Subsurface heterogeneity in hydraulic properties and processes is a fundamental challenge in hydrogeology. We have developed an improved method of borehole dilution testing for hydrostratigraphic characterization, in which distributed temperature sensing (DTS) is used to monitor advective heat movement. DTS offers many advantages over conventional technologies including response times in ...

The skin-blanching assay is used for the determination and bioequivalence of dermatologic glucocorticoids (GCs). The exact mechanism of the production of blanching is not fully understood, but it is considered that local vasoconstriction of the skin microvasculature and the consequent blood-flow reduction cause this phenomenon. Several factors influence skin blanching, ...

OBJECTIVE.: TheRhoA/Rho-kinase pathway plays a pivotal role in cold induced vasoconstriction, vascular smooth muscle cells function and vascular homeostasis. This study evaluates the efficacy of fasudil, a RhoA/Rho-kinase inhibitor, to reverse cold-induced vasospasm in patients with Raynaud's phenomenon (RP) secondary to systemic sclerosis (SSc). METHODS.: This is a single-center, double-blind, ...

Antivascular ultrasound consisting of low-intensity sonication in the presence of circulating microbubbles of an ultrasound contrast agent has been demonstrated to disrupt blood flow in solid cancers. In this study a mathematical framework is described for the microbubble-induced heating that occurs during antivascular ultrasound. Biological tissues are modeled as a ...

Background and Objectives  Previous studies have shown substantial geographical variation in blood donation within developed countries. To understand this issue better, we identified community characteristics associated with blood donor rates in German municipalities in an ecological analysis. Materials and Methods  We calculated an aggregated rate of voluntary blood donors from ...

An ideal diagnostic test for Alzheimer's disease (AD) should be non-invasive and easily applicable. Thus, there is a clear need to search for biomarkers in blood. In the present study, we have used multivariate data analysis [support vector machine (SVM)] to investigate whether a blood-based biomarker panel allows discrimination between ...

Obesity may cause adverse effects on the respiratory system. The main purpose of this study was to investigate how various measures of obesity are related to arterial blood gases and pulmonary function. This is a cross-sectional study of consecutive morbidly obese patients with normal lung function. Blood gas samples were ...

Hollow fiber oxygenators provide gas exchange to and from the blood during heart surgery or lung recovery. Minimal fiber surface area and optimal gas exchange rate may be achieved by optimization of hollow fiber shape and orientation (1). In this study, a modified CFD model is developed and validated with ...

We developed a mathematical model to simulate shear stress-dependent nitric oxide (NO) production and transport in a 3D microcirculatory network based on published data. The model consists of a 100 μm × 500 μm × 75 μm rectangular volume of tissue containing two arteriole-branching trees, and nine capillaries surrounding the vessels. Computed distributions for NO in blood, ...

The development of artificial oxygen carriers has attracted considerable recent interest because of the increasing cost of collecting and processing blood, public concerns about the safety of blood products, complications from blood transfusions, military requirements for increased volumes of blood during military conflicts, and a decrease in the number of ...

BACKGROUND: No reliable estimate of the prevalence of doping in elite sports has been published. Since 2001, the international governing body for athletics has implemented a blood-testing program to detect altered hematological profiles in world's top-level athletes. METHODS: A total of 7289 blood samples were collected from 2737 athletes out ...

BACKGROUND: Since no direct detection method for autologous blood transfusions exists, the most promising attempt is the Athlete Biological Passport (ABP) and its adaptive model that enables a longitudinal monitoring of hematologic measures to identify patterns of blood manipulations. The purpose therefore was to evaluate the performance of this adaptive ...

We investigate theoretically the nonlinear evolution of a sand bedform sheared by a laminar viscous flow. On the basis of the hydrodynamic equations coupled with a sediment transport law, we derive a closed nonlinear and nonlocal equation for the spatiotemporal evolution of the bedform profile in the case of an ...

We present a kinetic model for flowing active suspensions and analyze the behavior of a suspension subjected to a weak steady shear. Asymptotic solutions are sought in Deborah number expansions. At the leading order, we explore the steady states and perform their stability analysis. We predict the rheology of active ...

Patient specific geometrical data on human coronary arteries can be reliably obtained multislice computer tomography (MSCT) imaging. MSCT cannot provide hemodynamic variables, and the outflow through the side branches must be estimated. The impact of two different models to determine flow through the side branches on the wall shear stress ...

Blood loss can be measured directly and indirectly. The latter reflects blood loss through the assessment of hemoglobin level. Thus aim of this study was to determine the applicability of the drop in hemoglobin levels blood loss calculation when transfused blood volume is taken into account on the patients who ...

A method has been recently developed to reduce the confounding factors of extracranial origins on the intracranial latency (the time interval between the electrocardiogram QRS component and the initial inflection of the resulting pulse). Although, the proposed model was shown to portray a better characterization of cerebral vasculature, the parameters ...

There is accumulating evidence that exercise may improve disturbed haemorheological parameters that are typically observed in various chronic diseases, thus there is a growing interest in exploring the influence of various exercise models for the improvement of haemorheology. Blood sampling using venipuncture, however, can be limiting during exercise and/or in ...

Flow cytometry immunophenotyping (FCI) of hematolymphoid specimens is a powerful tool in clinical medicine aiding in the accurate diagnosis and subclassification of acute and chronic leukemias, non-Hodgkin lymphomas, myelodysplasia, and other hematolymphoid neoplastic processes. Multiple flow cytometric strategies are used to evaluate hematolymphoid populations, including identification of neoplastic populations with ...

Bioelectrical impedancemetry (BIA) has been used to evaluate hemorheological parameters in vitro, and whole body impedance measurements are also correlated to some hemorheologic factors, due to their close relationship with determinants of electric properties of blood. In previous studies, we have determined a set of predictive equations for hematocrit, whole ...

The ability to measure 25-hydroxyvitamin D (25OHD) levels from blood spot cards can simplify sample collection versus samples obtained by venipuncture, particularly in populations in whom it is difficult to draw blood. We sought to validate the use of blood spot samples for the measurement of 25OHD compared to serum ...

The identification of clinically meaningful and predictive models of disposition kinetics for cancer therapeutics is an ongoing pursuit in drug development. In particular, the growing interest in preclinical evaluation of anti-angiogenic agents alone or in combination with other drugs requires a complete understanding of the associated physiological consequences. Technescan™ PYP™, ...

To assess a pulmonary function change over time the mass flow sensor and the pneumotachograph are widely used in commercially available instruments. However, the smallest detectable change for both devices has never been compared. Therefore, the aim of this study is to determine the smallest detectable change in vital capacity ...

We report experiments on hard-sphere colloidal glasses that show a type of shear banding hitherto unobserved in soft glasses. We present a scenario that relates this to an instability due to shear-concentration coupling, a mechanism previously thought unimportant in these materials. Below a characteristic shear rate γ(c) we observe increasingly ...

OBJECTIVE: Massive perioperative blood product transfusion may be required with thoracic aortic operations and is associated with poor outcomes. We analyzed independent predictors of massive transfusion in thoracic aortic surgical patients undergoing deep hypothermic circulatory arrest. METHODS: The study consisted of 168 consecutive patients undergoing open thoracic aortic procedures involving ...

Objectives: Red blood cell concentrates (RCCs) are the major blood component transfused to patients. There is a great variability in patient response, depending on both the patient's blood volume and haemoglobin content in the RCC. Standardisation of transfusion practice is needed to improve the prediction of patient outcome. Aim: We ...

Karakosta P, Chatzi L, Plana E, Margioris A, Castanas E, Kogevinas M. Leptin levels in cord blood and anthropometric measures at birth: a systematic review and meta-analysis. Paediatric and Perinatal Epidemiology 2010. The role of intrauterine environment in the development of obesity is increasingly recognised. Adipokines and specifically leptin have ...

A typical blood bank gets its major supply of blood from organizing blood donation camps. The quantity of blood collected in the blood donation drives is random and it might be sensible to cut off the supply at some level to reduce the wastages by overcollection. In this paper we ...

Plasma skimming and the Fahraeus-Lindqvist effect are well-known phenomena in blood rheology. By combining these peculiarities of blood flow in the microcirculation with simple topological models of microvascular networks, we have uncovered interesting nonlinear behavior regarding blood flow in networks. Nonlinearity manifests itself in the existence of multiple steady states. ...

The Arrau turtle (Podocnemis expansa) is an endangered species, as a result of long-lasting, unsustainable exploitation. To obtain reference haematological values from the wild Podocnemis expansa during post-laying, 20 turtles were captured in the Orinoco River. Blood was obtained from the dorsal cervical sinus in lithium heparin tubes. Red blood ...

Computational modeling of bileaflet mechanical heart valve (BiMHV) flow requires experimentally validated datasets and improved knowledge of BiMHV fluid mechanics. In this study, flow was studied downstream of a model BiMHV in an axisymmetric aortic sinus using stereoscopic particle image velocimetry. The inlet flow was steady and the Reynolds number ...

Sympathetic nerve activity influences cerebral blood flow, but it is unknown whether augmented sympathetic nerve activity resets cerebral vasoreactivity to hypercapnia. This study tested the hypothesis that cerebral vasodilation during hypercapnia is restrained by lower-body negative pressure (LBNP)-stimulated sympathoexcitation. Cerebral hemodynamic responses were assessed in nine healthy volunteers [age 25 ...

ABSTRACT Cognitive impairment is common in persons with cardiovascular disease (CVD). Cardiac rehabilitation (CR) improves many aspects of CVD linked to cognitive impairment. The current study explored whether CR may improve cognitive function. Potential mechanisms for cognitive changes were also examined through exploratory analyses, including changes in cardiovascular fitness and ...

Cerebral autoregulation controls cerebral blood flow under changing cerebral perfusion pressure. Standards for measurement and analysis of dynamic cerebral autoregulation (dCA) are lacking. In this study, dCA reproducibility, quantified by intraclass correlation coefficient, is evaluated for different methodological approaches of transfer function analysis (TFA) and compared with multimodal pressure flow ...

Electrolyte- and acid-base-balance are relevant determinants for metabolic processes whose real time analysis is obligatory particularly in perioperative and intensive care treated patients. Also, the oxygenation status of the blood as a determinant for the oxygen supply of an organism and for the gas exchange is measured. By use of ...

Magnetic drug delivery refers to the physical confinement of therapeutic magnetic nanoparticles to regions of disease, tumors, infections and blood clots. Predicting the effectiveness of magnetic focusing in vivo is critical for the design and use of magnetic drug delivery systems. However, current simple back-of-the-envelope estimates have proven insufficient for ...

Autoregulation, an important feature of the cerebral circulation, is affected in many diseases. Since genetically modified mice are a fundamental tool in biomedical research, including neuro(bio)logy also in this specie measurements of cerebral autoregulation (CA) are mandatory. However, this requires anesthesia that unfortunately significantly impacts cerebral perfusion and consequently might ...

BACKGROUND AND PURPOSE: Cerebral autoregulation may become impaired after stroke. To provide a review of the nature and extent of any autoregulation impairment after stroke and its course over time, a technique allowing repeated bedside measurements with good temporal resolution is required. Transcranial Doppler (TCD) in combination with continuous blood ...

Mastication as a mild but life-long exercise has been examined as a possibility for maintaining brain function in the elderly. Little is known, however, about the cerebral circulatory response during masticatory movement. The aim of this study was to develop a monitoring system for circulation dynamics during masticatory movement and ...

In the recent years numerous studies have been undertaken to study cerebral perfusion in the surrounding of intracerebral hemorrhage, addressing the question of whether there is a secondary ischemic damage. Most of these studies found a reduced perfusion adjacent to the hematoma. However, the meaning of these findings remains controversial. ...

Neurovascular coupling and cerebral autoregulation are two brain intrinsic vasoregulative mechanisms that rapidly adjust local cerebral blood flow. This study examined if stenotic disease affects both mechanisms in the posterior cerebral artery. Ten patients with altogether 13 stenosed (≥50%) posterior cerebral artery (PCA) sides were studied. In addition, 6 control ...

Cardiovascular drugs play a major role in the pre- and postoperative care in neonates with congenital heart disease. Management strategies aim to optimise contractility, improve diastolic function, maintain adequate preload, and reduce afterload. Levosimendan, a novel inodilator agent, enhances myocardial contractility and causes peripheral and coronary vasodilation. A systematic approach ...

During exercise, as end-tidal carbon dioxide (P(ET)(CO₂)) drops after the respiratory compensation point (RCP), so does cerebral blood flow velocity (CBFv) and cerebral oxygenation. This low-flow, low-oxygenation state may limit work capacity. We hypothesized that by preventing the fall in P(ET)(CO₂) at peak work capacity (W(max)) with a newly designed ...

Objective. To investigate maternal cerebral blood flow and glucose metabolism in pregnancies complicated by severe preeclampsia compared to normal pregnancies. Methods. A prospective study was conducted including six women with severe preeclampsia and nine normotensive women. Transcranial Doppler (TCD) was performed pre- and postoperatively. The anterior, middle, and posterior cerebral ...

Divergent disease triggers in neurodegeneration may induce convergent endogenous pathways in neuronal, glial and vascular elements as the central nervous system (CNS) attempts to compensate, remodel and recover. Dissecting these multicellular mechanisms and the integrative responses in cerebral blood flow and metabolism may allow us to understand the balance between ...

The aim of the study is to assess the effects of an intravenous 10 mg/kg loading dose of caffeine base in cerebral oxygenation, cerebral Doppler blood flow velocity and cardiac output in preterm infants. Preterm neonates <34 weeks gestation were investigated at 1 and 4 h following the loading dose ...

OBJECTIVE: To determine the mean arterial pressure (MAP) and middle cerebral artery mean blood flow velocity (MFV) responses to 5 and 10mg midodrine during head-up tilt (HUT) in persons with tetraplegia. DESIGN: Prospective dose-response trial. SETTING: James J. Peters Veterans Administration Medical Center. PARTICIPANTS: Persons (N=10) with chronic tetraplegia (duration ...

The argument about why the head-up tilt table test (HUT) does not include the posterior cerebral circulation, which is mainly responsible for syncope, as a monitor target has not been resolved. It is also unclear whether there is a sex difference in cerebral blood flow (CBF) changes. We hypothesized that ...

During shoulder arthroscopy in the beach-chair position, cerebral ischemia may be a serious complication because prolonged hypotension may affect regional cerebral oxygen supply. We present the cases of 2 patients in whom a reduction in mean arterial pressure after anesthesia provoked a decrease in frontal lobe oxygenation to below the ...

A 77 year-old robust woman came to our emergency because of a sliding down accident. Dizziness was complained. There was no headache, vertigo, paresthesia, hearing block, ataxia or other neurological signs. She was alert and oriented to time, place and people. Glasgow scale was E4V5M6. Emergent computed tomography did not ...