We present broadband transient absorption spectroscopy on the fluorescent copolymer poly(9,9-dioctylfluorene-co-benzothiadiazole) under hydrostatic pressure of up to 75 kbar. We observe a strong reduction of the stimulated emission intensity under pressure, coupled with slower decay kinetics and reduced fluorescence intensity. These observations indicate increased delocalization of photogenerated singlet excitons, facilitated by ...

Increased vascular production of reactive oxygen species (ROS; termed oxidative stress) has been implicated in various chronic diseases, including hypertension. Oxidative stress is both a cause and a consequence of hypertension. Although oxidative injury may not be the sole etiology, it amplifies blood pressure elevation in the presence of other ...

The effect of compressive stress on the electrochemical behavior of flexible supercapacitors assembled with single-walled carbon nanotube (SWNT) film electrodes and 1 M aqueous electrolytes with different anions and cations were thoroughly investigated. The under-pressed capacitive and resistive features of the supercapacitors were studied by means of cyclic voltammetry measurements ...

The present study quantitatively explored the effects of mothers' perceived time pressure, as well as meal-related variables including mothers' convenience orientation and meal preparation confidence, on the healthiness of evening meals served to school-aged children (5-18 years old) over a 7-day period. A sample of 120 employed mothers, who identified ...

Aims:  When assessing sympathetic activation in acute stress, the attention is often limited to the sympatho-neural axis, whereas sympatho-adrenal activation, that can only be detected with poor time resolution from the concentration of plasma catecholamines, is often neglected. This study is aimed at reinvestigating the role and the relevance of ...

Excessive wall circumferential stress in arteries caused by luminal pressure leads to endothelial damage and clinical consequences. In addition to circumferential stress, arterial wall contains residual stress with compressive and tensile components on intima and adventitia sides. The intimal compressive component compensates part of tensile stress induced by blood pressure, ...

To examine the association between two job stress models-the job strain (JDC) and the effort-reward imbalance (ERI) model-and ambulatory blood pressure monitoring in call handler operators. Participants included 74 women (age, 34.9 ± 9.9 years) and 26 men (age 36.0 ± 10.8 years) who were monitored on 2 workdays for ambulatory blood pressure. Measures of ...

A new data collection protocol for forced oscillation experiments using a multianvil high pressure device is reported. We derive the stress of the sample at high pressure and temperature from synchrotron x-ray diffraction that is synchronized with sample strain measurements from x-ray radiographs. This method yields stress directly from the ...

The mechanisms by which heat stress impairs the control of blood pressure leading to compromised orthostatic tolerance are not thoroughly understood. A possible mechanism may be an attenuated blood pressure response to a given increase in sympathetic activity. This study tested the hypothesis that whole body heating attenuates the blood ...

We examined biventricular function during passive heat stress in endurance trained (ET) and untrained (UT) men to evaluate whether aerobic fitness alters the volumetric response. Body temperature was elevated ~0.8°C above baseline in 20 healthy men (10 ET, 64.4 ± 3.0 ml·kg(-1)·min(-1); and 10 UT, 46.3 ± 6.2 ml·kg(-1)·min(-1)) by ...

We showed that luminal flow stimulates nitric oxide (NO) production in thick ascending limbs. Ion delivery, stretch, pressure, and shear stress all increase when flow is enhanced. We hypothesized that shear stress stimulates NO in thick ascending limbs, whereas stretch, pressure, and ion delivery do not. We measured NO in ...

The aim of this study was to evaluate the effect of needle-insertion depth on the irrigant flow inside a prepared root canal during final irrigation with a syringe and two different needle types using a Computational Fluid Dynamics (CFD) model. A validated CFD model was used to simulate irrigant flow ...

This study examined the role of pro-victim attitudes, personal responsibility, coping responses to observations of bullying, and perceived peer normative pressure in explaining defending the victim and passive bystanding behavior in bullying. A total of 462 Italian early adolescents (mean age = 13.4 years, SD = 9 months) participated in ...

The impact of haemodynamic stress on left ventricular (LV) dyssynchrony in heart failure with normal ejection fraction (HFNEF) remains unknown. We sought to evaluate the relationship and predictive value of dynamic changes of LV dyssynchrony on hypertensive HFNEF. A total of 131 subjects including 47 hypertensive HFNEF patients, 34 hypertensive ...

To evaluate the effect of root canal taper on irrigant flow inside a prepared root canal during final irrigation with a syringe and two types of needles, using a Computational Fluid Dynamics (CFD) model. A validated CFD model was used to simulate irrigant flow from either a side-vented or a ...

S. Rice and D. Keller (2009) previously reported that participants who were put under time pressure tended to comply more with a diagnostic aid than participants who were not put under time pressure. The present study investigates whether or not learning the benefits of this time pressure heuristic carries over ...

OBJECTIVE: This research examined the impact of perceived discrimination on ambulatory blood pressure (ABP) and daily level affect during social interaction. DESIGN: For 24 hrs, adult Black and White participants wore an ABP monitor and completed palm pilot diary entries about their social interactions. MAIN OUTCOME MEASURES: Mean level and ...

Among the psychosocial factors that may influence the development, maintenance, and progression of cardiovascular disease, defensive hostility as a possible risk factor has received substantial empirical support in recent years. The aim of our study was to analyze the relationship between defensive hostility and cardiovascular response to stress situations, as ...

Academic examination stress is reported to increase physiological and self-report measures of stress and to decrease immune functioning. Here, we investigate biochemical and self-report measures of stress, immune functioning, and academic pressures before and during a midterm examination period. Undergraduate students were asked to complete a measure of global stress, ...

The problem of hypertension among African-Americans is one of the major areas of health disparities. The American Heart Association (2009) noted that the prevalence of hypertension among African-Americans is perhaps among the highest in the world and this is particularly so among African-American women (44.0%). The purpose of this study ...

The study aimed to: confirm that acute stress elicits metabolically exaggerated increases in cardiac activity; test whether individuals with elevated resting blood pressure show more exaggerated cardiac reactions to stress than those who are clearly normotensive; and explore the underlying mechanisms. Cardiovascular activity and oxygen consumption were measured pre-, during, ...

Cardiovascular reactivity to stress is most commonly studied in the laboratory. Laboratory stressors may have limited ecological validity due to the many constraints, operating in controlled environments. This paper will focus on paradigms that involve the measurement of cardiovascular reactions to stress in real life using ambulatory monitors. Probably the ...

Motivated by recent clinical and laboratory findings of important effects of pulsatile pressure and flow on arterial adaptations, we employ and extend an established constrained mixture framework of growth (change in mass) and remodelling (change in structure) to include such dynamical effects. New descriptors of cell and tissue behavior (constitutive ...

Regadenoson is a pharmacologic stress agent, which was recently approved for stress myocardial perfusion imaging (MPI). Aside from the initial protocol-driven studies, clinical experience with this stress agent is limited. Furthermore, low-level treadmill testing in a large population with regadenoson has not previously been evaluated. We describe our experience in ...

OBJECTIVE: To test the hypothesis that potential sites of weakness within normal nasal arteries, when stressed, contribute to the mechanism of epistaxis, we 'stress-tested' nasal arteries in unfixed cadaveric heads, using pressure injection of feeding arteries. MATERIALS AND METHODS: Indian ink with latex was injected into maxillary arteries under high ...

To investigate the relation between forgiveness and apology as they relate to cardiovascular reactivity and recovery, 29 men and 50 women were exposed to an interpersonal transgression (i.e., verbal harassment) while performing a serial subtraction task. Participants were categorized into high and low forgiveness groups based on scores on the ...

The midfacial skeleton in the human lineage demonstrates a wide spectrum of variation that may be the consequence of different environmental and mechanical selective pressures. However, different facial configurations may develop under comparable selective regimes. For example, the Neanderthal high and projected face and the Inuit broad and flat face ...

The Valsalva maneuver can be used as a noninvasive index of autonomic control of blood pressure and heart rate. The purpose of this investigation was to test the hypothesis that sympathetic mediated vasoconstriction, as referenced by hemodynamic responses during late phase II (phase IIb) of the Valsalva maneuver, is inhibited ...

Oxidative stress has been shown to play an important role in the development of hypertensive renal injury. Peroxisome proliferator-activated receptors alpha (PPARalpha) has antioxidant effect. In this study, we demonstrated that fenofibrate significantly reduced proteinuria, inflammatory cell recruitment and extracellular matrix (ECM) proteins deposition in the kidney of SHRs without ...

The purpose of the present study was to examine whether stress-somatic symptom associations may be more pronounced among individuals whose bodies exhibit higher levels of cardiovascular reactivity to a laboratory social stress task. During an initial laboratory session, participants delivered a 5-min speech and individual differences in cardiovascular reactivity were ...

Perceived discrimination has been linked to poor health outcomes among ethnic and racial minorities in the United States, though the relationship of discrimination-related stress to immigrant health is not well understood. This article reports findings from a preliminary study that examined blood pressure and Epstein-Barr virus antibody levels in relation ...

Although researchers have experimentally examined the mechanisms underlying pressure-induced forms of suboptimal performance, or "choking under pressure," there is a lack of research exploring the personal experience of this phenomenon. In an attempt to fill this void in the literature, this study explored experienced golfers' perceptions of the choking experience ...

This study was aimed at determining whether there are differences in emotional personality traits and psychosocial stress between hypertension and normotension. From a large community sample of adults, 14 individuals having hypertension and showing clinic blood pressures (BP) >or=140/90 mm Hg and self-measured BPs >or=135/85 mm Hg (sustained hypertensives) were ...

OBJECTIVE: To identify risk indicators for high stress and low mental energy as well as to describe psychosocial working conditions at different types of call centres. Participants: 1183 operators from 28 call centres in Sweden, both external and internal, with different levels of task complexity, ownership and geographical location. METHOD: ...

Background. A necktie may elevate intracranial pressure through compression of venous return. We hypothesised that a tight necktie would deleteriously alter cerebrovascular reactivity. Materials and Methods. A necktie was simulated using bespoke apparatus comprising pneumatic inner-tube with aneroid pressure-gauge. Using a randomised crossover design, cerebrovascular reactivity was measured with the ...

To examine the interactive influence of urbanicity on cardiovascular reactivity to speech stressors among 103 urban and 93 rural Cameroonians. Heart rate, systolic, and diastolic blood pressure (HR, SBP, and DBP) changes from baseline were assessed during a speech preparation period, speech stressor task, and post-speech recovery period. After adjusting ...

Repeated exposure to stress may favor, both in experimental animals and in humans, an increase in blood pressure, leading in some instances to a true hypertensive state. It is thought that stress-induced hypertension is mediated by sympathetic nervous system activation that in turn, by exerting vasoconstrictor effects and increasing heart ...

BACKGROUND: Exaggerated cardiovascular reactivity to stressful stimuli may be a risk factor for the development of hypertension. The genetic influence on blood pressure (BP) reactivity to stress and its control mechanisms has been receiving considerable support. This study aims at examining the heritability of BP and its intermediate hemodynamic phenotypes ...

Cardiovascular (CV) hyperreactivity to stress must be reasonably stable if it is considered to be important in the development of hypertension and CV disease. The aim of the present study was to assess long-term stability of blood pressure, heart rate, epinephrine, and norepinephrine responses to a cold pressor test and ...

Cardiovascular responses to single stressors diminish over time. Interaction of different stressors influencing hemodynamic variables, indicative of stress-induced reactivity and physiological responses are, however, poorly understood. We investigated time course of mental (using mental arithmetic, MA) and orthostatic (using head up tilt, HUT) challenges induced responses in 16 males. Three ...

As compared to negative affect, only a small number of studies have examined influences of positive affect on cardiovascular stress responses, of which only a few were concerned with cardiovascular recovery. In this study, heart rate, low- and high-frequency heart rate variability, blood pressure, and levels of subjectively experienced stress ...

OBJECTIVES: This study assessed cardiovascular reactivity to mental stress and cold pressure test in migraineurs and controls. It compared the cardiovascular reactivity between patients with migraine with aura and patients with migraine without aura. BACKGROUND: Several studies have assessed the autonomic nervous system functioning and cardiovascular responses to stressor stimuli ...

The NaCl-to-Cmcm phase transition and the Cmcm structure of InAs under high pressure are studied by x-ray diffraction. The lattice parameters and fractional coordinates are given as a function of pressure. We propose a mechanism responsible for this type of symmetry breaking under pressure. We show that the ppσ interactions ...

Monoamine oxidases (MAOs) are mitochondrial enzymes that catabolize prohypertrophic neurotransmitters, such as norepinephrine and serotonin, generating hydrogen peroxide. Because excess reactive oxygen species and catecholamines are major contributors to the pathophysiology of congestive heart failure, MAOs could play an important role in this process. Here, we investigated the role of ...

The inferred cost of work-related stress call for early prevention strategies. In this, we see a new opportunity for affective and pervasive computing by detecting early warning signs. This paper goes one step toward this goal. A collective of 33 subjects underwent a laboratory stress intervention, while a set of ...

Different studies regarding the role of norms on the expression of prejudice have shown that the anti-prejudice norm influences people to inhibit prejudice expressions. However, if norm pressure has led to a substantial decrease in the public expression of prejudice against certain targets (e.g., blacks, women, blind people), little theoretical ...

The stress distribution in the vessel wall has important bearing on vascular function including intima, media, and adventitia. The residual strain in the vessel wall has been thought to largely normalize the transmural stress distribution with slightly higher values at the intima. In hypertension, the compensatory increase in opening angle ...

OBJECTIVE: The study of anger suppression and risk for cardiovascular disease has relied predominately on inspection of correlations between trait anger-in and cardiovascular risk factors and disease. This approach tells us little about whether inhibitory processes have anything to do with outcomes, and cannot speak to whether suppression of anger ...

The venoarteriolar response (VAR) increases vascular resistance upon increases in venous transmural pressure in cutaneous, subcutaneous, and muscle vascular beds. During orthostasis, it has been proposed that up to 45% of the increase in systemic vascular tone is due to VAR-related local mechanism(s). The objective of this project was to ...

Oxidative stress produced through reactive oxygen species (ROS) enhancement is considered to play a key role in the development and maintenance of hypertension. In the vasculature, the most important source of ROS is the reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase enzyme. The principal stimulus of this enzyme is angiotensin ...