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Sample records for abnormal stress test

  1. A risk score for predicting coronary artery disease in women with angina pectoris and abnormal stress test finding.

    PubMed

    Lo, Monica Y; Bonthala, Nirupama; Holper, Elizabeth M; Banks, Kamakki; Murphy, Sabina A; McGuire, Darren K; de Lemos, James A; Khera, Amit

    2013-03-15

    Women with angina pectoris and abnormal stress test findings commonly have no epicardial coronary artery disease (CAD) at catheterization. The aim of the present study was to develop a risk score to predict obstructive CAD in such patients. Data were analyzed from 337 consecutive women with angina pectoris and abnormal stress test findings who underwent cardiac catheterization at our center from 2003 to 2007. Forward selection multivariate logistic regression analysis was used to identify the independent predictors of CAD, defined by ≥50% diameter stenosis in ≥1 epicardial coronary artery. The independent predictors included age ≥55 years (odds ratio 2.3, 95% confidence interval 1.3 to 4.0), body mass index <30 kg/m(2) (odds ratio 1.9, 95% confidence interval 1.1 to 3.1), smoking (odds ratio 2.6, 95% confidence interval 1.4 to 4.8), low high-density lipoprotein cholesterol (odds ratio 2.9, 95% confidence interval 1.5 to 5.5), family history of premature CAD (odds ratio 2.4, 95% confidence interval 1.0 to 5.7), lateral abnormality on stress imaging (odds ratio 2.8, 95% confidence interval 1.5 to 5.5), and exercise capacity <5 metabolic equivalents (odds ratio 2.4, 95% confidence interval 1.1 to 5.6). Assigning each variable 1 point summed to constitute a risk score, a graded association between the score and prevalent CAD (ptrend <0.001). The risk score demonstrated good discrimination with a cross-validated c-statistic of 0.745 (95% confidence interval 0.70 to 0.79), and an optimized cutpoint of a score of ≤2 included 62% of the subjects and had a negative predictive value of 80%. In conclusion, a simple clinical risk score of 7 characteristics can help differentiate those more or less likely to have CAD among women with angina pectoris and abnormal stress test findings. This tool, if validated, could help to guide testing strategies in women with angina pectoris.

  2. Abnormal EKG stress test in rats with type 1 diabetes is deterred with low-intensity exercise programme.

    PubMed

    Smirnova, I V; Kibiryeva, N; Vidoni, E; Bunag, R; Stehno-Bittel, L

    2006-11-01

    The focus of this study was to determine whether minimal levels of exercise could halt the formation of diabetes-induced heart pathology. Seven-week-old male rats were divided into four groups: sedentary nondiabetic, exercise-trained non-diabetic, sedentary diabetic and exercise-trained diabetic. Individualised exercise programmes were based on the animal's tolerance, and continued for 7 weeks after the induction of diabetes. At the completion of the study, no differences were found in skeletal muscle citrate synthase activity between diabetic sedentary and exercise-trained rats, indicating that the exercise was low intensity. Diabetes-induced heart hypertrophy was not reversed with exercise as measured by heart-to-body weight ratios and EKG (R wave height). There was no statistical difference between groups in the response to an exercise stress test prior to the induction of diabetes. However, 4 weeks of diabetes resulted in a significant decrease in resting and post-stress test heart rates (9% and 20%, respectively), which remained depressed at week 7. The sedentary diabetic animals demonstrated an abnormal response during the recovery period of the EKG exercise test, which was not present in non-diabetic or exercise-trained diabetic animals. In conclusion, lowintensity exercise training improved the cardiac response to an exercise stress test in diabetic animals.

  3. Stress testing predischarge and six weeks after myocardial infarction to compare submaximal and maximal exercise predischarge and to assess the reproducibility of induced abnormalities.

    PubMed

    Handler, C E; Sowton, E

    1985-10-01

    Submaximal and maximal treadmill exercise tests were performed predischarge in 64 patients after acute myocardial infarction to assess the relative yield of residual ischaemic abnormalities. The reproducibility of individual abnormalities resulting from maximal stress tests performed predischarge and 6 weeks after infarction was also assessed in 55 of these patients. Compared with predischarge submaximal exercise testing, a maximal exercise test identified a significantly greater number of patients with residual myocardial ischaemia (26 vs. 15, P less than 0.05) and this was associated with a significantly longer average maximal exercise duration (P less than 0.001), and a higher rate-pressure product (P less than 0.001). Among the 55 patients who had maximal stress tests both predischarge and 6 weeks after infarction, there was a significant lack of reproducibility in the occurrence of exercise induced angina (P less than 0.01) and an abnormal blood pressure response (P less than 0.02). In contrast, exercise induced ST segment depression and elevation and ventricular arrhythmias were relatively reproducible. More patients had an ischaemic test result (ST depression or angina) at the later test compared to the predischarge test (33 vs. 25 patients) but this increase was not statistically significant. There were, however, significant increases at the later test in mean maximal exercise duration (P less than 0.001). mean maximal heart rate (P less than 0.001) and heart rate-systolic blood pressure double product (P less than 0.001). The majority of patients who had a cardiac event in the period between the two tests had a predischarge test abnormality. We conclude that a significantly greater number of patients with residual reversible myocardial ischaemia after infarction will be identified by symptom limited exercise testing compared with a submaximal predischarge test. Because ST depression and elevation appear reproducible, patients who develop these

  4. [Hypertension and stress tests].

    PubMed

    Mallion, J M; Siché, J P; de Gaudemaris, R

    1989-09-15

    Stress tests have been performed for a long time in patients with coronary disease. The study of blood pressure variations, under these circumstances, is also interesting in hypertension. Several types of stress tests, dynamic and static, may be performed. Dynamic tests on ergometric bicycles are the most frequently performed. The evolution of the BP during stress increases regularly and there is a linear correlation between the BP values and the level of work as well as the heart rate (HR). It is therefore possible to individualize a reference blood pressure profile, according to age and sex. The stress may find applications from a diagnostic, prognostic and therapeutic standpoint. First of all, in borderline HT, the stress test enables to confirm the HT and better differentiate between hyperemotional and hyperkinetic patients. In severe hypertension, the stress test permits to better define the magnitude of the haemodynamic disorder. In true hypertensive patients, undergoing major physical stress (work, sports...) the stress test permits to evaluate the tolerance to stress and the faculties of myocardial adaptation. From a prognostic standpoint, the incidence of permanent hypertension is 2 to 3 times higher in patients presenting an abnormal blood pressure profile. There is a significant correlation between the BP at maximum stress and the left ventricular mass index at all stages of the HT. The stress test makes it possible to better define the mode of action of antihypertensive medications, prescribe a personalized treatment according to these patients reactivity to stress and guarantee the correction of blood pressure abnormalities, since normalisation at rest does not necessarily imply a normalisation during stress. PMID:2686518

  5. Exercise stress test

    MedlinePlus

    Exercise ECG; ECG - exercise treadmill; EKG - exercise treadmill; Stress ECG; Exercise electrocardiography; Stress test - exercise treadmill; CAD - treadmill; Coronary artery disease - treadmill; Chest pain - treadmill; Angina - treadmill; ...

  6. Abnormal Cervical Cancer Screening Test Results

    MedlinePlus

    ... LEEP) —A thin wire loop that carries an electric current is used to remove abnormal areas of the ... the cervix using a thin wire loop and electric energy. Pap ... this document sets forth current information and opinions related to women’s health. The ...

  7. Doppler echocardiography in stress testing.

    PubMed

    Teague, S M

    1991-06-01

    Doppler ultrasound may have a role in the stress testing laboratory for the identification of patients with coronary disease through the assessment of dynamic ventricular systolic function. Quantitative systolic ejection phase indexes of maximal acceleration, peak velocity, and volume of blood ejected from the left ventricle can be obtained in the exercising patient. Trials comparing stress Doppler ultrasound with ST-segment changes, gated blood pool radionuclide or echocardiographic studies of ejection fraction or wall motion abnormality, and thallium scintigraphic perfusion defects have returned comparable or better sensitivity and specificity referencing coronary angiography. Graded treadmill exercise, stationary bicycle exercise, and pharmacological stress (dipyridamole) have been used. The normal Doppler stress response is a near linear increase in peak ejection velocity with increasing cardiac work, as reflected in heart rate. Patients with coronary artery disease show blunted augmentation of Doppler ejection dynamics between rest and peak stress, and the degree of blunting appears to be proportional to the anatomic extent of coronary disease and the magnitude of ventricular perfusion and performance impairment. Stress Doppler ultrasound achieves diagnostic power for coronary disease with ultrasonic technology, inexpensive equipment, without ionizing radiation, and few personnel.

  8. Exercise stress testing

    NASA Technical Reports Server (NTRS)

    Schuster, B.

    1975-01-01

    Positive maximum stress tests in the management of coronary patients are discussed. It is believed that coronary angiography would be the ultimate test to predict the future of patients with coronary heart disease. Progression of angina, myocardial infarction, and death due to heart disease were analyzed.

  9. Stress Corrosion Testing

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Advanced testing of structural materials was developed by Lewis Research Center and Langley Research Center working with the American Society for Testing and Materials (ASTM). Under contract, Aluminum Company of America (Alcoa) conducted a study for evaluating stress corrosion cracking, and recommended the "breaking load" method which determines fracture strengths as well as measuring environmental degradation. Alcoa and Langley plan to submit the procedure to ASTM as a new testing method.

  10. Hormonal and behavioural abnormalities induced by stress in utero: an animal model for depression.

    PubMed

    Maccari, S; Darnaudery, M; Van Reeth, O

    2001-09-01

    Prenatal stress in rats can exert profound influence on the off spring's development, inducing abnormalities such as increased "anxiety", "emotionality" or "depression-like" behaviours.Prenatal stress has long-term effects on the development of the hypothalamo-pituitary-adrenal(HPA) axis and forebrain cholinergic systems. These long-term neuroendocrinological effects are mediated, at least in part, by stress-induced maternal corticosterone increase during pregnancy and stress-induced maternal anxiety during the postnatal period. We have shown a significant phase advance in the circadian rhythms of corticosterone secretion and locomotor activity in prenatally-stressed (PNS) rats. When subjected to an abrupt shift in the light-dark(LD) cycle, PNS rats resynchronized their activity rhythm more slowly than control rats. In view of the data suggesting abnormalities in the circadian timing system in these animals, we have investigated the effects of prenatal stress on the sleep-wake cycle in adult male rats. PNS rats exhibited various changes in sleep-wake parameters, including a dramatic increase in the amount of paradoxical sleep. Taken together, our results indicate that prenatal stress can induce increased responses to stress and abnormal circadian rhythms and sleep in adult rats.Various clinical observations in humans suggest a possible pathophysiological link between depression and disturbances in circadian rhythmicity. Circadian abnormalities in depression can be related to those found in PNS rats. Interestingly, we have recently shown that the increased immobility in the forced swimming test observed in PNS rats can be corrected by chronic treatment with the antidepressant tianeptine, or with melatonin or S23478, a melatonin agonist. Those results reinforce the idea of the usefulness of PNS rats as an appropriate animal model to study human depression and support a new antidepressant-like effect of melatonin and the melatonin agonist S23478. PMID:22432138

  11. Abnormal Fear Memory as a Model for Posttraumatic Stress Disorder.

    PubMed

    Desmedt, Aline; Marighetto, Aline; Piazza, Pier-Vincenzo

    2015-09-01

    For over a century, clinicians have consistently described the paradoxical co-existence in posttraumatic stress disorder (PTSD) of sensory intrusive hypermnesia and declarative amnesia for the same traumatic event. Although this amnesia is considered as a critical etiological factor of the development and/or persistence of PTSD, most current animal models in basic neuroscience have focused exclusively on the hypermnesia, i.e., the persistence of a strong fear memory, neglecting the qualitative alteration of fear memory. The latest is characterized by an underrepresentation of the trauma in the context-based declarative memory system in favor of its overrepresentation in a cue-based sensory/emotional memory system. Combining psychological and neurobiological data as well as theoretical hypotheses, this review supports the idea that contextual amnesia is at the core of PTSD and its persistence and that altered hippocampal-amygdalar interaction may contribute to such pathologic memory. In a first attempt to unveil the neurobiological alterations underlying PTSD-related hypermnesia/amnesia, we describe a recent animal model mimicking in mice some critical aspects of such abnormal fear memory. Finally, this line of argument emphasizes the pressing need for a systematic comparison between normal/adaptive versus abnormal/maladaptive fear memory to identify biomarkers of PTSD while distinguishing them from general stress-related, potentially adaptive, neurobiological alterations.

  12. Abnormal Fear Memory as a Model for Posttraumatic Stress Disorder.

    PubMed

    Desmedt, Aline; Marighetto, Aline; Piazza, Pier-Vincenzo

    2015-09-01

    For over a century, clinicians have consistently described the paradoxical co-existence in posttraumatic stress disorder (PTSD) of sensory intrusive hypermnesia and declarative amnesia for the same traumatic event. Although this amnesia is considered as a critical etiological factor of the development and/or persistence of PTSD, most current animal models in basic neuroscience have focused exclusively on the hypermnesia, i.e., the persistence of a strong fear memory, neglecting the qualitative alteration of fear memory. The latest is characterized by an underrepresentation of the trauma in the context-based declarative memory system in favor of its overrepresentation in a cue-based sensory/emotional memory system. Combining psychological and neurobiological data as well as theoretical hypotheses, this review supports the idea that contextual amnesia is at the core of PTSD and its persistence and that altered hippocampal-amygdalar interaction may contribute to such pathologic memory. In a first attempt to unveil the neurobiological alterations underlying PTSD-related hypermnesia/amnesia, we describe a recent animal model mimicking in mice some critical aspects of such abnormal fear memory. Finally, this line of argument emphasizes the pressing need for a systematic comparison between normal/adaptive versus abnormal/maladaptive fear memory to identify biomarkers of PTSD while distinguishing them from general stress-related, potentially adaptive, neurobiological alterations. PMID:26238378

  13. What Is Stress Testing?

    MedlinePlus

    ... your heart isn't getting enough blood during exercise: Abnormal changes in your heart rate or blood pressure Symptoms such as shortness of breath or chest pain, especially if they occur at low levels of exercise Abnormal changes in your heart's rhythm or electrical ...

  14. [The general practitioner and abnormal liver function tests].

    PubMed

    Hallez, R

    1997-09-01

    In case of abnormal liver function tests, it's necessary to distinguish different situations, starting from this first data. We will successively consider: the high and moderate acute increases of aminotransferase, the chronic increases of aminotransferase, the isolated cholestase picture and the isolated increases of gamma GT or of bilirubine. We will finish with a partial survey about drug-induced liver diseases.

  15. Chronic stress does not further exacerbate the abnormal psychoneuroendocrine phenotype of Cbg-deficient male mice.

    PubMed

    de Medeiros, Gabriela F; Minni, Amandine M; Helbling, Jean-Christophe; Moisan, Marie-Pierre

    2016-08-01

    Chronic stress leads to a dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis which can constitute a base for pathophysiological consequences. Using mice totally deficient in Corticosteroid binding globulin (CBG), we have previously demonstrated the important role of CBG in eliciting an adequate response to an acute stressor. Here, we have studied its role in chronic stress situations. We have submitted Cbg ko and wild-type (WT) male mice to two different chronic stress paradigms - the unpredictable chronic mild stress and the social defeat. Then, their impact on neuroendocrine function - through corticosterone and CBG measurement - and behavioral responses - via anxiety and despair-like behavioral tests - was evaluated. Both chronic stress paradigms increased the display of despair-like behavior in WT mice, while that from Cbg ko mice - which was already high - was not aggravated. We have also found that control and defeated (stressed) Cbg ko mice show no difference in the social interaction test, while defeated WT mice reduce their interaction time when compared to unstressed WT mice. Interestingly, the same pattern was observed for corticosterone levels, where both chronic stress paradigms lowered the corticosterone levels of WT mice, while those from Cbg ko mice remained low and unaltered. Plasma CBG binding capacity remained unaltered in WT mice regardless of the stress paradigm. Through the use of the Cbg ko mice, which only differs genetically from WT mice by the absence of CBG, we demonstrated that CBG is crucial in modulating the effects of stress on plasma corticosterone levels and consequently on behavior. In conclusion, individuals with CBG deficiency, whether genetically or environmentally-induced, are vulnerable to acute stress but do not have their abnormal psychoneuroendocrine phenotype further affected by chronic stress.

  16. Stressed Kevlar strand test

    SciTech Connect

    Golopol, H.; Clarkson, J.; Moore, R.; Hetherington, N.

    1981-09-10

    Kevlar is a polyaramid fiber used in fiber composites. In order to characterize this material, we determined the effect of time, temperature, and chemical environment on the strength retention of stressed Kevlar strands. In this work, we applied a stress load of 20% of the ultimate tensile strength (UTS). Strands were hung with a suitable weight in a closed container. Each container was then provided with its own heater and chemical environment. No significant loss of strength retention was found on these stressed strands. 4 figures, 5 tables.

  17. Abnormal Head Impulse Test in a Unilateral Cerebellar Lesion

    PubMed Central

    Baek, Seol-Hee; Jung, Jin-Man; Kwon, Do-Young; Park, Moon Ho; Choi, June; Kim, Ji-Soo

    2015-01-01

    Background The findings of head impulse tests (HIT) are usually normal in cerebellar lesions. Case Report A 46-year-old male presented with progressive dizziness and imbalance of 3 weeks duration. The patient exhibited catch-up saccades during bedside horizontal HIT to either side, which was more evident during the rightward HIT. However, results of bithermal caloric tests and rotatory chair test were normal. MRI revealed a lesion in the inferior cerebellum near the flocculus. Conclusions This case provides additional evidence that damage to the flocculus or its connections may impair the vestibulo-ocular reflex only during high-speed stimuli, especially when the stimuli are applied to the contralesional side. By observing accompanying cerebellar signs, the abnormal HIT findings caused by a cerebellar disorder can be distinguished from those produced by peripheral vestibular disorders. PMID:25749819

  18. Behavioral, Neurochemical and Neuroendocrine Effects of Abnormal Savda Munziq in the Chronic Stress Mice

    PubMed Central

    Amat, Nurmuhammat; Hoxur, Parida; Ming, Dang; Matsidik, Aynur; Kijjoa, Anake; Upur, Halmurat

    2012-01-01

    Oral administration of Abnormal Savda Munsiq (ASMq), a herbal preparation used in Traditional Uighur Medicine, was found to exert a memory-enhancing effect in the chronic stressed mice, induced by electric foot-shock. The memory improvement of the stressed mice was shown by an increase of the latency time in the step-through test and the decrease of the latency time in the Y-maze test. Treatment with ASMq was found to significantly decrease the serum levels of adrenocorticotropic hormone (ACTH), corticosterone (CORT) and β-endorphin (β-EP) as well as the brain and serum level of norepinephrine (NE). Furthermore, ASMq was able to significantly reverse the chronic stress by decreasing the brain and serum levels of the monoamine neurotransmitters dopamine (DA), 5-hydroxytryptamine (5-HT) and 3,4-dihydroxyphenylalanine (DOPAC). The results obtained from this study suggested that the memory-enhancing effect of ASMq was mediated through regulations of neurochemical and neuroendocrine systems. PMID:22919413

  19. Nuclear stress test

    MedlinePlus

    ... you exercise. Your blood pressure and heart rhythm ( ECG ) will be watched throughout the test. When your ... have symptoms or changes in blood pressure, your ECG or the images of your heart that caused ...

  20. Computer-enhanced thallium scintigrams in asymptomatic men with abnormal exercise tests

    SciTech Connect

    Uhl, G.S.; Kay, T.N.; Hickman, J.R. Jr.

    1981-12-01

    The use of treadmill testing in asymptomatic patients and those with an atypical chest pain syndrome is increasing, yet the proportion of false positive stress electrocardiograms increases as the prevalence of disease decreases. To determine the diagnostic accuracy of computer-enhanced thallium perfusion scintigraphy in this subgroup of patients, multigated thallium scans were obtained after peak exercise and 3 or 4 hours after exercise and the raw images enhanced by a computer before interpretations were made. The patient group consisted of 191 asymptomatic U.S. Air force aircrewmen who had an abnormal exercise electrocardiogram. Of these, 135 had normal coronary angiographic findings, 15 had subcritical coronary stenosis (less than 50 percent diameter narrowing) and 41 had significant coronary artery disease. Use of computer enhancement resulted in only four false positive and two false negative scintigrams. The small subgroup with subcritical coronary disease had equivocal results on thallium scintigraphy, 10 men having abnormal scans and 5 showing no defects. The clinical significance of such subcritical disease in unclear, but it can be detected with thallium scintigraphy. Thallium scintigrams that have been enhanced by readily available computer techniques are an accurate diagnostic tool even in asymptomatic patients with an easily interpretable abnormal maximal stress electrocardiogram. Thallium scans can be effectively used in counseling asymptomatic patients on the likelihood of their having coronary artery disease.

  1. Low yield of unselected testing in patients with acutely abnormal liver function tests

    PubMed Central

    Chadwick, Andrew

    2015-01-01

    Objectives To audit the diagnostic yield and cost implications of the use of a ‘liver screen’ for inpatients with abnormal liver function tests. Design We performed a retrospective audit of inpatients with abnormal liver function tests. We analysed all investigations ordered including biochemistry, immunology, virology and radiology. The final diagnosis was ascertained in each case, and the diagnostic yield and cost per positive diagnosis for each investigation were calculated. Setting St Thomas’ NHS Trust. Participants All inpatients investigated for abnormal liver function tests over a 12-month period. Main outcome measures We calculated the percentage of courses due to each diagnosis, the yield of each investigation and the cost per positive diagnosis for each investigation. Results A total of 308 patients were included, and a final diagnosis was made in 224 patients (73%) on the basis of both clinical data and investigations. There was considerable heterogeneity in the tests included in an acute liver screen. History and ultrasound yielded the most diagnoses (40% and 30%, respectively). The yield of autoimmune and metabolic screens was minimal. Conclusions Our results demonstrate the low yield of unselected testing in patients with abnormal liver function tests. A thorough history, ultrasound and testing for blood-borne viruses are the cornerstones of diagnosis. Specialist input should be sought before further testing. Prospective studies to evaluate the yield and cost-effectiveness of different testing strategies are needed. PMID:26770816

  2. Wall shear stress indicators in abnormal aortic geometries

    NASA Astrophysics Data System (ADS)

    Prahl Wittberg, Lisa; van Wyk, Stevin; Fuchs, Laszlo; Gutmark, Ephraim; Gutmark-Little, Iris

    2015-11-01

    Cardiovascular disease, such as atherosclerosis, occurs at specific locations in the arterial tree. Characterizing flow and forces at these locations is crucial to understanding the genesis of disease. Measures such as time average wall shear stress, oscillatory shear index, relative residence time and temporal wall shear stress gradients have been shown to identify plaque prone regions. The present paper examines these indices in three aortic geometries obtained from patients whose aortas are deformed due to a genetic pathology and compared to one normal geometry. This patient group is known to be prone to aortic dissection and our study aims to identify early indicators that will enable timely intervention. Data obtained from cardiac magnetic resonance imaging is used to reconstruct the aortic arch. The local unsteady flow characteristics are calculated, fully resolving the flow field throughout the entire cardiac cycle. The Quemada model is applied to account for the non-Newtonian properties of blood, an empirical model valid for different red blood cell loading. The impact of the deformed aortic geometries is analyzed to identify flow patterns that could lead to arterial disease at certain locations.

  3. Identification of an abnormal beryllium lymphocyte proliferation test.

    PubMed

    Frome, Edward L; Newman, Lee S; Cragle, Donna L; Colyer, Shirley P; Wambach, Paul F

    2003-02-01

    The potential hazards from exposure to beryllium or beryllium compounds in the workplace were first reported in the 1930s. The tritiated thymidine beryllium lymphocyte proliferation test (BeLPT) is an in vitro blood test that is widely used to screen beryllium exposed workers in the nuclear industry for sensitivity to beryllium. The clinical significance of the BeLPT was described and a standard protocol was developed in the late 1980s. Cell proliferation is measured by the incorporation of tritiated thymidine into dividing cells on two culture dates and using three concentrations of beryllium sulfate. Results are expressed as a 'stimulation index' (SI) which is the ratio of the amount of tritiated thymidine (measured by beta counts) in the simulated cells divided by the counts for the unstimulated cells on the same culture day. Several statistical methods for use in the routine analysis of the BeLPT were proposed in the early 1990s. The least absolute values (LAV) method was recommended for routine analysis of the BeLPT. This report further evaluates the LAV method using new data, and proposes a new method for identification of an abnormal or borderline test. This new statistical-biological positive (SBP) method reflects the clinical judgment that: (i) at least two SIs show a 'positive' response to beryllium; and (ii) that the maximum of the six SIs must exceed a cut-point that is determined from a reference data set of normal individuals whose blood has been tested by the same method in the same serum. The new data is from the Y-12 National Security Complex in Oak Ridge (Y-12) and consists of 1080 workers and 33 non-exposed control BeLPTs (all tested in the same serum). Graphical results are presented to explain the statistical method, and the new SBP method is applied to the Y-12 group. The true positive rate and specificity of the new method were estimated to be 86% and 97%, respectively. An electronic notebook that is accessible via the Internet was used in

  4. Membrane Degradation Accelerated Stress Test

    SciTech Connect

    Mukundan, Rangachary; Borup, Rodney L.

    2015-01-21

    These are a set of slides that deal with membrane degradation accelerated stress test. Specifically, the following topics are covered: membrane degradation FCTT drive cycle; membrane ASTs; current membrane ASTs damage mechanisms; proposed membrane AST, RH cycling in H2/Air; current proposed AST; 2min/2min AST damage mechanism; 30sec/45sec RH cycling at OCV.

  5. A causal model of post-traumatic stress disorder: disentangling predisposed from acquired neural abnormalities.

    PubMed

    Admon, Roee; Milad, Mohammed R; Hendler, Talma

    2013-07-01

    Discriminating neural abnormalities into the causes versus consequences of psychopathology would enhance the translation of neuroimaging findings into clinical practice. By regarding the traumatic encounter as a reference point for disease onset, neuroimaging studies of post-traumatic stress disorder (PTSD) can potentially allocate PTSD neural abnormalities to either predisposing (pre-exposure) or acquired (post-exposure) factors. Based on novel research strategies in PTSD neuroimaging, including genetic, environmental, twin, and prospective studies, we provide a causal model that accounts for neural abnormalities in PTSD, and outline its clinical implications. Current data suggest that abnormalities within the amygdala and dorsal anterior cingulate cortex represent predisposing risk factors for developing PTSD, whereas dysfunctional hippocampal-ventromedial prefrontal cortex (vmPFC) interactions may become evident only after having developed the disorder.

  6. Mutations in the SPTLC1 protein cause mitochondrial structural abnormalities and endoplasmic reticulum stress in lymphoblasts.

    PubMed

    Myers, Simon J; Malladi, Chandra S; Hyland, Ryan A; Bautista, Tara; Boadle, Ross; Robinson, Phillip J; Nicholson, Garth A

    2014-07-01

    Mutations in serine palmitoyltransferase long chain subunit 1 (SPTLC1) cause the typical length-dependent axonal degeneration hereditary sensory neuropathy type 1 (HSN1). Transmission electron microscopy studies on SPTLC1 mutant lymphoblasts derived from patients revealed specific structural abnormalities of mitochondria. Swollen mitochondria with abnormal cristae were clustered around the nucleus, with some mitochondria being wrapped in rough endoplasmic reticulum (ER) membranes. Total mitochondrial counts revealed a significant change in mitochondrial numbers between healthy and diseased lymphocytes but did not reveal any change in length to width ratios nor were there any changes to cellular function. However, there was a notable change in ER homeostasis, as assessed using key ER stress markers, BiP and ERO1-Lα, displaying reduced protein expression. The observations suggest that SPTLC1 mutations cause mitochondrial abnormalities and ER stress in HSN1 cells. PMID:24673574

  7. Estimation of stress relaxation time for normal and abnormal breast phantoms using optical technique

    NASA Astrophysics Data System (ADS)

    Udayakumar, K.; Sujatha, N.

    2015-03-01

    Many of the early occurring micro-anomalies in breast may transform into a deadliest cancer tumor in future. Probability of curing early occurring abnormalities in breast is more if rightly identified. Even in mammogram, considered as a golden standard technique for breast imaging, it is hard to pick up early occurring changes in the breast tissue due to the difference in mechanical behavior of the normal and abnormal tissue when subjected to compression prior to x-ray or laser exposure. In this paper, an attempt has been made to estimate the stress relaxation time of normal and abnormal breast mimicking phantom using laser speckle image correlation. Phantoms mimicking normal breast is prepared and subjected to precise mechanical compression. The phantom is illuminated by a Helium Neon laser and by using a CCD camera, a sequence of strained phantom speckle images are captured and correlated by the image mean intensity value at specific time intervals. From the relation between mean intensity versus time, tissue stress relaxation time is quantified. Experiments were repeated for phantoms with increased stiffness mimicking abnormal tissue for similar ranges of applied loading. Results shows that phantom with more stiffness representing abnormal tissue shows uniform relaxation for varying load of the selected range, whereas phantom with less stiffness representing normal tissue shows irregular behavior for varying loadings in the given range.

  8. Abnormal test growth in benthic foraminifera from hypersaline coastal ponds of the United Arab Emirates

    NASA Astrophysics Data System (ADS)

    Fiorini, Flavia; Lokier, Stephen W.

    2014-05-01

    The living (Rose-Bengal stained) benthic foraminifera assemblage from shallow coastal ponds located in the intertidal area of the United Arab Emirate Western Region was investigated. The studied coastal ponds are located between a lagoonal area, characterized by carbonate sedimentation, and the supratidal, evaporite-dominated, sabkha. Sampling was undertaken when the maximum water depth in the ponds was 50 cm with a water temperature ranging from 27 to 35°C, a pH of 8 and a maximum salinity of 60 ppt. The sides and floor of the pond were characterized by a microbial mat. Detached blades of sea grass were present in the ponds and are inferred to have been transported into the pond either during high-tides or storm surges. Collected samples were stained with Rose-Bengal at the moment of sample collection and the living assemblage was studied. The benthic foraminifera that were present show a low-diversity assemblage. Epiphytic larger benthic foraminifera dominate the living assemblage with Peneroplis pertusus and P. planatus characterizing 90% of the living assemblage and the species Spirolina areatina, S. aciculata, Sorites marginalis and Quinqueloculina spp. comprising the rest of the foraminifera community. High percentages (up to 50% of the stained assemblage) of anomalous tests of benthic foraminifera belonging to the genera Peneroplis, Spirolina and Sorites were observed. The anomalies included dissolution, microboring and abnormality in growth. Three different forms of abnormal shell architecture were recorded; the presence of multiple apertures with reduced size, deformation in the general shape of the test and abnormal coiling. The high percentage of abnormal tests reflects natural environmental stress caused by instability of physical parameters (particularly high and variable salinity and temperature) in this kind of transitional marine environment. The unique presence of epiphytic species, suggests that epiphytic foraminifera may be transported into the

  9. Chromosomal abnormalities & oxidative stress in women with premature ovarian failure (POF)

    PubMed Central

    Kumar, Manoj; Pathak, Dhananjay; Venkatesh, Sundararajan; Kriplani, Alka; Ammini, A.C.; Dada, Rima

    2012-01-01

    Background & objectives: Premature ovarian failure (POF) is defined as the cessation of ovarian function under the age of 40 yr and is characterized by amenorrhoea, hypoestrogenism and elevated serum gonadotrophin levels. The cause of POF remains undetermined in majority of the cases. This study was aimed to investigate the type and frequency of cytogenetic abnormalities in patients with idiopathic POF and also to study the role of oxidative stress in such cases. Methods: Seventy five women with idiopathic POF were included in this study. Chromosome analysis was done in peripheral blood lymphocytes by conventional GTG banding to identify numerical or structural abnormalities. Cytogenetically normal cases were investigated for reactive oxygen species (ROS) levels in their blood by luminol-chemiluminescence assay. Results: Eighteen chromosomal anomalies were identified in POF patients (24%). Majority of the cases were found to have X-chromosome abnormalities (28%). Overall median ROS range was found to be significantly higher (P<0.01) in POF patients [50480 (120,132966) RLU/min] compared to controls [340 (120,5094) RLU/min]. Among these, 50 per cent of the POF patients had higher ROS levels, 20 per cent had medium elevation and 30 per cent were found to have normal values comparable to controls. Interpretation & conclusions: X-chromosome anomalies were found to be the major contributor of POF. Oxidative stress may be the underlying aetiology in idiopathic premature ovarian failure. Thus the results of this study highlight the role of cytogenetic abnormalities and supraphysiological levels of ROS in causation of idiopathic POF. But the role of oxidative stress needs to be confirmed by other studies on patients from different geographical areas and from different ethnicities. PMID:22382189

  10. Abnormal ventilation scans in middle-aged smokers. Comparison with tests of overall lung function

    SciTech Connect

    Barter, S.J.; Cunningham, D.A.; Lavender, J.P.; Gibellino, F.; Connellan, S.J.; Pride, N.B.

    1985-07-01

    The uniformity of regional ventilation during tidal breathing has been assessed using continuous inhalation of krypton-81m in 43 male, lifelong nonsmokers and 46 male, current cigarette smokers (mean daily consumption 24.1 cigarettes/day) between 44 and 61 yr of age and with mild or no respiratory symptoms. All subjects had normal chest radiographs. The results of the ventilation scans were compared with tests of overall lung function (spirometry, maximal expiratory flow-volume curves, and single-breath N2 test). Diffuse abnormalities of the ventilation scan were found in 19 (41%) of the 46 smokers but in none of the nonsmokers. Focal abnormalities were found in 7 smokers and 3 nonsmokers. Smokers showed the expected abnormalities in overall lung function (reduced FEV1 and VC, increased single-breath N2 slope, and closing volume), but in individual smokers there was only a weak relation between the severity of abnormality of overall lung function and an abnormal ventilation scan. Abnormal scans could be found when overall lung function was normal and were not invariably found when significant abnormalities in FEV1/VC or N2 slope were present. There was no relation between the presence of chronic expectoration and an abnormal scan. The prognostic significance of an abnormal ventilation scan in such smokers remains to be established.

  11. Stress Testing of Data-Communication Networks

    NASA Technical Reports Server (NTRS)

    Leucht, Kurt; Bedette, Guy

    2006-01-01

    NetStress is a computer program that stress-tests a data-communication network and components thereof. NetStress comprises two components running, respectively, in a transmitting system and a receiving system connected to a network under test

  12. Abnormal Liver Function Tests in an Anorexia Nervosa Patient and an Atypical Manifestation of Refeeding Syndrome

    PubMed Central

    Vootla, Vamshidhar R.; Daniel, Myrta

    2015-01-01

    Refeeding syndrome is defined as electrolyte and fluid abnormalities that occur in significantly malnourished patients when they are refed orally, enterally, or parenterally. The principal manifestations include hypophosphatemia, hypokalemia, vitamin deficiencies, volume overload and edema. This can affect multiple organ systems, such as the cardiovascular, pulmonary, or neurological systems, secondary to the above-mentioned abnormalities. Rarely, patients may develop gastrointestinal symptoms and show abnormal liver function test results. We report the case of a 52-year-old woman with anorexia nervosa who developed refeeding syndrome and simultaneous elevations of liver function test results, which normalized upon the resolution of the refeeding syndrome. PMID:26351414

  13. Abnormal Liver Function Tests in an Anorexia Nervosa Patient and an Atypical Manifestation of Refeeding Syndrome.

    PubMed

    Vootla, Vamshidhar R; Daniel, Myrta

    2015-01-01

    Refeeding syndrome is defined as electrolyte and fluid abnormalities that occur in significantly malnourished patients when they are refed orally, enterally, or parenterally. The principal manifestations include hypophosphatemia, hypokalemia, vitamin deficiencies, volume overload and edema. This can affect multiple organ systems, such as the cardiovascular, pulmonary, or neurological systems, secondary to the above-mentioned abnormalities. Rarely, patients may develop gastrointestinal symptoms and show abnormal liver function test results. We report the case of a 52-year-old woman with anorexia nervosa who developed refeeding syndrome and simultaneous elevations of liver function test results, which normalized upon the resolution of the refeeding syndrome.

  14. Response to an abnormal ovarian cancer-screening test result: test of the social cognitive processing and cognitive social health information processing models.

    PubMed

    Andrykowski, Michael A; Pavlik, Edward J

    2011-04-01

    All cancer screening tests produce a proportion of abnormal results requiring follow up. Consequently, the cancer-screening setting is a natural laboratory for examining psychological and behavioural response to a threatening health-related event. This study tested hypotheses derived from the social cognitive processing and cognitive-social health information processing models in trying to understand response to an abnormal ovarian cancer (OC) screening test result. Women (n = 278) receiving an abnormal screening test result a mean of 7 weeks earlier were assessed prior to a repeat screening test intended to clarify their previous abnormal result. Measures of disposition (optimism, informational coping style), social environment (social support and constraint), emotional processing, distress, and benefit finding were obtained. Regression analyses indicated greater distress was associated with greater social constraint and emotional processing and a monitoring coping style in women with a family history of OC. Distress was unrelated to social support. Greater benefit finding was associated with both greater social constraint and support and greater distress. The primacy of social constraint in accounting for both benefit finding and distress was noteworthy and warrants further research on the role of social constraint in adaptation to stressful events.

  15. Abnormal ovarian cancer screening test result: women's informational, psychological and practical needs.

    PubMed

    Ryan, Patricia Y; Graves, Kristi D; Pavlik, Edward J; Andrykowski, Michael A

    2007-01-01

    Considerable effort has been devoted to the identification of cost-effective approaches to screening for ovarian cancer (OC). Transvaginal ultrasound (TVS) is one such screening approach. Approximately 5-7% of routine TVS screening tests yield abnormal results. Some women experience significant distress after receipt of an abnormal TVS screening test. Four focus groups provided in-depth, qualitative data regarding the informational, psychological, and practical needs of women after the receipt of an abnormal TVS result. Through question and content analytic procedures, we identified four themes: anticipation, emotional response, role of the screening technician, and impact of prior cancer experiences. Results provide initial guidance toward development of interventions to promote adaptive responses after receipt of an abnormal cancer screening test result.

  16. The value of Bayes' theorem for interpreting abnormal test scores in cognitively healthy and clinical samples.

    PubMed

    Gavett, Brandon E

    2015-03-01

    The base rates of abnormal test scores in cognitively normal samples have been a focus of recent research. The goal of the current study is to illustrate how Bayes' theorem uses these base rates--along with the same base rates in cognitively impaired samples and prevalence rates of cognitive impairment--to yield probability values that are more useful for making judgments about the absence or presence of cognitive impairment. Correlation matrices, means, and standard deviations were obtained from the Wechsler Memory Scale--4th Edition (WMS-IV) Technical and Interpretive Manual and used in Monte Carlo simulations to estimate the base rates of abnormal test scores in the standardization and special groups (mixed clinical) samples. Bayes' theorem was applied to these estimates to identify probabilities of normal cognition based on the number of abnormal test scores observed. Abnormal scores were common in the standardization sample (65.4% scoring below a scaled score of 7 on at least one subtest) and more common in the mixed clinical sample (85.6% scoring below a scaled score of 7 on at least one subtest). Probabilities varied according to the number of abnormal test scores, base rates of normal cognition, and cutoff scores. The results suggest that interpretation of base rates obtained from cognitively healthy samples must also account for data from cognitively impaired samples. Bayes' theorem can help neuropsychologists answer questions about the probability that an individual examinee is cognitively healthy based on the number of abnormal test scores observed.

  17. Oxidative stress contributes to abnormal glucose metabolism and insulin sensitivity in two hyperlipidemia models

    PubMed Central

    Bai, Jiefei; Zheng, Shuang; Jiang, Dongdong; Han, Tingting; Li, Yangxue; Zhang, Yao; Liu, Wei; Cao, Yunshan; Hu, Yaomin

    2015-01-01

    Objective: Lipid metabolism disturbance can result in insulin resistance and glucose intolerance; however, the features of glucose metabolism are still elusive in different dyslipidemia. Our study intended to explore the characteristics and molecular mechanisms of glucose metabolism abnormal in hypercholesterolemia and hypertriglyceridemia models. Methods: Two mouse models were used in this study, one was lipoprotein lipase gene-deleted (LPL+/-) mice, and the other was high fat dietary (HFD) mice. Levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein-cholesterin (HDL-c) and low-density lipoprotein-cholesterin (LDL-c) in serum were measured by full-automatic biochemical analyzer. Intraperitoneal glucose tolerance test (IPGTT) was performed to evaluate insulin sensitivity and β-cell function. Malondialdehyde (MDA) and total superoxide dismutase (T-SOD) levels in serum were measured by colorimetric determination. mRNA expression of superoxide dismutase 1 (SOD1), catalase (CAT), glutathione peroxidase 1 (Gpx1), nuclear factor erythroid 2-related factor 2 (Nrf2a) and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) in liver, skeletal muscle, visceral fat and subcutaneous fat were measured by Real-Time PCR. Results: Compared with HFD mice, the levels of serum TG were significantly higher in LPL+/- mice, whereas the levels of TC, HDL-c, LDL-c were significantly lower. The plasma glucose levels were increased at each time point of intra-peritoneal glucose tolerance test (IPGTT) in both groups. Furthermore, the level of serum fasting insulin and homeostasis model assessment index-insulin resistance (HOMA-IR) increased with a decreased ISI in both groups. In addition, the plasma MDA of HFD group was higher than that of lipoprotein lipase-deficiency (LPL+/-) group, while the activity of T-SOD in HFD group was lower than that in LPL+/- group. Real-Time PCR revealed that the expressions of SOD1, CAT and Gpx1 in liver and

  18. Pathways of abnormal stress-induced Ca2+ influx into dystrophic mdx cardiomyocytes

    PubMed Central

    Fanchaouy, M.; Polakova, E.; Jung, C.; Ogrodnik, J.; Shirokova, N.; Niggli, E.

    2009-01-01

    In Duchenne muscular dystrophy, deficiency of the cytoskeletal protein dystrophin leads to well-described defects in skeletal muscle, but also to dilated cardiomyopathy, accounting for about 20% of the mortality. Mechanisms leading to cardiomyocyte cell death and cardiomyopathy are not well understood. One hypothesis suggests that the lack of dystrophin leads to membrane instability during mechanical stress and to activation of Ca2+ entry pathways. Using cardiomyocytes isolated from dystrophic mdx mice we dissected the contribution of various putative Ca2+ influx pathways with pharmacological tools. Cytosolic Ca2+ and Na+ signals as well as uptake of membrane impermeant compounds were monitored with fluorescent indicators using confocal microscopy and photometry. Membrane stress was applied as moderate osmotic challenges while membrane current was quantified using the whole-cell patch-clamp technique. Our findings suggest a major contribution of two primary Ca2+ influx pathways, stretch-activated membrane channels and short-lived microruptures. Furthermore, we found evidence for a secondary Ca2+ influx pathway, the Na+-Ca2+ exchange (NCX), which in cardiac muscle has a large transport capacity. After stress it contributes to Ca2+ entry in exchange for Na+ which had previously entered via primary stress-induced pathways, representing a previously not recognized mechanism contributing to subsequent cellular damage. This complexity needs to be considered when targeting abnormal Ca2+ influx as a treatment option for dystrophy. PMID:19604578

  19. Dobutamine "stress" test and latent cardiac susceptibility to inhaled diesel exhaust in normal and hypertensive rats**

    EPA Science Inventory

    Background -Exercise "stress" testing is a screening tool used to determine the amount of stress for which the heart can compensate before developing abnormal rhythm or ischemia, particularly in susceptible people. Although this approach has been used to assess risk in humans exp...

  20. 77 FR 16484 - Annual Stress Test

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-21

    ... in the ] proposed rule.\\2\\ Please submit your comments using only one method. \\2\\ See 77 FR 3166... CORPORATION 12 CFR Part 325 RIN 3064-AD91 Annual Stress Test AGENCY: Federal Deposit Insurance Corporation... Corporation with total consolidated assets of more than $10 billion to conduct annual stress tests. \\1\\...

  1. Characterization of abnormal wall shear stress using 4D flow MRI in human bicuspid aortopathy

    PubMed Central

    van Ooij, Pim; Potters, Wouter V.; Collins, Jeremy; Carr, Maria; Carr, James; Malaisrie, S. Chris; Fedak, Paul W.M.; McCarthy, Patrick M.; Markl, Michael; Barker, Alex J.

    2014-01-01

    There exists considerable controversy surrounding the timing and extent of aortic resection for patients with BAV disease. Since abnormal wall shear stress (WSS) is potentially associated with tissue remodeling in BAV-related aortopathy, we propose a methodology that creates patient-specific ‘heat maps’ of abnormal WSS, based on 4D flow MRI. The heat maps were created by detecting outlier measurements from a volumetric 3D map of ensemble-averaged WSS in healthy controls. 4D flow MRI was performed in 13 BAV patients, referred for aortic resection and 10 age-matched controls. Systolic WSS was calculated from this data, and an ensemble-average and standard deviation (SD) WSS map of the controls was created. Regions of the individual WSS maps of the BAV patients that showed a higher WSS than the mean+1.96SD of the ensemble-average control WSS map were highlighted. Elevated WSS was found on the greater ascending aorta (35% ± 15 of the surface area), which correlated significantly with peak systolic velocity (R2=0.5, P=0.01) and showed good agreement with the resected aortic regions. This novel approach to characterize regional aortic WSS may allow clinicians to gain unique insights regarding the heterogeneous expression of aortopathy and may be leveraged to guide patient-specific resection strategies for aorta repair. PMID:25118671

  2. Abnormal functional architecture of amygdala-centered networks in adolescent posttraumatic stress disorder.

    PubMed

    Aghajani, Moji; Veer, Ilya M; van Hoof, Marie-José; Rombouts, Serge A R B; van der Wee, Nic J; Vermeiren, Robert R J M

    2016-03-01

    Posttraumatic stress disorder (PTSD) is a prevalent, debilitating, and difficult to treat psychiatric disorder. Very little is known of how PTSD affects neuroplasticity in the developing adolescent brain. Whereas multiple lines of research implicate amygdala-centered network dysfunction in the pathophysiology of adult PTSD, no study has yet examined the functional architecture of amygdala subregional networks in adolescent PTSD. Using intrinsic functional connectivity analysis, we investigated functional connectivity of the basolateral (BLA) and centromedial (CMA) amygdala in 19 sexually abused adolescents with PTSD relative to 23 matched controls. Additionally, we examined whether altered amygdala subregional connectivity coincides with abnormal grey matter volume of the amygdaloid complex. Our analysis revealed abnormal amygdalar connectivity and morphology in adolescent PTSD patients. More specifically, PTSD patients showed diminished right BLA connectivity with a cluster including dorsal and ventral portions of the anterior cingulate and medial prefrontal cortices (p < 0.05, corrected). In contrast, PTSD patients showed increased left CMA connectivity with a cluster including the orbitofrontal and subcallosal cortices (p < 0.05, corrected). Critically, these connectivity changes coincided with diminished grey matter volume within BLA and CMA subnuclei (p < 0.05, corrected), with CMA connectivity shifts additionally relating to more severe symptoms of PTSD. These findings provide unique insights into how perturbations in major amygdalar circuits could hamper fear regulation and drive excessive acquisition and expression of fear in PTSD. As such, they represent an important step toward characterizing the neurocircuitry of adolescent PTSD, thereby informing the development of reliable biomarkers and potential therapeutic targets.

  3. Characterization of abnormal wall shear stress using 4D flow MRI in human bicuspid aortopathy.

    PubMed

    van Ooij, Pim; Potters, Wouter V; Collins, Jeremy; Carr, Maria; Carr, James; Malaisrie, S Chris; Fedak, Paul W M; McCarthy, Patrick M; Markl, Michael; Barker, Alex J

    2015-06-01

    There exists considerable controversy surrounding the timing and extent of aortic resection for patients with BAV disease. Since abnormal wall shear stress (WSS) is potentially associated with tissue remodeling in BAV-related aortopathy, we propose a methodology that creates patient-specific 'heat maps' of abnormal WSS, based on 4D flow MRI. The heat maps were created by detecting outlier measurements from a volumetric 3D map of ensemble-averaged WSS in healthy controls. 4D flow MRI was performed in 13 BAV patients, referred for aortic resection and 10 age-matched controls. Systolic WSS was calculated from this data, and an ensemble-average and standard deviation (SD) WSS map of the controls was created. Regions of the individual WSS maps of the BAV patients that showed a higher WSS than the mean + 1.96SD of the ensemble-average control WSS map were highlighted. Elevated WSS was found on the greater ascending aorta (35% ± 15 of the surface area), which correlated significantly with peak systolic velocity (R (2) = 0.5, p = 0.01) and showed good agreement with the resected aortic regions. This novel approach to characterize regional aortic WSS may allow clinicians to gain unique insights regarding the heterogeneous expression of aortopathy and may be leveraged to guide patient-specific resection strategies for aorta repair. PMID:25118671

  4. Abnormality of the corpus callosum in coalmine gas explosion-related posttraumatic stress disorder.

    PubMed

    Zhang, Yang; Li, Huabing; Lang, Xu; Zhuo, Chuanjun; Qin, Wen; Zhang, Quan

    2015-01-01

    Abnormal corpus callosum (CC) has been reported in childhood trauma-related posttraumatic stress disorder (PTSD); however, the nature of white matter (WM) integrity alterations in the CC of young adult-onset PTSD patients is unknown. In this study, 14 victims of a coal mine gas explosion with PTSD and 23 matched coal miners without experiencing the coal mine explosion were enrolled. The differences in fractional anisotropy (FA) within 7 sub-regions of the CC were compared between the two groups. Compared to the controls, PTSD coal miners exhibited significantly reduced FA values in the anterior sub-regions of the CC (P < 0.05, Bonferroni-corrected), which mainly interconnect the bilateral frontal cortices. Our findings indicated that the anterior part of the CC was more severely impaired than the posterior part in young adult-onset PTSD, which suggested the patterns of CC impairment may depend on the developmental stage of the structure when the PTSD occurs.

  5. Residual Stress Testing of Outer 3013 Containers

    SciTech Connect

    Dunn, K.

    2004-02-12

    A Gas Tungsten Arc Welded (GTAW) outer 3013 container and a laser welded outer 3013 container have been tested for residual stresses according to the American Society for Testing Materials (ASTM) Standard G-36-94 [1]. This ASTM standard describes a procedure for conducting stress-corrosion cracking tests in boiling magnesium chloride (MgCl2) solution. Container sections in both the as-fabricated condition as well as the closure welded condition were evaluated. Significantly large residual stresses were observed in the bottom half of the as-fabricated container, a result of the base to can fabrication weld because through wall cracks were observed perpendicular to the weld. This observation indicates that regardless of the closure weld technique, sufficient residual stresses exist in the as-fabricated container to provide the stress necessary for stress corrosion cracking of the container, at the base fabrication weld. Additionally, sufficiently high residual stresses were observed in both the lid and the body of the GTAW as well as the laser closure welded containers. The stresses are oriented perpendicular to the closure weld in both the container lid and the container body. Although the boiling MgCl2 test is not a quantitative test, a comparison of the test results from the closure welds shows that there are noticeably more through wall cracks in the laser closure welded container than in the GTAW closure welded container.

  6. Liver Function Test Abnormalities in Patients with Inflammatory Bowel Diseases: A Hospital-based Survey

    PubMed Central

    Cappello, Maria; Randazzo, Claudia; Bravatà, Ivana; Licata, Anna; Peralta, Sergio; Craxì, Antonio; Almasio, Piero Luigi

    2014-01-01

    BACKGROUND AND AIMS Inflammatory bowel diseases (IBD) are frequently associated with altered liver function tests (LFTs). The causal relationship between abnormal LFTs and IBD is unclear. The aim of our study was to evaluate the prevalence and etiology of LFTs abnormalities and their association with clinical variables in a cohort of IBD patients followed up in a single center. MATERIALS AND METHODS A retrospective review was undertaken of all consecutive IBD in- and outpatients routinely followed up at a single referral center. Clinical and demographic parameters were recorded. Subjects were excluded if they had a previous diagnosis of chronic liver disease. LFT abnormality was defined as an increase in aspartate aminotransferase, (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), or total bilirubin. RESULTS A cohort of 335 patients (179 males, mean age 46.0 ± 15.6 years) was analyzed. Abnormal LFTs were detected in 70 patients (20.9%). In most cases, the alterations were mild and spontaneously returned to normal values in about 60% of patients. Patients with abnormal LFTs were less frequently on treatment with aminosalicylates (22.8 vs. 36.6%, P = 0.04). The most frequent cause for transient abnormal LFTs was drug-induced cholestasis (34.1%), whereas fatty liver was the most frequent cause of persistent liver damage (65.4%). A cholestatic pattern was found in 60.0% of patients and was mainly related to older age, longer duration of disease, and hypertension. CONCLUSIONS The prevalence of LFT abnormalities is relatively high in IBD patients, but the development of severe liver injury is exceptional. Moreover, most alterations of LFTs are mild and spontaneously return to normal values. Drug-induced hepatotoxicity and fatty liver are the most relevant causes of abnormal LFTs in patients with IBD. PMID:24966712

  7. The Trier Social Stress Test protocol for inducing psychological stress.

    PubMed

    Birkett, Melissa A

    2011-10-19

    This article demonstrates a psychological stress protocol for use in a laboratory setting. Protocols that allow researchers to study the biological pathways of the stress response in health and disease are fundamental to the progress of research in stress and anxiety. Although numerous protocols exist for inducing stress response in the laboratory, many neglect to provide a naturalistic context or to incorporate aspects of social and psychological stress. Of psychological stress protocols, meta-analysis suggests that the Trier Social Stress Test (TSST) is the most useful and appropriate standardized protocol for studies of stress hormone reactivity. In the original description of the TSST, researchers sought to design and evaluate a procedure capable of inducing a reliable stress response in the majority of healthy volunteers. These researchers found elevations in heart rate, blood pressure and several endocrine stress markers in response to the TSST (a psychological stressor) compared to a saline injection (a physical stressor). Although the TSST has been modified to meet the needs of various research groups, it generally consists of a waiting period upon arrival, anticipatory speech preparation, speech performance, and verbal arithmetic performance periods, followed by one or more recovery periods. The TSST requires participants to prepare and deliver a speech, and verbally respond to a challenging arithmetic problem in the presence of a socially evaluative audience. Social evaluation and uncontrollability have been identified as key components of stress induction by the TSST. In use for over a decade, the goal of the TSST is to systematically induce a stress response in order to measure differences in reactivity, anxiety and activation of the hypothalamic-pituitary-adrenal (HPA) or sympathetic-adrenal-medullary (SAM) axis during the task. Researchers generally assess changes in self-reported anxiety, physiological measures (e.g. heart rate), and

  8. A case of recurrent earthquake stress cardiomyopathy with a differing wall motion abnormality.

    PubMed

    Bridgman, Paul G; Chan, Christina W; Elliott, John M

    2012-02-01

    We present the case of a Caucasian woman who survived two major earthquakes, presenting on each occasion with stress cardiomyopathy, but with a different pattern of regional wall motion abnormality on the second occasion. The first Christchurch earthquake struck on September 4, 2010. At 7.1 on the Richter scale, it was larger than the major Haiti quake, but miraculously there were no direct fatalities. In the week following, eight women meeting modified Mayo criteria for stress cardiomyopathy presented to Christchurch Hospital. The second Christchurch earthquake was on February 22, 2011. It measured 6.4 on the Richter scale and caused 180 direct fatalities. In the week following this earthquake, 24 women were admitted with stress cardiomyopathy. One patient presented after both earthquakes. This 76-year-old woman first presented on September 4 with 10 hours of chest pain. Electrocardiogram showed inferolateral deep T-wave inversion and QT prolongation. TnI peaked at 0.81 μg/L. Coronary angiography demonstrated diffuse atheroma with a moderate mid LAD lesion that was stented at the time. Echocardiography showed a classic takotsubo pattern. Her follow-up echocardiogram on September 28 was normal and she was completely well at that point. However, during the second earthquake of February 22, she again developed chest pain and shortness of breath. TnI peaked at 1.3 μg/L. Echocardiogram showed a midwall variant takotsubo with apical sparing. She was discharged from hospital on the 25th, planning to leave Christchurch for a new home in another city, but returned for follow-up echocardiogram on July 27. This was normal.

  9. Two-dimensional Doppler echocardiographic correlation of dipyridamole-thallium stress testing with isometric handgrip

    SciTech Connect

    Whitfield, S.; Aurigemma, G.; Pape, L.; Leppo, J. )

    1991-05-01

    To determine how frequently new wall-motion abnormalities that are indicative of ischemia accompany thallium redistribution, 47 consecutive patients underwent two-dimensional, echocardiography during routine dipyridamole-thallium stress testing. A secondary aim of the study was to determine whether the addition of isometric handgrip exercises to the standard dipyridamole imaging protocol increased the frequency of wall-motion abnormalities or thallium redistribution. Echocardiograms and thallium scans were independently interpreted, and wall-motion abnormalities that appeared with dipyridamole, handgrip exercise, or both were compared with results of thallium imaging. Five of 24 patients with thallium redistribution had new wall-motion abnormalities, and the extent (number of segments) of thallium redistribution in these five patients was significantly greater than in those who did not have well-motion abnormalities (p less than 0.03). The addition of isometric handgrip exercises to the imaging protocol did not distinguish between patients with and without new wall-motion abnormalities or thallium redistribution. Thus new wall-motion abnormalities infrequently accompany thallium redistribution in routine dipyridamole stress testing in spite of the addition of handgrip exercises, but when new wall-motion abnormalities are present, they are associated with a greater area of thallium redistribution.

  10. Test and analysis on the abnormal noise of the ultrasonic detection device

    NASA Astrophysics Data System (ADS)

    Li, Guangya; Yang, Mingliang; Wang, Mingquan; Tan, Qiulin; Duan, Nengquan

    2014-03-01

    For the phenomenon that the abnormal noise appear suddenly when the ultrasonic detection device works at the rate of 800mm/min, a vibration testing for this detection device is designed and investigated in this paper. Deep analysis are carried out based on the experimental modal analysis method of point excitation with multiple point three vectors in response and spectrum analysis method. The analysis results demonstrate the main reasons of the abnormal noise, which is due to the resonance between the motor and the ultrasonic station.

  11. Exercise protects against obesity induced semen abnormalities via downregulating stem cell factor, upregulating Ghrelin and normalizing oxidative stress

    PubMed Central

    Alhashem, Fahaid; Alkhateeb, Mahmoud; Sakr, Hussein; Alshahrani, Mesfer; Alsunaidi, Mohammad; Elrefaey, Hesham; Alessa, Riyad; Sarhan, Mohammad; Eleawa, Samy M; Khalil, Mohammad A.

    2014-01-01

    Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12 % of calories as fat); Group II: fed HFD (40 % of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8 % decrease in sperm count, 44.72 % decrease in sperm motility, as well as 47.09 % increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8 % (P=0.0012) and 45.6±4.6 % (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9 %, P=0.0001). Finally, endurance exercise training and Orlistat administration individually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat

  12. Exercise protects against obesity induced semen abnormalities via downregulating stem cell factor, upregulating Ghrelin and normalizing oxidative stress.

    PubMed

    Alhashem, Fahaid; Alkhateeb, Mahmoud; Sakr, Hussein; Alshahrani, Mesfer; Alsunaidi, Mohammad; Elrefaey, Hesham; Alessa, Riyad; Sarhan, Mohammad; Eleawa, Samy M; Khalil, Mohammad A

    2014-01-01

    Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12 % of calories as fat); Group II: fed HFD (40 % of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8 % decrease in sperm count, 44.72 % decrease in sperm motility, as well as 47.09 % increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8 % (P=0.0012) and 45.6±4.6 % (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9 %, P=0.0001). Finally, endurance exercise training and Orlistat administration individually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat

  13. Cognitive emotion regulation fails the stress test.

    PubMed

    Raio, Candace M; Orederu, Temidayo A; Palazzolo, Laura; Shurick, Ashley A; Phelps, Elizabeth A

    2013-09-10

    Cognitive emotion regulation has been widely shown in the laboratory to be an effective way to alter the nature of emotional responses. Despite its success in experimental contexts, however, we often fail to use these strategies in everyday life where stress is pervasive. The successful execution of cognitive regulation relies on intact executive functioning and engagement of the prefrontal cortex, both of which are rapidly impaired by the deleterious effects of stress. Because it is specifically under stressful conditions that we may benefit most from such deliberate forms of emotion regulation, we tested the efficacy of cognitive regulation after stress exposure. Participants first underwent fear-conditioning, where they learned that one stimulus (CS+) predicted an aversive outcome but another predicted a neutral outcome (CS-). Cognitive regulation training directly followed where participants were taught to regulate fear responses to the aversive stimulus. The next day, participants underwent an acute stress induction or a control task before repeating the fear-conditioning task using these newly acquired regulation skills. Skin conductance served as an index of fear arousal, and salivary α-amylase and cortisol concentrations were assayed as neuroendocrine markers of stress response. Although groups showed no differences in fear arousal during initial fear learning, nonstressed participants demonstrated robust fear reduction following regulation training, whereas stressed participants showed no such reduction. Our results suggest that stress markedly impairs the cognitive regulation of emotion and highlights critical limitations of this technique to control affective responses under stress.

  14. Liquid salt environment stress-rupture testing

    DOEpatents

    Ren, Weiju; Holcomb, David E.; Muralidharan, Govindarajan; Wilson, Dane F.

    2016-03-22

    Disclosed herein are systems, devices and methods for stress-rupture testing selected materials within a high-temperature liquid salt environment. Exemplary testing systems include a load train for holding a test specimen within a heated inert gas vessel. A thermal break included in the load train can thermally insulate a load cell positioned along the load train within the inert gas vessel. The test specimen can include a cylindrical gage portion having an internal void filled with a molten salt during stress-rupture testing. The gage portion can have an inner surface area to volume ratio of greater than 20 to maximize the corrosive effect of the molten salt on the specimen material during testing. Also disclosed are methods of making a salt ingot for placement within the test specimen.

  15. Abnormality of the Corpus Callosum in Coalmine Gas Explosion-Related Posttraumatic Stress Disorder

    PubMed Central

    Lang, Xu; Zhuo, Chuanjun; Qin, Wen; Zhang, Quan

    2015-01-01

    Abnormal corpus callosum (CC) has been reported in childhood trauma-related posttraumatic stress disorder (PTSD); however, the nature of white matter (WM) integrity alterations in the CC of young adult-onset PTSD patients is unknown. In this study, 14 victims of a coal mine gas explosion with PTSD and 23 matched coal miners without experiencing the coal mine explosion were enrolled. The differences in fractional anisotropy (FA) within 7 sub-regions of the CC were compared between the two groups. Compared to the controls, PTSD coal miners exhibited significantly reduced FA values in the anterior sub-regions of the CC (P < 0.05, Bonferroni-corrected), which mainly interconnect the bilateral frontal cortices. Our findings indicated that the anterior part of the CC was more severely impaired than the posterior part in young adult-onset PTSD, which suggested the patterns of CC impairment may depend on the developmental stage of the structure when the PTSD occurs. PMID:25799310

  16. Prenatal diagnosis: choices women make about pursuing testing and acting on abnormal results.

    PubMed

    Pryde, P G; Drugan, A; Johnson, M P; Isada, N B; Evans, M I

    1993-09-01

    Liberalization of abortion laws in several US states (e.g., New York and California) coincided with the development of prenatal techniques, which diagnose chromosomal abnormalities and biochemical disorders. Increased use of prenatal diagnostic services has not been accompanied by adequate examination of the decision making process women undergo when contemplating prenatal diagnosis, pregnancy termination, or experimental fetal therapy. The limited literature exploring these issues indicates that many women do not know as much as possible about the health of their fetus. Women who are at risk of abnormal pregnancy tend to become distressed and willing to accept invasive testing, even when they know the significant, albeit low, risks of such testing. Women's perceptions of risk, which stem from complex psychologic-phenomena, are likely to be very inconsistent with objective reality. Neither counseling nor education can easily change these misperceptions. Nevertheless, counseling can at least alter misperceptions enough so they move closer to objective reality. On the other hand, counseling can sway perceptions and choices made based on these perceptions. Decision making is even more complex and emotional when women encounter abnormalities. Considerable social, moral, and psychologic factors influence this process, making this a very problematic area to study. Almost all women who carry an abnormal fetus with a very serious prognosis and a high degree of diagnostic certainty chose to terminate the pregnancy. The decision is much more difficult for women carrying a fetus with less diagnostic or prognostic certainty. Insufficient data exists to determine how they handle these management decisions. Women tend to opt for abortion in cases of chromosomal abnormalities, regardless of the severity or certainty of the outcome. Women carrying a fetus with anatomic disorders with prognostic uncertainty or less severity choose to abort at lower rates. More research is needed to

  17. Prevalence and Determinants of True Thyroid Dysfunction Among Pediatric Referrals for Abnormal Thyroid Function Tests

    PubMed Central

    Lahoti, Amit; Klein, Jason; Schumaker, Tiffany; Vuguin, Patricia; Frank, Graeme

    2016-01-01

    Background/Aims. Abnormalities in thyroid function tests (TFTs) are a common referral reason for pediatric endocrine evaluation. However, a sizable proportion of these laboratory abnormalities do not warrant therapy or endocrine follow-up. The objectives of this study were (a) to evaluate the prevalence of true thyroid dysfunction among pediatric endocrinology referrals for abnormal TFTs; (b) to identify the historical, clinical, and laboratory characteristics that predict decision to treat. Methods. This was a retrospective chart review of patients evaluated in pediatric endocrinology office during a weekly clinic designated for new referrals for abnormal TFTs in 2010. Results. A total of 230 patients were included in the study. Median age at referral was 12 years (range = 2-18); 56% were females. Routine screening was cited as the reason for performing TFTs by 33% patients. Majority was evaluated for hypothyroidism (n = 206). Elevated thyroid-stimulating hormone was the most common referral reason (n = 140). A total of 41 out of 206 patients were treated for hypothyroidism. Conclusions. Prevalence of hypothyroidism was 20%. Thyroid follow-up was not recommended for nearly one third of the patients. Among all the factors analyzed, an elevated thyroid-stimulating hormone level and antithyroglobulin antibodies strongly correlated with the decision to treat (P < .005). PMID:27336020

  18. Prevalence and Determinants of True Thyroid Dysfunction Among Pediatric Referrals for Abnormal Thyroid Function Tests.

    PubMed

    Lahoti, Amit; Klein, Jason; Schumaker, Tiffany; Vuguin, Patricia; Frank, Graeme

    2016-01-01

    Background/Aims. Abnormalities in thyroid function tests (TFTs) are a common referral reason for pediatric endocrine evaluation. However, a sizable proportion of these laboratory abnormalities do not warrant therapy or endocrine follow-up. The objectives of this study were (a) to evaluate the prevalence of true thyroid dysfunction among pediatric endocrinology referrals for abnormal TFTs; (b) to identify the historical, clinical, and laboratory characteristics that predict decision to treat. Methods. This was a retrospective chart review of patients evaluated in pediatric endocrinology office during a weekly clinic designated for new referrals for abnormal TFTs in 2010. Results. A total of 230 patients were included in the study. Median age at referral was 12 years (range = 2-18); 56% were females. Routine screening was cited as the reason for performing TFTs by 33% patients. Majority was evaluated for hypothyroidism (n = 206). Elevated thyroid-stimulating hormone was the most common referral reason (n = 140). A total of 41 out of 206 patients were treated for hypothyroidism. Conclusions. Prevalence of hypothyroidism was 20%. Thyroid follow-up was not recommended for nearly one third of the patients. Among all the factors analyzed, an elevated thyroid-stimulating hormone level and antithyroglobulin antibodies strongly correlated with the decision to treat (P < .005).

  19. Prognostic impact of coronary microcirculation abnormalities in systemic sclerosis: a prospective study to evaluate the role of non-invasive tests

    PubMed Central

    2013-01-01

    Introduction Microcirculation dysfunction is a typical feature of systemic sclerosis (SSc) and represents the earliest abnormality of primary myocardial involvement. We assessed coronary microcirculation status by combining two functional tests in SSc patients and estimating its impact on disease outcome. Methods Forty-one SSc patients, asymptomatic for coronary artery disease, were tested for coronary flow velocity reserve (CFR) by transthoracic-echo-Doppler with adenosine infusion (A-TTE) and for left ventricular wall motion abnormalities (WMA) by dobutamine stress echocardiography (DSE). Myocardial multi-detector computed tomography (MDCT) enabled the presence of epicardial stenosis, which could interfere with the accuracy of the tests, to be excluded. Patient survival rate was assessed over a 6.7- ± 3.5-year follow-up. Results Nineteen out of 41 (46%) SSc patients had a reduced CFR (≤2.5) and in 16/41 (39%) a WMA was observed during DSE. Furthermore, 13/41 (32%) patients showed pathological CFR and WMA. An inverse correlation between wall motion score index (WMSI) during DSE and CFR value (r = -0.57, P <0.0001) was observed; in addition, CFR was significantly reduced (2.21 ± 0.38) in patients with WMA as compared to those without (2.94 ± 0.60) (P <0.0001). In 12 patients with abnormal DSE, MDCT was used to exclude macrovasculopathy. During a 6.7- ± 3.5-year follow-up seven patients with abnormal coronary functional tests died of disease-related causes, compared to only one patient with normal tests. Conclusions A-TTE and DSE tests are useful tools to detect non-invasively pre-clinical microcirculation abnormalities in SSc patients; moreover, abnormal CFR and WMA might be related to a worse disease outcome suggesting a prognostic value of these tests, similar to other myocardial diseases. PMID:23302110

  20. Automatic recognition of abnormal cells in cytological tests using multispectral imaging

    NASA Astrophysics Data System (ADS)

    Gertych, A.; Galliano, G.; Bose, S.; Farkas, D. L.

    2010-03-01

    Cervical cancer is the leading cause of gynecologic disease-related death worldwide, but is almost completely preventable with regular screening, for which cytological testing is a method of choice. Although such testing has radically lowered the death rate from cervical cancer, it is plagued by low sensitivity and inter-observer variability. Moreover, its effectiveness is still restricted because the recognition of shape and morphology of nuclei is compromised by overlapping and clumped cells. Multispectral imaging can aid enhanced morphological characterization of cytological specimens. Features including spectral intensity and texture, reflecting relevant morphological differences between normal and abnormal cells, can be derived from cytopathology images and utilized in a detection/classification scheme. Our automated processing of multispectral image cubes yields nuclear objects which are subjected to classification facilitated by a library of spectral signatures obtained from normal and abnormal cells, as marked by experts. Clumps are processed separately with reduced set of signatures. Implementation of this method yields high rate of successful detection and classification of nuclei into predefined malignant and premalignant types and correlates well with those obtained by an expert. Our multispectral approach may have an impact on the diagnostic workflow of cytological tests. Abnormal cells can be automatically highlighted and quantified, thus objectivity and performance of the reading can be improved in a way which is currently unavailable in clinical setting.

  1. The Status of Spectral EEG Abnormality as a Diagnostic Test for Schizophrenia

    PubMed Central

    Boutros, Nash N.; Arfken, Cynthia; Galderisi, Silvana; Warrick, Joshua; Pratt, Garrett; Iacono, William

    2008-01-01

    Objective A literature review was conducted to ascertain whether or not EEG spectral abnormalities are consistent enough to warrant additional effort towards developing them into a clinical diagnostic test for schizophrenia. Methods Fifty three papers met criteria for inclusion into the review and 15 were included in a meta-analysis of the degree of significance of EEG deviations as compared to healthy controls. Studies were classified based on a 4-step approach based on guidelines for evaluating the clinical usefulness of a diagnostic test. Results Our review and meta-analysis revealed that most of the abnormalities are replicated in the expected directions with the most consistent results related to the increased preponderance of slow rhythms in schizophrenia patients. This effect remained consistent in un-medicated patients. Only a small number of studies provided data on the sensitivity and specificity of the findings in differentiating among the psychiatric disorders that frequently appear on the same differential diagnostic list as schizophrenia (step 3 studies). No multicenter studies using standardized assessment criteria were found (step 4 studies). Conclusions Additional Step 3 and Step 4 studies are needed to draw conclusions on the usefulness of EEG spectral abnormalities as a diagnostic test for schizophrenia PMID:18160260

  2. Bilateral Sensory Abnormalities in Patients with Unilateral Neuropathic Pain; A Quantitative Sensory Testing (QST) Study

    PubMed Central

    Konopka, Karl-Heinz; Harbers, Marten; Houghton, Andrea; Kortekaas, Rudie; van Vliet, Andre; Timmerman, Wia; den Boer, Johan A.; Struys, Michel M.R.F.; van Wijhe, Marten

    2012-01-01

    In patients who experience unilateral chronic pain, abnormal sensory perception at the non-painful side has been reported. Contralateral sensory changes in these patients have been given little attention, possibly because they are regarded as clinically irrelevant. Still, bilateral sensory changes in these patients could become clinically relevant if they challenge the correct identification of their sensory dysfunction in terms of hyperalgesia and allodynia. Therefore, we have used the standardized quantitative sensory testing (QST) protocol of the German Research Network on Neuropathic Pain (DFNS) to investigate somatosensory function at the painful side and the corresponding non-painful side in unilateral neuropathic pain patients using gender- and age-matched healthy volunteers as a reference cohort. Sensory abnormalities were observed across all QST parameters at the painful side, but also, to a lesser extent, at the contralateral, non-painful side. Similar relative distributions regarding sensory loss/gain for non-nociceptive and nociceptive stimuli were found for both sides. Once a sensory abnormality for a QST parameter at the affected side was observed, the prevalence of an abnormality for the same parameter at the non-affected side was as high as 57% (for Pressure Pain Threshold). Our results show that bilateral sensory dysfunction in patients with unilateral neuropathic pain is more rule than exception. Therefore, this phenomenon should be taken into account for appropriate diagnostic evaluation in clinical practice. This is particularly true for mechanical stimuli where the 95% Confidence Interval for the prevalence of sensory abnormalities at the non-painful side ranges between 33% and 50%. PMID:22629414

  3. Computer-enhanced thallium scintigrams in asymptomatic men with abnormal exercise tests

    SciTech Connect

    Uhl, G.S.; Kay, T.N.; Hickman, J.R., Jr.

    1981-12-01

    The usefulness of computer-enhanced thallium-201 myocardial perfusion scintigraphy in excluding the diagnosis of coronary artery disease in asymptomatic patients showing abnormal exercise electrocardiograms is evaluated. Multigated thallium scans were obtained immediately following and 3 or 4 hours after maximal exercise testing in 191 consecutive asymptomatic Air Force aircrew members who had shown abnormal exercise electrocardiograms and who were due to undergo coronary angiography. Computer enhancement of the raw images is found to lead to four false positive and two false negative scintigrams as revealed by angiographic results, while the group of 15 with subcritical coronary disease exhibited equivocal results. Results reveal that enhanced thallium scintigrams are an accurate diagnostics tool in detecting myocardial ischemia in asymptomatic patients and may be used in counseling asymptomatic patients on their likelihood of having coronary artery disease.

  4. Limited Clinical Utility of Non-invasive Prenatal Testing for Subchromosomal Abnormalities.

    PubMed

    Lo, Kitty K; Karampetsou, Evangelia; Boustred, Christopher; McKay, Fiona; Mason, Sarah; Hill, Melissa; Plagnol, Vincent; Chitty, Lyn S

    2016-01-01

    The use of massively parallel sequencing of maternal cfDNA for non-invasive prenatal testing (NIPT) of aneuploidy is widely available. Recently, the scope of testing has increased to include selected subchromosomal abnormalities, but the number of samples reported has been small. We developed a calling pipeline based on a segmentation algorithm for the detection of these rearrangements in maternal plasma. The same read depth used in our standard pipeline for aneuploidy NIPT detected 15/18 (83%) samples with pathogenic rearrangements > 6 Mb but only 2/10 samples with rearrangements < 6 Mb, unless they were maternally inherited. There were two false-positive calls in 534 samples with no known subchromosomal abnormalities (specificity 99.6%). Using higher read depths, we detected 29/31 fetal subchromosomal abnormalities, including the three samples with maternally inherited microduplications. We conclude that test sensitivity is a function of the fetal fraction, read depth, and size of the fetal CNV and that at least one of the two false negatives is due to a low fetal fraction. The lack of an independent method for determining fetal fraction, especially for female fetuses, leads to uncertainty in test sensitivity, which currently has implications for this technique's future as a clinical diagnostic test. Furthermore, to be effective, NIPT must be able to detect chromosomal rearrangements across the whole genome for a very low false-positive rate. Because standard NIPT can only detect the majority of larger (>6 Mb) chromosomal rearrangements and requires knowledge of fetal fraction, we consider that it is not yet ready for routine clinical implementation. PMID:26708752

  5. Progranulin haploinsufficiency causes biphasic social dominance abnormalities in the tube test.

    PubMed

    Arrant, A E; Filiano, A J; Warmus, B A; Hall, A M; Roberson, E D

    2016-07-01

    Loss-of-function mutations in progranulin (GRN) are a major autosomal dominant cause of frontotemporal dementia (FTD), a neurodegenerative disorder in which social behavior is disrupted. Progranulin-insufficient mice, both Grn(+/-) and Grn(-/-) , are used as models of FTD due to GRN mutations, with Grn(+/-) mice mimicking the progranulin haploinsufficiency of FTD patients with GRN mutations. Grn(+/-) mice have increased social dominance in the tube test at 6 months of age, although this phenotype has not been reported in Grn(-/-) mice. In this study, we investigated how the tube test phenotype of progranulin-insufficient mice changes with age, determined its robustness under several testing conditions, and explored the associated cellular mechanisms. We observed biphasic social dominance abnormalities in Grn(+/-) mice: at 6-8 months, Grn(+/-) mice were more dominant than wild-type littermates, while after 9 months of age, Grn(+/-) mice were less dominant. In contrast, Grn(-/-) mice did not exhibit abnormal social dominance, suggesting that progranulin haploinsufficiency has distinct effects from complete progranulin deficiency. The biphasic tube test phenotype of Grn(+/-) mice was associated with abnormal cellular signaling and neuronal morphology in the amygdala and prefrontal cortex. At 6-9 months, Grn(+/-) mice exhibited increased mTORC2/Akt signaling in the amygdala and enhanced dendritic arbors in the basomedial amygdala, and at 9-16 months Grn(+/-) mice exhibited diminished basal dendritic arbors in the prelimbic cortex. These data show a progressive change in tube test dominance in Grn(+/-) mice and highlight potential underlying mechanisms by which progranulin insufficiency may disrupt social behavior. PMID:27213486

  6. Progranulin haploinsufficiency causes biphasic social dominance abnormalities in the tube test.

    PubMed

    Arrant, A E; Filiano, A J; Warmus, B A; Hall, A M; Roberson, E D

    2016-07-01

    Loss-of-function mutations in progranulin (GRN) are a major autosomal dominant cause of frontotemporal dementia (FTD), a neurodegenerative disorder in which social behavior is disrupted. Progranulin-insufficient mice, both Grn(+/-) and Grn(-/-) , are used as models of FTD due to GRN mutations, with Grn(+/-) mice mimicking the progranulin haploinsufficiency of FTD patients with GRN mutations. Grn(+/-) mice have increased social dominance in the tube test at 6 months of age, although this phenotype has not been reported in Grn(-/-) mice. In this study, we investigated how the tube test phenotype of progranulin-insufficient mice changes with age, determined its robustness under several testing conditions, and explored the associated cellular mechanisms. We observed biphasic social dominance abnormalities in Grn(+/-) mice: at 6-8 months, Grn(+/-) mice were more dominant than wild-type littermates, while after 9 months of age, Grn(+/-) mice were less dominant. In contrast, Grn(-/-) mice did not exhibit abnormal social dominance, suggesting that progranulin haploinsufficiency has distinct effects from complete progranulin deficiency. The biphasic tube test phenotype of Grn(+/-) mice was associated with abnormal cellular signaling and neuronal morphology in the amygdala and prefrontal cortex. At 6-9 months, Grn(+/-) mice exhibited increased mTORC2/Akt signaling in the amygdala and enhanced dendritic arbors in the basomedial amygdala, and at 9-16 months Grn(+/-) mice exhibited diminished basal dendritic arbors in the prelimbic cortex. These data show a progressive change in tube test dominance in Grn(+/-) mice and highlight potential underlying mechanisms by which progranulin insufficiency may disrupt social behavior.

  7. Limited Clinical Utility of Non-invasive Prenatal Testing for Subchromosomal Abnormalities

    PubMed Central

    Lo, Kitty K.; Karampetsou, Evangelia; Boustred, Christopher; McKay, Fiona; Mason, Sarah; Hill, Melissa; Plagnol, Vincent; Chitty, Lyn S.

    2016-01-01

    The use of massively parallel sequencing of maternal cfDNA for non-invasive prenatal testing (NIPT) of aneuploidy is widely available. Recently, the scope of testing has increased to include selected subchromosomal abnormalities, but the number of samples reported has been small. We developed a calling pipeline based on a segmentation algorithm for the detection of these rearrangements in maternal plasma. The same read depth used in our standard pipeline for aneuploidy NIPT detected 15/18 (83%) samples with pathogenic rearrangements > 6 Mb but only 2/10 samples with rearrangements < 6 Mb, unless they were maternally inherited. There were two false-positive calls in 534 samples with no known subchromosomal abnormalities (specificity 99.6%). Using higher read depths, we detected 29/31 fetal subchromosomal abnormalities, including the three samples with maternally inherited microduplications. We conclude that test sensitivity is a function of the fetal fraction, read depth, and size of the fetal CNV and that at least one of the two false negatives is due to a low fetal fraction. The lack of an independent method for determining fetal fraction, especially for female fetuses, leads to uncertainty in test sensitivity, which currently has implications for this technique’s future as a clinical diagnostic test. Furthermore, to be effective, NIPT must be able to detect chromosomal rearrangements across the whole genome for a very low false-positive rate. Because standard NIPT can only detect the majority of larger (>6 Mb) chromosomal rearrangements and requires knowledge of fetal fraction, we consider that it is not yet ready for routine clinical implementation. PMID:26708752

  8. 12 CFR 325.204 - Annual stress tests required.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Annual stress tests required. 325.204 Section... POLICY CAPITAL MAINTENANCE Annual Stress Test § 325.204 Annual stress tests required. (a) General... conduct a stress test on or before March 31 of each calendar year based on financial data as of...

  9. 12 CFR 46.5 - Annual stress test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Annual stress test. 46.5 Section 46.5 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY ANNUAL STRESS TEST § 46.5 Annual stress test. Each covered institution must conduct the annual stress test under this part subject to...

  10. 12 CFR 325.207 - Publication of stress test results.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Publication of stress test results. 325.207... GENERAL POLICY CAPITAL MAINTENANCE Annual Stress Test § 325.207 Publication of stress test results. (a... annual stress test in the period starting June 15 and ending June 30. (2) An over $50 billion...

  11. 12 CFR 46.5 - Annual stress test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Annual stress test. 46.5 Section 46.5 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY ANNUAL STRESS TEST § 46.5 Annual stress test. Each covered institution must conduct the annual stress test under this part subject to...

  12. 12 CFR 325.204 - Annual stress tests required.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Annual stress tests required. 325.204 Section... POLICY CAPITAL MAINTENANCE Annual Stress Test § 325.204 Annual stress tests required. (a) General... conduct a stress test on or before March 31 of each calendar year based on financial data as of...

  13. 12 CFR 252.145 - Mid-cycle stress test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Mid-cycle stress test. 252.145 Section 252.145... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered Companies § 252.145 Mid-cycle stress test. (a) Mid-cycle stress test requirement. In addition to the...

  14. 12 CFR 325.207 - Publication of stress test results.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Publication of stress test results. 325.207... GENERAL POLICY CAPITAL MAINTENANCE Annual Stress Test § 325.207 Publication of stress test results. (a... annual stress test in the period starting June 15 and ending June 30. (2) An over $50 billion...

  15. 12 CFR 252.145 - Mid-cycle stress test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Mid-cycle stress test. 252.145 Section 252.145... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered Companies § 252.145 Mid-cycle stress test. (a) Mid-cycle stress test requirement. In addition to the...

  16. [Is the abnormal toxicity test still relevant for the safety of vaccines, sera and immunoglobulins?

    PubMed

    Krämer, Beate; Nagel, Margit; Duchow, Karin; Schwanig, Michael; Cussler, Klaus

    1996-01-01

    The German Pharmacopoeia (DAB) requires the abnormal toxicity test (ATT) using mice and guinea pigs as a non-specific safety test for vaccines, sera and immuno-globulines. The purpose of this project was to investigate the relevance of ATT after the introduction of GMP- and GLP-principles in the manufacturing of biological products. A great variability in the test performance became evident for the different test laboratories, involving the animal number as well as the vaccine dosage administration and test duration. The retrospective analysis of ATT results reveals reasons for the incompatibility of particular preparation groups, vaccine components or additives with the animal species used. There were highly significant differences between the manufacturers and the PEI regarding the frequency of deviating test results for identical test batches. Positive ATT"s never resulted from the insufficient quality of a batch. On the other hand vaccines causing adverse reactions in the target species were not identified by the ATT. For these reasons the abnormal toxicity test is unsuitable to detect harmful batches. The results of the analysis of data show that finally the ATT has always been passed, i.e. there was no retention by the vaccine manufacturers and no refusal by the controlling authorities due to the ATT-results. Considering the present animal model and the questionable transferability of the test results to the target species only a poor reliability is evident. Taking into account aspects of drug safety and animal welfare it is recommended to the DAB to omit the ATT.

  17. [Tilt test and orthostatic intolerance: abnormalities in the neural sympathetic response to gravitational stimulus].

    PubMed

    Furlan, R

    2001-05-01

    In the present manuscript the different methodologies aimed at assessing the autonomic profile in humans during a gravitational stimulus have been described. In addition, strengths and drawbacks of the tilt test in relation to occasional orthostatic intolerance were addressed. Finally, different autonomic abnormalities underlying occasional and chronic orthostatic intolerance syndromes have been schematically highlighted. The direct recording of the neural sympathetic discharge from the peroneal nerve (MSNA), in spite of its invasive nature, still represents the recognized reference to quantify the changes in the sympathetic activity to the vessels attending postural modifications. The increase of plasma norepinephrine during a tilt test is achieved by both an increase in plasma spillover and a concomitant decrease in systemic clearance. Changes in the indices of cardiac sympathetic and vagal modulation may also be quantified during a tilt test by power spectrum analysis of RR interval variability. The spectral markers of cardiac autonomic control, if evaluated concomitantly with MSNA, may contribute to assess abnormalities in the regional distribution of the sympathetic activity to the heart and the vessels. The capability of the tilt test of reproducing a vasovagal event or of inducing "false positive responses" seems to be markedly affected by the age, thus suggesting that additional or different etiopathogenetic mechanisms might be involved in the loss of consciousness in older as compared to younger subjects. In subjects suffering from occasional or habitual neurally mediated syncope an increase or, respectively, a decrease in cardiac and vascular sympathetic modulation has been documented before the loss of consciousness. In patients with pure autonomic failure, a global dysautonomia affecting both the sympathetic and the vagal modulation to the heart, seems to be present. In chronic orthostatic intolerance, the most common form of dysautonomia of young women

  18. Notification of abnormal lab test results in an electronic medical record: do any safety concerns remain?

    PubMed Central

    Singh, Hardeep; Thomas, Eric J.; Sittig, Dean F.; Wilson, Lindsey; Espadas, Donna; Khan, Myrna M.; Petersen, Laura A.

    2010-01-01

    Background: Follow-up of abnormal outpatient laboratory test results is a major patient safety concern. Electronic medical records can potentially address this concern through automated notification. We examined whether automated notifications of abnormal laboratory results (alerts) in an integrated electronic medical record resulted in timely follow-up actions. Methods: We studied four alerts: hemoglobin A1c (HbA1c) ≥15%, positive hepatitis C antibody (HCV), prostate specific antigen (PSA) ≥15 ng/mL, and thyroid stimulating hormone (TSH) ≥ 15 mIU/L. An alert tracking system determined whether the alert was acknowledged (i.e. provider clicked on and opened the message) within two weeks of transmission; acknowledged alerts were considered read. Within 30 days of result transmission, record review and provider contact determined follow-up actions (e.g. patient contact, treatment etc.). Multivariable logistic regression models analyzed predictors for lack of timely follow-up. Results: Between May 2008 and December 2008, 78,158 tests (HbA1c, HCV, TSH and PSA) were performed, of which 1163 (1.48%) were transmitted as alerts; 10.2% of these (119/1163) were unacknowledged. Timely follow-up was lacking in 79 (6.8%) and was statistically not different for acknowledged and unacknowledged alerts (6.4% vs. 10.1%; p =.13). Two-hundred two alerts (17.4% of 1163) arose from unnecessarily ordered (redundant) tests. Alerts for a new versus known diagnosis were more likely to lack timely follow-up (OR: 7.35; 95% CI: 4.16-12.97) whereas alerts related to redundant tests were less likely to lack timely follow-up (OR: 0.24; 95% CI: 0.07-0.84). Conclusions: Safety concerns related to timely patient follow-up remain despite automated notification of non-life threatening abnormal laboratory results in the outpatient setting. PMID:20193832

  19. Upper extremity stress fractures and spondylolysis in an adolescent baseball pitcher with an associated endocrine abnormality: a case report.

    PubMed

    Li, Xinning; Heffernan, Michael J; Mortimer, Errol S

    2010-06-01

    Lower extremity stress fractures are relatively common among competitive athletes. Stress fractures of the upper extremity, however, are rare and most have been reported in the literature as case reports. We present a case of an adolescent baseball pitcher who had both proximal humeral and ulnar shaft stress fractures, as well as spondylolysis of the lumbar spine. This particular patient also had an underlying endocrine abnormality of secondary hyperparathyroidism with a deficiency in vitamin D. A bone mineral density panel demonstrated a high T score (+2.79 SD above the mean) and the patient's biologic bone age was noted to be 2 years ahead of his chronologic age. The patient was treated with a course of vitamin D and calcium supplementation. After treatment, both the vitamin D and parathyroid hormone returned to normal levels. The upper extremity stress fractures and spondylolysis were managed conservatively and he was able to return to full activity and baseball. For patients who present with multiple stress fractures not associated with consistent high levels of repeated stress, a bone mineral density panel should be considered. If vitamin D deficiency is present, a course of oral supplementation may be considered in the management. An endocrinology consult should also be considered in patients who present with multiple stress fractures. Conservative management of upper extremity stress fractures and spondylolysis was successful in returning this patient back to his previous activity level. PMID:20502233

  20. Upper extremity stress fractures and spondylolysis in an adolescent baseball pitcher with an associated endocrine abnormality: a case report.

    PubMed

    Li, Xinning; Heffernan, Michael J; Mortimer, Errol S

    2010-06-01

    Lower extremity stress fractures are relatively common among competitive athletes. Stress fractures of the upper extremity, however, are rare and most have been reported in the literature as case reports. We present a case of an adolescent baseball pitcher who had both proximal humeral and ulnar shaft stress fractures, as well as spondylolysis of the lumbar spine. This particular patient also had an underlying endocrine abnormality of secondary hyperparathyroidism with a deficiency in vitamin D. A bone mineral density panel demonstrated a high T score (+2.79 SD above the mean) and the patient's biologic bone age was noted to be 2 years ahead of his chronologic age. The patient was treated with a course of vitamin D and calcium supplementation. After treatment, both the vitamin D and parathyroid hormone returned to normal levels. The upper extremity stress fractures and spondylolysis were managed conservatively and he was able to return to full activity and baseball. For patients who present with multiple stress fractures not associated with consistent high levels of repeated stress, a bone mineral density panel should be considered. If vitamin D deficiency is present, a course of oral supplementation may be considered in the management. An endocrinology consult should also be considered in patients who present with multiple stress fractures. Conservative management of upper extremity stress fractures and spondylolysis was successful in returning this patient back to his previous activity level.

  1. Predictive value of specific ultrasound findings when used as a screening test for abnormalities on VCUG

    PubMed Central

    Logvinenko, Tanya; Chow, Jeanne S.; Nelson, Caleb P.

    2015-01-01

    Summary Background Renal and bladder ultrasound (RBUS) is often used as an initial screening test for children after urinary tract infection (UTI). The 2011 AAP guidelines specifically recommend that RBUS be performed first, with voiding cystourethrogram (VCUG) to be performed only if the ultrasound is abnormal. While prior research has suggested that RBUS is neither sensitive nor specific for VCUG findings, such as vesicoureteral reflux (VUR), it is uncertain as to whether specific RBUS findings, alone or in combination, might make RBUS more useful as a predictor of VCUG abnormalities. Aims To evaluate the association of specific RBUS with VCUG findings, and determine whether predictive models that accurately predict patients at high risk of VCUG abnormalities, based on RBUS findings, can be constructed. Methods and study sample A total of 3995 patients were identified with VCUG and RBUS performed on the same day. The RBUS and VCUG reports were reviewed and the findings were classified. Analysis was limited to patients aged 0–60 months with no prior postnatal genitourinary imaging and no history of prenatal hydronephrosis. Analysis The associations between large numbers of specific RBUS findings with abnormalities seen on VCUG were investigated. Both multivariate logistic models and a neural network machine learning algorithms were constructed to evaluate the predictive power of RBUS for VCUG abnormalities (including VUR or bladder/urethral findings). Sensitivity, specificity, predictive values and area under receiving operating curves (AUROC) of RBUS for VCUG abnormalities were determined. Results A total of 2259 patients with UTI as the indication for imaging were identified. The RBUS was reported as “normal” in 75.0%. On VCUG, any VUR was identified in 41.7%, VUR grade >II in 20.9%, and VUR grade >III in 2.8%. Many individual RBUS findings were significantly associated with VUR on VCUG. Despite these strong univariate associations, multivariate modeling

  2. Abnormal structure of fear circuitry in pediatric post-traumatic stress disorder.

    PubMed

    Keding, Taylor J; Herringa, Ryan J

    2015-02-01

    Structural brain studies of adult post-traumatic stress disorder (PTSD) show reduced gray matter volume (GMV) in fear regulatory areas including the ventromedial prefrontal cortex (vmPFC) and hippocampus. Surprisingly, neither finding has been reported in pediatric PTSD. One possibility is that they represent age-dependent effects that are not fully apparent until adulthood. In addition, lower-resolution MRI and image processing in prior studies may have limited detection of such differences. Here we examine fear circuitry GMV, including age-related differences, using higher-resolution MRI in pediatric PTSD vs healthy youth. In a cross-sectional design, 3 T anatomical brain MRI was acquired in 27 medication-free youth with PTSD and 27 healthy non-traumatized youth of comparable age, sex, and IQ. Voxel-based morphometry was used to compare GMV in a priori regions including the medial prefrontal cortex and amygdala/hippocampus. Compared with healthy youth, PTSD youth had reduced GMV but no age-related differences in anterior vmPFC (BA 10/11, Z=4.5), which inversely correlated with PTSD duration. In contrast, although there was no overall group difference in hippocampal volume, a group × age interaction (Z=3.6) was present in the right anterior hippocampus. Here, age positively predicted hippocampal volume in healthy youth but negatively predicted volume in PTSD youth. Within the PTSD group, re-experiencing symptoms inversely correlated with subgenual anterior cingulate cortex (sgACC, Z=3.7) and right anterior hippocampus (Z=3.5) GMV. Pediatric PTSD is associated with abnormal structure of the vmPFC and age-related differences in the hippocampus, regions important in the extinction and contextual gating of fear. Reduced anterior vmPFC volume may confer impaired recovery from illness, consistent with its role in the allocation of attentional resources. In contrast, individual differences in sgACC volume were associated with re-experiencing symptoms, consistent with

  3. 12 CFR 252.144 - Annual stress test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Annual stress test. 252.144 Section 252.144... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered Companies § 252.144 Annual stress test. (a) In general. A covered company must conduct an annual stress...

  4. 12 CFR 615.5141 - Stress tests for mortgage securities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 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...

  5. 12 CFR 252.144 - Annual stress test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Annual stress test. 252.144 Section 252.144... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered Companies § 252.144 Annual stress test. (a) In general. A covered company must conduct an annual stress...

  6. 12 CFR 615.5141 - Stress tests for mortgage securities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 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...

  7. 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...

  8. 12 CFR 615.5141 - Stress tests for mortgage securities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 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...

  9. Resveratrol Treatment after Status Epilepticus Restrains Neurodegeneration and Abnormal Neurogenesis with Suppression of Oxidative Stress and Inflammation.

    PubMed

    Mishra, Vikas; Shuai, Bing; Kodali, Maheedhar; Shetty, Geetha A; Hattiangady, Bharathi; Rao, Xiaolan; Shetty, Ashok K

    2015-12-07

    Antiepileptic drug therapy, though beneficial for restraining seizures, cannot thwart status epilepticus (SE) induced neurodegeneration or down-stream detrimental changes. We investigated the efficacy of resveratrol (RESV) for preventing SE-induced neurodegeneration, abnormal neurogenesis, oxidative stress and inflammation in the hippocampus. We induced SE in young rats and treated with either vehicle or RESV, commencing an hour after SE induction and continuing every hour for three-hours on SE day and twice daily thereafter for 3 days. Seizures were terminated in both groups two-hours after SE with a diazepam injection. In contrast to the vehicle-treated group, the hippocampus of animals receiving RESV during and after SE presented no loss of glutamatergic neurons in hippocampal cell layers, diminished loss of inhibitory interneurons expressing parvalbumin, somatostatin and neuropeptide Y in the dentate gyrus, reduced aberrant neurogenesis with preservation of reelin + interneurons, lowered concentration of oxidative stress byproduct malondialdehyde and pro-inflammatory cytokine tumor necrosis factor-alpha, normalized expression of oxidative stress responsive genes and diminished numbers of activated microglia. Thus, 4 days of RESV treatment after SE is efficacious for thwarting glutamatergic neuron degeneration, alleviating interneuron loss and abnormal neurogenesis, and suppressing oxidative stress and inflammation. These results have implications for restraining SE-induced chronic temporal lobe epilepsy.

  10. Historical data analyses and scientific knowledge suggest complete removal of the abnormal toxicity test as a quality control test.

    PubMed

    Garbe, Joerg H O; Ausborn, Susanne; Beggs, Claire; Bopst, Martin; Joos, Angelika; Kitashova, Alexandra A; Kovbasenco, Olga; Schiller, Claus-Dieter; Schwinger, Martina; Semenova, Natalia; Smirnova, Lilia; Stodart, Fraser; Visalli, Thomas; Vromans, Lisette

    2014-11-01

    In the early 1900s, the abnormal toxicity test (ATT) was developed as an auxiliary means to ensure safe and consistent antiserum production. Today, the ATT is utilized as a quality control (QC) release test according to pharmacopoeial or other regulatory requirements. The study design has not been changed since around 1940. The evidence of abnormal toxicity testing as a prediction for harmful batches is highly questionable and lacks a scientific rationale. Numerous reviews of historical ATT results have revealed that no reliable conclusions can be drawn from this QC measure. Modern pharmaceutical manufacturers have thorough control of the manufacturing process and comply with good manufacturing practice rules. Contaminants are appropriately controlled by complying with the validated manufacturing processes and strict QC batch release confirming batch-to-batch consistency. Recognizing that product safety, efficacy, and stability can be ensured with strict QC measures, nowadays most regulatory authorities do not require the ATT for most product classes. In line with the replacement, reduction, and refinement (3Rs) initiative, the test requirement has been deleted from approximately 80 monographs of the European Pharmacopoeia and for the majority of product classes in the United States. For these reasons, it is recommended that the ATT should be consistently omitted world-wide and be removed from pharmacopoeias and other regulatory requirements.

  11. Amelogenin test abnormalities revealed in Belarusian population during forensic DNA analysis.

    PubMed

    Borovko, Sergey; Shyla, Alena; Korban, Victorya; Borovko, Alexandra

    2015-03-01

    Study of gender markers is a part of routine forensic genetic examination of crime scene and reference samples, paternity testing and personal identification. Amelogenin locus as a gender marker is included in majority of forensic STR kits of different manufacturers. In current study we report 11 cases of amelogenin abnormalities identified in males of Belarusian origin: 9 cases of AMELY dropout and 2 cases of AMELX dropout. Cases were obtained from forensic casework (n=9) and paternity testing (n=2) groups. In 4 out of 9 AMELY-negative cases deletion of AMELY was associated with the loss of DYS458 marker. In addition, we identified 3 males with SRY-positive XX male syndrome. Deletion of the long arm of the Y-chromosome was detected in two XX males. Loss of the major part of the Y-chromosome was identified in the third XX male. The presence of two X-chromosomes in XX males was confirmed with the use of Mentype(®) Argus X-8 PCR Amplification Kit. AMELY null allele observed in 2 out of 9 cases with AMELY dropout can be caused by mutation in the primer-binding site of AMELY allele. Primer-binding site mutations of AMELX can result in AMELX dropout identified in 2 cases with amplification failure of AMELX. Our study represents the first report and molecular genetic investigation of amelogenin abnormalities in the Belarusian population.

  12. Neighborhood factors associated with time to resolution following an abnormal breast or cervical cancer screening test

    PubMed Central

    Plascak, Jesse J.; Llanos, Adana A.; Pennell, Michael L.; Weier, Rory C.; Paskett, Electra D.

    2014-01-01

    Background The effect of neighborhood and healthcare access factors on cancer outcomes among patients enrolled in navigator programs is not clearly understood. This study assessed associations between: 1) neighborhood factors and diagnostic time to resolution (TTR) and, 2) geographic access and TTR following an abnormal breast or cervical cancer screening test among women participating in the Ohio Patient Navigator Research Program (OPNRP). Methods Patient (demographic, socioeconomic status [SES], home-to-clinic distance) and neighborhood (deprivation, racial segregation) characteristics of 801 women living in one of 285 census tracts (CTs) in greater Columbus, Ohio were examined. Randomization to receive navigation occurred at the clinic level. Multilevel Cox regression and spatial analysis were used to estimate effects of various factors on TTR and assess model assumptions, respectively. Results TTR increased as neighborhood deprivation increased. After adjustment for age, friend social support, education and healthcare status, the TTR among women living in a neighborhood with a moderate median household income (between $36,147 and $53,099) was shorter compared to women living in low median household income neighborhoods (< $36,147) (p < 0.05). There is little evidence that unmeasured confounders are geographically patterned. Conclusions Increased neighborhood socioeconomic deprivation was associated with longer TTR following an abnormal breast or cervical cancer screening test. Impact These results highlight the need for addressing patient- and neighborhood-level factors to reduce cancer disparities among underserved populations. PMID:25205516

  13. Association between chronic stress-induced structural abnormalities in Ranvier nodes and reduced oligodendrocyte activity in major depression

    PubMed Central

    Miyata, Shingo; Taniguchi, Manabu; Koyama, Yoshihisa; Shimizu, Shoko; Tanaka, Takashi; Yasuno, Fumihiko; Yamamoto, Akihide; Iida, Hidehiro; Kudo, Takashi; Katayama, Taiichi; Tohyama, Masaya

    2016-01-01

    Repeated stressful events are associated with the onset of major depressive disorder (MDD). We previously showed oligodendrocyte (OL)-specific activation of the serum/glucocorticoid-regulated kinase (SGK)1 cascade, increased expression of axon-myelin adhesion molecules, and elaboration of the oligodendrocytic arbor in the corpus callosum of chronically stressed mice. In the current study, we demonstrate that the nodes and paranodes of Ranvier in the corpus callosum were narrower in these mice. Chronic stress also led to diffuse redistribution of Caspr and Kv 1.1 and decreased the activity in white matter, suggesting a link between morphological changes in OLs and inhibition of axonal activity. OL primary cultures subjected to chronic stress resulted in SGK1 activation and translocation to the nucleus, where it inhibited the transcription of metabotropic glutamate receptors (mGluRs). Furthermore, the cAMP level and membrane potential of OLs were reduced by chronic stress exposure. We showed by diffusion tensor imaging that the corpus callosum of patients with MDD exhibited reduced fractional anisotropy, reflecting compromised white matter integrity possibly caused by axonal damage. Our findings suggest that chronic stress disrupts the organization of the nodes of Ranvier by suppressing mGluR activation in OLs, and that specific white matter abnormalities are closely associated with MDD onset. PMID:26976207

  14. α-Synuclein dimerization in erythrocytes of Gaucher disease patients: correlation with lipid abnormalities and oxidative stress.

    PubMed

    Moraitou, Marina; Dermentzaki, Georgia; Dimitriou, Evangelia; Monopolis, Ioannis; Dekker, Nick; Aerts, Hans; Stefanis, Leonidas; Michelakakis, Helen

    2016-02-01

    Several observations suggest that disturbed homeostasis of α-Synuclein (α-Syn) may provide a link between Gaucher disease (GD) and Parkinson's disease (PD). We recently reported increased dimerization of α-Syn in the red blood cell (RBC) membrane of patients with GD. Several studies indicate a crucial relationship between lipids, oxidative stress and α-Syn status. Here we investigated the relationship between the observed increased dimerization of α-Syn in the cell membranes of RBCs, cells devoid of lysosomes and lacking lysosomal enzyme synthesis, and the lipid abnormalities and oxidative stress already described in GD. Correlation studies showed that in GD the α-Syn dimer/monomer ratio is positively correlated with the levels of glucosylceramide (GlcCer) and the glucosylceramide/ceramide (GlcCer/Cer) ratio and negatively with the levels of malonyldialdehyde (MDA) and plasmalogens. In conclusion, we have shown that the increased tendency of α-Syn to form dimers in the RBC membrane of patients with GD, is correlated with both the level of lipids, including GlcCer, the primary lipid abnormality in GD, and the increased oxidative stress observed in this disorder. The study of other tissues, and in particular brain, will be important in order to elucidate the significance of these findings regarding the link between GD and PD. PMID:26708635

  15. 40 CFR 91.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Catalyst thermal stress test. 91.329....329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for termally stressing the... stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture must have the...

  16. 40 CFR 91.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Catalyst thermal stress test. 91.329....329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for termally stressing the... stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture must have the...

  17. 40 CFR 91.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Catalyst thermal stress test. 91.329....329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for termally stressing the... stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture must have the...

  18. 40 CFR 91.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress test. 91.329....329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for termally stressing the... stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture must have the...

  19. 40 CFR 91.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Catalyst thermal stress test. 91.329....329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for termally stressing the... stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture must have the...

  20. Provider management strategies of abnormal test result alerts: a cognitive task analysis

    PubMed Central

    Sawhney, Mona K; Wilson, Lindsay; Sittig, Dean F; Espadas, Donna; Davis, Traber; Singh, Hardeep

    2010-01-01

    Objective Electronic medical records (EMRs) facilitate abnormal test result communication through “alert” notifications. The aim was to evaluate how primary care providers (PCPs) manage alerts related to critical diagnostic test results on their EMR screens, and compare alert-management strategies of providers with high versus low rates of timely follow-up of results. Design 28 PCPs from a large, tertiary care Veterans Affairs Medical Center (VAMC) were purposively sampled according to their rates of timely follow-up of alerts, determined in a previous study. Using techniques from cognitive task analysis, participants were interviewed about how and when they manage alerts, focusing on four alert-management features to filter, sort and reduce unnecessary alerts on their EMR screens. Results Provider knowledge of alert-management features ranged between 4% and 75%. Almost half (46%) of providers did not use any of these features, and none used more than two. Providers with higher versus lower rates of timely follow-up used the four features similarly, except one (customizing alert notifications). Providers with low rates of timely follow-up tended to manually scan the alert list and process alerts heuristically using their clinical judgment. Additionally, 46% of providers used at least one workaround strategy to manage alerts. Conclusion Considerable heterogeneity exists in provider use of alert-management strategies; specific strategies may be associated with lower rates of timely follow-up. Standardization of alert-management strategies including improving provider knowledge of appropriate tools in the EMR to manage alerts could reduce the lack of timely follow-up of abnormal diagnostic test results. PMID:20064805

  1. Cancer, reproductive abnormalities, and diabetes in Micronesia: the effect of nuclear testing.

    PubMed

    Yamada, Seiji

    2004-09-01

    Many suggest that cancer and other diseases in Micronesia have been caused by nuclear testing in the Pacific. The 50-year commemoration of the March 1, 1954 Bravo thermonuclear test has rekindled interest in this area. This paper explores the documentation for, and the plausibility of, claims for disease causation by nuclear testing. Given the sheer volume of testing that the US conducted in the Pacific, it appears plausible that excess cancer would have occurred in areas of Micronesia other than the Marshall Islands. An excess of birth abnormalities in the Marshall Islands has been documented. While diabetes is not a radiogenic disease, and other cancers are generally less radiogenic than leukemia or thyroid cancer, the social and cultural effects of nuclear testing specifically, and the strategic uses to which Micronesia has been put generally, have had roles in the social production of disease. Integration into a globalized, cosmopolitan economy-with attendant phenomena such as the importation of tobacco, alcohol, foods of poor nutritional value, and new cultural morés-are also factors. PMID:16281703

  2. The use of antioxidative stress enzymes, lipid peroxidation, and red blood cell abnormalities as biomarkers of stress in Periphthalmus papilio of the polluted coastal Lagos lagoon.

    PubMed

    Nnamdi, Amaeze H; Olumide, Adebesin A; Adeladun, Adepegba E; Oyenike, Kolapo; Rosemary, Egonmwan I

    2015-03-01

    We assessed the mudskipper, Periphthalmus papilio inhabiting the coast line of the Lagos lagoon, Gulf of Guinea, to determine suitable biomarkers of stress due to its current status as a polluted water body. The gill and liver samples showed evidence of some activities of antioxidative stress enzymes including catalase, superoxide dismutase, glutathione-s-transferase, reduced glutahthione, as well as some detectable levels of lipid peroxidation product. The stress status of the fishes was also elucidated by nuclear abnormalities especially micronucleus formation and the presence of numerous vacuolated red blood cells. Given the current need for more sensitive bioindicators in monitoring pollution in this lagoon, we hereby present these inherent responses in P. papilio as a suitable candidate for incorporation into the current repertoire for ecotoxicological investigations in polluted water bodies of the Gulf of Guinea coastline. PMID:25666650

  3. Abnormal TREC-Based Newborn Screening Test in a Premature Neonate with Massive Perivillous Fibrin Deposition of the Placenta

    PubMed Central

    Kostadinov, Stefan; Robbins, Karen A.; Hayward, Anthony

    2016-01-01

    Severe combined immunodeficiency (SCID), a primary immunodeficiency arising from variable defects in lymphocyte development and survival, is characterized by significant deficiency of thymus derived (T-) lymphocytes and variable defects in the B-lymphocyte population. Newborn screening for SCID is based on detection of low numbers of T-cell receptor excision circles (TRECs) by real time quantitative PCR (RT-qPCR). This screening allows for early identification of individuals with SCID and other disorders characterized by T-lymphopenia. Higher rates of abnormal screens are commonly seen in premature and critically ill neonates, often representing false positives. It is possible that many abnormal screens seen in these populations are result of conditions that are characterized by systemic inflammation or stress, possibly in the context of stress-induced thymic involution. We present a case of a male infant delivered at 27 weeks, 6 days of gestation, with severe intrauterine growth restriction who had an abnormal TREC screen and a massive perivillous fibrin deposition (MPFD) of the placenta. This association has not been reported previously. We are raising the awareness to the fact that conditions, such as MPFD, that can create adverse intrauterine environment are capable of causing severe stress-induced thymic involution of the fetus which can present with abnormal TREC results on newborn screening. PMID:27403355

  4. Abnormal TREC-Based Newborn Screening Test in a Premature Neonate with Massive Perivillous Fibrin Deposition of the Placenta.

    PubMed

    Kostadinov, Stefan; Robbins, Karen A; Hayward, Anthony

    2016-01-01

    Severe combined immunodeficiency (SCID), a primary immunodeficiency arising from variable defects in lymphocyte development and survival, is characterized by significant deficiency of thymus derived (T-) lymphocytes and variable defects in the B-lymphocyte population. Newborn screening for SCID is based on detection of low numbers of T-cell receptor excision circles (TRECs) by real time quantitative PCR (RT-qPCR). This screening allows for early identification of individuals with SCID and other disorders characterized by T-lymphopenia. Higher rates of abnormal screens are commonly seen in premature and critically ill neonates, often representing false positives. It is possible that many abnormal screens seen in these populations are result of conditions that are characterized by systemic inflammation or stress, possibly in the context of stress-induced thymic involution. We present a case of a male infant delivered at 27 weeks, 6 days of gestation, with severe intrauterine growth restriction who had an abnormal TREC screen and a massive perivillous fibrin deposition (MPFD) of the placenta. This association has not been reported previously. We are raising the awareness to the fact that conditions, such as MPFD, that can create adverse intrauterine environment are capable of causing severe stress-induced thymic involution of the fetus which can present with abnormal TREC results on newborn screening. PMID:27403355

  5. Fluid shear stress as a regulator of gene expression in vascular cells: possible correlations with diabetic abnormalities

    NASA Technical Reports Server (NTRS)

    Papadaki, M.; Eskin, S. G.; Ruef, J.; Runge, M. S.; McIntire, L. V.

    1999-01-01

    Diabetes mellitus is associated with increased frequency, severity and more rapid progression of cardiovascular diseases. Metabolic perturbations from hyperglycemia result in disturbed endothelium-dependent relaxation, activation of coagulation pathways, depressed fibrinolysis, and other abnormalities in vascular homeostasis. Atherosclerosis is localized mainly at areas of geometric irregularity at which blood vessels branch, curve and change diameter, and where blood is subjected to sudden changes in velocity and/or direction of flow. Shear stress resulting from blood flow is a well known modulator of vascular cell function. This paper presents what is currently known regarding the molecular mechanisms responsible for signal transduction and gene regulation in vascular cells exposed to shear stress. Considering the importance of the hemodynamic environment of vascular cells might be vital to increasing our understanding of diabetes.

  6. Intervention to Improve Follow-up for Abnormal Papanicolaou Tests: A Randomized Clinical Trial

    PubMed Central

    Breitkopf, Carmen Radecki; Dawson, Lauren; Grady, James J.; Breitkopf, Daniel M.; Nelson-Becker, Carolyn; Snyder, Russell R.

    2014-01-01

    Objective To evaluate the effect of a theory-based, culturally-targeted intervention on adherence to follow-up among low-income and minority women who experience an abnormal Pap test. Methods 5,049 women were enrolled and underwent Pap testing. Of these, 378 had an abnormal result and 341 (90%) were randomized to 1 of 3 groups to receive their results: Intervention (I): culturally-targeted behavioral and normative beliefs + knowledge/skills + salience + environmental constraints/barriers counseling; Active Control (AC): non-targeted behavioral and normative beliefs + knowledge/skills + salience + environmental constraints/barriers counseling; or Standard Care Only (SCO). The primary outcome was attendance at the initial follow-up appointment. Secondary outcomes included delay in care, completion of care at 18 months, state anxiety (STAI Y-6), depressive symptoms (CES-D), and distress (CDDQ). Anxiety was assessed at enrollment, notification of results, and 7–14 days later with the CDDQ and CES-D. Results 299 women were included in intent-to-treat analyses. Adherence rates were 60% (I), 54% (AC), and 58% (SCO), p=0.73. Completion rates were 39% (I) and 35% in the AC and SCO groups, p=0.77. Delay in care (in days) was (M ±SD): 58 ±75 (I), 69 ±72 (AC), and 54 ±75 (SCO), p=0.75. Adherence was associated with higher anxiety at notification, p<0.01 while delay <90 days (vs. 90+) was associated with greater perceived personal responsibility, p<0.05. Women not completing their care (vs. those who did) had higher CES-D scores at enrollment, p<0.05. Conclusions A theory-based, culturally-targeted message was not more effective than a non-targeted message or standard care in improving behavior. PMID:23730719

  7. Post-weaning social isolation induces abnormal forms of aggression in conjunction with increased glucocorticoid and autonomic stress responses.

    PubMed

    Toth, Mate; Mikics, Eva; Tulogdi, Aron; Aliczki, Mano; Haller, Jozsef

    2011-06-01

    We showed earlier that social isolation from weaning (a paradigm frequently used to model social neglect in children) induces abnormal forms of attack in rats, and assumed that these are associated with hyperarousal. To investigate this hypothesis, we deprived rats of social contacts from weaning and studied their behavior, glucocorticoid and autonomic stress responses in the resident-intruder paradigm at the age of 82 days. Social isolation resulted in abnormal attack patterns characterized by attacks on vulnerable targets, deficient social communication and increased defensive behaviors (defensive upright, flight, freezing). During aggressive encounters, socially deprived rats rapidly switched from one behavior to another, i.e. showed an increased number of behavioral transitions as compared to controls. We tentatively term this behavioral feature "behavioral fragmentation" and considered it a form of behavioral arousal. Basal levels of plasma corticosterone regularly assessed by radioimmunoassay between 27 and 78 days of age were not affected. In contrast, aggression-induced glucocorticoid responses were approximately doubled by socially isolation. Diurnal oscillations in heart rate assessed by in vivo biotelemetry were not affected by social isolation. In contrast, the aggression-induced increase in heart rate was higher in socially isolated than in socially housed rats. Thus, post-weaning social isolation induced abnormal forms of aggression that developed on the background of increased behavioral, endocrine and autonomic arousal. We suggest that this paradigm may be used to model aggression-related psychopathologies associated with hyperarousal, particularly those that are triggered by adverse rearing conditions.

  8. 12 CFR 652.40 - Stress tests for mortgage securities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Stress tests for mortgage securities. 652.40... MORTGAGE CORPORATION FUNDING AND FISCAL AFFAIRS Investment Management § 652.40 Stress tests for mortgage securities. (a) You must perform stress tests to determine how interest rate changes will affect the...

  9. 12 CFR 252.148 - Disclosure of stress test results.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Disclosure of stress test results. 252.148... RESERVE SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered Companies § 252.148 Disclosure of stress test results. (a) Public disclosure...

  10. 12 CFR 1238.3 - Annual stress test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Annual stress test. 1238.3 Section 1238.3 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ENTITY REGULATIONS STRESS TESTING OF REGULATED ENTITIES § 1238.3 Annual stress test. (a) In general. Each regulated entity: (1) Shall complete an annual...

  11. 12 CFR 252.148 - Disclosure of stress test results.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Disclosure of stress test results. 252.148... RESERVE SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered Companies § 252.148 Disclosure of stress test results. (a) Public disclosure...

  12. 12 CFR 252.157 - Disclosure of stress test results.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Disclosure of stress test results. 252.157... RESERVE SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test... Companies § 252.157 Disclosure of stress test results. (a) Public disclosure of results—(1) In general....

  13. 12 CFR 652.40 - Stress tests for mortgage securities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Stress tests for mortgage securities. 652.40... MORTGAGE CORPORATION FUNDING AND FISCAL AFFAIRS Investment Management § 652.40 Stress tests for mortgage securities. (a) You must perform stress tests to determine how interest rate changes will affect the...

  14. 12 CFR 652.40 - Stress tests for mortgage securities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Stress tests for mortgage securities. 652.40... MORTGAGE CORPORATION FUNDING AND FISCAL AFFAIRS Investment Management § 652.40 Stress tests for mortgage securities. (a) You must perform stress tests to determine how interest rate changes will affect the...

  15. 12 CFR 252.157 - Disclosure of stress test results.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Disclosure of stress test results. 252.157... RESERVE SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test... Companies § 252.157 Disclosure of stress test results. (a) Public disclosure of results—(1) In general....

  16. 12 CFR 652.40 - 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. 652.40... MORTGAGE CORPORATION FUNDING AND FISCAL AFFAIRS Investment Management § 652.40 Stress tests for mortgage securities. (a) You must perform stress tests to determine how interest rate changes will affect the...

  17. Trier’s Social Stress Test for children: testing the methodology for Indian adolescents

    PubMed Central

    Krishnaveni, GV; Veena, SR; Jones, A; Bhat, DS; Malathi, MP; Hellhammer, D; Srinivasan, K; Upadya, H; Kurpad, AV; Fall, CHD

    2014-01-01

    Objective Abnormal cortisol and autonomic stress responses may increase risks of adult chronic disease. With its growing burden of chronic disease, India is an important setting to determine mechanisms for this, but the utility of existing psychological stressors for research in this population is unknown. We tested the Trier Social Stress Test for children (TSST-C), developed for European children, in a cohort of Indian adolescents. Design Cohort study Setting Holdsworth Memorial Hospital, Mysore, India. Subjects Adolescent children (N=273, 134 males; mean age 13.6 years) selected from an ongoing birth cohort. Methods The children performed 5-minutes each of public speaking and mental arithmetic tasks in front of two unfamiliar ‘evaluators’, which formed the stressor (TSST-C). Salivary cortisol concentrations were measured at baseline and at regular intervals after the TSST-C. Continuous measurements of heart rate, finger blood pressure (BP), stroke volume, cardiac output and systemic vascular resistance (SVR) were carried out before, during and for 10 minutes after the TSST-C using a finger cuff. Results TSST-C was completed in 269 children. Cortisol concentrations (mean increment (SD): 6.1 (6.9) ng/ml), and heart rate (4.6 (10.1) bpm), systolic (24.2 (11.6) mmHg) and diastolic BP (16.5 (7.3) mmHg), cardiac output (0.6 (0.7) L/min), stroke volume (4.0 (5.6) ml) and SVR (225 (282) dyn.s/cm5) increased significantly from baseline after inducing stress (P<0.001 for all). Conclusions The TSST-C produces stress responses in Indian adolescents of a sufficient magnitude to be a useful tool for examining stress physiology and its relationships to disease outcomes in this population. PMID:24986282

  18. Usefulness of noninvasive detection of left ventricular diastolic abnormalities during isometric stress in hypertrophic cardiomyopathy and in athletes.

    PubMed

    Manolas, J; Kyriakidis, M; Anastasakis, A; Pegas, P; Rigopoulos, A; Theopistou, A; Toutouzas, P

    1998-02-01

    We showed previously that the handgrip apexcardiographic test (HAT) is a useful method for detecting left ventricular (LV) diastolic abnormalities in patients with coronary artery disease and systemic hypertension. This study evaluates the use of HAT for assessing the prevalence and types of exercise-induced diastolic abnormalities in patients with obstructive (n = 31) and nonobstructive (n = 35) hypertrophic cardiomyopathy (HC) as well as its potential value for separating healthy subjects and athletes from patients with HC. We obtained a HAT in 66 consecutive patients with HC and in 72 controls (52 healthy volunteers and 20 athletes). A positive HAT was defined by the presence of one of the following: (1) relative A wave to total height (A/H) during or after handgrip > 21% (compliance type), (2) total apexcardiographic relaxation time (TART) > 143 ms or the heart rate corrected TART (TARTI) during handgrip < 0.14, (relaxation type), (3) both types present (mixed type), and (4) diastolic amplitude time index (DATI = TARTI/[A/D]) during handgrip < 0.27. Of the controls, only 1 of 52 healthy subjects and 1 of 20 athletes showed a positive HAT, whereas of the total HC cohort 63 of 66 patients (95%) had a positive result. There was no significant difference in the distribution of these types between obstructive and nonobstructive HC. Further, no LV diastolic abnormalities were present in 10 of 35 patients (29%) with nonobstructive HC at rest and in 3 of 35 patients (9%) during handgrip, whereas of the patients with obstructive HC only 1 of 31 (3%) had no LV diastolic abnormalities at rest and none during handgrip. Based on HAT data, our study demonstrates that in HC (1) LV diastolic abnormalities are very frequent during handgrip; (2) patients with nonobstructive HC show significantly fewer LV diastolic abnormalities at rest than those with obstructive HC; and (3) no significant difference exists between obstructive and nonobstructive HC in the prevalence of types of

  19. Treadmill exercise tests predischarge and six weeks post-myocardial infarction to detect abnormalities of known prognostic value.

    PubMed

    Starling, M R; Crawford, M H; Kennedy, G T; O'Rourke, R A

    1981-06-01

    We evaluated 89 patients with predischarge and 6-week post-myocardial infarction treadmill exercise tests to determine the importance of doing repeat tests to identify abnormalities of known prognostic value, and assess the individual variability of treadmill abnormality responses. Nineteen patients (21%) completed only a predischarge exercise test, nine of whom experienced an early cardiac event precluding repeat testing. All nine had a prognostically important treadmill abnormality during the predischarge test. Electrocardiographic ST segment depression was highly reproducible between the early and 6-week tests (k = 0.968). However, angina, inadequate blood pressure response, and ventricular arrhythmias showed limited reproducibility (k = 0.344, 0.50, and 0.166, respectively) and substantial individual variability. Thus, we concluded that: a predischarge treadmill exercise test is important for determining the immediate short-term prognosis of patients after myocardial infarction; and ST segment depression is highly reproducible, whereas other treadmill abnormality responses show substantial variability between the predischarge and 6-week tests.

  20. Do abnormal hemipelvic bone stresses contribute to loosening and migration of screw-threaded cups?

    PubMed

    Learmonth, I D; Spirakis, A

    1994-03-01

    Excellent long-term results have been reported with the Charnley low-friction arthroplasty. Failure of the cemented acetabular component has been identified as a problem in the longer term, while cemented hip replacements in active young patients have exhibited a disconcerting incidence of early clinical or radiological failure. This resulted in the development of the cementless arthroplasty. Bone responds favourably to an optimal stress window and reacts dynamically to metal implants that have a greatly differing modulus of elasticity. This study represents a comparative qualitative analysis of the peri-acetabular hemipelvic stresses after loading two cementless (press-fit and screw-threaded) acetabular components inserted into identical bone models. A simplified model of the artificial hip joint was constructed and the very sensitive stress analysis technique of holographic interferometry was used for the investigation. Peri-acetabular stress concentrations were noted with the screw-threaded cup. This may predispose to bone resorption and it is suggested that these could be implicated in the migration of these cups described in published reports.

  1. 40 CFR 90.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress test. 90.329... Equipment Provisions § 90.329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for... effect of thermal stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture...

  2. 40 CFR 90.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Catalyst thermal stress test. 90.329... Equipment Provisions § 90.329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for... effect of thermal stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture...

  3. 40 CFR 90.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Catalyst thermal stress test. 90.329... Equipment Provisions § 90.329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for... effect of thermal stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture...

  4. 40 CFR 90.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Catalyst thermal stress test. 90.329... Equipment Provisions § 90.329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for... effect of thermal stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture...

  5. 40 CFR 90.329 - Catalyst thermal stress test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Catalyst thermal stress test. 90.329... Equipment Provisions § 90.329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for... effect of thermal stress on catalyst conversion efficiency. (2) The synthetic exhaust gas mixture...

  6. White Matter Abnormalities in Post-traumatic Stress Disorder Following a Specific Traumatic Event

    PubMed Central

    Li, Lei; Lei, Du; Li, Lingjiang; Huang, Xiaoqi; Suo, Xueling; Xiao, Fenglai; Kuang, Weihong; Li, Jin; Bi, Feng; Lui, Su; Kemp, Graham J.; Sweeney, John A.; Gong, Qiyong

    2016-01-01

    Studies of posttraumatic stress disorder (PTSD) are complicated by wide variability in the intensity and duration of prior stressors in patient participants, secondary effects of chronic psychiatric illness, and a variable history of treatment with psychiatric medications. In magnetic resonance imaging (MRI) studies, patient samples have often been small, and they were not often compared to similarly stressed patients without PTSD in order to control for general stress effects. Findings from these studies have been inconsistent. The present study investigated whole-brain microstructural alterations of white matter in a large drug-naive population who survived a specific, severe traumatic event (a major 8.0-magnitude earthquake). Using diffusion tensor imaging (DTI), we explored group differences between 88 PTSD patients and 91 matched traumatized non-PTSD controls in fractional anisotropy (FA), as well as its component elements axial diffusivity (AD) and radial diffusivity (RD), and examined these findings in relation to findings from deterministic DTI tractography. Relations between white matter alterations and psychiatric symptom severity were examined. PTSD patients, relative to similarly stressed controls, showed an FA increase as well as AD and RD changes in the white matter beneath left dorsolateral prefrontal cortex and forceps major. The observation of increased FA in the PTSD group suggests that the pathophysiology of PTSD after a specific acute traumatic event is distinct from what has been reported in patients with several years duration of illness. Alterations in dorsolateral prefrontal cortex may be an important aspect of illness pathophysiology, possibly via the region's established role in fear extinction circuitry. Use-dependent myelination or other secondary compensatory changes in response to heightened demands for threat appraisal and emotion regulation may be involved. PMID:26981581

  7. White Matter Abnormalities in Post-traumatic Stress Disorder Following a Specific Traumatic Event.

    PubMed

    Li, Lei; Lei, Du; Li, Lingjiang; Huang, Xiaoqi; Suo, Xueling; Xiao, Fenglai; Kuang, Weihong; Li, Jin; Bi, Feng; Lui, Su; Kemp, Graham J; Sweeney, John A; Gong, Qiyong

    2016-02-01

    Studies of posttraumatic stress disorder (PTSD) are complicated by wide variability in the intensity and duration of prior stressors in patient participants, secondary effects of chronic psychiatric illness, and a variable history of treatment with psychiatric medications. In magnetic resonance imaging (MRI) studies, patient samples have often been small, and they were not often compared to similarly stressed patients without PTSD in order to control for general stress effects. Findings from these studies have been inconsistent. The present study investigated whole-brain microstructural alterations of white matter in a large drug-naive population who survived a specific, severe traumatic event (a major 8.0-magnitude earthquake). Using diffusion tensor imaging (DTI), we explored group differences between 88 PTSD patients and 91 matched traumatized non-PTSD controls in fractional anisotropy (FA), as well as its component elements axial diffusivity (AD) and radial diffusivity (RD), and examined these findings in relation to findings from deterministic DTI tractography. Relations between white matter alterations and psychiatric symptom severity were examined. PTSD patients, relative to similarly stressed controls, showed an FA increase as well as AD and RD changes in the white matter beneath left dorsolateral prefrontal cortex and forceps major. The observation of increased FA in the PTSD group suggests that the pathophysiology of PTSD after a specific acute traumatic event is distinct from what has been reported in patients with several years duration of illness. Alterations in dorsolateral prefrontal cortex may be an important aspect of illness pathophysiology, possibly via the region's established role in fear extinction circuitry. Use-dependent myelination or other secondary compensatory changes in response to heightened demands for threat appraisal and emotion regulation may be involved. PMID:26981581

  8. Diode step stress testing program for JANTX1N5550

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The effect was studied of power/temperature step stress when applied to the switching diode JANTX1N5550 manufactured by Semtech and Micro Semiconductor. The power/temperature stress tests are presented, and failure analyses are included.

  9. Abnormal hippocampal morphology in dissociative identity disorder and post-traumatic stress disorder correlates with childhood trauma and dissociative symptoms.

    PubMed

    Chalavi, Sima; Vissia, Eline M; Giesen, Mechteld E; Nijenhuis, Ellert R S; Draijer, Nel; Cole, James H; Dazzan, Paola; Pariante, Carmine M; Madsen, Sarah K; Rajagopalan, Priya; Thompson, Paul M; Toga, Arthur W; Veltman, Dick J; Reinders, Antje A T S

    2015-05-01

    Smaller hippocampal volume has been reported in individuals with post-traumatic stress disorder (PTSD) and dissociative identity disorder (DID), but the regional specificity of hippocampal volume reductions and the association with severity of dissociative symptoms and/or childhood traumatization are still unclear. Brain structural magnetic resonance imaging scans were analyzed for 33 outpatients (17 with DID and 16 with PTSD only) and 28 healthy controls (HC), all matched for age, sex, and education. DID patients met criteria for PTSD (PTSD-DID). Hippocampal global and subfield volumes and shape measurements were extracted. We found that global hippocampal volume was significantly smaller in all 33 patients (left: 6.75%; right: 8.33%) compared with HC. PTSD-DID (left: 10.19%; right: 11.37%) and PTSD-only with a history of childhood traumatization (left: 7.11%; right: 7.31%) had significantly smaller global hippocampal volume relative to HC. PTSD-DID had abnormal shape and significantly smaller volume in the CA2-3, CA4-DG and (pre)subiculum compared with HC. In the patient groups, smaller global and subfield hippocampal volumes significantly correlated with higher severity of childhood traumatization and dissociative symptoms. These findings support a childhood trauma-related etiology for abnormal hippocampal morphology in both PTSD and DID and can further the understanding of neurobiological mechanisms involved in these disorders. PMID:25545784

  10. Abnormal hippocampal morphology in dissociative identity disorder and post-traumatic stress disorder correlates with childhood trauma and dissociative symptoms.

    PubMed

    Chalavi, Sima; Vissia, Eline M; Giesen, Mechteld E; Nijenhuis, Ellert R S; Draijer, Nel; Cole, James H; Dazzan, Paola; Pariante, Carmine M; Madsen, Sarah K; Rajagopalan, Priya; Thompson, Paul M; Toga, Arthur W; Veltman, Dick J; Reinders, Antje A T S

    2015-05-01

    Smaller hippocampal volume has been reported in individuals with post-traumatic stress disorder (PTSD) and dissociative identity disorder (DID), but the regional specificity of hippocampal volume reductions and the association with severity of dissociative symptoms and/or childhood traumatization are still unclear. Brain structural magnetic resonance imaging scans were analyzed for 33 outpatients (17 with DID and 16 with PTSD only) and 28 healthy controls (HC), all matched for age, sex, and education. DID patients met criteria for PTSD (PTSD-DID). Hippocampal global and subfield volumes and shape measurements were extracted. We found that global hippocampal volume was significantly smaller in all 33 patients (left: 6.75%; right: 8.33%) compared with HC. PTSD-DID (left: 10.19%; right: 11.37%) and PTSD-only with a history of childhood traumatization (left: 7.11%; right: 7.31%) had significantly smaller global hippocampal volume relative to HC. PTSD-DID had abnormal shape and significantly smaller volume in the CA2-3, CA4-DG and (pre)subiculum compared with HC. In the patient groups, smaller global and subfield hippocampal volumes significantly correlated with higher severity of childhood traumatization and dissociative symptoms. These findings support a childhood trauma-related etiology for abnormal hippocampal morphology in both PTSD and DID and can further the understanding of neurobiological mechanisms involved in these disorders.

  11. Modification of the association of bisphenol A with abnormal liver function by polymorphisms of oxidative stress-related genes.

    PubMed

    Kim, Jin Hee; Lee, Mee-Ri; Hong, Yun-Chul

    2016-05-01

    Some studies suggested oxidative stress as a possible mechanism for the relation between exposure to bisphenol A (BPA) and liver damage. Therefore, we evaluated modification of genetic polymorphisms of cyclooxygenase 2 (COX2 or PTGS2), epoxide hydrolase 1 (EPHX1), catalase (CAT), and superoxide dismutase 2 (SOD2 or MnSOD), which are oxidative stress-related genes, on the relation between exposure to BPA and liver function in the elderly. We assessed the association of visit-to-visit variations in BPA exposure with abnormal liver function by each genotype or haplotype after controlling for age, sex, BMI, alcohol consumption, exercise, urinary cotinine levels, and low density lipoprotein cholesterol using a GLIMMIX model. A significant association of BPA with abnormal liver function was observed only in participants with COX2 GG genotype at rs5277 (odds ratio (OR)=3.04 and p=0.0231), CAT genotype at rs769218 (OR=4.16 and p=0.0356), CAT CT genotype at rs769217 (OR=4.19 and p=0.0348), SOD2 TT genotype at rs4880 (OR=2.59 and p=0.0438), or SOD2 GG genotype at rs2758331 (OR=2.57 and p=0.0457). Moreover, we also found higher OR values in participants with a pair of G-G haplotypes for COX2 (OR=2.81 and p=0.0384), G-C-A haplotype for EPHX1 (OR=4.63 and p=0.0654), A-T haplotype for CAT (OR=4.48 and p=0.0245), or T-G-A haplotype for SOD2 (OR=2.91 and p=0.0491) compared with those with the other pair of haplotypes for each gene. Furthermore, the risk score composed of 4 risky pair of haplotypes showed interactive effect with BPA on abnormal liver function (p=0.0057). Our study results suggest that genetic polymorphisms of COX2, EPHX1, CAT, and SOD2 modify the association of BPA with liver function. PMID:26922413

  12. High temperature aqueous stress corrosion testing device

    DOEpatents

    Bornstein, A.N.; Indig, M.E.

    1975-12-01

    A description is given of a device for stressing tensile samples contained within a high temperature, high pressure aqueous environment, thereby permitting determination of stress corrosion susceptibility of materials in a simple way. The stressing device couples an external piston to an internal tensile sample via a pull rod, with stresses being applied to the sample by pressurizing the piston. The device contains a fitting/seal arrangement including Teflon and weld seals which allow sealing of the internal system pressure and the external piston pressure. The fitting/seal arrangement allows free movement of the pull rod and the piston.

  13. Squatting test: A posture to study and counteract cardiovascular abnormalities associated with autonomic dysfunction.

    PubMed

    Philips, Jean-Christophe; Scheen, André J

    2011-07-01

    The squatting test is an active posture manoeuvre that imposes one of the most potent orthostatic stresses. In normal subjects, the changes in blood pressure and heart rate are transient because of appropriate baroreflex homeostasis and do not provoke symptoms. However, in various pathological conditions, both the increase in blood pressure during squatting and the decrease in blood pressure during standing may be more important and sustained, potentially leading to complaints and adverse events. Squatting has been used to evaluate patients with tetralogy of Fallot, heart transplant, dysautonomia, including diabetic cardiovascular autonomic neuropathy, and individuals prone to vasovagal syncope. Careful analysis of changes in blood pressure and heart rate during the transition from standing to squatting and from squatting to standing allows the early detection of altered vagal and/or sympathetic function. Of note squatting position has been proposed as a therapeutic means to counteract the fall in blood pressure in patients suffering from dizziness due to dysautonomia and orthostatic hypotension or presenting pre-syncope symptoms, such as soon after exercise. The aims of the present review are to analyse the haemodynamic pattern during a squatting test in various pathological situations and to describe what may be the negative and positive haemodynamic changes associated with this posture. We were especially interested in using the squatting test for the assessment of cardiovascular autonomic neuropathy associated with diabetes mellitus.

  14. Relation between increased oxidative stress and histological abnormalities in the ovaries of Alburnus tarichi in Lake Van, Turkey.

    PubMed

    Kaptaner, Burak

    2015-11-01

    Recent studies have shown reproductively arrested gonad development in female Alburnus tarichi (Güldenstädt, 1814) (Cyprinidae) from the eastern coastline of Lake Van, Turkey, due to increasing pollution. In the reproductively arrested females (RAF), oocytes were developmentally blocked and arrested at the previtellogenic stage and gonadosomatic indices (GSI) were very low, while reproductively non-arrested females (RNF) found at the same site displayed relatively normal ovarian development and higher GSI. The present study investigated various oxidative stress biomarkers in the ovaries of RAF and RNF collected from a polluted site at Lake Van at the mid-vitellogenic phase, compared with reference fish from a non-polluted site (Lake Erçek). Ovarian total protein content, biometric indices, and histology were also evaluated. The oxidative stress biomarkers used were levels of lipid peroxidation (LPO) and glutathione (GSH), and activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST). High levels of LPO and GSH and activities of SOD, GPx and GST were found in the ovaries of RAF compared with the reference fish. GSH content and activities of GPx and GST were also higher in the RNF. The total protein content and biometric indices decreased significantly in the RAF compared with the RNF and reference fish. The histology of the ovaries revealed atresia, melano-macrophage centers, encapsulated follicle cysts, and severe fibrosis in the RAF. The results of this study suggest that abnormalities in the ovaries of A. tarichi are causally related to increased oxidative stress as a result of pollution. PMID:26497562

  15. Relation between increased oxidative stress and histological abnormalities in the ovaries of Alburnus tarichi in Lake Van, Turkey.

    PubMed

    Kaptaner, Burak

    2015-11-01

    Recent studies have shown reproductively arrested gonad development in female Alburnus tarichi (Güldenstädt, 1814) (Cyprinidae) from the eastern coastline of Lake Van, Turkey, due to increasing pollution. In the reproductively arrested females (RAF), oocytes were developmentally blocked and arrested at the previtellogenic stage and gonadosomatic indices (GSI) were very low, while reproductively non-arrested females (RNF) found at the same site displayed relatively normal ovarian development and higher GSI. The present study investigated various oxidative stress biomarkers in the ovaries of RAF and RNF collected from a polluted site at Lake Van at the mid-vitellogenic phase, compared with reference fish from a non-polluted site (Lake Erçek). Ovarian total protein content, biometric indices, and histology were also evaluated. The oxidative stress biomarkers used were levels of lipid peroxidation (LPO) and glutathione (GSH), and activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST). High levels of LPO and GSH and activities of SOD, GPx and GST were found in the ovaries of RAF compared with the reference fish. GSH content and activities of GPx and GST were also higher in the RNF. The total protein content and biometric indices decreased significantly in the RAF compared with the RNF and reference fish. The histology of the ovaries revealed atresia, melano-macrophage centers, encapsulated follicle cysts, and severe fibrosis in the RAF. The results of this study suggest that abnormalities in the ovaries of A. tarichi are causally related to increased oxidative stress as a result of pollution.

  16. Dermatoglyphics and abnormal palmar flexion creases as markers of early prenatal stress in children with idiopathic intellectual disability.

    PubMed

    Rosa, A; Gutiérrez, B; Guerra, A; Arias, B; Fañanás, L

    2001-10-01

    A number of studies have shown the importance of dermatoglyphics as markers of prenatal disturbance in developmental disorders of unknown origin. Genetic and non-genetic factors are involved in the aetiology of intellectual disability (ID), although the cause remains unknown in up to 50% of cases. The aim of the present study was to analyse dermatoglyphic traits and abnormal palmar flexion creases as markers of environmental prenatal stress in children with idiopathic ID (IID) using a case-control study design. Three dermatoglyphic variables, which have been reported as altered in other congenital disorders, were considered were studied in a sample of 62 children with IID (IQ < 70) and 75 healthy controls (IQ > 70): (1) fingerprint patterns; (2) total a-b ridge count (TABRC); and (3) abnormal palmar flexion creases (APFCs). More arches, the simplest fingerprint pattern, and more radial loops, an unusual pattern, were found in IID cases in comparison to controls (chi23 = 9.26; P = 0.02), with especially marked differences in boys (chi23 = 6.5; P = 0.0008). A significant increase of APFCs was also found in the affected children (chi24 = 28.52; P < 0.00; odds ration = 3.86, 95% confidence interval = 1.77-8.47). For TABRC, the differences between IID cases and controls failed to reach the conventional level of significance. These findings suggest that environmental factors acting early in development, or mechanisms involving an interaction of genotype and environment could be involved in the aetiology of some cases of ID.

  17. Instrumented propellant block test and stress analysis comparison

    NASA Astrophysics Data System (ADS)

    Thompson, Richard E.; Perkins, Steven E.

    1992-02-01

    There is an on-going need to experimentally measure bond stresses in both termination stress and low-gradient stress areas of solid propellant rocket motors employing composite cases and having complex geometries. These measurements are needed to verify the finite element-predicted structural margins and environmental operating limits for these advanced tactical, strategic, and space motors. Chemical Systems Division undertook a program to develop stress transducers usable in low stress gradient regions and in termination, or high stress gradient, regions. The various transducers were evaluated in propellant blocks tested in tension and compression in the laboratory prior to being placed into structural test vehicles. Finite element analyses of the propellant test blocks were also performed to predict transducer response. The results of the instrumented propellant block tests are presented.

  18. Nondestructive Testing Residual Stress Using Ultrasonic Critical Refracted Longitudinal Wave

    NASA Astrophysics Data System (ADS)

    Xu, Chunguang; Song, Wentao; Pan, Qinxue; Li, Huanxin; Liu, Shuai

    Residual stress has significant impacts on the performance of the mechanical components, especially on its strength, fatigue life and corrosion resistance and dimensional stability. Based on theory of acoustoelasticity, the testing principle of ultrasonic LCR wave method is analyzed. The testing system of residual stress is build. The method of calibration of stress coefficient is proposed in order to improve the detection precision. At last, through experiments and applications on residual stress testing of oil pipeline weld joint, vehicle's torsion shaft, glass and ceramics, gear tooth root, and so on, the result show that it deserved to be studied deeply on application and popularization of ultrasonic LCR wave method.

  19. Evaluation of the Generalizability of the Number of Abnormal Scores and the Overall Test Battery Mean as Measures of Performance Validity to a Different Test Battery.

    PubMed

    Silk-Eglit, Graham M; Miele, Andrea S; Stenclik, Jessica H; Lynch, Julie K; McCaffrey, Robert J

    2015-01-01

    Davis, Axelrod, McHugh, Hanks, and Millis (2013) documented that in a battery of 25 tests, producing 15, 10, and 5 abnormal scores at 1, 1.5, and 2 standard deviations below the norm-referenced mean, respectively, and an overall test battery mean (OTBM) of T ≤ 38 accurately identifies performance invalidity. However, generalizability of these findings to other samples and test batteries remains unclear. This study evaluated the use of abnormal scores and the OTBM as performance validity measures in a different sample that was administered a 25-test battery that minimally overlapped with Davis et al.'s test battery. Archival analysis of 48 examinees with mild traumatic brain injury seen for medico-legal purposes was conducted. Producing 18 or more, 7 or more, and 5 or more abnormal scores at 1, 1.5, and 2 standard deviations below the norm-referenced mean, respectively, and an OTBM of T ≤ 40 most accurately classified examinees; however, using Davis et al.'s proposed cutoffs in the current sample maintained specificity at or near acceptable levels. Due to convergence across studies, producing ≥5 abnormal scores at 2 standard deviations below the norm-referenced mean is the most appropriate cutoff for clinical implementation; however, for batteries consisting of a different quantity of tests than 25, an OTBM of T ≤ 38 is more appropriate.

  20. Coping with the Stress of High Stakes Testing

    ERIC Educational Resources Information Center

    Kruger, Louis J.; Wandle, Caroline; Struzziero, Joan

    2007-01-01

    High stakes testing puts considerable pressure on schools, teachers, and students to achieve at high levels. Therefore, how schools and individuals cope with this major source of stress may have important implications for the success of high stakes testing. This article reviews relevant theory and research on stress as they relate to public…

  1. 77 FR 66566 - Stress Testing of Regulated Entities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-06

    ..., FHFA published for comment in the Federal Register a proposed rule, and invited comments. See 77 FR...; ] FEDERAL HOUSING FINANCE AGENCY 12 CFR Part 1238 RIN 2590-AA47 Stress Testing of Regulated Entities AGENCY... notice of proposed rulemaking for public comment concerning stress testing of the Federal...

  2. 12 CFR 252.147 - Reports of stress test results.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Information (12 CFR part 261). ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Reports of stress test results. 252.147 Section... SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements...

  3. 12 CFR 252.156 - Reports of stress test results.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ....C. 552(b)) and the Board's Rules Regarding Availability of Information (12 CFR part 261). ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Reports of stress test results. 252.156 Section... SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements...

  4. 77 FR 60948 - Stress Testing of Regulated Entities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-05

    ... Insurance Office while drafting this proposed rule. \\3\\ See 77 FR 594, 625-633, ``Enhanced Prudential Standards and Early Remediation Requirements for Covered Companies.'' \\4\\ 77 FR 3166, ``Annual Stress Test.'' \\5\\ 77 FR 3408, ``Annual Stress Test.'' V. Differences Between Banks and Enterprises Section 1313...

  5. 12 CFR 252.147 - Reports of stress test results.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Information Act (5 U.S.C. 552(b)) and the Board's Rules Regarding Availability of Information (12 CFR part 261). ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Reports of stress test results. 252.147 Section... SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements...

  6. 12 CFR 252.156 - Reports of stress test results.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ....C. 552(b)) and the Board's Rules Regarding Availability of Information (12 CFR part 261). ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Reports of stress test results. 252.156 Section... SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements...

  7. Disorders of sexual development and abnormal early development in domestic food-producing mammals: the role of chromosome abnormalities, environment and stress factors.

    PubMed

    Favetta, L A; Villagómez, D A F; Iannuzzi, L; Di Meo, G; Webb, A; Crain, S; King, W A

    2012-01-01

    The management of disorders of sexual development (DSD) in humans and domestic animals has been the subject of intense interest for decades. The association between abnormal chromosome constitutions and DSDs in domestic animals has been recorded since the beginnings of conventional cytogenetic analysis. Deviated karyotypes consisting of abnormal sex chromosome sets and/or the coexistence of cells with different sex chromosome constitutions in an individual seem to be the main causes of anomalies of sex determination and sex differentiation. In recent years, a growing interest has developed around the environmental insults, such as endocrine-disrupting compounds (EDC) and heat stressors, which affect fertility, early embryonic development and, in some instances, directly the sex ratio and/or the development of 1 specific sex versus the other. A variety of chemical compounds present in the environment at low doses has been shown to have major effects on the reproductive functions in human and domestic animals following prolonged exposure. In this review, we present an overview of congenital/chromosomal factors that are responsible for the DSDs and link them and the lack of proper embryonic development to environmental factors that are becoming a major global concern.

  8. Lessons learned: providing a mindfulness-based stress reduction program for low-income multiethnic women with abnormal pap smears.

    PubMed

    Abercrombie, Priscilla D; Zamora, Anita; Korn, Abner P

    2007-01-01

    Although the incidence rate of cervical cancer has decreased over the last several years, low-income ethnic minority women remain at increased risk for morbidity and mortality from cervical cancer. We conducted a pilot study to examine the feasibility and acceptability of mindfulness-based stress reduction (MBSR) program among multiethnic low-income women with abnormal Pap smears. Spanish- and English-speaking women recruited through convenience sampling participated in MBSR classes 2 hours each week over 6 consecutive weeks. State anxiety and self-compassion were measured before and after the MBSR program. Focus groups and surveys were used to evaluate the program. Although 51 women were initially recruited, pre- and post-MBSR data were available only for 8 women. There was a significant reduction in anxiety and a trend toward increased self-compassion in this group of women. The participants evaluated the MBSR program very positively. The high attrition rate highlights the challenges of conducting MBSR research with this demographic of women. Potential strategies for improving recruitment and retention of low-income multiethnic women are discussed.

  9. Evaluation of tributyltin toxicity in Chinese rare minnow larvae by abnormal behavior, energy metabolism and endoplasmic reticulum stress.

    PubMed

    Li, Zhi-Hua; Li, Ping

    2015-02-01

    Tributyltin (TBT) is a ubiquitous contaminant in aquatic environment, but the detailed mechanisms underlying the toxicity of TBT have not been fully understood. In this study, the effects of TBT on behavior, energy metabolism and endoplasmic reticulum (ER) stress were investigated by using Chinese rare minnow larvae. Fish larvae were exposed at sublethal concentrations of TBT (100, 400 and 800 ng/L) for 7 days. Compared with the control, energy metabolic parameters (RNA/DNA ratio, Na(+)-K(+)-ATPase) were significantly inhibited in fish exposed at highest concentration (800 ng/L), as well as abnormal behaviors observed. Moreover, we found that the PERK (PKR-like ER kinase)-eIF2α (eukaryotic translation initiation factor 2α) pathway, as the main branch was activated by TBT exposure in fish larvae. In short, TBT-induced physiological, biochemical and molecular responses in fish larvae were reflected in parameters measured in this study, which suggest that these biomarkers could be used as potential indicators for monitoring organotin compounds present in aquatic environment.

  10. Blockade of corticotropin-releasing hormone receptor 1 attenuates early-life stress-induced synaptic abnormalities in the neonatal hippocampus.

    PubMed

    Liao, Xue-Mei; Yang, Xiao-Dun; Jia, Jiao; Li, Ji-Tao; Xie, Xiao-Meng; Su, Yun-Ai; Schmidt, Mathias V; Si, Tian-Mei; Wang, Xiao-Dong

    2014-05-01

    Adult individuals with early stressful experience exhibit impaired hippocampal neuronal morphology, synaptic plasticity and cognitive performance. While our knowledge on the persistent effects of early-life stress on hippocampal structure and function and the underlying mechanisms has advanced over the recent years, the molecular basis of the immediate postnatal stress effects on hippocampal development remains to be investigated. Here, we reported that repeated blockade of corticotropin-releasing hormone receptor 1 (CRHR1) ameliorated postnatal stress-induced hippocampal synaptic abnormalities in neonatal mice. Following the stress exposure, pups with fragmented maternal care showed retarded dendritic outgrowth and spine formation in CA3 pyramidal neurons and reduced hippocampal levels of synapse-related proteins. During the stress exposure, repeated blockade of glucocorticoid receptors (GRs) by daily administration of RU486 (100 µg g(-1) ) failed to attenuate postnatal stress-evoked synaptic impairments. Conversely, daily administration of the CRHR1 antagonist antalarmin hydrochloride (20 µg g(-1) ) in stressed pups normalized hippocampal protein levels of synaptophysin, postsynaptic density-95, nectin-1, and nectin-3, but not the N-methyl-d-aspartate receptor subunits NR1 and NR2A. Additionally, GR or CRHR1 antagonism attenuated postnatal stress-induced endocrine alterations but not body growth retardation. Our data indicate that the CRH-CRHR1 system modulates the deleterious effects of early-life stress on dendritic development, spinogenesis, and synapse formation, and that early interventions of this system may prevent stress-induced hippocampal maldevelopment.

  11. The Relationship between Personality Dimensions and Resiliency to Environmental Stress in Orange-Winged Amazon Parrots (Amazona amazonica), as Indicated by the Development of Abnormal Behaviors

    PubMed Central

    Cussen, Victoria A.; Mench, Joy A.

    2015-01-01

    Parrots are popular companion animals, but are frequently relinquished because of behavioral problems, including abnormal repetitive behaviors like feather damaging behavior and stereotypy. In addition to contributing to pet relinquishment, these behaviors are important as potential indicators of diminished psychological well-being. While abnormal behaviors are common in captive animals, their presence and/or severity varies between animals of the same species that are experiencing the same environmental conditions. Personality differences could contribute to this observed individual variation, as they are known risk factors for stress sensitivity and affective disorders in humans. The goal of this study was to assess the relationship between personality and the development and severity of abnormal behaviors in captive-bred orange-winged Amazon parrots (Amazona amazonica). We monitored between-individual behavioral differences in enrichment-reared parrots of known personality types before, during, and after enrichment deprivation. We predicted that parrots with higher scores for neurotic-like personality traits would be more susceptible to enrichment deprivation and develop more abnormal behaviors. Our results partially supported this hypothesis, but also showed that distinct personality dimensions were related to different forms of abnormal behavior. While neuroticism-like traits were linked to feather damaging behavior, extraversion-like traits were negatively related to stereotypic behavior. More extraverted birds showed resiliency to environmental stress, developing fewer stereotypies during enrichment deprivation and showing lower levels of these behaviors following re-enrichment. Our data, together with the results of the few studies conducted on other species, suggest that, as in humans, certain personality types render individual animals more susceptible or resilient to environmental stress. Further, this susceptibility/resiliency can have a long

  12. The Relationship between Personality Dimensions and Resiliency to Environmental Stress in Orange-Winged Amazon Parrots (Amazona amazonica), as Indicated by the Development of Abnormal Behaviors.

    PubMed

    Cussen, Victoria A; Mench, Joy A

    2015-01-01

    Parrots are popular companion animals, but are frequently relinquished because of behavioral problems, including abnormal repetitive behaviors like feather damaging behavior and stereotypy. In addition to contributing to pet relinquishment, these behaviors are important as potential indicators of diminished psychological well-being. While abnormal behaviors are common in captive animals, their presence and/or severity varies between animals of the same species that are experiencing the same environmental conditions. Personality differences could contribute to this observed individual variation, as they are known risk factors for stress sensitivity and affective disorders in humans. The goal of this study was to assess the relationship between personality and the development and severity of abnormal behaviors in captive-bred orange-winged Amazon parrots (Amazona amazonica). We monitored between-individual behavioral differences in enrichment-reared parrots of known personality types before, during, and after enrichment deprivation. We predicted that parrots with higher scores for neurotic-like personality traits would be more susceptible to enrichment deprivation and develop more abnormal behaviors. Our results partially supported this hypothesis, but also showed that distinct personality dimensions were related to different forms of abnormal behavior. While neuroticism-like traits were linked to feather damaging behavior, extraversion-like traits were negatively related to stereotypic behavior. More extraverted birds showed resiliency to environmental stress, developing fewer stereotypies during enrichment deprivation and showing lower levels of these behaviors following re-enrichment. Our data, together with the results of the few studies conducted on other species, suggest that, as in humans, certain personality types render individual animals more susceptible or resilient to environmental stress. Further, this susceptibility/resiliency can have a long

  13. 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.

  14. Respiratory arrest during dipyridamole stress testing.

    PubMed Central

    Hillis, G. S.; al-Mohammad, A.; Jennings, K. P.

    1997-01-01

    There is an increasing usage of radionuclide scanning to assess myocardial perfusion, with dipyridamole, the most commonly used stress agent. Although this is an effective, and usually very safe, means by which to assess myocardial blood supply, there have been several incidents of acute bronchospasm in asthmatic patients. There have, however, been no previous reports of respiratory arrest occurring in patients with emphysema. This case illustrates the dangers of administering intravenous dipyridamole, or even adenosine, to patients with chronic lung disease. PMID:9196707

  15. Cold stress and the cold pressor test.

    PubMed

    Silverthorn, Dee U; Michael, Joel

    2013-03-01

    Temperature and other environmental stressors are known to affect blood pressure and heart rate. In this activity, students perform the cold pressor test, demonstrating increased blood pressure during a 1- to 2-min immersion of one hand in ice water. The cold pressor test is used clinically to evaluate autonomic and left ventricular function. This activity is easily adapted to an inquiry format that asks students to go to the scientific literature to learn about the test and then design a protocol for carrying out the test in classmates. The data collected are ideal for teaching graphical presentation of data and statistical analysis.

  16. 12 CFR 46.6 - Stress test methodologies and practices.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... institution under 12 CFR part 3 or part 167, as applicable, and any other capital ratios specified by the OCC... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Stress test methodologies and practices. 46.6 Section 46.6 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY ANNUAL STRESS...

  17. 12 CFR 46.6 - Stress test methodologies and practices.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... institution under 12 CFR part 3 or part 167, as applicable, and any other capital ratios specified by the OCC... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Stress test methodologies and practices. 46.6 Section 46.6 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY ANNUAL STRESS...

  18. Cold Stress and the Cold Pressor Test

    ERIC Educational Resources Information Center

    Silverthorn, Dee U.; Michael, Joel

    2013-01-01

    Temperature and other environmental stressors are known to affect blood pressure and heart rate. In this activity, students perform the cold pressor test, demonstrating increased blood pressure during a 1- to 2-min immersion of one hand in ice water. The cold pressor test is used clinically to evaluate autonomic and left ventricular function. This…

  19. California's Drought - Stress test for the future

    NASA Astrophysics Data System (ADS)

    Lund, J. R.

    2014-12-01

    The current California drought is in its third dry years, with this year being the third driest years in a 106-year record. This drought occurs at a time when urban, agricultural, and environmental water demands have never been greater. This drought has revealed the importance of more quantitative evaluation and methods for water assessment and management. All areas of water and environmental management are likely to become increasingly stressed, and have essentially drought-like conditions, in the future, as California's urban, agricultural, and environmental demands continue to expand and as the climate changes. In the historical past, droughts have pre-viewed stresses developing in the future and helped focus policy-makers, the public, and stakeholders on preparing for these developing future conditions. Multi-decade water management strategies are often galvinized by drought. Irrigation was galvanized by California droughts in the 1800s, reservoir systems by the 1928-32 drought, urban water conservation by the 1976-77 drought, and water markets by the 1988-92 drought. With each drought, demands for tighter accounting, rights, and management have increased. This talk reviews the prospects and challenges for increased development and use of water data and systems analysis in the service of human and environmental water demands in California's highly decentralized water management system, and the prospects if these challenges are not more successfully addressed.

  20. Similar cortical but not subcortical gray matter abnormalities in women with posttraumatic stress disorder with versus without dissociative identity disorder.

    PubMed

    Chalavi, Sima; Vissia, Eline M; Giesen, Mechteld E; Nijenhuis, Ellert R S; Draijer, Nel; Barker, Gareth J; Veltman, Dick J; Reinders, Antje A T S

    2015-03-30

    Neuroanatomical evidence on the relationship between posttraumatic stress disorder (PTSD) and dissociative disorders is still lacking. We acquired brain structural magnetic resonance imaging (MRI) scans from 17 patients with dissociative identity disorder (DID) and co-morbid PTSD (DID-PTSD) and 16 patients with PTSD but without DID (PTSD-only), and 32 healthy controls (HC), and compared their whole-brain cortical and subcortical gray matter (GM) morphological measurements. Associations between GM measurements and severity of dissociative and depersonalization/derealization symptoms or lifetime traumatizing events were evaluated in the patient groups. DID-PTSD and PTSD-only patients, compared with HC, had similarly smaller cortical GM volumes of the whole brain and of frontal, temporal and insular cortices. DID-PTSD patients additionally showed smaller hippocampal and larger pallidum volumes relative to HC, and larger putamen and pallidum volumes relative to PTSD-only. Severity of lifetime traumatizing events and volume of the hippocampus were negatively correlated. Severity of dissociative and depersonalization/derealization symptoms correlated positively with volume of the putamen and pallidum, and negatively with volume of the inferior parietal cortex. Shared abnormal brain structures in DID-PTSD and PTSD-only, small hippocampal volume in DID-PTSD, more severe lifetime traumatizing events in DID-PTSD compared with PTSD-only, and negative correlations between lifetime traumatizing events and hippocampal volume suggest a trauma-related etiology for DID. Our results provide neurobiological evidence for the side-by-side nosological classification of PTSD and DID in the DSM-5. PMID:25670646

  1. Similar cortical but not subcortical gray matter abnormalities in women with posttraumatic stress disorder with versus without dissociative identity disorder.

    PubMed

    Chalavi, Sima; Vissia, Eline M; Giesen, Mechteld E; Nijenhuis, Ellert R S; Draijer, Nel; Barker, Gareth J; Veltman, Dick J; Reinders, Antje A T S

    2015-03-30

    Neuroanatomical evidence on the relationship between posttraumatic stress disorder (PTSD) and dissociative disorders is still lacking. We acquired brain structural magnetic resonance imaging (MRI) scans from 17 patients with dissociative identity disorder (DID) and co-morbid PTSD (DID-PTSD) and 16 patients with PTSD but without DID (PTSD-only), and 32 healthy controls (HC), and compared their whole-brain cortical and subcortical gray matter (GM) morphological measurements. Associations between GM measurements and severity of dissociative and depersonalization/derealization symptoms or lifetime traumatizing events were evaluated in the patient groups. DID-PTSD and PTSD-only patients, compared with HC, had similarly smaller cortical GM volumes of the whole brain and of frontal, temporal and insular cortices. DID-PTSD patients additionally showed smaller hippocampal and larger pallidum volumes relative to HC, and larger putamen and pallidum volumes relative to PTSD-only. Severity of lifetime traumatizing events and volume of the hippocampus were negatively correlated. Severity of dissociative and depersonalization/derealization symptoms correlated positively with volume of the putamen and pallidum, and negatively with volume of the inferior parietal cortex. Shared abnormal brain structures in DID-PTSD and PTSD-only, small hippocampal volume in DID-PTSD, more severe lifetime traumatizing events in DID-PTSD compared with PTSD-only, and negative correlations between lifetime traumatizing events and hippocampal volume suggest a trauma-related etiology for DID. Our results provide neurobiological evidence for the side-by-side nosological classification of PTSD and DID in the DSM-5.

  2. [Stress-corrosion test of TIG welded CP-Ti].

    PubMed

    Li, H; Wang, Y; Zhou, Z; Meng, X; Liang, Q; Zhang, X; Zhao, Y

    2000-12-01

    In this study TIG (Tungsten Inert Gas) welded CP-Ti were subjected to stress-corrosion test under 261 MPa in artificial saliva of 37 degrees C for 3 months. No significant difference was noted on mechanical test (P > 0.05). No color-changed and no micro-crack on the sample's surface yet. These results indicate that TIG welded CP-Ti offers excellent resistance to stress corrosion. PMID:11211846

  3. A Methodology to Detect Abnormal Relative Wall Shear Stress on the Full Surface of the Thoracic Aorta Using 4D Flow MRI

    PubMed Central

    van Ooij, Pim; Potters, Wouter V.; Nederveen, Aart J.; Allen, Bradley D.; Collins, Jeremy; Carr, James; Malaisrie, S. Chris; Markl, Michael; Barker, Alex J.

    2014-01-01

    Purpose To compute cohort-averaged wall shear stress (WSS) maps in the thoracic aorta of patients with aortic dilatation or valvular stenosis and to detect abnormal regional WSS. Methods Systolic WSS vectors, estimated from 4D flow MRI data, were calculated along the thoracic aorta lumen in 10 controls, 10 patients with dilated aortas and 10 patients with aortic valve stenosis. 3D segmentations of each aorta were co-registered by group and used to create a cohort-specific aortic geometry. The WSS vectors of each subject were interpolated onto the corresponding cohort-specific geometry to create cohort-averaged WSS maps. A Wilcoxon rank sum test was used to generate aortic P-value maps (P<0.05) representing regional relative WSS differences between groups. Results Cohort-averaged systolic WSS maps and P-value maps were successfully created for all cohorts and comparisons. The dilation cohort showed significantly lower WSS on 7% of the ascending aorta surface, whereas the stenosis cohort showed significantly higher WSS aorta on 34% the ascending aorta surface. Conclusions The findings of this study demonstrated the feasibility of generating cohort-averaged WSS maps for the visualization and identification of regionally altered WSS in the presence of disease, as compared to healthy controls. PMID:24753241

  4. A rabbit ear model for cold stress testing.

    PubMed

    Smith, T L; Gordon, S; Holden, M B; Smith, B P; Russell, G B; Koman, L A

    1994-01-01

    A rabbit ear model resembling the human digit was studied to determine the vascular response of the rabbit ear to a cold stress. Following moderate cooling (10 minutes at 5 degrees - 8 degrees C), auricular blood flow and cutaneous perfusion were reduced. This decrease was reversed by 30 minutes of warming. The response in the rabbit ear to cold stress is similar to that of normal human digits. The similarities between the control of the circulation in human digits and rabbit ears may result from the similarities in digital and auricular vascular receptors and receptor subtypes. Verification of the rabbit model provides an experimental method for obtaining important data regarding digital pathophysiology and the treatment of cold intolerance. Further study with this model will provide clinically relevant information regarding the pathophysiology of digital thermoregulatory abnormalities. PMID:7830538

  5. Peripuberty stress leads to abnormal aggression, altered amygdala and orbitofrontal reactivity and increased prefrontal MAOA gene expression

    PubMed Central

    Márquez, C; Poirier, G L; Cordero, M I; Larsen, M H; Groner, A; Marquis, J; Magistretti, P J; Trono, D; Sandi, C

    2013-01-01

    Although adverse early life experiences have been found to increase lifetime risk to develop violent behaviors, the neurobiological mechanisms underlying these long-term effects remain unclear. We present a novel animal model for pathological aggression induced by peripubertal exposure to stress with face, construct and predictive validity. We show that male rats submitted to fear-induction experiences during the peripubertal period exhibit high and sustained rates of increased aggression at adulthood, even against unthreatening individuals, and increased testosterone/corticosterone ratio. They also exhibit hyperactivity in the amygdala under both basal conditions (evaluated by 2-deoxy-glucose autoradiography) and after a resident–intruder (RI) test (evaluated by c-Fos immunohistochemistry), and hypoactivation of the medial orbitofrontal (MO) cortex after the social challenge. Alterations in the connectivity between the orbitofrontal cortex and the amygdala were linked to the aggressive phenotype. Increased and sustained expression levels of the monoamine oxidase A (MAOA) gene were found in the prefrontal cortex but not in the amygdala of peripubertally stressed animals. They were accompanied by increased activatory acetylation of histone H3, but not H4, at the promoter of the MAOA gene. Treatment with an MAOA inhibitor during adulthood reversed the peripuberty stress-induced antisocial behaviors. Beyond the characterization and validation of the model, we present novel data highlighting changes in the serotonergic system in the prefrontal cortex—and pointing at epigenetic control of the MAOA gene—in the establishment of the link between peripubertal stress and later pathological aggression. Our data emphasize the impact of biological factors triggered by peripubertal adverse experiences on the emergence of violent behaviors. PMID:23321813

  6. Composite Overwrapped Pressure Vessel(COPV) Stress Rupture Testing

    NASA Astrophysics Data System (ADS)

    Greene, Nathanael J.; Saulsberry, Regor L.; Leifeste, Mark, R.; Yoder, Tommy B.; Keddy, Chris P.; Forth, Scott C.; Russell, Rick W.

    2010-09-01

    This paper reports stress rupture testing of Kevlar® composite overwrapped pressure vessels(COPVs) at NASA White Sands Test Facility. This 6-year test program was part of the larger effort to predict and extend the lifetime of flight vessels. Tests were performed to characterize control parameters for stress rupture testing, and vessel life was predicted by statistical modeling. One highly instrumented 102-cm(40-in.) diameter Kevlar® COPV was tested to failure(burst) as a single-point model verification. Significant data were generated that will enhance development of improved NDE methods and predictive modeling techniques, and thus better address stress rupture and other composite durability concerns that affect pressure vessel safety, reliability and mission assurance.

  7. Composite Overwrapped Pressure Vessel (COPV) Stress Rupture Testing

    NASA Technical Reports Server (NTRS)

    Greene, Nathanael J.; Saulsberry, Regor L.; Leifeste, Mark R.; Yoder, Tommy B.; Keddy, Chris P.; Forth, Scott C.; Russell, Rick W.

    2010-01-01

    This paper reports stress rupture testing of Kevlar(TradeMark) composite overwrapped pressure vessels (COPVs) at NASA White Sands Test Facility. This 6-year test program was part of the larger effort to predict and extend the lifetime of flight vessels. Tests were performed to characterize control parameters for stress rupture testing, and vessel life was predicted by statistical modeling. One highly instrumented 102-cm (40-in.) diameter Kevlar(TradeMark) COPV was tested to failure (burst) as a single-point model verification. Significant data were generated that will enhance development of improved NDE methods and predictive modeling techniques, and thus better address stress rupture and other composite durability concerns that affect pressure vessel safety, reliability and mission assurance.

  8. A Theory-Based Approach to Understanding Follow-up of Abnormal Pap Tests

    PubMed Central

    Breitkopf, Carmen Radecki; Pearson, Heidi C.

    2009-01-01

    We applied a general theoretical framework to understand intentions to attend recommended follow-up for abnormal Pap results. Participants were 338 women attending university-affiliated clinics. Intention was associated with favorable attitudes toward follow-up (OR=5.3); perceiving attending follow-up as consistent with one’s self-concept (OR=3.0); self-efficacy (OR=1.8); and believing one would be told exactly what is wrong (OR=1.3). Intention was negatively associated with believing the problem could be avoided by not returning for follow-up (OR=0.75). Beliefs, affect and attitudes differed by race and ethnicity (all p<0.05). Attendance at follow-up was related to attitude and self-concept (both p<0.05). Results have implications for theory development and patient education. PMID:19293297

  9. Application of silicon piezoresistive stress test chips in electronic packages

    NASA Astrophysics Data System (ADS)

    Zou, Yida

    In this work, both special (100) and (111) silicon test chips containing an array of optimized piezoresistive stress sensor rosettes have been successfully applied within several electronic packaging configurations. Unlike (100) silicon test chips, (111) silicon test chips are able to measure the complete stress state on the die surface. After calibration and characterization of the test chips, they were packaged into various assemblies. The post packaging resistances of the sensors were then recorded at room temperature, as a function of temperature excursion, and during long term packaging reliability qualification tests (thermal cycling and thermal aging). The stresses on the die surface were calculated using the measured resistance changes and the appropriate theoretical equations. For comparison purposes, three-dimensional nonlinear finite element simulations of the packaging processes were also performed, and the stress predictions were correlated with the experimental test chip data. AAA2 (100) silicon test chips containing optimized four element dual polarity rosettes have been applied within 44 pin Plastic Leaded Chip Carrier (PLCC) packages and 240 pin Quad Flat Packs (QFP's). In these plastic package experiments, comparison of the stress levels induced by various molding compounds was emphasized. Advanced (111) silicon test chips (BMW-1 or BMW-2) comprising an array of optimized eight-element dual polarity piezoresistive sensor rosettes were encapsulated in 240 pin QFP's, 160 pin QFP's, Chip on Board (COB) packages, and 281 pin ceramic Pin Grid Array (PGA) packages. In addition to molding compound evaluations, BMW-1 test chips encapsulated in 240 pin QFP's were used to detect the presence of delaminations between the die surface and the encapsulant. In the wire bonded COB package studies, die surface stress evaluations were conducted after die attachment, and throughout the cure cycle of the liquid encapsulant. The stresses were also studied as a

  10. Liver Function Test Abnormalities in Depressed Patients Treated with Antidepressants: A Real-World Systematic Observational Study in Psychiatric Settings

    PubMed Central

    Verstuyft, Céline; Corruble, Emmanuelle; Perlemuter, Gabriel; Colle, Romain

    2016-01-01

    Background Concerning the risk of antidepressant induced liver injury, it is not clear whether psychiatrists perform a liver function test (LFT) and whether an increase in aminotransferase levels should contraindicate antidepressant treatment. Aim To evaluate LFT availability, the prevalence of LFT abnormalities and the probable cause of an altered LFT in patients with a major depressive episode (MDE) requiring an antidepressant drug. Methods We studied LFT evaluation in a real world psychiatric setting, in a sample of 321 consecutive patients with a current major depressive episode (MDE) requiring an antidepressant drug treatment, but without current alcohol or drug dependence or unstable medical disease. Results An LFT is performed in 36.1% (116/321) of depressed patients. One fifth of antidepressant-treated patients who had an LFT evaluation had abnormal results. The most frequent causes of LFT abnormalities were: NAFLD (nonalcoholic fatty liver disease) (7/321; 2.1%), acute alcohol consumption (4/321; 1.2%), antidepressant-induced liver injury (3/321; 0.9%), hepatitis C virus infection (2/321; 0.6%) and heart failure (1/321; 0.3%). The cause of LFT abnormalities was unknown in 32% of patients (8/25) due to the absence of etiological investigations. Conclusion These results demonstrate that an LFT is infrequently performed by psychiatrists in depressed patients requiring an antidepressant drug. Baseline LFT assessment and observations during the first six months of antidepressant treatment may be useful for detection of patients with pre-existing liver disease such as NAFLD, and early identification of cases of antidepressant-induced liver injury. An increase in aminotransferase levels may be related to an underlying liver disease, but does not contraindicate antidepressant treatment. PMID:27171561

  11. Respiratory symptoms in rheumatoid arthritis: relation to pulmonary abnormalities detected by high-resolution CT and pulmonary functional testing.

    PubMed

    Youssef, Amir A; Machaly, Shereen A; El-Dosoky, Mohammed E; El-Maghraby, Nermeen M

    2012-07-01

    Pulmonary disease is the most frequent and among the most severe extra-articular manifestation of rheumatoid arthritis (RA). However, this issue has not been sufficiently studied in Egyptian patients. The objectives of the present study are to investigate the prevalence and types of pulmonary involvement using high-resolution computed tomography scan (HRCT) and pulmonary function tests (PFT) and evaluate the association between respiratory symptoms and RA-lung disease in a group of Egyptian RA patients. Thirty-six RA patients were recruited; 34 females (94.4%) and 2 males (5.6%) with median age of 48.5 years, and none of them was smoker. Detailed medical and drug histories were obtained. PFT, plain X-ray of the chest, and HRCT were performed to all subjects involved. Nearly 64% of RA patients demonstrated abnormalities in PFT and 47% in HRCT. Mixed restrictive and obstructive pattern was the commonest. Nearly two-thirds of our patients reported one or more pulmonary symptom whether dyspnea, cough, wheezing, or phlegm. Dyspnea was the most frequent symptom. Respiratory symptoms were statistically more common in patients with lung disease. The advanced age, high radiological score, and severity of rheumatoid disease were found to be predictive of lung involvement. Among respiratory symptoms, dyspnea and cough were associated with any pulmonary abnormalities. When specific pulmonary abnormalities were considered, only dyspnea was identified as predictor for restriction. For obstructive abnormality, both cough and wheezing provided valid prediction. We conclude that pulmonary involvement is a common manifestation in Egyptian RA patients, and the pattern of involvement is generally consistent with other studies that were performed worldwide. Specific respiratory symptoms could be used as practical, easy, and cost-effective method, especially in older and with more severe RA patients, to discriminate patients in need of subsequent PFT and HRCT imaging.

  12. 77 FR 62417 - Annual Stress Test

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-15

    ... NPR, with certain modifications as described further below. \\3\\ 77 FR 3166 (Jan. 23, 2012). II... necessary to conduct these tests. E. Scenario Development A number of the comments received by the... discussed further below. \\4\\ 77 FR 52718 (Aug. 30, 2012). The FDIC reserves the authority to require a...

  13. Diagnostic errors and abnormal diagnostic tests lost to follow-up: a source of needless waste and delay to treatment.

    PubMed

    Wahls, Terry

    2007-01-01

    Diagnostic errors are an important and often underappreciated source of medical error, needless delays to treatment, and needlessly wasted resources. Almost 65% of diagnostic errors have an important contribution of system errors, of which many are an abnormal test result that was lost to follow-up, that is, missed results. These system problems that contribute to missed results may represent low-hanging fruit for those who wish to reduce diagnostic errors in their institution. The rate of missed results and associated treatment delay are discussed. The system factors and human factors that contribute to these errors are discussed along with strategies that can be adopted to reduce these errors. PMID:17873665

  14. Optimal design of multiple stress constant accelerated life test plan on non-rectangle test region

    NASA Astrophysics Data System (ADS)

    Chen, Wenhua; Gao, Liang; Liu, Juan; Qian, Ping; Pan, Jun

    2012-11-01

    For optimal design of constant stress accelerated life test(CSALT) with two-stress, if the stresses could not reach the highest levels simultaneously, the test region becomes non-rectangular. For optimal CSALT design on non-rectangle test region, the present method is only focused on non-rectangle test region with simple boundary, and the optimization algorithm is based on experience which can not ensure to obtain the optimal plan. In this paper, considering the linear-extreme value model and the optimization goal to minimize the variance of lifetime estimate under normal stress, the optimal design method of two-stress type-I censored CSALT plan on general non-rectangular test region is proposed. First, two properties of optimal test plans are proved and the relationship of all the optimal test plans is determined analytically. Then, on the basis of the two properties, the optimal problem is simplified and the optimal design method of two-stress CSALT plan on general non-rectangular test region is proposed. Finally, a numerical example is used to illustrate the feasibility and effectiveness of the method. The result shows that the proposed method could obtain the optimal test plan on non-rectangular test regions with arbitrary boundaries. This research provides the theory and method for two-stress optimal CSALT planning on non-rectangular test regions.

  15. Testing the facilitation–competition paradigm under the stress-gradient hypothesis: decoupling multiple stress factors

    PubMed Central

    Kawai, Takashi; Tokeshi, Mutsunori

    2007-01-01

    While the facilitation–competition paradigm under the stress-gradient hypothesis has received recent attention, its rigorous testing is yet to be explored. Most of the studies have considered a switch in the net interactions from competition to facilitation with increasing environmental stress as primary evidence supporting the hypothesis, though few studies examined changes in interaction along a full range of a stress gradient. Here, we have conceptualized possible variations in the patterns of change in interaction strength along such gradient. Based on this, we empirically evaluated the temporal shift in the interaction between two marine sessile animals, goose barnacles (Capitulum mitella) and mussels (Septifer virgatus), under multiple stress factors. The net effect of goose barnacles on mussel survivorship was positively related to the total stress gradient encompassing two stress factors, physical disturbance and thermal stress, while no negative value occurred even under mild conditions. When the two stress factors were treated separately, however, the net effect demonstrated apparently different patterns: monotonic increase with physical disturbance versus a quasi-asymptotic pattern (no change over a wide range) with thermal stress. These variable situations have not previously been recognized in this discipline, and the present study emphasizes the importance of an integrative and mechanistic approach to testing and deciphering the facilitation–competition paradigm. PMID:17686725

  16. Testing the facilitation-competition paradigm under the stress-gradient hypothesis: decoupling multiple stress factors.

    PubMed

    Kawai, Takashi; Tokeshi, Mutsunori

    2007-10-01

    While the facilitation-competition paradigm under the stress-gradient hypothesis has received recent attention, its rigorous testing is yet to be explored. Most of the studies have considered a switch in the net interactions from competition to facilitation with increasing environmental stress as primary evidence supporting the hypothesis, though few studies examined changes in interaction along a full range of a stress gradient. Here, we have conceptualized possible variations in the patterns of change in interaction strength along such gradient. Based on this, we empirically evaluated the temporal shift in the interaction between two marine sessile animals, goose barnacles (Capitulum mitella) and mussels (Septifer virgatus), under multiple stress factors. The net effect of goose barnacles on mussel survivorship was positively related to the total stress gradient encompassing two stress factors, physical disturbance and thermal stress, while no negative value occurred even under mild conditions. When the two stress factors were treated separately, however, the net effect demonstrated apparently different patterns: monotonic increase with physical disturbance versus a quasi-asymptotic pattern (no change over a wide range) with thermal stress. These variable situations have not previously been recognized in this discipline, and the present study emphasizes the importance of an integrative and mechanistic approach to testing and deciphering the facilitation-competition paradigm.

  17. An improved stress corrosion test medium for aluminum alloys

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Coston, J. E.

    1981-01-01

    A laboratory test method that is only mildly corrosive to aluminum and discriminating for use in classifying the stress corrosion cracking resistance of aluminum alloys is presented along with the method used in evaluating the media selected for testing. The proposed medium is easier to prepare and less expensive than substitute ocean water.

  18. Predictive Accuracy of Exercise Stress Testing the Healthy Adult.

    ERIC Educational Resources Information Center

    Lamont, Linda S.

    1981-01-01

    Exercise stress testing provides information on the aerobic capacity, heart rate, and blood pressure responses to graded exercises of a healthy adult. The reliability of exercise tests as a diagnostic procedure is discussed in relation to sensitivity and specificity and predictive accuracy. (JN)

  19. 12 CFR 252.154 - Annual stress test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... test required by this section. The Board may also require a state member bank that is subject to 12 CFR...)(i) or 12 CFR 252.144(b)(2)(i) to include a trading and counterparty component in the state member... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Annual stress test. 252.154 Section...

  20. 77 FR 62377 - Supervisory and Company-Run Stress Test Requirements for Covered Companies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-12

    ... Companies, 77 FR 594 (Jan. 5, 2012). Together, the supervisory stress tests and the company-run stress tests... on proposed rules in January of 2012.\\12\\ \\12\\ Annual Stress Test, 77 FR 3408 (Jan. 24, 2012) (OCC); Annual Stress Test, 77 FR 3166 (Jan. 17, 2012) (FDIC). The Board is finalizing the stress...

  1. Effects of test stress during an objective structured clinical examination

    PubMed Central

    Zhang, Niu; Rabatsky, Ali

    2015-01-01

    Objective The existence of test stress has been widely reported among professional students. To our knowledge, no studies exist that explore student stress response to objective structured clinical examinations. The aim of this study was to evaluate possible correlations between stress and objective structured clinical examination performance in a sample of chiropractic students. Methods A total of 116 students completed a 2-part questionnaire to assess test stress and the physiological symptoms and signs of stress. Heart rate, systolic blood pressure, and diastolic were measured during the physical examination laboratory class within the first 3 weeks and then again just prior to their objective structured clinical examination in week 5. Statistical tests were then performed for questionnaire data, heart rate and blood pressure differences, and correlation between the objective structured clinical examination grade and symptoms and signs. Results Questionnaire results showed that 5.1%–22.4% of students sometimes or often felt a certain degree of stress. More than 50% had 1 or more physiological symptoms and signs of stress. The objective structured clinical examination heart rate (75.23 ± 11.20 vs 68.16 ± 8.82, p < .001), systolic blood pressure (120.43 ± 9.59 vs 114.97 ± 11.83, p < .001), and diastolic blood pressure (73.00 ± 7.93 vs 69.32 ± 7.76, p < .001) were significantly higher than baseline. There were also negative linear correlations between objective structured clinical examination grades and physiological symptoms and signs and between objective structured clinical examination grades and feeling statement score. Conclusion The results support our hypothesis that chiropractic students experience stress when performing the objective structured clinical examination and that high levels of stress had a negative impact on performance. PMID:25806413

  2. Dynamic testing of hypothalamic-pituitary function in abnormalities of ovulation.

    PubMed

    Jones, G E; Wentz, A C; Rosenwaks, Z; Shoemaker, J

    1977-12-01

    A review of 26 unusual patients indicates that a combined luteinizing hormone-releasing hormone (LRH)-clomiphene test in conjunction with an estrogen provocation test not only was helpful in identifying underlying pathophysiology of anovulation but also proved useful in the clinical management of the patients. Dynamic testing per se does not establish a diagnosis but, in conjunction with history and other laboratory findings, it does make possible further subdivisions of groups of patients who otherwise appear similar, both clinically and from routine laboratory evaluations. It, therefore, tends to pinpoint a lesion and establish the area in which further tests should be made. It is concluded that the value of such investigations will be more evident as gynecologic endocrinology moves into investigation of the supratentorial control of hypothalamic function and as hypothalamic LRH becomes available as a therapeutic agent.

  3. Abnormal response to stress and impaired NPS-induced hyperlocomotion, anxiolytic effect and corticosterone increase in mice lacking NPSR1

    PubMed Central

    Zhu, Hongyan; Mingler, Melissa K.; McBride, Melissa L.; Murphy, Andrew J.; Valenzuela, David M.; Yancopoulos, George D.; Williams, Michael T.; Vorhees, Charles V.; Rothenberg, Marc E.

    2010-01-01

    Summary NPSR1 is a G protein coupled receptor expressed in multiple brain regions involved in modulation of stress. Central administration of NPS, the putative endogenous ligand of NPSR1, can induce hyperlocomotion, anxiolytic effects and activation of the HPA axis. The role of NPSR1 in the brain remains unsettled. Here we used NPSR1 gene-targeted mice to define the functional role of NPSR1 under basal conditions on locomotion, anxiety- and/or depression-like behavior, corticosterone levels, acoustic startle with prepulse inhibition, learning and memory, and under NPS-induced locomotor activation, anxiolysis, and corticosterone release. Male, but not female, NPSR1-deficient mice exhibited enhanced depression-like behavior in a forced swim test, reduced acoustic startle response, and minor changes in the Morris water maze. Neither male nor female NPSR1-deficient mice showed alterations of baseline locomotion, anxiety-like behavior, or corticosterone release after exposure to a forced swim test or methamphetamine challenge in an open-field. After intracerebroventricular (ICV) administration of NPS, NPSR1-deficient mice failed to show normal NPS-induced increases in locomotion, anxiolysis, or corticosterone release compared with WT NPS-treated mice. These findings demonstrate that NPSR1 is essential in mediating NPS effects on behavior. PMID:20171785

  4. Abnormal response to stress and impaired NPS-induced hyperlocomotion, anxiolytic effect and corticosterone increase in mice lacking NPSR1.

    PubMed

    Zhu, Hongyan; Mingler, Melissa K; McBride, Melissa L; Murphy, Andrew J; Valenzuela, David M; Yancopoulos, George D; Williams, Michael T; Vorhees, Charles V; Rothenberg, Marc E

    2010-09-01

    NPSR1 is a G protein coupled receptor expressed in multiple brain regions involved in modulation of stress. Central administration of NPS, the putative endogenous ligand of NPSR1, can induce hyperlocomotion, anxiolytic effects and activation of the HPA axis. The role of NPSR1 in the brain remains unsettled. Here we used NPSR1 gene-targeted mice to define the functional role of NPSR1 under basal conditions on locomotion, anxiety- and/or depression-like behavior, corticosterone levels, acoustic startle with prepulse inhibition, learning and memory, and under NPS-induced locomotor activation, anxiolysis, and corticosterone release. Male, but not female, NPSR1-deficient mice exhibited enhanced depression-like behavior in a forced swim test, reduced acoustic startle response, and minor changes in the Morris water maze. Neither male nor female NPSR1-deficient mice showed alterations of baseline locomotion, anxiety-like behavior, or corticosterone release after exposure to a forced swim test or methamphetamine challenge in an open-field. After intracerebroventricular (ICV) administration of NPS, NPSR1-deficient mice failed to show normal NPS-induced increases in locomotion, anxiolysis, or corticosterone release compared with WT NPS-treated mice. These findings demonstrate that NPSR1 is essential in mediating NPS effects on behavior.

  5. Stress-induced antibiotic susceptibility testing on a chip.

    PubMed

    Kalashnikov, Maxim; Campbell, Jennifer; Lee, Jean C; Sharon, Andre; Sauer-Budge, Alexis F

    2014-01-08

    We have developed a rapid microfluidic method for antibiotic susceptibility testing in a stress-based environment. Fluid is passed at high speeds over bacteria immobilized on the bottom of a microfluidic channel. In the presence of stress and antibiotic, susceptible strains of bacteria die rapidly. However, resistant bacteria survive these stressful conditions. The hypothesis behind this method is new: stress activation of biochemical pathways, which are targets of antibiotics, can accelerate antibiotic susceptibility testing. As compared to standard antibiotic susceptibility testing methods, the rate-limiting step - bacterial growth - is omitted during antibiotic application. The technical implementation of the method is in a combination of standard techniques and innovative approaches. The standard parts of the method include bacterial culture protocols, defining microfluidic channels in polydimethylsiloxane (PDMS), cell viability monitoring with fluorescence, and batch image processing for bacteria counting. Innovative parts of the method are in the use of culture media flow for mechanical stress application, use of enzymes to damage but not kill the bacteria, and use of microarray substrates for bacterial attachment. The developed platform can be used in antibiotic and nonantibiotic related drug development and testing. As compared to the standard bacterial suspension experiments, the effect of the drug can be turned on and off repeatedly over controlled time periods. Repetitive observation of the same bacterial population is possible over the course of the same experiment.

  6. Elimination of Potential Electrical Stress During EMC (CS01) Testing

    NASA Technical Reports Server (NTRS)

    Erickson, Kenneth P.; Whittlesey, Albert C.; Vorperian, Vatche

    2006-01-01

    This viewgraph presentation reviews possible ways to eliminate electrical stress during Electromagneticic Compatibility (EMC) testing. The presentation reviews tests that have had problems due to electrical stress. On December 5, 1995 Cassini Radar instrument failed a functional test in preparation for EMC conducted susceptibility (CSO 1 ) testing. The instrument power supply did not turn on as required, and failure occurred prior to injection of CS test stimulus. A investigation of the failure was conducted. A PSPICE simulation of Cassini Radar 30V line using the EMC test setup was performed; the result of the simulation was an oscillation on the 30V input of the power supply. In another case: on December 28, 1999 an oscillation occurred on the input power line of the SlRTF Infrared Array Camera (IRAC) while preparing to perform CSOI testing, Resulted in damage to flight hardware. Subsequent to failure, JPL provided GSFC history and corrective action from Cassini Radar CSOI test failure GSFC implemented the same corrective action as JPL, except that the value of the resistor connected across the isolation transformer primary winding is 2.5 ohms instead of 50 ohms. Three recommendations are made: (1) Make EMC test community aware of the problem and potential solutions by presenting papers at major environmental test conferences (2) Include warnings and safeguards in EMC test requirements and procedures (3) Try to convince EMC test equipment suppliers to design a CSOl test fixture similar to fixture shown in the diagram

  7. Cannabinoids & Stress: impact of HU-210 on behavioral tests of anxiety in acutely stressed mice.

    PubMed

    Kinden, Renee; Zhang, Xia

    2015-05-01

    Anxiety disorders are one of the most prevalent classes of mental disorders affecting the general population, but current treatment strategies are restricted by their limited efficacy and side effect profiles. Although the cannabinoid system is speculated to be a key player in the modulation of stress responses and emotionality, the vast majority of current research initiatives had not incorporated stress exposure into their experimental designs. This study was the first to investigate the impact of exogenous cannabinoid administration in an acutely stressed mouse model, where CD1 mice were pre-treated with HU-210, a potent CB1R agonist, prior to acute stress exposure and subsequent behavioral testing. Exogenous cannabinoid administration induced distinct behavioral phenotypes in stressed and unstressed mice. While low doses of HU-210 were anxiolytic in unstressed subjects, this effect was abolished when mice were exposed to an acute stressor. The administration of higher HU-210 doses in combination with acute stress exposure led to severe locomotor deficits that were not previously observed at the same dose in unstressed subjects. These findings suggest that exogenous cannabinoids and acute stress act synergistically in an anxiogenic manner. This study underlies the importance of including stress exposure into future anxiety-cannabinoid research due to the differential impact of cannabinoid administration on stressed and unstressed subjects.

  8. Screening for chromosomal abnormalities using combined test in the first trimester of pregnancy

    PubMed Central

    Park, Soo Yeon; Jang, In Ae; Lee, Min Ah; Kim, Young Ju; Chun, Sun Hee

    2016-01-01

    Objective This study was designed to review the screening performance of combined test at the Ewha Womans University Mokdong hospital. Methods All women admitted for routine antenatal care between January 1st 2008 and December 31st 2012 with a known pregnancy outcome were included in this study, totaling 1,156 women with singleton pregnancies presenting at 10 to 13 weeks of gestation. Women were offered screening using a combination of maternal serum pregnancy-associated plasma protein-A, free β-human chorionic gonadotropin and fetal nuchal translucency thickness. Those with an estimated risk of ≥1 in 250 of carrying a fetus with trisomy 21 or ≥1 in 300 risk of trisomy 18 were offered genetic counseling with the option of an invasive diagnostic test. Results The median of gestational age was 11+3 weeks, the median of crown-rump length was 47.1 mm, and the median age of the women was 31 years. The detection rate was 80% for trisomy 21 (4 of 5) and 100% for trisomy 13 and 18 (all 2). The false-positive rate was 7.73% for trisomy 21 and 1.21% for trisomy 18. Conclusion This study was the first large population study performed with the aim of analyzing the performance of the combined test in Korea. This study demonstrated that the detection rates and other figures of the first trimester combined test are comparable to the results reported in other papers worldwide. Consequently, if strict conditions for good screening outcomes are achieved, the first trimester combined test might well be the earliest detectable screening, improving detection rates without increasing karyotyping or economic and other implications that inevitably ensue. PMID:27668198

  9. Screening for chromosomal abnormalities using combined test in the first trimester of pregnancy

    PubMed Central

    Park, Soo Yeon; Jang, In Ae; Lee, Min Ah; Kim, Young Ju; Chun, Sun Hee

    2016-01-01

    Objective This study was designed to review the screening performance of combined test at the Ewha Womans University Mokdong hospital. Methods All women admitted for routine antenatal care between January 1st 2008 and December 31st 2012 with a known pregnancy outcome were included in this study, totaling 1,156 women with singleton pregnancies presenting at 10 to 13 weeks of gestation. Women were offered screening using a combination of maternal serum pregnancy-associated plasma protein-A, free β-human chorionic gonadotropin and fetal nuchal translucency thickness. Those with an estimated risk of ≥1 in 250 of carrying a fetus with trisomy 21 or ≥1 in 300 risk of trisomy 18 were offered genetic counseling with the option of an invasive diagnostic test. Results The median of gestational age was 11+3 weeks, the median of crown-rump length was 47.1 mm, and the median age of the women was 31 years. The detection rate was 80% for trisomy 21 (4 of 5) and 100% for trisomy 13 and 18 (all 2). The false-positive rate was 7.73% for trisomy 21 and 1.21% for trisomy 18. Conclusion This study was the first large population study performed with the aim of analyzing the performance of the combined test in Korea. This study demonstrated that the detection rates and other figures of the first trimester combined test are comparable to the results reported in other papers worldwide. Consequently, if strict conditions for good screening outcomes are achieved, the first trimester combined test might well be the earliest detectable screening, improving detection rates without increasing karyotyping or economic and other implications that inevitably ensue.

  10. A test of stress theory: relief workers in refugee camps.

    PubMed

    Soliman, Hussein H; Gillespie, David F

    2011-10-01

    The purpose of this paper is to apply a stress model drawn from the literature to the relief and social service workers who have been active in refugee camps for a prolonged period of time. Working in difficult environments, social service workers deliver essential services to refugee populations around the world. A model of four work-stress determinants--tasks, management, appreciation and collaboration--was tested on 274 social workers in five regions of the Middle East (Jordan, Lebanon and Syria, as well as the occupied Palestinian territories of the Gaza Strip and the West Bank). Statistical fit indices were adequate but two relationships were statistically insignificant. The collaboration variable was dropped to create a modified model with tasks indirectly and management and appreciation directly affecting work-related stress. The five direct relationships and two indirect relationships of this modified model are consistent with stress theory, and all relationships--direct and indirect--are statistically significant.

  11. Stress during a Critical Postnatal Period Induces Region-Specific Structural Abnormalities and Dysfunction of the Prefrontal Cortex via CRF1

    PubMed Central

    Yang, Xiao-Dun; Liao, Xue-Mei; Uribe-Mariño, Andrés; Liu, Rui; Xie, Xiao-Meng; Jia, Jiao; Su, Yun-Ai; Li, Ji-Tao; Schmidt, Mathias V; Wang, Xiao-Dong; Si, Tian-Mei

    2015-01-01

    During the early postnatal period, environmental influences play a pivotal role in shaping the development of the neocortex, including the prefrontal cortex (PFC) that is crucial for working memory and goal-directed actions. Exposure to stressful experiences during this critical period may disrupt the development of PFC pyramidal neurons and impair the wiring and function of related neural circuits. However, the molecular mechanisms of the impact of early-life stress on PFC development and function are not well understood. In this study, we found that repeated stress exposure during the first postnatal week hampered dendritic development in layers II/III and V pyramidal neurons in the dorsal agranular cingulate cortex (ACd) and prelimbic cortex (PL) of neonatal mice. The deleterious effects of early postnatal stress on structural plasticity persisted to adulthood only in ACd layer V pyramidal neurons. Most importantly, concurrent blockade of corticotropin-releasing factor receptor 1 (CRF1) by systemic antalarmin administration (20 μg/g of body weight) during early-life stress exposure prevented stress-induced apical dendritic retraction and spine loss in ACd layer V neurons and impairments in PFC-dependent cognitive tasks. Moreover, the magnitude of dendritic regression, especially the shrinkage of apical branches, of ACd layer V neurons predicted the degree of cognitive deficits in stressed mice. Our data highlight the region-specific effects of early postnatal stress on the structural plasticity of prefrontal pyramidal neurons, and suggest a critical role of CRF1 in modulating early-life stress-induced prefrontal abnormalities. PMID:25403725

  12. Partial shade stress test for thin-film photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Silverman, Timothy J.; Deceglie, Michael G.; Deline, Chris; Kurtz, Sarah

    2015-09-01

    Partial shade of monolithic thin-film PV modules can cause reverse-bias conditions leading to permanent damage. In this work, we introduce a partial shade stress test for thin-film PV modules that quantifies permanent performance loss. The test reproduces shading and loading conditions that may occur in the field. It accounts for reversible light-induced performance changes and for the effects of light-enhanced reverse breakdown. We simulated the test procedure using a computer model that predicts the local voltage, current and temperature stress resulting from partial shade. We also performed the test on three commercial module types. Each module type we tested suffered permanent damage during masked ash testing totaling < 2 s of light exposure. During the subsequent stress test these module types lost 4%{11% in Pmp due to widespread formation of new shunts. One module type showed a substantial worsening of the Pmp loss upon light stabilization, underscoring the importance of this practice for proper quantification of damage.

  13. Avian Test Battery for the Evaluation of Developmental Abnormalities of Neuro- and Reproductive Systems.

    PubMed

    Kawashima, Takaharu; Ahmed, Walaa M S; Nagino, Koki; Ubuka, Takayoshi; Tsutsui, Kazuyoshi

    2016-01-01

    Most of the currently used toxicity assays for environmental chemicals use acute or chronic systemic or reproductive toxicity endpoints rather than neurobehavioral endpoints. In addition, the current standard approaches to assess reproductive toxicity are time-consuming. Therefore, with increasing numbers of chemicals being developed with potentially harmful neurobehavioral effects in higher vertebrates, including humans, more efficient means of assessing neuro- and reproductive toxicity are required. Here we discuss the use of a Galliformes-based avian test battery in which developmental toxicity is assessed by means of a combination of chemical exposure during early embryonic development using an embryo culture system followed by analyses after hatching of sociosexual behaviors such as aggression and mating and of visual memory via filial imprinting. This Galliformes-based avian test battery shows promise as a sophisticated means not only of assessing chemical toxicity in avian species but also of assessing the risks posed to higher vertebrates, including humans, which are markedly sensitive to nervous or neuroendocrine system dysfunction. PMID:27445667

  14. Avian Test Battery for the Evaluation of Developmental Abnormalities of Neuro- and Reproductive Systems

    PubMed Central

    Kawashima, Takaharu; Ahmed, Walaa M. S.; Nagino, Koki; Ubuka, Takayoshi; Tsutsui, Kazuyoshi

    2016-01-01

    Most of the currently used toxicity assays for environmental chemicals use acute or chronic systemic or reproductive toxicity endpoints rather than neurobehavioral endpoints. In addition, the current standard approaches to assess reproductive toxicity are time-consuming. Therefore, with increasing numbers of chemicals being developed with potentially harmful neurobehavioral effects in higher vertebrates, including humans, more efficient means of assessing neuro- and reproductive toxicity are required. Here we discuss the use of a Galliformes-based avian test battery in which developmental toxicity is assessed by means of a combination of chemical exposure during early embryonic development using an embryo culture system followed by analyses after hatching of sociosexual behaviors such as aggression and mating and of visual memory via filial imprinting. This Galliformes-based avian test battery shows promise as a sophisticated means not only of assessing chemical toxicity in avian species but also of assessing the risks posed to higher vertebrates, including humans, which are markedly sensitive to nervous or neuroendocrine system dysfunction. PMID:27445667

  15. 78 FR 65583 - Capital Planning and Stress Testing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

    ... stress tests.\\3\\ \\1\\ 76 FR 74631 (Dec. 1, 2011). \\2\\ Id. \\3\\ See 77 FR 61238 (Oct. 9, 2012); 77 FR 62378 (Oct. 12, 2012); 77 FR 62396 (Oct. 12, 2012); 77 FR 62417 (Oct. 15, 2012). II. Proposed Rule A. Credit..., prepares them to do this. \\5\\ See 78 FR 62018 (Oct. 11, 2013). The net worth ratio contains components...

  16. Prognostic impact of stress testing in coronary artery disease

    SciTech Connect

    Severi, S.; Michelassi, C. )

    1991-05-01

    Observational data prospectively collected permit the examination of a complex set of decisions, including the decision not to perform any stress testing. Patients with or without previous myocardial infarction admitted for coronary evaluation and not submitted to any stress testing because of clinical reasons are at a higher risk for subsequent death. For prognostication, no test has been better validated than exercise electrocardiography: it can identify patients at low and high risk for future cardiac events among those without symptoms, with typical chest pain, and with previous myocardial infarction. In patients with triple-vessel disease, the results of exercise also allow those at low and high risk to be recognized. Both exercise radionuclide angiography and {sup 201}Tl scintigraphy (the latter in larger patient populations) have also demonstrated significant prognostic value on patients with or without previous myocardial infarction. Neither one has shown superiority to the other in prognostication. So far, they have been considered the only viable alternatives to exercise electrocardiography stress testing for diagnosis and prognostication. However, their costs limit their extensive application. Preliminary data suggest that intravenous dipyridamole echocardiography can be used for both diagnosis and prognostication of coronary artery disease; moreover, the prognostic information derived from dipyridamole echocardiography testing seems independent of and additive to that provided by exercise electrocardiography. Further prospective studies on larger patient populations are needed to better define the prognostic value of dipyridamole echocardiography testing.47 references.

  17. Psychological and endocrine abnormalities in refugees from East Germany: Part I. Prolonged stress, psychopathology, and hypothalamic-pituitary-thyroid axis activity.

    PubMed

    Bauer, M; Priebe, S; Kürten, I; Gräf, K J; Baumgartner, A

    1994-01-01

    The influence of prolonged psychological stress on hormonal secretion was investigated in 84 East Germany refugees suffering from psychiatric disorders within 6 weeks of their arrival in West Berlin shortly before or after the fall of the Berlin Wall. Before leaving the German Democratic Republic, these patients had already experienced prolonged stress, which continued after migration. In most cases, the diagnosis was anxious-depressive syndrome with vegetative complaints and symptoms of increased arousal. Their formal DSM-III-R diagnoses (American Psychiatric Association, 1987) included adjustment disorders, depressive disorders, and anxiety disorders (the latter including posttraumatic stress disorder). Serum levels of thyroid stimulating hormone (TSH) and thyroid hormones (thyroxine, free thyroxine, triiodothyronine, and reverse triiodothyronine) were measured and compared with those of 20 healthy control subjects. TSH and all thyroid hormone concentrations were significantly reduced in the patient group. Fifty-two of the patients (62%) were in the hypothyroid range but did not show any clinical signs of hypothyroidism. These disturbances in hormonal secretion were not correlated to any psychiatric diagnosis or to the severity of acute or chronic stress. The marked abnormalities in the hypothalamic-pituitary-thyroid axis seen in these refugees differ from those reported in depression and would seem to reflect severe chronic stress rather than specific psychiatric disorders. The underlying neurochemical mechanisms remain to be investigated.

  18. Strain Measurement Using FBG on COPV in Stress Rupture Test

    NASA Technical Reports Server (NTRS)

    Banks, Curtis; Grant, Joseph

    2007-01-01

    White Sands Test Facility (WSTF) was requested to perform ambient temperature hydrostatic pressurization testing of a Space Transportation System (STS) 40-in. Kevlar Composite Overwrapped Pressure Vessel (COPV). The 40-in. vessel was of the same design and approximate age as the STS Main Propulsion System (MPS) and Orbiter Maneuvering System (OMS) vessels. The NASA Engineering Safety Center (NESC) assembled a team of experts and conducted an assessment that involved a review of national Kevlar COPY data. During the review, the STS COPVs were found to be beyond their original certification of ten years. The team observed that the likelihood of STS COPV Stress rupture, a catastrophic burst before leak failure mode, was greater than previously believed. Consequently, a detailed assessment of remaining stress rupture life became necessary. Prior to STS-114, a certification deviation was written for two flights of OV-103 (Discovery) and OV-104 (Atlantis) per rationale that was based on an extensive review of the Lawrence Livermore National Laboratories, COPV data, and revisions to the STS COPV stress levels. In order to obtain flight rationale to extend the certification deviation through the end of the Program, the Orbiter Project Office has directed an interagency COPV team to conduct further testing and analysis to investigate conservatism in the stress rupture model and evaluate material age degradation. Additional analysis of stress rupture life requires understanding the fiber stresses including stress that occurs due to thru-wall composite compression in COPV components. Data must be obtained at both zero gauge pressure (pre-stress) and at the component operating pressure so that this phenomenon can be properly evaluated. The zero gauge pressure stresses are predominantly a result of the autofrettage process used during vessel manufacture. Determining these pre-stresses and the constitutive behavior of the overwrap at pressure will provide necessary information

  19. ECG in stress testing: child of a lesser diagnostic god?

    PubMed

    Longo, S; Del Negro, B; Picano, E

    1997-01-01

    When new technologies are added to the previously existing ones, the latter can be prematurely discarded and judged obsolete not only on the basis of rational scientific facts, but also on irrational trends. Old techniques, like electrocardiography, suffer from diagnostic ambiguities that can be solved by combination with a cardiac imaging technique, like stress echocardiography. ECG monitoring during all forms of stress testing can still offer surprising dividends for a better understanding of the complex physiology of coronary artery disease, a better clinical characterization of patients with microvascular angina, and may serve as an important adjunct marker to cardiac imaging techniques. PMID:9350596

  20. Developing and testing a multi-probe resonance electrical impedance spectroscopy system for detecting breast abnormalities

    NASA Astrophysics Data System (ADS)

    Gur, David; Zheng, Bin; Dhurjaty, Sreeram; Wolfe, Gene; Fradin, Mary; Weil, Richard; Sumkin, Jules; Zuley, Margarita

    2009-02-01

    In our previous study, we reported on the development and preliminary testing of a prototype resonance electrical impedance spectroscopy (REIS) system with a pair of probes. Although our pilot study on 150 young women ranging from 30 to 50 years old indicated the feasibility of using REIS output sweep signals to classify between the women who had negative examinations and those who would ultimately be recommended for biopsy, the detection sensitivity was relatively low. To improve performance when using REIS technology, we recently developed a new multi-probe based REIS system. The system consists of a sensor module box that can be easily lifted along a vertical support device to fit women of different height. Two user selectable breast placement "cups" with different curvatures are included in the system. Seven probes are mounted on each of the cups on opposing sides of the sensor box. By rotating the sensor box, the technologist can select the detection sensor cup that better fits the breast size of the woman being examined. One probe is mounted in the cup center for direct contact with the nipple and the other six probes are uniformly distributed along an outside circle to enable contact with six points on the outer and inner breast skin surfaces. The outer probes are located at a distance of 60mm away from the center (nipple) probe. The system automatically monitors the quality of the contact between the breast surface and each of the seven probes and data acquisition can only be initiated when adequate contact is confirmed. The measurement time for each breast is approximately 15 seconds during which time the system records 121 REIS signal sweep outputs generated from 200 KHz to 800 KHz at 5 KHz increments for all preselected probe pairs. Currently we are measuring 6 pairs between the center probe and each of six probes located on the outer circle as well as two pairs between probe pairs on the outer circle. This new REIS system has been installed in our

  1. Genetic susceptibility testing from a stress and coping perspective.

    PubMed

    Gooding, Holly C; Organista, Kurt; Burack, Jeffrey; Biesecker, Barbara Bowles

    2006-04-01

    Four theories of health behavior and of stress and coping are reviewed for their ability to illuminate interest in uptake and outcomes of genetic testing for adult-onset diseases. These theories are the Health Belief Model, the Theory of Planned Behavior (TPB), the Common Sense Model of Self-regulation (CSM), and the Transactional Model of Stress and Coping (TMSC). Basic concepts of each theory are discussed, followed by evidence from the literature supporting the relevance of these concepts to the understanding of genetic testing for four adult-onset diseases: Huntington's disease, Alzheimer's disease, hereditary breast/ovarian cancer, and hereditary colorectal cancer. Emphasis is placed on the finding that a decision to undergo genetic testing may be considered as a way to cope with both the cognitive and affective concerns that arise from living at increased risk of developing a disease in the future. The potential value of genetic testing for reducing uncertainty about and gaining a sense of control over one's risk of developing a chronic disease is highlighted. We argue that theories which focus on stress and coping provide a useful framework for future studies of genetic testing decisions for adult-onset disease risk.

  2. Acute Anteroseptal Myocardial Infarction after a Negative Exercise Stress Test.

    PubMed

    Al-Alawi, Abdullah M; Janardan, Jyotsna; Peck, Kah Y; Soward, Alan

    2016-05-01

    A myocardial infarction is a rare complication which can occur after an exercise stress test. We report a 48-year-old male who was referred to the Mildura Cardiology Practice, Victoria, Australia, in August 2014 with left-sided chest pain. He underwent an exercise stress test which was negative for myocardial ischaemia. However, the patient presented to the Emergency Department of the Mildura Base Hospital 30 minutes after the test with severe retrosternal chest pain. An acute anteroseptal ST segment elevation myocardial infarction was observed on electrocardiography. After thrombolysis, he was transferred to a tertiary hospital where coronary angiography subsequently revealed significant left anterior descending coronary artery stenosis. Thrombus aspiration and a balloon angioplasty were performed. The patient was discharged three days after the surgical procedure in good health.

  3. A prognostic scoring system for arm exercise stress testing

    PubMed Central

    Xie, Yan; Xian, Hong; Chandiramani, Pooja; Bainter, Emily; Wan, Leping; Martin, Wade H

    2016-01-01

    Objective Arm exercise stress testing may be an equivalent or better predictor of mortality outcome than pharmacological stress imaging for the ≥50% for patients unable to perform leg exercise. Thus, our objective was to develop an arm exercise ECG stress test scoring system, analogous to the Duke Treadmill Score, for predicting outcome in these individuals. Methods In this retrospective observational cohort study, arm exercise ECG stress tests were performed in 443 consecutive veterans aged 64.1 (11.1) years. (mean (SD)) between 1997 and 2002. From multivariate Cox models, arm exercise scores were developed for prediction of 5-year and 12-year all-cause and cardiovascular mortality and 5-year cardiovascular mortality or myocardial infarction (MI). Results Arm exercise capacity in resting metabolic equivalents (METs), 1 min heart rate recovery (HRR) and ST segment depression ≥1 mm were the stress test variables independently associated with all-cause and cardiovascular mortality by step-wise Cox analysis (all p<0.01). A score based on the relation HRR (bpm)+7.3×METs−10.5×ST depression (0=no; 1=yes) prognosticated 5-year cardiovascular mortality with a C-statistic of 0.81 before and 0.88 after adjustment for significant demographic and clinical covariates. Arm exercise scores for the other outcome end points yielded C-statistic values of 0.77–0.79 before and 0.82–0.86 after adjustment for significant covariates versus 0.64–0.72 for best fit pharmacological myocardial perfusion imaging models in a cohort of 1730 veterans who were evaluated over the same time period. Conclusions Arm exercise scores, analogous to the Duke Treadmill Score, have good power for prediction of mortality or MI in patients who cannot perform leg exercise. PMID:26835142

  4. Stress Free Temperature Testing and Residual Stress Calculations on Out-of-Autoclave Composites

    NASA Technical Reports Server (NTRS)

    Cox, Sarah; Tate, LaNetra C.; Danley, Susan; Sampson, Jeff; Taylor, Brian; Miller, Sandi

    2012-01-01

    Future launch vehicles will require the incorporation large composite parts that will make up primary and secondary components of the vehicle. NASA has explored the feasibility of manufacturing these large components using Out-of-Autoclave impregnated carbon fiber composite systems through many composites development projects. Most recently, the Composites for Exploration Project has been looking at the development of a 10 meter diameter fairing structure, similar in size to what will be required for a heavy launch vehicle. The development of new material systems requires the investigation of the material properties and the stress in the parts. Residual stress is an important factor to incorporate when modeling the stresses that a part is undergoing. Testing was performed to verify the stress free temperature with two-ply asymmetric panels. A comparison was done between three newly developed out of autoclave IM7 /Bismalieimide (BMI) systems. This paper presents the testing results and the analysis performed to determine the residual stress of the materials.

  5. Noninvasive stress testing - Methodology for elimination of the phonocardiogram

    NASA Technical Reports Server (NTRS)

    Spodick, D. H.; Lance, V. Q.

    1976-01-01

    Measurement by systolic time intervals (STI) of cardiac responses requires extremely careful recording during actual stress test performance. Previous work indicated no significant changes in the pulse transmission time (PTT) during exercise and other challenges. Since external STI depend on the carotid pulse offset by the PTT as an aortic curve equivalent, stable PTT implies that timing of the carotid upstroke and the carotid incisura would respectively track the pre-ejection period and the aortic incisura. In ten subjects, STIs were recorded at supine rest, sitting, standing, during prompt and sustained squatting and during isometric and dynamic exercise. The results demonstrated the tracking of both points. Coefficients of correlation and of determination were uniformly high for all challenges except isometric handgrip (IHG). Since left ventricular ejection time is obtained directly from the pulse curve, with the exception of IHG, STI responses during stress testing can be measured without a phonocardiogram.

  6. Step-Stress Accelerated Degradation Testing (SSADT) for Photovoltaic (PV) Devices and Cells (Presentation)

    SciTech Connect

    Lee, J.; Elmore, R.; Suh, C.; Jones, W.

    2010-10-01

    Presentation on step-stress accelerated degradation testing (SSADT) for photovoltaics (PV). Developed are a step-stress degradation test (SSADT) for PV reliability tests and a lifetime prediction model for PV products.

  7. A review of research trends in physiological abnormalities in autism spectrum disorders: immune dysregulation, inflammation, oxidative stress, mitochondrial dysfunction and environmental toxicant exposures

    PubMed Central

    Rossignol, D A; Frye, R E

    2012-01-01

    Recent studies have implicated physiological and metabolic abnormalities in autism spectrum disorders (ASD) and other psychiatric disorders, particularly immune dysregulation or inflammation, oxidative stress, mitochondrial dysfunction and environmental toxicant exposures (‘four major areas'). The aim of this study was to determine trends in the literature on these topics with respect to ASD. A comprehensive literature search from 1971 to 2010 was performed in these four major areas in ASD with three objectives. First, publications were divided by several criteria, including whether or not they implicated an association between the physiological abnormality and ASD. A large percentage of publications implicated an association between ASD and immune dysregulation/inflammation (416 out of 437 publications, 95%), oxidative stress (all 115), mitochondrial dysfunction (145 of 153, 95%) and toxicant exposures (170 of 190, 89%). Second, the strength of evidence for publications in each area was computed using a validated scale. The strongest evidence was for immune dysregulation/inflammation and oxidative stress, followed by toxicant exposures and mitochondrial dysfunction. In all areas, at least 45% of the publications were rated as providing strong evidence for an association between the physiological abnormalities and ASD. Third, the time trends in the four major areas were compared with trends in neuroimaging, neuropathology, theory of mind and genetics (‘four comparison areas'). The number of publications per 5-year block in all eight areas was calculated in order to identify significant changes in trends. Prior to 1986, only 12 publications were identified in the four major areas and 51 in the four comparison areas (42 for genetics). For each 5-year period, the total number of publications in the eight combined areas increased progressively. Most publications (552 of 895, 62%) in the four major areas were published in the last 5 years (2006–2010). Evaluation

  8. Inhibition of NAPDH Oxidase 2 (NOX2) Prevents Oxidative Stress and Mitochondrial Abnormalities Caused by Saturated Fat in Cardiomyocytes.

    PubMed

    Joseph, Leroy C; Barca, Emanuele; Subramanyam, Prakash; Komrowski, Michael; Pajvani, Utpal; Colecraft, Henry M; Hirano, Michio; Morrow, John P

    2016-01-01

    Obesity and high saturated fat intake increase the risk of heart failure and arrhythmias. The molecular mechanisms are poorly understood. We hypothesized that physiologic levels of saturated fat could increase mitochondrial reactive oxygen species (ROS) in cardiomyocytes, leading to abnormalities of calcium homeostasis and mitochondrial function. We investigated the effect of saturated fat on mitochondrial function and calcium homeostasis in isolated ventricular myocytes. The saturated fatty acid palmitate causes a decrease in mitochondrial respiration in cardiomyocytes. Palmitate, but not the monounsaturated fatty acid oleate, causes an increase in both total cellular ROS and mitochondrial ROS. Palmitate depolarizes the mitochondrial inner membrane and causes mitochondrial calcium overload by increasing sarcoplasmic reticulum calcium leak. Inhibitors of PKC or NOX2 prevent mitochondrial dysfunction and the increase in ROS, demonstrating that PKC-NOX2 activation is also required for amplification of palmitate induced-ROS. Cardiomyocytes from mice with genetic deletion of NOX2 do not have palmitate-induced ROS or mitochondrial dysfunction. We conclude that palmitate induces mitochondrial ROS that is amplified by NOX2, causing greater mitochondrial ROS generation and partial depolarization of the mitochondrial inner membrane. The abnormal sarcoplasmic reticulum calcium leak caused by palmitate could promote arrhythmia and heart failure. NOX2 inhibition is a potential therapy for heart disease caused by diabetes or obesity. PMID:26756466

  9. Inhibition of NAPDH Oxidase 2 (NOX2) Prevents Oxidative Stress and Mitochondrial Abnormalities Caused by Saturated Fat in Cardiomyocytes

    PubMed Central

    Joseph, Leroy C.; Barca, Emanuele; Subramanyam, Prakash; Komrowski, Michael; Pajvani, Utpal; Colecraft, Henry M.; Hirano, Michio; Morrow, John P.

    2016-01-01

    Obesity and high saturated fat intake increase the risk of heart failure and arrhythmias. The molecular mechanisms are poorly understood. We hypothesized that physiologic levels of saturated fat could increase mitochondrial reactive oxygen species (ROS) in cardiomyocytes, leading to abnormalities of calcium homeostasis and mitochondrial function. We investigated the effect of saturated fat on mitochondrial function and calcium homeostasis in isolated ventricular myocytes. The saturated fatty acid palmitate causes a decrease in mitochondrial respiration in cardiomyocytes. Palmitate, but not the monounsaturated fatty acid oleate, causes an increase in both total cellular ROS and mitochondrial ROS. Palmitate depolarizes the mitochondrial inner membrane and causes mitochondrial calcium overload by increasing sarcoplasmic reticulum calcium leak. Inhibitors of PKC or NOX2 prevent mitochondrial dysfunction and the increase in ROS, demonstrating that PKC-NOX2 activation is also required for amplification of palmitate induced-ROS. Cardiomyocytes from mice with genetic deletion of NOX2 do not have palmitate-induced ROS or mitochondrial dysfunction. We conclude that palmitate induces mitochondrial ROS that is amplified by NOX2, causing greater mitochondrial ROS generation and partial depolarization of the mitochondrial inner membrane. The abnormal sarcoplasmic reticulum calcium leak caused by palmitate could promote arrhythmia and heart failure. NOX2 inhibition is a potential therapy for heart disease caused by diabetes or obesity. PMID:26756466

  10. 12 CFR 252.154 - Annual stress test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... by this section. The Board may also require a state member bank that is subject to 12 CFR part 208, appendix E and that is a subsidiary of a bank holding company subject to this § 252.154(b)(2)(i) or 12 CFR... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Annual stress test. 252.154 Section...

  11. Stress Tests for Chest Pain: When You Need an Imaging Test -- and When You Don't

    MedlinePlus

    ... Patient Resources Stress Tests for Chest Pain Stress Tests for Chest Pain When you need an imaging test—and when you don’t DOWNLOAD PDF If ... that suggests you might have heart disease, a test that stresses the heart can help you and ...

  12. Stress echocardiography

    MedlinePlus

    Echocardiography stress test; Stress test - echocardiography; CAD - stress echocardiography; Coronary artery disease - stress echocardiography; Chest pain - stress echocardiography; Angina - stress echocardiography; ...

  13. Terahertz NDE of Stressed Composite Overwrapped Pressure Vessels - Initial Testing

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Seebo, Jeffrey P.; Anatasi, Robert F.

    2009-01-01

    Terahertz radiation nondestructive evaluation was applied to a set of Kevlar composite overwrapped pressure vessel bottles that had undergone a series of thermal and pressure tests to simulate stress rupture effects. The bottles in these nondestructive evaluation tests were bottles that had not ruptured but had survived various times at the elevated load and temperature levels. Some of the bottles showed evidence of minor composite failures. The terahertz radiation did detect visible surface flaws, but did not detect any internal chemical or material degradation of the thin overwraps.

  14. Involvement of oxidative stress-induced abnormalities in ceramide and cholesterol metabolism in brain aging and Alzheimer's disease

    NASA Astrophysics Data System (ADS)

    Cutler, Roy G.; Kelly, Jeremiah; Storie, Kristin; Pedersen, Ward A.; Tammara, Anita; Hatanpaa, Kimmo; Troncoso, Juan C.; Mattson, Mark P.

    2004-02-01

    Alzheimer's disease (AD) is an age-related disorder characterized by deposition of amyloid -peptide (A) and degeneration of neurons in brain regions such as the hippocampus, resulting in progressive cognitive dysfunction. The pathogenesis of AD is tightly linked to A deposition and oxidative stress, but it remains unclear as to how these factors result in neuronal dysfunction and death. We report alterations in sphingolipid and cholesterol metabolism during normal brain aging and in the brains of AD patients that result in accumulation of long-chain ceramides and cholesterol. Membrane-associated oxidative stress occurs in association with the lipid alterations, and exposure of hippocampal neurons to A induces membrane oxidative stress and the accumulation of ceramide species and cholesterol. Treatment of neurons with -tocopherol or an inhibitor of sphingomyelin synthesis prevents accumulation of ceramides and cholesterol and protects them against death induced by A. Our findings suggest a sequence of events in the pathogenesis of AD in which A induces membrane-associated oxidative stress, resulting in perturbed ceramide and cholesterol metabolism which, in turn, triggers a neurodegenerative cascade that leads to clinical disease. amyloid | apoptosis | hippocampus | lipid peroxidation | sphingomyelin

  15. Abnormal Osmotic Avoidance Behavior in C. elegans Is Associated with Increased Hypertonic Stress Resistance and Improved Proteostasis

    PubMed Central

    Lee, Elaine C.; Kim, Heejung; Ditano, Jennifer; Manion, Dacie; King, Benjamin L.; Strange, Kevin

    2016-01-01

    Protein function is controlled by the cellular proteostasis network. Proteostasis is energetically costly and those costs must be balanced with the energy needs of other physiological functions. Hypertonic stress causes widespread protein damage in C. elegans. Suppression and management of protein damage is essential for optimal survival under hypertonic conditions. ASH chemosensory neurons allow C. elegans to detect and avoid strongly hypertonic environments. We demonstrate that mutations in osm-9 and osm-12 that disrupt ASH mediated hypertonic avoidance behavior or genetic ablation of ASH neurons are associated with enhanced survival during hypertonic stress. Improved survival is not due to altered systemic volume homeostasis or organic osmolyte accumulation. Instead, we find that osm-9(ok1677) mutant and osm-9(RNAi) worms exhibit reductions in hypertonicity induced protein damage in non-neuronal cells suggesting that enhanced proteostasis capacity may account for improved hypertonic stress resistance in worms with defects in osmotic avoidance behavior. RNA-seq analysis revealed that genes that play roles in managing protein damage are upregulated in osm-9(ok1677) worms. Our findings are consistent with a growing body of work demonstrating that intercellular communication between neuronal and non-neuronal cells plays a critical role in integrating cellular stress resistance with other organismal physiological demands and associated energy costs. PMID:27111894

  16. Abnormal Osmotic Avoidance Behavior in C. elegans Is Associated with Increased Hypertonic Stress Resistance and Improved Proteostasis.

    PubMed

    Lee, Elaine C; Kim, Heejung; Ditano, Jennifer; Manion, Dacie; King, Benjamin L; Strange, Kevin

    2016-01-01

    Protein function is controlled by the cellular proteostasis network. Proteostasis is energetically costly and those costs must be balanced with the energy needs of other physiological functions. Hypertonic stress causes widespread protein damage in C. elegans. Suppression and management of protein damage is essential for optimal survival under hypertonic conditions. ASH chemosensory neurons allow C. elegans to detect and avoid strongly hypertonic environments. We demonstrate that mutations in osm-9 and osm-12 that disrupt ASH mediated hypertonic avoidance behavior or genetic ablation of ASH neurons are associated with enhanced survival during hypertonic stress. Improved survival is not due to altered systemic volume homeostasis or organic osmolyte accumulation. Instead, we find that osm-9(ok1677) mutant and osm-9(RNAi) worms exhibit reductions in hypertonicity induced protein damage in non-neuronal cells suggesting that enhanced proteostasis capacity may account for improved hypertonic stress resistance in worms with defects in osmotic avoidance behavior. RNA-seq analysis revealed that genes that play roles in managing protein damage are upregulated in osm-9(ok1677) worms. Our findings are consistent with a growing body of work demonstrating that intercellular communication between neuronal and non-neuronal cells plays a critical role in integrating cellular stress resistance with other organismal physiological demands and associated energy costs.

  17. Relations among Detection of Syllable Stress, Speech Abnormalities, and Communicative Ability in Adults with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Kargas, Niko; López, Beatriz; Morris, Paul; Reddy, Vasudevi

    2016-01-01

    Purpose: To date, the literature on perception of affective, pragmatic, and grammatical prosody abilities in autism spectrum disorders (ASD) has been sparse and contradictory. It is interesting to note that the primary perception of syllable stress within the word structure, which is crucial for all prosody functions, remains relatively unexplored…

  18. Meiotic abnormalities

    SciTech Connect

    1993-12-31

    Chapter 19, describes meiotic abnormalities. These include nondisjunction of autosomes and sex chromosomes, genetic and environmental causes of nondisjunction, misdivision of the centromere, chromosomally abnormal human sperm, male infertility, parental age, and origin of diploid gametes. 57 refs., 2 figs., 1 tab.

  19. Pharmacological modulation of stress-induced behavioral changes in the light/dark exploration test in male C57BL/6J mice.

    PubMed

    Ihne, Jessica L; Fitzgerald, Paul J; Hefner, Kathryn R; Holmes, Andrew

    2012-01-01

    Psychological stress is a major risk factor for mood and anxiety disorders. However, the phenotypic manifestation of stress effects varies across individuals, likely due, in part, to genetic variation. Modeling the behavioral and neural consequences of stress across genetically diverse inbred mouse strains is a valuable approach to studying gene × stress interactions. Recent work has shown that C57BL/6J mice exposed to ten daily sessions of restraint stress exhibited increased exploration of the aversive light compartment in the light/dark exploration (LDE) test. Here we sought to clarify the nature of this stress-induced phenotype by testing the ability of treatment with various clinically efficacious drugs of different therapeutic classes to rescue it. Ten days of restraint increased light compartment exploration, reduced body weight and sensitized the corticosterone response to swim stress. Subchronic administration (during stress and LDE testing) of fluoxetine, and to a lesser extent, lithium chloride, rescued stress-induced LDE behavior. Chronic fluoxetine treatment prior to (plus during stress and testing) failed to block the LDE stress effect. Acute administration of antipsychotic haloperidol, anti-ADHD medication methylphenidate or anxiolytic drug chlordiazepoxide, prior to LDE testing, was also unable to normalize the LDE stress effect. Collectively, these data demonstrate a treatment-selective prophylactic rescue of a restraint stress-induced behavioral abnormality in the C57BL/6J inbred strain. Further work with this novel model could help elucidate genetic and neural mechanisms mediating stress-induced changes in mouse 'emotion-relevant' behaviors and, ultimately, further understanding of the pathophysiology of stress-related neuropsychiatric disorders. This article is part of a Special Issue entitled 'Anxiety and Depression'.

  20. Stress Analysis and Permeability Testing of Cryogenic Composite Feed Line

    NASA Technical Reports Server (NTRS)

    Chu, Tsuchin Philip

    1999-01-01

    For the next generation Single-Stage-To-Orbit (SSTO) Reusable Launch Vehicle (RLV), the use of advanced composite materials is highly desirable and critical to the success of the mission. NASA Marshall Space Flight Center (MSFC) has been working with the aerospace industry for many years to develop and demonstrate the cryogenic composite propellant tanks and feed lines technologies. A 50.8-mm diameter composite feed line for the Clipper Graham (DCY.A) was developed and tested. The purpose of the program is to demonstrate the LH2 permeability, composite to composite and metal joints, as well as composite flange interface of the composite feed line. Stress analysis and permeability testing have been performed on this article. Recently, a larger composite feed line design is being investigated and developed at MSFC for potential use in future RLV. The diameter of the feed line is 203 mm and the overall length is approximately 2.2 meters. This one piece unlined feed line consists of three straight tubular sections joined by two 90 degree elbows. The material chosen is IM7/977-3 prepreg fabric. The lay-up pattern is [0/90, plus or minus 45]s and is built up to 18 plies to the flanges at both ends. A preliminary stress analysis has been conducted to identify potential critical stresses and to develop the finite element analysis (FEA) capability of composite feed lines. As expected, the critical stresses occurred at the rims of some flange holes and the onset of the tapered tubular sections. Further analysis is required to determine the loads, flange deflection, vibration, and combined maximum loads. Two permeability-testing apparatuses were also designed for both flat panel specimens and curved feed line sections after impact damage. A larger permeant gas exposed area is required to accurately determine the effect of impact damage on the permeability of the feed line materials. The flat panel tester was fabricated and assembled. Three test coupons were made of graphite

  1. Accelerated stress testing of thin film solar cells: Development of test methods and preliminary results

    NASA Technical Reports Server (NTRS)

    Lathrop, J. W.

    1985-01-01

    If thin film cells are to be considered a viable option for terrestrial power generation their reliability attributes will need to be explored and confidence in their stability obtained through accelerated testing. Development of a thin film accelerated test program will be more difficult than was the case for crystalline cells because of the monolithic construction nature of the cells. Specially constructed test samples will need to be fabricated, requiring committment to the concept of accelerated testing by the manufacturers. A new test schedule appropriate to thin film cells will need to be developed which will be different from that used in connection with crystalline cells. Preliminary work has been started to seek thin film schedule variations to two of the simplest tests: unbiased temperature and unbiased temperature humidity. Still to be examined are tests which involve the passage of current during temperature and/or humidity stress, either by biasing in the forward (or reverse) directions or by the application of light during stress. Investigation of these current (voltage) accelerated tests will involve development of methods of reliably contacting the thin conductive films during stress.

  2. Brain magnetic resonance imaging CO2 stress testing in adolescent postconcussion syndrome.

    PubMed

    Mutch, W Alan C; Ellis, Michael J; Ryner, Lawrence N; Ruth Graham, M; Dufault, Brenden; Gregson, Brian; Hall, Thomas; Bunge, Martin; Essig, Marco; Fisher, Joseph A; Duffin, James; Mikulis, David J

    2016-09-01

    OBJECT A neuroimaging assessment tool to visualize global and regional impairments in cerebral blood flow (CBF) and cerebrovascular responsiveness in individual patients with concussion remains elusive. Here the authors summarize the safety, feasibility, and results of brain CO2 stress testing in adolescents with postconcussion syndrome (PCS) and healthy controls. METHODS This study was approved by the Biomedical Research Ethics Board at the University of Manitoba. Fifteen adolescents with PCS and 17 healthy control subjects underwent anatomical MRI, pseudo-continuous arterial spin labeling MRI, and brain stress testing using controlled CO2 challenge and blood oxygen level-dependent (BOLD) MRI. Post hoc processing was performed using statistical parametric mapping to determine voxel-by-voxel regional resting CBF and cerebrovascular responsiveness of the brain to the CO2 stimulus (increase in BOLD signal) or the inverse (decrease in BOLD signal). Receiver operating characteristic (ROC) curves were generated to compare voxel counts categorized by control (0) or PCS (1). RESULTS Studies were well tolerated without any serious adverse events. Anatomical MRI was normal in all study participants. No differences in CO2 stimuli were seen between the 2 participant groups. No group differences in global mean CBF were detected between PCS patients and healthy controls. Patient-specific differences in mean regional CBF and CO2 BOLD responsiveness were observed in all PCS patients. The ROC curve analysis for brain regions manifesting a voxel response greater than and less than the control atlas (that is, abnormal voxel counts) produced an area under the curve of 0.87 (p < 0.0001) and 0.80 (p = 0.0003), respectively, consistent with a clinically useful predictive model. CONCLUSIONS Adolescent PCS is associated with patient-specific abnormalities in regional mean CBF and BOLD cerebrovascular responsiveness that occur in the setting of normal global resting CBF. Future prospective

  3. Step-Stress Accelerated Degradation Testing for Solar Reflectors: Preprint

    SciTech Connect

    Jones, W.; Elmore, R.; Lee, J.; Kennedy, C.

    2011-09-01

    To meet the challenge to reduce the cost of electricity generated with concentrating solar power (CSP) new low-cost reflector materials are being developed including metalized polymer reflectors and must be tested and validated against appropriate failure mechanisms. We explore the application of testing methods and statistical inference techniques for quantifying estimates and improving lifetimes of concentrating solar power (CSP) reflectors associated with failure mechanisms initiated by exposure to the ultraviolet (UV) part of the solar spectrum. In general, a suite of durability and reliability tests are available for testing a variety of failure mechanisms where the results of a set are required to understand overall lifetime of a CSP reflector. We will focus on the use of the Ultra-Accelerated Weathering System (UAWS) as a testing device for assessing various degradation patterns attributable to accelerated UV exposure. Depending on number of samples, test conditions, degradation and failure patterns, test results may be used to derive insight into failure mechanisms, associated physical parameters, lifetimes and uncertainties. In the most complicated case warranting advanced planning and statistical inference, step-stress accelerated degradation (SSADT) methods may be applied.

  4. An Abnormal Nitric Oxide Metabolism Contributes to Brain Oxidative Stress in the Mouse Model for the Fragile X Syndrome, a Possible Role in Intellectual Disability

    PubMed Central

    Lima-Cabello, Elena; Garcia-Guirado, Francisco; Calvo-Medina, Rocio; el Bekay, Rajaa; Perez-Costillas, Lucia; Quintero-Navarro, Carolina; Sanchez-Salido, Lourdes

    2016-01-01

    Background. Fragile X syndrome is the most common genetic cause of mental disability. Although many research has been performed, the mechanism underlying the pathogenesis is unclear and needs further investigation. Oxidative stress played major roles in the syndrome. The aim was to investigate the nitric oxide metabolism, protein nitration level, the expression of NOS isoforms, and furthermore the activation of the nuclear factor NF-κB-p65 subunit in different brain areas on the fragile X mouse model. Methods. This study involved adult male Fmr1-knockout and wild-type mice as controls. We detected nitric oxide metabolism and the activation of the nuclear factor NF-κBp65 subunit, comparing the mRNA expression and protein content of the three NOS isoforms in different brain areas. Results. Fmr1-KO mice showed an abnormal nitric oxide metabolism and increased levels of protein tyrosine nitrosylation. Besides that, nuclear factor NF-κB-p65 and inducible nitric oxide synthase appeared significantly increased in the Fmr1-knockout mice. mRNA and protein levels of the neuronal nitric oxide synthase appeared significantly decreased in the knockout mice. However, the epithelial nitric oxide synthase isoform displayed no significant changes. Conclusions. These data suggest the potential involvement of an abnormal nitric oxide metabolism in the pathogenesis of the fragile X syndrome. PMID:26788253

  5. Stress reactivity to an electronic version of the Trier Social Stress Test: a pilot study

    PubMed Central

    Hawn, Sage E.; Paul, Lisa; Thomas, Suzanne; Miller, Stephanie; Amstadter, Ananda B.

    2015-01-01

    Social stressors that rely on the inclusion of confederates (i.e., Trier Social Stress Test, TSST) are often used in clinical laboratory research paradigms to elicit a measurable stress response in participants. Although effective, the TSST is labor intensive and may introduce error variance as a function of confederate race, gender, and/or response characteristics. The present study aimed to develop and validate an electronic version of the TSST (e-TSST). The primary aim was to compare the e-TSST to an e-neutral control condition; the exploratory aim was to compare the magnitude of stress response elicited by the e-TSST to that elicited by the traditional TSST. Forty-three healthy adults were randomized to the e-TSST or e-neutral condition. Subjective (participant-rated distress) and objective [cortisol, heart rate (HR), and blood pressure] indices of stress were collected prior to, and multiple times following, the stressor. Using archival data collected from 19 healthy participants exposed to the traditional TSST in a prior study, stress reactivity was compared between the electronic and traditional versions of the TSST. The e-TSST elicited significant increases in all measures of stress reactivity compared to the e-neutral condition, with the exception of HR. Results showed that the magnitude of subjective distress, BP, and HR responses elicited by the e-TSST did not differ significantly from that elicited by the traditional TSST. The traditional TSST elicited significantly higher cortisol than the e-TSST. Although these findings provide initial support for the development of electronic versions of the TSST, further refinement of the e-TSST is warranted prior to broad adoption of this technology. A refined, reliable e-TSST could allow for increased utilization of the TSST by enhancing convenience, reducing labor costs, and limiting potential error variance introduced by human confederates. PMID:26074862

  6. Craniofacial Abnormalities

    MedlinePlus

    ... of the skull and face. Craniofacial abnormalities are birth defects of the face or head. Some, like cleft ... palate, are among the most common of all birth defects. Others are very rare. Most of them affect ...

  7. Chromosome Abnormalities

    MedlinePlus

    ... decade, newer techniques have been developed that allow scientists and doctors to screen for chromosomal abnormalities without using a microscope. These newer methods compare the patient's DNA to a normal DNA ...

  8. Walking abnormalities

    MedlinePlus

    ... include: Arthritis of the leg or foot joints Conversion disorder (a psychological disorder) Foot problems (such as a ... injuries. For an abnormal gait that occurs with conversion disorder, counseling and support from family members are strongly ...

  9. Nail abnormalities

    MedlinePlus

    Beau's lines; Fingernail abnormalities; Spoon nails; Onycholysis; Leukonychia; Koilonychia; Brittle nails ... Just like the skin, the fingernails tell a lot about your health: ... the fingernail. These lines can occur after illness, injury to ...

  10. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate ('dynamic fatigue') testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rate in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  11. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate (dynamic fatigue) testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rates in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  12. The Ohio Patient Navigation Research Program (OPNRP): Does the American Cancer Society patient navigation model improve time to resolution among patients with abnormal screening tests?

    PubMed Central

    Paskett, Electra D.; Katz, Mira L.; Post, Douglas M.; Pennell, Michael L.; Young, Gregory S.; Seiber, Eric E.; Harrop, J. Phil; DeGraffinreid, Cecilia R.; Tatum, Cathy M.; Dean, Julie A.; Murray, David M.

    2013-01-01

    Background Patient navigation (PN) has been suggested as a way to reduce cancer health disparities; however, many models of PN exist and most have not been carefully evaluated. The goal of this study was to test the Ohio American Cancer Society model of PN as it relates to reducing time to diagnostic resolution among persons with abnormal breast, cervical, or colorectal cancer screening tests or symptoms. Methods 862 patients from 18 clinics participated in this group-randomized trial. Chart review documented the date of the abnormality and the date of resolution. The primary analysis used shared frailty models to test for the effect of PN on time to resolution. Crude Hazard Ratios (HR)were used since there was no evidence of confounding. Costs were tracked with a 52-item instrument that recorded fixed costs of running a PN program and operational costs of navigating patients. Results HRs became significant at 6 months; conditional on the random clinic effect, the resolution rate at 15 months was 65% higher in the PN arm (p=0.012 for difference in risk across arms; p=0.009) for an increase in relative risk over time. The cost of navigating to diagnostic resolution averaged $150 per participant. Conclusions Participants with abnormal cancer screening tests or symptoms resolved faster if assigned to PN compared to those not assigned to PN. The effect of PN became apparent beginning six months after detection of the abnormality. Impact PN may help address health disparities by reducing time to resolution after an abnormal cancer screening test. PMID:23045536

  13. Relationships between stress corrosion cracking tests and utility operating experience

    SciTech Connect

    Baum, Allen

    1999-10-22

    Several utility steam generator and stress corrosion cracking databases are synthesized with the view of identifying the crevice chemistry that is most consistent with the plant cracking data. Superheated steam and neutral solution environments are found to be inconsistent with the large variations in the observed SCC between different plants, different support plates within a plant, and different crevice locations. While the eddy current response of laboratory tests performed with caustic chemistries approximates the response of the most extensively affected steam generator tubes, the crack propagation kinetics in these tests differ horn plant experience. The observations suggest that there is a gradual conversion of the environment responsible for most steam generator ODSCC from a concentrated, alkaline-forming solution to a progressively more steam-enriched environment.

  14. 12 CFR 652.100 - Audit of the risk-based capital stress test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Audit of the risk-based capital stress test... the risk-based capital stress test. You must have a qualified, independent external auditor review your implementation of the risk-based capital stress test every 3 years and submit a copy of...

  15. 12 CFR 652.65 - Risk-based capital stress test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Risk-based capital stress test. 652.65 Section... CORPORATION FUNDING AND FISCAL AFFAIRS Risk-Based Capital Requirements § 652.65 Risk-based capital stress test. You will perform the risk-based capital stress test as described in summary form below and...

  16. 12 CFR 652.100 - Audit of the risk-based capital stress test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Audit of the risk-based capital stress test... the risk-based capital stress test. You must have a qualified, independent external auditor review your implementation of the risk-based capital stress test every 3 years and submit a copy of...

  17. 12 CFR 652.100 - Audit of the risk-based capital stress test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Audit of the risk-based capital stress test... the risk-based capital stress test. You must have a qualified, independent external auditor review your implementation of the risk-based capital stress test every 3 years and submit a copy of...

  18. 12 CFR 652.65 - Risk-based capital stress test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Risk-based capital stress test. 652.65 Section... CORPORATION FUNDING AND FISCAL AFFAIRS Risk-Based Capital Requirements § 652.65 Risk-based capital stress test. You will perform the risk-based capital stress test as described in summary form below and...

  19. 12 CFR 652.100 - Audit of the risk-based capital stress test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Audit of the risk-based capital stress test... the risk-based capital stress test. You must have a qualified, independent external auditor review your implementation of the risk-based capital stress test every 3 years and submit a copy of...

  20. 78 FR 59165 - Orders: Information Reporting With Respect to Stress Testing of Regulated Entities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-26

    ... AGENCY 12 CFR Part 1238 Orders: Information Reporting With Respect to Stress Testing of Regulated... entity) that has total consolidated assets of more than $10 billion to conduct annual stress tests to... advise the regulated entities of the scenarios to be used for the initial stress testing....

  1. 12 CFR 652.65 - Risk-based capital stress test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Risk-based capital stress test. 652.65 Section... CORPORATION FUNDING AND FISCAL AFFAIRS Risk-Based Capital Requirements § 652.65 Risk-based capital stress test. You will perform the risk-based capital stress test as described in summary form below and...

  2. 77 FR 62396 - Annual Company-Run Stress Test Requirements for Banking Organizations With Total Consolidated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-12

    ... FDIC invited public comment on proposed rules in January of 2012.\\9\\ \\9\\ Annual Stress Test, 77 FR 3408 (Jan. 24, 2012) (OCC); Annual Stress Test, 77 FR 3166 (Jan. 17, 2012) (FDIC). The Board is finalizing... the Board as specified in the Capital Assessments and Stress Testing information collection (FR...

  3. 12 CFR 652.65 - Risk-based capital stress test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Risk-based capital stress test. 652.65 Section... CORPORATION FUNDING AND FISCAL AFFAIRS Risk-Based Capital Requirements § 652.65 Risk-based capital stress test. You will perform the risk-based capital stress test as described in summary form below and...

  4. 12 CFR 652.65 - Risk-based capital stress test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Risk-based capital stress test. 652.65 Section... CORPORATION FUNDING AND FISCAL AFFAIRS Risk-Based Capital Requirements § 652.65 Risk-based capital stress test. You will perform the risk-based capital stress test as described in summary form below and...

  5. 12 CFR 652.100 - Audit of the risk-based capital stress test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Audit of the risk-based capital stress test... the risk-based capital stress test. You must have a qualified, independent external auditor review your implementation of the risk-based capital stress test every 3 years and submit a copy of...

  6. Testing the tenets of minority stress theory in workplace contexts.

    PubMed

    Velez, Brandon L; Moradi, Bonnie; Brewster, Melanie E

    2013-10-01

    The links of minority stressors (workplace discrimination, expectations of stigma, internalized heterosexism, and identity management strategies) with psychological distress and job satisfaction were examined in a sample of 326 sexual minority employees. Drawing from minority stress theory and the literature on the vocational experiences of sexual minority people, patterns of mediation and moderation were tested. Minority stressors were associated with greater distress and lower job satisfaction. A mediation model was supported in which the links of discrimination and internalized heterosexism with psychological distress were mediated by a concealment-focused identity management strategy (i.e., avoiding), and the links of discrimination, expectations of stigma, and internalized heterosexism with job satisfaction were mediated by a disclosure-focused identity management strategy (i.e., integrating). Tests of moderation indicated that for sexual minority women (but not men), the positive association of discrimination with distress was stronger at higher levels of internalized heterosexism than at lower levels. In addition, lower levels of internalized heterosexism and concealment strategies (i.e., counterfeiting and avoiding) and higher levels of a disclosure strategy (i.e., integrating) were associated with higher job satisfaction in the context of low discrimination, but this buffering effect disappeared as level of discrimination increased. The implications of these findings for minority stress research are discussed, and clinical recommendations are made.

  7. PEX13 deficiency in mouse brain as a model of Zellweger syndrome: abnormal cerebellum formation, reactive gliosis and oxidative stress

    PubMed Central

    Müller, C. Catharina; Nguyen, Tam H.; Ahlemeyer, Barbara; Meshram, Mallika; Santrampurwala, Nishreen; Cao, Siyu; Sharp, Peter; Fietz, Pamela B.; Baumgart-Vogt, Eveline; Crane, Denis I.

    2011-01-01

    SUMMARY Delayed cerebellar development is a hallmark of Zellweger syndrome (ZS), a severe neonatal neurodegenerative disorder. ZS is caused by mutations in PEX genes, such as PEX13, which encodes a protein required for import of proteins into the peroxisome. The molecular basis of ZS pathogenesis is not known. We have created a conditional mouse mutant with brain-restricted deficiency of PEX13 that exhibits cerebellar morphological defects. PEX13 brain mutants survive into the postnatal period, with the majority dying by 35 days, and with survival inversely related to litter size and weaning body weight. The impact on peroxisomal metabolism in the mutant brain is mixed: plasmalogen content is reduced, but very-long-chain fatty acids are normal. PEX13 brain mutants exhibit defects in reflex and motor development that correlate with impaired cerebellar fissure and cortical layer formation, granule cell migration and Purkinje cell layer development. Astrogliosis and microgliosis are prominent features of the mutant cerebellum. At the molecular level, cultured cerebellar neurons from E19 PEX13-null mice exhibit elevated levels of reactive oxygen species and mitochondrial superoxide dismutase-2 (MnSOD), and show enhanced apoptosis together with mitochondrial dysfunction. PEX13 brain mutants show increased levels of MnSOD in cerebellum. Our findings suggest that PEX13 deficiency leads to mitochondria-mediated oxidative stress, neuronal cell death and impairment of cerebellar development. Thus, PEX13-deficient mice provide a valuable animal model for investigating the molecular basis and treatment of ZS cerebellar pathology. PMID:20959636

  8. Improved Accelerated Stress Tests Based on Fuel Cell Vehicle Data

    SciTech Connect

    Patterson, Timothy; Motupally, Sathya

    2012-06-01

    UTC will led a top-tier team of industry and national laboratory participants to update and improve DOE’s Accelerated Stress Tests (AST’s) for hydrogen fuel cells. This in-depth investigation will focused on critical fuel cell components (e.g. membrane electrode assemblies - MEA) whose durability represented barriers for widespread commercialization of hydrogen fuel cell technology. UTC had access to MEA materials that had accrued significant load time under real-world conditions in PureMotion® 120 power plant used in transit buses. These materials are referred to as end-of-life (EOL) components in the rest of this document. Advanced characterization techniques were used to evaluate degradation mode progress using these critical cell components extracted from both bus power plants and corresponding materials tested using the DOE AST’s. These techniques were applied to samples at beginning-of-life (BOL) to serve as a baseline. These comparisons advised the progress of the various failure modes that these critical components were subjected to, such as membrane degradation, catalyst support corrosion, platinum group metal dissolution, and others. Gaps in the existing ASTs predicted the degradation observed in the field in terms of these modes were outlined. Using the gaps, new AST’s were recommended and tested to better reflect the degradation modes seen in field operation. Also, BOL components were degraded in a test vehicle at UTC designed to accelerate the bus field operation.

  9. Role of exercise stress test in master athletes

    PubMed Central

    Pigozzi, F; Spataro, A; Alabiso, A; Parisi, A; Rizzo, M; Fagnani, F; Di, S; Massazza, G; Maffulli, N

    2005-01-01

    Background: The effectiveness of cardiovascular screening in minimising the risk of athletic field deaths in master athletes is not known. Objective: To evaluate the prevalence and clinical significance of ST segment depression during a stress test in asymptomatic apparently healthy elderly athletes. Methods: A total of 113 male subjects aged over 60 were studied (79 trained and 34 sedentary); 88 of them (62 trained and 26 sedentary) were followed up for four years (mean 2.16 years for athletes, 1.26 years for sedentary subjects), with a resting 12 lead electrocardiogram (ECG), symptom limited exercise ECG on a cycle ergometer, echocardiography, and 24 hour ECG Holter monitoring. Results: A significant ST segment depression at peak exercise was detected in one athlete at the first evaluation. A further case was seen during the follow up period in a previously "negative" athlete. Both were asymptomatic, and single photon emission tomography and/or stress echocardiography were negative for myocardial ischaemia. The athletes remained symptom-free during the period of the study. One athlete died during the follow up for coronary artery disease: he showed polymorphous ventricular tachycardia during both the exercise test and Holter monitoring, but no significant ST segment depression. Conclusions: The finding of false positive ST segment depression in elderly athletes, although still not fully understood, may be related to the physiological cardiac remodelling induced by regular training. Thus athletes with exercise induced ST segment depression, with no associated symptoms and/or complex ventricular arrhythmias, and no adverse findings at second level cardiological testing, should be considered free from coronary disease and safe to continue athletic training. PMID:16046336

  10. Repeated stress-induced expression pattern alterations of the hippocampal chloride transporters KCC2 and NKCC1 associated with behavioral abnormalities in female mice.

    PubMed

    Tsukahara, Takao; Masuhara, Masaaki; Iwai, Haruki; Sonomura, Takahiro; Sato, Tomoaki

    2015-09-11

    The balance of cation-chloride co-transporters, particularly KCC2 and NKCC1, is critical for GABAergic inhibitory signaling. However, KCC2/NKCC1 balance is disrupted in many neurodegenerative diseases. Moreover, correlations between chronic stress, KCC2 and NKCC1 in the hippocampus remain poorly understood. Despite the fact that emotional disorders in humans are far more prevalent in women, there have been relatively few studies about female subjects. Here we investigated behaviors and expression patterns of KCC2 and NKCC1 in the hippocampi of female mice under chronic stress. Repeated stress (RS) was induced in experimental mice by repeated forced water administration. Then, expression patterns of GABAergic signaling molecules were identified by immunohistochemical analysis and performance was assessed using several behavioral tests. The results of semi-quantitative analysis showed that RS decreased KCC2 expression and increased NKCC1 expression in membranes of granular and pyramidal cells in the hippocampus. The novel object recognition (NOR) test and sociability test revealed that RS induced cognitive and sociability deficits, whereas RS increased the time spent in the open arms of the elevated plus maze test and induced attention deficits in other tests. In summary, RS induced alterations in membrane KCC2/NKCC1 balance in the hippocampus of female mice, which may contribute to GABAergic disinhibition associated with cognitional, sociability and attention deficits. PMID:26239662

  11. Building neurophenomics in zebrafish: Effects of prior testing stress and test batteries.

    PubMed

    Song, Cai; Yang, Lei; Wang, JiaJia; Chen, Peirong; Li, Shaomin; Liu, Yingcong; Nguyen, Michael; Kaluyeva, Aleksandra; Kyzar, Evan J; Gaikwad, Siddharth; Kalueff, Allan V

    2016-09-15

    The zebrafish (Danio rerio) is a promising model organism for neurophenomics - a new field of neuroscience linking neural phenotypes to various genetic and environmental factors. However, the effects of prior experimental manipulations on zebrafish performance in different behavioral paradigms remain unclear. Here, we examine the influence of selected stressful procedures and test batteries on adult zebrafish anxiety-like behaviors in two commonly used models - the novel tank (NTT) and the light-dark box (LDB) tests. While no overt behavioral differences between outbred short-fin wild-type (WT) and mutant 'pink' glowfish were seen in both tests under baseline (control) conditions, an acute severe stressor (a 30-min car transportation) detected significantly lower mutant fish anxiety-like behavior in these tests. In contrast, WT zebrafish showed no overt NTT or LDB responses following a mild stressor (5-min 40-Wt light) exposure, also showing no differences in batteries of NTT and LDB run immediately one after another, or with a 1-day interval. Collectively, these findings suggest that zebrafish may be relatively less sensitive (e.g., than other popular species, such as rodents) to the test battery effect, and show that stronger stressors may be needed (to complement low-to-moderate stress aquatic screens) to better reveal phenotypical variance in zebrafish assays. Strengthening the value of zebrafish models in neurophenotyping research, this study indicates the potential of using more test batteries and a wider spectrum of pre-test stressors in zebrafish behavioral assays. PMID:27155502

  12. Building neurophenomics in zebrafish: Effects of prior testing stress and test batteries.

    PubMed

    Song, Cai; Yang, Lei; Wang, JiaJia; Chen, Peirong; Li, Shaomin; Liu, Yingcong; Nguyen, Michael; Kaluyeva, Aleksandra; Kyzar, Evan J; Gaikwad, Siddharth; Kalueff, Allan V

    2016-09-15

    The zebrafish (Danio rerio) is a promising model organism for neurophenomics - a new field of neuroscience linking neural phenotypes to various genetic and environmental factors. However, the effects of prior experimental manipulations on zebrafish performance in different behavioral paradigms remain unclear. Here, we examine the influence of selected stressful procedures and test batteries on adult zebrafish anxiety-like behaviors in two commonly used models - the novel tank (NTT) and the light-dark box (LDB) tests. While no overt behavioral differences between outbred short-fin wild-type (WT) and mutant 'pink' glowfish were seen in both tests under baseline (control) conditions, an acute severe stressor (a 30-min car transportation) detected significantly lower mutant fish anxiety-like behavior in these tests. In contrast, WT zebrafish showed no overt NTT or LDB responses following a mild stressor (5-min 40-Wt light) exposure, also showing no differences in batteries of NTT and LDB run immediately one after another, or with a 1-day interval. Collectively, these findings suggest that zebrafish may be relatively less sensitive (e.g., than other popular species, such as rodents) to the test battery effect, and show that stronger stressors may be needed (to complement low-to-moderate stress aquatic screens) to better reveal phenotypical variance in zebrafish assays. Strengthening the value of zebrafish models in neurophenotyping research, this study indicates the potential of using more test batteries and a wider spectrum of pre-test stressors in zebrafish behavioral assays.

  13. Developing Software to “Track and Catch” Missed Follow-up of Abnormal Test Results in a Complex Sociotechnical Environment

    PubMed Central

    Smith, M.; Murphy, D.; Laxmisan, A.; Sittig, D.; Reis, B.; Esquivel, A.; Singh, H.

    2013-01-01

    Summary Background Abnormal test results do not always receive timely follow-up, even when providers are notified through electronic health record (EHR)-based alerts. High workload, alert fatigue, and other demands on attention disrupt a provider’s prospective memory for tasks required to initiate follow-up. Thus, EHR-based tracking and reminding functionalities are needed to improve follow-up. Objectives The purpose of this study was to develop a decision-support software prototype enabling individual and system-wide tracking of abnormal test result alerts lacking follow-up, and to conduct formative evaluations, including usability testing. Methods We developed a working prototype software system, the Alert Watch And Response Engine (AWARE), to detect abnormal test result alerts lacking documented follow-up, and to present context-specific reminders to providers. Development and testing took place within the VA’s EHR and focused on four cancer-related abnormal test results. Design concepts emphasized mitigating the effects of high workload and alert fatigue while being minimally intrusive. We conducted a multifaceted formative evaluation of the software, addressing fit within the larger socio-technical system. Evaluations included usability testing with the prototype and interview questions about organizational and workflow factors. Participants included 23 physicians, 9 clinical information technology specialists, and 8 quality/safety managers. Results Evaluation results indicated that our software prototype fit within the technical environment and clinical workflow, and physicians were able to use it successfully. Quality/safety managers reported that the tool would be useful in future quality assurance activities to detect patients who lack documented follow-up. Additionally, we successfully installed the software on the local facility’s “test” EHR system, thus demonstrating technical compatibility. Conclusion To address the factors involved in missed

  14. Chronic agomelatine treatment corrects the abnormalities in the circadian rhythm of motor activity and sleep/wake cycle induced by prenatal restraint stress in adult rats.

    PubMed

    Mairesse, Jerome; Silletti, Viviana; Laloux, Charlotte; Zuena, Anna Rita; Giovine, Angela; Consolazione, Michol; van Camp, Gilles; Malagodi, Marithe; Gaetani, Silvana; Cianci, Silvia; Catalani, Assia; Mennuni, Gioacchino; Mazzetta, Alessandro; van Reeth, Olivier; Gabriel, Cecilia; Mocaër, Elisabeth; Nicoletti, Ferdinando; Morley-Fletcher, Sara; Maccari, Stefania

    2013-03-01

    Agomelatine is a novel antidepressant acting as an MT1/MT2 melatonin receptor agonist/5-HT2C serotonin receptor antagonist. Because of its peculiar pharmacological profile, this drug caters the potential to correct the abnormalities of circadian rhythms associated with mood disorders, including abnormalities of the sleep/wake cycle. Here, we examined the effect of chronic agomelatine treatment on sleep architecture and circadian rhythms of motor activity using the rat model of prenatal restraint stress (PRS) as a putative 'aetiological' model of depression. PRS was delivered to the mothers during the last 10 d of pregnancy. The adult progeny ('PRS rats') showed a reduced duration of slow wave sleep, an increased duration of rapid eye movement (REM) sleep, an increased number of REM sleep events and an increase in motor activity before the beginning of the dark phase of the light/dark cycle. In addition, adult PRS rats showed an increased expression of the transcript of the primary response gene, c-Fos, in the hippocampus just prior to the beginning of the dark phase. All these changes were reversed by a chronic oral treatment with agomelatine (2000 ppm in the diet). The effect of agomelatine on sleep was largely attenuated by treatment with the MT1/MT2 melatonin receptor antagonist, S22153, which caused PRS-like sleep disturbances on its own. These data provide the first evidence that agomelatine corrects sleep architecture and restores circadian homeostasis in a preclinical model of depression and supports the value of agomelatine as a novel antidepressant that resynchronizes circadian rhythms under pathological conditions.

  15. Clinical studies of the vibration syndrome using a cold stress test measuring finger temperature.

    PubMed

    Gautherie, M

    1995-01-01

    Since nine years multicentre, transversal and longitudinal clinical studies on hand-arm, vibration-exposed patients are being performed in cooperation with French occupational medicine centers and social security institutions. These studies are based upon current clinical assessment and standardized, temperature-measuring cooling tests. Data acquisition uses a portable, 10-channel, micro-processor-based temperature recorder and miniature thermal sensors. Temperature is monitored at the ten finger tips continuously, before, during and after a cold stress performed in strictly controlled conditions. Data from examinations performed at outlying sites are transferred through the telephonic network to a central processing unit. Data analysis uses a specific, expert-type software procedure based upon previous clinical studies on (i) 238 "normal" subjects, and (ii) 3,046 patients with vascular disturbances of the upper extremities of various etiologies. This procedure includes a staging process which assigns each finger a class representing the degree of severity of the abnormalities of response to cold ("dysthermia") related to vascular disorders. All data processing is fully automatic and results in a printed examination report. To date, over 1,623 vibration-exposed forestry, building and mechanical workers were examined. Sixty-three per cent of patients had received high dose of vibration (daily use of chain saws, air hammers, ballast tampers over many years). Typical white finger attacks or only neurological symptoms were found in 36% and 23% of patients respectively. The rate of sever dysthermia was much higher in patients with white finger attacks (83%) than in patients without (32%). In 90% of the vibration-exposed patients, the severity of dysthermia has differed greatly from one finger to another and between hands, while in non-exposed patients with primary Raynaud syndrome the dysthermia are generally similar for all fingers but the thumbs. Of 208 forestry

  16. EKGs and Exercise Stress Tests: When You Need Them for Heart Disease - and When You Don't

    MedlinePlus

    ... Resources EKGs and Exercise Stress Tests EKGs and Exercise Stress Tests When you need them—and when ... or electrocardiogram, measures your heart’s activity. In an exercise stress test, you have an EKG while you ...

  17. Stress and coping responses to proficiency testing in school-age children.

    PubMed

    Skybo, Theresa; Buck, Jacalyn

    2007-01-01

    Nurses encounter school-age children experiencing multiple stressors and stress symptoms. Performance on proficiency tests is viewed as stressor. The purpose of this repeated measures study was to assess 53 fourth grade children's appraisal of proficiency tests, concurrent stressors, stress symptoms, and coping strategies. During October, February, March, and April, children completed a ranking of their stress associated with proficiency testing and also reported their stressors, stress symptoms, and coping strategies. Results indicated that children appraised proficiency tests as most stressful at the beginning of the school year but less stressful at the time of the test. Stressors and stress symptoms increased from baseline to 1 month before testing then declined. The number of coping strategies used by the children decreased throughout the year. Nurses can work with parents and teachers to identify children with test anxiety and target these children for interventions to improve their coping strategies. PMID:18041329

  18. Adaptive Stress Testing of Airborne Collision Avoidance Systems

    NASA Technical Reports Server (NTRS)

    Lee, Ritchie; Kochenderfer, Mykel J.; Mengshoel, Ole J.; Brat, Guillaume P.; Owen, Michael P.

    2015-01-01

    This paper presents a scalable method to efficiently search for the most likely state trajectory leading to an event given only a simulator of a system. Our approach uses a reinforcement learning formulation and solves it using Monte Carlo Tree Search (MCTS). The approach places very few requirements on the underlying system, requiring only that the simulator provide some basic controls, the ability to evaluate certain conditions, and a mechanism to control the stochasticity in the system. Access to the system state is not required, allowing the method to support systems with hidden state. The method is applied to stress test a prototype aircraft collision avoidance system to identify trajectories that are likely to lead to near mid-air collisions. We present results for both single and multi-threat encounters and discuss their relevance. Compared with direct Monte Carlo search, this MCTS method performs significantly better both in finding events and in maximizing their likelihood.

  19. A rapid stress-corrosion test for aluminum alloys

    NASA Technical Reports Server (NTRS)

    Helfrich, W. J.

    1968-01-01

    Stressed alloy specimens are immersed in a salt-dichromate solution at 60 degrees C. Because of the minimal general corrosion of these alloys in this solution, stress corrosion failures are detected by low-power microscopic examination.

  20. Testing of Carbon Fiber Composite Overwrapped Pressure Vessel Stress-Rupture Lifetime

    NASA Technical Reports Server (NTRS)

    Grimes-Ledesma, Lorie; Phoenix, S. Leigh; Beeson, Harold; Yoder, Tommy; Greene, Nathaniel

    2006-01-01

    This paper contains summaries of testing procedures and analysis of stress rupture life testing for two stress rupture test programs, one for Kevlar COPVs performed at Lawrence Livermore National Laboratory, and the other a joint study between NASA JSC White Sands Test Facility and the Jet Propulsion Laboratory. These will be discussed in detail including test setup and issues encountered during testing. Lessons learned from testing in these two programs will be discussed.

  1. Dynamic MR imaging and stress testing in glenohumeral instability: comparison with normal shoulders and clinical/surgical findings.

    PubMed

    Hodge, D K; Beaulieu, C F; Thabit, G H; Gold, G E; Bergman, A G; Butts, R K; Dillingham, M F; Herfkens, R J

    2001-05-01

    Our objectives were to test the hypotheses that: 1) during shoulder motion, glenohumeral alignment differs between asymptomatic shoulders and those with symptomatic instability; 2) during magnetic resonance (MR)-monitored physical exam or stress testing, glenohumeral alignment differs between asymptomatic shoulders and those with instability; and 3) glenohumeral translation during MR stress testing correlates with findings of shoulder instability by clinical exam and exam under anesthesia (EUA). Using an open-configuration 0.5 T MR imaging (MRI) system, we studied symptomatic shoulders in 11 subjects and compared them to their contralateral asymptomatic shoulders. Each shoulder was studied during abduction/adduction and internal/external rotation to determine the humeral head position on the glenoid. An examiner also performed the MR stress test on each shoulder by applying manual force on the humeral head during imaging. All shoulders were assigned an instability grade from the MR stress test, and this grade was correlated with: 1) clinical exam grade assigned during preoperative assessment by an orthopedic surgeon and 2) intraoperative instability grade by EUA immediately preceding arthroscopy. With dynamic abduction and internal/external rotation, the humeral head remained centered on the glenoid in 9 of 11 shoulders, but in two subjects there were dramatic demonstrations of subluxation. With stress testing, a trend toward more joint laxity was demonstrated in symptomatic than in asymptomatic joints (P = 0.11). MR grading of instability correlated directly with clinical grading in six cases and underestimated the degree of instability relative to clinical exam in the other cases. MR instability grading systematically underestimated instability compared with EUA in 7 of the 10 cases that underwent surgical repair. We concluded that dynamic MR evaluation of glenohumeral alignment did not demonstrate abnormalities in symptomatic shoulders in 8 of 10 patients

  2. Expanding stress generation theory: test of a transdiagnostic model.

    PubMed

    Conway, Christopher C; Hammen, Constance; Brennan, Patricia A

    2012-08-01

    Originally formulated to understand the recurrence of depressive disorders, the stress generation hypothesis has recently been applied in research on anxiety and externalizing disorders. Results from these investigations, in combination with findings of extensive comorbidity between depression and other mental disorders, suggest the need for an expansion of stress generation models to include the stress generating effects of transdiagnostic pathology as well as those of specific syndromes. Employing latent variable modeling techniques to parse the general and specific elements of commonly co-occurring Axis I syndromes, the current study examined the associations of transdiagnostic internalizing and externalizing dimensions with stressful life events over time. Analyses revealed that, after adjusting for the covariation between the dimensions, internalizing was a significant predictor of interpersonal dependent stress, whereas externalizing was a significant predictor of noninterpersonal dependent stress. Neither latent dimension was associated with the occurrence of independent, or fateful, stressful life events. At the syndrome level, once variance due to the internalizing factor was partialed out, unipolar depression contributed incrementally to the generation of interpersonal dependent stress. In contrast, the presence of panic disorder produced a "stress inhibition" effect, predicting reduced exposure to interpersonal dependent stress. Additionally, dysthymia was associated with an excess of noninterpersonal dependent stress. The latent variable modeling framework used here is discussed in terms of its potential as an integrative model for stress generation research.

  3. Direct test of static stress versus dynamic stress triggering of aftershocks

    USGS Publications Warehouse

    Pollitz, F.F.; Johnston, M.J.S.

    2006-01-01

    Aftershocks observed over time scales of minutes to months following a main shock are plausibly triggered by the static stress change imparted by the main shock, dynamic shaking effects associated with passage of seismic waves from the main shock, or a combination of the two. We design a direct test of static versus dynamic triggering of aftershocks by comparing the near-field temporal aftershock patterns generated by aseismic and impulsive events occurring in the same source area. The San Juan Bautista, California, area is ideally suited for this purpose because several events of both types of M???5 have occurred since 1974. We find that aftershock rates observed after impulsive events are much higher than those observed after aseismic events, and this pattern persists for several weeks after the event. This suggests that, at least in the near field, dynamic triggering is the dominant cause of aftershocks, and that it generates both immediate and delayed aftershock activity.

  4. Acceleration of degradation by highly accelerated stress test and air-included highly accelerated stress test in crystalline silicon photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Suzuki, Soh; Tanahashi, Tadanori; Doi, Takuya; Masuda, Atsushi

    2016-02-01

    We examined the effects of hyper-hygrothermal stresses with or without air on the degradation of crystalline silicon (c-Si) photovoltaic (PV) modules, to shorten the required duration of a conventional hygrothermal-stress test [i.e., the “damp heat (DH) stress test”, which is conducted at 85 °C/85% relative humidity for 1,000 h]. Interestingly, the encapsulant within a PV module becomes discolored under the air-included hygrothermal conditions achieved using DH stress test equipment and an air-included highly accelerated stress test (air-HAST) apparatus, but not under the air-excluded hygrothermal conditions realized using a highly accelerated stress test (HAST) machine. In contrast, the reduction in the output power of the PV module is accelerated irrespective of air inclusion in hyper-hygrothermal test atmosphere. From these findings, we conclude that the required duration of the DH stress test will at least be significantly shortened using air-HAST, but not HAST.

  5. Disparity between online and offline tests in accelerated aging tests of LED lamps under electric stress.

    PubMed

    Wang, Yao; Jing, Lei; Ke, Hong-Liang; Hao, Jian; Gao, Qun; Wang, Xiao-Xun; Sun, Qiang; Xu, Zhi-Jun

    2016-09-20

    The accelerated aging tests under electric stress for one type of LED lamp are conducted, and the differences between online and offline tests of the degradation of luminous flux are studied in this paper. The transformation of the two test modes is achieved with an adjustable AC voltage stabilized power source. Experimental results show that the exponential fitting of the luminous flux degradation in online tests possesses a higher fitting degree for most lamps, and the degradation rate of the luminous flux by online tests is always lower than that by offline tests. Bayes estimation and Weibull distribution are used to calculate the failure probabilities under the accelerated voltages, and then the reliability of the lamps under rated voltage of 220 V is estimated by use of the inverse power law model. Results show that the relative error of the lifetime estimation by offline tests increases as the failure probability decreases, and it cannot be neglected when the failure probability is less than 1%. The relative errors of lifetime estimation are 7.9%, 5.8%, 4.2%, and 3.5%, at the failure probabilities of 0.1%, 1%, 5%, and 10%, respectively. PMID:27661576

  6. Dobutamine stress echo is superior to exercise stress testing in achieving target heart rate among patients on beta blockers.

    PubMed

    Sabbath, Adam; Pack, Michael; Markiewicz, Richard; John, Jooby; Gaballa, Mohamed; Goldman, Steven; Thai, Hoang

    2005-01-01

    Published guidelines recommend continuing beta-adrenergic receptor blockade in patients undergoing stress testing. We evaluated the role of pharmacological versus exercise stress testing in achieving target heart rate (THR) among patients on beta-adrenergic blockade. We compared data from 140 patients who underwent dobutamine stress echo (DSE) and 143 patients who underwent exercise treadmill testing (ETT). In both groups, beta-adrenergic blocker was continued at the time of stress testing. Overall, patients undergoing DSE achieved THR more frequently than ETT. With beta-adrenergic blockade, DSE patients met THR more frequently than ETT patients (p < 0.001). Without beta-adrenergic blockade, there was no difference between either modality in achieving THR. In both DSE and ETT patients, absence of beta-adrenergic blockade increased the odds of achieving THR [odds ratio (OR): 2.46, p = 0.042 and OR: 7.44, p < 0.001, respectively]. Atropine use with DSE increased the odds of achieving THR (OR: 3.76, p = 0.006). In conclusion, pharmacological stress testing appears to be superior to exercise stress testing in achieving THR among patients on beta-adrenergic blockade.

  7. A new diagnostic workflow for patients with mental retardation and/or multiple congenital abnormalities: test arrays first.

    PubMed

    Gijsbers, Antoinet C J; Lew, Janet Y K; Bosch, Cathy A J; Schuurs-Hoeijmakers, Janneke H M; van Haeringen, Arie; den Hollander, Nicolette S; Kant, Sarina G; Bijlsma, Emilia K; Breuning, Martijn H; Bakker, Egbert; Ruivenkamp, Claudia A L

    2009-11-01

    High-density single-nucleotide polymorphism (SNP) genotyping technology enables extensive genotyping as well as the detection of increasingly smaller chromosomal aberrations. In this study, we assess molecular karyotyping as first-round analysis of patients with mental retardation and/or multiple congenital abnormalities (MR/MCA). We used different commercially available SNP array platforms, the Affymetrix GeneChip 262K NspI, the Genechip 238K StyI, the Illumina HumanHap 300 and HumanCNV 370 BeadChip, to detect copy number variants (CNVs) in 318 patients with unexplained MR/MCA. We found abnormalities in 22.6% of the patients, including six CNVs that overlap known microdeletion/duplication syndromes, eight CNVs that overlap recently described syndromes, 63 potentially pathogenic CNVs (in 52 patients), four large segments of homozygosity and two mosaic trisomies for an entire chromosome. This study shows that high-density SNP array analysis reveals a much higher diagnostic yield as that of conventional karyotyping. SNP arrays have the potential to detect CNVs, mosaics, uniparental disomies and loss of heterozygosity in one experiment. We, therefore, propose a novel diagnostic approach to all MR/MCA patients by first analyzing every patient with an SNP array instead of conventional karyotyping.

  8. Cerium migration during PEM fuel cell accelerated stress testing

    SciTech Connect

    Baker, Andrew M.; Mukundan, Rangachary; Borup, Rodney L.; Spernjak, Dusan; Judge, Elizabeth J.; Advani, Suresh G.; Prasad, Ajay K.

    2016-01-01

    Cerium is a radical scavenger which improves polymer electrolyte membrane (PEM) fuel cell durability. During operation, however, cerium rapidly migrates in the PEM and into the catalyst layers (CLs). In this work, membrane electrode assemblies (MEAs) were subjected to accelerated stress tests (ASTs) under different humidity conditions. Cerium migration was characterized in the MEAs after ASTs using X-ray fluorescence. During fully humidified operation, water flux from cell inlet to outlet generated in-plane cerium gradients. Conversely, cerium profiles were flat during low humidity operation, where in-plane water flux was negligible, however, migration from the PEM into the CLs was enhanced. Humidity cycling resulted in both in-plane cerium gradients due to water flux during the hydration component of the cycle, and significant migration into the CLs. Fluoride and cerium emissions into effluent cell waters were measured during ASTs and correlated, which signifies that ionomer degradation products serve as possible counter-ions for cerium emissions. Fluoride emission rates were also correlated to final PEM cerium contents, which indicates that PEM degradation and cerium migration are coupled. Lastly, it is proposed that cerium migrates from the PEM due to humidification conditions and degradation, and is subsequently stabilized in the CLs by carbon catalyst supports.

  9. Cerium migration during PEM fuel cell accelerated stress testing

    DOE PAGES

    Baker, Andrew M.; Mukundan, Rangachary; Borup, Rodney L.; Spernjak, Dusan; Judge, Elizabeth J.; Advani, Suresh G.; Prasad, Ajay K.

    2016-01-01

    Cerium is a radical scavenger which improves polymer electrolyte membrane (PEM) fuel cell durability. During operation, however, cerium rapidly migrates in the PEM and into the catalyst layers (CLs). In this work, membrane electrode assemblies (MEAs) were subjected to accelerated stress tests (ASTs) under different humidity conditions. Cerium migration was characterized in the MEAs after ASTs using X-ray fluorescence. During fully humidified operation, water flux from cell inlet to outlet generated in-plane cerium gradients. Conversely, cerium profiles were flat during low humidity operation, where in-plane water flux was negligible, however, migration from the PEM into the CLs was enhanced. Humiditymore » cycling resulted in both in-plane cerium gradients due to water flux during the hydration component of the cycle, and significant migration into the CLs. Fluoride and cerium emissions into effluent cell waters were measured during ASTs and correlated, which signifies that ionomer degradation products serve as possible counter-ions for cerium emissions. Fluoride emission rates were also correlated to final PEM cerium contents, which indicates that PEM degradation and cerium migration are coupled. Lastly, it is proposed that cerium migrates from the PEM due to humidification conditions and degradation, and is subsequently stabilized in the CLs by carbon catalyst supports.« less

  10. Examination of the "specimen-size-effect" in stress-corrosion-cracking (SCC) tests

    NASA Astrophysics Data System (ADS)

    Semerad, E.; Dunn, B. D.

    2003-09-01

    The effect of the specimen's size on the determination of susceptibility to SCC is investigated by a series of SCC-tests. Parameter variations considered were in particular two types of material grades, two stress levels (75% and 50% of the 0.2% proof stress) and, most important, two specimens sizes, i.e. standard turned stress-corrosion test specimens (according to ECSS) and miniature size test specimens (according to ASTM).

  11. 12 CFR Appendix A to Subpart B of... - Risk-Based Capital Stress Test

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Risk-Based Capital Stress Test A Appendix A to... Appendix A to Subpart B of Part 652— Risk-Based Capital Stress Test 2.0 Credit Risk. 2.1 Loss-Frequency and... Volume. 2.5 Calculation of Loss Rates for Use in the Stress Test for All Types of Loans, Except...

  12. 12 CFR Appendix A to Subpart B of... - Risk-Based Capital Stress Test

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Risk-Based Capital Stress Test A Appendix A to... Appendix A to Subpart B of Part 652— Risk-Based Capital Stress Test 2.0Credit Risk. 2.1Loss-Frequency and... Volume. 2.5Calculation of Loss Rates for Use in the Stress Test for All Types of Loans, Except...

  13. 12 CFR Appendix A to Subpart B of... - Risk-Based Capital Stress Test

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Risk-Based Capital Stress Test A Appendix A to... Appendix A to Subpart B of Part 652— Risk-Based Capital Stress Test 2.0Credit Risk. 2.1Loss-Frequency and... Volume. 2.5Calculation of Loss Rates for Use in the Stress Test for All Types of Loans, Except...

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

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  15. Determination of in situ state of stress at the Spent Fuel Test-Climax site, Climax Stock, Nevada Test Site

    USGS Publications Warehouse

    Ellis, W.L.; Magner, J.E.

    1982-01-01

    Determination of the in situ state of stress at the site of the Spent Fuel Test--Climax, using the U.S. Bureau of Mines overcore method, indicates principal stress magnitudes of 11.6 MPa, 7.1 MPa, and 2.8 MPa. The bearing and plunge of the maximum and minimum principal stress components are, respectively: N. 56? E., 29? NE; and N. 42? W., 14? NW. The vertical stress magnitude of 7.9 MPa calculated from the overcore data is significantly less than expected from overburden pressure, suggesting the stress field is influenced by local or areal geologic factors. Results from this investigation indicate (1) the stress state at the Spent Fuel Test--Climax site deviates significantly from a gravitational stress field, both in relative stress magnitudes and in orientation; (2) numerical modeling will not realistically simulate the near-field response of the Spent Fuel Test--Climax site if gravitational and (or) horizontal and vertical applied stress boundary conditions are assumed; and (3) substantial stress variations may occur spatially within the stock.

  16. 77 FR 68047 - Policy Statement on the Principles for Development and Distribution of Annual Stress Test Scenarios

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-15

    ... based on the annual stress test cycle set out in Table 1. \\1\\ 77 FR 61238 (October 9, 2012). Table 1... scenarios for covered institutions. \\1\\ Annual Stress Test, 77 FR 61238 (October 9, 2012). II. STRESS TESTS... of Annual Stress Test Scenarios AGENCY: Office of the Comptroller of the Currency (OCC),...

  17. The probability for a Pap test to be abnormal is directly proportional to HPV viral load: results from a Swiss study comparing HPV testing and liquid-based cytology to detect cervical cancer precursors in 13,842 women.

    PubMed

    Bigras, G; de Marval, F

    2005-09-01

    In a study involving 13,842 women and 113 gynaecologists, liquid-based cytology and HPV testing for detecting cervical cancer were compared. A total of 1334 women were found to be positive for one or both tests and were invited for colposcopy with biopsy. A total of 1031 satisfactory biopsies on 1031 women were thereafter collected using a systematic biopsy protocol, which was random in the colposcopically normal-appearing cervix or directed in the abnormal one. In all, 502 women with negative tests were also biopsied. A total of 82 histologic high-grade squamous intraepithelial lesion (HSIL) were reported in biopsies, all from the group with one or both tests positive. Sensitivity and specificity to detect histologic HSIL were 59 and 97% for cytology, and 97 and 92% for HPV. In total, 14% of reviewed negative cytological preparations associated with histologic HSIL contained no morphologically abnormal cells despite a positive HPV test. This suggested a theoretical limit for cytology sensitivity. HPV viral load analysis of the 1143 HPV-positive samples showed a direct relationship between abnormal Pap test frequency and HPV viral load. Thus, not only does the HPV testing have a greater sensitivity than cytology but the probability of the latter being positive can also be defined as a function of the associated HPV viral load. PMID:16136031

  18. The probability for a Pap test to be abnormal is directly proportional to HPV viral load: results from a Swiss study comparing HPV testing and liquid-based cytology to detect cervical cancer precursors in 13 842 women

    PubMed Central

    Bigras, G; de Marval, F

    2005-01-01

    In a study involving 13 842 women and 113 gynaecologists, liquid-based cytology and HPV testing for detecting cervical cancer were compared. A total of 1334 women were found to be positive for one or both tests and were invited for colposcopy with biopsy. A total of 1031 satisfactory biopsies on 1031 women were thereafter collected using a systematic biopsy protocol, which was random in the colposcopically normal-appearing cervix or directed in the abnormal one. In all, 502 women with negative tests were also biopsied. A total of 82 histologic high-grade squamous intraepithelial lesion (HSIL) were reported in biopsies, all from the group with one or both tests positive. Sensitivity and specificity to detect histologic HSIL were 59 and 97% for cytology, and 97 and 92% for HPV. In total, 14% of reviewed negative cytological preparations associated with histologic HSIL contained no morphologically abnormal cells despite a positive HPV test. This suggested a theoretical limit for cytology sensitivity. HPV viral load analysis of the 1143 HPV-positive samples showed a direct relationship between abnormal Pap test frequency and HPV viral load. Thus, not only does the HPV testing have a greater sensitivity than cytology but the probability of the latter being positive can also be defined as a function of the associated HPV viral load. PMID:16136031

  19. High-Stakes Testing and Its Relationship to Stress Levels of Coastal Secondary Teachers

    ERIC Educational Resources Information Center

    McDaniel, Sheneatha Lashelle Alexander

    2012-01-01

    The purpose of this research was to examine the relationship between high-stakes tests and stress with secondary teachers. Furthermore, this study investigated whether veteran teachers experience more stress than novice teachers and whether or not self-efficacy, gender, accountability status, and years of experience influence teacher stress as it…

  20. Help-Seeking Decisions of Battered Women: A Test of Learned Helplessness and Two Stress Theories.

    ERIC Educational Resources Information Center

    Wauchope, Barbara A.

    This study tested the learned helplessness theory, stress theory, and a modified stress theory to determine the best model for predicting the probability that a woman would seek help when she experienced severe violence from a male partner. The probability was hypothesized to increase as the stress of the violence experienced increased. Data were…

  1. Parent and Adolescent Responses to Poverty Related Stress: Tests of Mediated and Moderated Coping Models

    ERIC Educational Resources Information Center

    Wadsworth, Martha E.; Raviv, Tali; Compas, Bruce E.; Connor-Smith, Jennifer K.

    2005-01-01

    We tested several models of the associations among economic strain, life stress, coping, involuntary stress responses, and psychological symptoms in a sample of 57 parent-adolescent dyads from rural, lower-income families. Economic strain and life stress predicted symptoms for both parents and adolescents. Stressor-symptom specificity was found…

  2. Using Uncertainty Analysis to Guide the Development of Accelerated Stress Tests (Presentation)

    SciTech Connect

    Kempe, M.

    2014-03-01

    Extrapolation of accelerated testing to the long-term results expected in the field has uncertainty associated with the acceleration factors and the range of possible stresses in the field. When multiple stresses (such as temperature and humidity) can be used to increase the acceleration, the uncertainty may be reduced according to which stress factors are used to accelerate the degradation.

  3. Coronary Disease in Emergency Department Chest Pain Patients with Recent Negative Stress Testing

    PubMed Central

    Walker, Jonathan; Galuska, Michael; Vega, David

    2010-01-01

    Background: Cardiac stress tests for diagnosis of coronary artery disease (CAD) are incompletely sensitive and specific. Objective: We examined the frequency of significant CAD in patients presenting to the emergency department (ED) with chest pain who have had a recent negative or inconclusive (<85% of predicted maximum heart rate) cardiac stress test. Methods: This was a retrospective chart review of patients identified from ED and cardiology registries at the study hospital. We included patients presenting to the ED with a chief complaint of chest pain, with a negative cardiac stress test in the past three years as the last cardiac test, and hospital admission. One-hundred sixty-four patients met the inclusion criteria. Their admission was reviewed for diagnosis of CAD by positive serum troponin, percutaneous coronary intervention, or positive stress test while an inpatient. Results: Of 164 patients, 122(74.4%, 95% CI 67.7, 81.1) had a negative stress test prior to the index admission, while 42 (25.6%, 95% CI 18.9, 32.3) had otherwise normal but inconclusive stress tests. Thirty-four (20.7%, 95% CI 14.4,27.0) of the included patients were determined to have CAD. Twenty-five of the 122 patients (20.5%, 95% CI 13.3, 27.7) had negative pre-admission stress tests and nine of 42 patients (21.4%, 95% CI 9.0, 33.8) had inclusive stress tests of CAD. A statistical comparison between these two proportions showed no significant difference (p = .973). Conclusion: Due to inadequate sensitivity, negative non-invasive cardiac stress tests should not be used to rule out CAD. Patients with negative stress tests are just as likely to have CAD as patients with inconclusive stress tests. PMID:21079714

  4. Diagnostic value of fasting capillary glucose, fructosamine and glycosylated haemoglobin in detecting diabetes and other glucose tolerance abnormalities compared to oral glucose tolerance test.

    PubMed

    Herdzik, E; Safranow, K; Ciechanowski, K

    2002-04-01

    New diagnostic criteria for diabetes mellitus recommend lowering of the fasting plasma glucose to 7.0 mmol/l. In contrast to recommendations of the American Diabetes Association (ADA), WHO recommends using the oral glucose tolerance test (OGTT) in clinical practice. In this study. based on OGTT results and WHO 1998 criteria, we determined if measuring fasting capillary glycaemia (FCG) along with fructosamine and/or glycosylated haemoglobin allows the detection of glucose tolerance abnormalities better than FCG alone. OGTT was performed in 538 patients. Serum fructosamine was determined in 480 of the patients, and glycosylated haemoglobin in 234 of the patients. According to WHO 1998 criteria, the patients were divided into groups due to glucose tolerance abnormalities. Fructosamine correlated stronger with 2-h post-load glucose concentrations than with FCG. HbAlc correlated stronger with FCG than with 2-h post-load glucose. Combined use of fructosamine and FCG predicted 2-h post-load glucose better than combined use of FCG and HbA1c. Receiver operating characteristic curve analyses showed that FCG was the best criterion in discriminating diabetes. Combined use of FCG and fructosamine slightly improved the ability to discriminate glucose tolerance abnormalities from normal glucose tolerance. FCG is the most effective predictor of 2-h post-load glucose and the best criterion for discriminating diabetes and other glucose tolerance abnormalities from normal glucose tolerance. Fructosamine is a potentially useful post-load glycaemia index. OGTT is irreplaceable in identification of patients with high post-load glycaemia.

  5. Nondestructive testing and characterization of residual stress field using an ultrasonic method

    NASA Astrophysics Data System (ADS)

    Song, Wentao; Xu, Chunguang; Pan, Qinxue; Song, Jianfeng

    2016-03-01

    To address the difficulty in testing and calibrating the stress gradient in the depth direction of mechanical components, a new technology of nondestructive testing and characterization of the residual stress gradient field by ultrasonic method is proposed based on acoustoelasticity theory. By carrying out theoretical analysis, the sensitivity coefficients of different types of ultrasonic are obtained by taking the low carbon steel(12%C) as a research object. By fixing the interval distance between sending and receiving transducers, the mathematical expressions of the change of stress and the variation of time are established. To design one sending-one receiving and oblique incidence ultrasonic detection probes, according to Snell law, the critically refracted longitudinal wave (LCR wave) is excited at a certain depth of the fixed distance of the tested components. Then, the relationship between the depth of LCR wave detection and the center frequency of the probe in Q235 steel is obtained through experimental study. To detect the stress gradient in the depth direction, a stress gradient LCR wave detection model is established, through which the stress gradient formula is derived by the relationship between center frequency and detecting depth. A C-shaped stress specimen of Q235 steel is designed to conduct stress loading tests, and the stress is measured with the five group probes at different center frequencies. The accuracy of ultrasonic testing is verified by X-ray stress analyzer. The stress value of each specific depth is calculated using the stress gradient formula. Accordingly, the ultrasonic characterization of residual stress field is realized. Characterization results show that the stress gradient distribution is consistent with the simulation in ANSYS. The new technology can be widely applied in the detection of the residual stress gradient field caused by mechanical processing, such as welding and shot peening.

  6. MRI findings in throwing shoulders: abnormalities in professional handball players.

    PubMed

    Jost, Bernhard; Zumstein, Matthias; Pfirrmann, Christian W A; Zanetti, Marco; Gerber, Christian

    2005-05-01

    Shoulders of throwing athletes are highly stressed joints and likely to have more structural abnormalities seen on magnetic resonance imaging scans. Prevalence and type of structural abnormalities, especially abnormalities of the rotator cuff tendons and the superolateral humeral head, and correlation of magnetic resonance imaging findings with symptoms and clinical tests, are not well known. Throwing and nonthrowing (symptomatic and asymptomatic) shoulders of 30 fully competitive professional handball players and 20 dominant shoulders of randomly selected volunteers were evaluated for comparison clinically and with magnetic resonance imaging. An average of seven abnormal magnetic resonance imaging findings was observed in the throwing shoulders; more than in the nonthrowing and the control shoulders. Although 93% of the throwing shoulders had abnormal magnetic resonance imaging findings, only 37% were symptomatic. Partial rotator cuff tears and mainly superolateral osteochondral defects of the humeral head were identified as typical throwing lesions. Symptoms correlated poorly with abnormalities seen on magnetic resonance imaging scans and findings from clinical tests. This suggests that the evaluation of an athlete's throwing shoulder should be done very thoroughly and should not be based mainly on abnormalities seen on magnetic resonance imaging scans.

  7. Effects of sleep deprivation on behaviors and abnormal hippocampal BDNF/miR-10B expression in rats with chronic stress depression

    PubMed Central

    Jiang, Yuxue; Zhu, Jinfu

    2015-01-01

    Being sleep-deprived can relieve the depressed emotions in rats, but the underlying mechanisms remain unknown. In this study, male rats were divided into 3 groups: normal control (NC), chronicunpredictable stress (CUPS) and sleep-deprived (SD). All of the groups were examined using the sucrose consumption test and the open field test. The sucrose consumption test and the open field test were performed for all three groups. The BDNF and miR-10B expressions were examined using real-time PCR and the level of BNDF was discovered by western blotting. In the sucrose consumption test and the open field test, the CUPS rats consumed less sucrose and got fewer score than the NC rats, however the SD rats consumed significantly more sucrose and received higher scores than the CUPS rats. Both the expression of BNDF and the protein levels in the CUPS group was significantly lower than in the NC group. Also, the CUPS group also showed a higher miR-10B expression than the NC group. However, the SD group demonstrated higher BDNF expression and lower miR-10B expression when compared with the CUPS group. Further investigation demonstrated that the BDNF is the direct target gene of miR-10B and BDNF expression, which is negatively correlated with the expression of miR-10B. In the sucrose consumption test, BNDF expression is positively correlated with the sucrose preference rate whereas miR-10B has an opposing correlation. Moreover, the open field test demonstrated that BNDF expression is positively correlated with the scores and the miR-10B expression is negatively correlated. These results indicate that sleep deprivation is closely linked with the downregulation of miR-10B and possibly the upregulation of BDNF in the hippocampus in the CUPS rats. PMID:25755749

  8. Stress corrosion evaluation of powder metallurgy aluminum alloy 7091 with the breaking load test method

    NASA Technical Reports Server (NTRS)

    Domack, Marcia S.

    1987-01-01

    The stress corrosion behavior of the P/M aluminum alloy 7091 is evaluated in two overaged heat treatment conditions, T7E69 and T7E70, using an accelerated test technique known as the breaking load test method. The breaking load data obtained in this study indicate that P/M 7091 alloy is highly resistant to stress corrosion in both longitudinal and transverse orientations at stress levels up to 90 percent of the material yield strength. The reduction in mean breaking stress as a result of corrosive attack is smallest for the more overaged T7E70 condition. Details of the test procedure are included.

  9. Effects of stress rate and calculation method on subcritical crack growth parameters deduced from constant stress-rate flexural testing

    PubMed Central

    Griggs, Jason A.; Alaqeel, Samer M.; Zhang, Yunlong; Miller, Amp W.; Cai, Zhuo

    2011-01-01

    Objectives To more efficiently determine the subcritical crack growth (SCG) parameters of dental ceramics, the effects of stressing rate and choice of statistical regression model on estimates of SCG parameters were assessed. Methods Two dental ceramic materials, a veneering material having a single critical flaw population (S) and a framework material having partially concurrent flaw populations (PC), were analyzed using constant stress-rate testing, or “dynamic fatigue”, with a variety of testing protocols. For each material, 150 rectangular beam specimens were prepared and tested in four-point flexure according to ISO6872 and ASTM1368. A full-factorial study was conducted on the following factors: material, stress rate assumed vs. calculated, number of stress rates, and statistical regression method. Results The proportion of specimens for which the statistical models over-estimated reliability was not significantly different based on regression method for Material S (P = 0.96, power = 94%) and was significantly different based on regression method for Material PC (P < 0.001). The standard method resulted in SCG parameters, n and ln B, of 35.9 and -11.1 MPa2s for Material S and 12.4 and 9.61 MPa2s for Material PC. Significance The method of calculation that uses only the median strength value at each stress rate provided the most robust SCG parameter estimates. Using only two stress rates resulted in fatigue parameters comparable to those estimated using four stress rates having the same range. The stress rate of each specimen can be assumed to be the target stress rate with negligible difference in SCG parameter estimates. PMID:21167586

  10. Bending fatigue tests on SiC-Al tapes under alternating stress at room temperature

    NASA Technical Reports Server (NTRS)

    Herzog, J. A.

    1981-01-01

    The development of a testing method for fatigue tests on SiC-Al tapes containing a small amount of SiC filaments under alternating stress is reported. The fatigue strength curves resulting for this composite are discussed. They permit an estimate of its behavior under continuous stress and in combination with various other matrices, especially metal matrices.

  11. Study made of procedures for externally loading and corrosion testing stress corrosion specimens

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1967-01-01

    Study was initiated to determine methods or test specimens for evaluating stress corrosion cracking characteristics of common structural materials. It was found that the methods of externally loading and corrosion testing were reliable in yielding reproducible results for stress corrosion evaluation.

  12. Stress test: identifying crowding stress-tolerant hybrids in processing sweet corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvement in tolerance to intense competition at high plant populations (i.e. crowding stress) is a major genetic driver of corn yield gain the last half-century. Recent research found differences in crowding stress tolerance among a few modern processing sweet corn hybrids; however, a larger asse...

  13. 78 FR 64153 - Policy Statement on the Principles for Development and Distribution of Annual Stress Test Scenarios

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-28

    ... based on the annual stress test cycle set out in Table 1. \\2\\ 77 FR 61238 (October 9, 2012). Table 1..., 77 FR 52792, 52796, n.11 (Aug. 30, 2012). The commenter also believed that stress testing models... scenarios for covered institutions. \\1\\ Annual Stress Test, 77 FR 61238 (October 9, 2012). II. Stress...

  14. 77 FR 69553 - Policy Statement on the Principles for Development and Distribution of Annual Stress Test Scenarios

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-20

    ... published in the Federal Register on October 15, 2012 (77 FR 62417), the Stress Test Rule implementing the... banks. \\1\\ 77 FR 62417 (Oct. 15, 2012). II. Stress Tests As defined by the Stress Test Rule, a stress... no later than November 15th of each year. \\1\\ 77 FR 62417 (Oct. 15, 2012). DATES: This...

  15. [Unpredictable chronic mild stress effects on antidepressants activities in forced swim test].

    PubMed

    Kudryashov, N V; Kalinina, T S; Voronina, T A

    2015-02-01

    The experiments has been designed to study unpredictable chronic mild stress effect on anti-depressive activities of amitriptyline (10 mg/kg) and fluoxetine (20 mg/kg) in forced swim test in male outbred mice. It is shown that acute treatment with fluoxetine does not produce any antidepressant effects in mice following stress of 14 days while the sub-chronic injections of fluoxetine result in more deep depressive-like behavior. In 28 daily stressed mice, antidepressant effect of fluoxetine is observed independently of the injection rates. Amitriptyline demonstrates the antidepressant activity regardless of the duration of stress or administration scheduling, but at the same time the severity of anti-immobilization effect of amitriptyline in stressed mice is weaker in compare to non-stressed trails. Thus, the injection rates and duration of unpredictable mild chronic stress are the parameters that determine the efficiency of antidepressants in the mouse forced swimming test.

  16. The Effect of Stress and Recovery on Field-test Performance in Floorball.

    PubMed

    van der Does, H T D; Brink, M S; Visscher, C; Huijgen, B C H; Frencken, W G P; Lemmink, K A P M

    2015-06-01

    Physical and psychosocial stress and recovery are important performance determinants. A holistic approach that monitors these performance determinants over a longer period of time is lacking. Therefore this study aims to investigate the effect of a player's physical and psychosocial stress and recovery on field-test performance. In a prospective non-experimental cohort design 10 female Dutch floorball players were monitored over 6 months. To monitor physical and psychosocial stress and recovery, daily training-logs and 3-weekly the Recovery-Stress Questionnaire for Athletes (RESTQ-Sport) were filled out respectively. To determine field-test performance 6 Heart rate Interval Monitoring System (HIMS) and 4 Repeated Modified Agility T-test (RMAT) measurements were performed. Multilevel prediction models were applied to account for within-players and between-players field-test performance changes. The results show that more psychosocial stress and less psychosocial recovery over 3-6 weeks before testing decrease HIMS performance (p≤0.05). More physical stress over 6 weeks before testing improves RMAT performance (p≤0.05). In conclusion, physical and psychosocial stress and recovery affect submaximal interval-based running performance and agility up to 6 weeks before testing. Therefore both physical and psychosocial stress and recovery should be monitored in daily routines to optimize performance.

  17. Combination of physico-chemical analysis, Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay/nuclear abnormalities tests for cyto-genotoxicity assessments of treated effluents discharged from textile industries.

    PubMed

    Hemachandra, Chamini K; Pathiratne, Asoka

    2016-09-01

    Bioassays for cyto-genotoxicity assessments are generally not required in current textile industry effluent discharge management regulations. The present study applied in vivo plant and fish based toxicity tests viz. Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay and nuclear abnormalities tests in combination with physico-chemical analysis for assessing potential cytotoxic/genotoxic impacts of treated textile industry effluents reaching a major river (Kelani River) in Sri Lanka. Of the treated effluents tested from two textile industries, color in the Textile industry 1 effluents occasionally and color, biochemical oxygen demand and chemical oxygen demand in the Textile industry 2 effluents frequently exceeded the specified Sri Lankan tolerance limits for discharge of industrial effluents into inland surface waters. Exposure of A. cepa bulbs to 100% and 12.5% treated effluents from both industries resulted in statistically significant root growth retardation, mito-depression, and induction of chromosomal abnormalities in root meristematic cells in comparison to the dilution water in all cases demonstrating cyto-genotoxicity associated with the treated effluents. Exposure of O. niloticus to the 100% and 12.5% effluents, resulted in erythrocytic genetic damage as shown by elevated total comet scores and induction of nuclear abnormalities confirming the genotoxicity of the treated effluents even with 1:8 dilution. The results provide strong scientific evidence for the crucial necessity of incorporating cyto-genotoxicity impact assessment tools in textile industry effluent management regulations considering human health and ecological health of the receiving water course under chronic exposure.

  18. De-Stressing High-Stakes Testing for NCLB

    ERIC Educational Resources Information Center

    Fedore, Heidi

    2006-01-01

    It is readily apparent that testing raises academic standards at both the state and the federal levels. The three Rs currently touted as aims for school improvement--rigor, relevance, and relationships--can be applied to testing as well. The connection between standardized testing and rigor can be easily made, while the relevance of testing is…

  19. The effectiveness of the Uchida-Kraepelin test for psychological stress: an analysis of plasma and salivary stress substances

    PubMed Central

    Sugimoto, Koreaki; Kanai, Aya; Shoji, Noriaki

    2009-01-01

    Background The hypothalamic-pituitary-adrenocortical (HPA) axis and sympathetic adrenomedullary (SAM) system are the major stress-response pathways. Plasma adrenocorticotropic hormone (ACTH) represents HPA axis activity, while plasma catecholamines are used as markers of the SAM system. Salivary alpha amylase (AA), chromogranin A (CgA), and immunoglobulin A (IgA) are candidate markers of stress activation, although their role has not been established. The Uchida-Kraepelin (U-K) test is a questionnaire that requires intense concentration and effort, and has been used as a tool to induce mental stress. However, it is not clear whether or not the test is effective as a psychological/mental stressor. Methods In this study, normal young women took the U-K test and serial measurements of plasma ACTH and catecholamines (dopamine, noradrenaline, and adrenaline) (n = 10), as well as salivary AA, CgA, and IgA (n = 16) before, during and after the test. Results We found no changes in any of these parameters at any time point during or after the U-K test. Conclusion Our findings indicate that the U-K test is not a suitable for measuring the psychological/mental stress of young women because the plasma data showed that it did not affect the HPA axis and SAM system. The U-K test should be employed carefully as a psychological/mental stressor due to insufficient scientific evidence of its effectiveness. In addition, salivary AA, CgA, and IgA should not simply be compared with previous reports, because the mechanism of secretion and normal range of each salivary parameter remain unknown. Salivary AA, CgA, and IgA may not be suitable candidate markers of psychological/mental stress. PMID:19341484

  20. Accelerated and environmental module stress testing at NREL

    SciTech Connect

    Osterwald, C.R.; Basso, T.S.; del Cueto, J.A.; McMahon, T.J.; Pruett, J.; Trudell, D.

    1999-03-01

    This paper presents an overview of the Module Testing and Technology Validation task at the National Renewable Energy Laboratory. The extensive module testing capabilities at the Outdoor Test Facility are outlined, emphasizing the test facilities, equipment, and analytical services available. Highlights and results of several recent testing efforts are then presented, followed by a list of the external programs supported by the task. The paper concludes with a brief description of the new testing programs that are planned for the near future. {copyright} {ital 1999 American Institute of Physics.}

  1. Transistor step stress testing program for JANTX2N2905A

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The effect of power/temperature step stress when applied to the transistor JANTX2N2905A manufactured by Texas Instruments and Motorola is reported. A total of 48 samples from each manufacturer was submitted to the process outlined. In addition, two control sample units were maintained for verification of the electrical parametric testing. All test samples were subjected to the electrical tests outlined in Table 2 after completing the prior power/temperature step stress point.

  2. Detecting Visual Function Abnormality with a Contrast-Dependent Visual Test in Patients with Type 2 Diabetes

    PubMed Central

    Jang, Yuh; Hu, Fu-Chang; Wu, Wei-Chi

    2016-01-01

    In addition to diabetic retinopathy, diabetes also causes early retinal neurodegeneration and other eye problems, which cause various types of visual deficits. This study used a computer-based visual test (Macular Multi-Function Assessment (MMFA)) to assess contrast-dependent macular visual function in patients with type 2 diabetes to collect more visual information than possible with only the visual acuity test. Because the MMFA is a newly developed test, this study first compared the agreement and discriminative ability of the MMFA and the Early Treatment Diabetic Retinopathy Study (ETDRS) contrast acuity charts. Then symbol discrimination performances of diabetic patients and controls were evaluated at 4 contrast levels using the MMFA. Seventy-seven patients and 45 controls participated. The agreement between MMFA and ETDRS scores was examined by fitting three-level linear mixed-effect models to estimate the intraclass correlation coefficients (ICCs). The estimated areas under the receiver operating characteristic (ROC) curve were used to compare the discriminative ability of diseased versus non-diseased participants between the two tests. The MMFA scores of patients and controls were compared with multiple linear regression analysis after adjusting the effects of age, sex, hypertension and cataract. Results showed that the scores of the MMFA and ETDRS tests displayed high levels of agreement and acceptable and similar discriminative ability. The MMFA performance was correlated with the severity of diabetic retinopathy. Most of the MMFA scores differed significantly between the diabetic patients and controls. In the low contrast condition, the MMFA scores were significantly lower for 006Eon-DR patients than for controls. The potential utility of the MMFA as an easy screening tool for contrast-dependent visual function and for detecting early functional visual change in patients with type 2 diabetes is discussed. PMID:27611680

  3. Detecting Visual Function Abnormality with a Contrast-Dependent Visual Test in Patients with Type 2 Diabetes.

    PubMed

    Tsai, Li-Ting; Liao, Kuo-Meng; Jang, Yuh; Hu, Fu-Chang; Wu, Wei-Chi

    2016-01-01

    In addition to diabetic retinopathy, diabetes also causes early retinal neurodegeneration and other eye problems, which cause various types of visual deficits. This study used a computer-based visual test (Macular Multi-Function Assessment (MMFA)) to assess contrast-dependent macular visual function in patients with type 2 diabetes to collect more visual information than possible with only the visual acuity test. Because the MMFA is a newly developed test, this study first compared the agreement and discriminative ability of the MMFA and the Early Treatment Diabetic Retinopathy Study (ETDRS) contrast acuity charts. Then symbol discrimination performances of diabetic patients and controls were evaluated at 4 contrast levels using the MMFA. Seventy-seven patients and 45 controls participated. The agreement between MMFA and ETDRS scores was examined by fitting three-level linear mixed-effect models to estimate the intraclass correlation coefficients (ICCs). The estimated areas under the receiver operating characteristic (ROC) curve were used to compare the discriminative ability of diseased versus non-diseased participants between the two tests. The MMFA scores of patients and controls were compared with multiple linear regression analysis after adjusting the effects of age, sex, hypertension and cataract. Results showed that the scores of the MMFA and ETDRS tests displayed high levels of agreement and acceptable and similar discriminative ability. The MMFA performance was correlated with the severity of diabetic retinopathy. Most of the MMFA scores differed significantly between the diabetic patients and controls. In the low contrast condition, the MMFA scores were significantly lower for 006Eon-DR patients than for controls. The potential utility of the MMFA as an easy screening tool for contrast-dependent visual function and for detecting early functional visual change in patients with type 2 diabetes is discussed. PMID:27611680

  4. The association of clinical indication for exercise stress testing with all-cause mortality: the FIT Project

    PubMed Central

    Kim, Joonseok; Al-Mallah, Mouaz; Juraschek, Stephen P.; Brawner, Clinton; Keteyian, Steve J.; Nasir, Khurram; Dardari, Zeina A.; Blumenthal, Roger S.

    2016-01-01

    Introduction We hypothesized that the indication for stress testing provided by the referring physician would be an independent predictor of all-cause mortality. Material and methods We studied 48,914 patients from The Henry Ford Exercise Testing Project (The FIT Project) without known congestive heart failure who were referred for a clinical treadmill stress test and followed for 11 ±4.7 years. The reason for stress test referral was abstracted from the clinical test order, and should be considered the primary concerning symptom or indication as stated by the ordering clinician. Hierarchical multivariable Cox proportional hazards regression was performed, after controlling for potential confounders including demographics, risk factors, and medication use as well as additional adjustment for exercise capacity in the final model. Results A total of 67% of the patients were referred for chest pain, 12% for shortness of breath (SOB), 4% for palpitations, 3% for pre-operative evaluation, 6% for abnormal prior testing, and 7% for risk factors only. There were 6,211 total deaths during follow-up. Compared to chest pain, those referred for palpitations (HR = 0.72, 95% CI: 0.60–0.86) and risk factors only (HR = 0.72, 95% CI: 0.63–0.82) had a lower risk of all-cause mortality, whereas those referred for SOB (HR = 1.15, 95% CI: 1.07–1.23) and pre-operative evaluation (HR = 2.11, 95% CI: 1.94–2.30) had an increased risk. In subgroup analysis, referral for palpitations was protective only in those without coronary artery disease (CAD) (HR = 0.75, 95% CI: 0.62–0.90), while SOB increased mortality risk only in those with established CAD (HR = 1.25, 95% CI: 1.10–1.44). Conclusions The indication for stress testing is an independent predictor of mortality, showing an interaction with CAD status. Importantly, SOB may be associated with higher mortality risk than chest pain, particularly in patients with CAD. PMID:27186173

  5. The Application of Normal Stress Reduction Function in Tilt Tests for Different Block Shapes

    NASA Astrophysics Data System (ADS)

    Kim, Dong Hyun; Gratchev, Ivan; Hein, Maw; Balasubramaniam, Arumugam

    2016-08-01

    This paper focuses on the influence of the shapes of rock cores, which control the sliding or toppling behaviours in tilt tests for the estimation of rock joint roughness coefficients (JRC). When the JRC values are estimated by performing tilt tests, the values are directly proportional to the basic friction of the rock material and the applied normal stress on the sliding planes. Normal stress obviously varies with the shape of the sliding block, and the basic friction angle is also affected by the sample shapes in tilt tests. In this study, the shapes of core blocks are classified into three representative shapes and those are created using plaster. Using the various shaped artificial cores, a set of tilt tests is carried out to identify the shape influences on the normal stress and the basic friction angle in tilt tests. The test results propose a normal stress reduction function to estimate the normal stress for tilt tests according to the sample shapes based on Barton's empirical equation. The proposed normal stress reduction functions are verified by tilt tests using artificial plaster joints and real rock joint sets. The plaster joint sets are well matched and cast in detailed printed moulds using a 3D printing technique. With the application of the functions, the obtained JRC values from the tilt tests using the plaster samples and the natural rock samples are distributed within a reasonable JRC range when compared with the measured values.

  6. Assessment of abnormal blood flow and efficacy of treatment in patients with systemic sclerosis using a newly developed microwireless laser Doppler flowmeter and arm-raising test.

    PubMed

    Kido, M; Takeuchi, S; Hayashida, S; Urabe, K; Sawada, R; Furue, M

    2007-10-01

    Background Patients with systemic sclerosis (SSc) frequently suffer from recalcitrant digital ulceration because of impaired cutaneous blood flow (CBF). A simple and accurate CBF measurement would be helpful to evaluate the disease status and efficacy of treatment in such patients. Objectives To examine the feasibility of a newly developed, micromachined integrated laser blood flowmeter (MILBF) for evaluation of abnormal CBF responses in patients with SSc. Methods CBF of finger pulp was measured in eight patients with SSc and in six healthy controls using MILBF. CBF in the steady state and the responses to the arm-raising test and cold provocation were assessed. The therapeutic efficacy of a single and an intensive prostaglandin E(1) (PGE(1)) infusion treatment was also evaluated in some of the SSc patients. Results The patients with SSc showed significantly lower steady-state CBF than controls. The rate of blood flow with cold provocation and the velocity of blood flow recovery after cold provocation (VR-CP) tended to be lower in patients with SSc. Augmentation of amplitude of the digital pulse wave by arm raising (AA-AR) was observed in controls, but not in patients with SSc. We also found that VR-CP and AA-AR may be good markers for evaluating the efficacy of vasodilatory treatment. It should be noted that the examined patients did not complain of any pain and/or distress during the arm-raising test, as opposed to during cold provocation. Conclusions CBF assessment using MILBF and an arm-raising test is accurate, noninvasive and well tolerated and thus the combination may be a better alternative method to evaluate abnormal CBF and efficacy of treatment in patients with SSc.

  7. Rethinking innovative designs to further test parasite-stress theory.

    PubMed

    Uskul, Ayse K

    2012-04-01

    Fincher & Thornhill's (F&T's) parasite-stress theory of sociality is supported largely by correlational evidence; its persuasiveness would increase significantly via lab and natural experiments and demonstrations of its mediating role. How the theory is linked to other approaches to group differences in psychological differences and to production and dissemination of cultural ideas and practices, need further clarification. So does the theory's view on the possible reduction of negative group interactions.

  8. Standardized fluorescence in situ hybridization testing based on an appropriate panel of probes more effectively identifies common cytogenetic abnormalities in myelodysplastic syndromes than conventional cytogenetic analysis: a multicenter prospective study of 2302 patients in China.

    PubMed

    Lai, Yue-Yun; Huang, Xiao-Jun; Li, Juan; Zou, Ping; Xu, Ze-Feng; Sun, Hui; Shao, Zong-Hong; Zhou, Dao-Bin; Chen, Fang-Ping; Liu, Zhuo-Gang; Zhu, Huan-Ling; Wu, De-Pei; Wang, Chun; Zhang, Yin; Li, Yan; Hou, Ming; Du, Xin; Wang, Xin; Li, Wei; Lai, Yong-Rong; Zhou, Jin; Zhou, Yu-Hong; Fang, Mei-Yun; Qiu, Lin; Wang, Xiao-Min; Zhang, Guang-Sen; Jiang, Ming; Liang, Ying-Min; Zhang, Lian-Sheng; Chen, Xie-Qun; Bai, Hai; Lin, Jin-Ying

    2015-05-01

    In an attempt to establish the advantages of fluorescence in situ hybridization (FISH) studies over conventional cytogenetic (CC) analysis, a total of 2302 de novo MDS patients from 31 Chinese institutions were prospectively selected in the present study for both CC and standardized FISH analysis for +8, -7/7q-, -5/5q-, 20q- and-Y chromosomal abnormalities. CC analysis was successful in 94.0% of the patients; of these patients, 35.9% of the cases were abnormal. FISH analysis was successful in all 2302 patients and detected at least one type of common cytogenetic abnormality in 42.7% of the cases. The incidences of +8, -7/7q-, -5/5q-, 20q- and-Y chromosomal abnormalities by FISH were 4.1% to 8.7% higher than those by CC. FISH identified abnormalities in 23.6% of the patients exhibiting normal CC results and revealed that 20.7% of the patients with adequate normal metaphases (≥20) had abnormal clones. FISH identified cytogenetic abnormalities in 50.4% of the patients with failed CC analysis. In summary, our multicenter studies emphasised and confirmed the importance of applying standardized FISH testing based on an appropriate panel of probes to detect common cytogenetic abnormalities in Chinese de novo MDS patients, particularly those with normal or failed CC results.

  9. Electrocardiographic markers of ischemia during mental stress testing in postinfarction patients. Role of body surface mapping

    SciTech Connect

    Bosimini, E.; Galli, M.; Guagliumi, G.; Giubbini, R.; Tavazzi, L. )

    1991-04-01

    In patients with coronary artery disease, radionuclide investigations have documented a high incidence of mental stress-induced myocardial ischemia in the absence of significant electrocardiographic changes and/or angina. To investigate the causes of the low electrocardiographic sensitivity, we recorded body surface maps during mental arithmetic in 22 normal volunteers and 37 postinfarction patients with residual exercise ischemia. Myocardial perfusion was studied with thallium-201 or technetium-99 (SESTAMIBI) planar scans. In 14 patients, body surface maps were also recorded during atrial pacing at the heart rate values achieved during mental stress. While taking the body surface maps, the area from J point to 80 msec after this point (ST-80) was analyzed by integral maps, difference maps, and departure maps. The body surface mapping criteria for ischemia were a new negative area on the integral maps, a negative potential of more than 2 SD from mean normal values on the difference maps, and a negative departure index of more than 2. Scintigraphy showed asymptomatic myocardial hypoperfusion in 33 patients. Eight patients had significant ST segment depression. The ST-80 integral and difference maps identified 17 ischemic patients. Twenty-four patients presented abnormal departure maps. One patient presented ST depression and abnormal body surface maps without reversible tracer defect. In 14 of 14 patients, atrial pacing did not reproduce the body surface map abnormalities. The analyses of the other electrocardiographic variables showed that in patients with mental stress-induced perfusion defects, only changes of T apex-T offset (aT-eT) interval in Frank leads and changes of maximum negative potential value of aT-eT integral maps significantly differed from those of normal subjects.

  10. The 'Trier Social Stress Test'--a tool for investigating psychobiological stress responses in a laboratory setting.

    PubMed

    Kirschbaum, C; Pirke, K M; Hellhammer, D H

    1993-01-01

    This paper describes a protocol for induction of moderate psychological stress in a laboratory setting and evaluates its effects on physiological responses. The 'Trier Social Stress Test' (TSST) mainly consists of an anticipation period (10 min) and a test period (10 min) in which the subjects have to deliver a free speech and perform mental arithmetic in front of an audience. In six independent studies this protocol has been found to induce considerable changes in the concentration of ACTH, cortisol (serum and saliva), GH, prolactin as well as significant increases in heart rate. As for salivary cortisol levels, the TSST reliably led to 2- to 4-fold elevations above baseline with similar peak cortisol concentrations. Studies are summarized in which TSST-induced cortisol increases elucidated some of the multiple variables contributing to the interindividual variation in adrenocortical stress responses. The results suggest that gender, genetics and nicotine consumption can influence the individual's stress responsiveness to psychological stress while personality traits showed no correlation with cortisol responses to TSST stimulation. From these data we conclude that the TSST can serve as a tool for psychobiological research. PMID:8255414

  11. Experimenter Effects on Cardiovascular Reactivity and Task Performance during Mental Stress Testing

    ERIC Educational Resources Information Center

    Siegwarth, Nicole; Larkin, Kevin T.; Kemmner, Christine

    2012-01-01

    Experimenter effects have long been hypothesized to influence participants' responses to mental stress testing. To explore the influence of experimenter warmth on responses to two mental stress tasks (mental arithmetic, mirror tracing), 32 young women participated in a single 45-min experimental session. Participants were randomized into warm…

  12. Social Support for Divorced Fathers' Parenting: Testing a Stress-Buffering Model

    ERIC Educational Resources Information Center

    DeGarmo, David S.; Patras, Joshua; Eap, Sopagna

    2008-01-01

    A stress-buffering hypothesis for parenting was tested in a county-representative sample of 218 divorced fathers. Social support for parenting (emergency and nonemergency child care, practical support, financial support) was hypothesized to moderate effects of stress (role overload, coparental conflict, and daily hassles) on fathers' quality…

  13. Visual Stress Theory and Its Application to Reading and Reading Tests

    ERIC Educational Resources Information Center

    Wilkins, Arnold; Huang, Jie; Cao, Yue

    2004-01-01

    This paper presents a theory of visual stress. The theory is applied to the assessment of symptoms of visual stress and its treatment with coloured filters. The theory has implications for standard reading assessments that relate both to the visual skills and the age of the children taking the tests. These implications are reviewed, with the…

  14. [Early stress tests following an uncomplicated myocardial infarct: a comparison between symptom-limited and submaximal tests].

    PubMed

    López, J; Carrasco, H A; Portillo, S; Maldonado, Z; Monzón de Briceño, Y

    1991-01-01

    To compare the diagnostic and prognostic usefulness of symptom-limited versus load-limited submaximal stress testing, 76 patients, during the first week post acute non-complicated myocardial infarction, were submitted to a symptom-limited Naughton-modified protocol stress test. At 2 METs, 3 METs and maximal effort levels, the tests were classified as positive or negative following the currently used criteria. After a mean follow-up of 15 months, the symptom-limited protocol showed the best sensitivity (95%), specificity (78%), positive (64%) and negative (98%) predictive value, and also the highest risk ratio (27.4) for prediction of subsequent coronary events (2p less than 0.01 vs 2 METs, 3 METs and 2D-Echocardiogram results). Forward stepped multiple correlation analysis indicated independent prognostic value for the results of the symptom-limited stress test (R2: .52 p less than 0.01) and for the location of the myocardial infarction (R2: .05 p less than 0.05) only. In addition, the discriminant prognostic power of the symptom-limited protocol was significant after the fourth month of follow-up (2p less than 0.05 vs submaximal tests and 2D-Echo). Therefore, we recommend the performance of a symptom-limited stress test during the first week post acute non-complicated myocardial infarction, provided that all coronary active medication has been withheld 24 hours before the test.

  15. Testing the responses of four wheat crop models to heat stress at anthesis and grain filling.

    PubMed

    Liu, Bing; Asseng, Senthold; Liu, Leilei; Tang, Liang; Cao, Weixing; Zhu, Yan

    2016-05-01

    Higher temperatures caused by future climate change will bring more frequent heat stress events and pose an increasing risk to global wheat production. Crop models have been widely used to simulate future crop productivity but are rarely tested with observed heat stress experimental datasets. Four wheat models (DSSAT-CERES-Wheat, DSSAT-Nwheat, APSIM-Wheat, and WheatGrow) were evaluated with 4 years of environment-controlled phytotron experimental datasets with two wheat cultivars under heat stress at anthesis and grain filling stages. Heat stress at anthesis reduced observed grain numbers per unit area and individual grain size, while heat stress during grain filling mainly decreased the size of the individual grains. The observed impact of heat stress on grain filling duration, total aboveground biomass, grain yield, and grain protein concentration (GPC) varied depending on cultivar and accumulated heat stress. For every unit increase of heat degree days (HDD, degree days over 30 °C), grain filling duration was reduced by 0.30-0.60%, total aboveground biomass was reduced by 0.37-0.43%, and grain yield was reduced by 1.0-1.6%, but GPC was increased by 0.50% for cv Yangmai16 and 0.80% for cv Xumai30. The tested crop simulation models could reproduce some of the observed reductions in grain filling duration, final total aboveground biomass, and grain yield, as well as the observed increase in GPC due to heat stress. Most of the crop models tended to reproduce heat stress impacts better during grain filling than at anthesis. Some of the tested models require improvements in the response to heat stress during grain filling, but all models need improvements in simulating heat stress effects on grain set during anthesis. The observed significant genetic variability in the response of wheat to heat stress needs to be considered through cultivar parameters in future simulation studies.

  16. Optical diagnostic test of stress conditions of aquatic organisms.

    PubMed

    Axenov-Gribanov, Denis V; Gurkov, Anton N; Shakhtanova, Nadezhda S; Bedulina, Daria S; Timofeyev, Maxim A; Meglinski, Igor

    2011-09-01

    Global climate change has become a dire reality and its impact is expected to rise dramatically in the near future. Combined with the day-to-day human activities the climatic changes heavily affect the environment. In particular, a global temperature increase accompanied by a number of anthropogenic chemicals falling within the freshwater ecosystem results in a dramatic enhancement of the overall stress for most aquatic organisms. This leads to a significant shift in the species inventory and potential breakdown of the water ecosystem with severe consequences for local economies and water supply. In order to understand and predict the influence of climatic changes on the physiological and biochemical processes that take place in living aquatic organisms we explore the application of optical spectroscopy for monitoring and quantitative assessment of antioxidant enzymes activity in benthic amphipods of Lake Baikal. We demonstrate that the changes of the enzymes activity in Baikal amphipods undergoing thermal and/or hypoxia stress can be observed and documented by UV and optical spectroscopy both in vivo and in vitro. PMID:21548104

  17. Application of iChemExplorer in pharmaceutical pH stress testing.

    PubMed

    Qiu, Fenghe; Du, Lily; Soman, Ashish; Jankovsky, Corinne; Li, Chan

    2013-03-25

    pH stress testing is an integral part of pharmaceutical stress testing and is a regulatory requirement for validating a stability indicating analytical method and elucidating degradation products and degradation pathways. This paper reports the results of an evaluation of iChemExplorer (ICE) for drug substance and drug product pH stress testing in comparison with the conventional (manual) approach. ICE is a simple and inexpensive technology, and through real case studies it was demonstrated that ICE is an efficient and "fit-for-purpose" alternative in conducting pharmaceutical pH stress testing. In addition, when using a non-isothermal ICE protocol, it is feasible to estimate the pH degradation kinetics (e.g., E(a)) using the ICE software. PMID:23339989

  18. In-situ stress from hydraulic fracture measurements in G Tunnel, Nevada Test Site

    SciTech Connect

    Smith, C.; Vollendorf, W. C.; Warren, W. E.

    1981-04-01

    Hydraulic fracture work in G Tunnel, Nevada Test Site, performed to obtain the in-situ stress state is discussed. Field equipment and procedures are described; analysis is developed to relate the hydraulic fracture pressures to the in-situ stress state. Pressure data are analyzed to provide estimates of the stress state at a number of locations in the tunnel complex. A unique feature of the work is the mineback - a mining process in which the rock is cut away to reveal the actual plane of the fracture. Advantages, limitations, and problem areas associated with extracting in-situ stress fields from hydraulic fracture pressure records are discussed in detail.

  19. Characterization of Min-K TE-1400 Thermal Insulation (Two-Year Gradient Stress Relaxation Testing Update)

    SciTech Connect

    Hemrick, James Gordon; Lara-Curzio, Edgar; King, James

    2009-09-01

    Min-K 1400TE insulation material was characterized at Oak Ridge National Laboratory for use in structural applications under gradient temperature conditions. A previous report (ORNL/TM-2008/089) discusses the testing and results from the original three year duration of the project. This testing included compression testing to determine the effect of sample size and test specimen geometry on the compressive strength of Min-K, subsequent compression testing on cylindrical specimens to determine loading rates for stress relaxation testing, isothermal stress relaxation testing, and gradient stress relaxation testing. This report presents the results from the continuation of the gradient temperature stress relaxation testing and the resulting updated modeling.

  20. Transistor step stress testing program for JANTX2N2369A

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The effect is reported of power/temperature step stress when applied to the transistor JANTX2N2369A manufactured by Raytheon and National Semiconductor. A total of 48 samples from each manufacturer was submitted to the process. In addition, two control sample units were maintained for verification of the electrical parametric testing. The power/thermal stress tests are described, and failure analyses are presented.

  1. An Automatic System of Testing the Best Stress of Installation for Semiconductor Refrigeration Piece

    NASA Astrophysics Data System (ADS)

    Chen, Hongyan; Song, Ping

    Concerning the problems of the impact on the factors of installation about semiconductor refrigeration piece are rarely studied in China and abroad, a reasonable structure of test device is designed, using stepper motor to test the temperature of the cold surface under different stress of installation to get the best stress of installation for the semiconductor refrigeration piece. Experiments shows that the system is of good noise immunity, high controlling and measuring precision.

  2. A simple osmotic stress test to predict boar sperm cryosurvival.

    PubMed

    Garzon-Perez, Cesar; Flores, Hector F; Medrano, Alfredo

    2010-01-01

    This work was carried out to test whether viability of pig spermatozoa subjected to an osmotic test is correlated to sperm cryosurvival. Spermatozoa were cooled from 22 degrees C to -5 degrees C, aliquots were exposed to a series of hyperosmotic solutions (300-2100 mOsm/kg) for 15 min, immediately spermatozoa were re-warmed to 37 degrees C and isosmolarity was restored. Spermatozoa were cooled from 22 degrees C to -5 degrees C and one aliquot was exposed to the osmotic test while diluted spermatozoa were frozen-thawed. Plasma membrane-intact spermatozoa decreased as osmolarity increased (P < 0.0001), a further decreased (P < 0.0001) was observed when isotonicity was restored. Proportions of plasma membrane-intact and acrosome-intact cells from the osmotic test were no different from those after freeze-thawing: 36% vs. 35%, 80% vs. 80%, respectively. A significant correlation was found between the proportion of acrosome-intact cells after freeze-thawing and that from the osmotic test (r = 0.81, P <0.01). This test provides a useful and economical mean to predict in vitro boar sperm cryosurvival.

  3. Downstream Procedures and Outcomes After Stress Testing For Suspected Coronary Artery Disease in the United States

    PubMed Central

    Mudrick, Daniel W; Cowper, Patricia A; Shah, Bimal R; Patel, Manesh R; Jensen, Neil C; Drawz, Matthew J; Peterson, Eric D; Douglas, Pamela S

    2013-01-01

    Background Millions of Americans with suspected coronary artery disease undergo non-invasive cardiac stress testing annually. Downstream procedures and subsequent outcomes among symptomatic patients without known coronary disease referred for stress testing are not well characterized in contemporary community practice. Methods We examined administrative insurance billing data from a national insurance provider from November 2004 through June 2007. After excluding patients with prior cardiac disease or chest pain evaluation, we identified 80,676 people age 40–64 years with outpatient cardiac stress testing within 30 days after an office visit for chest pain. We evaluated rates of invasive coronary angiography, coronary revascularization, and cardiovascular events after stress testing. Results Within 60 days, only 8.8% of stress test patients underwent cardiac catheterization and only 2.7% underwent revascularization; within one year only 0.5% suffered death, myocardial infarction, or stroke. There were marked geographic variations in one-year rates of catheterization (3.8–14.8%) and revascularization (1.2–3.0%) across 20 hospital referral regions. Conclusions In this large national cohort of middle-aged patients without previously coded cardiac diagnosis who were referred for stress testing after outpatient chest pain evaluation, few proceeded to invasive angiography or revascularization, and subsequent cardiovascular events were infrequent. PMID:22424017

  4. Stress transfer of a Kevlar 49 fiber pullout test studied by micro-Raman spectroscopy.

    PubMed

    Lei, Zhenkun; Wang, Quan; Qiu, Wei

    2013-06-01

    The interfacial stress transfer behavior of a Kevlar 49 aramid fiber-epoxy matrix was studied with fiber pullout tests, the fibers of which were stretched by a homemade microloading device. Raman spectra on the embedded fiber were recorded by micro-Raman spectroscopy, under different strain levels. Then, the fiber axial stress was obtained by the relationship between the stress and Raman shift of the aramid fiber. Experimental results revealed that the fiber axial stress increased significantly with the load. The shear stress concentration occurred at the fiber entry to the epoxy resin. Thus, interfacial friction stages exist in the debonded fiber segment, and the interfacial friction shear stress is constant within one stage. The experimental results are consistent with the theoretical model predictions.

  5. Reduced fitness and abnormal cardiopulmonary responses to maximal exercise testing in children and young adults with sickle cell anemia.

    PubMed

    Liem, Robert I; Reddy, Madhuri; Pelligra, Stephanie A; Savant, Adrienne P; Fernhall, Bo; Rodeghier, Mark; Thompson, Alexis A

    2015-04-01

    Physiologic contributors to reduced exercise capacity in individuals with sickle cell anemia (SCA) are not well understood. The objective of this study was to characterize the cardiopulmonary response to maximal cardiopulmonary exercise testing (CPET) and determine factors associated with reduced exercise capacity among children and young adults with SCA. A cross-sectional cohort of 60 children and young adults (mean 15.1 ± 3.4 years) with hemoglobin SS or S/β(0) thalassemia and 30 matched controls (mean 14.6 ± 3.5 years) without SCA or sickle cell trait underwent maximal CPET by a graded, symptom-limited cycle ergometry protocol with breath-by-breath, gas exchange analysis. Compared to controls without SCA, subjects with SCA demonstrated significantly lower peak VO2 (26.9 ± 6.9 vs. 37.0 ± 9.2 mL/kg/min, P < 0.001). Subjects demonstrated slower oxygen uptake (ΔVO2/ΔWR, 9 ± 2 vs. 12 ± 2 mL/min/watt, P < 0.001) and lower oxygen pulse (ΔVO2/ΔHR, 12 ± 4 vs. 20 ± 7 mL/beat, P < 0.001) as well as reduced oxygen uptake efficiency (ΔVE/ΔVO2, 42 ± 8 vs. 32 ± 5, P < 0.001) and ventilation efficiency (ΔVE/ΔVCO2, 30.3 ± 3.7 vs. 27.3 ± 2.5, P < 0.001) during CPET. Peak VO2 remained significantly lower in subjects with SCA after adjusting for age, sex, body mass index (BMI), and hemoglobin, which were independent predictors of peak VO2 for subjects with SCA. In the largest study to date using maximal CPET in SCA, we demonstrate that children and young adults with SCA have reduced exercise capacity attributable to factors independent of anemia. Complex derangements in gas exchange and oxygen uptake during maximal exercise are common in this population.

  6. [Biomechanical test study of rat femurs growing under different stress environment].

    PubMed

    Liu, Yingxi; Zhao, Wenzhi; Zhang, Jun; Li, Shouju; Li, Jingnian; Sun, Xiaojiang

    2005-06-01

    By creating two kinds of stress environment in the same animal model, we performed a three-point bending test and a compressing test on the rat femurs growing under different stress conditions to characterize the effect of stress on bone mechanical properties. The right hindlimbs were subjected to sciatic nerve resection to become cripple and were used as unloading group; the left hindlimbs bore excess load and made up the overloading group; the normal rats were used as control group. The animals were encouraged to exercise for half an hour everyday in the morning, noon and evening. The experiment observation finished in four weeks. The biomechanical parameters of femur diaphyses were measured. The experiment results showed that stress environment may change several mechanical parameters of rat femurs. This study indicated that bone tissues can adapt to its stress environment by changing its mechanical properties. The experimental model in this article is practical and reliable.

  7. Combination of physico-chemical analysis, Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay/nuclear abnormalities tests for cyto-genotoxicity assessments of treated effluents discharged from textile industries.

    PubMed

    Hemachandra, Chamini K; Pathiratne, Asoka

    2016-09-01

    Bioassays for cyto-genotoxicity assessments are generally not required in current textile industry effluent discharge management regulations. The present study applied in vivo plant and fish based toxicity tests viz. Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay and nuclear abnormalities tests in combination with physico-chemical analysis for assessing potential cytotoxic/genotoxic impacts of treated textile industry effluents reaching a major river (Kelani River) in Sri Lanka. Of the treated effluents tested from two textile industries, color in the Textile industry 1 effluents occasionally and color, biochemical oxygen demand and chemical oxygen demand in the Textile industry 2 effluents frequently exceeded the specified Sri Lankan tolerance limits for discharge of industrial effluents into inland surface waters. Exposure of A. cepa bulbs to 100% and 12.5% treated effluents from both industries resulted in statistically significant root growth retardation, mito-depression, and induction of chromosomal abnormalities in root meristematic cells in comparison to the dilution water in all cases demonstrating cyto-genotoxicity associated with the treated effluents. Exposure of O. niloticus to the 100% and 12.5% effluents, resulted in erythrocytic genetic damage as shown by elevated total comet scores and induction of nuclear abnormalities confirming the genotoxicity of the treated effluents even with 1:8 dilution. The results provide strong scientific evidence for the crucial necessity of incorporating cyto-genotoxicity impact assessment tools in textile industry effluent management regulations considering human health and ecological health of the receiving water course under chronic exposure. PMID:27209118

  8. 78 FR 78694 - Orders: Supplemental Orders on Reporting by Regulated Entities of Stress Testing Results as of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-27

    ... AGENCY 12 CFR Part 1238 Orders: Supplemental Orders on Reporting by Regulated Entities of Stress Testing... additional appendices of scenario assumptions to be used for stress testing. II. Orders For the convenience... 2013-OR-FHLMC-3 SUPPLEMENTAL ORDER ON REPORTING BY REGULATED ENTITIES OF STRESS TESTING RESULTS AS...

  9. A continuous damage model based on stepwise-stress creep rupture tests

    NASA Technical Reports Server (NTRS)

    Robinson, D. N.

    1985-01-01

    A creep damage accumulation model is presented that makes use of the Kachanov damage rate concept with a provision accounting for damage that results from a variable stress history. This is accomplished through the introduction of an additional term in the Kachanov rate equation that is linear in the stress rate. Specification of the material functions and parameters in the model requires two types of constituting a data base: (1) standard constant-stress creep rupture tests, and (2) a sequence of two-step creep rupture tests.

  10. Spatial and temporal task characteristics as stress: a test of the dynamic adaptability theory of stress, workload, and performance.

    PubMed

    Szalma, James L; Teo, Grace W L

    2012-03-01

    The goal for this study was to test assertions of the dynamic adaptability theory of stress, which proposes two fundamental task dimensions, information rate (temporal properties of a task) and information structure (spatial properties of a task). The theory predicts adaptive stability across stress magnitudes, with progressive and precipitous changes in adaptive response manifesting first as increases in perceived workload and stress and then as performance failure. Information structure was manipulated by varying the number of displays to be monitored (1, 2, 4 or 8 displays). Information rate was manipulated by varying stimulus presentation rate (8, 12, 16, or 20 events/min). A signal detection task was used in which critical signals were pairs of digits that differed by 0 or 1. Performance accuracy declined and workload and stress increased as a function of increased task demand, with a precipitous decline in accuracy at the highest demand levels. However, the form of performance change as well as the pattern of relationships between speed and accuracy and between performance and workload/stress indicates that some aspects of the theory need revision. Implications of the results for the theory and for future research are discussed.

  11. Effect of Mindfulness Meditation on Perceived Stress Scores and Autonomic Function Tests of Pregnant Indian Women

    PubMed Central

    Jain, Reena; Kohli, Sangeeta; Batra, Swaraj

    2016-01-01

    Introduction Various pregnancy complications like hypertension, preeclampsia have been strongly correlated with maternal stress. One of the connecting links between pregnancy complications and maternal stress is mind-body intervention which can be part of Complementary and Alternative Medicine (CAM). Biologic measures of stress during pregnancy may get reduced by such interventions. Aim To evaluate the effect of Mindfulness meditation on perceived stress scores and autonomic function tests of pregnant Indian women. Materials and Methods Pregnant Indian women of 12 weeks gestation were randomised to two treatment groups: Test group with Mindfulness meditation and control group with their usual obstetric care. The effect of Mindfulness meditation on perceived stress scores and cardiac sympathetic functions and parasympathetic functions (Heart rate variation with respiration, lying to standing ratio, standing to lying ratio and respiratory rate) were evaluated on pregnant Indian women. Results There was a significant decrease in perceived stress scores, a significant decrease of blood pressure response to cold pressor test and a significant increase in heart rate variability in the test group (p< 0.05, significant) which indicates that mindfulness meditation is a powerful modulator of the sympathetic nervous system and can thereby reduce the day-to-day perceived stress in pregnant women. Conclusion The results of this study suggest that mindfulness meditation improves parasympathetic functions in pregnant women and is a powerful modulator of the sympathetic nervous system during pregnancy. PMID:27190795

  12. Effect of grease type on abnormal vibration of ball bearing

    NASA Astrophysics Data System (ADS)

    Itagaki, Takayoshi; Ohta, Hiroyuki; Igarashib, Teruo

    2003-12-01

    The abnormal vibration of ball bearings lubricated with grease was studied. The test bearings were lubricated with three types of grease: Li soap/silicone oil grease, Na soap/mineral oil grease and Li soap/mineral oil grease. In the experiments, the axial-loaded ball bearings were operated at a constant rotational speed, and the vibration and the outer ring temperatures of the test bearings were measured. In addition, the shear stress and shear rate of the greases were measured by a rheometer. The experimental results showed that the abnormal vibration occurs on the test bearings lubricated with all three types of grease. Based on the experimental results, the generating mechanisms of the abnormal vibrations were discussed. From the discussions, it seems reasonable to conclude: (1) Li soap/silicone oil grease and Na soap/mineral oil grease both have a negative damping moment characteristic. The abnormal vibrations of the ball bearings lubricated with these greases are generated by the negative damping moment. (2) The abnormal vibration of the ball bearings lubricated with Li soap/mineral oil grease is generated by the decreasing positive damping moment of the grease due to the rising temperature.

  13. Bayesian Analysis of Step-Stress Accelerated Life Test with Exponential Distribution

    SciTech Connect

    Lee, J.; Pan, R.

    2012-04-01

    In this article, we propose a general Bayesian inference approach to the step-stress accelerated life test with type II censoring. We assume that the failure times at each stress level are exponentially distributed and the test units are tested in an increasing order of stress levels. We formulate the prior distribution of the parameters of life-stress function and integrate the engineering knowledge of product failure rate and acceleration factor into the prior. The posterior distribution and the point estimates for the parameters of interest are provided. Through the Markov chain Monte Carlo technique, we demonstrate a nonconjugate prior case using an industrial example. It is shown that with the Bayesian approach, the statistical precision of parameter estimation is improved and, consequently, the required number of failures could be reduced.

  14. Dobutamine cardiac "stress" test reveals increased arrhythmia risk in conscious rats after a single exposure to acrolein

    EPA Science Inventory

    Mild-to-moderate exercise is often used to stress the cardiovascular (CV) system of patients while monitoring them for electrocardiogram (ECG) abnormalities that may indicate underlying CV disease. We previously demonstrated that dobutamine, which increases heart rate (HR) and co...

  15. Up Front: Students Are Chafing under "Test Stress."

    ERIC Educational Resources Information Center

    American School Board Journal, 2001

    2001-01-01

    Although President Bush favors continuous testing, headlines reflect an intense, growing antitesting sentiment. One standard does not fit all, current systems are malfunctioning, and kids are short-changed. A recent report says abstinence-only sex education is ineffective; high teen birth rates underline the need for comprehensive approaches. (MLH)

  16. Timely Follow-Up of Abnormal Diagnostic Imaging Test Results in an Outpatient Setting: Are Electronic Medical Records Achieving Their Potential?

    PubMed Central

    Singh, Hardeep; Thomas, Eric J.; Mani, Shrinidi; Sittig, Dean; Arora, Harvinder; Espadas, Donna; Khan, Myrna M.; Petersen, Laura A.

    2010-01-01

    Background Given the fragmentation of outpatient care, timely follow-up of abnormal diagnostic test results remains a challenge. We hypothesized that an EMR that facilitates the transmission and availability of critical imaging results through either automated notification (alerting) or direct access to the primary report would eliminate this problem. Methods We studied critical imaging alert notifications in the outpatient setting of a tertiary care VA facility from November 2007 to June 2008. Tracking software determined whether the alert was acknowledged (i.e. provider opened the message for viewing) within two weeks of transmission; acknowledged alerts were considered read. We reviewed medical records and contacted providers to determine timely follow-up actions (e.g. ordering a follow-up test or consultation) within 4 weeks of transmission. Multivariable logistic regression models accounting for clustering effect by providers analyzed predictors for two outcomes; lack of acknowledgment and lack of timely follow-up. Results Of 123,638 studies (including X-rays, CT scans, ultrasounds, MRI and mammography), 1196 (0.97%) images generated alerts; 217 (18.1%) of these were unacknowledged. Alerts had a higher risk of being unacknowledged when ordering providers were trainees (OR, 5.58;95%CI, 2.86-10.89) and when dual (more than one provider alerted) as opposed to single communication was used (OR, 2.02;95%CI, 1.22-3.36). Timely follow-up was lacking in 92 (7.7% of all alerts) and was similar for acknowledged and unacknowledged alerts (7.3% vs. 9.7%;p=0.2). Risk for lack of timely follow-up was higher with dual communication (OR,1.99;95%CI, 1.06-3.48) but lower when additional verbal communication was used by the radiologist (OR, 0.12;95%CI: 0.04-0.38). Nearly all abnormal results lacking timely follow-up at 4 weeks were eventually found to have measurable clinical impact in terms of further diagnostic testing or treatment. Conclusions Critical imaging results may not

  17. 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.

  18. Unconscious fearful priming followed by a psychosocial stress test results in higher cortisol levels.

    PubMed

    Hänsel, Alexander; von Känel, Roland

    2013-10-01

    Human perception of stress includes an automatic pathway that processes subliminal presented stimuli below the threshold of conscious awareness. Subliminal stimuli can therefore activate the physiologic stress system. Unconscious emotional signals were shown to significantly moderate reactions and responses to subsequent stimuli, an effect called 'priming'. We hypothesized that subliminal presentation of a fearful signal during the Stroop task compared with an emotionally neutral one will prime stress reactivity in a subsequently applied psychosocial stress task, thereby yielding a significant increase in salivary cortisol. Half of 36 participants were repeatedly presented either a fearful face or a neutral one. After this, all underwent a psychosocial stress task. The fearful group showed a significant increase in cortisol levels (p = 0.022). This change was not affected by sex, age and body mass index, and it also did not change when taking resting cortisol levels into account. Post-hoc analyses showed that the increase in cortisol in the fearful group started immediately after the psychosocial stress test. Hence, subliminal exposure to a fearful signal in combination with the Stroop and followed by a psychosocial stress test leads to an increase in stress reactivity.

  19. Organizational and media stress among professional football players: testing an achievement goal theory model.

    PubMed

    Kristiansen, E; Halvari, H; Roberts, G C

    2012-08-01

    The purpose of this study was to investigate media and coach-athlete stress experienced by professional football players and their relationship to motivational variables by testing an achievement goal theory (AGT) stress model. In order to do so, we developed scales specifically designed to assess media and coach-athlete stress. Eighty-two elite football players (M(age) =25.17 years, SD=5.19) completed a series of questionnaires. Correlations and bootstrapping were used as primary statistical analyses, supplemented by LISREL, to test the hypotheses. Results revealed that a mastery climate was directly and negatively associated with coach-athlete stress, while a performance climate was directly and positively associated with coach-athlete stress. In addition, an indirect positive path between the performance climate and media stress was revealed through ego orientation. These findings support some of the key postulates of AGT; a mastery climate reduces the perception of stress among athletes, and the converse is true for a performance climate. Coaches of elite footballers are advised to try to reduce the emphasis on performance criteria because of its stress-reducing effects.

  20. Effects of chronic and acute stress on rat behaviour in the forced-swim test.

    PubMed

    Suvrathan, Aparna; Tomar, Anupratap; Chattarji, Sumantra

    2010-11-01

    Stress and depression may share common neural plasticity mechanisms. Importantly, the development and reversal of stress-induced plasticity requires time. These temporal aspects, however, are not captured fully in the forced-swim test (FST), a behavioural model for testing antidepressant efficacy, used originally in naïve animals. The present study probed whether and how a rodent model of stress affects behaviour in the FST over time. We found that the intensity and duration of stress are critical in the development of depressive symptoms in male Wistar rats (n = 37) as tested in the FST. Chronic immobilization stress (2 h/day for 10 days) elicited a range of responses, from low to high values of immobility in the FST on day 1, and subsequent immobility on day 2 was inversely related to individual day 1 values. As a whole, chronically stressed rats did not exhibit any significant change in immobility either on day 1 or day 2 compared to control rats. However, climbing behaviour was reduced uniformly from day 1 to day 2, despite the differences in immobility. In contrast, a separate group of rats (n = 30) subjected to the same chronic stressor displayed a significant reduction in open-arm exploration in the elevated plus maze, indicative of a robust increase in anxiety-like behaviour. Furthermore, when the 10-day chronic stress paradigm was reduced to a single 2-h episode of immobilization stress, it triggered a uniform day 1 to day 2 increase in immobility, which was not persistent 10 days later. These results highlight a need for closer examination of the ways in which stress-induced modulation of behaviour in the FST may be used and interpreted in future studies aimed at exploring connections between stress and depression.

  1. Anandamide reverses depressive-like behavior, neurochemical abnormalities and oxidative-stress parameters in streptozotocin-diabetic rats: Role of CB1 receptors.

    PubMed

    de Morais, Helen; de Souza, Camila P; da Silva, Luisa M; Ferreira, Daniele M; Baggio, Cristiane Hatsuko; Vanvossen, Ana Carolina; Cristina de Carvalho, Milene; da Silva-Santos, José Eduardo; Bertoglio, Leandro José; Cunha, Joice M; Zanoveli, Janaina M

    2016-10-01

    The pathophysiology associated with increased prevalence of depression in diabetics is not completely understood, although studies have pointed the endocannabinoid system as a possible target. Then, we aimed to investigate the role of this system in the pathophysiology of depression associated with diabetes. For this, diabetic (DBT) male Wistar rats were intraperitoneally treated with cannabinoid CB1 (AM251, 1mg/kg) or CB2 (AM630, 1mg/kg) receptor antagonists followed by anandamide (AEA, 0.005mg/kg) and then submitted to the forced swimming test (FST). Oxidative stress parameters, CB1 receptor expression and serotonin (5-HT) and noradrenaline levels in the hippocampus (HIP) and prefrontal cortex (PFC) were also performed. It was observed that DBT animals presented a more pronounced depressive-like behavior and increase of CB1 receptor expression in the HIP. AEA treatment induced a significant improvement in the depressive-like behavior, which was reversed by the CB1 antagonist AM251, without affecting the hyperglycemia or weight gain. AEA was also able to restore the elevated CB1 expression and also to elevate the reduced level of 5-HT in the HIP from DBT animals. In addition, AEA restored the elevated noradrenaline levels in the PFC and induced a neuroprotective effect by restoring the decreased reduced glutathione and increased lipid hydroperoxides levels along with the decreased superoxide dismutase activity observed in HIP or PFC. Together, our data suggest that in depression associated with diabetes, the endocannabinoid anandamide has a potential to induce neuroadaptative changes able to improve the depressive-like response by its action as a CB1 receptor agonist.

  2. The Effects of Antidepressants “Fluoxetine and Imipramine” on Vascular Abnormalities and Toll Like Receptor-4 Expression in Diabetic and Non-Diabetic Rats Exposed to Chronic Stress

    PubMed Central

    Habib, Mohamed; Shaker, Safaa; El-Gayar, Nesreen; Aboul-Fotouh, Sawsan

    2015-01-01

    Several studies reveal that diabetes doubles the odds of comorbid depression with evidence of a pro-inflammatory state underlying its vascular complications. Indeed, little information is available about vascular effects of antidepressant drugs in diabetes. Method: We investigated the effect of chronic administration of fluoxetine “FLU” and imipramine “IMIP” on behavioral, metabolic and vascular abnormalities in diabetic and non-diabetic rats exposed to chronic restraint stress (CRS). Results: Both diabetes and CRS induced depressive-like behavior which was more prominent in diabetic/depressed rats; this was reversed by chronic treatment with FLU and IMIP in a comparable manner. Diabetic and non-diabetic rats exposed to CRS exhibited abnormalities in glucose homeostasis, lipid profile and vascular function, manifested by decreased endothelium-dependent relaxation, increased systolic blood pressure and histopathological atherosclerotic changes. Vascular and metabolic dysfunctions were associated with significant increase in aortic expression of TLR-4, and pro-inflammatory cytokines (TNF-α and IL-1ß). FLU ameliorated these metabolic, vascular and inflammatory abnormalities, while IMIP induced either no change or even worsening of some parameters. Conclusion: FLU has favorable effect over IMIP on metabolic, vascular and inflammatory aberrations associated with DM and CRS in Wistar rats, clarifying the preference of FLU over IMIP in management of comorbid depression in diabetic subjects. PMID:25826421

  3. Gold-195m first-pass radionuclide ventriculography, thallium-201 single-photon emission CT, and 12-lead ECG stress testing as a combined procedure

    SciTech Connect

    Kipper, S.L.; Ashburn, W.L.; Norris, S.L.; Rimkus, D.S.; Dillon, W.A.

    1985-09-01

    Graded, sequential, rest/exercise, gold-195m, first-pass ventriculography and thallium-201 (Tl-201) single-photon emission computed tomography (SPECT) were performed simultaneously during a single, electrocardiograph-monitored, bicycle stress test in 24 individuals. The technical aspects and logistics involved in performing this combined radionuclide study are stressed in this preliminary report. Fourteen healthy volunteers each had a normal left ventricular ejection fraction and wall-motion response, along with normal T1-201 perfusion and washout, as determined by both visual and quantitative analysis of the tomographic sections. Each of ten patients with coronary artery disease had at least one abnormality of these parameters. The authors suggest that it is technically feasible to evaluate both cardiac function and myocardial perfusion simultaneously by combing Au-195m ventriculography and Tl-201 SPECT imaging into a single, noninvasive, diagnostic package.

  4. Psychological stress and infertility. Part 2: Psychometric test data.

    PubMed

    Brand, H J

    1982-12-01

    The hypothesis tested in this study was that a group of female functional infertile patients would show significantly more personality maladjustment than a group with definite organic reproductive pathology and a normal fertile group. No significant differences between the functional and organic groups were found on any of the subscores of four personality questionnaires. The normal group (wives of sterile men) scored higher on extraversion than both the functional and organic groups. On self-control the normal group also scored lower (negative connotation) than the other two groups. In general no evidence for personality maladjustment in functional infertility was found.

  5. [Magnesium deficiency and stress: Issues of their relationship, diagnostic tests, and approaches to therapy].

    PubMed

    Tarasov, E A; Blinov, D V; Zimovina, U V; Sandakova, E A

    2015-01-01

    Magnesium plays an important role in the functions of the central nervous system. It takes part in the regulation of the cell membrane, the transmembrane transport of calcium and sodium ions, and metabolic reactions that produce, accumulate, transfer, and utilize energy, free radicals, and their oxidation products. The magnesium-containing substances include many sequestered antigens, such as glial fibrillary acidic protein, S100, and neuron-specific enolase; magnesium may act as a neuroprotector that is able to modulate the regulation of blood-brain barrier permeability. Investigations have demonstrated a relationship between the manifestations of stress reactions (anxiety, autonomic dysfunction, and maladjustment) and magnesium deficiency (MD). Thus, mental and physical stresses cause an increase in magnesium elimination from the body. MD in turn enhances a response to stress, by paradoxically aggravating its sequels. Compensation for MD increases the ability of the nervous system to resist stress. The valid diagnosis of MD present difficulties; namely, a blood magnesium concentration decrease below 0.8 mmol/l is evidence of MD; but the constant blood level of magnesium may be long maintained due to its release from the bone tissue depot. So it is necessary to keep in mind the clinical manifestations of MD. The authors have developed and tested a simple rapid MD assessment test and a stress resistance self-rating test. The proposed tests will help to screen stress resistance and MD in outpatient settings.

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

    NASA Technical Reports Server (NTRS)

    Johnson, G. M.

    1976-01-01

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

  7. Stress Testing Recovery EMG for Evaluation of Biofeedback and Progressive Muscle Relaxation Training Effects.

    ERIC Educational Resources Information Center

    Sime, Wesley E.; DeGood, Douglas E.

    The purpose of this investigation was to assess biofeedback (BF) and progressive muscle relaxation (PMR) and placebo-control training by means of a post-training transfer test. The subjects for the research were 30 women. Initial tests consisted of measuring the electromyographic response of the frontalis muscle of the forehead to stress. After…

  8. Stress and Anxiety Surrounding Forthcoming Standard Assessment Tests in English Schoolchildren

    ERIC Educational Resources Information Center

    Putwain, Dave W.; Connors, Liz; Woods, Kevin; Nicholson, Laura J.

    2012-01-01

    The Standard Assessment Tests (SATs) taken by pupils in their final year of primary schooling in England have been widely criticised for placing children under too pressure and contributing to an increase in test-related stress and anxiety. In this exploratory study we set out to explore the experiences of forthcoming SATs in a small sample of…

  9. Initial Development and Factor Structure of the Educator Test Stress Inventory

    ERIC Educational Resources Information Center

    von der Embse, Nathaniel P.; Kilgus, Stephen P.; Solomon, Hadley J.; Bowler, Mark; Curtiss, Caroline

    2015-01-01

    With the proliferation of test-based accountability policies, educators and students alike are under pressure to improve test performance. However, little is known regarding the stress experienced by educators in response to these policies. The purpose of this article is to describe the initial development and validation of a new measure of stress…

  10. Partial Shade Stress Test for Thin-Film Photovoltaic Modules: Preprint

    SciTech Connect

    Silverman, Timothy J.; Deceglie, Michael G.; Deline, Chris; Kurtz, Sarah

    2015-09-02

    Partial shade of monolithic thin-film PV modules can cause reverse-bias conditions leading to permanent damage. In this work, we propose a partial shade stress test for thin-film PV modules that quantifies permanent performance loss. We designed the test with the aid of a computer model that predicts the local voltage, current and temperature stress that result from partial shade. The model predicts the module-scale interactions among the illumination pattern, the electrical properties of the photovoltaic material and the thermal properties of the module package. The test reproduces shading and loading conditions that may occur in the field. It accounts for reversible light-induced performance changes and for additional stress that may be introduced by light-enhanced reverse breakdown. We present simulated and experimental results from the application of the proposed test.

  11. Local delamination in laminates with angle ply matrix cracks. Part 1: Tension tests and stress analysis

    NASA Technical Reports Server (NTRS)

    Obrien, T. Kevin; Hooper, S. J.

    1991-01-01

    Quasi-static tension tests were conducted on AS4/3501-6 graphite epoxy laminates. Dye penetrant enhanced x-radiography was used to document the onset of matrix cracking and the onset of local delaminations at the intersection of the matrix cracks and the free edge. Edge micrographs taken after the onset of damage were used to verify the location of the matrix cracks and local delamination through the laminate thickness. A quasi-3D finite element analysis was conducted to calculate the stresses responsible for matrix cracking in the off-axis plies. Laminated plate theory indicated that the transverse normal stresses were compressive. However, the finite element analysis yielded tensile transverse normal stresses near the free edge. Matrix cracks formed in the off-axis plies near the free edge where in-plane transverse stresses were tensile and had their greatest magnitude. The influence of the matrix crack on interlaminar stresses is also discussed.

  12. Development of the Stress of Immigration Survey: A Field Test Among Mexican Immigrant Women.

    PubMed

    Sternberg, Rosa Maria; Nápoles, Anna Maria; Gregorich, Steven; Paul, Steven; Lee, Kathryn A; Stewart, Anita L

    2016-01-01

    The Stress of Immigration Survey (SOIS) is a screening tool used to assess immigration-related stress. The mixed methods approach included concept development, pretesting, field testing, and psychometric evaluation in a sample of 131 low-income women of Mexican descent. The 21-item SOIS screens for stress related to language, immigrant status, work issues, yearning for family and home country, and cultural dissonance. Mean scores ranged from 3.6 to 4.4 (a scale of 1-5, higher is more stress). Cronbach α values were more than 0.80 for all subscales. The SOIS may be a useful screening tool for detecting high levels of immigration-related stress in low-income Mexican immigrant women. PMID:26605954

  13. Development of the Stress of Immigration Survey: A Field Test Among Mexican Immigrant Women.

    PubMed

    Sternberg, Rosa Maria; Nápoles, Anna Maria; Gregorich, Steven; Paul, Steven; Lee, Kathryn A; Stewart, Anita L

    2016-01-01

    The Stress of Immigration Survey (SOIS) is a screening tool used to assess immigration-related stress. The mixed methods approach included concept development, pretesting, field testing, and psychometric evaluation in a sample of 131 low-income women of Mexican descent. The 21-item SOIS screens for stress related to language, immigrant status, work issues, yearning for family and home country, and cultural dissonance. Mean scores ranged from 3.6 to 4.4 (a scale of 1-5, higher is more stress). Cronbach α values were more than 0.80 for all subscales. The SOIS may be a useful screening tool for detecting high levels of immigration-related stress in low-income Mexican immigrant women.

  14. Synchronized stress-PALS test on a series of polyester copolymer glasses

    NASA Astrophysics Data System (ADS)

    Li, Lei; Yee, Albert F.

    2001-03-01

    Previous work in our group suggests that, in craze nucleation, only when a nanovoid grows to a critical size can it serve as a nucleus for stable craze growth. However, what factors influence this nanovoid growth process remains unclear. A new technique, synchronized stress-PALS test, has been established to study the change in size and intensity of nanovoids when polymer glasses are under stress. A series of glassy copolymers based on poly (ethylene terephthalate) (PET) and poly (1,4-cyclohexylenedimethylene terephthalate) (PCT) were investigated by synchronized stress-PALS at different stress levels. The results suggest that both stress level and chain mobility of the polymers influence nanovoid growth. Based on these experimental results, a craze nucleation model has been proposed. This model, based on thermodynamic and kinetic analysis, show that the craze nucleation process is determined by the modulus, surface energy and chain mobility of polymer glasses.

  15. Assessing corrosion problems in photovoltaic cells via electrochemical stress testing

    NASA Technical Reports Server (NTRS)

    Shalaby, H.

    1985-01-01

    A series of accelerated electrochemical experiments to study the degradation properties of polyvinylbutyral-encapsulated silicon solar cells has been carried out. The cells' electrical performance with silk screen-silver and nickel-solder contacts was evaluated. The degradation mechanism was shown to be electrochemical corrosion of the cell contacts; metallization elements migrate into the encapsulating material, which acts as an ionic conducting medium. The corrosion products form a conductive path which results in a gradual loss of the insulation characteristics of the encapsulant. The precipitation of corrosion products in the encapsulant also contributes to its discoloration which in turn leads to a reduction in its transparency and the consequent optical loss. Delamination of the encapsulating layers could be attributed to electrochemical gas evolution reactions. The usefulness of the testing technique in qualitatively establishing a reliability difference between metallizations and antireflection coating types is demonstrated.

  16. Neutron measurements of stresses in a test artifact produced by laser-based additive manufacturing

    SciTech Connect

    Gnäupel-Herold, Thomas; Slotwinski, John; Moylan, Shawn

    2014-02-18

    A stainless steel test artifact produced by Direct Metal Laser Sintering and similar to a proposed standardized test artifact was examined using neutron diffraction. The artifact contained a number of structures with different aspect ratios pertaining to wall thickness, height above base plate, and side length. Through spatial resolutions of the order of one millimeter the volumetric distribution of stresses in several was measured. It was found that the stresses peak in the tensile region around 500 MPa near the top surface, with balancing compressive stresses in the interior. The presence of a support structure (a one millimeter high, thin walled, hence weaker, lattice structure deposited on the base plate, followed by a fully dense AM structure) has only minor effects on the stresses.

  17. Stress induced by the socially evaluated cold-pressor test cause equivalent deficiencies of sensory gating in male subjects with schizophrenia and healthy controls.

    PubMed

    Rubio, Gabriel; López-Muñoz, Francisco; Jurado-Barba, Rosa; Martínez-Gras, Isabel; Rodríguez-Jiménez, Roberto; Espinosa, Regina; Pérez-Nieto, Miguel Ángel; Moratti, Stephan; Jiménez-Arriero, Miguel Ángel; Carlos Leza, Juan

    2015-08-30

    It is known that patients with schizophrenia show a deficiency in the prepulse inhibition reflex (PPI). These patients display abnormalities in autonomic nervous system and hypothalamic-pituitary-adrenal function and may have an altered sensitivity to stress. To date, no studies have been carried out to determine the effect of acute stress on the PPI. We investigated whether there was a differential response in reactivity to acute stress caused by the socially evaluated cold-pressor test (SECPT) in a sample of 58 chronic male patients with schizophrenia and 28 healthy control subjects. PPI, salivary cortisol and heart rate (HR) were measured. The patients were evaluated in two sessions (with and without the SECPT) 72 h apart and basal measurements were carried out and 30 min post-startle probe. We found an increase in salivary cortisol levels and the HR with SECPT condition in both groups and a significantly lower PPI% in patients with schizophrenia. The most relevant findings of this study are that the impairment of the PPI is increased by stress. Stress-induced increase in cortisol in both groups, mainly in healthy control group which allows us to hypothesize that at least such deterioration may be due to the hypercortisolemia caused by the SECPT.

  18. Stress induced by the socially evaluated cold-pressor test cause equivalent deficiencies of sensory gating in male subjects with schizophrenia and healthy controls.

    PubMed

    Rubio, Gabriel; López-Muñoz, Francisco; Jurado-Barba, Rosa; Martínez-Gras, Isabel; Rodríguez-Jiménez, Roberto; Espinosa, Regina; Pérez-Nieto, Miguel Ángel; Moratti, Stephan; Jiménez-Arriero, Miguel Ángel; Carlos Leza, Juan

    2015-08-30

    It is known that patients with schizophrenia show a deficiency in the prepulse inhibition reflex (PPI). These patients display abnormalities in autonomic nervous system and hypothalamic-pituitary-adrenal function and may have an altered sensitivity to stress. To date, no studies have been carried out to determine the effect of acute stress on the PPI. We investigated whether there was a differential response in reactivity to acute stress caused by the socially evaluated cold-pressor test (SECPT) in a sample of 58 chronic male patients with schizophrenia and 28 healthy control subjects. PPI, salivary cortisol and heart rate (HR) were measured. The patients were evaluated in two sessions (with and without the SECPT) 72 h apart and basal measurements were carried out and 30 min post-startle probe. We found an increase in salivary cortisol levels and the HR with SECPT condition in both groups and a significantly lower PPI% in patients with schizophrenia. The most relevant findings of this study are that the impairment of the PPI is increased by stress. Stress-induced increase in cortisol in both groups, mainly in healthy control group which allows us to hypothesize that at least such deterioration may be due to the hypercortisolemia caused by the SECPT. PMID:26154819

  19. Stress Testing of the Philips 60W Replacement Lamp L Prize Entry

    SciTech Connect

    Poplawski, Michael E.; Ledbetter, Marc R.; Smith, Mark

    2012-04-24

    The Pacific Northwest National Laboratory, operated by Battelle for the U.S. Department of Energy, worked with Intertek to develop a procedure for stress testing medium screw-base light sources. This procedure, composed of alternating stress cycles and performance evaluation, was used to qualitatively compare and contrast the durability and reliability of the Philips 60W replacement lamp L Prize entry with market-proven compact fluorescent lamps (CFLs) with comparable light output and functionality. The stress cycles applied simultaneous combinations of electrical, thermal, vibration, and humidity stresses of increasing magnitude. Performance evaluations measured relative illuminance, x chromaticity and y chromaticity shifts after each stress cycle. The Philips L Prize entry lamps appear to be appreciably more durable than the incumbent energy-efficient technology, as represented by the evaluated CFLs, and with respect to the applied stresses. Through the course of testing, all 15 CFL samples permanently ceased to function as a result of the applied stresses, while only 1 Philips L Prize entry lamp exhibited a failure, the nature of which was minor, non-destructive, and a consequence of a known (and resolved) subcontractor issue. Given that current CFL technology appears to be moderately mature and no Philips L Prize entry failures could be produced within the stress envelope causing 100 percent failure of the benchmark CFLs, it seems that, in this particular implementation, light-emitting diode (LED) technology would be much more durable in the field than current CFL technology. However, the Philips L Prize entry lamps used for testing were carefully designed and built for the competition, while the benchmark CFLs were mass produced for retail sale—a distinction that should be taken into consideration. Further reliability testing on final production samples would be necessary to judge the extent to which the results of this analysis apply to production versions

  20. Derivation and test of elevated temperature thermal-stress-free fastener concept

    NASA Technical Reports Server (NTRS)

    Sawyer, J. W.; Blosser, M. L.; Mcwithey, R. R.

    1985-01-01

    Future aerospace vehicles must withstand high temperatures and be able to function over a wide temperature range. New composite materials are being developed for use in designing high-temperature lightweight structures. Due to the difference between coefficients of thermal expansion for the new composite materials and conventional high-temperature metallic fasteners, innovative joining techniques are needed to produce tight joints at all temperatures without excessive thermal stresses. A thermal-stress-free fastening technique is presented that can be used to provide structurally tight joints at all temperatures even when the fastener and joined materials have different coefficients of thermal expansion. The derivation of thermal-stress-free fasteners and joint shapes is presented for a wide variety of fastener materials and materials being joined together. Approximations to the thermal-stress-free shapes that result in joints with low-thermal-stresses and that simplify the fastener/joint shape are discussed. The low-thermal-stress fastener concept is verified by thermal and shear tests in joints using oxide-dispersion-strengthened alloy fasteners in carbon-carbon material. The test results show no evidence of thermal stress damage for temperatures up to 2000 F and the resulting joints carried shear loads at room temperature typical of those for conventional joints.

  1. A test for interfacial effects and stress transfer in ceramic matrix composites

    NASA Technical Reports Server (NTRS)

    Bascom, Willard D.; Lee, Ilzoo

    1988-01-01

    The efforts to fabricate single embedded filament specimens of carbon and SiC fibers were unsuccessful largely due to the thermal stresses resulting from differences in thermal coefficient of expansion. Other factors appear to have been involved including embrittlement of the metal substrate by the H2 gas in the chemical vapor deposition flow stream and reaction layers formed between the silicon carbide and the metal substrate. The carbon fiber may have been attacked by the CVD reactant. It is concluded that these differential stresses are so large as to make the embedded fiber test impractical for the study of interphase effects and stress transfer in fiber ceramic matrix systems.

  2. Tests for the determination of the stress condition in tension fields

    NASA Technical Reports Server (NTRS)

    Lahde, R; Wagner, H

    1936-01-01

    The present experiments treat the stress of actual tension fields within the elastic range. They give the magnitude of the flexural stresses due to wrinkling. They also disclose, particularly by slightly exceeded buckling load, the marked unloading - as compared with the tension-field theory - of the uprights as a result of the flexural stiffness of the web plate. The test sheets were clamped at the edges and brought to buckling through shearing and compressive stresses applied in the direction of the long sides.

  3. Oxygen desaturation during a 6-minute walk test as a predictor of maximal exercise-induced gas exchange abnormalities in sarcoidosis

    PubMed Central

    Chenivesse, Cecile; Boulanger, Sarah; Langlois, Carole; Wemeau-Stervinou, Lidwine; Perez, Thierry

    2016-01-01

    Background Common tests for evaluating gas exchange impairment have different strengths and weaknesses. Alveolar-to-arterial oxygen pressure difference (AaDO2) at peak exercise is a sensitive indicator but it cannot be measured repeatedly. Diffusing capacity of the lung for carbon monoxide (DLco) is measured at rest and may be too insensitive to predict the effects of exercise on gas exchange impairment. Oxygen desaturation during a 6-minute walk test (∆SpO2-6MWT) can be measured repeatedly, but its value in sarcoidosis is unknown. Here, we evaluated the ability of ∆SpO2-6MWT and DLco to predict gas exchange impairment during exercise in sarcoidosis. Methods This retrospective study of 130 subjects with sarcoidosis investigated the relationship between DLco, ∆SpO2-6MWT, and peak AaDO2 using correlation tests, inter-test reliability analyses, and predictive values. For the analyses of inter-test reliability and predictive values, DLco, peak AaDO2, and ∆SpO2-6MWT were considered as binary variables (normal/abnormal) according to previously defined thresholds. Results Correlation coefficients between DLco, ∆SpO2-6MWT, and peak AaDO2 were intermediate (0.53–0.67, P<0.0003) and Kappa coefficients were low (0.21–0.42, P=0.0003–0.02). DLco predicted (I) increased peak AaDO2 with a positive predictive value (PPV) of 66% and a negative predictive value (NPV) of 78% and (II) increased ∆SpO2-6MWT with a PPV at 36% and an NPV at 88%. Normal DLco was a good predictor of the absence of severe desaturation during the 6MWT (94% NPV) and at peak exercise during cardiopulmonary exercise test (CPET) (100% NPV). ∆SpO2-6MWT predicted peak AaDO2 increase with a PPV of 74% and an NPV of 60%. Conclusions In a large population of sarcoidosis patients, neither ∆SpO2-6MWT nor DLco was a good predictor of increased peak AaDO2. In contrast, normal DLco was a good predictor of the absence of severe desaturation during the 6MWT and at peak exercise during CPET.

  4. Oxygen desaturation during a 6-minute walk test as a predictor of maximal exercise-induced gas exchange abnormalities in sarcoidosis

    PubMed Central

    Chenivesse, Cecile; Boulanger, Sarah; Langlois, Carole; Wemeau-Stervinou, Lidwine; Perez, Thierry

    2016-01-01

    Background Common tests for evaluating gas exchange impairment have different strengths and weaknesses. Alveolar-to-arterial oxygen pressure difference (AaDO2) at peak exercise is a sensitive indicator but it cannot be measured repeatedly. Diffusing capacity of the lung for carbon monoxide (DLco) is measured at rest and may be too insensitive to predict the effects of exercise on gas exchange impairment. Oxygen desaturation during a 6-minute walk test (∆SpO2-6MWT) can be measured repeatedly, but its value in sarcoidosis is unknown. Here, we evaluated the ability of ∆SpO2-6MWT and DLco to predict gas exchange impairment during exercise in sarcoidosis. Methods This retrospective study of 130 subjects with sarcoidosis investigated the relationship between DLco, ∆SpO2-6MWT, and peak AaDO2 using correlation tests, inter-test reliability analyses, and predictive values. For the analyses of inter-test reliability and predictive values, DLco, peak AaDO2, and ∆SpO2-6MWT were considered as binary variables (normal/abnormal) according to previously defined thresholds. Results Correlation coefficients between DLco, ∆SpO2-6MWT, and peak AaDO2 were intermediate (0.53–0.67, P<0.0003) and Kappa coefficients were low (0.21–0.42, P=0.0003–0.02). DLco predicted (I) increased peak AaDO2 with a positive predictive value (PPV) of 66% and a negative predictive value (NPV) of 78% and (II) increased ∆SpO2-6MWT with a PPV at 36% and an NPV at 88%. Normal DLco was a good predictor of the absence of severe desaturation during the 6MWT (94% NPV) and at peak exercise during cardiopulmonary exercise test (CPET) (100% NPV). ∆SpO2-6MWT predicted peak AaDO2 increase with a PPV of 74% and an NPV of 60%. Conclusions In a large population of sarcoidosis patients, neither ∆SpO2-6MWT nor DLco was a good predictor of increased peak AaDO2. In contrast, normal DLco was a good predictor of the absence of severe desaturation during the 6MWT and at peak exercise during CPET. PMID

  5. A single exposure to diesel exhaust increases the risk of triggered cardiac arrhythmias in conscious rats during dobutamine cardiac "stress" test.

    EPA Science Inventory

    Mild-to-moderate exercise is often used to stress the cardiovascular (CV) system of patients while monitoring them for electrocardiogram (ECG) abnormalities that may indicate underlying CV disease. We previously used dobutamine, which increases heart rate (HR) and contractility, ...

  6. Residual stresses in silicon carbide-zircon composites from thermal expansion measurements and fiber pushout tests

    SciTech Connect

    Reddy, S.K.; Kumar, S.; Singh, R.N. . Dept. of Materials Science and Engineering)

    1994-12-01

    Coefficients of thermal expansion (CTE) in the axial direction of two types of SiC fibers, monolithic zircon, monolithic SiC, and several SiC[sub f]-zircon composites were measured in the temperature range of 50 to 1,380 C. The measured CTE values of composites were compared with values predicted by the rule-of-mixtures approach, and a small difference in measured and calculated values was ascribed to the nature of interfacial bonding and assumptions implicit in the rule-of-mixture approach. Fiber pushout tests were performed on these composites and the residual stresses were extracted from the analysis of the load-displacement plots in terms of the shear-lag and progressive debonding models. The radial and axial residual stresses arising from the mismatch in CTE were calculated and compared with values obtained from the fiber pushout tests. The fiber pushout tests in general produced lower values of the residual stresses, but the residual stresses obtained using shear-lag analysis were in good agreement with the calculated values based on the CTE mismatch in composites with lower values of the interfacial shear stress. The influence of anisotropic fiber expansion in the radial and axial directions on the radial and axial residual stresses in composites were also examined.

  7. The patient's motivation during bicycle stress ECG test is dependent on the investigator's sex in male patients.

    PubMed

    Jung, Christian; Ferrari, Markus; Goebel, Bjoern; Figulla, Hans R

    2009-08-21

    The exercise electrocardiogram is a commonly used non-invasive method for detection of electrocardiogram (ECG) changes secondary to myocardial ischemia. Studies showed the importance of the patient's motivation to reach the estimated submaximal heart rate. The purpose of this study was to test whether the patient's motivation is dependent on the investigator's sex. We included 1170 patients (in-hospital patients and out-clinic patients; 63.5% male, 36.5% female) in this study. Stress test data (stationary bicycle with gradually increasing intensity) were collected retrospectively: patient's age, sex, maximal power stage, ECG-abnormalities, angina pectoris, and attending physician's sex. Male patients achieved a higher power stage than their female counterparts (126.5+/-47.7 W vs. 89.7+/-30.4 W). When male patients were supervised by a female doctor they reached higher maximum power stages (136.6+/-53.5 W vs. 121.6+/-43.3 W; p=0,001), more often the submaximal heart rate (47.9% vs. 38.3%; p=0.02) but complained less frequent about angina pectoris (5.6% vs. 17.3%). In contrast, none of these parameters was dependent on the attending physician's sex in female patients. The attending physician's sex influences the maximum exercise ability and the incidence of complaints during bicycle stress in male patients but not in females. We would speculate that men try to impress women with physical strength and try to dissimulate physical discomfort or pain. This could possibly influence the validity of such non-invasive methods with exercise dependent detection of myocardial ischemia.

  8. Predator Stress-Induced CRF Release Causes Enduring Sensitization of Basolateral Amygdala Norepinephrine Systems that Promote PTSD-Like Startle Abnormalities

    PubMed Central

    Rajbhandari, Abha K.

    2015-01-01

    The neurobiology of post-traumatic stress disorder (PTSD) remains unclear. Intense stress promotes PTSD, which has been associated with exaggerated startle and deficient sensorimotor gating. Here, we examined the long-term sequelae of a rodent model of traumatic stress (repeated predator exposure) on amygdala systems that modulate startle and prepulse inhibition (PPI), an operational measure of sensorimotor gating. We show in rodents that repeated psychogenic stress (predator) induces long-lasting sensitization of basolateral amygdala (BLA) noradrenergic (NE) receptors (α1) via a corticotropin-releasing factor receptor 1 (CRF-R1)-dependent mechanism, and that these CRF1 and NE α1 receptors are highly colocalized on presumptive excitatory output projection neurons of the BLA. A profile identical to that seen with predator exposure was produced in nonstressed rats by intra-BLA infusions of CRF (200 ng/0.5 μl), but not by repeated NE infusions (20 μg/0.5 μl). Infusions into the adjacent central nucleus of amygdala had no effect. Importantly, the predator stress- or CRF-induced sensitization of BLA manifested as heightened startle and PPI deficits in response to subsequent subthreshold NE system challenges (with intra-BLA infusions of 0.3 μg/0.5 μl NE), up to 1 month after stress. This profile of effects closely resembles aspects of PTSD. Hence, we reveal a discrete neural pathway mediating the enhancement of NE system function seen in PTSD, and we offer a model for characterizing potential new treatments that may work by modulating this BLA circuitry. SIGNIFICANCE STATEMENT The present findings reveal a novel and discrete neural substrate that could underlie certain core deficits (startle and prepulse inhibition) that are observed in post-traumatic stress disorder (PTSD). It is shown here that repeated exposure to a rodent model of traumatic stress (predator exposure) produces a long-lasting sensitization of basolateral amygdala noradrenergic substrates [via a

  9. Failure Modes in Capacitors When Tested Under a Time-Varying Stress

    NASA Technical Reports Server (NTRS)

    Liu, David (Donhang)

    2011-01-01

    Power-on failure has been the prevalent failure mechanism for solid tantalum capacitors in decoupling applications. A surge step stress test (SSST) has been previously applied to identify the critical stress level of a capacitor batch to give some predictability to the power-on failure mechanism [1]. But SSST can also be viewed as an electrically destructive test under a time-varying stress (voltage). It consists of rapidly charging the capacitor with incremental voltage increases, through a low resistance in series, until the capacitor under test is electrically shorted. When the reliability of capacitors is evaluated, a highly accelerated life test (HALT) is usually adopted since it is a time-efficient method of determining the failure mechanism; however, a destructive test under a time-varying stress such as SSST is even more time efficient. It usually takes days or weeks to complete a HALT test, but it only takes minutes for a time-varying stress test to produce failures. The advantage of incorporating a specific time-varying stress profile into a statistical model is significant in providing an alternative life test method for quickly revealing the failure mechanism in capacitors. In this paper, a time-varying stress that mimics a typical SSST has been incorporated into the Weibull model to characterize the failure mechanism in different types of capacitors. The SSST circuit and transient conditions for correctly surge testing capacitors are discussed. Finally, the SSST was applied for testing Ta capacitors, polymer aluminum capacitors (PA capacitors), and multi-layer ceramic (MLC) capacitors with both precious metal electrodes (PME) and base metal electrodes (BME). The test results are found to be directly associated with the dielectric layer breakdown in Ta and PA capacitors and are independent of the capacitor values, the way the capacitors were built, and the capacitors manufacturers. The test results also show that MLC capacitors exhibit surge breakdown

  10. Cardiac CT vs. Stress Testing in Patients with Suspected Coronary Artery Disease: Review and Expert Recommendations

    PubMed Central

    Rahsepar, Amir Ali; Arbab-Zadeh, Armin

    2015-01-01

    Diagnosis and management of coronary artery disease represent a major challenge to our health care systems affecting millions of patients each year. Until recently, the diagnosis of coronary artery disease could be conclusively determined only by invasive coronary angiography. To avoid risks from cardiac catheterization, many healthcare systems relied on stress testing as gatekeeper for coronary angiography. Advancements in cardiac computed tomography angiography technology now allows to noninvasively visualize coronary artery disease, challenging the role of stress testing as the default noninvasive imaging tool for evaluating patients with chest pain. In this review, we summarize current data on the clinical utility of cardiac computed tomography and stress testing in stable patients with suspected coronary artery disease. PMID:26500716

  11. Thermal stress development in a nickel based superalloy during weldability test

    SciTech Connect

    Feng, Z.; Zacharia, T.; David, S.A.

    1997-11-01

    A finite element model has been developed to quantitatively evaluate the local thermomechanical conditions for weld metal solidification cracking in a laboratory weldability test (the Sigmajig test). The loading mechanism in the Sigmajig test was simulated by means of nonlinear spring elements. The effects of weld pool solidification on the thermal and mechanical behaviors of the specimen were considered. An efficient algorithm was developed to include the solidification effects in the material constitutive relations. Stress/temperature/location diagrams were constructed to reveal the local stress development behind the traveling weld pool where solidification cracking occurs. Based on the concept of the material resistance to cracking and the mechanical driving force for cracking, the calculated local stress in the solidification temperature range was used to explain the experimentally observed cracking initiation behaviors of a nickel-based superalloy single crystal under different welding and loading conditions.

  12. A test for interfacial effects and stress transfer in ceramic matrix composites

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A test specimen was devised for measuring stress transfer between a high modulus fiber and a ceramic matrix. Single filaments of SiC were embedded in chemically vapor deposited SiC on a thin plate of molybdenum. The CVD overcoating which encapsulated the fiber was continuous with a coating of SiC on the molybdenum. When placed in a microtensile test device and loaded in the fiber direction, the fiber fracture characteristics provide information on the fiber/matrix adhesion and stress transfer. Problems were encountered due to the formation of a weak boundary between the SiC and the molybdenum which obviated any meaningful tensile tests. Also, the high CVD temperature used in fabricating these specimens restrict the fiber, matrix (and substrate) to materials having similar thermal coefficients of expansion in order to minimize thermal stresses.

  13. Synthetic sea water - An improved stress corrosion test medium for aluminum alloys

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    A major problem in evaluating the stress corrosion cracking resistance of aluminum alloys by alternate immersion in 3.5 percent salt (NaCl) water is excessive pitting corrosion. Several methods were examined to eliminate this problem and to find an improved accelerated test medium. These included the addition of chromate inhibitors, surface treatment of specimens, and immersion in synthetic sea water. The results indicate that alternate immersion in synthetic sea water is a very promising stress corrosion test medium. Neither chromate inhibitors nor surface treatment (anodize and alodine) of the aluminum specimens improved the performance of alternate immersion in 3.5 percent salt water sufficiently to be classified as an effective stress corrosion test method.

  14. Characterization Of Flow Stress Of Different AA6082 Alloys By Means Of Hot Torsion Test

    SciTech Connect

    Donati, Lorenzo; El Mehtedi, Mohamad

    2011-05-04

    FEM simulations are become the most powerful tools in order to optimize the different aspects of the extrusion process and an accurate flow stress definition of the alloy is a prerequisite for a reliable effectiveness of the simulation. In the paper the determination of flow stress by means of hot torsion test is initially presented and discussed: the several approximations that are usually introduced in flow stress computation are described and computed for an AA6082 alloy in order to evidence the final effect on curves shapes. The procedure for regressing the parameters of the sinhyperbolic flow stress definition is described in detailed and applied to the described results. Then four different alloys, extracted by different casting batches but all namely belonging to the 6082 class, were hot torsion tested in comparable levels of temperature and strain rate up to specimen failure. The results are analyzed and discussed in order to understand if a mean flow stress behavior can be identified for the whole material class at the different tested conditions or if specific testing conditions (chemical composition of the alloy, specimen shape, etc) influence the materials properties to a higher degree.

  15. Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia

    PubMed Central

    de Araujo, Ana Carla Pereira; Santos, Bruno F. de Oliveira; Calasans, Flavia Ricci; Pinto, Ibraim M. Francisco; de Oliveira, Daniel Pio; Melo, Luiza Dantas; Andrade, Stephanie Macedo; Tavares, Irlaneide da Silva; Sousa, Antonio Carlos Sobral; Oliveira, Joselina Luzia Menezes

    2014-01-01

    Background Studies have demonstrated the diagnostic accuracy and prognostic value of physical stress echocardiography in coronary artery disease. However, the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia is limited. Objective To evaluate the effectiveness of physical stress echocardiography in the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia. Methods This is a retrospective cohort in which 866 consecutive patients with exercise test positive for myocardial ischemia, and who underwent physical stress echocardiography were studied. Patients were divided into two groups: with physical stress echocardiography negative (G1) or positive (G2) for myocardial ischemia. The endpoints analyzed were all‑cause mortality and major cardiac events, defined as cardiac death and non-fatal acute myocardial infarction. Results G2 comprised 205 patients (23.7%). During the mean 85.6 ± 15.0-month follow-up, there were 26 deaths, of which six were cardiac deaths, and 25 non-fatal myocardial infarction cases. The independent predictors of mortality were: age, diabetes mellitus, and positive physical stress echocardiography (hazard ratio: 2.69; 95% confidence interval: 1.20 – 6.01; p = 0.016). The independent predictors of major cardiac events were: age, previous coronary artery disease, positive physical stress echocardiography (hazard ratio: 2.75; 95% confidence interval: 1.15 – 6.53; p = 0.022) and absence of a 10% increase in ejection fraction. All-cause mortality and the incidence of major cardiac events were significantly higher in G2 (p < 0. 001 and p = 0.001, respectively). Conclusion Physical stress echocardiography provides additional prognostic information in patients with exercise test positive for myocardial ischemia. PMID:25352460

  16. Quantification of Shear Deformations and Corresponding Stresses in the Biaxially Tested Human Myocardium.

    PubMed

    Sommer, Gerhard; Haspinger, Daniel Ch; Andrä, Michaela; Sacherer, Michael; Viertler, Christian; Regitnig, Peter; Holzapfel, Gerhard A

    2015-10-01

    One goal of cardiac research is to perform numerical simulations to describe/reproduce the mechanoelectrical function of the human myocardium in health and disease. Such simulations are based on a complex combination of mathematical models describing the passive mechanical behavior of the myocardium and its electrophysiology, i.e., the activation of cardiac muscle cells. The problem in developing adequate constitutive models is the shortage of experimental data suitable for detailed parameter estimation in specific functional forms. A combination of shear and biaxial extension tests with different loading protocols on different specimen orientations is necessary to capture adequately the direction-dependent (orthotropic) response of the myocardium. In most experimental animal studies, where planar biaxial extension tests on the myocardium have been conducted, the generated shear stresses were neither considered nor discussed. Hence, in this study a method is presented which allows the quantification of shear deformations and related stresses. It demonstrates an approach for experimenters as to how the generation of these shear stresses can be minimized during mechanical testing. Experimental results on 14 passive human myocardial specimens, obtained from nine human hearts, show the efficiency of this newly developed method. Moreover, the influence of the clamping technique of the specimen, i.e., the load transmission between the testing device and the tissue, on the stress response is determined by testing an isotropic material (Latex). We identified that the force transmission between the testing device and the specimen by means of hooks and cords does not influence the performed experiments. We further showed that in-plane shear stresses definitely exist in biaxially tested human ventricular myocardium, but can be reduced to a minimum by preparing the specimens in an appropriate manner. Moreover, we showed whether shear stresses can be neglected when performing

  17. Stress analysis and testing of the outer capsule design for the Strontium Heat Source Development Program

    SciTech Connect

    Simonen, F.A.; Shippell, R.J. Jr.; Atteridge, D.G.

    1980-01-01

    The objective of the Strontium Heat Source Development Program is to obtain the data needed to license /sup 90/SrF/sub 2/ heat sources - specifically the /sup 90/SrF/sub 2/ capsules produced in the Waste Encapsulation and Storage Facility (WESF) at Hanford. Toward this end, a high integrity outer capsule has been designed to replace the present outer capsule of the WESF /sup 90/SrF/sub 2/ capsule. The proposed design of a Hastelloy S outer capsule which features a mechanical interlock type of end closure is described. Qualification testing requirements are outlined, and stress analyses and developmental tests are described. These tests were performed on AISI-1018 steel stand-in capsules, and included both external pressure and impact tests. The external pressure tests showed that stress calculations seriously overestimated the pressure capability of the outer capsule. Possible reasons for the lack of agreement between the tests and the analyses are evaluated. The stress analyses and tests results indicate that the proposed outer capsule will meet the heat source qualification requirements. Future tests will be conducted to experimentally verify that the Hastelloy S outer capsule in an aged condition meets the structural integrity requirements.

  18. Complex patterns of abnormal heartbeats

    NASA Technical Reports Server (NTRS)

    Schulte-Frohlinde, Verena; Ashkenazy, Yosef; Goldberger, Ary L.; Ivanov, Plamen Ch; Costa, Madalena; Morley-Davies, Adrian; Stanley, H. Eugene; Glass, Leon

    2002-01-01

    Individuals having frequent abnormal heartbeats interspersed with normal heartbeats may be at an increased risk of sudden cardiac death. However, mechanistic understanding of such cardiac arrhythmias is limited. We present a visual and qualitative method to display statistical properties of abnormal heartbeats. We introduce dynamical "heartprints" which reveal characteristic patterns in long clinical records encompassing approximately 10(5) heartbeats and may provide information about underlying mechanisms. We test if these dynamics can be reproduced by model simulations in which abnormal heartbeats are generated (i) randomly, (ii) at a fixed time interval following a preceding normal heartbeat, or (iii) by an independent oscillator that may or may not interact with the normal heartbeat. We compare the results of these three models and test their limitations to comprehensively simulate the statistical features of selected clinical records. This work introduces methods that can be used to test mathematical models of arrhythmogenesis and to develop a new understanding of underlying electrophysiologic mechanisms of cardiac arrhythmia.

  19. Regional wall motion abnormality in apical ballooning syndrome (Takotsubo/stress cardiomyopathy): importance of biplane left ventriculography for differentiating from spontaneously aborted anterior myocardial infarction.

    PubMed

    Patel, Sandeep M; Lennon, Ryan J; Prasad, Abhiram

    2012-04-01

    Understanding the precise distribution of the regional wall motion abnormality (RWMA) in apical ballooning syndrome (ABS) is important because the cardiomyopathy can mimic an acute anterior ST-elevation myocardial infarction (STEMI). The aim of the study was to quantify the severity and distribution of RWMA in ABS, compare it to anterior STEMI, and correlate with clinical features. RWMA (normal = 1, hypokinetic = 2, akinetic = 3) was quantified from the biplane left ventriculogram using a nine-segment model in 95 ABS and 17 anterior STEMI patients at the time of their presentation. Regional wall motion score index (RWMSI) was higher in ABS [2.1 (1.9, 2.1)] compared to anterior STEMI [2.0 (1.8, 2.0)], P = 0.024]. The region that most clearly differentiated ABS from anterior STEMI was the posterolateral segment (sensitivity 81% and specificity 100%) which was hypocontractile in 81% of ABS, but none of the STEMI patients (P < 0.001). RWMSI in ABS had a modest positive correlation with the troponin T levels (r = 0.23, P = 0.029). Patients with ABS with ST-segment elevation had the highest RWMSI [2.1(2.0, 2.2)], while those with non specific changes had the lowest [1.9 (1.8, 2.1)] (P = 0.007). In conclusion, patients with ABS have greater and more diffuse RWMA compared to anterior STEMI. The presence of systolic dysfunction in the posterolateral segment in the left anterior oblique projection of the left ventriculogram most accurately distinguishes ABS from an anterior STEMI highlighting the utility of biplane angiography for this purpose. The severity of RWMA correlates with the extent of troponin release and ECG abnormality.

  20. Effects of stress on memory in children and adolescents: testing causal connections.

    PubMed

    Quas, Jodi A; Rush, Elizabeth B; Yim, Ilona S; Nikolayev, Mariya

    2014-01-01

    Although a sizeable body of research has examined children's memory for stressful prior experiences, relatively few studies have experimentally manipulated stress during a to-be-remembered event to draw causal inferences about the effects of stress, especially across wide age ranges. We exposed children and adolescents to a more or a less arousing version of the Trier Social Stress Test-Modified (TSST-M), a widely used laboratory stress task. Two weeks later, we tested their memory for what happened. Interviewers behaved in a supportive or non-supportive manner. In adolescents, those who completed the high-arousal TSST-M provided fewer correct responses to recognition questions and fewer incorrect responses to misleading questions for which any answer would have been incorrect, compared to those who completed the lower-arousal TSST-M. Thus, arousal seemed to have reduced the adolescents' willingness to answer questions rather than having influenced their memory per se. In children, across TSST-M conditions, greater physiological arousal during the TSST-M predicted enhanced recall. Finally, interviewer support reduced the amount of factual information provided in free recall but increased correct responses to misleading questions. Results highlight the complex ways in which event stress and interviewer demeanour shape recounting of prior experiences across development.

  1. The effect of acute stress on subsequent neuropsychological test performance (2003).

    PubMed

    Hoffman, Richard; Al'Absi, Mustafa

    2004-06-01

    Acute mental stressors have been implicated as variables that may deleteriously affect neuropsychological test performance by increasing distractibility and decreasing working memory function. This study examined 25 subjects with no known neurological or psychiatric impairment on a brief battery of neuropsychological measures on alternate days following either rest or induced mental stress in a counterbalanced design. The test battery consisted of the Rey Auditory-Verbal Learning Test, the Rey Complex Figure, and three Wechsler Memory Scale-III subtests (Logical Memory, Digit Span, and Visual Memory Span). The Ss average age was 24.8 years (S.D. = 10.1) and average education was 15.0 years (S.D. = 1.6). The mental stressor employed was a videotaped public-speaking exercise that has been shown in previous work to induce negative mood, cardiovascular reactivity, and perceived mental stress. Ss demonstrated statistically significant (P < .05) increases in negative mood, heart rate, diastolic blood pressure, and systolic blood pressure as well as elevated cortisol concentration following induced stress, suggesting substantially increased adrenocortical reactivity and cardiovascular stress response. There were, however, no statistically significant differences in any of the neuropsychological measures when stress versus rest days were compared. The results suggest that acute mental stressors may have no measurable effect on subsequent performance on selected neuropsychological tests in a normal population. Further work is suggested to determine whether pre-existing anxiety-related psychopathology or pre-existing neurological compromise might interact with induced mental stress to cause decrements in neuropsychological test performance.

  2. Ascorbic acid protects against cadmium-induced endoplasmic reticulum stress and germ cell apoptosis in testes.

    PubMed

    Ji, Yan-Li; Wang, Zhen; Wang, Hua; Zhang, Cheng; Zhang, Ying; Zhao, Mei; Chen, Yuan-Hua; Meng, Xiu-Hong; Xu, De-Xiang

    2012-11-01

    Cadmium (Cd) is a testicular toxicant which induces endoplasmic reticulum (ER) stress and germ cell apoptosis in testes. This study investigated the effects of ascorbic acid on Cd-evoked ER stress and germ cell apoptosis in testes. Male mice were intraperitoneally injected with CdCl(2) (2.0 mg/kg). As expected, a single dose of Cd induced testicular germ cell apoptosis. Interestingly, Cd-triggered testicular germ cell apoptosis was almost completely inhibited in mice treated with ascorbic acid. Interestingly, ascorbic acid significantly attenuated Cd-induced upregulation of GRP78 in testes. In addition, ascorbic acid significantly attenuated Cd-triggered testicular IRE1α and eIF2α phosphorylation and XBP-1 activation, indicating that this antioxidant counteracts Cd-induced unfolded protein response (UPR) in testes. Finally, ascorbic acid significantly attenuated Cd-evoked upregulation of CHOP and JNK phosphorylation, two components in ER stress-mediated apoptotic pathway. In conclusion, ascorbic acid protects mice from Cd-triggered germ cell apoptosis via inhibiting ER stress and UPR in testes. PMID:22569276

  3. Thermal stress analysis of the NASA Dryden hypersonic wing test structure

    NASA Technical Reports Server (NTRS)

    Morris, Glenn

    1990-01-01

    Present interest in hypersonic vehicles has resulted in a renewed interest in thermal stress analysis of airframe structures. While there are numerous texts and papers on thermal stress analysis, practical examples and experience on light gage aircraft structures are fairly limited. A research program has been undertaken at General Dynamics to demonstrate the present state of the art, verify methods of analysis, gain experience in their use, and develop engineering judgement in thermal stress analysis. The approach for this project has been to conduct a series of analyses of this sample problem and compare analysis results with test data. This comparison will give an idea of how to use our present methods of thermal stress analysis, and how accurate we can expect them to be.

  4. Right Ventricular Dysfunction Secondary to Myocardial Ischemia Provoked by Stress Testing.

    PubMed

    Obeid, Anis I.; Battaglia, Joseph; Lozner, Eugene

    1998-07-01

    We present the cases of two patients, aged 59 and 85 years, who were evaluated with stress echocardiography for chest pain. Both patients developed dramatic echocardiographic findings consisting of severe right ventricular enlargement and hypokinesis, as well as enlargement of the right atrium at relatively low-level exercise. One patient collapsed with severe sinus bradycardia, junctional rhythm, ST elevation in the inferior leads, marked hypotension, and neck vein congestion. The other patient developed staggering and symptoms of hypoperfusion. In both patients, correction of critical proximal right coronary artery stenosis by angioplasty resulted in complete resolution of the right ventricular dysfunction on repeat stress testing. We conclude that in some patients, stress-induced myocardial ischemia may involve primarily the right ventricle with little or no evidence of ischemic changes in the left ventricle. An assessment of right ventricular function should be included in stress echocardiographic studies. PMID:11175063

  5. Study and Test of a New Bundle-Structure Riser Stress Monitoring Sensor Based on FBG.

    PubMed

    Xu, Jian; Yang, Dexing; Qin, Chuan; Jiang, Yajun; Sheng, Leixiang; Jia, Xiangyun; Bai, Yang; Shen, Xiaohong; Wang, Haiyan; Deng, Xin; Xu, Liangbin; Jiang, Shiquan

    2015-11-24

    To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the "HYSY-981" ocean oil drilling platform. No welding and pasting were used when the sensor was installed on risers. Therefore, the installation is convenient, reliable and harmless to risers. The continuous, reasonable, time-consistent data obtained indicates that the sensor worked normally under water. In all detailed working conditions, the test results show that the sensor can do well in reflecting stresses and bending moments both in and in magnitude. The measured maximum stress is 132.7 MPa, which is below the allowable stress. In drilling and testing conditions, the average riser stress was 86.6 MPa, which is within the range of the China National Offshore Oil Corporation (CNOOC) mechanical simulation results.

  6. Study and Test of a New Bundle-Structure Riser Stress Monitoring Sensor Based on FBG

    PubMed Central

    Xu, Jian; Yang, Dexing; Qin, Chuan; Jiang, Yajun; Sheng, Leixiang; Jia, Xiangyun; Bai, Yang; Shen, Xiaohong; Wang, Haiyan; Deng, Xin; Xu, Liangbin; Jiang, Shiquan

    2015-01-01

    To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the “HYSY-981” ocean oil drilling platform. No welding and pasting were used when the sensor was installed on risers. Therefore, the installation is convenient, reliable and harmless to risers. The continuous, reasonable, time-consistent data obtained indicates that the sensor worked normally under water. In all detailed working conditions, the test results show that the sensor can do well in reflecting stresses and bending moments both in and in magnitude. The measured maximum stress is 132.7 MPa, which is below the allowable stress. In drilling and testing conditions, the average riser stress was 86.6 MPa, which is within the range of the China National Offshore Oil Corporation (CNOOC) mechanical simulation results. PMID:26610517

  7. Quantification of Interfibrillar Shear Stress in Aligned Soft Collagenous Tissues via Notch Tension Testing

    NASA Astrophysics Data System (ADS)

    Szczesny, Spencer E.; Caplan, Jeffrey L.; Pedersen, Pal; Elliott, Dawn M.

    2015-10-01

    The mechanical function of soft collagenous tissues is largely determined by their hierarchical organization of collagen molecules. While collagen fibrils are believed to be discontinuous and transfer load through shearing of the interfibrillar matrix, interfibrillar shear stresses have never been quantified. Scaling traditional shear testing procedures down to the fibrillar length scale is impractical and would introduce substantial artifacts. Here, through the use of a novel microscopic variation of notch tension testing, we explicitly demonstrate the existence of interfibrillar shear stresses within tendon fascicles and provide the first measurement of their magnitude. Axial stress gradients along the sample length generated by notch tension testing were measured and used to calculate a value of 32 kPa for the interfibrillar shear stress. This estimate is comparable to the interfibrillar shear stress predicted by previous multiscale modeling of tendon fascicles, which supports the hypothesis that fibrils are discontinuous and transmit load through interfibrillar shear. This information regarding the structure-function relationships of tendon and other soft collagenous tissues is necessary to identify potential causes for tissue impairment with degeneration and provide the foundation for developing regenerative repair strategies or engineering biomaterials for tissue replacement.

  8. Study and Test of a New Bundle-Structure Riser Stress Monitoring Sensor Based on FBG.

    PubMed

    Xu, Jian; Yang, Dexing; Qin, Chuan; Jiang, Yajun; Sheng, Leixiang; Jia, Xiangyun; Bai, Yang; Shen, Xiaohong; Wang, Haiyan; Deng, Xin; Xu, Liangbin; Jiang, Shiquan

    2015-01-01

    To meet the requirements of riser safety monitoring in offshore oil fields, a new Fiber Bragg Grating (FBG)-based bundle-structure riser stress monitoring sensor has been developed. In cooperation with many departments, a 49-day marine test in water depths of 1365 m and 1252 m was completed on the "HYSY-981" ocean oil drilling platform. No welding and pasting were used when the sensor was installed on risers. Therefore, the installation is convenient, reliable and harmless to risers. The continuous, reasonable, time-consistent data obtained indicates that the sensor worked normally under water. In all detailed working conditions, the test results show that the sensor can do well in reflecting stresses and bending moments both in and in magnitude. The measured maximum stress is 132.7 MPa, which is below the allowable stress. In drilling and testing conditions, the average riser stress was 86.6 MPa, which is within the range of the China National Offshore Oil Corporation (CNOOC) mechanical simulation results. PMID:26610517

  9. Appropriate Use of Cardiac Stress Testing with Imaging: A Systematic Review and Meta-Analysis

    PubMed Central

    Ladapo, Joseph A.; Blecker, Saul; O'Donnell, Michael; Jumkhawala, Saahil A.; Douglas, Pamela S.

    2016-01-01

    Background Appropriate use criteria (AUC) for cardiac stress tests address concerns about utilization growth and patient safety. We systematically reviewed studies of appropriateness, including within physician specialties; evaluated trends over time and in response to AUC updates; and characterized leading indications for inappropriate/rarely appropriate testing. Methods We searched PubMed (2005–2015) for English-language articles reporting stress echocardiography or myocardial perfusion imaging (MPI) appropriateness. Data were pooled using random-effects meta-analysis and meta-regression. Results Thirty-four publications of 41,578 patients were included, primarily from academic centers. Stress echocardiography appropriate testing rates were 53.0% (95% CI, 45.3%–60.7%) and 50.9% (42.6%–59.2%) and inappropriate/rarely appropriate rates were 19.1% (11.4%–26.8%) and 28.4% (23.9%–32.8%) using 2008 and 2011 AUC, respectively. Stress MPI appropriate testing rates were 71.1% (64.5%–77.7%) and 72.0% (67.6%–76.3%) and inappropriate/rarely appropriate rates were 10.7% (7.2%–14.2%) and 15.7% (12.4%–19.1%) using 2005 and 2009 AUC, respectively. There was no significant temporal trend toward rising rates of appropriateness for stress echocardiography or MPI. Unclassified stress echocardiograms fell by 79% (p = 0.04) with updated AUC. There were no differences between cardiac specialists and internists. Conclusions Rates of appropriate use tend to be lower for stress echocardiography compared to MPI, and updated AUC reduced unclassified stress echocardiograms. There is no conclusive evidence that AUC improved appropriate use over time. Further research is needed to determine if integration of appropriateness guidelines in academic and community settings is an effective approach to optimizing inappropriate/rarely appropriate use of stress testing and its associated costs and patient harms. PMID:27536775

  10. The chloride stress-corrosion cracking behavior of stainless steels under different test methods

    SciTech Connect

    Jin, L.Z. . Dept. of Materials Science and Engineering)

    1994-12-01

    Chloride-induced stress-corrosion cracking (SCC) is one of the failure modes of stainless steels. Highly alloyed austenitic stainless steels S32654, S31254, and N08028, and duplex grades S32750 and S31803 possess much improved resistance to SCC compared with S30400 and S31600 steels. With the development of a database, SSData, experimental data collected from calcium chloride tests, autoclave tests, and drop evaporation tests were evaluated. Stress-corrosion cracking data generated by autoclave tests agreed well with the practical service conditions and can be used to discriminate alloys for SCC resistance in sodium chloride solution. Drop evaporation test data can be used in situations where evaporation may occur and cyclic loading may be involved. The SCC resistance of alloys under each method increased with increasing molybdenum equivalent Mo + 0.25Cr + 0.1Ni. For a given alloy, the testing result depends on the stress state and environment; different test methods can give different ranking orders concerning SCC resistance. The performance of duplex stainless steels in a chloride-containing environment at higher temperatures was not as good as expected when dynamic loading was involved.

  11. Transgenic mice with cardiac-specific expression of activating transcription factor 3, a stress-inducible gene, have conduction abnormalities and contractile dysfunction.

    PubMed

    Okamoto, Y; Chaves, A; Chen, J; Kelley, R; Jones, K; Weed, H G; Gardner, K L; Gangi, L; Yamaguchi, M; Klomkleaw, W; Nakayama, T; Hamlin, R L; Carnes, C; Altschuld, R; Bauer, J; Hai, T

    2001-08-01

    Activating transcription factor 3 (ATF3) is a member of the CREB/ATF family of transcription factors. Previously, we demonstrated that the expression of the ATF3 gene is induced by many stress signals. In this report, we demonstrate that expression of ATF3 is induced by cardiac ischemia coupled with reperfusion (ischemia-reperfusion) in both cultured cells and an animal model. Transgenic mice expressing ATF3 under the control of the alpha-myosin heavy chain promoter have atrial enlargement, and atrial and ventricular hypertrophy. Microscopic examination showed myocyte degeneration and fibrosis. Functionally, the transgenic heart has reduced contractility and aberrant conduction. Interestingly, expression of sorcin, a gene whose product inhibits the release of calcium from sarcoplasmic reticulum, is increased in these transgenic hearts. Taken together, our results indicate that expression of ATF3, a stress-inducible gene, in the heart leads to altered gene expression and impaired cardiac function. PMID:11485922

  12. Daily life stress and the cortisol awakening response: testing the anticipation hypothesis.

    PubMed

    Powell, Daniel J; Schlotz, Wolff

    2012-01-01

    The cortisol awakening response (CAR) is a distinct facet of the circadian cortisol rhythm associated with various health conditions and risk factors. It has repeatedly been suggested that the CAR could be a result of the anticipated demands of the upcoming day (stress anticipation) and could support coping with daily life stress. In a sample of 23 healthy participants CARs were assessed on two consecutive days by measures of salivary cortisol upon awakening (S1) and 30 and 45 minutes later, which were aggregated to the area under the curve increase (AUCI). Stress anticipation was assessed immediately after awakening. On the same days, daily life stress and distress were assessed six times per day based on a quasi-randomized design using handheld computers. Associations were tested by day using regression analysis and standard multilevel/mixed effects models for longitudinal data. The CAR AUCI moderated the effect of daily life stress on distress; higher CAR increases were associated with attenuated distress responses to daily life stress on both days (day 1: p = .039; day 2: p = .004) adjusted for age, gender, sleep quality, time of awakening and oral contraceptive use. Lagged-effects and redundancy models showed that this effect was not due to prior-day CAR increases but specific for same day CARs. On day 2, associations between daily life stress and distress were stronger when individuals showed a higher S1 cortisol level, but this effect was similar for S1 on day 1, and the day 2 effect of S1 became non-significant when S1 on day 1 was controlled. No associations were found between stress anticipation and CARs. Findings indicate that the CAR increase is associated with successful coping with same-day daily life stress.

  13. Testing the accelerating moment release (AMR) hypothesis in areas of high stress

    NASA Astrophysics Data System (ADS)

    Guilhem, Aurélie; Bürgmann, Roland; Freed, Andrew M.; Ali, Syed Tabrez

    2013-11-01

    Several retrospective analyses have proposed that significant increases in moment release occurred prior to many large earthquakes of recent times. However, the finding of accelerating moment release (AMR) strongly depends on the choice of three parameters: (1) magnitude range, (2) area being considered surrounding the events and (3) the time period prior to the large earthquakes. Consequently, the AMR analysis has been criticized as being a posteriori data-fitting exercise with no new predictive power. As AMR has been hypothesized to relate to changes in the state of stress around the eventual epicentre, we compare here AMR results to models of stress accumulation in California. Instead of assuming a complete stress drop on all surrounding fault segments implied by a back-slip stress lobe method, we consider that stress evolves dynamically, punctuated by the occurrence of earthquakes, and governed by the elastic and viscous properties of the lithosphere. We study the seismicity of southern California and extract events for AMR calculations following the systematic approach employed in previous studies. We present several sensitivity tests of the method, as well as grid-search analyses over the region between 1955 and 2005 using fixed magnitude range, radius of the search area and period of time. The results are compared to the occurrence of large events and to maps of Coulomb stress changes. The Coulomb stress maps are compiled using the coseismic stress from all M > 7.0 earthquakes since 1812, their subsequent post-seismic relaxation, and the interseismic strain accumulation. We find no convincing correlation of seismicity rate changes in recent decades with areas of high stress that would support the AMR hypothesis. Furthermore, this indicates limited utility for practical earthquake hazard analysis in southern California, and possibly other regions.

  14. ST-Elevation Myocardial Infarction after Pharmacologic Persantine Stress Test in a Patient with Wellens' Syndrome

    PubMed Central

    Alattar, Fady; Koneru, Jayanth; Shamoon, Fayez

    2014-01-01

    Wellens' syndrome, also known as LAD coronary T-wave inversion syndrome, is a characteristic ECG pattern that highly suggests critical stenosis of the proximal left anterior descending (LAD) coronary artery. 75% of patients with this finding go on to develop acute anterior wall myocardial infarction within one week unless prevented by early intervention on the culprit lesion. Most instances of ST-elevation occurring during cardiac stress testing have been observed with exercise, with only seven cases reported in the literature with pharmacologic stress. We present a case of a patient with no known cardiac disease who presented with chest pain and an ECG consistent with Wellens' syndrome that developed an acute anterior wall ST-elevation myocardial infarction after pharmacologic stress test. PMID:25161778

  15. Chronic sensory stroke with and without central pain is associated with bilaterally distributed sensory abnormalities as detected by quantitative sensory testing.

    PubMed

    Krause, Thomas; Asseyer, Susanna; Geisler, Frederik; Fiebach, Jochen B; Oeltjenbruns, Jochen; Kopf, Andreas; Villringer, Kersten; Villringer, Arno; Jungehulsing, Gerhard J

    2016-01-01

    Approximately 20% of patients suffering from stroke with pure or predominant sensory symptoms (referred to as sensory stroke patients) develop central poststroke pain (CPSP). It is largely unknown what distinguishes these patients from those who remain pain free. Using quantitative sensory testing (QST), we analyzed the somatosensory profiles of 50 patients with chronic sensory stroke, of which 25 suffered from CPSP. As compared with reference data from healthy controls, patients with CPSP showed alterations of thermal and mechanical thresholds on the body area contralateral to their stroke (P < 0.01). Patients with sensory stroke but without CPSP (non-pain sensory stroke [NPSS] patients) exhibited similar albeit less pronounced contralesional changes. Paradoxical heat sensation (PHS) and dynamic mechanical allodynia (DMA) showed higher values in CPSP, and an elevated cold detection threshold (CDT) was seen more often in CPSP than in patients with NPSS (P < 0.05). In patients with CPSP, changes in CDT, PHS, dynamic mechanical allodynia, and temporal pain summation (wind-up ratio) each correlated with the presence of pain (P < 0.05). On the homologous ipsilesional body area, both patient groups showed additional significant abnormalities as compared with the reference data, which strongly resembled the contralesional changes. In summary, our analysis reveals that CPSP is associated with impaired temperature perception and positive sensory signs, but differences between patients with CPSP and NPSS are subtle. Both patients with CPSP and NPSS show considerable QST changes on the ipsilesional body side. These results are in part paralleled by recent findings of bilaterally spread cortical atrophy in CPSP and might reflect chronic maladaptive cortical plasticity, particularly in patients with CPSP.

  16. Development of a standardized battery of performance tests for the assessment of noise stress effects

    NASA Technical Reports Server (NTRS)

    Theologus, G. C.; Wheaton, G. R.; Mirabella, A.; Brahlek, R. E.

    1973-01-01

    A set of 36 relatively independent categories of human performance were identified. These categories encompass human performance in the cognitive, perceptual, and psychomotor areas, and include diagnostic measures and sensitive performance metrics. Then a prototype standardized test battery was constructed, and research was conducted to obtain information on the sensitivity of the tests to stress, the sensitivity of selected categories of performance degradation, the time course of stress effects on each of the selected tests, and the learning curves associated with each test. A research project utilizing a three factor partially repeated analysis of covariance design was conducted in which 60 male subjects were exposed to variations in noise level and quality during performance testing. Effects of randomly intermittent noise on performance of the reaction time tests were observed, but most of the other performance tests showed consistent stability. The results of 14 analyses of covariance of the data taken from the performance of the 60 subjects on the prototype standardized test battery provided information which will enable the final development and test of a standardized test battery and the associated development of differential sensitivity metrics and diagnostic classificatory system.

  17. High-Stakes Testing and Its Relationship to Stress Levels of Secondary Teachers

    ERIC Educational Resources Information Center

    Christian, Sonya Colman

    2010-01-01

    This study investigated the relationship between high-stakes testing and the stress levels of secondary teachers in Jackson's Jackson Public School District. The independent variables of age, gender, subject taught, teaching experience, degree and school level were used to determine the differences of the various groups. A survey was piloted and…

  18. Economic Distress and Intimate Violence: Testing Family Stress and Resources Theories.

    ERIC Educational Resources Information Center

    Fox, Greer Litton; Benson, Michael L.; DeMaris, Alfred A.; Van Wyk, Judy

    2002-01-01

    Tests hypotheses shaped by family stress and resource theories about the impact of household economic indicators on the risk of violence against women in intimate relationships. Measures of employment status, job conditions, and economic well-being for male and female partners are examined with logistic regression analyses as predictors of the…

  19. Simulated Service and Stress Corrosion Cracking Testing for Friction Stir Welded Spun Formed Domes

    NASA Technical Reports Server (NTRS)

    Stewart, Thomas J.; Torres, Pablo D.; Caratus, Andrei A.; Curreri, Peter A.

    2010-01-01

    Simulated service testing (SST) development was required to help qualify a new 2195 aluminum lithium (Al-Li) alloy spin forming dome fabrication process for the National Aeronautics and Space Administration (NASA) Exploration Development Technology Program. The application for the technology is to produce high strength low weight tank components for NASA s next generation launch vehicles. Since plate material is not currently manufactured large enough to fabricate these domes, two plates are joined by means of friction stir welding. The plates are then pre-contour machined to near final thicknesses allowing for a thicker weld land and anticipating the level of stretch induced by the spin forming process. The welded plates are then placed in a spin forming tool and hot stretched using a trace method producing incremental contours. Finally the dome receives a room temperature contour stretch to final dimensions, heat treatment, quenching, and artificial aging to emulate a T-8 condition of temper. Stress corrosion cracking (SCC) tests were also performed by alternate immersion in a sodium chloride (NaCl) solution using the typical double beam assembly and with 4-point loaded specimens and use of bent-beam stress-corrosion test specimens under alternate immersion conditions. In addition, experiments were conducted to determine the threshold stress intensity factor for SCC (K(sub ISCC)) which to our knowledge has not been determined previously for Al-Li 2195 alloy. The successful simulated service and stress corrosion testing helped to provide confidence to continue to Ares 1 scale dome fabrication

  20. Relationship between Academic Stress and Suicidal Ideation: Testing for Depression as a Mediator Using Multiple Regression

    ERIC Educational Resources Information Center

    Ang, Rebecca P.; Huan, Vivien S.

    2006-01-01

    Relations among academic stress, depression, and suicidal ideation were examined in 1,108 Asian adolescents 12-18 years old from a secondary school in Singapore. Using Baron and Kenny's [J Pers Soc Psychol 51:1173-1192, 1986] framework, this study tested the prediction that adolescent depression mediated the relationship between academic stress…

  1. Testing a Theoretical Model of the Stress Process in Alzheimer's Caregivers with Race as a Moderator

    ERIC Educational Resources Information Center

    Hilgeman, Michelle M.; Durkin, Daniel W.; Sun, Fei; DeCoster, Jamie; Allen, Rebecca S.; Gallagher-Thompson, Dolores; Burgio, Louis D.

    2009-01-01

    Purpose: The primary aim of this study was to test the stress process model (SPM; Pearlin, Mullan, Semple, & Skaff, 1990) in a racially diverse sample of Alzheimer's caregivers (CGs) using structural equation modeling (SEM) and regression techniques. A secondary aim was to examine race or ethnicity as a moderator of the relation between latent…

  2. Emotional-volitional components of operator reliability. [sensorimotor function testing under stress

    NASA Technical Reports Server (NTRS)

    Mileryan, Y. A.

    1975-01-01

    Sensorimotor function testing in a tracking task under stressfull working conditions established a psychological characterization for a successful aviation pilot: Motivation significantly increased the reliability and effectiveness of their work. Their acitivities were aimed at suppressing weariness and the feeling of fear caused by the stress factors; they showed patience, endurance, persistence, and a capacity for lengthy volitional efforts.

  3. Diode step stress testing program for JANTX1N2989B

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The effect of power/temperature step stress when applied to the zener diode JANTX2N2989 manufactured by Siemens and General Semiconductor is reported. A total of 48 samples from each manufacturer was submitted to the process. In addition, two control sample units were maintained for verification of the electrical parameteric testing.

  4. Economic Crisis and Marital Problems in Turkey: Testing the Family Stress Model

    ERIC Educational Resources Information Center

    Aytac, Isik A.; Rankin, Bruce H.

    2009-01-01

    This paper applied the family stress model to the case of Turkey in the wake of the 2001 economic crisis. Using structural equation modeling and a nationally representative urban sample of 711 married women and 490 married men, we tested whether economic hardship and the associated family economic strain on families resulted in greater marital…

  5. Accelerated Stress Testing of Thin-Film Modules with SnO2:F Transparent Conductors

    SciTech Connect

    Osterwald, C. R.; McMahon, T. J.; del Cueto, J. A.; Adelstein, J.; Puett, J.

    2003-05-01

    This paper reviews a testing program conducted at NREL for the past two years that applied voltage, water vapor, and light stresses to thin-film photovoltaic (PV) modules with SnO2:F transparent conducting oxides (TCOs) deposited on soda-lime glass superstrates. Electrochemical corrosion at the glass-TCO interface was observed to result in delamination of the thin-film layers. Experimental testing was directed toward accelerating the corrosion and understanding the nature of the resulting damage.

  6. Update on pharmacological cardiac stress testing: efficacy, risk stratification and patient selection.

    PubMed

    Blankstein, Ron; Cannon, Christopher; Udelson, James

    2014-11-01

    Despite greater control of risk factors and improved treatments, coronary heart disease (CHD) remains a significant cause of mortality with 1 in every 4 deaths in the United States due to this disorder.(1) Cardiac stress tests have long been one of the most often utilized testing modalities used to identify patients suspected of having CHD, specifically coronary artery disease (CAD). These tests allow for noninvasive assessment of the coronary circulation and its ability to augment flow in response to physiologic demand. As with any diagnostic testing however, potential health risks as well as the financial burden of cardiovascular stress testing, must be weighed against the benefits and utility of the data procured. Given the rapidly evolving field of cardiac stress testing with respect to new risk stratification guidelines, new agents, and new assessment methods, it is difficult for physicians to remain up to date on the latest research and the benefits and risks of different testing modalities. A recent survey of primary care physicians and cardiologists conducted by the Elsevier Office of Continuing Medical Education found that approximately one-quarter of the cardiologists and primary care physicians surveyed do not feel confident identifying the factors which should be considered before ordering a cardiac stress test as part of pre-operative screening for a patient. Additionally, this survey also reported that primary care physicians reported a high degree of confidence in ordering the appropriate cardiac screening tests for patients yet, cardiologists reported that they frequently/somewhat frequently felt the need to change the test ordered by the internist. This educational intervention focuses on patient selection, exercise vs. pharmacologic stress testing, pharmacologic agents, and the importance of patient and doctor communication in ensuring the right test is recommended for the right patient. This CME Multimedia Activity is also available through the

  7. The early identification of psychosis: can lessons be learnt from cardiac stress testing?

    PubMed

    Gupta, Swapnil; Ranganathan, Mohini; D'Souza, Deepak Cyril

    2016-01-01

    Psychotic disorders including schizophrenia are amongst the most debilitating psychiatric disorders. There is an urgent need to develop methods to identify individuals at risk with greater precision and as early as possible. At present, a prerequisite for a diagnosis of schizophrenia is the occurrence of a psychotic episode. Therefore, attempting to detect schizophrenia on the basis of psychosis is analogous to diagnosing coronary artery disease (CAD) after the occurrence of a myocardial infarction (MI). The introduction of cardiac stress testing (CST) has revolutionized the detection of CAD and the prevention and management of angina and MI. In this paper, we attempt to apply lessons learnt from CST to the early detection of psychosis by proposing the development of an analogous psychosis stress test. We discuss in detail the various parameters of a proposed psychosis stress test including the choice of a suitable psychological or psychopharmacological "stressor," target population, outcome measures, safety of the approach, and the necessary evolution of test to become clinically informative. The history of evolution of CST may guide the development of a similar approach for the detection and management of psychotic disorders. The initial development of a test to unmask latent risk for schizophrenia will require the selection of a suitable and safe stimulus and the development of outcome measures as a prelude to testing in populations with a range of risk to determine predictive value. The use of CST in CAD offers the intriguing possibility that a similar approach may be applied to the detection and management of schizophrenia.

  8. Spirometric abnormalities among welders

    SciTech Connect

    Rastogi, S.K.; Gupta, B.N.; Husain, T.; Mathur, N.; Srivastava, S. )

    1991-10-01

    A group of manual welders age group 13-60 years having a mean exposure period of 12.4 {plus minus} 1.12 years were subjected to spirometry to evaluate the prevalence of spirometric abnormalities. The welders showed a significantly higher prevalence of respiratory impairment than that observed among the unexposed controls as a result of exposure to welding gases which comprised fine particles of lead, zinc, chromium, and manganese. This occurred despite the lower concentration of the pollutants at the work place. In the expose group, the smoking welders showed a prevalence of respiratory impairment significantly higher than that observed in the nonsmoking welders. The results of the pulmonary function tests showed a predominantly restrictive type of pulmonary impairment followed by a mixed ventilatory defect among the welders. The effect of age on pulmonary impairment was not discernible. Welders exposed for over 10 years showed a prevalence of respiratory abnormalities significantly higher than those exposed for less than 10 years. Smoking also had a contributory role.

  9. Comparison of online and offline tests in LED accelerated reliability tests under temperature stress.

    PubMed

    Ke, Hong-Liang; Jing, Lei; Gao, Qun; Wang, Yao; Hao, Jian; Sun, Qiang; Xu, Zhi-Jun

    2015-11-20

    Accelerated aging tests are the main method used in the evaluation of LED reliability, and can be performed in either online or offline modes. The goal of this study is to provide the difference between the two test modes. In the experiments, the sample is attached to different heat sinks to acquire the optical parameters under different junction temperatures of LEDs. By measuring the junction temperature in the aging process (Tj1), and the junction temperature in the testing process (Tj2), we achieve consistency with an online test of Tj1 and Tj2 and a difference with an offline test of Tj1 and Tj2. Experimental results show that the degradation rate of the luminous flux rises as Tj2 increases, which yields a difference of projected life L(70%) of 8% to 13%. For color shifts over 5000 h of aging, the online test shows a larger variation of the distance from the Planckian locus, about 40% to 50% more than the normal test at an ambient temperature of 25°C. PMID:26836556

  10. Relation of Risk of Atrial Fibrillation With Systolic Blood Pressure Response During Exercise Stress Testing (from the Henry Ford ExercIse Testing Project).

    PubMed

    O'Neal, Wesley T; Qureshi, Waqas T; Blaha, Michael J; Ehrman, Jonathan K; Brawner, Clinton A; Nasir, Khurram; Al-Mallah, Mouaz H

    2015-12-15

    Decreases in systolic blood pressure during exercise may predispose to arrhythmias such as atrial fibrillation (AF) because of underlying abnormal autonomic tone. We examined the association between systolic blood pressure response and incident AF in 57,442 (mean age 54 ± 13 years, 47% women, and 29% black) patients free of baseline AF who underwent exercise treadmill stress testing from the Henry Ford ExercIse Testing project. Exercise systolic blood pressure response was examined as a categorical variable across clinically relevant categories (>20 mm Hg: referent; 1 to 20 mm Hg, and ≤0 mm Hg) and per 1-SD decrease. Cox regression, adjusting for demographics, cardiovascular risk factors, medications, history of coronary heart disease, history of heart failure, and metabolic equivalent of task achieved, was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between systolic blood pressure response and incident AF. Over a median follow-up of 5.0 years, a total of 3,381 cases (5.9%) of AF were identified. An increased risk of AF was observed with decreasing systolic blood pressure response (>20 mm Hg: HR 1.0, referent; 1 to 20 mm Hg: HR 1.09, 95% CI 0.99, 1.20; ≤0 mm Hg: HR 1.22, 95% CI 1.06 to 1.40). Similar results were obtained per 1-SD decrease in systolic blood pressure response (HR 1.08, 95% CI 1.04 to 1.12). The results were consistent when stratified by age, sex, race, hypertension, and coronary heart disease. In conclusion, our results suggest that a decreased systolic blood pressure response during exercise may identify subjects who are at risk for developing AF. PMID:26603907

  11. Longitudinal and Integrative Tests of Family Stress Model Effects on Mexican-Origin Adolescents

    PubMed Central

    White, Rebecca M. B.; Liu, Yu; Nair, Rajni L.; Tein, Jenn-Yun

    2015-01-01

    The family stress model represents a common framework through which to examine the effects of environmental stressors on adolescent adjustment. The model suggests that economic and neighborhood stressors influence youth adjustment via disruptions to parenting. Incorporating integrative developmental theory, we examined the degree to which parents’ cultural value orientations mitigated the effects of stressors on parenting disruptions and the degree to which environmental adversity qualified the effect of parenting on adolescent adjustment. We tested the hypothesized Integrative Family Stress Model longitudinally in a sample of mother-youth dyads (N = 749) and father-youth dyads (N = 467) from Mexican origin families, across three times points spanning early to middle adolescence. Providing the first longitudinal evidence of family stress mediated effects, mothers’ perceptions of economic pressure were associated with increases in adolescent externalizing symptoms five years later via intermediate increases in harsh parenting. The remaining findings supported the notion that integrative developmental theory can inform family stress model hypothesis testing that is culturally and contextually relevant for wide range of diverse families and youth. For example, fathers’ perceptions of economic pressure and neighborhood danger had important implications for adolescent internalizing, via reductions in paternal warmth, but only at certain levels of neighborhood adversity. Mothers’ familism value orientations mitigated the effects of economic pressure on maternal warmth, protecting their adolescents from experiencing developmental costs associated with environmental stressors. Results are discussed in terms of identifying how integrative developmental theory intersects with the family stress model to set diverse youth on different developmental pathways. PMID:25751100

  12. Longitudinal and integrative tests of family stress model effects on Mexican origin adolescents.

    PubMed

    White, Rebecca M B; Liu, Yu; Nair, Rajni L; Tein, Jenn-Yun

    2015-05-01

    The family stress model represents a common framework through which to examine the effects of environmental stressors on adolescent adjustment. The model suggests that economic and neighborhood stressors influence youth adjustment via disruptions to parenting. Incorporating integrative developmental theory, we examined the degree to which parents' cultural value orientations mitigated the effects of stressors on parenting disruptions and the degree to which environmental adversity qualified the effect of parenting on adolescent adjustment. We tested the hypothesized integrative family stress model longitudinally in a sample of mother-youth dyads (N = 749) and father-youth dyads (N = 467) from Mexican origin families, across 3 times points spanning early to middle adolescence. Providing the first longitudinal evidence of family stress mediated effects, mothers' perceptions of economic pressure were associated with increases in adolescent externalizing symptoms 5 years later via intermediate increases in harsh parenting. The remaining findings supported the notion that integrative developmental theory can inform family stress model hypothesis testing that is culturally and contextually relevant for a wide range of diverse families and youth. For example, fathers' perceptions of economic pressure and neighborhood danger had important implications for adolescent internalizing, via reductions in paternal warmth, but only at certain levels of neighborhood adversity. Mothers' familism value orientations mitigated the effects of economic pressure on maternal warmth, protecting their adolescents from experiencing developmental costs associated with environmental stressors. Results are discussed in terms of identifying how integrative developmental theory intersects with the family stress model to set diverse youth on different developmental pathways. PMID:25751100

  13. Stress Free Temperature Testing and Calculations on Out-of-Autoclave Composites

    NASA Technical Reports Server (NTRS)

    Cox, Sarah B.; Tate, LeNetra C.; Danley, Susan E.; Sampson, Jeffrey W.; Taylor, Brian J.; Sutter, James K.; Miller, Sandi G.

    2013-01-01

    Future launch vehicles will require the incorporation of large composite parts that will make up primary and secondary components of the vehicle. NASA has explored the feasibility of manufacturing these large components using Out-of-Autoclave impregnated carbon fiber composite systems through many composites development projects. Most recently, the Composites for Exploration Project has been looking at the development of a 10 meter diameter fairing structure, similar in size to what will be required for a heavy launch vehicle. The development of new material systems requires the investigation of the material properties and the stress in the parts. Residual stress is an important factor to incorporate when modeling the stresses that a part is undergoing. Testing was performed to verify the stress free temperature with two-ply asymmetric panels. A comparison was done between three newly developed out of autoclave IM7/Bismaleimide (BMI) systems. This paper presents the testing results and the analysis performed to determine the stress free temperature of the materials

  14. Testing the Adaptation to Poverty-Related Stress Model: Predicting Psychopathology Symptoms in Families Facing Economic Hardship

    ERIC Educational Resources Information Center

    Wadsworth, Martha E.; Raviv, Tali; Santiago, Catherine DeCarlo; Etter, Erica M.

    2011-01-01

    This study tested the Adaptation to Poverty-related Stress Model and its proposed relations between poverty-related stress, effortful and involuntary stress responses, and symptoms of psychopathology in an ethnically diverse sample of low-income children and their parents. Prospective Hierarchical Linear Modeling analyses conducted with 98…

  15. Test Review: Abidin, R. R. (2012) "Parenting Stress Index, Fourth Edition" ("PSI-4"). Lutz, Florida: Psychological Assessment Resources

    ERIC Educational Resources Information Center

    Johnson, Alyce O.

    2015-01-01

    The "Parenting Stress Index, Fourth Edition" (PSI-4) is a 120-item measure used to explore parental stress levels considering a parent's relationship with one of his or her children between the ages of 1 month and 12 years. The main purpose of the test is to define these stress levels and from where they originate in order to identify…

  16. Summary of tectonic and structural evidence for stress orientation at the Nevada Test Site

    USGS Publications Warehouse

    Carr, Wilfred James

    1974-01-01

    A tectonic synthesis of the NTS (Nevada Test Site) region, when combined with seismic data and a few stress and strain measurements, suggests a tentative model for stress orientation. This model proposes that the NTS is undergoing extension in a N. 50 ? W.-S. 50 ? E. direction coincident with the minimum principal stress direction. The model is supported by (1) a tectonic similarity between a belt of NTS Quaternary faulting and part of the Nevada-California seismic belt, for which northwest-southeast extension has been suggested; (2) historic northeast- trending natural- and explosion-produced fractures in the NTS; (3) the virtual absence in the NTS of northwest-trending Quaternary faults; (4) the character of north-trending faults and basin configuration in the Yucca Flat area, which suggest a component of right-lateral displacement and post-10 m.y. (million year) oblique separation of the sides of the north-trending depression; (5) seismic evidence suggesting a north- to northwest-trending tension axis; (6) strain measurements, which indicate episodes of northwest-southeast extension within a net northeast-southwest compression; (7) a stress estimate based on tectonic cracking that indicates near-surface northwest-southeast-directed tension, and two stress measurements indicating an excess (tectonic) maximum principal compressive stress in a northeast-southwest direction at depths of about 1,000 feet (305 m); and (8) enlargement of some drill holes in Yucca Flat in a northwest-southeast direction. It is inferred that the stress episode resulting in the formation of deep alluvium-filled trenches began somewhere between 10 and possibly less than 4 m.y. ago in the NTS and is currently active. In the Walker Lane of western Nevada, crystallization of plutons associated with Miocene volcanism may have increased the competency and thickness of the crust and its ability to propagate stress, thereby modulating the frequency (spacing) of basin-range faults.

  17. The Trier Social Stress Test for Groups (TSST-G): A new research tool for controlled simultaneous social stress exposure in a group format.

    PubMed

    von Dawans, Bernadette; Kirschbaum, Clemens; Heinrichs, Markus

    2011-05-01

    Psychological stress is an ubiquitous challenge across human cultures affecting mental and physical health. Recent evidence indicates that performance tasks combining elements of socio-evaluative threat and uncontrollability elicit reliable stress responses. The Trier Social Stress Test (TSST) is the most frequently used psychological protocol in stress research; however, to date it has only been available in a single-subject version. In particular, there is an increasing need in several emerging research fields such as stress research or social neurosciences for a standardized research tool to expose relatively large groups of subjects to controlled simultaneous stress. In search of a laboratory stressor that allows simultaneous stress exposure in a group format, we exposed a total of 25 healthy male participants to the Trier Social Stress Test for Groups (TSST-G; public speaking and mental arithmetic tasks in front of a panel of two evaluators in groups of six participants) and a specific control condition. Results showed that the TSST-G induced significant increases in cortisol, heart rate, and psychological stress responses. The TSST-G provides a novel, effective, and economical protocol for experimental paradigms requiring simultaneous stress induction in multiple participants.

  18. Common toad Rhinella arenarum (Hensel, 1867) and its importance in assessing environmental health: test of micronuclei and nuclear abnormalities in erythrocytes.

    PubMed

    Pollo, Favio E; Bionda, Clarisa L; Salinas, Zulma A; Salas, Nancy E; Martino, Adolfo L

    2015-09-01

    Anthropogenic activities may generate significant changes in the integrity of aquatic ecosystems, so long-term monitoring of populations that inhabit them is crucial. Counting micronucleated erythrocytes (MN) and erythrocytic nuclear abnormalities (ENA) in peripheral blood is a widely used method for detecting chromosomal damage due to chemical agents in the water. We analyzed MN and ENA frequency in blood obtained from the common toad Rhinella arenarum populations in sites with different degrees of environmental degradation. The results of this study indicate that there is an association between the frequency of micronuclei and nuclear abnormalities and the degree of environmental alteration recorded for the sites studied.

  19. Abnormal behavior of threshold voltage shift in bias-stressed a-Si:H thin film transistor under extremely high intensity illumination.

    PubMed

    Han, Sang Youn; Park, Kyung Tea; Kim, Cheolkyu; Jeon, Sanghyun; Yang, Sung-Hoon; Kong, Hyang-Shik

    2015-07-22

    We report on the unusual behavior of threshold voltage turnaround in a hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) when biased under extremely high intensity illumination. The threshold voltage shift changes from negative to positive gate bias direction after ∼30 min of bias stress even when the negative gate bias stress is applied under high intensity illumination (>400 000 Cd/cm(2)), which has not been observed in low intensity (∼6000 Cd/cm(2)). This behavior is more pronounced in a low work function gate metal structure (Al: 4.1-4.3 eV), compared to the high work function of Cu (4.5-5.1 eV). Also this is mainly observed in shorter wavelength of high photon energy illumination. However, this behavior is effectively prohibited by embedding the high energy band gap (∼8.6 eV) of SiOx in the gate insulator layer. These imply that this behavior could be originated from the injection of electrons from gate electrode, transported and trapped in the electron trap sites of the SiNx/a-Si:H interface, which causes the shift of threshold voltage toward positive gate bias direction. The results reported here can be applicable to the large-sized outdoor displays which are usually exposed to the extremely high intensity illumination.

  20. Phospholipase D-mediated hypersensitivity at central synapses is associated with abnormal behaviours and pain sensitivity in rats exposed to prenatal stress.

    PubMed

    Sun, Liting; Gooding, Hayley L; Brunton, Paula J; Russell, John A; Mitchell, Rory; Fleetwood-Walker, Sue

    2013-11-01

    Adverse events at critical stages of development can lead to lasting dysfunction in the central nervous system (CNS). To seek potential underlying changes in synaptic function, we used a newly developed protocol to measure alterations in receptor-mediated Ca(2+) fluorescence responses of synaptoneurosomes, freshly isolated from selected regions of the CNS concerned with emotionality and pain processing. We compared adult male controls and offspring of rats exposed to social stress in late pregnancy (prenatal stress, PS), which showed programmed behavioural changes indicating anxiety, anhedonia and pain hypersensitivity. We found corresponding increases, in PS rats compared with normal controls, in responsiveness of synaptoneurosomes from frontal cortex to a glutamate receptor (GluR) agonist, and from spinal cord to activators of nociceptive afferents. Through a combined pharmacological and biochemical strategy, we found evidence for a role of phospholipase D1 (PLD1)-mediated signalling, that may involve 5-HT2A receptor (5-HT2AR) activation, at both levels of the nervous system. These changes might participate in underpinning the enduring alterations in behaviour induced by PS. PMID:23932932

  1. Cocoa protective effects against abnormal fat storage and oxidative stress induced by a high-fat diet involve PPARα signalling activation.

    PubMed

    Fidaleo, Marco; Fracassi, Anna; Zuorro, Antonio; Lavecchia, Roberto; Moreno, Sandra; Sartori, Claudia

    2014-11-01

    A high-fat (HF) diet increases lipid storage and oxidative stress in mouse liver and this process seems to be mediated by Peroxisome Proliferator-Activated Receptor α (PPARα). In this study we evaluated the protective effect of cocoa against hepatic steatosis induced by a HF diet. The HF diet down-regulated PPARα expression and turned off PPARα-signalling, deregulated the β-oxidation (β-Ox) system and catalase (CAT) activity, increased fat storage, reduced expression of enzymatic activity involved in oxidative defence in the liver and doubled the weight gain per calorie consumed compared to animals under the normal diet. In contrast, cocoa improved hepatic β-Ox, activated PPARα-signalling and up-regulated both gene and protein expression of SOD1. Moreover, when co-administered with the HF diet, cocoa treatment counteracted lipid storage in the liver, improved the lipid-metabolizing activity and oxidative stress defences and normalized the weight gain per calorie consumed.

  2. The effect of Brazilian Propolis on leg health in broilers reared under heat stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exposing broiler chickens to heat stress increases leg abnormalities and Gait Score, also it reduced the time of Latency to Lie Test. This experiment was conducted to examine the effect of dietary supplemention with green Brazilian propolis on Latency to Lie Test for leg strength and leg abnormaliti...

  3. A microfluidic platform for rapid, stress-induced antibiotic susceptibility testing of Staphylococcus aureus

    PubMed Central

    Kalashnikov, Maxim; Lee, Jean C.; Campbell, Jennifer; Sharon, Andre; Sauer-Budge, Alexis F.

    2012-01-01

    The emergence and spread of bacterial resistance to ever increasing classes of antibiotics intensifies the need for fast phenotype-based clinical tests for determining antibiotic susceptibility. Standard susceptibility testing relies on the passive observation of bacterial growth inhibition in the presence of antibiotics. In this paper, we present a novel microfluidic platform for antibiotic susceptibility testing basedon stress-activation of biosynthetic pathways that are the primary targets of antibiotics. We chose Staphylococcus aureus as a model system due to its clinical importance, and we selected bacterial cell wall biosynthesis as the primary target of both stress and antibiotic. Enzymatic and mechanical stresses were used to damage the bacterial cell wall, and a β-lactam antibiotic interfered with the repair process, resulting in rapid cell death of strains that harbor no resistance mechanism. In contrast, resistant bacteria remained viable under the assay conditions. Bacteria, covalently-bound to the bottom of the microfluidic channel, were subjected to mechanical shear stress created by flowing culture media through the microfluidic channel and to enzymatic stress with sub-inhibitory concentrations of the bactericidal agent lysostaphin. Bacterial cell death was monitored via fluorescence using the Sytox Green dead cell stain, and rates of killing were measured for the bacterial samples in the presence and absence of oxacillin. Using model susceptible (Sanger 476) and resistant (MW2) S. aureus strains, a metric was established to separate susceptible and resistant staphylococci based on normalized fluorescence values after 60 minutes of exposure to stress and antibiotic. Because this groundbreaking approach is not based on standard methodology, it circumvents the need for minimum inhibitory concentration (MIC) measurements and long wait times. We demonstrate the successful development of a rapid microfluidic-based and stress-activated antibiotic

  4. Stress testing for risk stratification of patients with low to moderate probability of acute cardiac ischemia.

    PubMed

    Chandra, A; Rudraiah, L; Zalenski, R J

    2001-02-01

    In summary, this article focused on the use of stress testing to risk-stratify patients at the conclusion of their emergency evaluation for ACI. As discussed, those patients in the probably not ACI category require additional risk stratification prior to discharge. It should be kept in mind that patients in this category are heterogeneous, containing subgroups at both higher and lower risk of ACI and cardiac events. The patients with lower pretest probability for ACI may only need exercise testing in the ED. Patients with higher pretest probability should undergo myocardial perfusion or echocardiographic stress testing to maximize diagnostic and prognostic information. Prognostic information is the key to provocative testing in the ED. Prognostic information is the component that will help emergency physicians identify the patients who may be discharged home safely without having to worry about a 6% annual cardiac death rate and a 10% overall death rate over the next 30 months. Stress testing provides this key prognostic data, and it can be obtained in short-stay chest pain observation units in a safe, timely, and cost-effective fashion. PMID:11214405

  5. Stress corrosion cracking tests on high-level-waste container materials in simulated tuff repository environments

    SciTech Connect

    Abraham, T.; Jain, H.; Soo, P.

    1986-06-01

    Types 304L, 316L, and 321 austenitic stainless steel and Incoloy 825 are being considered as candidate container materials for emplacing high-level waste in a tuff repository. The stress corrosion cracking susceptibility of these materials under simulated tuff repository conditions was evaluated by using the notched C-ring method. The tests were conducted in boiling synthetic groundwater as well as in the steam/air phase above the boiling solutions. All specimens were in contact with crushed Topopah Spring tuff. The investigation showed that microcracks are frequently observed after testing as a result of stress corrosion cracking or intergranular attack. Results showing changes in water chemistry during test are also presented.

  6. A prototype gas exchange monitor for exercise stress testing aboard NASA Space Station

    NASA Technical Reports Server (NTRS)

    Orr, Joseph A.; Westenskow, Dwayne R.; Bauer, Anne

    1989-01-01

    This paper describes an easy-to-use monitor developed to track the weightlessness deconditioning aboard the NASA Space Station, together with the results of testing of a prototype instrument. The monitor measures the O2 uptake and CO2 production, and calculates the maximum O2 uptake and anaerobic threshold during an exercise stress test. The system uses two flowmeters in series to achieve a completely automatic calibration, and uses breath-by-breath compensation for sample line-transport delay. The monitor was evaluated using two laboratory methods and was shown to be accurate. The system's block diagram and the bench test setup diagram are included.

  7. Prevalence of high risk Tl-201 scintigraphic findings in patients with coronary artery disease: Relation to coronary anatomy and ECG stress test findings

    SciTech Connect

    Ryan, J.M.; Nygaard, T.W.; Gibson, R.S.; Gascho, J.A.; Watson, D.D.; Beller, G.A.

    1984-01-01

    The prevalence of a high risk exercise (Ex) Tl-201 (Tl) scintigram (scint) was determined in 295 consecutive patients (pts) with angiographic (angio) (>50% stenosis) coronary artery disease (CAD) and correlated with extent of CAD and Ex stress test findings. A high risk scint by quantitative criteria was defined as either: 1) a typical left main (LM) CAD pattern showing greater than or equal to 25% homogenous disease in Tl activity in septal and posterolateral walls; 2) a multivessel disease (MVD) pattern showing abnormal Tl uptake and/or washout in multiple vascular scan segments; 3) increased lung Tl uptake. The typical LMCAD pattern was observed in 6 of 43 pts (14%) with LMCAD compared to 2% of 53 pts with 3VD (p=0.03), 3% of 99 pts with 2VD (p=0.02) and 2% of 100 pts with 1VD (p-0.01). The MVD scint pattern was seen in 67% of pts with LMCAD compared to 49% (p=0.05) in 3VD pts, 41% (p=0.004) in 2VD pts and 24% (p=<0.0001) in 1VD pts. Prevalence of abnormal lung Tl was comparable in LMCAD (42%), 3VD (38%) and 2VD (34%) pts, but greater than observed in 1VD pts (26%; p=0.05). High risk ECG stress test was defined as 2 or more of: 1) >2.0 mm of ST decreasing; 2) greater than or equal to1.0 mm ST decreasing persisting >5 min post-EX; 3) ST decreasing at less than or equal to5 METS; 4) greater than or equal to10 mm Hg decreasing in Ex blood pressure. A high risk ECG stress test was observed in 58% of LMCAD pts compared to 32% of 3VD pts (p=0.009), 31% of 2VD pts (p=0.003) and 16% of 1VD pts (p<0.0001). Eighty-six % of LMCAD and 70% of 2 and 3VD pts had either a high risk Ex scint or stress test. Thus, EX Tl-201 scint appears useful in identifying high risk CAD pts.

  8. Communication and abnormal behaviour.

    PubMed

    Crown, S

    1979-01-01

    In this paper the similarities between normal and abnormal behaviour are emphasized and selected aspects of communication, normal and aberrant, between persons are explored. Communication in a social system may be verbal or non-verbal: one person's actions cause a response in another person. This response may be cognitive, behavioural or physiological. Communication may be approached through the individual, the social situation or social interaction. Psychoanalysis approaches the individual in terms of the coded communications of psychoneurotic symptoms or psychotic behaviour; the humanist-existential approach is concerned more with emotional expression. Both approaches emphasize the development of individual identity. The interaction between persons and their social background is stressed. Relevant are sociological concepts such as illness behaviour, stigma, labelling, institutionalization and compliance. Two approaches to social interactions are considered: the gamesplaying metaphor, e.g. back pain as a psychosocial manipulation--the 'pain game'; and the 'spiral of reciprocal perspectives' which emphasizes the interactional complexities of social perceptions. Communicatory aspects of psychological treatments are noted: learning a particular metaphor such as 'resolution' of the problem (psychotherapy), learning more 'rewarding' behaviour (learning theory) or learning authenticity or self-actualization (humanist-existential).

  9. Communication and abnormal behaviour.

    PubMed

    Crown, S

    1979-01-01

    In this paper the similarities between normal and abnormal behaviour are emphasized and selected aspects of communication, normal and aberrant, between persons are explored. Communication in a social system may be verbal or non-verbal: one person's actions cause a response in another person. This response may be cognitive, behavioural or physiological. Communication may be approached through the individual, the social situation or social interaction. Psychoanalysis approaches the individual in terms of the coded communications of psychoneurotic symptoms or psychotic behaviour; the humanist-existential approach is concerned more with emotional expression. Both approaches emphasize the development of individual identity. The interaction between persons and their social background is stressed. Relevant are sociological concepts such as illness behaviour, stigma, labelling, institutionalization and compliance. Two approaches to social interactions are considered: the gamesplaying metaphor, e.g. back pain as a psychosocial manipulation--the 'pain game'; and the 'spiral of reciprocal perspectives' which emphasizes the interactional complexities of social perceptions. Communicatory aspects of psychological treatments are noted: learning a particular metaphor such as 'resolution' of the problem (psychotherapy), learning more 'rewarding' behaviour (learning theory) or learning authenticity or self-actualization (humanist-existential). PMID:261653

  10. Do stress hormones connect environmental effects with behavior in the forced swim test?

    PubMed

    Pintér, Ottó; Domokos, Ágnes; Mergl, Zsuzsa; Mikics, Éva; Zelena, Dóra

    2011-01-01

    Forced swim test (FST) is a widely used test for antidepressant development. Depression is a stress related disease, as hormones of the stress-axis can modify mood. However it is not clear, how the appearance of depressive-like behavior (floating) in FST is connected with changes in the stress-hormone levels. We hypothesized, that different manipulations would alter the behavior through changes in stress-hormone levels. First the effect of environmental alterations was studied. Increasing water-temperature enhanced floating time together with a decrease in adrenocorticotropin levels. During the dark phase of the day rats spent more time with floating independently from the actual lighting. Neither the phase nor the actual lighting had significant effect on adrenocorticotropin concentrations with higher corticosterone levels during the dark phase. At greater water depth rats float less but the size of animals had no effect. Water depth did not influence adrenocorticotropin and corticosterone responses, but the size of the rats significantly affected both factors. Secondly, administration of imipramine reduced floating and adrenocorticotropin level without affecting corticosterone. Despite the known connection between depression and stress we did not find a correlation between floating behavior and hormone levels. As an alternative mechanism imipramine-induced heart rate and core body temperature decrease was found by telemetric approach. This study is the first summary in rats examining the effect of wide range of environmental alterations during FST. It seems likely that both brain monoamines and stress-axis take part in the development of depression, but these pathways are regulated independently.

  11. Do stress hormones connect environmental effects with behavior in the forced swim test?

    PubMed

    Pintér, Ottó; Domokos, Ágnes; Mergl, Zsuzsa; Mikics, Éva; Zelena, Dóra

    2011-01-01

    Forced swim test (FST) is a widely used test for antidepressant development. Depression is a stress related disease, as hormones of the stress-axis can modify mood. However it is not clear, how the appearance of depressive-like behavior (floating) in FST is connected with changes in the stress-hormone levels. We hypothesized, that different manipulations would alter the behavior through changes in stress-hormone levels. First the effect of environmental alterations was studied. Increasing water-temperature enhanced floating time together with a decrease in adrenocorticotropin levels. During the dark phase of the day rats spent more time with floating independently from the actual lighting. Neither the phase nor the actual lighting had significant effect on adrenocorticotropin concentrations with higher corticosterone levels during the dark phase. At greater water depth rats float less but the size of animals had no effect. Water depth did not influence adrenocorticotropin and corticosterone responses, but the size of the rats significantly affected both factors. Secondly, administration of imipramine reduced floating and adrenocorticotropin level without affecting corticosterone. Despite the known connection between depression and stress we did not find a correlation between floating behavior and hormone levels. As an alternative mechanism imipramine-induced heart rate and core body temperature decrease was found by telemetric approach. This study is the first summary in rats examining the effect of wide range of environmental alterations during FST. It seems likely that both brain monoamines and stress-axis take part in the development of depression, but these pathways are regulated independently. PMID:21505269

  12. LLNL and TRW extend benchmark environmental stress testing for two alternative printed board cleaners

    SciTech Connect

    Hersey, R.J. Jr.; Meltzer, M.; Hofstad, H.W.; Lawrence, M.; Sanborn, R.; Arauco, H.

    1995-03-01

    TRW Corporation and LLNL jointly conducted a testing program to evaluate the effectiveness of non-CFC defluxing chemistries on printed boards designed for high reliability military and aerospace applications. TRW assessed existing data for alternative chemistries, selected candidates for further testing, implemented the cleaning processes, and performed ionic conductivity testing on the spent solvents. LLNL designed and fabricated special circuit boards with interdigitated comb patterns to allow insulation resistance (IR) measurements under selected soldered components. LLNL designed the test and measurement setup and conducted accelerated environmental stress testing of flux residues for 28 days following cleaning. Statistical analyses of the IR measurements were correlated with visual observations and spectroscopic (FTIR) measurements. Performance of the alternative chemistries was compared with that of a standard CFC cleaning agent also included in the test program. The program was designed to follow the same environmental stress and electrical measurement requirements as the IPC/DOD/EPA Ad Hoc Solvent Working Group`s benchmark 7-day test plan, but with certain minor modifications and extension to 28 days.

  13. Sympathetic neural reactivity to mental stress in humans: test-retest reproducibility.

    PubMed

    Fonkoue, Ida T; Carter, Jason R

    2015-12-01

    Mental stress consistently increases arterial blood pressure, but this reliable pressor response is often associated with highly variable muscle sympathetic nerve activity (MSNA) responsiveness between individuals. Although MSNA has been shown to be reproducible within individuals at rest and during the cold pressor test (CPT), intraindividual reproducibility of MSNA responsiveness to mental stress has not been adequately explored. The purpose of this study was to examine MSNA reactivity to mental stress across three experimental sessions. Sixteen men and women (age 21 ± 1 yr) performed two experimental sessions within a single laboratory visit and a third experimental session 1 mo later. Each experimental session consisted of a mental stress trial via mental arithmetic and a CPT trial. Blood pressure, heart rate (HR), and MSNA were measured, and the consistencies of these variables were determined using intraclass correlation (Cronbach's α coefficient). MSNA, mean arterial pressure (MAP), and HR were highly reproducible across the baselines preceding mental stress (Cronbach's α ≥ 0.816, P ≤ 0.001) and CPT (Cronbach's α ≥ 0.782, P ≤ 0.001). Across the three mental stress trials, changes in MSNA (Cronbach's α = 0.875; P = 0.001), MAP (Cronbach's α = 0.749; P < 0.001), and HR (Cronbach's α = 0.919; P < 0.001) were reproducible. During CPT, changes in MSNA (Cronbach's α = 0.805; P = 0.008), MAP (Cronbach's α = 0.878; P < 0.001), and HR (Cronbach's α = 0.927; P < 0.001) remained consistent across the three sessions. In conclusion, our findings demonstrate that MSNA reactivity to mental stress is consistent within a single laboratory visit and across laboratory sessions conducted on separate days. PMID:26400186

  14. 12 CFR Appendix A to Part 252 - Policy Statement on the Scenario Design Framework for Stress Testing

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Protection Act (Dodd-Frank Act or Act) and through its capital plan rule (12 CFR 225.8). Under the stress... supervisory and company-run stress tests (macroeconomic scenarios).23 21 12 U.S.C. 5365(i)(1); 12 CFR part 252, subpart F. 22 12 U.S.C. 5365(i)(2); 12 CFR part 252, subparts G and H. 23 The stress test rules...

  15. Reproduction and modulation of the stress response: an experimental test in the house sparrow

    PubMed Central

    Lendvai, Ádám Zoltán; Giraudeau, Mathieu; Chastel, Olivier

    2006-01-01

    The stress response is highly variable among individuals, but the causes of this variation remain largely unknown. In response to stressors, vertebrates secrete elevated levels of glucocorticoids which enhance survival, but concurrently interfere with reproduction. We tested the hypothesis that individuals flexibly modulate their stress response with respect to the reproductive value of their brood in free-living house sparrows (Passer domesticus). We experimentally increased or decreased clutch size during the nestling period and found that parents tending enlarged clutches responded less strongly to a stressor than those tending reduced clutches. In addition, we examined whether individuals responded less strongly to a stressor as the breeding season progressed and future reproductive opportunities declined. We found that the stress response decreased with breeding date during the birds' first breeding attempt, but it remained constant during their second breeding attempt. Within-individual variability in the stress response was related to the brood size manipulations the birds received in their two consecutive breeding attempts. These results provide the first experimental support for the hypothesis that individuals actively modulate their stress response with respect to the value of current reproduction. PMID:17164203

  16. Insights Gained from Ultrasonic Testing of Piping Welds Subjected to the Mechanical Stress Improvement Process

    SciTech Connect

    Anderson, Michael T.; Cinson, Anthony D.; Crawford, Susan L.; Diaz, Aaron A.; Moran, Traci L.

    2010-12-01

    Pacific Northwest National Laboratory (PNNL) is assisting the United States Nuclear Regulatory Commission (NRC) in developing a position on the management of primary water stress corrosion cracking (PWSCC) in leak-before-break piping systems. Part of this involves determining whether inspections alone, or inspections plus mitigation, are needed. This work addresses the reliability of ultrasonic testing (UT) of cracks that have been mitigated by the mechanical stress improvement process (MSIP). The MSIP has been approved by the NRC (NUREG-0313) since 1986 and modifies residual stresses remaining after welding with compressive, or neutral, stresses near the inner diameter surface of the pipe. This compressive stress is thought to arrest existing cracks and inhibit new crack formation. To evaluate the effectiveness of the MSIP and the reliability of ultrasonic inspections, flaws were evaluated both before and after MSIP application. An initial investigation was based on data acquired from cracked areas in 325-mm-diameter piping at the Ignalina Nuclear Power Plant (INPP) in Lithuania. In a follow-on exercise, PNNL acquired and evaluated similar UT data from a dissimilar metal weld (DMW) specimen containing implanted thermal fatigue cracks. The DMW specimen is a carbon steel nozzle-to-safe end-to-stainless steel pipe section that simulates a pressurizer surge nozzle. The flaws were implanted in the nozzle-to-safe end Alloy 82/182 butter region. Results are presented on the effects of MSIP on specimen surfaces, and on UT flaw responses.

  17. Enhanced stress response by a bilateral feet compared to a unilateral hand Cold Pressor Test.

    PubMed

    Larra, Mauro F; Schilling, Thomas M; Röhrig, Philipp; Schächinger, Hartmut

    2015-01-01

    The Cold Pressor Test (CPT) is a frequently employed laboratory stress protocol. However, with many experimental designs the application in its classic form (immersion of the dominant hand into ice-water) is problematic as unilateral stimulation may need to be avoided and/or hands are required for further measurements. Here, we describe a simple modification of the classic CPT in which both feet are immersed into ice-water and compare the evoked neuroendocrine stress response to the classic CPT in a within-subjects design. Twenty-four healthy participants were exposed to each of both CPT versions on two subsequent days in randomized order. Heart rate, blood pressure, salivary alpha-amylase and cortisol were measured at baseline and during or after CPT exposition, respectively, along with subjective ratings of pain and stress. The bilateral feet CPT induced marked increases in all measured stress parameters. Moreover, with the exception of blood pressure, autonomic and endocrine responses were enhanced compared to the classic CPT. The bilateral feet CPT thus is a valid and simple modification and may be useful when the application of the classic CPT is unfeasible or a stronger neuroendocrine stress response is of interest. PMID:26123388

  18. Enhanced stress response by a bilateral feet compared to a unilateral hand Cold Pressor Test.

    PubMed

    Larra, Mauro F; Schilling, Thomas M; Röhrig, Philipp; Schächinger, Hartmut

    2015-01-01

    The Cold Pressor Test (CPT) is a frequently employed laboratory stress protocol. However, with many experimental designs the application in its classic form (immersion of the dominant hand into ice-water) is problematic as unilateral stimulation may need to be avoided and/or hands are required for further measurements. Here, we describe a simple modification of the classic CPT in which both feet are immersed into ice-water and compare the evoked neuroendocrine stress response to the classic CPT in a within-subjects design. Twenty-four healthy participants were exposed to each of both CPT versions on two subsequent days in randomized order. Heart rate, blood pressure, salivary alpha-amylase and cortisol were measured at baseline and during or after CPT exposition, respectively, along with subjective ratings of pain and stress. The bilateral feet CPT induced marked increases in all measured stress parameters. Moreover, with the exception of blood pressure, autonomic and endocrine responses were enhanced compared to the classic CPT. The bilateral feet CPT thus is a valid and simple modification and may be useful when the application of the classic CPT is unfeasible or a stronger neuroendocrine stress response is of interest.

  19. Default Mode Network in Concussed Individuals in Response to the YMCA Physical Stress Test

    PubMed Central

    Zhang, Kai; Johnson, Brian; Gay, Michael; Horovitz, Silvina G.; Hallett, Mark; Sebastianelli, Wayne

    2012-01-01

    Abstract We hypothesize that the evolution of mild traumatic brain injury (mTBI) may be related to differential effects of a concussive blow on the functional integrity of the brain default mode network (DMN) at rest and/or in response to physical stress. Accordingly, in this resting-state functional magnetic resonance imaging (fMRI) study, we examined 14 subjects 10±2 days post-sports-related mTBI and 15 age-matched normal volunteers (NVs) to investigate the possibility that the integrity of the DMN is disrupted at the resting state and/or following the physical stress test. First, all mTBI subjects were asymptomatic based upon clinical evaluation and neuropsychological (NP) assessments prior to the MRI session. Second, the functional integrity within the DMN, a main resting-state network, remained resilient to a single concussive blow. Specifically, the major regions of interest (ROIs) constituting the DMN (e.g., the posterior cingulate cortex [PCC]/precuneus area, the medial prefrontal cortex [MPFC], and left and right lateral parietal cortices [LLP and RLP]) and the connectivity within these four ROIs was similar between NVs and mTBI subjects prior to the YMCA physical stress test. However, the YMCA physical stress test disrupted the DMN, significantly reducing the magnitude of the connection between the PCC and left lateral parietal ROI, and PCC and right lateral parietal ROI, as well as between the PCC and MPFC in mTBI subjects. Thus while the DMN remained resilient to a single mTBI without exertion at 10 days post-injury, it was altered in response to limited physical stress. This may explain some clinical features of mTBI and provide some insight into its mechanism. This important finding should be considered by clinical practitioners when making decisions regarding return-to-play and clearing mTBI athletes for sports participation. PMID:22040294

  20. 78 FR 72534 - Policy Statement on the Principles for Development and Distribution of Annual Stress Test Scenarios

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-03

    ... annual stress test cycle set out in Table 1. \\1\\ Public Law 111-203, 124 Stat. 1376 (2010). \\2\\ 77 FR... development and distribution of future stress test scenarios. \\4\\ 77 FR 69553 (Nov. 20, 2012). B. Summary of... will apply to develop and distribute those scenarios for covered banks. \\1\\ 77 FR 62417 (Oct. 15,...

  1. 78 FR 78165 - Orders: Reporting by Regulated Entities of Stress Testing Results as of September 30, 2013...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-26

    ... September 26, 2013, at 78 FR 59219. FHFA also is amending the Summary Instructions and Guidance, which... AGENCY 12 CFR Part 1238 Orders: Reporting by Regulated Entities of Stress Testing Results as of September... prescribe for the regulated entities the scenarios to be used for stress testing. The Summary...

  2. On the correct interpretation of measured force and calculation of material stress in biaxial tests.

    PubMed

    Nolan, D R; McGarry, J P

    2016-01-01

    Biaxial tests are commonly used to investigate the mechanical behaviour of soft biological tissues and polymers. In the current paper we uncover a fundamental problem associated with the calculation of material stress from measured force in standard biaxial tests. In addition to measured forces, localised unmeasured shear forces also occur at the clamps and the inability to quantify such forces has significant implications for the calculation of material stress from simplified force-equilibrium relationships. Unmeasured shear forces are shown to arise due to two distinct competing contributions: (1) negative shear force due to stretching of the orthogonal clamp, and (2) positive shear force as a result of material Poisson-effect. The clamp shear force is highly dependent on the specimen geometry and the clamp displacement ratio, as consequently, is the measured force-stress relationship. Additionally in this study we demonstrate that commonly accepted formulae for the estimation of material stress in the central region of a cruciform specimen are highly inaccurate. A reliable empirical correction factor for the general case of isotropic materials must be a function of specimen geometry and the biaxial clamp displacement ratio. Finally we demonstrate that a correction factor for the general case of non-linear anisotropic materials is not feasible and we suggest the use of inverse finite element analysis as a practical means of interpreting experimental data for such complex materials. PMID:26327453

  3. On the correct interpretation of measured force and calculation of material stress in biaxial tests.

    PubMed

    Nolan, D R; McGarry, J P

    2016-01-01

    Biaxial tests are commonly used to investigate the mechanical behaviour of soft biological tissues and polymers. In the current paper we uncover a fundamental problem associated with the calculation of material stress from measured force in standard biaxial tests. In addition to measured forces, localised unmeasured shear forces also occur at the clamps and the inability to quantify such forces has significant implications for the calculation of material stress from simplified force-equilibrium relationships. Unmeasured shear forces are shown to arise due to two distinct competing contributions: (1) negative shear force due to stretching of the orthogonal clamp, and (2) positive shear force as a result of material Poisson-effect. The clamp shear force is highly dependent on the specimen geometry and the clamp displacement ratio, as consequently, is the measured force-stress relationship. Additionally in this study we demonstrate that commonly accepted formulae for the estimation of material stress in the central region of a cruciform specimen are highly inaccurate. A reliable empirical correction factor for the general case of isotropic materials must be a function of specimen geometry and the biaxial clamp displacement ratio. Finally we demonstrate that a correction factor for the general case of non-linear anisotropic materials is not feasible and we suggest the use of inverse finite element analysis as a practical means of interpreting experimental data for such complex materials.

  4. Early-stage visual processing abnormalities in high-functioning autism spectrum disorder (ASD).

    PubMed

    Baruth, Joshua M; Casanova, Manuel F; Sears, Lonnie; Sokhadze, Estate

    2010-06-01

    It has been reported that individuals with autism spectrum disorder (ASD) have abnormal responses to the sensory environment. For these individuals sensory overload can impair functioning, raise physiological stress, and adversely affect social interaction. Early-stage (i.e. within 200ms of stimulus onset) auditory processing abnormalities have been widely examined in ASD using event-related potentials (ERP), while ERP studies investigating early-stage visual processing in ASD are less frequent. We wanted to test the hypothesis of early-stage visual processing abnormalities in ASD by investigating ERPs elicited in a visual oddball task using illusory figures. Our results indicate that individuals with ASD have abnormally large cortical responses to task irrelevant stimuli over both parieto-occipital and frontal regions-of-interest (ROI) during early stages of visual processing compared to the control group. Furthermore, ASD patients showed signs of an overall disruption in stimulus discrimination, and had a significantly higher rate of motor response errors.

  5. Field stress corrosion tests in brine environments of the Salton Sea known geothermal resource area

    SciTech Connect

    Carter, J.P.; Cramer, S.D.

    1980-01-01

    Corrosion research is being conducted to determine suitable construction materials for geothermal resource recovery plants. As part of this research, a 30-day stress corrosion test was conducted at the Salton Sea Known Geothermal Resource Area on seven iron- and nickel-base alloys in four brine and steam process streams using wellhead brine from geothermal well Magmamax 1. The tests showed transgranular cracking of AISI 316L stainless steel and intergranular and transgranular cracking of AISI 430 stainless steel in all four process streams. E-Brite 26-1 exhibited intergranular and transgranular cracking in three of the four process streams. Carbon steel, Inconel 625 and Hastelloys G and C-276 show no evidence of stress corrosion cracking.

  6. Imipramine and alprazolam effects on stress test reactivity in panic disorder.

    PubMed

    Roth, W T; Margraf, J; Ehlers, A; Haddad, J M; Maddock, R J; Agras, W S; Taylor, C B

    1992-01-01

    The reactivity of 40 panic disorder patients on mental arithmetic, cold pressor, and 5% CO2 inhalation stressors was tested before and after 8 weeks of treatment with imipramine, alprazolam, or placebo. Mean levels of subjective and physiological stress measures were compared during a baseline before any stressors were given, and at anticipation, stressor, and recovery periods for each stressor. After treatment, imipramine patients differed from the other two treatment groups on the prestressor baseline in showing higher systolic blood pressure (mean difference about 10 mmHg), higher diastolic blood pressure (10 mm Hg), higher heart rate (15 bpm), less respiratory sinus arrhythmia, shorter pulse transit time, and lower T-wave amplitude. Respiratory measures, electrodermal measures, body movement, and self-reported anxiety and excitement did not distinguish the groups. Reactivity to the stress tests was unaffected by the medications, but tonic differences present in the baseline persisted.

  7. In vitro blood flow model with physiological wall shear stress for hemocompatibility testing-An example of coronary stent testing.

    PubMed

    Engels, Gerwin Erik; Blok, Sjoerd Leendert Johannes; van Oeveren, Willem

    2016-01-01

    Hemocompatibility of blood contacting medical devices has to be evaluated before their intended application. To assess hemocompatibility, blood flow models are often used and can either consist of in vivo animal models or in vitro blood flow models. Given the disadvantages of animal models, in vitro blood flow models are an attractive alternative. The in vitro blood flow models available nowadays mostly focus on generating continuous flow instead of generating a pulsatile flow with certain wall shear stress, which has shown to be more relevant in maintaining hemostasis. To address this issue, the authors introduce a blood flow model that is able to generate a pulsatile flow and wall shear stress resembling the physiological situation, which the authors have coined the "Haemobile." The authors have validated the model by performing Doppler flow measurements to calculate velocity profiles and (wall) shear stress profiles. As an example, the authors evaluated the thrombogenicity of two drug eluting stents, one that was already on the market and one that was still under development. After identifying proper conditions resembling the wall shear stress in coronary arteries, the authors compared the stents with each other and often used reference materials. These experiments resulted in high contrast between hemocompatible and incompatible materials, showing the exceptional testing capabilities of the Haemobile. In conclusion, the authors have developed an in vitro blood flow model which is capable of mimicking physiological conditions of blood flow as close as possible. The model is convenient in use and is able to clearly discriminate between hemocompatible and incompatible materials, making it suitable for evaluating the hemocompatible properties of medical devices. PMID:27435456

  8. Prognostic value of non-invasive stress testing for coronary artery disease in obese patients.

    PubMed

    Bigvava, Tamar; Zamani, Seyedeh Mahsa; Pieske-Kraigher, Elisabeth; Gebker, Rolf; Pieske, Burkert; Kelle, Sebastian

    2015-12-01

    Detecting coronary artery disease (CAD) in obese patients remains a challenge but can have substantial prognostic implications for this patient group. Until now, sufficient data was not available on which to base the selection of the imaging modality in obese patients. The decision on which imaging modality to use should therefore follow the general guidelines. In this article, the authors discuss the prognostic value of the different non-invasive stress testing methods for CAD in obese patients.

  9. Repeatable electrical measurement instrumentation for use in the accelerated stress testing of thin film solar cells

    NASA Technical Reports Server (NTRS)

    Davis, C. W.; Lathrop, J. W.

    1985-01-01

    Attention is given to the construction, calibration, and performance of a repeatable measurement system for use in conjunction with the accelerated stress testing of a-Si:H cells. A filtered diode array is utilized to approximate the spectral response of any type of solar cell in discrete portions of the spectrum. It is noted that in order to achieve the necessary degree of overall repeatability, it is necessary to pay particular attention to methods of contacting and positioning the cells.

  10. The use of rapid prototyped implants to simulate knee joint abnormalities for in vitro testing: a validation study with replica implants of the native trochlea.

    PubMed

    Van Haver, Annemieke; De Roo, Karel; De Beule, Matthieu; Van Cauter, Sofie; Labey, Luc; De Baets, Patrick; Claessens, Tom; Verdonk, Peter

    2014-08-01

    To investigate the biomechanical effect of skeletal knee joint abnormalities, the authors propose to implant pathologically shaped rapid prototyped implants in cadaver knee specimens. This new method was validated by replacing the native trochlea by a replica implant on four cadaver knees with the aid of cadaver-specific guiding instruments. The accuracy of the guiding instruments was assessed by measuring the rotational errors of the cutting planes (on average 3.01° in extension and 1.18° in external/internal rotation). During a squat and open chain simulation, the patella showed small differences in its articulation with the native trochlea and the replica trochlea, which could partially be explained by the rotational errors of the implants. This study concludes that this method is valid to investigate the effect of knee joint abnormalities with a replica implant as a control condition to account for the influence of material properties and rotational errors of the implant.

  11. Simulated Service and Stress Corrosion Cracking Testing for Friction Stir Welded Spun Form Domes

    NASA Technical Reports Server (NTRS)

    Stewart, Thomas J.; Torres, Pablo D.; Caratus, Andrei A.; Curreri, Peter A.

    2010-01-01

    Damage tolerance testing development was required to help qualify a new spin forming dome fabrication process for the Ares 1 program at Marshall Space Flight Center (MSFC). One challenge of the testing was due to the compound curvature of the dome. The testing was developed on a sub-scale dome with a diameter of approximately 40 inches. The simulated service testing performed was based on the EQTP1102 Rev L 2195 Aluminum Lot Acceptance Simulated Service Test and Analysis Procedure generated by Lockheed Martin for the Space Shuttle External Fuel Tank. This testing is performed on a specimen with an induced flaw of elliptical shape generated by Electrical Discharge Machining (EDM) and subsequent fatigue cycling for crack propagation to a predetermined length and depth. The specimen is then loaded in tension at a constant rate of displacement at room temperature until fracture occurs while recording load and strain. An identical specimen with a similar flaw is then proof tested at room temperature to imminent failure based on the critical offset strain achieved by the previous fracture test. If the specimen survives the proof, it is then subjected to cryogenic cycling with loads that are a percentage of the proof load performed at room temperature. If all cryogenic cycles are successful, the specimen is loaded in tension to failure at the end of the test. This standard was generated for flat plate, so a method of translating this to a specimen of compound curvature was required. This was accomplished by fabricating a fixture that maintained the curvature of the specimen rigidly with the exception of approximately one-half inch in the center of the specimen containing the induced flaw. This in conjunction with placing the center of the specimen in the center of the load train allowed for successful testing with a minimal amount of bending introduced into the system. Stress corrosion cracking (SCC) tests were performed using the typical double beam assembly and with 4

  12. Test Results of a Nb3Sn Wind/React"Stress-Managed" Block Dipole

    SciTech Connect

    McInturff, A.; Blackburn, R.; Diaczenko, N.; Elliott, T.; Henchel, W.; Jaisle, A.; McIntyre, P.; Noyes, P.; Sattarov, A.; Lietzke, A.; Hafalia Jr., R.; Lau, W.; Nyman, M.; Bish, P.

    2007-06-01

    A second phase of a high field dipole technology development has been tested. A Nb{sub 3}Sn block-coil model dipole was fabricated, using magnetic mirror geometry and wind/react coil technology. The primary objective of this phase was to make a first experimental test of the stress-management strategy pioneered at Texas A&M. In this strategy a high-strength support matrix is integrated with the windings to intercept Lorentz stress from the inner winding so that it does not accumulate in the outer winding. The magnet attained a field that was consistent with short sample limit on the first quench; there was no training. The decoupling of Lorentz stress between inner and outer windings was validated. In ramp rate studies the magnet exhibited a remarkable robustness in rapid ramping operation. It reached 85% of short sample(ss) current even while ramping 2-3 T/s. This robustness is attributed to the orientation of the Rutherford cables parallel to the field in the windings, instead of the transverse orientation that characterizes common dipole designs. Test results are presented and the next development phase plans are discussed.

  13. Crack initiation testing of thimble tube material under PWR conditions to determine a stress threshold for IASCC

    NASA Astrophysics Data System (ADS)

    Bosch, R. W.; Vankeerberghen, M.; Gérard, R.; Somville, F.

    2015-06-01

    IASCC (Irradiation Assisted Stress Corrosion Cracking) crack initiation tests have been carried out on thimble tube material retrieved from a Belgian PWR. The crack initiation tests were carried out by constant load testing of thimble tube specimens at different stress levels. The time-to-failure was determined as a function of the applied stress to find a stress threshold under which no stress corrosion cracking will take place. The thimble tube was made of 316L cold-worked stainless steel and the dose profile along the thimble tube ranges from 45 to 80 dpa. This allows adding crack initiation data for dose values that have not been significantly reported, i.e. in the range of 45-55 dpa and at 80 dpa. The results can be used to determine whether the stress under which no IASCC occurs saturates for a dose larger than 30 dpa or whether a small further threshold decrease with dose can be observed. Over a period of four years, more than 40 specimens have been tested with doses ranging from 45 to 80 dpa at stress levels between 40% and 70% of the irradiated yield stress. Fracture occurred at all stress levels (but not all specimens) although the time-to-failure increased with decreasing stress. The results show that intergranular cracking was the main fracture mode in all failed O-rings. Three of six 80 dpa O-rings subjected to 40% and 45% of the yield stress did not fail after six months of testing. Based on these results and a comparison with literature data, an apparent stress limit for IASCC could be estimated at 40% of the irradiated yield stress.

  14. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

  15. Assessment of Initial Test Conditions for Experiments to Assess Irradiation Assisted Stress Corrosion Cracking Mechanisms

    SciTech Connect

    Busby, Jeremy T; Gussev, Maxim N

    2011-04-01

    Irradiation-assisted stress corrosion cracking is a key materials degradation issue in today s nuclear power reactor fleet and affects critical structural components within the reactor core. The effects of increased exposure to irradiation, stress, and/or coolant can substantially increase susceptibility to stress-corrosion cracking of austenitic steels in high-temperature water environments. . Despite 30 years of experience, the underlying mechanisms of IASCC are unknown. Extended service conditions will increase the exposure to irradiation, stress, and corrosive environment for all core internal components. The objective of this effort within the Light Water Reactor Sustainability program is to evaluate the response and mechanisms of IASCC in austenitic stainless steels with single variable experiments. A series of high-value irradiated specimens has been acquired from the past international research programs, providing a valuable opportunity to examine the mechanisms of IASCC. This batch of irradiated specimens has been received and inventoried. In addition, visual examination and sample cleaning has been completed. Microhardness testing has been performed on these specimens. All samples show evidence of hardening, as expected, although the degree of hardening has saturated and no trend with dose is observed. Further, the change in hardening can be converted to changes in mechanical properties. The calculated yield stress is consistent with previous data from light water reactor conditions. In addition, some evidence of changes in deformation mode was identified via examination of the microhardness indents. This analysis may provide further insights into the deformation mode under larger scale tests. Finally, swelling analysis was performed using immersion density methods. Most alloys showed some evidence of swelling, consistent with the expected trends for this class of alloy. The Hf-doped alloy showed densification rather than swelling. This observation may be

  16. Proposed Testing to Assess the Accuracy of Glass-To-Metal Seal Stress Analyses.

    SciTech Connect

    Chambers, Robert S.; Emery, John M; Tandon, Rajan; Antoun, Bonnie R.; Stavig, Mark E.; Newton, Clay S.; Gibson, Cory S; Bencoe, Denise N.

    2014-09-01

    The material characterization tests conducted on 304L VAR stainless steel and Schott 8061 glass have provided higher fidelity data for calibration of material models used in Glass - T o - Metal (GTM) seal analyses. Specifically, a Thermo - Multi - Linear Elastic Plastic ( thermo - MLEP) material model has be en defined for S S304L and the Simplified Potential Energy Clock nonlinear visc oelastic model has been calibrated for the S8061 glass. To assess the accuracy of finite element stress analyses of GTM seals, a suite of tests are proposed to provide data for comparison to mo del predictions.

  17. High Power RF Tests on WR650 Pre-Stressed Planar Windows

    SciTech Connect

    Stirbet, Mircea; Davis, G. Kirk; Elliott, Thomas S.; King, Larry; Powers, Thomas J.; Rimmer, Robert A.; Walker, Richard L.

    2009-11-01

    A new planar, ceramic window intended to be used with WR650 waveguide fundamental power couplers at 1300 MHz or 1500 MHz has been developed. It is based on the pre-stressed planar window concept tested in PEP II and LEDA. A test stand that made use of the 100kW CW 1500 MHz RF system in the JLAB FEL was commissioned and used to apply up to 80 kW traveling wave (TW)to the windows. Two different types of RF windows (brazed and diffusion bonded ceramics) with design specification of 50 kW CW in TW mode were successfully tested both as a gas barrier (intended to operate up to 2 psi) and as a vacuum barrier. The vacuum windows were able to maintain UHV quality vacuum and were successfully operated in the 10{sup -9} mbar range. An overview of the pre-stressed power windows, RF test stand, procedures and RF power testing results will be presented.

  18. Crack initiation observation and local stress analysis in shear fracture tests of ultra-high strength steels

    NASA Astrophysics Data System (ADS)

    Ma, Ninshu; Takada, Kenji; Sugimoto, Nao

    2016-08-01

    To investigate the local strain and stress at the crack initiation position in shear fracture test pieces of ultra-high strength steels, a butterfly shear fracture specimen was employed. The crack initiation position and propagation direction were observed during shear fracture tests by high speed cameras and investigated through analysing the fracture surface by scanning electron microscope. Further, the finite element method was employed and the stress-triaxiality at the crack initiation position was investigated. It can be obtained that the crack initiated at the position where the stress state is close to uniaxial tensile state or plane strain state more than pure shear stress state.

  19. Stress and stress relaxation behaviors of multi-layered polarizer structures under a reliability test condition characterized by use of a bending beam technique

    NASA Astrophysics Data System (ADS)

    Lin, Taiy-In; Hsieh, Chih-Yung; Li, I.-Yin; Leu, Jihperng

    2015-04-01

    The bending curvature, stresses, and stress relaxation of various multi-layered structures with different adhesive layers pertaining to the polarizer in a thin-film transistor liquid-crystal display (TFT-LCD) have been successfully characterized by using bending beam technique under reliability test. To be more specific, three different types of pressure-sensitive adhesive (hard-, middle-, and soft-type) and various poly(vinyl alcohol) (PVA) stretched directions are devised to examine to key stress contributors and correlations with light leakage. The shrinkage stress in stretched PVA film and stress relaxation ability of pressure-sensitive adhesives (PSA) layers are found to be the key factors determining the stress distribution and out-of-plane displacement of a polarizer stack. For hard-type PSA, its polarizer stack generates the highest bending curvature with maximum out-of-plane displacement but minimum in-plane displacement, leading to anisotropic stress distribution with high stress around the edges. On the other hand, polarizer stack with soft-type PSA yields the maximum in-plane displacement but the minimum out-of-plane displacement, resulting in isotropic stress distribution.

  20. Critical assessment of precracked specimen configuration and experimental test variables for stress corrosion testing of 7075-T6 aluminum alloy plate

    NASA Technical Reports Server (NTRS)

    Domack, M. S.

    1985-01-01

    A research program was conducted to critically assess the effects of precracked specimen configuration, stress intensity solutions, compliance relationships and other experimental test variables for stress corrosion testing of 7075-T6 aluminum alloy plate. Modified compact and double beam wedge-loaded specimens were tested and analyzed to determine the threshold stress intensity factor and stress corrosion crack growth rate. Stress intensity solutions and experimentally determined compliance relationships were developed and compared with other solutions available in the literature. Crack growth data suggests that more effective crack length measurement techniques are necessary to better characterize stress corrosion crack growth. Final load determined by specimen reloading and by compliance did not correlate well, and was considered a major source of interlaboratory variability. Test duration must be determined systematically, accounting for crack length measurement resolution, time for crack arrest, and experimental interferences. This work was conducted as part of a round robin program sponsored by ASTM committees G1.06 and E24.04 to develop a standard test method for stress corrosion testing using precracked specimens.

  1. Stress

    MedlinePlus

    ... hurt or killed. Examples include a major accident, war, assault, or a natural disaster. This type of ... stress, so you can avoid more serious health effects. NIH: National Institute of Mental Health

  2. Design and Experimental Evaluation of a 3rd Generation Addressable CMOS Piezoresistive Stress Sensing Test Chip

    SciTech Connect

    Sweet, J.N.; Peterson, D.W.; Hsia, A.H.

    1999-04-13

    Piezoresistive stress sensing chips have been used extensively for measurement of assembly related die surface stresses. Although many experiments can be performed with resistive structures which are directly bonded, for extensive stress mapping it is necessary to have a large number of sensor cells which can be addressed using CMOS logic circuitry. Our previous test chip, the ATC04, has 100 cells, each approximately 0.012 in. on a side, on a chip with a side dimension of 0.45 in. When a cell resistor is addressed, it is connected to a four terminal measurement bus through CMOS transmission gates. In theory, the gate resistances do not affect the measurement. In practice, there may be subtle effects which appear when very high accuracy is required. At high temperatures, gate leakage can increase to a point at which the resistor measurement becomes inaccurate. For ATC04 this occurred at or above 50 C. Here, we report on the first measurements obtained with a new prototype test chip, the ATC06. This prototype was fabricated in a 0.5 micron feature size silicided CMOS process using the MOSIS prototyping facility. The cell size was approximately 0.004 in. on a side. In order to achieve piezoresistive behavior for the implanted resistors it was necessary to employ a non-standard silicide ''blocking'' process. The stress sensitivity of both implanted and polysilicon blocked resistors is discussed. Using a new design strategy for the CMOS logic, it was possible to achieve a design in which only 5 signals had to be routed to a cell for addressing vs. 9 for ATC04. With our new design, the resistor under test is more effectively electrically isolated from other resistors on the chip, thereby improving high temperature performance. We present data showing operation up to 140 C.

  3. Antidepressant-like effects of Sanyuansan in the mouse forced swim test, tail suspension test, and chronic mild stress model.

    PubMed

    Yan, Shuo; You, Zi-Li; Zhao, Qiu-Ying; Peng, Cheng; He, Gang; Gou, Xiao-Jun; Lin, Bin

    2015-12-01

    Natural products have been widely reported as effective therapeutic alternatives for treatment of depression. Sanyuansan is a compound recipe composed of ginseng total saponins, fish oil, and valeriana. The aims of this study were to validate whether Sanyuansan has antidepressant-like effects through acute behavioral tests including the forced swimming test (FST), tail suspension test (TST), locomotor activity test, and chronic mild stress (CMS) mice model of depression. C57BL/6 mice were given oral administration of 30 mg/kg imipramine, Sanyuansan, and saline, respectively. The acute behavioral tests including the TST, FST, and locomotor activity test were done after the administration of drugs for consecutively three times (24 hours, 1 hour, and 0.5 hour prior to the tests). Furthermore, the sucrose preference and the serum corticosterone level of mice in the CMS model were examined. Sanyuansan only at 900 mg/kg markedly reduced immobility time in the TST compared with the saline-treated group of mice. Sanyuansan at doses of 225 mg/kg, 450 mg/kg, and 900 mg/kg significantly reduced immobility time of mice in the FST. Sanyuansan reversed the CMS-induced anhedonia and hyperactivation of the hypothalamus-pituitary-adrenal axis. In addition, our results showed that neither imipramine nor Sanyuansan at any dosage increased spontaneous motor activity. These results suggested that Sanyuansan induced significant antidepressant-like effects in mice in both acute and chronic animal models, which seemed unlikely to be attributed to an increase in locomotor activities of mice, and had no sedative-like effects. PMID:26709221

  4. Antidepressant-like effects of Sanyuansan in the mouse forced swim test, tail suspension test, and chronic mild stress model.

    PubMed

    Yan, Shuo; You, Zi-Li; Zhao, Qiu-Ying; Peng, Cheng; He, Gang; Gou, Xiao-Jun; Lin, Bin

    2015-12-01

    Natural products have been widely reported as effective therapeutic alternatives for treatment of depression. Sanyuansan is a compound recipe composed of ginseng total saponins, fish oil, and valeriana. The aims of this study were to validate whether Sanyuansan has antidepressant-like effects through acute behavioral tests including the forced swimming test (FST), tail suspension test (TST), locomotor activity test, and chronic mild stress (CMS) mice model of depression. C57BL/6 mice were given oral administration of 30 mg/kg imipramine, Sanyuansan, and saline, respectively. The acute behavioral tests including the TST, FST, and locomotor activity test were done after the administration of drugs for consecutively three times (24 hours, 1 hour, and 0.5 hour prior to the tests). Furthermore, the sucrose preference and the serum corticosterone level of mice in the CMS model were examined. Sanyuansan only at 900 mg/kg markedly reduced immobility time in the TST compared with the saline-treated group of mice. Sanyuansan at doses of 225 mg/kg, 450 mg/kg, and 900 mg/kg significantly reduced immobility time of mice in the FST. Sanyuansan reversed the CMS-induced anhedonia and hyperactivation of the hypothalamus-pituitary-adrenal axis. In addition, our results showed that neither imipramine nor Sanyuansan at any dosage increased spontaneous motor activity. These results suggested that Sanyuansan induced significant antidepressant-like effects in mice in both acute and chronic animal models, which seemed unlikely to be attributed to an increase in locomotor activities of mice, and had no sedative-like effects.

  5. Effect of thioperamide on modified forced swimming test-induced oxidative stress in mice.

    PubMed

    Akhtar, Mohd; Pillai, K K; Vohora, Divya

    2005-10-01

    This study was designed i) to investigate the role of histamine H3-receptor ligands on mouse modified forced swimming test, a method that distinguishes the catecholaminergic behaviour with that of serotonergic compounds and ii) to evaluate the role of free radicals in mediation of such effects. Swiss strain albino mice were treated with different doses of histamine H3-receptor antagonist thioperamide (3.75, 7.5 and 15 mg/kg intraperitoneally) and agonist (R)-alpha-methylhistamine (5 microg intracerebroventricularly). The climbing, swimming and immobility times were recorded for 6 min. Immediately after modified forced swimming test, the animals were sacrificed and parameters of oxidative stress were assessed in the brain by measuring the thiobarbituric acid reactive substance (TBARS), glutathione (GSH) and catalase levels. Thioperamide (7.5 and 15 mg/kg intraperitoneally) dose-dependently decreased immobility time and increased swimming time but not climbing time. The behaviour of mice treated with (R)-alpha-methylhistamine was similar to that of control mice. A significant reduction in GSH and an increase in catalase levels were observed in brains of mice exposed to modified forced swimming test. Thioperamide pretreatment dose-dependently reversed such an alteration in oxidative stress parameters. (R)-alpha-methylhistamine caused a reversal of altered catalase but not GSH levels. Thioperamide shows antidepressant effects in the modified forced swimming test and causes a reversal of the test-induced oxidative stress indicating its antioxidant potential. The antidepressant effect of thioperamide appears to be mediated via serotonergic and/or antioxidant mechanisms.

  6. Construction and component testing of TAMU3, a 14 Tesla stress-managed Nb3Sn model dipole

    NASA Astrophysics Data System (ADS)

    Holik, Eddie Frank, III; Benson, Chris; Blackburn, Raymond; Diaczenko, Nick; Elliott, Timothy; Jaisle, Andrew; McInturff, A.; McIntyre, P.; Sattarov, Akhdiyor

    2012-06-01

    We report the construction and testing of components of TAMU3, a 14 Tesla Nb3Sn block-coil dipole. A primary goal in developing this model dipole is to test a method of stress management in which Lorentz stress is intercepted within the coil assembly and bypassed so that it cannot accumulate to a level that would cause strain degradation in the superconducting windings. Details of the fabrication, tooling, and results of construction and magnet component testing will be presented.

  7. Structurally abnormal human autosomes

    SciTech Connect

    1993-12-31

    Chapter 25, discusses structurally abnormal human autosomes. This discussion includes: structurally abnormal chromosomes, chromosomal polymorphisms, pericentric inversions, paracentric inversions, deletions or partial monosomies, cri du chat (cat cry) syndrome, ring chromosomes, insertions, duplication or pure partial trisomy and mosaicism. 71 refs., 8 figs.

  8. Recent Advances in Modeling Stress Distributions in Multilayers Subjected to Biaxial Flexure Tests

    SciTech Connect

    Hsueh, Chun-Hway; Luttrell, Claire Roberta

    2007-01-01

    Although biaxial flexure tests have been used extensively to measure the strength of brittle materials, the tests and analyses have been limited to materials of uniform properties. Despite the increasing applications of multilayered structures, characterization of their strengths using biaxial flexure tests has been difficult because the analytical description of the strength-fracture load relation for multilayers subjected to biaxial flexure tests is unavailable. The newly derived closed-form solutions for the elastic stress distributions in multilayered discs subjected to ring-on-ring tests are summarized here. These solutions are obtained by (i) finding the correlation between monolayered and multilayered discs subjected to biaxial bending moment and (ii) conversion from the existing solutions for monolayers. Using this methodology, the closed-form solutions for multilayers subjected to other biaxial flexure tests can also be obtained. Finite element results for ring-on-rings tests performed on (i) porcelain/zirconia bilayered discs and (ii) solid oxide fuel cells trilayered discs are also presented to validate the closed-form solutions. The closed-form solutions hence provide a basis for evaluating biaxial strength of multilayers using biaxial flexure tests.

  9. Electric vehicle dynamic-stress-test cycling performance of lithium-ion cells

    NASA Astrophysics Data System (ADS)

    Mayer, S. T.

    1994-05-01

    Dynamic Stress tests (DST) of small lithium-ion cells have demonstrated that the systems delivers high energy (65 Wh/kg, 4.3 hours runtime) with reasonable cycle-life (375-480 cycles) under the full USABC mid-term dynamic-stress-test conditions (150 W/kg). At lower depth-of-discharge substantially higher cycle life was observed (2800 cycles at 44% depth of discharge, 1.9 hours runtime). Both the depth of discharge and charging voltage V(sub c) (4.1 V less than V(sub c) less than 4.2 V) affect the delivered energy and cell life in an interacting manner. At high depth of discharge (greater tha n 80%), a lower V(sub c) is preferred because it maximize cycle life with a small penalty in energy. At intermediate depth of discharge (40--80%), a higher V(sub c) is preferred. Long-term tests are needed to determine the DST cycle life at very low depth of discharge(less than 40%). The high power pulse of the DST test limits the delivered cell energy and life. If a high energy density load-leveling technology is developed (e.g. flywheels or double layer capacitors) the delivered energy and cycle life could be substantially increased.

  10. Morphological abnormalities among lampreys

    USGS Publications Warehouse

    Manion, Patrick J.

    1967-01-01

    The experimental control of the sea lamprey (Petromyzon marinus) in the Great Lakes has required the collection of thousands of lampreys. Representatives of each life stage of the four species of the Lake Superior basin were examined for structural abnormalities. The most common aberration was the presence of additional tails. The accessory tails were always postanal and smaller than the normal tail. The point of origin varied; the extra tails occurred on dorsal, ventral, or lateral surfaces. Some of the extra tails were misshaped and curled, but others were normal in shape and pigment pattern. Other abnormalities in larval sea lampreys were malformed or twisted tails and bodies. The cause of the structural abnormalities is unknown. The presence of extra caudal fins could be genetically controlled, or be due to partial amputation or injury followed by abnormal regeneration. Few if any lampreys with structural abnormalities live to sexual maturity.

  11. Determination of the flow stress of a magnetorheological fluid under three-dimensional stress states by using a combination of extrusion test and FEM simulation

    NASA Astrophysics Data System (ADS)

    Wang, Peng-yi; Wang, Zhong-jin

    2016-12-01

    Magnetorheological fluid (MR fluid), a kind of smart material, has been used as a new pressure-carrying medium in magnetorheological pressure forming (MRPF). The mechanical property of MR fluid under the pressure significantly affects the sheet formability. However, there is little knowledge on the deformation behavior of MR fluid under three-dimensional stress states. In this paper, a new procedure via a combination of extrusion test and FEM simulation has been proposed to determine the flow stress of MR fluids. The experimental device for extrusion test of MR fluids was designed. The flow stresses of a MR fluid (MRF-J01T) under four different magnetic fields were determined through the proposed procedure. In addition, the obtained flow stresses were used in the following FEM simulations to verify the accuracy by comparing with the experimental results. The simulation results were in good agreement with the experimental data, which supports the correctness and practicability of the proposed method.

  12. Melatonin alleviates cadmium-induced cellular stress and germ cell apoptosis in testes.

    PubMed

    Ji, Yan-Li; Wang, Hua; Meng, Can; Zhao, Xian-Feng; Zhang, Cheng; Zhang, Ying; Zhao, Mei; Chen, Yuan-Hua; Meng, Xiu-Hong; Xu, De-Xiang

    2012-01-01

    Increasing evidence demonstrates that melatonin has an anti-apoptotic effect in somatic cells. However, whether melatonin can protect against germ cell apoptosis remains obscure. Cadmium (Cd) is a testicular toxicant and induces germ cell apoptosis. In this study, we investigated the effects of melatonin on Cd-evoked germ cell apoptosis in testes. Male ICR mice were intraperitoneally (i.p.) injected with melatonin (5 mg/kg) every 8 hr, beginning at 8 hr before CdCl(2) (2.0 mg/kg, i.p.). As expected, acute Cd exposure resulted in germ cell apoptosis in testes, as determined by terminal dUTP nick-end labeling (TUNEL) staining. Melatonin significantly alleviated Cd-induced testicular germ cell apoptosis. An additional experiment showed that spliced form of XBP-1, the target of the IRE-1 pathway, was significantly increased in testes of mice injected with CdCl(2). GRP78, an endoplasmic reticulum (ER) chaperone, and CHOP, a downstream target of the PERK pathway, were upregulated in testes of Cd-treated mice. In addition, acute Cd exposure significantly increased testicular eIF2α and JNK phosphorylation, indicating that the unfolded protein response (UPR) pathway was activated by CdCl(2). Interestingly, melatonin almost completely inhibited Cd-induced ER stress and the UPR in testes. In addition, melatonin obviously attenuated Cd-induced heme oxygenase (HO)-1 expression and protein nitration in testes. Taken together, these results suggest that melatonin alleviates Cd-induced cellular stress and germ cell apoptosis in testes. Melatonin may be useful as pharmacological agents to protect against Cd-induced testicular toxicity. PMID:21793897

  13. [Endocrine abnormalities in HIV infections].

    PubMed

    Verges, B; Chavanet, P; Desgres, J; Kisterman, J P; Waldner, A; Vaillant, G; Portier, H; Brun, J M; Putelat, R

    The finding of endocrine gland lesions at pathological examination in AIDS and reports of several cases of endocrine disease in patients with this syndrome have prompted us to study endocrine functions in 63 patients (51 men, 12 women) with HIV-1 infection. According to the Center for Disease Control (CDC) classification system, 13 of these patients were stage CDC II, 27 stage CDC III and 23 stage CDC IV. We explored the adrenocortical function (ACTH, immediate tetracosactrin test) and the thyroid function (free T3 and T4 levels, TRH on TSH test) in all 63 patients. The hypothalamic-pituitary-gonadal axis (testosterone levels, LHRH test) and prolactin secretion (THR test) were explored in the 51 men. The results obtained showed early peripheral testicular insufficiency at stage CDC II and early pituitary gland abnormalities with hypersecretion of ACTH and prolactin also at stage CDC II. On the other hand, adrenocortical and pituitary abnormalities were not frequently found. The physiopathology of the endocrine abnormalities observed in HIV-1-infected patients remains unclear, but one may suspect that it involves interleukin-1 since this protein factor has recently been shown to stimulate the corticotropin-releasing hormone secretion and to act directly on the glycoprotein capsule of the virus (gp 120) whose structure is similar to that of some neurohormones.

  14. Social Support for Divorced Fathers' Parenting: Testing a Stress-Buffering Model*

    PubMed Central

    DeGarmo, David S.; Patras, Joshua; Eap, Sopagna

    2008-01-01

    A stress-buffering hypothesis for parenting was tested in a county-representative sample of 218 divorced fathers. Social support for parenting (emergency and nonemergency child care, practical support, financial support) was hypothesized to moderate effects of stress (role overload, coparental conflict, and daily hassles) on fathers’ quality parenting. No custody fathers relied more on relatives compared with custodial fathers, who relied more on new partners for parenting support. No differences by custody status were found on levels of support or parenting over time. Parenting support buffered effects of change in role overload and coparenting conflict on coercive parenting and buffered effects of change in daily hassles on prosocial parenting. Buffer effects were more predictive over time. Implications for practice and preventive intervention strategies are discussed. PMID:19177181

  15. A Qualitative Comparison of the C-Ring Test and the Jones Test as Standard Practice Test Methods for Studying Stress Corrosion Cracking in Ferritic Steels

    SciTech Connect

    Thomson, Jeffery K; Pawel, Steven J

    2015-01-01

    Creep-strength-enhanced-ferritic (CSEF) steels have been widely implemented as water wall alloy materials in the coal-fired power industry for many years. The stress corrosion cracking (SCC) behavior of this class of materials is currently of significant interest to the industry due to recent failures. To better understand the test methods used to characterize SCC behavior in the laboratory, three representative CSEF alloys (T23, T24, and T92) were subjected to two SCC test protocols: the Jones Test set forth in DIN 50915, and the C-ring SCC test set forth in ASTM G38-01. Samples were tested in either the as-received (normalized + tempered) condition or in the normalized condition (quenched from 1065 C). Samples were exposed to aerated water in one test case and de-aerated water in a second test case for a period of 7 days at 200 C. It was found that for both test protocols, the normalized condition with aerated water led to severe cracking for all three alloys, whereas no evidence of cracking was found for the other conditions.

  16. Comparative Stress Corrosion Cracking and General Corrosion Resistance of Annealed and Hardened 440 C Stainless Steel - New Techniques in Stress Corrosion Testing

    NASA Technical Reports Server (NTRS)

    Mendreck, M. J.; Hurless, B. E.; Torres, P. D.; Danford, M. D.

    1998-01-01

    The corrosion and stress corrosion cracking (SCC) characteristics of annealed and hardened 440C stainless steel were evaluated in high humidity and 3.5-percent NaCl solution. Corrosion testing consisted of an evaluation of flat plates, with and without grease, in high humidity, as well as electrochemical testing in 3.5-percent NaCl. Stress corrosion testing consisted of conventional, constant strain, smooth bar testing in high humidity in addition to two relatively new techniques under evaluation at MSFC. These techniques involve either incremental or constant rate increases in the load applied to a precracked SE(B) specimen, monitoring the crack-opening-displacement response for indications of crack growth. The electrochemical corrosion testing demonstrated an order of magnitude greater general corrosion rate in the annealed 440C. All techniques for stress corrosion testing showed substantially better SCC resistance in the annealed material. The efficacy of the new techniques for stress corrosion testing was demonstrated both by the savings in time and the ability to better quantify SCC data.

  17. Acute heat stress induces differential gene expressions in the testes of a broiler-type strain of Taiwan country chickens.

    PubMed

    Wang, Shih-Han; Cheng, Chuen-Yu; Tang, Pin-Chi; Chen, Chih-Feng; Chen, Hsin-Hsin; Lee, Yen-Pai; Huang, San-Yuan

    2015-01-01

    The expression of testicular genes following acute heat stress has been reported in layer-type roosters, but few similar studies have been conducted on broilers. This study investigated the effect of acute heat stress on the gene expression in the testes of a broiler-type strain of Taiwan country chickens. Roosters were subjected to acute heat stress (38°C) for 4 h, and then exposed to 25°C, with testes collected 0, 2, and 6 h after the cessation of heat stress, using non-heat-stressed roosters as controls (n = 3 roosters per group). The body temperature and respiratory rate increased significantly (p<0.05) during the heat stress. The numbers of apoptotic cells increased 2 h after the acute heat stress (79 ± 7 vs. 322 ± 192, control vs. heat stress; p<0.05), which was earlier than the time of increase in layer-type roosters. Based on a chicken 44 K oligo microarray, 163 genes were found to be expressed significantly different in the testes of the heat-stressed chickens from those of the controls, including genes involved in the response to stimulus, protein metabolism, signal transduction, cell adhesion, transcription, and apoptosis. The mRNA expressions of upregulated genes, including HSP25, HSP90AA1, HSPA2, and LPAR2, and of downregulated genes, including CDH5, CTNNA3, EHF, CIRBP, SLA, and NTF3, were confirmed through quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, numerous transcripts in the testes exhibited distinct expressions between the heat-stressed broiler-type and layer-type chickens. We concluded that the transcriptional responses of testes to acute heat stress may differ between the broiler-type and layer-type roosters. Whether the differential expression patterns associate with the heat-tolerance in the strains require a further exploration.

  18. Finding the Gatekeeper to the Cardiac Catheterization Laboratory: Coronary CT Angiography or Stress Testing?

    PubMed

    Marwick, Thomas H; Cho, Iksung; Ó Hartaigh, Bríain; Min, James K

    2015-06-30

    Functional capacity is a robust predictor of clinical outcomes, and stress testing is used in current practice paradigms to guide referral to invasive coronary angiography. However, invasive coronary angiography is driven by ongoing symptoms, as well as risk of adverse outcomes. The limitations of current functional testing-based paradigms might be avoided by using coronary computed tomographic angiography (CCTA) for exclusion of obstructive coronary artery disease. The growth of CCTA has been supported by comparative prognostic evidence with CCTA and functional testing, as well as radiation dose reduction. Use of CCTA for physiological evaluation of coronary lesion-specific ischemia may facilitate evaluation of moderate stenoses, designation of the culprit lesion, and prediction of benefit from revascularization. The potential of CCTA to serve as an effective gatekeeper to invasive coronary angiography will depend, in part, on the adoption of these new developments, as well as definition of the benefit of detecting high-risk plaque for guiding the management of selected patients.

  19. Stress, Social Support, and Depression: A Test of the Stress-Buffering Hypothesis in a Mexican Sample

    ERIC Educational Resources Information Center

    Raffaelli, Marcela; Andrade, Flavia C. D.; Wiley, Angela R.; Sanchez-Armass, Omar; Edwards, Laura L.; Aradillas-Garcia, Celia

    2013-01-01

    This study examined social support as a potential moderator between stress and depressive symptoms among Mexican university applicants aged 16--21 years ("N" = 6,715; "M" age = 17.9 years; 55% female). In bivariate analyses, perceived stress was associated with higher levels of depressive symptoms, and social support with lower…

  20. Diagnostic Value of Electrocardiogram in Predicting Exaggerated Blood Pressure Response to Exercise Stress Testing

    PubMed Central

    Eshraghi, Ali; Ebdali, Reyhaneh Takalloo; Sajjadi, Seyed Sajed; Golnezhad, Reza

    2016-01-01

    Introduction It is believed that an exaggerated blood pressure response (EBPR) to exercise stress test is associated with a higher risk of cardiovascular events. It is also assumed that QT dispersion (QT-d), which was originally proposed to measure the spatial dispersion of ventricular recovery times, may have a relationship to cardiovascular events. The objective of this study was to examine the difference of changes in QT-d, Maxi-QT, Mini-QT, and QT-c (corrected QT interval) of the electrocardiogram in two groups of patients with exaggerated blood pressure responses (EBPR group) and normal responses (control group) to exercise testing. Also, the diagnostic value of each of these criteria in the prediction of EBPR was studied. Methods This cross-sectional study was conducted from May 2015 to February 2016 on patients suspected of coronary artery disease (CAD) undergoing exercise testing who had been referred to Ghaem and Imam Reza hospitals in Mashhad (Iran). All patients underwent a treadmill exercise test with the 12-lead ECG, which was optically scanned and digitized for analysis of QT-d, QT max, and QT min. Patients were divided into two groups of normal and EBPR to exercise testing. QT changes of ECG were compared between the two groups, and the diagnostic accuracy of QT variables for prediction of EBPR to exercise testing was studied. A multiple linear regression analysis (MLR), Pearson Chi-qquare, independent samples t-test, and receiver operating characteristic (ROC) curve were used as statistical methods in IBM SPSS version 19. Results Sixty patients (55% male) with a mean age of 50.48 ± 10.89 years were studied in two groups of normal (n=30) and exaggerated blood pressure response (n=30) to exercise testing. Maximum QT and QT dispersion were statistically different in individuals’ exaggerated blood pressure response to exercise stress test (p < 0.05). The logistic regression analysis revealed that none of our parameters predicted the EBPR. The ROC

  1. Estimation of In Situ Stress and Permeability from an Extended Leak-off Test

    NASA Astrophysics Data System (ADS)

    Nghiep Quach, Quoc; Jo, Yeonguk; Chang, Chandong; Song, Insun

    2016-04-01

    Among many parameters needed to analyze a variety of geomechanical problems related to subsurface CO2 storage projects, two important ones are in situ stress states and permeability of the storage reservoirs and cap rocks. In situ stress is needed for investigating potential risk of fault slip in the reservoir systems and permeability is needed for assessing reservoir flow characteristics and sealing capability of cap rocks. We used an extended leak-off test (XLOT), which is often routinely conducted to assess borehole/casing integrity as well as fracture gradient, to estimate both in situ least principal stress magnitude and in situ permeability in a CO2 storage test site, offshore southeast Korea. The XLOT was conducted at a casing shoe depth (700 m below seafloor) within the cap rock consisting of mudstone, approximately 50 m above the interface between cap rock and storage reservoir. The test depth was cement-grouted and remained for 4 days for curing. Then the hole was further drilled below the casing shoe to create a 4 m open-hole interval at the bottom. Water was injected using hydraulic pump at an approximately constant flowrate into the bottom interval through the casing, during which pressure and flowrate were recorded continuously at the surface. The interval pressure (P) was increased linearly with time (t) as water was injected. At some point, the slope of P-t curve deviated from the linear trend, which indicates leak-off. Pressure reached its peak upon formation breakdown, followed by a gradual pressure decrease. Soon after the formation breakdown, the hole was shut-in by pump shut-off, from which we determined the instantaneous shut-in pressure (ISIP). The ISIP was taken to be the magnitude of the in situ least principal stress (S3), which was determined to be 12.1 MPa. This value is lower than the lithostatic vertical stress, indicating that the S3 is the least horizontal principal stress. The determined S3 magnitude will be used to characterize the

  2. 12 CFR 1238.5 - Required report to FHFA and the FRB of stress test results and related information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... FHFA property and records (as defined in 12 CFR part 1202 of this chapter). The reports are and include... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Required report to FHFA and the FRB of stress... AGENCY ENTITY REGULATIONS STRESS TESTING OF REGULATED ENTITIES § 1238.5 Required report to FHFA and...

  3. Test Results of a Nb3Sn Wind/React 'Stress-Managed' BlockDipole

    SciTech Connect

    McInturff, A.; Bish, P.; Blackburn, R.; Diaczenko, N.; Elliott,T.; Hafalia Jr., R.; Henchel, W.; Jaisle, A.; Lau, W.; Lietzke, A.; McIntyre, P.; Noyes, P.; Nyman, M.; Sattarov, A.; Sattarov, A.

    2006-08-25

    A second phase of a highfield dipole technology developmenthas been tested. A Nb3Sn block-coil model dipole was fabricated, usingmagnetic mirror geometry and wind/react coil technology. The primaryobjective of this phase was to make a first experimental test of thestress-management strategy pioneered at Texas A&M. In this strategy ahigh-strength support matrix is integrated with the windings to interceptLorentz stress from the inner winding so that it does not accumulate inthe outer winding. The magnet attained a field that was consistent withshort sample limit on the first quench; there was no training. Thedecoupling of Lorentz stress between inner and outer windings wasvalidated. In ramp rate studies the magnet exhibited a remarkablerobustness in rapid ramping operation. It reached 85 percent of shortsample(ss) current even while ramping 2-3 T/s. This robustness isattributed to the orientation of the Rutherford cables parallel to thefield in the windings, instead of the transverse orientation thatcharacterizes common dipole designs. Test results are presented and thenext development phase plans are discussed.

  4. Effect of competition stress on tests used to assess testosterone administration in athletes.

    PubMed

    Guezennec, C Y; Lafarge, J P; Bricout, V A; Merino, D; Serrurier, B

    1995-08-01

    The drug test for exogenous administration of testosterone is based on the testosterone/epitestosterone ratio (T/E) in urine. Physiological and psychological stresses may alter plasma testosterone concentrations. The question is to know how much the psychological conditions of competition can modify the T/E ratio. In order to study this issue, 20 athletes practising modern pentathlon participated in a study designed to determine the effects of a pistol shooting trial on their hormonal response. Pistol shooting induces a high psychological stress without increasing energy expenditure. Venous blood samples were drawn before and after the trial according to the usual drug testing procedure. Athletes were separated into two groups: a group of young athletes (n = 10; mean age 19 +/- 0.3 years) and another group of aged subjects (n = 10; mean age 45 +/- 1.5 years). The rise in plasma testosterone concentrations reached 75% in older subjects versus 55% in younger ones. The plasma luteinizing hormone (LH) concentrations were not influenced by the trial. After shooting trial the elevation in cortisol concentrations was greater for older subjects than for younger ones (273 +/- 30 ng.ml-1 vs 173 +/- 7 ng.ml-1). The catecholamine response was identical in both groups. The urinary T/E ratio remained unchanged after the shooting trial and always remained lower than the International Olympic Committee limit of 6. These results indicate that the psychological stress associated with competition increases the production of steroid hormones (testosterone, cortisol), and that this phenomenon is more pronounced in older athletes. These hormonal changes do not influence the urinary excretion of steroid metabolites used as criterion for drug testing.

  5. Stress Rupture Testing and Analysis of the NASA WSTF-JPL Carbon Overwrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

    Greene, Nathanael; Yoder, Tommy; Saulsberry, Regor; Grimes, Lorie; Thesken, John; Phoenix, Leigh

    2007-01-01

    Carbon composite overwrapped pressure vessels (COPVs) are widely used in applications from spacecraft to life support. COPV technology provides a pressurized media storage advantage over amorphous technology with weight savings on the order of 30 percent. The National Aeronautics and Space Administration (NASA) has been supporting the development of this technology since the early 1970's with an interest in safe application of these components to reduce mass to orbit. NASA White Sands Test Facility (WSTF) has been testing components in support of this objective since the 1980s and has been involved in test development and analysis to address affects of impact, propellant and cryogenic fluids exposure on Kevlar and carbon epoxy. The focus of this paper is to present results of a recent joint WSTF-Jet Propulsion Laboratories (JPL) effort to assess safe life of these components. The WSTF-JPL test articles consisted of an aluminum liner and a carbon fiber overwrap in an industry standard epoxy resin system. The vessels were specifically designed with one plus-minus helical wrap and one hoop wrap over the helical and they measured 4.23 x 11.4 in. long. 120 test articles were manufactured in August of 1998 of one lot fiber and resin and the 110 test articles were delivered to WSTF for test. Ten of the 120 test articles were burst tested at the manufacturer to establish the delivered fiber stress. Figure 1 shows a test article in a pre burst condition and with a hoop fiber failure (no leak of pressurized media) and post burst (failure of liner and loss of pressurized media).

  6. Abnormal uterine bleeding.

    PubMed

    Jennings, J C

    1995-11-01

    Physicians who care for female patients cannot avoid the frequent complaint of abnormal uterine bleeding. Knowledge of the disorders that cause this problem can prevent serious consequences in many patients and improve the quality of life for many others. The availability of noninvasive and minimally invasive diagnostic studies and minimally invasive surgical treatment has revolutionized management of abnormal uterine bleeding. Similar to any other disorder, the extent to which a physician manages abnormal uterine bleeding depends on his or her own level of comfort. When limitations of either diagnostic or therapeutic capability are encountered, consultation and referral should be used to the best interest of patients.

  7. Strain measurements using FBG on composite over wrap pressure vessels (COPV) in stress rupture test

    NASA Astrophysics Data System (ADS)

    Grant, Joseph; Banks, Curtis

    2007-04-01

    Thirty six Fiber Optic Braggs Grating sensors were used during an ambient temperature hydrostatic pressurization testing of a Space Transportation System (STS) 40-inch Kevlar Composite Over-wrapped Pressure Vessel (COPV). The 40-inch vessel was of the same design and approximate age as the STS Main Propulsion System (MPS) and Orbiter Maneuvering System (OMS) vessels. The sensors were surfaces mounted to on the vessel to measure strain during a stress rupture event. The Bragg signals were linear with the applied pressure. The results indicated that the vessel was under an uneven force distribution at various locations on the vessel.

  8. EXPERT PANEL OVERSIGHT COMMITTEE ASSESSMENT OF FY2008 CORROSION AND STRESS CORROSION CRACKING SIMULANT TESTING PROGRAM

    SciTech Connect

    BOOMER KD

    2009-01-08

    The Expert Panel Oversight Committee (EPOC) has been overseeing the implementation of selected parts of Recommendation III of the final report, Expert Panel workshop for Hanford Site Double-Shell Tank Waste Chemistry Optimization, RPP-RPT-22126. Recommendation III provided four specific requirements necessary for Panel approval of a proposal to revise the chemistry control limits for the Double-Shell Tanks (DSTs). One of the more significant requirements was successful performance of an accelerated stress corrosion cracking (SCC) experimental program. This testing program has evaluated the optimization of the chemistry controls to prevent corrosion in the interstitial liquid and supernatant regions of the DSTs.

  9. Residual stress analysis on tensile MMC specimens after loading/unloading tests in several conditions

    NASA Astrophysics Data System (ADS)

    Giuliani, Alessandra; Albertini, Gianni; Manescu, Adrian

    2004-07-01

    Residual stresses have been investigated in samples made of AA6061+22% Al2O3 in order to correlate microstructural characteristics with mechanical performances. In particular, the possible occurrence of a brittle fracture induced by an excessive load transfer from the matrix to the reinforcement was investigated. To this end, macrostresses and microstresses were analysed. A neutron diffraction test on 12 specimens submitted to several loading/unloading conditions at different temperatures was performed. These measurements aimed to establish the optimal temperature for the initial extruded billet in pre-heating stage, before forging the final wheel hub.

  10. Thallium-201 perfusion imaging with atrial pacing or dipyridamole stress testing for evaluation of cardiac risk prior to nonvascular surgery

    SciTech Connect

    Stratmann, H.G.; Mark, A.L.; Williams, G.A. )

    1990-09-01

    Preoperative assessment of cardiac risk using thallium-201 scintigraphy and atrial pacing (n = 42) or dipyridamole stress testing (n = 35) was performed in 77 patients (mean age 65 +/- 7 years), who subsequently underwent elective nonvascular surgery. All patients were at low cardiac risk by clinical criteria; none could perform exercise stress testing due to physical limitations. ST depression consistent with ischemia occurred in 11 patients during atrial pacing and in 1 patient during dipyridamole stress testing (p less than 0.01). Nine patients had reversible perfusion defects with atrial pacing, and 10 patients with dipyridamole stress testing; fixed defects were present in 15 and 8 patients, respectively. Only one patient (fixed perfusion defect with atrial pacing, left main disease on coronary angiography) underwent preoperative coronary revascularization. Two patients subsequently had postoperative cardiac events. One patient (reversible perfusion defect with dipyridamole stress testing) experienced sudden death after a nonvascular procedure, while a second patient (normal thallium images with dipyridamole testing) had a nonfatal myocardial infarction. In patients having atrial pacing or dipyridamole stress testing, thallium-201 scans that are normal or show only a fixed perfusion defect confirm a low risk of cardiac complications following nonvascular surgery. The presence of a reversible perfusion defect does not preclude a postoperative course free of cardiac complications in patients at low cardiac risk by clinical criteria.

  11. The stress-corrosion behavior of Al-Li-Cu alloys: A comparison of test methods

    NASA Technical Reports Server (NTRS)

    Rizzo, P. P.; Galvin, R. P.; Nelson, H. G.

    1982-01-01

    Two powder metallurgy processed (Al-Li-Cu) alloys with and without Mg addition were studied in aqueous 3.5% NaCl solution during the alternate immersion testing of tuning fork specimens, slow crack growth tests using fracture mechanics specimens, and the slow strain rate testing of straining electrode specimens. Scanning electron microscopy and optical metallography were used to demonstrate the character of the interaction between the Al-Li-Cu alloys and the selected environment. Both alloys are susceptible to SC in an aqueous 3.5% NaCl solution under the right electrochemical and microstructural conditions. Each test method yields important information on the character of the SC behavior. Under all conditions investigated, second phase particles strung out in rows along the extrusion direction in the alloys were rapidly attacked, and played principal role in the SC process. With time, larger pits developed from these rows of smaller pits and under certain electrochemical conditions surface cracks initiated from the larger pits and contributed directly to the fracture process. Evidence to support slow crack growth was observed in both the slow strain rate tests and the sustained immersion tests of precracked fracture mechanics specimens. The possible role of H2 in the stress corrosion cracking process is suggested.

  12. Residual stress in the cylindrical drawing cup of SUS304 stainless steel evaluated by split-ring test

    NASA Astrophysics Data System (ADS)

    Xiao, Liang-Hong; Yuan, Dao-He; Xiang, Jun-Zhong; Liu, Jin-Gang; Zhou, Yi-Chun

    2016-02-01

    The residual stresses in the wall of a SUS304 stainless steel cylindrical drawing cup were evaluated by split-ring tests, and the influences of stamping die parameters on the residual stress were investigated. A new theoretical model of a split-ring test was developed to evaluate the residual stress in a ring, which was verified to be reasonable and reliable by numerical simulations with ABAQUS code and by nanoindentation tests. Seven groups of split-ring tests were completed, and the residual stresses were calculated according to the theoretical model. The split-ring test results showed that the circumferential residual stress in the wall of the SUS304 stainless steel cylindrical drawing cup was very large and did not change with the different die corner radius. The circumferential residual stress first increased with the increase of drawing punch-die clearance, then was almost unchanged when the clearance increased greater than blank thickness 1 mm. Thus, a smaller clearance was suggested to be chosen to reduce the residual stress in the wall of the SUS304 stainless steel drawing cup.

  13. Flight Tests on U.S.S. Los Angeles. Part II : Stress and Strength Determination

    NASA Technical Reports Server (NTRS)

    Burgess, C P

    1930-01-01

    The tests described in this report furnished data on the actual aerodynamic forces, and the resulting stresses and bending moments in the hull of the U. S. S. "Los Angeles" during as severe still-air maneuvers as the airship would normally be subjected to, and in straight flight during as rough air as is likely to occur in service, short of squall or storm conditions. The maximum stresses were found to be within the limits provided for in accepted practice in airship design. Normal flight in rough air was shown to produce forces and stresses about twice as great as the most severe still-air maneuvers. No light was thrown upon the forces which might occur in extreme or exceptional conditions, such as the storm which destroyed the "Shenandoah". The transverse aerodynamic forces on the hull proper were found to be small and irregular. Owing to the necessity of conserving helium, it was impossible to fly the airship in a condition of large excess of buoyancy or weight in order to determine the air pressure distribution at a fixed angle of pitch. However, there is every reason to believe that in that condition the forces on the actual airship are as close to the wind-tunnel results as can be determined by present type of pressure measuring apparatus. It is considered that most important data obtained are the coefficients of tail-surface forces and hull-bending moments. These are tabulated in this report.

  14. Testing the Relationship between Human Occupancy in the Landscape and Tadpole Developmental Stress

    PubMed Central

    Eterovick, Paula C.; Bar, Luís F. F.; Souza, Jorge B.; Castro, José F. M.; Leite, Felipe S. F.; Alford, Ross A.

    2015-01-01

    Amphibian population declines are widespread; the main causal factors are human related and include habitat fragmentation due to agriculture, mining, fires, and urban development. Brazil is the richest country in species of amphibians, and the Brazilian regions with the greatest amphibian diversity are experiencing relatively high rates of habitat destruction, but there are presently relatively few reports of amphibian declines. It is thus important to develop research methods that will detect deterioration in population health before severe declines occur. We tested the use of measurements of fluctuating asymmetry (FA) taken on amphibian larvae to detect anthropogenic stress. We hypothesized that greater human occupancy in the landscape might result in more stressful conditions for amphibians. We conducted this study at the Espinhaço mountain range in southeastern Brazil, using as a model an endemic species (Bokermannohyla saxicola, Hylidae). We chose two tadpole denticle rows and eye-nostril distance as traits for FA measurement. We measured percent cover of human-altered habitats in the landscape around tadpole sampling points and measured FA levels in sampled tadpoles. We found FA levels to differ among localities but found no relationship between human modification of the landscape and tadpole FA levels. Levels of FA in the traits we examined may not be strongly affected by environmental conditions, or may be affected by local variables that were not captured by our landscape-scale measures. Alternatively, populations may be genetically differentiated, affecting how FA levels respond to stress and obscuring the effects of anthropogenic disturbance. PMID:25793699

  15. Testing the relationship between human occupancy in the landscape and tadpole developmental stress.

    PubMed

    Eterovick, Paula C; Bar, Luís F F; Souza, Jorge B; Castro, José F M; Leite, Felipe S F; Alford, Ross A

    2015-01-01

    Amphibian population declines are widespread; the main causal factors are human related and include habitat fragmentation due to agriculture, mining, fires, and urban development. Brazil is the richest country in species of amphibians, and the Brazilian regions with the greatest amphibian diversity are experiencing relatively high rates of habitat destruction, but there are presently relatively few reports of amphibian declines. It is thus important to develop research methods that will detect deterioration in population health before severe declines occur. We tested the use of measurements of fluctuating asymmetry (FA) taken on amphibian larvae to detect anthropogenic stress. We hypothesized that greater human occupancy in the landscape might result in more stressful conditions for amphibians. We conducted this study at the Espinhaço mountain range in southeastern Brazil, using as a model an endemic species (Bokermannohyla saxicola, Hylidae). We chose two tadpole denticle rows and eye-nostril distance as traits for FA measurement. We measured percent cover of human-altered habitats in the landscape around tadpole sampling points and measured FA levels in sampled tadpoles. We found FA levels to differ among localities but found no relationship between human modification of the landscape and tadpole FA levels. Levels of FA in the traits we examined may not be strongly affected by environmental conditions, or may be affected by local variables that were not captured by our landscape-scale measures. Alternatively, populations may be genetically differentiated, affecting how FA levels respond to stress and obscuring the effects of anthropogenic disturbance. PMID:25793699

  16. Testing the stress gradient hypothesis in herbivore communities facilitation peaks at intermediate nutrient levels.

    PubMed

    Bakker, Elisabeth S; Dobrescu, Ioana; Straile, Dietmar; Holmgren, Milena

    2013-08-01

    The role of positive interactions in structuring plant and animal communities is increasingly recognized, but the generality of current theoretical models has remained practically unexplored in animal communities. The stress gradient hypothesis predicts a linear increase in the intensity of facilitation as environmental conditions become increasingly stressful, whereas other theoretical models predict a maximum at intermediate environmental stress. We tested how competition and facilitation between herbivores change over a manipulated gradient of nutrient availability. We studied the effect of grazing by pond snails (Lymnaea stagnalis L.) as bulk grazers on aquatic caterpillars (Acentria ephemerella Denis and Schiffermüller) as small specialist grazers along an experimental gradient of environmental nutrient concentration. Higher nutrient levels increased overall total plant biomass but induced a shift toward dominance of filamentous algae at the expense of macrophytes. Facilitation of caterpillars by snail presence peaked at intermediate nutrient levels. Both caterpillar biomass and caterpillar grazing on macrophytes were highest at intermediate nutrient levels. Snails facilitated caterpillars possibly by removing filamentous algae and increasing access to the macrophyte resource, whereas they did not affect macrophyte biomass or C: nutrient ratios, a measure of food quality. We conclude that competition and facilitation in herbivore communities change along nutrient availability gradients that affect plant biomass and community composition. Understanding how interspecific interactions may change in strength and direction along environmental gradients is important to predict how the diversity and structure of communities may respond to the introduction or removal of herbivore species in ecosystems. PMID:24015521

  17. Thymoquinone supplementation reverses lead-induced oxidative stress in adult rat testes.

    PubMed

    Mabrouk, Aymen; Ben Cheikh, Hassen

    2015-01-01

    The purpose of the present study was to investigate the potential protective effect of thymoquinone (TQ), the major active ingredient of volatile oil of Nigella sativa seeds, against Pb-induced testicular oxidative stress. Adult male rats were randomized into four groups: control group which received no treatment, Pb group was exposed to 2000 ppm Pb acetate in drinking water, Pb-TQ group was co-treated with Pb plus TQ (5 mg/kg b.w./day, p.o.) and TQ group receiving only TQ (5 mg/kg b.w./day, p.o.). All treatments were applied for 5 weeks. Pb treatment induced oxidative stress status in testes as evidenced by a significant decrease in the antioxidant enzymes activities such as superoxide dismutase, glutathione peroxidase and catalase, and in the reduced glutathione content and in a significant increase in the level of malondialdehyde. Interestingly, TQ supplementation completely reversed these biochemical changes caused by Pb to the control values. In conclusion, our results suggest, for the first time, that TQ is very efficient in preventing Pb-induced testicular oxidative stress. This study will open new perspectives for the clinical use of TQ in Pb intoxication. PMID:25367764

  18. Rapid formulation assessment of filgrastim therapeutics by a thermal stress test.

    PubMed

    Alebouyeh, Mahmoud; Tahzibi, Abbas; Yaghoobzadeh, Sareh; Zahedy, Elnaz Tamaskany; Kiumarsi, Shiva; Soltanabad, Mojtaba Hadi; Shahbazi, Saleh; Amini, Hossein

    2016-05-01

    The biosimilar versions of recombinant methionyl human granulocyte colony-stimulating factor (rh-Met-G-CSF, filgrastim) are now widely available. Because changes to the formulation often lead to subtle differences, there is a critical need to define techniques to test and insure the quality of these products. The present study was designed to compare formulation and thermal stress stability of filgrastim products. The formulation ingredients including acetate, polysorbate 80, and sorbitol were determined using state-of-the-art validated analytical methods. The formulation pH and osmolality were also measured. Moreover, the stability profiles of 8 filgrastim products using thermal stress at 57 °C for 4 h were assessed by size-exclusion high-performance liquid chromatography (SE-HPLC) and in vitro biological assay. The products had different stability profiles. More stable products were within the specification for formulation and less stable products were beyond the specification limits. Altogether, the results suggest that a short-time stress study at 57 °C and analysis of filgrastim by SE-HPLC could unveil formulation problems and is potentially useful for comparability studies.

  19. Thymoquinone supplementation reverses lead-induced oxidative stress in adult rat testes.

    PubMed

    Mabrouk, Aymen; Ben Cheikh, Hassen

    2015-01-01

    The purpose of the present study was to investigate the potential protective effect of thymoquinone (TQ), the major active ingredient of volatile oil of Nigella sativa seeds, against Pb-induced testicular oxidative stress. Adult male rats were randomized into four groups: control group which received no treatment, Pb group was exposed to 2000 ppm Pb acetate in drinking water, Pb-TQ group was co-treated with Pb plus TQ (5 mg/kg b.w./day, p.o.) and TQ group receiving only TQ (5 mg/kg b.w./day, p.o.). All treatments were applied for 5 weeks. Pb treatment induced oxidative stress status in testes as evidenced by a significant decrease in the antioxidant enzymes activities such as superoxide dismutase, glutathione peroxidase and catalase, and in the reduced glutathione content and in a significant increase in the level of malondialdehyde. Interestingly, TQ supplementation completely reversed these biochemical changes caused by Pb to the control values. In conclusion, our results suggest, for the first time, that TQ is very efficient in preventing Pb-induced testicular oxidative stress. This study will open new perspectives for the clinical use of TQ in Pb intoxication.

  20. Hypoxia Stress Test Reveals Exaggerated Cardiovascular Effects in Hypertensive Rats after Exposure to the Air Pollutant Acrolein

    EPA Science Inventory

    Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in susceptible populations with cardiovascular disease. Stress tests are useful in assessing cardiovascular risk and manifesting latent effects of exposure. The goal of this study w...