ObjectiveTo estimate the heritability of myocardial blood flow (MBF) and coronary flow reserve (CFR) measured with positron emission tomography (PET).DesignCross-sectional twin study.SettingGeneral clinical research centre of a university hospital at Atlanta, USA.PatientsA sample of 180 middle-aged (mean±SD 55±2.9 years) male twins, including 107 monozygotic and 73 dizygotic twins.Main outcome measuresAll ...

This research studies dynamic culture for 3D tissue construct development with computational fluid dynamics. It proposes a mathematical model to evaluate the impact of flow rates and flow shear stress on cell growth in 3D constructs under perfusion. The modeling results show that dynamic flow, even at flow rate as ...

BACKGROUND: Prenatal exposure to both stress and aeroallergens (dust mite) may modulate the fetal immune system. These exposures may interact to affect the newborn immune response. We examined associations between prenatal maternal stress and cord blood total IgE in 403 predominately low-income minority infants enrolled in the Asthma Coalition on ...

Background: Chronic obstructive pulmonary disease (COPD) is an inflammatory disease associated with reactive oxygen species (ROS) production. The aim of this study was to evaluate the effect of Hypoxen® treatment and the effect of HyFnC60 on ROS production in patients' blood.<br /> Material/Methods: ROS production in blood was estimated using ...

Тo examine the effects of nitroglycerine on portal vein haemodynamics and oxidative stress in patients with portal hypertension. Thirty healthy controls and 39 patients with clinically verified portal hypertension and increased vascular resistance participated in the study. Liver diameters, portal diameters and portal flow velocities were recorded using color flow ...

Abstract Purpose: Environmental electromagnetic fields originate from man-made sources, such as mobile phones and base stations, and have led to increasing public concern about their possible adverse health effects. We aimed to investigate the possible effects of Radiofrequency radiation (RFR) generated from these devices on oversensitive animals, such as pregnant ...

A mathematical model was developed to study nitric oxide (NO) and oxygen (O(2)) transport in an arteriole and surrounding tissues exposed to a mixture of red blood cells (RBCs) and hemoglobin (Hb)-based O(2) carriers (HBOCs). A unique feature of this model is the inclusion of blood vessel wall shear stress-induced ...

The overall goal of this method is to describe a technique to subject adherent cells to laminar flow conditions and evaluate their response to well quantifiable fluid shear stresses(1). Our flow chamber design and flow circuit (Fig. 1) contains a transparent viewing region that enables testing of cell adhesion and ...

The validity of the flow-mediated dilation test has been questioned due to the lack of normalization to the primary stimulus, shear stress. Shear stress can be calculated using Poiseuille's law. However, little attention has been given to the most appropriate blood velocity parameter(s) for calculating shear stress. The pulsatile nature ...

The immune system, in cooperation with neuroendocrine functions, defends from cancer and infections mainly by the activity of blood natural killer (NK) cells. Blood NK activity may be influenced by the type of employment since work is the central part of life; moreover, job stress is a situation affecting both ...

We discuss the optimal evaluation of endothelial shear stress for real-life case studies based on anatomic data acquisition. The fluid dynamic simulations require smoothing of the geometric dataset to avoid major artefacts in the flow patterns, especially in the proximity of bifurcations. A systematic series of simulations at different corrugation ...

The flow behavior of a semiflexible polymer in microchannels is studied using multiparticle collision dynamics, a particle-based hydrodynamic simulation technique. Conformations, distributions, and radial cross-streamline migration are investigated for various bending rigidities, with persistence lengths L(p) in the range 0.5 ≤ L(p)/L(r) ≤ 30. The flow behavior is governed by ...

ABSTRACT: BACKGROUND: Functional and morphological changes of the heart influence blood flow patterns. Therefore, flow patterns may carry diagnostic and prognostic information. Three-dimensional, time-resolved, three-directional phase contrast cardiovascular magnetic resonance (4D PC-CMR) can image flow patterns with unique detail, and using new flow visualization methods may lead to new insights. ...

In the present paper, design of a flow control loop using a thyristor driven pump as final control element has been described. In this technique, the load current of a thyristor driven pump motor has been utilized as a mass flow sensing parameter of a fluid passing through a pipeline. ...

To propose a new noncontrast-enhanced flow-independent angiography sequence based on balanced steady-state free precession (bSSFP) that produces reliable vessel contrast despite the reduced blood flow in the extremities. The proposed technique addresses a variety of factors that can compromise the exam success including insufficient background suppression, field inhomogeneity, and large ...

In this work, we examine the dynamics of fluid flow in a mechanical heart valve when the solid inertia and leaflet compliance are important. The fluid is incompressible and Newtonian, and the leaflet is an incompressible neo-Hookean material. In the case of an inertialess leaflet, we find that the maximum ...

A novel in vitro flow through technique was developed and evaluated for immunodiagnosis of cystic echinococcosis in sheep using hydatid specific non-cross reactive 8-kDa protein. The 8-kDa protein was prepared from hydatid cyst fluid by DEAE-Sepharose fast flow anion exchange chromatography. In this flow through technique, the 8-kDa antigen was ...

In (19)F MRI oximetry, a method used to image tumour hypoxia, perfluorocarbons serve as oxygenation markers. The goal of this study is to evaluate the impact of perfluorocarbon distribution and concentration in (19)F MRI oximetry through a computer simulation. The simulation studies the correspondence between (19)F measured (pO(FNMR)(2)) and actual ...

Ten essentials of synthesis in the flow mode, a new enabling technology in organic chemistry, are highlighted as flashlighted providing an insight into current and future issues and developments in this field.

SUMMARY: Flow-territory mapping by MR imaging ASL noninvasively provides a unique insight into the distribution of cerebral perfusion. The introduction of planning-free vessel-encoded pCASL made flow-territory mapping feasible for clinical use, though lack of individual planning could impede reproducibility of this technique. We assessed the reproducibility of planning-free vessel-encoded pCASL ...

A two-fluid electroosmotic flow in a microchannel is studied by considering full hydrodynamic and electrostatic interactions on the interface. Jumps in electrical potential and in charge density across the interface, in particular, are found to create counterintuitive flow behavior through the electrostatic interaction of the interface with the external field ...

Transfer insensitive labeling technique (TILT) was previously applied to acquire multislice cerebral blood flow maps as a pulsed arterial spin labeling (PASL) method. The magnetization transfer effect with TILT is well controlled by using concatenated radiofrequency pulses. However, use of TILT has been limited by several challenges, including slice profile ...

A simple one-step flow focusing method was used to embed both magnetic nanoparticles and quantum dots in microbeads in controlled ratios to generate a large library of molecular barcodes for biological applications.

We report a finding of spontaneous flow reversals of roll-like patterns in liquid gallium Rayleigh-Bénard convection. The vessel has a square geometry with an aspect ratio of 5, and a horizontal magnetic field is applied to align the rolls. The flow patterns were visualized by ultrasonic velocity measurements, and the ...

Supraglottal jet variability was investigated in a scaled-up flow facility incorporating driven vocal fold models with and without wall rotation. Principle component analysis was performed on the experimental supraglottal flow fields to ascertain the roll of glottal wall motion on the development of the supraglottal jet. It is shown that ...

Hemoglobin Pôrto Alegre (PA) is a rare hemoglobin resulting from a mutation in β9(A6)Ser → Cys. We describe an asymptomatic Puerto Rican female with combined heterozygosity for Hb PA and Hb S. Since birth, she has maintained normal hemoglobin, bilirubin, LDH levels, and reticulocyte count. Peripheral smear evaluation has revealed normal erythrocyte ...

In magnetic drug delivery, therapeutic magnetizable particles are typically injected into the blood stream and magnets are then used to concentrate them to disease locations. The behavior of such particles in-vivo is complex and is governed by blood convection, diffusion (in blood and in tissue), extravasation, and the applied magnetic ...

A magnitude-based MR angiography method of standard time-of-flight (TOF) employing a three-dimensional gradient-echo sequence with flow rephasing is widely used. A recently proposed flow-sensitive black-blood (FSBB) method combining three-dimensional gradient-echo sequence with a flow-dephasing gradient and a hybrid technique, called hybrid of opposite-contrast, allow depiction of smaller blood vessels than ...

Ultrasound Doppler (UD) velocity measurements are commonly used to quantify blood flow velocities in vivo. The aim of our work was to investigate the accuracy of in vivo spectral Doppler measurements of velocity waveforms. Waveforms were derived from spectral Doppler signals and corrected for intrinsic spectral broadening errors by applying ...

Evidence suggests that biological forms that provide physiological and autecological functions have evolved to adapt to environmental conditions and to optimise requisite morpho-functions. We examined whether shell morphology is functionally optimised to generate passive feeding flow in the Devonian spiriferide brachiopod Paraspirifer bownockeri. This study was based on quantitative results ...

This paper proposes image processing algorithms to recognize five types of white blood cells in peripheral blood automatically. First, a method based on Gram-Schmidt orthogonalization is proposed along with a snake algorithm to segment nucleus and cytoplasm of the cells. Then, a variety of features are extracted from the segmented ...

Pelagic copepods jump to relocate, to attack prey and to escape predators. However, there is a price to be paid for these jumps in terms of their energy costs and the hydrodynamic signals they generate to rheotactic predators. Using observed kinematics of various types of jumps, we computed the imposed ...

Alexis Carrel was awarded the 1912 Nobel Prize for Physiology or Medicine for pioneering surgical techniques in vascular surgery. His triangulation technique enabled successful anastomosis of blood vessels and subsequently led to advances in blood vessel and organ transplantation. However, Alexis Carrel did not limit his research to the vascular ...

Plane Poiseuille flow of a rarefied gas, which flows horizontally in the presence of strong gravitation, is studied based on the Boltzmann equation. Applying the asymptotic analysis for a small variation in the flow direction [Y. Sone, Molecular Gas Dynamics (Birkhäuser, 2007)], the two-dimensional problem is reduced to a one-dimensional ...

We report the first real-time observations of the entire fully developed laminar secondary flow field of aqueous 2% Viscarin GP-209NF (a λ-carrageenan polysaccharide) in a square duct as made using a modest rheological NMR imaging (rheo-NMR) apparatus. Simulations using the Reiner-Rivlin constitutive equation verify the results. An included rheo-NMR flow ...

Elution time measurements of colloidal particles injected in a symmetrical flow field-flow fractionation (flow FFF) system when the inlet and outlet cross-flow connections are closed have been performed. This no-field method has been proposed earlier for void time (and void volume) determination in flow FFF Giddings et al. (1977) [8]. ...

This paper describes a flow switching technique applicable to centrifugal microfluidic platforms, using a regulated stream of compressed gas. This pneumatic flow switching technique allows for flow control at a T-shaped junction between one inlet channel and two outlet channels. This technique provides a noncontact, robust, and efficient method for ...

PRACTICAL RELEVANCE: blood transfusions are a potentially life-saving procedure that are within the reach of most small animal practitioners. Only minimal equipment is required. PATIENT GROUP: any cat with clinical signs attributable to a reduced red blood cell mass that is affecting oxygen transport (as a result of reduced packed ...

Chemically or genetically modified hemoglobins are a therapeutic class indicated for the treatment of a variety of hypo-oxygenation pathologies, severe trauma-related hemorrhages or elective surgery when blood transfusions are refused or not available. Recombinant heterologous hemoglobins offer the possibility of a potentially unlimited production and genetically optimized properties in terms ...

Virtual blood bank is the computer-controlled, electronically linked information management system that allows online ordering and real-time, remote delivery of blood for transfusion. It connects the site of testing to the point of care at a remote site in a real-time fashion with networked computers thus maintaining the integrity of ...

The spatial arrangement of urban hubs and centers and how individuals interact with these centers is a crucial problem with many applications ranging from urban planning to epidemiology. We utilize here in an unprecedented manner the large scale, real-time 'Oyster' card database of individual person movements in the London subway ...

Blood banking has a broad public health impact influencing millions of lives daily. It could potentially benefit from emerging biopreservation technologies. However, although vitrification has shown advantages over traditional cryopreservation techniques, it has not been incorporated into transfusion medicine mainly due to throughput challenges. Here, we present a scalable method ...

This study aims to investigate the blood flow around the perivalvular area in a human superficial vein using high-frequency ultrasound (HFUS) speckle image velocimetry. HFUS B-mode images were captured from the superficial veins of human lower extremity with a 35-MHz transducer. To measure the instantaneous velocity fields of blood flow, ...

We report on the results of an experimental study established to optimize the design of microfabricated flow distributors for use in pressure-driven separations and reactions in flat-rectangular channels. For this purpose, the performance of a wide variety of possible flow distributor designs etched in glass/silicon wafers was compared, using CCD ...

Correct interpretation of tracer test data is critical for understanding transport processes in the subsurface. This task can be greatly complicated by the presence of intraborehole flows in a highly dynamic flow environment. At a new tracer test site (Hanford IFRC) a dynamic flow field created by changes in the ...

The problem of motion of the vortices around an oscillating cylinder in the presence of a uniform flow is considered. The Hamiltonian for vortex motion for the case with no uniform flow and stationary cylinder is constructed, reduced, and constant Hamiltonian (energy) curves are plotted when the system is shown ...

The supraglottal flow exhibits many complex phenomena such as recirculation, jet instabilities, jet attachment to one vocal fold wall, jet flapping, and transition to turbulence. The acoustical relevance of these flow structures to low-frequency voice production was evaluated by disturbing the supraglottal flow field using a cylinder and observing the ...

We describe the "chopsticks" technique of simultaneous use of two instruments held in one hand during tonsillectomy. The technique allows the surgeon to simultaneously, retract the tonsils, clear the blood, and cauterize the tissue and thus achieve rapid hemostasis and a more efficient tonsillectomy.

BACKGROUND: Transmitral pulse wave (PW) Doppler and annular tissue Doppler velocity measurements provide valuable diagnostic and prognostic information. However, they depend on an echocardiographer manually selecting positions to make the measurements. This is time-consuming and open to variability, especially by less experienced operators. We present a new, automated method to ...

Dynamic susceptibility contrast-MRI requires an arterial input function (AIF) to obtain cerebral blood flow, cerebral blood volume, and mean transit time. The current AIF selection criteria discriminate venous, capillary, and arterial profiles based on shape and timing characteristics of the first passage. Unfortunately, partial volume effects can lead to shape ...