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Alian Aymen A - - 2011
OBJECTIVE: The photoplethysmographic (PPG) waveforms are modulated by the respiratory, cardiac and autonomic nervous system. Lower body negative pressure (LBNP) has been used as an experimental tool to simulate loss of central blood volume in humans. The aim of our research is to understanding PPG waveform changes during progressive hypovolemia. ...
Bátkai Sándor - - 2011
Hypertension is a complex, multifactorial disease, and its development is determined by a combination of genetic susceptibility and environmental factors. Several mechanisms have been implicated in the pathogenesis of hypertension: increased activity of the sympathetic nervous system, overactivation of the renin-angiotensin aldosterone system (RAAS), dysfunction of vascular endothelium, impaired platelet ...
Polglase Graeme R - - 2012
Cerebral blood flow disturbance is a major contributor to brain injury in the preterm infant. The initiation of ventilation may be a critical time for cerebral hemodynamic disturbance leading to brain injury in preterm infants, particularly if they are exposed to inflammation in utero. We aimed to determine whether exposure ...
Keith Stephen E - - 2011
Using a manikin, equivalent free-field sound pressure level measurements were made from the portable digital audio players of 219 subjects, aged 10 to 17 years (93 males) at their typical and "worst-case" volume levels. Measurements were made in different classrooms with background sound pressure levels between 40 and 52 dBA. ...
Hoshino Yuko - - 2011
To determine the mechanical upper airway properties and compensatory neuromuscular responses to obstruction during propofol anesthesia in the follicular and luteal phases of the menstrual cycle. Prospective, randomized study. University-affiliated hospital. 12 premenopausal female volunteers for studies of upper airway collapse throughout their menstrual cycle during the follicular phase (6 ...
Yasui Kyuichi - - 2011
The effect of static pressure on acoustic emissions including shock-wave emissions from cavitation bubbles in viscous liquids under ultrasound has been studied by numerical simulations in order to investigate the effect of static pressure on dispersion of nano-particles in liquids by ultrasound. The results of the numerical simulations for bubbles ...
Suissa Daniel - - 2011
Several randomized controlled trials comparing negative-pressure therapy to standard wound care for chronic wounds have been published. Although these studies suggest a benefit for negative-pressure therapy, the majority of the review articles on the topic conclude that the studies are inconclusive. The authors conducted a quantitative meta-analysis of the effectiveness ...
Koch P - - 2011
Bubble dynamics is investigated numerically with special emphasis on the static pressure and the positional stability of the bubble in a standing sound field. The bubble habitat, made up of not dissolving, positionally and spherically stable bubbles, is calculated in the parameter space of the bubble radius at rest and ...
Mitchell Gary F - - 2011
Aortic stiffness increases with age and vascular risk factor exposure and is associated with increased risk for structural and functional abnormalities in the brain. High ambient flow and low impedance are thought to sensitize the cerebral microcirculation to harmful effects of excessive pressure and flow pulsatility. However, haemodynamic mechanisms contributing ...
Kolipaka Arunark - - 2012
To demonstrate feasibility of using MR elastography (MRE) to identify hypertensive changes in the abdominal aorta when compared with normotensives based on the stiffness measurements. MRE was performed on eight volunteers (four normotensives and four hypertensives) to measure the effective stiffness of the abdominal aorta. MRE wave images are directionally ...
Tung Yao-Sheng YS Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, Mail Code 8904, 1210 Amsterdam Avenue, New York, New York 10027, - - 2011
The activation of bubbles by an acoustic field has been shown to temporarily open the blood-brain barrier (BBB), but the trigger cause responsible for the physiological effects involved in the process of BBB opening remains unknown. Here, the trigger cause (i.e., physical mechanism) of the focused ultrasound-induced BBB opening with ...
Bowman Thomas A - - 2011
OBJECTIVE: To test the hypothesis that an educational intervention would improve the resuscitator's ability to provide on-target volume ventilation during pulmonary compliance changes. STUDY DESIGN: Neonatal professionals (n = 27) ventilated an electromechanical lung model simulating a 3-kg baby while targeting a tidal volume of 4-6 mL/kg. In this preintervention ...
Stock C - - 2011
We report neutron scattering measurements of critical magnetic excitations in the weakly ferromagnetic superconductor UCoGe. The strong non-Landau damping of the excitations we observe, although unusual, has been found in another related ferromagnet, UGe_{2} at zero pressure. However, we also find that there is a significant anisotropy of the magnetic ...
Grignola Juan C - - 2011
To characterize hydraulic right ventricle (RV) afterload by pulmonary arterial pressure waveform analysis in an acute pulmonary hypertension (PH) model. Pulmonary artery (PA) flow and pressure were recorded in six anesthetized sheep. Acute isobaric PH was induced by phenylephrine (active) and PA mechanical constriction (passive). We estimated the amplitude of ...
Reymond Philippe - - 2012
Decrease in arterial compliance leads to an increased pulse pressure, as explained by the Windkessel effect. Pressure waveform is the sum of a forward running and a backward running or reflected pressure wave. When the arterial system stiffens, as a result of aging or disease, both the forward and reflected ...
Coutinho Thais T Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, - - 2012
Pulse pressure (an indirect measure of arterial stiffness) is a robust predictor of cardiovascular events, but its pathophysiology remains poorly understood. To gain insight into the pathophysiology of arterial stiffness we conducted an exploratory investigation of the associations of 47 circulating biomarkers in etiologic pathways of arteriosclerosis with brachial artery ...
Pereira Marcelo Pinto - - 2011
Proprioceptive neuromuscular facilitation (PNF) is an attractive method to increase strength and proprioception of elderly individuals. However, a major clinical concern about the prescription of PNF is the belief that it can cause a cardiovascular overload, because it involves close-to-maximal loads and isometric contractions. Yet the acute effect of a ...
Xiang Lusha - - 2012
We have shown that obese Zucker rats with orthopedic trauma (OZT) exhibit a loss of arteriolar tone in skeletal muscle. We hypothesize that the loss of arteriolar tone in OZT blunts vasoconstrictor responses to hemorrhage, resulting in an impaired blood pressure recovery. Orthopedic trauma was induced with soft tissue injury ...
Venturelli Massimo - - 2012
The exact role of arousal in central and peripheral hemodynamic responses to passive limb movement in humans is unclear but has been proposed as a potential contributor. Thus, we used a human model with no lower limb afferent feedback to determine the role of arousal on the hemodynamic response to ...
Miyashita Masashi - - 2011
Abstract In this study, we compared the effects of accumulated and continuous running on resting arterial blood pressure. Ten normotensive/pre-hypertensive men, aged 25.0 ± 4.2 years (mean ± s), participated in three 2-day trials at least one week apart in a randomized, repeated-measures design. On Day 1, participants rested (control) or ran at 70% ...
Deloach Stephanie S - - 2011
BackgroundThere is a high burden of premature cardiovascular disease (CVD) among African Americans. Measures of central aortic blood pressure (CASP) and wave reflection are predictive of CVD risk in adults, but there is a paucity of data regarding the relation of these measures to target organ damage among adolescents. The ...
Lazdam Merzaka M Department of Cardiovascular Medicine, University of Oxford, Oxford, - - 2012
A phenomenon of endothelial impairment, independent of classical cardiovascular risk factors, has been observed in young people. We identified subjects with persistently reduced, or declining, endothelial function during adolescence and early adulthood, without apparent cardiovascular risk, and investigated the clinical relevance of this finding. Endothelial vasomotor responses were assessed by ...
Ma Estella P-M - - 2012
Vocal attack time (VAT) is the time lag between the growth of the sound pressure signal and the development of physical contact of vocal folds at vocal initiation. It can be derived by a cross-correlation of short-time amplitude changes occurring in the sound pressure and electroglottographic (EGG) signals. Cantonese is ...
Steele Catriona - - 2012
It was hypothesized that tongue-palate pressure generation might directly facilitate hyoid movement in swallowing through the anatomical connections of the extrinsic tongue muscles. If true, non-invasive measures of tongue-palate pressure timing might serve as a proxy measure of hyoid excursion. The timing relationships between events in the tongue-palate pressure and ...
Hashimoto Junichiro - - 2011
A significant link has been reported between aortic stiffening and renal microvascular damage, but the underlying mechanism remains poorly understood. We hypothesized that alterations in central and renal hemodynamics are responsible for this link. In 133 patients with hypertension, pressure waveforms were recorded on the radial, carotid, femoral, and dorsalis ...
Scalzo Fabien - - 2012
The waveform morphology of intracranial pressure (ICP) pulses holds essential informations about intracranial and cerebrovascular pathophysiological variations. Most of current ICP pulse analysis frameworks process each pulse independently and therefore do not exploit the temporal dependency existing between successive pulses. We propose a probabilistic framework that exploits this temporal dependency ...
Dave Jaydev - - 2011
The purpose of this study was to develop and validate a noninvasive pressure estimation technique based on subharmonic emissions from a commercially available ultrasound contrast agent and scanner, unlike other studies that have either adopted a single-element transducer approach and/ or use of in-house contrast agents. Ambient pressures were varied ...
Raamat Rein - - 2011
To study factors affecting the accuracy of oscillometric measurement. By means of a computer-based simulator, a variety of arterial pressure pulses of different shapes and amplitudes were composed as an input signal of the model, whereas cuff volume oscillations were obtained as an output signal. The shape of the artery-cuff ...
Chung Ki-Young - - 2011
This study was designed to evaluate the effect of microgravity on the diurnal variation of intraocular pressure (IOP). IOPs were measured with the pressure phosphene tonometer in 1 subject (the first Korean astronaut) during spaceflight. IOPs were measured every 3 hours during day time (6 times per day) at 2 ...
Schurtenberger E - - 2011
We report on design and performance of an extended surface forces apparatus (eSFA) built into a pressurized system. The aim of this instrument is to provide control over static pressure and temperature to facilitate direct surface force experiments in equilibrium with fluids at different loci of their phase diagram. We ...
Maxwell Adam D - - 2011
Histotripsy is a therapy that focuses short-duration, high-amplitude pulses of ultrasound to incite a localized cavitation cloud that mechanically breaks down tissue. To investigate the mechanism of cloud formation, high-speed photography was used to observe clouds generated during single histotripsy pulses. Pulses of 5-20 cycles duration were applied to a ...
Mackeith S - - 2011
Despite the popularity of Rapid Rhino packs, there are no clear guidelines regarding the volume of air to be inflated when used in the management of epistaxis. The manufacturers suggest that subjective assessment by pilot cuff palpation is used to guide inflation. However, studies have clearly demonstrated that clinicians are ...
Hodgkinson James J Department of Primary Care Clinical Sciences, University of - - 2011
Ambulatory blood pressure monitoring (ABPM) is more accurate than clinic and home monitoring in diagnosing hypertension. A diagnostic strategy for hypertension using ABPM following an initial raised clinic reading would reduce misdiagnosis and NHS costs. If the first and second measurements taken during a consultation are both > or = ...
Ahn Chi Bum - - 2011
Blood viscosity during operation of ventricular assist device (VAD) can be changed by various conditions such as anemia. It is known generally that the blood viscosity can affect vascular resistance and lead to change of blood flow. In this study, the effect of fluid viscosity variation on hemodynamic energy was ...
Zhang Guanqun - - 2011
Pulse transit time (PTT) is a proven, simple to measure, marker of blood pressure (BP) that could potentially permit continuous, noninvasive, and cuff-less BP monitoring (after an initial calibration). However, pulse arrival time (PAT), which is equal to the sum of PTT and the pre-ejection period, is gaining popularity for ...
Harakeh Zeena - - 2011
BACKGROUND: Peers influence adolescent and young adult smoking, but little is known about the underlying mechanisms. It is necessary to understand whether the current assumption of peer pressure is valid, or whether an alternative explanation as imitation is more appropriate. We examined whether passive (imitation) and/or active (pressure) peer influence ...
Fowlie Jennifer - - 2011
OBJECTIVE: To evaluate the magnitude and distribution of joint contact pressure on the medial tibial condyle after grade III cranial horn tears of the medial meniscus. STUDY DESIGN: Experimental study. ANIMALS: Cadaveric equine stifles (n = 6). METHODS: Cadaveric stifles were mounted in a materials testing system and electronic pressure ...
Clement Katherine C - - 2011
PURPOSE: Neurally adjusted ventilatory assist (NAVA) is a mode of ventilation designed to improve patient-ventilator interaction by interpreting a neural signal from the diaphragm to trigger a supported breath. We hypothesized that neurally triggered breaths would reduce trigger delay, ventilator response times, and work of breathing in pediatric patients with ...
Turhan Tuncer - - 2011
INTRODUCTION: The most important limitations to endoscopic procedures in the ventricular system of the brain are due to the constraint of working inside a fluid. The evacuation of cerebrospinal fluid (CSF) from the ventricles is performed often in microsurgical interventions using a surgical microscope. This study aimed at studying the ...
Matsui Yoshio - - 2011
OBJECTIVES: To clarify the implications of the home arterial stiffness index (HASI), we compared HASI with other arterial stiffness measures and investigated the association between HASI and hypertensive target organ damage (TOD). METHODS: We assessed brachial-ankle pulse wave velocity (baPWV) and the carotid augmentation index (cAIx) as measures of arterial ...
Paraguassu W - - 2011
RbNd(WO(4))(2) was investigated by high pressure Raman spectroscopy in the 0.1-12.3 GPa pressure interval. The assignment of modes was made based on lattice dynamics calculations and the results of these calculations helped us to also discuss the high pressure behavior of phonon spectra in this material. Our results show that a ...
Faez Telli - - 2011
In this paper, the influence of a dynamic variation in the ambient pressure on the subharmonic response of phospholipid-coated microbubbles was investigated. The ambient pressure in water was modulated by a 2.5 kHz acoustic wave with a peak amplitude of 15 kPa. We investigated the fundamental and subharmonic emissions at ...
Takeyama Masaharu - - 2011
OBJECTIVE: The pleth variability index (PVI), which is calculated from respiratory variations in the perfusion index (PI), reportedly predicts fluid responsiveness. However, vasomotor tone fluctuations induced by nociceptive stimuli change the PI and may reduce the accuracy of PVI. The aim of this study was to confirm the effects of ...
Hawkins Richard N - - 2011
Abstract The aim of the present study was to determine whether changing stance width would result in a corresponding change in postural and/or pistol stability. Twelve national-standard male air pistol shooters performed 10 shots each at five stance widths (30?cm, 45?cm, 60?cm, 75?cm, and 90?cm). Postural stability was determined by ...
Sun Dan Dan - - 2011
We aimed to establish a canine model of acute thromboembolic pulmonary hypertension (ATEPH) and to explore the feasibility of diagnosing pulmonary hypertension (PH) through the Doppler flow spectra of the superior vena cava (SVC). A canine model of ATEPH was developed by infusing thrombus into the right femoral vein. The ...
Kim Eun Ran - - 2011
Background and Aim: DA 9701, a novel prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber, has strong prokinetic effects and enhances gastric compliance in conscious dogs. In this study, the effects of DA 9701 on gastric accommodation were studied in conscious dogs. Methods: Beagle dogs with an implanted gastric ...
Richter Hans Peter - - 2011
OBJECTIVE: Acute right ventricular failure (RVF) is a life-threatening condition. This study investigated whether the combination of central venous pressure (CVP) and left ventricular functional preload parameters, such as stroke volume variation (SVV) and pulse pressure variation (PPV), can be used for the detection of acute RVF and for guidance ...
Lee Jong-Hwan - - 2011
OBJECTIVE: The aim of this study was to evaluate the ability of pulse-pressure variation to predict fluid responsiveness during heart displacement for off-pump coronary artery bypass surgery using receiver operating characteristic analysis. DESIGN: A prospective study. SETTING: A clinical study in a single cardiac anesthesia institution. PARTICIPANTS: Thirty-five patients undergoing ...
Han Hui - - 2011
High pressure measurements in most scientific fields rely on metal vessels given the superior tensile strength of metals. We introduce high pressure magnetic resonance imaging (MRI) measurements with metallic vessels. The developed MRI compatible metallic pressure vessel concept is very general in application. Macroscopic physical systems are now amenable to ...
Foster Gary P - - 2011
Ischemic pre-condition of an extremity (IPC) induces effects on local and remote tissues that are protective against ischemic injury. To test the effects of IPC on the normal hypoxic increase in pulmonary pressures and exercise performance, 8 amateur cyclists were evaluated under normoxia and hypoxia (13% F(I)O(2)) in a randomized ...
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