Biomedical subjects

Muthukumaran Packirisamy

Publications and source records attributed to Muthukumaran Packirisamy.

3 recordsLinked to original sources

PubMed2005

Analysis of diffraction gratings by using an edge element method.

Typically the grating problem is formulated for TE and TM polarizations by using, respectively, the electric and magnetic fields aligned with the grating wall and perpendicular to the plane of incidence, and this leads to a one-field-component problem. For some grating profiles such as metallic gratings with a triangular profile, the prediction of TM polarization by using a standard finite-element method experiences a slower convergence rate, and this reduces the accuracy of the computed results and also introduces a numerical polarization effect. This discrepancy cannot be seen as a simple numerical issue, since it has been observed for different types of numerical methods based on the classical formulation. Hence an alternative formulation is proposed, where the grating problem is modeled by taking the electric field as unknown for TM polarization. The application of this idea to both TE and TM polarizations leads to a two-field-component problem. The purpose of the paper is to propose an edge finite-element method to solve this wave problem. A comparison of the results of the proposed formulation and the classical formulation shows improvement and robustness in the new approach.

Journal Article↗

PubMed2005

Modeling of chemical control of human respiratory system.

This paper addresses the fundamental understanding of the chemical control of respiratory system that would be needed to improve the efficiency of artificial ventilators and implement appropriate controllers. Hence, non-linear model for simulation of chemical control of human respiratory system under different physiological conditions is presented. The paper also presents the non-linear dissociation behaviors for oxygen and carbon dioxide solutions in the blood and the Bohr-Haldane effects as well as a new controller model. Tests were conducted on the model under different conditions such as hypoxia, hypercapnia, hypoventilation, and hyperventilation with some combination tests, in order to verify the validity of the assumptions that were made. Results indicate a very close agreement between the responses obtained from the present model and other published experimental and theoretical results. This model can be used to design a novel artificial respirator controller meeting the bodily requirements of the patient under mechanical ventilation.

Carbon Dioxide↗

PubMedDate not supplied

Bioenzymatic detection of troponin C using micro-opto-electro-mechanical systems.

Diagnosis and monitoring of critical diseases such as acute myocardial infarction (AMI) require a quantitative analysis of biological molecules. A high-throughput identification of these biological molecules can be generated by using micro-electro-mechanical systems (MEMS) structures like simple cantilever beams, which respond to the intermolecular forces resulting from binding these molecules. Biochemical markers like troponin C are considered the primary markers for myocardial injury and have generated considerable interest. A 26-residue lytic membrane protein of bee venom melittin (ME) is chosen to interact with rabbit skeletal muscle troponin C (TnC) on the surface of the cantilever beams. An optical beam deflection method is employed to identify the enzymatic reaction on the surface of the cantilever due to these proteins. Identification of these proteins is also done using fluorescence spectroscopy (FS) to compliment the optical monitored deflection method. A second set of proteins like horse radish peroxide (HRP) and hydrogen peroxide (H2O2) are applied to atomic force microscopy (AFM) cantilever beams to study their behavior under the enzymatic reactions of proteins. Identification of these proteins is done using Fourier transform infrared spectroscopy (FTIR). An analytical model of the cantilever beam is developed, and its mode shapes are studied by employing orthogonal polynomials in the classic Rayleigh-Ritz method. The surface stress caused by the enzymatic reaction of the proteins that leads to pure bending on the top surface of the cantilever is evaluated. The information provided by the experimental and analytical modeling reported in this work will be useful in the development of a portable biosensor for the detection of AMI.

Biosensing Techniques↗