was conducted in adults with MetS, in which they received a blueberry (22.5 g freeze-dried) or placebo smoothie twice daily for six weeks. Free radical production in the whole blood and monocytes, dendritic cell (DC) levels, expression of cytokines in monocytes and serum inflammatory markers were assessed pre- and post-intervention. Baseline free radical levels in MetS subjects' samples were not different between groups. Treatment with blueberries markedly decreased superoxide and total reactive oxygen species (ROS) in whole blood and monocytes compared to the placebo (p ≤ 0.05). The baseline DC numbers in MetS subjects' samples in both groups were not different, however treatment with blueberries significantly increased myeloid DC (p ≤ 0.05) and had no effect on plasmacytoid cells. Blueberry treatment decreased monocyte gene expression of TNFα, IL-6, TLR4 and reduced serum GMCSF in MetS subjects when compared to the placebo treatment (p ≤ 0.05). The findings of the current study demonstrate that blueberries exert immunomodulatory effects and attenuate oxidative stress and inflammation in adults with MetS.

Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic Ball Bearings

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

2016-01-01

Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic NiTi Ball Bearings

NASA Technical Reports Server (NTRS)

Dellacorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

2017-01-01

Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

Use of chaos theory and complex systems modeling to study alcohol effects on fetal condition.

PubMed

Mehl, L E; Manchanda, S

1993-10-01

A systems dynamics computer model to predict birth complications for individual pregnant woman was developed from prospectively conducted data on a database of 125 pregnant women. The model is based upon nonlinear mathematics derived from the study of chaos and complex systems. The model was then tested prospectively on 27 additional pregnant women, making predictions on their level of obstetrical risk. The model was refined until it correctly predicted the outcomes of all 125 cases in the development database. Prediction was made with an accuracy of 25/27 cases for the prospective test cases. Predictions were made for fetal condition at birth, presence or absence of operative delivery, and presence or absence of uterine dysfunction. Then the model was used to explore alcohol use during pregnancy. A reasonable spread of alcohol use existed among subjects, allowing consideration of alcohol effects. Alcohol was found to have differential effects on fetal condition at birth depending upon the presence or absence of high levels of psychosocial stress and the use of other substances. In all cases, the effect of alcohol was only evident after the 10 drinks per week level was reached. For the high-stress/one other substance group, there could be an 18-fold effect on fetal condition at birth. For the low-stress/one other substance group, the effect was only 3-fold, and for the alcohol alone group, the effect was negligible.

Factors associated with high stress levels in adults with diabetes mellitus attending a tertiary diabetes care center, Chennai, Tamil Nadu, India

PubMed Central

Sendhilkumar, Muthappan; Tripathy, Jaya Prasad; Harries, Anthony D.; Dongre, Amol R.; Deepa, Mohan; Vidyulatha, Ashok; Poongothai, Subramanian; Venkatesan, Ulaganathan; Anjana, Ranjit Mohan; Mohan, Viswanathan

2017-01-01

Objective: We aimed to determine perceived stress levels among adults aged >20 years with type 2 diabetes mellitus (DM) in a tertiary care diabetes center, Chennai, Tamil Nadu, India, assess their association with sociodemographic and clinical characteristics and assess the possible risk factors for stress and coping strategies. Methods: A mixed-methods (triangulation design) study with quantitative methodology (survey) and qualitative methodology (interviews) was carried out. Stress levels were assessed among type 2 DM patients attending a diabetes clinic using a 5-point perceived stress scale-10. One-on-one interviews were carried out with 376 participants with DM having high/very high stress levels to understand the reasons for perceived stress and explore their coping mechanisms. Results: The prevalence of high/very high stress was 35% among DM patients. Age 30–40 years, working in professional jobs, and lack of physical activity were factors significantly associated with stress. The perceived major stress inducers were related to family, work, financial issues, and the disease itself. Conclusions: This study showed high levels of stress in more than one-third of DM patients. Potential solutions include regular, formal assessment of stress levels in the clinic, providing integrated counseling and psychological care for DM patients, and promoting physical activity. PMID:28217499

Factors associated with high stress levels in adults with diabetes mellitus attending a tertiary diabetes care center, Chennai, Tamil Nadu, India.

PubMed

Sendhilkumar, Muthappan; Tripathy, Jaya Prasad; Harries, Anthony D; Dongre, Amol R; Deepa, Mohan; Vidyulatha, Ashok; Poongothai, Subramanian; Venkatesan, Ulaganathan; Anjana, Ranjit Mohan; Mohan, Viswanathan

2017-01-01

We aimed to determine perceived stress levels among adults aged >20 years with type 2 diabetes mellitus (DM) in a tertiary care diabetes center, Chennai, Tamil Nadu, India, assess their association with sociodemographic and clinical characteristics and assess the possible risk factors for stress and coping strategies. A mixed-methods (triangulation design) study with quantitative methodology (survey) and qualitative methodology (interviews) was carried out. Stress levels were assessed among type 2 DM patients attending a diabetes clinic using a 5-point perceived stress scale-10. One-on-one interviews were carried out with 376 participants with DM having high/very high stress levels to understand the reasons for perceived stress and explore their coping mechanisms. The prevalence of high/very high stress was 35% among DM patients. Age 30-40 years, working in professional jobs, and lack of physical activity were factors significantly associated with stress. The perceived major stress inducers were related to family, work, financial issues, and the disease itself. This study showed high levels of stress in more than one-third of DM patients. Potential solutions include regular, formal assessment of stress levels in the clinic, providing integrated counseling and psychological care for DM patients, and promoting physical activity.

Radiation response and electrical properties of polymer energy storage capacitors: PVF2, Polysulfone, and Mylar

NASA Technical Reports Server (NTRS)

Edwards, L. R.

1981-01-01

Efforts were made to develop a polymer film capacitor that is tolerant to radiation. The capacitors are to be utilized in a high voltage pulse discharge application. Radiation response data at high dose/dose rate levels are presented for polyvinylidene fluoride (PVF2), polysulfone, and Mylar. The results show that PVF2 is the most radiation tolerant while Mylar is the least tolerant. The data also show that the radiation response is quite dependent on operating electric stress.

The energy cane alternative

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

Alexander, A.G.

This book reviews the conceptual and theoretical background of Saccharum botany, which underlies the growing of cane as a total growth commodity. Management details are provided for energy cane planting, cultivation, harvest, and postharvest operations. Chapters on energy cane utilization stress new developments in lignocellulose conversion plus alternative options for fermentable solids usage. Chapters are also included for the management of alternative grasses to supplement energy cane, and the breeding of new hybrid canes with high biomass attributes at the intergeneric and interspecific levels.

The Influence of Time Management Practices on Job Stress Level among Beginning Secondary Agriculture Teachers

ERIC Educational Resources Information Center

Lambert, Misty D.; Torres, Robert M.; Tummons, John D.

2012-01-01

Monitoring the stress of teachers continues to be important--particularly stress levels of beginning agriculture teachers. The study sought to describe the relationship between beginning teachers' perceived ability to manage their time and their level of stress. The Time Management Practices Inventory and the Job Stress Survey were used to measure…

Finite Element Analysis of Influence of Axial Position of Center of Rotation of a Cervical Total Disc Replacement on Biomechanical Parameters: Simulated 2-Level Replacement Based on a Validated Model.

PubMed

Li, Yang; Zhang, Zhenjun; Liao, Zhenhua; Mo, Zhongjun; Liu, Weiqiang

2017-10-01

Finite element models have been widely used to predict biomechanical parameters of the cervical spine. Previous studies investigated the influence of position of rotational centers of prostheses on cervical biomechanical parameters after 1-level total disc replacement. The purpose of this study was to explore the effects of axial position of rotational centers of prostheses on cervical biomechanics after 2-level total disc replacement. A validated finite element model of C3-C7 segments and 2 prostheses, including the rotational center located at the superior endplate (SE) and inferior endplate (IE), was developed. Four total disc replacement models were used: 1) IE inserted at C4-C5 disc space and IE inserted at C5-C6 disc space (IE-IE), 2) IE-SE, 3) SE-IE, and 4) SE-SE. All models were subjected to displacement control combined with a 50 N follower load to simulate flexion and extension motions in the sagittal plane. For each case, biomechanical parameters, including predicted moments, range of rotation at each level, facet joint stress, and von Mises stress on the ultra-high-molecular-weight polyethylene core of the prostheses, were calculated. The SE-IE model resulted in significantly lower stress at the cartilage level during extension and at the ultra-high-molecular-weight polyethylene cores when compared with the SE-SE construct and did not generate hypermotion at the C4-C5 level compared with the IE-SE and IE-IE constructs. Based on the present analysis, the SE-IE construct is recommended for treating cervical disease at the C4-C6 level. This study may provide a useful model to inform clinical operations. Copyright © 2017 Elsevier Inc. All rights reserved.

40 CFR 264.221 - Design and operating requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... subsurface soil or ground water or surface water at any time during the active life (including the closure... into the liner (but not into the adjacent subsurface soil or ground water or surface water) during the..., climatic conditions, the stress of installation, and the stress of daily operation; (2) Placed upon a...

Computer Pure-Tone and Operator Stress: Report III.

ERIC Educational Resources Information Center

Dow, Caroline; Covert, Douglas C.

Pure-tone sound at 15,750 Herz generated by flyback transformers in many computer and video display terminal (VDT) monitors has stress-related productivity effects in some operators, especially women. College-age women in a controlled experiment simulating half a normal work day showed responses within the first half hour of exposure to a tone…

49 CFR 192.229 - Limitations on welders.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY....227(a)— (1) May not weld on pipe to be operated at a pressure that produces a hoop stress of 20... pipe to be operated at a pressure that produces a hoop stress of less than 20 percent of SMYS unless...

49 CFR 192.229 - Limitations on welders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY....227(a)— (1) May not weld on pipe to be operated at a pressure that produces a hoop stress of 20... pipe to be operated at a pressure that produces a hoop stress of less than 20 percent of SMYS unless...

49 CFR 192.229 - Limitations on welders.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY....227(a)— (1) May not weld on pipe to be operated at a pressure that produces a hoop stress of 20... pipe to be operated at a pressure that produces a hoop stress of less than 20 percent of SMYS unless...

49 CFR 192.229 - Limitations on welders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY....227(a)— (1) May not weld on pipe to be operated at a pressure that produces a hoop stress of 20... pipe to be operated at a pressure that produces a hoop stress of less than 20 percent of SMYS unless...

49 CFR 192.229 - Limitations on welders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY....227(a)— (1) May not weld on pipe to be operated at a pressure that produces a hoop stress of 20... pipe to be operated at a pressure that produces a hoop stress of less than 20 percent of SMYS unless...

Soldiers Working Internationally: Impacts of Masculinity, Military Culture, and Operational Stress on Cross-Cultural Adaptation

ERIC Educational Resources Information Center

Keats, Patrice A.

2010-01-01

This paper explores the ramifications of masculinized military culture and operational stress on cross-cultural adaptation. The author examines how characteristics of military culture may obstruct effective cross-cultural adaptation by promoting a hypermasculinity that tends to oppose effective management of trauma, and thereby suppresses skills…

Effectiveness of the Combat Operational Stress Control Training Program: Expectations of the U.S. Marine Corps

ERIC Educational Resources Information Center

Sipko, Marek M.

2010-01-01

This study evaluated the effectiveness of the U.S. Marine Corps combat operational stress preventive training program to determine whether the program meets the training effectiveness criteria of the Marine Corps. This evaluation entailed both qualitative and quantitative inquiries to answer the subject matter research questions. The…

Trans-Obturator-Tape (T.O.T.) "outside-in" approach in surgical treatment of female stress urinary incontinence.

PubMed

Jovanović, M; Džamić, Z; Aćimović, M; Kajmaković, B; Pejčić, T

2014-01-01

The aim of the study was to analyzed the efficacy and safety of a minimally invasive surgical procedure using the Trans- Obturator-Tape with "outside-in" approach for treatment female stress urinary incontinence. 171 women with stress urinary incontinence (SUI) associated with urethral hypermobility, underwent the T.O.T. procedure (March 2010 to January 2014). 27 patients were previously operated for incontinence. Mean age was 59 years (37-80). 6 patients were having mixed incontinence, and 51 had SUI with urgencies. A non-elastic, polypropylene tape was placed under the mid-urethra. The surgical placement technique utilises a trans-obturator percutaneous approach. All patients underwent post-operative clinical examination, cough-stress test (full bladder), uroflowmetry, and post-voiding residual assessment. Mean follow-up was 22 months (4-45). At 12 months follow-up 91,2% of the patients were completely cured. The overall peri-operative complication rate was 6.4% with no vascular, nerve or bowel injury. 5 patients (2.9%) had post-operative urinary retention. The present study confirms the results obtained by the instigator of the technique, E. Delorme, and allows us to consider T.O.T. as an effective and safe technique for the treatment of female stress urinary incontinence.

Usage of a Trans-Obturator-Tape (T.O.T.) "outside-in" approach in surgical treatment of female stress urinary incontinence.

PubMed

Jovanovic, Mirko; Vuksanović, Aleksandar; Dzamić', Zoran; Aćimović, Miodrag; Radovanović, Milan; Djurasić, Ljubomir

2011-01-01

The aim of the study was to analyzed the efficacy and safety of a new minimally invasive surgical procedure using the Trans-Obturator-Tape with"outside-in" approach for treatment female stress urinary incontinence. 31 women with stress urinary incontinence (SUI) associated with urethral hypermobility, underwent the T.O.T. procedure (March 2010 to January 2011). 5 patients were previously operated for incontinence. Mean age was 59 years (37-80). 10 patients were having mixed incontinence. A non-elastic, polypropylene tape was placed under the mid-urethra. The surgical placement technique utilises a trans-obturator percutaneous approach. All patients underwent post-operative clinical examination, cough-stress test (full bladder), uroflowmetry, and post-voiding residual assessment. Mean follow-up was 5 months (1-9). At 6 months follow-up 96.7% of the patients were completely cured. The overall peri-operative complication rate was 6.4% with no vascular, nerve or bowel injury. One patients (3.4%) had post-operative urinary retention. The present study confirms the results obtained by the instigator of the technique, E. Delorme, and allows us to consider T.O.T. as an effective and safe technique for the treatment of female stress urinary incontinence.

Family support, family stress, and suicidal ideation in a combat-exposed sample of Operation Enduring Freedom/Operation Iraqi Freedom veterans.

PubMed

Gradus, Jaimie L; Smith, Brian N; Vogt, Dawne

2015-01-01

Deployment-related risk factors for suicidal ideation among Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) veterans have received a great deal of attention. Studies show that mental health symptoms mediate the association between most deployment stressors and suicidal ideation; however, family-related factors during deployment are largely unexplored. We examined posttraumatic stress disorder (PTSD) and depression symptoms as mediators of the associations between deployment family support and stress and post-deployment suicidal ideation in combat-exposed OEF/OIF veterans. National cross-sectional mail survey. 1046 veterans responded to the survey. The sample for this study was 978 veterans who experienced combat. Regression-based path analyses were conducted. Family support and stress had direct associations with suicidal ideation. When PTSD and depression symptoms were examined as mediators of these associations, results revealed significant indirect paths through these symptoms. This study contributes to the literature on suicidal ideation risk factors among OEF/OIF veterans. Deployment family support and family stress are associated with suicidal ideation; however these associations occur primarily through mental health symptomatology, consistent with findings observed for other deployment factors. This research supports ongoing efforts to treat mental health symptomatology as a means of suicide prevention.

Climate and Water Vulnerability of the US Electricity Grid Under High Penetrations of Renewable Energy

NASA Astrophysics Data System (ADS)

Macknick, J.; Miara, A.; O'Connell, M.; Vorosmarty, C. J.; Newmark, R. L.

2017-12-01

The US power sector is highly dependent upon water resources for reliable operations, primarily for thermoelectric cooling and hydropower technologies. Changes in the availability and temperature of water resources can limit electricity generation and cause outages at power plants, which substantially affect grid-level operational decisions. While the effects of water variability and climate changes on individual power plants are well documented, prior studies have not identified the significance of these impacts at the regional systems-level at which the grid operates, including whether there are risks for large-scale blackouts, brownouts, or increases in production costs. Adequately assessing electric grid system-level impacts requires detailed power sector modeling tools that can incorporate electric transmission infrastructure, capacity reserves, and other grid characteristics. Here, we present for the first time, a study of how climate and water variability affect operations of the power sector, considering different electricity sector configurations (low vs. high renewable) and environmental regulations. We use a case study of the US Eastern Interconnection, building off the Eastern Renewable Generation Integration Study (ERGIS) that explored operational challenges of high penetrations of renewable energy on the grid. We evaluate climate-water constraints on individual power plants, using the Thermoelectric Power and Thermal Pollution (TP2M) model coupled with the PLEXOS electricity production cost model, in the context of broader electricity grid operations. Using a five minute time step for future years, we analyze scenarios of 10% to 30% renewable energy penetration along with considerations of river temperature regulations to compare the cost, performance, and reliability tradeoffs of water-dependent thermoelectric generation and variable renewable energy technologies under climate stresses. This work provides novel insights into the resilience and reliability of different configurations of the US electric grid subject to changing climate conditions.

Exploring Temporal Patterns of Stress in Adolescent Girls with Headache.

PubMed

Björling, Elin A; Singh, Narayan

2017-02-01

As part of a larger study on perceived stress and headaches in 2009, momentary perceived stress, head pain levels and stress-related symptom data were collected. This paper explores a temporal analysis of the patterns of stress, as well as an analysis of momentary and retrospective stress-related symptoms compared by level of headache activity. Adolescent girls (N = 31) ages 14-18 were randomly cued by electronic diaries 7 times per day over a 21-day period responding to momentary questions about level of head pain, perceived stress and stress-related symptoms. Multivariate general linear modelling was used to determine significant differences among headache groups in relation to temporal patterns of stress. Significant headache group differences were found on retrospective and momentary stress-related symptom measures. A total of 2841 diary responses captured stress levels, head pain and related symptoms. The chronic headache (CH) group reported the highest levels of hourly and daily stress, followed by the moderate headache (MH) and low headache (LH) groups. Patterns of stress for the three headache groups were statistically distinct, illustrating increased stress in girls with more frequent head pain. This evidence suggests that because of increased stress, girls with recurrent head pain are likely a vulnerable population who may benefit from stress-reducing interventions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

[Occupational stress among female police officers].

PubMed

Bezerra, Claudia de Magalhães; Minayo, Maria Cecília de Souza; Constantino, Patrícia

2013-03-01

The scope of this study is occupational stress among female police officers in Rio de Janeiro. A qualitative approach was initially used (interviews, focal groups and observations) to establish their perceptions regarding gender differences in the performance of police work, the relationship between occupational stress and health issues and the strategies used to mitigate this type of stress. A total of 42 participants including female officers and staff and operational and health professionals were involved. The participants link stress to their daily work, cite a number of symptoms and show how family relationships are affected. Stress originates primarily from work management and organizational issues. Gender discrimination and harassment are also perceived as stressors. Psychic suffering is greater among officers in commanding roles, and operational activities are perceived as more stressful due to the risks involved. Physical exercise is seen as the most effective strategy to mitigate the consequences of stress. The conclusions drawn are that, there is a need for organizational and managerial change from the perspective of gender and investment in preventive measures that can reduce the consequences of stress within the Rio de Janeiro police force.

Effects of Music Listening on Cortisol Levels and Propofol Consumption during Spinal Anesthesia

PubMed Central

Koelsch, Stefan; Fuermetz, Julian; Sack, Ulrich; Bauer, Katrin; Hohenadel, Maximilian; Wiegel, Martin; Kaisers, Udo X.; Heinke, Wolfgang

2011-01-01

Background: This study explores effects of instrumental music on the hormonal system (as indicated by serum cortisol and adrenocorticotropic hormone), the immune system (as indicated by immunoglobulin A) and sedative drug requirements during surgery (elective total hip joint replacement under spinal anesthesia with light sedation). This is the first study investigating this issue with a double-blind design using instrumental music. Methodology/Principal Findings: Patients (n = 40) were randomly assigned either to a music group (listening to instrumental music), or to a control group (listening to a non-musical placebo stimulus). Both groups listened to the auditory stimulus about 2 h before, and during the entire intra-operative period (during the intra-operative light sedation, subjects were able to respond lethargically to verbal commands). Results indicate that, during surgery, patients of the music group had a lower propofol consumption, and lower cortisol levels, compared to the control group. Conclusion/Significance: Our data show that listening to music during surgery under regional anesthesia has effects on cortisol levels (reflecting stress-reducing effects) and reduces sedative requirements to reach light sedation. PMID:21716581

Effects of stress on serum triglycerides, nonsterified fatty acids, and total cholesterol levels in male rats after ethanol administration

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

Hershock, D.; Vogel, W.H.

1989-02-09

Serum triglycerides, nonesterified fatty acids (NEFA), and total cholesterol were determined during one hour immobilization stress in adult male Sprague-Dawley rats after ethanol administration (2g/kg, i.p.). Stress and ethanol effects were evaluated in two experiments: (1) rats maintained on Purina Rodent Chow for six weeks and fasted for 24 hours; and (2) rats maintained on the same diet supplemented with 1% cholesterol and 10% peanut oil for six weeks and nonfasted prior to experimentation. Blood was obtained from indwelling jugular catheters. In each experiment, differences were seen in triglyceride and NEFA levels but not in total cholesterol. In the regularmore » diet-fed rats (1), serum triglyceride levels were not affected by either stress or ethanol. However, NEFA levels did show differences in the response to ethanol and stress. A 63% decrease from baseline after 5{prime} of stress was partially abolished by ethanol; instead, a 24% increase was observed. Also, a stress-induced increase in NEFA which occurred after 15{prime} was not observed in the ethanol treated rats; rather, a decrease in NEFA was noted. Total cholesterol did not change in response to stress or ethanol. In the high cholesterol diet-fed rats (2), ethanol did not suppress a stress-induced increase in triglyceride levels. NEFA levels in ethanol-treated rats were higher during the first 15{prime} of stress as compared to stress alone. A decrease in NEFA was however seen in the ethanol-treated rats after 30{prime} of stress and these levels remained lower than the stress alone group. A diet-induced increase in total cholesterol levels was observed; however, no changes were seen due to either or ethanol. Thus, ethanol administration prior to acute immobilization stress did affect serum triglyceride and NEFA levels but did not change total cholesterol.« less

Towards multilevel mental stress assessment using SVM with ECOC: an EEG approach.

PubMed

Al-Shargie, Fares; Tang, Tong Boon; Badruddin, Nasreen; Kiguchi, Masashi

2018-01-01

Mental stress has been identified as one of the major contributing factors that leads to various diseases such as heart attack, depression, and stroke. To avoid this, stress quantification is important for clinical intervention and disease prevention. This study aims to investigate the feasibility of exploiting electroencephalography (EEG) signals to discriminate between different stress levels. We propose a new assessment protocol whereby the stress level is represented by the complexity of mental arithmetic (MA) task for example, at three levels of difficulty, and the stressors are time pressure and negative feedback. Using 18-male subjects, the experimental results showed that there were significant differences in EEG response between the control and stress conditions at different levels of MA task with p values < 0.001. Furthermore, we found a significant reduction in alpha rhythm power from one stress level to another level, p values < 0.05. In comparison, results from self-reporting questionnaire NASA-TLX approach showed no significant differences between stress levels. In addition, we developed a discriminant analysis method based on multiclass support vector machine (SVM) with error-correcting output code (ECOC). Different stress levels were detected with an average classification accuracy of 94.79%. The lateral index (LI) results further showed dominant right prefrontal cortex (PFC) to mental stress (reduced alpha rhythm). The study demonstrated the feasibility of using EEG in classifying multilevel mental stress and reported alpha rhythm power at right prefrontal cortex as a suitable index.