We hypothesized that attachment of elastic coil to the left ventricular (LV) wall, capable of exerting outward forces may allow the transfer of energy from systole to diastole and improve diastolic function. Methods and results: An extra-ventricular-device, composed of a series of elastic elements interposed between spiral screws attached to ...

This paper presents a new approach to the estimation of unknown central aortic blood pressure waveform from a directly measured peripheral blood pressure waveform, in which a physics-based model is employed to solve for a subject- and state-specific Individualized Transfer Function (ITF). The ITF provides the means to estimate the ...

We investigate the pressure effect on the layered Dirac fermion system, which is realized in quasi-two-dimensional organic compound α-(BEDT-TTF)(2)I(3). The trajectory of the contact points is investigated using the tight-binding model with the transfer integrals determined by x-ray diffraction experiments. Vanishing of the Dirac fermion spectrum, opening of the gap, ...

We examined changes in cerebral circulation in 15 healthy men during exposure to mild +Gz hypergravity (1.5 Gz, head-to-foot) using a short-arm centrifuge. Continuous arterial pressure waveform (tonometry), cerebral blood flow (CBF) velocity in the middle cerebral artery (transcranial Doppler ultrasonography), and partial pressure of end-tidal carbon dioxide (ETCO(2)) were ...

The prognostic value of central systolic blood pressure has been established recently. At present, its noninvasive assessment is limited by the need of dedicated equipment and trained operators. Moreover, ambulatory and home blood pressure monitoring of central pressures are not feasible. An algorithm enabling conventional automated oscillometric blood pressure monitors ...

BackgroundThe accuracy of the central aortic systolic (SBP-C) and pulse (PP-C) blood pressures estimated noninvasively by a generalized transfer function technique has been questioned. The purpose of the present study was to quantify precisely the impact of the input errors (differences between the oscillometric (SBP-O, DBP-O, PP-O) and invasive (SBP-B, ...

We report on the development of a novel atmospheric pressure photoionization setup and its applicability for in situ degradation product studies of atmospherically relevant compounds. A custom miniature spark discharge lamp was embedded into an ion transfer capillary, which separates the atmospheric pressure from the low pressure region in the ...

Exfoliated graphene and few layer graphene samples supported on SiO2 have been studied by Raman spectroscopy at high pressure. For samples immersed on a alcohol mixture, an electron transfer of dn/dP~8 x10^12 cm-2 GPa-1 is observed for monolayer and bilayer graphene, leading to giant doping values of n~6 x10^13 cm-2 ...

BACKGROUND: CD4CD25Foxp3 regulatory T cells (Tregs) are potent inhibitors of inflammation and autoimmune diseases. Because inflammation has been associated with development of cardiac fibrosis in experimental hypertension, here we investigated whether adoptively transferred Tregs would inhibit development of cardiac fibrosis initiated by elevating blood pressure. METHODS: Cardiac fibrosis was induced ...

OBJECTIVE: To study fluid dynamics during ET. DESIGN: Computational fluid dynamics were applied to calculate fluid velocity changes, dynamic pressure differences, and shear stress in the transferred load for the following injection speeds: 0.1, 1, 6, 12, and 20 m/sec. SETTING: Academic research institute of mechanical engineering and reproduction biotechnology ...

Distal tibia coronal plane malalignment predisposes the ankle joint to asymmetric load. The purpose of this cadaveric study was to quantify changes in pressure and force transfer in an ankle with a supramalleolar deformity. Seventeen cadaveric lower legs were loaded with 700 N after creating supramalleolar varus and valgus deformities. ...

Recently it was shown that distortion product otoacoustic emissions (DPOAEs) can be measured as vibration of the human tympanic membrane in vivo, and proposed to use these vibration DPOAEs to support a differential diagnosis of middle-ear and cochlear pathologies. Here, we investigate how the reverse transfer function (r-TF), defined as the ...

Measurement of the Ce valence in the heavy fermion CeCu_{2}Si_{2} is reported for the first time under pressure and at low temperature (T=14  K) in proximity of the superconducting region. CeCu_{2}Si_{2} is considered as a strong candidate for a new type of pairing mechanism related to critical valence fluctuations which could ...

Acute psychological stress challenges the cardiovascular system with an increase in BP (blood pressure), HR (heart rate) and reduced BRS (baroreflex sensitivity). β-adrenergic blockade enhances BRS during rest, but its effect on BRS during acute psychological stress is unknown. This study tested the hypothesis that BRS is higher during acute ...

1. The amygdala is a part of the limbic system that is associated with mediating the emotional and hormonal response to stress and although studies have focused on the central amygdala, there is increasing evidence that the medial amygdala is a major region activated by stressful stimuli. 2. Neuroanatomical studies ...

Having intensive care patients sit out of bed improves their respiration and psyche and reduces complications of immobilization. To compare seating interface pressures to determine a preferred seating surface for patients sitting out of bed. The study was conducted in 2 phases among intensive care patients with impaired mobility who ...

Objectives: To test for differences in stress-induced cardiovascular functioning among hypertensive and normotensive African American (AA) smokers. Methods: Participants (n = 35) were exposed to both stress and neutral mood inductions. Results: Repeated measures analyses of covariance produced a significant group x mood condition interaction for systolic blood pressure (P ...

A diet enriched in lupin kernel flour can lower blood pressure, but mechanisms responsible are unclear. Lupin is a source of polyphenols, protein, and L-arginine, factors that may influence blood pressure via effects on oxidative stress and vascular function. Therefore, we aimed to determine the effects of a lupin-enriched diet ...

To study potential ecological impacts of CO(2) leakage to shallow groundwater and soil/sediments from geologic CO(2) sequestration (GCS) sites, this work investigated the viability and metal reduction of Shewanella oneidensis MR-1 under CO(2) stress. While MR-1 could grow under high-pressure nitrogen gas (500 psi), the mix of 1% CO(2) with ...

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 ...

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 ...

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 ...

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 ...

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 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 ...

This qualitative research investigates the role religion plays in relation to blood pressure control among a Southern California Thai population with hypertension. A total of 15 Thai individuals between the ages of 45-95 were interviewed. All participants indicated that stress plays a significant role in determining their ability to manage ...

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 ...