Abstract Purpose: To investigate, using laser speckle flowgraphy (LSFG), the autoregulation of ocular blood flow (BF) in response to posture change. Methods: This study comprised 20 healthy volunteers (mean age 30.0 ± 8.5). The mean blur rate (MBR) of the ocular circulation in the subjects was assessed in both a sitting and ...

BACKGROUND: To assess acute effects of bevacizumab (anti-VEGF therapy) on cerebral microvessels and systemic cardiovascular regulation.Design and subjects: 20 consecutive patients with colorectal cancer (median age: 60.4 years, range 45.5-73.9 years) received bevacizumab intravenously (5 mg/kg) uncoupled of chemotherapy. Prior to and within the first 24 hours after bevacizumab infusion, ...

OBJECTIVE: Abnormalities in retinal vessels are frequent, but its association with findings in other vascular sites has been scarcely investigated. This study aimed to examine the association between ultrasound-measured carotid intima-media thickness (IMT) and retinal arteriolar and venular diameters, in hypertensive patients. METHODS: In this cross-section study, 173 hypertensive patients ...

PURPOSE:: To evaluate the effects and safety of travel by land through high mountainous elevations after surgery in patients who have undergone pars plana vitrectomy with intraocular gas. METHODS:: A retrospective cohort study of 75 patients post pars plana vitrectomy with intraocular gas who traveled by land through mountain elevations ...

Abstract Purpose: To assess whether dorzolamide 2%-timolol 0.5% (D/T) and/or brimonidine 0.2%-timolol 0.5% (B/T) alters retinal vascular autoregulation (RVA) and seated ocular perfusion pressure (sOPP) in primary open angle glaucoma (POAG) patients who demonstrate retinal vascular dysregulation (RVD) on timolol 0.5% alone. Methods: In this prospective, observer-masked, crossover study, 21 ...

PURPOSE:To report the tomographic and biomechanical findings before and after treatment of a case of pressure-induced stromal keratopathy (PISK), which was misdiagnosed as diffuse lamellar keratitis (DLK). METHODS:A case report of a referred patient with supposed diagnosis of DLK after LASIK in the right eye. Scheimpflug-based corneal tomography and biomechanical ...

BACKGROUNDWe examined the relationship between arterial hypertension, localized retinal nerve fiber layer defects (RNFLDs), and retinal vascular abnormalities.METHODSThe study included 359 patients with arterial hypertension and 331 individuals without hypertension as control subjects. Localized RNFLDs and retinal vascular abnormalities were assessed on fundus photographs.RESULTSAfter adjusting for blood concentrations of glycosylated ...

Amyl nitrite 'poppers' are recreational drugs, which are a potent source of nitric oxide. The use of 'poppers' can cause psychoactive stimulation, reduced blood pressure, tachycardia and involuntary muscle relaxation. Their use is becoming increasingly common around the world, including approximately 60% of Australia's male homosexual community. We report the ...

An asymmetric moissanite anvil cell is used to study aqueous solutions of ammonium iodide at pressures up to 10 kbar. The index of refraction is measured using the rotating Fabry-Perot technique, with an accuracy of approximately 1%. The mass density and molar volume of the solutions are estimated using the ...

PURPOSE: To explore the association of age-related macular degeneration (AMD) with long-term average blood pressure (BP) parameters, including pulse pressure (PP). Methods: The Alienor study is a population-based study on age-related eye diseases in 963 residents of Bordeaux (France), aged 73 years or more. AMD was graded from non mydriatic ...

We explored the technological concept of the nanoparticle structuring in the wedge film with regards to its application to the oily soil removal phenomena. The experimental and theoretical investigations on the cleansing of canola oil from a glass substrate using commercially available nanofluids were pursued. Five commercially-available nanofluids with pHs ...

Hole-some mixture: A 2D mesoporous covalent organic framework featuring expanded pyrene cores and linked by imine linkages has high surface area (SA(BET) =2723 m(2)  g(-1) ) and exhibits significant gas storage capacities under high pressure, which make this class of material very promising for gas storage applications.

OPINION STATEMENT: Idiopathic intracranial hypertension (IIH, pseudotumor cerebri) is a syndrome of elevated intracranial pressure of unknown cause that occurs predominantly in obese women of childbearing age. It is a diagnosis of exclusion and, therefore, other causes of increased intracranial pressure must be sought with history, imaging, and cerebrospinal fluid ...

We report ocular changes occurring in a healthy human subject enrolled in a bed rest (BR) study designed to replicate the effects of a low-gravity environment. A 25-yr-old Caucasian man spent 30 consecutive days in a 6 degrees head-down tilt (HDT) position at the NASA Flight Analogs Research Unit. Comprehensive ...

We report that the shape, orientation, edge geometry and thickness of chemical vapour deposition graphene domains can be controlled by the crystallographic orientations of Cu substrates. Under low-pressure conditions single layer graphene domains align with zig-zag edges parallel to a single <101> direction on Cu(111) and Cu(101), while bilayer domains ...

INTRODUCTION Increasing evidence suggests that arterial hypertension (AHT) may begin in childhood and result in the premature development of cardiovascular disease. In view of this, we believed it would be important to investigate the early vascular changes related to early hypertension at the micro- and macrovascular levels both under normal ...

The diffusion coefficients D(12) of phenylbutazone at infinite dilution in supercritical CO(2) were measured by the chromatographic impulse response (CIR) method. The measurements were carried out over the temperature range from 308.2 to 343.2K at pressures up to 40.0MPa. In addition, the D(12) data of phenylbutazone at infinite dilution in ...

BACKGROUND Hypertensive patients with retinal arteriolar abnormalities are at increased risk for cardiovascular events. However, the extent of retinal microvascular changes in naïve, never-treated patients with hypertension of short duration has not been established. In addition to this, the lack of relevant data about other phenotypes of hypertension (masked and ...

OBJECTIVE: Hypertension is characterized by microvascular remodeling resulting in increased wall/lumen ratio and elevated microvascular stiffness. Aiming to transform the measurement of macrovascular stiffness into a microvascular environment we introduce a non-invasive method to assess retinal pulse wave velocity (rPWV). rPWV alterations in early hypertension are investigated in detail. The ...

A novel method for the characterization and qualification of Hall effect thruster propellant distributors is presented. A quantitative measurement of the azimuthal number density uniformity, a metric which impacts propellant utilization, is obtained from photographs of a premixed flame anchored on the exit plane of the propellant distributor. The technique ...

The purpose of this study was to compare postoperative intraocular pressures and percentage of vitreous cavity gas fill one day following 25-gauge pars plana vitrectomy with 20% versus 25% sulfur hexafluoride (SF6) gas fill. This was a retrospective review of 187 consecutive cases of 25-gauge pars plana vitrectomy with complete ...

Intraocular pressure is affected by corneal thickness and biomechanics. Following ablative corneal refractive surgery, corneal structural changes occur. The purpose of the study is to determine the relationship between the mean central corneal thickness (CCT) and the change in intraocular pressure measurements following various corneal ablation techniques, using different measurement ...

PURPOSE: To determine using retrospective file analysis which clinical factors best predicted glaucomatous optic neuropathy as determined using Heidelberg Retinal Tomography (HRT II) imaging. METHODS: 122 records meeting inclusion criteria for this study were reviewed from patients referred for HRT imaging at the University of Waterloo Ocular Heath Clinic (UWOHC). ...

ZnO thin films were prepared by the polymeric precursor method. The films were deposited on silicon substrates using the spin-coating technique, and were annealed at 330 °C for 32 h under pressure-assisted thermal annealing and under ambient pressure. Their structural and optical properties were characterized, and the phases formed were identified by ...

Sound velocities of vitreous silica are measured under He compression in the pressure range of 0-6 GPa by Brillouin light scattering. It is found that the well-known anomalous maximum in the pressure dependence of the compressibility is suppressed by He incorporation into the silica network. This shows that the elastic anomaly ...

PURPOSE: To examine which prognostic factors are associated with glaucomatous visual field progression. DESIGN: Knowledge of prognostic factors helps clinicians to select patients at risk of glaucomatous visual field progression and intensify their treatment. METHODS: By consulting relevant databases, we identified 2733 articles published up to September 2010, of which ...

In our paper, we study the interface wettability, diffusivity and molecular orientation between crude oil and different fluids for applications in Improved Oil Recovery (IOR) processes through atomistic Molecular Dynamics (MD). The salt concentration, temperature and pressure effects on the physical chemistry properties of different interfaces between IOR agents [brine ...

The high-normal blood pressure (also known as prehypertension) is a clinical condition characterized by an increased cardiovascular risk as well as by the presence of target organ damage. This include an increased left ventricualr mass, an endothelial dysfunction and an early renal functional and structural damage. Whether this is the ...

PURPOSE: In this study, we examine the association of blood pressure (BP), retinal thickness (RT), and vessel caliber in patients with type 2 diabetes and high HbA1c (elevated long-term blood glucose) with or without mild or moderate nonproliferative diabetic retinopathy (NPDR). METHODS: Forty-three patients with type 2 diabetes and high ...

Thermal fluctuations strongly modify the large length-scale elastic behavior of cross-linked membranes, giving rise to scale-dependent elastic moduli. Whereas thermal effects in flat membranes are well understood, many natural and artificial microstructures are modeled as thin elastic shells. Shells are distinguished from flat membranes by their nonzero curvature, which provides ...

The effect of thermal processing (85-130°C) and combined thermal/high pressure processing (100°C combined with 0.1 to 700MPa and 700MPa combined with 85-115°C) on β-carotene isomerisation in an olive oil/carrot emulsion and pure olive oil phase enriched with carrot β-carotene was investigated. Thermal processing always resulted in an increase in the ...

The melting curve of lithium between ambient pressure and 64 GPa is measured by detection of an abrupt change in its electrical resistivity at melting and by visual observation. Here we have used a quasi-four-point resistance measurement in a diamond anvil cell and measured the resistance of lithium as it goes ...

We report the design, realization, and test of a high-pressure optical cell that we have used to measure the Raman spectra of hydrogen clathrate hydrates, synthesized in situ by the application of 200-300 MPa of gas pressure on solid water. The optical apparatus is mounted on a cryogenic system so ...

Investigating how intrathoracic pressure changes affect cerebral blood flow (CBF) is important for a clear interpretation of neuroimaging data in patients with abnormal respiratory physiology, intensive care patients receiving mechanical ventilation and in research paradigms that manipulate intrathoracic pressure. Here, we investigated the effect of experimentally increased and decreased intrathoracic ...

We introduce a novel technique that enables pressure measurements to be made in microfluidic chips using optical trapping. Pressure differentials across droplets in a microfluidic channel are determined by monitoring the displacements of a bead in an optical trap. We provide physical interpretation of the results. Our experiments reveal that ...

Background/Aims: The effects of haemodialysis on the microcirculation are poorly understood. This study examined the changes in small vessel calibre. Methods: 24 patients (including 12 males, median age 62.5 years, range 30-87) underwent digital retinal photography immediately before and after routine haemodialysis. Arteriolar and venular calibres were measured from the ...

An investigation into the effect of clinical ultrasound exposure on adherent microbubbles is described. A flow phantom was constructed in which targeted microbubbles were attached using biotin-streptavidin linkages. Microbubbles were insonated by broadband imaging pulses (centred at 2.25 MHz) over a range of pressures (peak negative pressure (PNP) = 60-375 kPa). ...

Collateral arterioles enlarge in both diameter and length, and develop corkscrew-like tortuous patterns during remodeling. Recent studies showed that artery buckling could lead to tortuosity. The objective of this study was to determine arteriole critical buckling pressure and buckling pattern during arteriole remodeling. Arterioles were modeled as elastic cylindrical vessels ...

Colloidal capsules can sustain an external osmotic pressure; however, for a sufficiently large pressure, they will ultimately buckle. This process can be strongly influenced by structural inhomogeneities in the capsule shells. We explore how the time delay before the onset of buckling decreases as the shells are made more inhomogeneous; ...

The ocular circulation provides readily visible information about the state of the systemic circulation, as well as being potentially of relevance to the pathogenesis of ocular disorders such as glaucoma. The interaction between intraocular pressure, retinal vessels and cerebrospinal fluid pressure located at the retrolaminar portion of the eye has ...

Ethylene glycol (EG) is a model system for studying complex hydrogen bonding networks in biological compounds such as polysaccharides and sugars. Using in-situ high pressure Raman and infrared absorption spectroscopy, we have investigated the pressure induced variation in the conformations and hydrogen bonding interactions in this compound up to 10 ...

We present a case of bilateral simultaneous central serous chorioretinopathy (CSCR) in a teenage girl with a history of systemic arterial hypertension. A 19-year-old Caucasian female, with a history of systemic arterial hypertension, presented with gradual decrease in her central vision for 1 month. She was diagnosed with bilateral simultaneous CSCR, ...

High-pressure and high-temperature Brillouin scattering studies have been performed on liquid of composition corresponding to the ammonia dihydrate stoichiometry (NH(3)[middle dot]2H(2)O) in a diamond anvil cell. Using the measured Brillouin frequency shifts from 180° back- and 60° platelet-scattering geometries, the acoustic velocity, refractive index, density, and adiabatic bulk modulus have ...

PURPOSE:: To evaluate preretinal partial pressure of oxygen (PO2) gradients before and after experimental pars plana vitrectomy. METHODS:: Arteriolar, venous, and intervascular preretinal PO2 gradients were recorded in 7 minipigs during slow withdrawal of oxygen-sensitive microelectrodes (10-μm tip diameter) from the vitreoretinal interface to 2 mm into the vitreous cavity. ...

The purpose of this study was to investigate the roles of endothelium-derived factors in the retinal arteriolar responses to acute severe elevation in systemic blood pressure (BP) in cats. Acute elevation of mean arterial BP by 60% for 5 min was achieved by inflating a balloon-tipped catheter in the descending aorta. ...

A laboratory-scale submerged anaerobic membrane bioreactor (SAnMBR) treating sewage was used to investigate the membrane fouling mechanism. Characterization of cake layer formed on membrane surface showed that cake layer was hydrated, rich of extracellular polymeric substances (EPS) and negative charged with the charge density of 0.21-0.46meq/kg MLSS. Detailed analysis revealed ...

Cerebrospinal fluid pressure (CSFp) provides vital information in various neurological abnormalities including hydrocephalus, intracranial hypertension and brain tumors. Currently, CSFp is measured invasively through implanted catheters within the brain (ventricles and parenchyma) which is associated with a risk of infection and morbidity. In humans, the cerebrospinal fluid communicates indirectly with ...

A liquid drop impacting a solid surface may splash either by emitting a thin liquid sheet that subsequently breaks apart or by promptly ejecting droplets from the advancing liquid-solid contact line. Using high-speed imaging, we show that surface roughness and air pressure influence both mechanisms. Roughness inhibits thin-sheet formation even ...

J Clin Hypertens (Greenwich). 2012; 14:630-636. © 2012 Wiley Periodicals, Inc. The possible effects of sesame oil on hemodynamics are unknown. The aim of the study was to investigate the acute and long-term effects of sesame oil on hemodynamic responses in hypertensive men. The authors enrolled 30 hypertensive men in ...

A variety of mechanical and laser-based methods remove or shift atherosclerotic plaques and reopen the artery to its original lumen. Subsequent treatment with drug-coated balloons (DCB) may smooth the vessel wall but does not require high-pressure inflation. We investigated the efficacy of paclitaxel-coated balloons inflated with only 2 atm after bare ...