Alterations to peritubular capillary structure in a rat model of kidney interstitial fibrosis: Implications for oxygen diffusion.

Fibrosis and loss of functional capillary surface area may contribute to renal tissue hypoxia in a range of kidney diseases. However, there is limited quantitative information on the impact of kidney disease on the barriers to oxygen diffusion from cortical peritubular capillaries (PTCs) to kidney epithelial tubules. Here, we used stereological methods to quantify changes in total cortical PTC length and surface area, PTC length and surface densities, and diffusion distances between PTCs and kidney tubules in adenine-induced kidney injury.

Inverse Estimation of Moisture Diffusion Model for Concrete Using Artificial Neural Network.

In this research, the moisture diffusion model for concrete was inversely estimated using artificial neural network (ANN) and the data collected from virtual experiments. In addition, the moisture distribution was predicted using the ANN model in numerical analysis. For inverse estimation, virtual experimental data were used.

Spatial composition and turnover of the main molecules in the adult glomerular basement membrane.

The glomerular basement membrane (GBM) is an important tissue structure in kidney function. It is the membrane through which filtrate and solutes must pass to reach the nephron tubules. This review focuses on the spatial location of the main extracellular matrix components of the GBM.

Hyaluronan Synthase 1: A Novel Candidate Gene Associated With Late-Onset Non-syndromic Hereditary Hearing Loss.

Objectives: Hyaluronan synthase 1 (HAS1) is a membrane-bound protein that is abundant in the epidermis and dermis, and it is important for skin function. However, its association with hearing loss has not yet been studied. Herein, we sought to evaluate the potential contribution of HAS1: c.

Predicting oxygen tension along the ureter.

Continuous measurement of bladder urine oxygen tension (Po) is a method to potentially detect renal medullary hypoxia in patients at risk of acute kidney injury (AKI). To assess its practicality, we developed a computational model of the peristaltic movement of a urine bolus along the ureter and the oxygen exchange between the bolus and ureter wall. This model quantifies the changes in urine Po as urine transits from the renal pelvis to the bladder.

Estimating outflow facility parameters for the human eye using hypotensive pressure-time data.

We have previously developed a new theory for pressure dependent outflow from the human eye, and tested the model using experimental data at intraocular pressures above normal eye pressures. In this paper, we use our model to analyze a hypotensive pressure-time dataset obtained following application of a Honan balloon. Here we show that the hypotensive pressure-time data can be successfully analyzed using our proposed pressure dependent outflow model.

A cardiovascular model for renal perfusion during cardiopulmonary bypass surgery.

Acute kidney injury (AKI) is a major complication following cardiac surgery requiring cardiopulmonary bypass (CPB). It is likely that poor renal perfusion contributes to the occurrence of AKI, via renal hypoxia, so it is imperative to maintain optimal renal perfusion during CPB. We have developed a straightforward cardiovascular perfusion model with parameter values calibrated against experimental and/or clinical data from several independent studies of CPB in humans and animals.

No flow through the vitreous humor: How strong is the evidence?

When analyzing vitreal drug delivery, or the pharmacological effects of drugs on intraocular pressure, or when interpreting outflow facility measurements, it is generally accepted that the fluid in the vitreous humor is stagnant. It is accepted that for all practical purposes, the aqueous fluid exits the eye via anterior pathways only, and so there is negligible if any posteriorly directed flow of aqueous through the vitreous humor. This assumption is largely based on the interpretation of experimental data from key sources including Maurice (1957), Moseley (1984), Gaul and Brubaker (1986), Maurice (1987) and Araie et al.

Renal oxygenation: From data to insight.

Computational models have made a major contribution to the field of physiology. As the complexity of our understanding of biological systems expands, the need for computational methods only increases. But collaboration between experimental physiologists and computational modellers (ie theoretical physiologists) is not easy.

PMFF: Development of a Physics-Based Molecular Force Field for Protein Simulation and Ligand Docking.

The physics-based molecular force field (PMFF) was developed by integrating a set of potential energy functions in which each term in an intermolecular potential energy function is derived based on experimental values, such as the dipole moments, lattice energy, proton transfer energy, and X-ray crystal structures. The term "physics-based" is used to emphasize the idea that the experimental observables that are considered to be the most relevant to each term are used for the parameterization rather than parameterizing all observables together against the target value. PMFF uses MM3 intramolecular potential energy terms to describe intramolecular interactions and includes an implicit solvation model specifically developed for the PMFF.

What Makes the Kidney Susceptible to Hypoxia?

Per gram of tissue, the kidneys are among our most highly perfused organs. Yet the renal cortex and, in particular, the renal medulla are susceptible to hypoxia. In turn, hypoxia is a major pathophysiological feature of both acute kidney injury and chronic kidney disease.

Analysis of the critical determinants of renal medullary oxygenation.

We have previously developed a three-dimensional computational model of oxygen transport in the renal medulla. In the present study, we used this model to quantify the sensitivity of renal medullary oxygenation to four of its major known determinants: medullary blood flow (MBF), medullary oxygen consumption rate (V̇o), hemoglobin (Hb) concentration in the blood, and renal perfusion pressure. We also examined medullary oxygenation under special conditions of hydropenia, extracellular fluid volume expansion by infusion of isotonic saline, and hemodilution during cardiopulmonary bypass.

Estimating three-dimensional outflow and pressure gradients within the human eye.

In this paper we set the previously reported pressure-dependent, ordinary differential equation outflow model by Smith and Gardiner for the human eye, into a new three-dimensional (3D) porous media outflow model of the eye, and calibrate model parameters using data reported in the literature. Assuming normal outflow through anterior pathways, we test the ability of 3D flow model to predict the pressure elevation with a silicone oil tamponade. Then assuming outflow across the retinal pigment epithelium is normal, we test the ability of the 3D model to predict the pressure elevation in Schwartz-Matsuo syndrome.

Stimulation of erythropoietin release by hypoxia and hypoxemia: similar but different.

Erythropoietin is released from the kidney in response to tissue hypoxia. Montero and Lundby found that increases in plasma erythropoietin induced by reducing arterial oxygen content in healthy humans were independent of arterial oxygen tension. Their observations accord with the established physiology of kidney oxygenation and can be predicted by a computational model of renal oxygen transport.

Revisiting the Effect of Slag in Reducing Heat of Hydration in Concrete in Comparison to Other Supplementary Cementitious Materials.

Blast furnace slag (SL) is an amorphous calcium aluminosilicate material that exhibits both pozzolanic and latent hydraulic activities. It has been successfully used to reduce the heat of hydration in mass concrete. However, SL currently available in the market generally experiences pre-treatment to increase its reactivity to be closer to that of portland cement.

A model of oxygen transport in the rat renal medulla.

The renal medulla is prone to hypoxia. Medullary hypoxia is postulated to be a leading cause of acute kidney injury, so there is considerable interest in predicting the oxygen tension in the medulla. Therefore we have developed a computational model for blood and oxygen transport within a physiologically normal rat renal medulla, using a multilevel modeling approach.

Iatrogenic Development of Cerebrospinal Fluid Leakage in Diagnosing Spontaneous Intracranial Hypotension.

A 34-year-old woman came to the emergency room complaining of a severe orthostatic headache. Results of a cerebrospinal fluid tap and brain computed tomography were normal. Based on her history and symptoms, she was found to have spontaneous intracranial hypotension.

Accounting for oxygen in the renal cortex: a computational study of factors that predispose the cortex to hypoxia.

We develop a pseudo-three-dimensional model of oxygen transport for the renal cortex of the rat, incorporating both the axial and radial geometry of the preglomerular circulation and quantitative information regarding the surface areas and transport from the vasculature and renal corpuscles. The computational model was validated by simulating four sets of published experimental studies of renal oxygenation in rats. Under the control conditions, the predicted cortical tissue oxygen tension ([Formula: see text]) or microvascular oxygen tension (µPo) were within ±1 SE of the mean value observed experimentally.

A pseudo-three-dimensional model for quantification of oxygen diffusion from preglomerular arteries to renal tissue and renal venous blood.

To assess the physiological significance of arterial-to-venous (AV) oxygen shunting, we generated a new pseudo-three-dimensional computational model of oxygen diffusion from intrarenal arteries to cortical tissue and veins. The model combines the 11 branching levels (known as "Strahler" orders) of the preglomerular renal vasculature in the rat, with an analysis of an extensive data set obtained using light microscopy to estimate oxygen mass transfer coefficients for each Strahler order. Furthermore, the AV shunting model is now set within a global oxygen transport model that includes transport from arteries, glomeruli, peritubular capillaries, and veins to tissue.

Nanophase Changes in Nickel Doped Titania Composites by Thermal Treatment and Photocatalytic Destruction of NO(x).

This study investigated the influence of Ni doping and thermal treatment (600, 800 degrees and 1000 degrees C) on the physiochemical properties of a commercially available low cost KA100 TiO2. Ni containing KA100 samples were prepared with different loading of Ni (3%, 6% and 9% wt to KA100) and subjected to heat treatement at 600 degrees, 800 degrees and 1000 degrees C. The as-prepared samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Diffuse reflection UV-Visible spectroscopy and Raman spectroscopy and nitrogen-adsorption-desorption measurements to observe the nanophase changes in the particle characteristics following Ni modification and thermal treatment.

Difficult intubation using intubating laryngeal mask airway in conjunction with a fiber optic bronchoscope.

When anesthesiologists encounter conditions in which intubation is not possible using a conventional direct laryngoscope, they can consider using other available techniques and devices such as fiber optic bronchoscope (FOB)-guided intubation, a laryngeal mask airway (LMA), intubating LMA (ILMA), a light wand, and the Combitube. FOB-guided intubation is frequently utilized in predicted difficult airway cases and is generally performed when the patient is awake to enable easier access to the trachea. An LMA can be introduced to ventilate the patient with relative ease, while an ILMA can be used for definite endotracheal intubation.

The influence of flow diverter's angle of curvature across the aneurysm neck on its haemodynamics.

Flow diverter stents have provided a new method of endovascular reconstruction for large and complex aneurysms. Understanding the impact of the flow diverter's angle of curvature across the neck and its metal coverage rate on the haemodynamics of aneurysm is crucial to maximize the mass flow reduction inside the aneurysm, post-deployment. The aim of this study is to understand the correlation between the angle of curvature of flow diverter across the aneurysm neck and the metal coverage rate, and the aneurysm's haemodynamics, using computational fluid dynamics.

Effect of Microorganism Sporosarcina pasteurii on the Hydration of Cement Paste.

Years of research have shown that the application of microorganisms increases the compressive strength of cement-based material when it is cured in a culture medium. Because the compressive strength is strongly affected by the hydration of cement paste, this research aimed to investigate the role of the microorganism Sporosarcina pasteurii in hydration of cement paste. The microorganism's role was investigated with and without the presence of a urea-CaCl2 culture medium (i.

Identification of a hemodynamic parameter for assessing treatment outcome of EDAS in Moyamoya disease.

This work is a novel attempt to incorporate computational fluid dynamics (CFD) techniques in the analysis of hemodynamic parameters of Moyamoya disease (MMD). Highly prevalent in Asian countries, MMD is characterised by progressive occlusion of the intracranial Internal Carotid Arteries (ICA). We intend to identify a reliable hemodynamic parameter that can be used to gauge treatment outcome.

Three-dimensional hemodynamic design optimization of stents for cerebral aneurysms.

Flow-diverting stents occlude aneurysms by diverting the blood flow from entering the aneurysm sac. Their effectiveness is determined by the thrombus formation rate, which depends greatly on stent design. The aim of this study was to provide a general framework for efficient stent design using design optimization methods, with a focus on stent hemodynamics as the starting point.