Volume 1 Issue 1
Authors: Jordi Marcé-Nogué
Abstract: In order to contribute to the study of the Helical Myocardial Ventricular Band, a computational model to simulate the behaviour of the myocardial tissue, mainly based in the fibres, is presented. It is based in considering the path described by the band as a preferential path described by fibres, and in considering that the propagation of the electromechanical activation follows this path. The model describes two basic aspects of the myocardial tissue: an active part that generates the contraction and a passive part due to the connective tissue. Interaction of these parts generates governing equation. The simulation of the model is based on generating a propagation of electrical stimulus that follows the preferential path described by the band. As a consequence of the application of it, a deformation following the same path of the stimulus is obtained. The results obtained in the computational are compared with others works in literature with real hearts to conclude that, if the electro-mechanical activation sequence in the myocardium coincides with the path described by the HMVB the path and the delay observed in the shortening of the fibres are according with the expected and observed behaviour in real hearts.
Keywords: Myocardium; Electro-mechanical Activation; Helical Ventricular Myocardial Band; Computational Model; Fibres
Authors: Md. Yahia Hussain; Roger E. Khayat
Abstract: The upstream flow near the exit of a channel for steady-state moderately inertial jet emerging from the channel is examined theoretically in this study. Poiseuille flow conditions are assumed to prevail far upstream from the exit. The problem is reduced to an eigenvalue problem governing the departure from Poiseuille flow. This is shown to be on the order of the inverse Reynolds number. The study complements Tillett’s asymptotic analysis on free surface jet flow, focusing on the flow upstream from the channel exit particularly the region near the wall. Numerical calculations based on FLUENT are used for comparison, which illustrate the difficulty of conventional numerical methodologies to accurately capture the flow near the singularity, and the need for the current local asymptotic analysis.
Keywords: Free-surface Jet; Moderate Reynolds Number; Exit Singularity; Upstream Flow; Asymptotic Matching
Authors: Miuta Carmina Rau; Doina Costandache; Octavian Baltag
Abstract: The paper presents a complex installation destined to biomagnetic researches. The structure of the installation consisting of a shielded aluminum room, coil systems for the control of the surrounding magnetic field components and a SQUID HTS gradiometer is described. The performances of the realized installations allowed us to register for the first time in Romania a biomagnetic signal generated by the cardiac activity.
Keywords: Biomagnetometry; Biomagnetism; Helmholtz Coils; Active Compensation; Shielded Room
Authors: Jinniu Hu; Hiroshi Toki; Wu Wen; Hong Shen
Abstract: The properties of neutron matter is studied in the Hartree-Fock theory with a bare meson-exchange nucleon-nucleon interaction and Urbana IX three-body interaction. We find that the energy contribution from tensor interaction is very small in neutron matter, which consists of only the two-body isospin triplet channel ( ). The strong repulsive interaction between two nucleons in the short distance is treated by unitary correlation operator method (UCOM). The equation of state (EOS) in our calculation only with the Bonn potential agrees with the one of AV18 potential including the relativistic boost effect in the variational method for neutron matter. The three-body interaction is also introduced in this framework to improve the properties of neutron matter in higher density region.
Keywords: Hartree-Fock; Neutron Matter; UCOM; Three-body Interaction
Authors: M. M. Asimov; R. M. Asimov; A. N. Rubinov; A. I. Gisbrecht
Abstract: The results in vivo investigation biophotonics of laser-induced photodissociation of oxyhemoglobin in cutaneous blood vessels and its role in biomedical processes are presented. New method for determination of an individual response to the effect of laser radiation is presented. It is shown that, in order to make the methods of phototherapy as well as laser therapy really efficient, one has to control the oxygen concentration in tissue to keep it at the necessary level. A novel method of optical "dosimetry" based on the use of changes in oxygen concentration in tissue as a feedback signal for optimization of the therapeutic effect of low intensity laser radiation has been developed.
Keywords: Hemoglobin; Oxyhemoglobin; Tissue Oxygenation; Hypoxia; Phototherapy; Photodissociation