Improved Hematology Analysis Based on Microfluidic Impedance Spectroscopy: Erythrocyte Orientation and Anisotropic Dielectric Properties of Flowing Blood.

Electrochemical impedance spectroscopy has great potential for laboratory blood tests. The overall aim of this study is to develop a microfluidic sensor for determining the physical properties and hematological parameters of blood based on its dielectric spectra. Impedance was measured in flowing blood to prevent aggregation and sedimentation at frequencies between 40 Hz and 110 MHz.

Microfluidic Systems for Blood and Blood Cell Characterization.

A laboratory blood test is vital for assessing a patient's health and disease status. Advances in microfluidic technology have opened the door for on-chip blood analysis. Currently, microfluidic devices can reproduce myriad routine laboratory blood tests.

Temperature Correction to Enhance Blood Glucose Monitoring Accuracy Using Electrical Impedance Spectroscopy.

Electrical methods are among the primarily studied non-invasive glucose measurement techniques; however, various factors affect the accuracy of the sensors used. Of these, the temperature is a critical factor; hence, the effects of temperature on the electrical properties of blood components are investigated in this study. Furthermore, the changes in the electrical properties of blood according to the glucose level are corrected by considering the effects of temperature on the electrical properties.

Electrochemical Impedance Characterization of Blood Cell Suspensions-Part 2: Three-Phase Systems With Single-Shelled Particles.

The analyses presented in Part 1 are expanded to three-phase composite materials. The theory developed in Part 1 is used for analytical and numerical calculations of dielectric spectra. In this study, three-phase systems with single-shelled particles were considered.

Electrochemical Impedance Characterization of Blood Cell Suspensions. Part 1: Basic Theory and Application to Two-Phase Systems.

Electrochemical impedance spectra of composite materials contain information on the topological arrangement, volume fraction, and shape of particles, as well as the dielectric properties of the matrix and particles. The objective of this study is to investigate how these parameters affect the dielectric spectrum and what reliable information can be extracted from experimental data. The main attention was focused on systems with dielectric behavior similar to that of human blood.

A physiometer for simultaneous measurement of whole blood viscosity and its determinants: hematocrit and red blood cell deformability.

In this study, a microfluidic-based physiometer capable of measuring whole blood viscosity, hematocrit, and red blood cell (RBC) deformability on a chip is introduced. The physiometer consists of two major parts: a hydrodynamic component for whole blood viscosity measurement and an electronic component for hematocrit and RBC deformability measurement. In the hydrodynamic component, the whole blood is infused with phosphate buffered saline as a reference fluid for estimation of the whole blood viscosity.

Effects of Aggregation on Blood Sedimentation and Conductivity.

The erythrocyte sedimentation rate (ESR) test has been used for over a century. The Westergren method is routinely used in a variety of clinics. However, the mechanism of erythrocyte sedimentation remains unclear, and the 60 min required for the test seems excessive.

Universal curves for the van der Waals interaction between single-walled carbon nanotubes.

We report very simple and accurate algebraic expressions for the van der Waals (VDW) potentials and the forces between two parallel and crossed carbon nanotubes. The Lennard-Jones potential for two carbon atoms and the method of the smeared-out approximation suggested by Girifalco were used. It is found that the interaction between parallel and crossed tubes is described by two universal curves for parallel and crossed configurations that do not depend on the van der Waals constants, the angle between tubes, and the surface density of atoms and their nature but only on the dimensionless distance.

Van der Waals interaction between two crossed carbon nanotubes.

The analytical expressions for the van der Waals potential energy and force between two crossed carbon nanotubes are presented. The Lennard-Jones potential between pairs of carbon atoms and the smeared-out approximation suggested by L. A.

Field enhancement factor and field emission from a hemi-ellipsoidal metallic needle.

We present an exact solution for the electrostatic field between a metallic hemi-ellipsoidal needle on a plate (as a cathode) and a flat anode. The basic idea is to replace the cathode by a linearly charged thread in a uniform electric field and to use a set of "image" charges to reproduce the anode. We calculate the field enhancement factor on the needle surface and ponderomotive force acting on the needle.