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Results 401 - 450 of 2479
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Westenberg Jos J M - - 2012
The Bramwell-Hill model describes the relation between vascular wall stiffness expressed in aortic distensibility and the pulse wave velocity (PWV), which is the propagation speed of the systolic pressure wave through the aorta. The main objective of this study was to test the validity of this model locally in the ...
Ilesanmi Olayinka Stephen - - 2012
The health systems designed to cater for patients with chronic illnesses like hypertension have not fully evaluated the burden of long term therapy and its effect on patient outcome. This study assessed the financial implication and cost effectiveness of hypertension treatment in a rural Nigerian town. A chart review of ...
Clays Els - - 2012
While moderate and vigorous leisure time physical activities are well documented to decrease the risk for cardiovascular disease, several studies have demonstrated an increased risk for cardiovascular disease in workers with high occupational activity. Research on the underlying causes to the contrasting effects of occupational and leisure time physical activity ...
Prakash Smita S Department of Anaesthesia and Intensive Care, Vardhman Mahavir Medical College and Safdarjang Hospital, New Delhi, - - 2012
Baroreflex failure results in wide excursions of blood pressure and heart rate. We report two cases that developed severe postoperative hypertension after radical neck dissection. Carotid sinus denervation during neck dissection may be the cause of the reflex hypertension once general anesthesia-induced vasodilatation has ended.
Czosnyka Marek M Academic Neurosurgical Unit, Addenbrooke's Hospital, Cambridge, UK. - - 2012
The cerebrovascular time constant (τ) describes the time to establish a change in cerebral blood volume after a step transient in arterial blood pressure (ABP). We studied the relationship between τ, ABP, intracranial pressure (ICP), and end-tidal carbon dioxide concentration (EtCO2). Recordings from 46 anaesthetized, paralysed and ventilated New Zealand ...
Fourchet François - - 2011
This study aimed to compare foot plantar pressure distribution while jogging and running in highly trained adolescent runners. Eleven participants performed two constant-velocity running trials either at jogging (11.2±0.9km/h) or running (17.8±1.4km/h) pace on a treadmill. Contact area (CA in cm(2)), maximum force (F(max) in N), peak pressure (PP in ...
Bode Aron S - - 2011
BACKGROUND: Despite routine ultrasound mapping of upper extremity arteries and veins, early thrombosis and nonmaturation remain frequent complications following vascular access (VA) surgery. Besides vascular diameters, brachial artery stiffness is assumed to play an important role; however, reproducibility of measurements has never been established. The purpose of this study was ...
Hermeling Evelien - - 2011
BACKGROUND:: The current standard for arterial stiffness assessment, aortic pulse wave velocity (aPWV), is measured at diastolic pressure. Arterial stiffness, however, is pressure dependent. At the carotid artery level, the degree of this dependency can be quantified as the difference (ΔPWV) between systolic and diastolic (cPWVd) carotid pulse wave velocity. ...
Todd Alwyn S - - 2011
Background:  Studies of dietary sodium on vascular function and blood pressure (BP) in normotensive volunteers have shown conflicting results. There is very limited data available on the effect of chronic sodium loading from a low-sodium diet to a high-sodium diet on vascular function and BP in normotensive volunteers. Objective:  To ...
Girshberg Y - - 2012
Pressure has a profound effect on the paraelectric and ferroelectric properties of perovskite crystals. In this paper we theoretically investigate the effect of pressure on the cubic-to-tetragonal phase transition and on the soft mode dynamics of some classical perovskite crystals: BaTiO(3), PbTiO(3), and KNbO(3). We use a model consisting of ...
Mahjoub Y - - 2011
BACKGROUND: /st>In the intensive care unit, intra-abdominal hypertension (IAH) is a frequently encountered, life-threatening condition. The aim of this animal study was to evaluate the effect of IAH on left ventricular (LV) relaxation (i.e. the active phase of diastole). METHODS: /st>Seven male rabbits were anaesthetized before mechanical ventilation. A 20 ...
Merabet Nassiba - - 2011
The study addressed the hypothesis that soluble epoxide hydrolase (sEH) inhibition, which increases cardiovascular protective epoxyeicosatrienoic acids (EETs), exerts beneficial effects in an established chronic heart failure (CHF) model. In CHF rats, left ventricular (LV) function, perfusion and remodeling were assessed using MRI and invasive hemodynamics after 42-day (starting 8days ...
Yiou E - - 2011
During leg flexion from erect posture, postural stability along the medio-lateral direction is organized in advance during "anticipatory postural adjustments" (APAs). This study aimed to investigate the influence of temporal pressure on this anticipatory postural control of medio-lateral stability. Eight young healthy participants performed series of leg flexions (1) as ...
Hsiu Hsin - - 2011
Abstract Background: Cold stimulation (CS) accompanied by vasoconstriction can increase the stiffness of the arterial system. The vascular responses during CS have been studied using photoplethysmography (PPG), but most have focused on time-domain waveform indexes. Focusing on the radial arterial blood pressure (BPW) and the finger PPG waveforms, we aimed ...
Corazza Ivan - - 2011
The aim of this paper is to clarify some physical-mechanical aspects involved in the carbon dioxide angiography procedure (CO(2) angiography), with a particular attention to a possible damage of the vascular wall. CO(2) angiography is widely used on patients with iodine intolerance. The injection of a gaseous element, in most ...
Sutrakar Vijay Kumar - - 2011
Atomistic simulation of initial ⟨100⟩ oriented FCC Cu nanowires shows a novel coupled temperature-pressure dependent reorientation from ⟨100⟩ to ⟨110⟩ phase. A temperature-pressure-induced solid-solid ⟨100⟩ to ⟨110⟩ reorientation diagram is generated for Cu nanowire with varying cross-sectional sizes. A critical pressure is reported for Cu nanowires with varying cross-sectional sizes, ...
Saranathan Archana - - 2012
The study was performed to characterize the influence of tibial tuberosity realignment on the pressure applied to cartilage on the patella in the intact condition and with lesions on the lateral and medial facets. Ten knees were loaded in vitro through the quadriceps (586 N) and hamstrings (200 N) at ...
Feng Bibo - - 2012
A device is presented for efficiently enriching parahydrogen by pulsed injection of ambient hydrogen gas. Hydrogen input to the generator is pulsed at high pressure to a catalyst chamber making thermal contact with the cold head of a closed-cycle cryocooler maintained between 15 and 20K. The system enables fast production ...
Bhagat Anumeha - - 2011
Pulse examination by palpation of a peripheral artery against a bony prominence is the most commonly used and widely accepted method. However this is subjective and thus prone to errors. Although pulse waveform was recorded in the 19th century, it did not gain popularity because of inconvenience in using the ...
Bamberger Philip David - - 2011
The cerebral metabolic and vascular effects of intravenous norepinephrine have been shown in an animal model using somatosensory-evoked potentials (SSEPs). A case of intravenous norepinephrine resulting in a decrease in SSEP amplitude (of greater than 50%) despite no significant change in blood pressure, prior to cross-clamping during a carotid endarterectomy ...
Anile Carmelo - - 2011
The analysis of cerebrospinal fluid (CSF) pulse pressure waveform has been considered as a reliable method to investigate the intracranial system (ICS) dynamics. We have examined the morphological changes of the CSF pulse wave and of the sagittal sinus pressure (SSP) wave during a progressive increase in intracranial pressure (ICP) ...
Hughson R L - - 2012
Early evidence from long-duration flights indicates general cardiovascular deconditioning, including reduced arterial baroreflex gain. The current study investigated the spontaneous baroreflex and markers of cardiovascular control in six male astronauts living for 2-6 mo on the International Space Station. Measurements were made from the finger arterial pressure waves during spontaneous ...
Tanaka Yoshifumi Y Faculty of Economics, Tezukayama University, 7-1-1 Tezukayama, Nara 631-8501, Japan. - - 2011
The primary purpose of the present study was to examine kinematic characteristics and force control during a golf-putting task under a pressure condition. The secondary purpose was to provide an exploratory investigation of the relationship between changes in behavior (kinematics and force control) and performance on the one hand, and ...
Heffernan Kevin S - - 2011
Subacute and chronic cardiac adaptations to marathon running may increase risk for sudden death. Herein, it is proposed that cardiac arrhythmogenic remodeling resulting from prolonged strenuous exertion may also have a systemic vascular component. Marathon running reduces coronary pulse pressure and causes acute endothelial damage, possibly via altering concentrations of ...
Sariali Elhadi - - 2011
A finite elements model was developed in order to evaluate the combined influence of the head lateral microseparation and the cup abduction angle on the contact pressure in Ceramic-on-Ceramic Total Hip Arthroplasty. The model's parameters were those used on the Leeds II hip simulator. A 32mm head diameter and a ...
Dean Mason N - - 2011
Chimaera (Holocephali) are cartilaginous fishes with flexible operculi rather than external gill slits, suggesting ventilation occurs in a manner different from other fishes. We examined holocephalan ventilation morphology, behavior, and performance by anatomical investigations, high-speed video, and in vivo pressure measurements from the buccal and parabranchial cranial cavities in Hydrolagus ...
Jiang Kai - - 2011
Bismuth ferrite (BiFeO$_3$) nanocrystalline films with the crystalline size of 27-40 nm have been grown on {\it c}-sapphire substrates under various oxygen pressures of 10$^{-4}$-1 Pa by pulsed laser deposition. The X-ray diffraction spectra show that the films are polycrystalline and present the pure rhombohedral phase. It was found that ...
Sonoda H - - 2011
The present study investigated factors that modify or affect arterial stiffness as assessed by brachial-ankle pulse wave velocity (baPWV) in the general population. Subjects had previously participated in a physical checkup program (n=911), and baPWV and urinary albumin and sodium excretion were also measured. Urine albumin was expressed as the ...
Sakka L - - 2011
The cerebrospinal fluid (CSF) is contained in the brain ventricles and the cranial and spinal subarachnoid spaces. The mean CSF volume is 150ml, with 25ml in the ventricles and 125ml in subarachnoid spaces. CSF is predominantly, but not exclusively, secreted by the choroid plexuses. Brain interstitial fluid, ependyma and capillaries ...
Manisty Charlotte H CH International Centre for Circulatory Health, Imperial College London, London, UK. - - 2012
The AV delay optimization of biventricular pacemakers (cardiac resynchronization therapy) may maximize hemodynamic benefit but consumes specialist time to conduct echocardiographically. Noninvasive BP monitoring is a potentially automatable alternative, but it is unknown whether it gives the same information and similar precision (signal/noise ratio). Moreover, the immediate BP increment on ...
Trautmann Caroline - - 2011
Abstract Plantar pressure characteristics during fencing movements may provide more specific information about the influence of foot loading on overload injury patterns. Twenty-nine experienced fencers participated in the study. Three fencing-specific movements (lunge, advance, retreat) and normal running were performed with three different shoe models: Ballestra (Nike, USA), Adistar Fencing ...
Heulitt Mark J - - 2011
OBJECTIVE:: Our objective was to compare response time, pressure time product as a reflection of work of breathing, and incidence and type of asynchrony in neurally vs. pneumatically triggered breaths in a spontaneously breathing animal model with resolving lung injury. DESIGN:: Prospective animal study. SETTING:: Experimental laboratory. SUBJECTS:: Male Yorkshire ...
Li Bassi Gianluigi - - 2011
OBJECTIVES:: During mechanical ventilation, air flows may play a role in mucus transport via two-phase gas liquid flow. The aim of this study was to evaluate effects of duty cycles and positive end-expiratory pressure on mucus clearance in pigs using mechanical ventilation, and to assess their safety. DESIGN:: Prospective randomized ...
Seitz Andreas Martin - - 2011
We examined the influence of partial meniscectomy of 10 mm width on 10 human cadaveric knee joints, as it is performed during the treatment of radial tears in the posterior horn of the medial meniscus, on maximum contact pressure, contact area (CA), and meniscal hoop strain in the lateral and medial ...
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 ...
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