Phase Space Analysis of Cardiac Spectra

Cardiac diseases are one of the main reasons of mortality in modern, industrialized societies, and they cause high expenses in public health systems. Therefore, it is important to develop analytical methods to improve cardiac diagnostics. Electric activity of heart was first modeled by using a set of nonlinear differential equations. Latter, variations of cardiac spectra originated from deterministic dynamics are investigated. Analyzing the power spectra of a normal human heart presents His-Purkinje network, possessing a fractal like structure. Phase space trajectories are extracted from the time series graph of ECG. Lower values of fractal dimension, D indicate dynamics that are more coherent. If D has non-integer values greater than two when the system becomes chaotic or strange attractor. Recently, the development of a fast and robust method, which can be applied to multichannel physiologic signals, was reported. This manuscript investigates two different ECG systems produced from normal and abnormal human hearts to introduce an auxiliary phase space method in conjunction with ECG signals for diagnoses of heart diseases. Here, the data for each person includes two signals based on V_4 and modified lead III (MLIII) respectively. Fractal analysis method is employed on the trajectories constructed in phase space, from which the fractal dimension D is obtained using the box counting method. It is observed that, MLIII signals have larger D values than the first signals (V_4), predicting more randomness yet more information. The lowest value of D (1.708) indicates the perfect oscillation of the normal heart and the highest value of D (1.863) presents the randomness of the abnormal heart. Our significant finding is that the phase space picture presents the distribution of the peak heights from the ECG spectra, giving valuable information about heart activities in conjunction with ECG.Comment: 10 pages, 8 figures, 1 table. arXiv admin note: text overlap with arXiv:2305.1045

Critical behavior of thermal phase transitions of iota-carrageenan in CaCl(2) solution

In situ photon transmission method was applied to study thermal phase transitions of t-carrageenan in CaCl(2) solution. Coil-to-helix (c-h) and helix-to-dimer (h-d) transitions were detected upon cooling. An extra dimer-to-dimer (d-d) transition was observed as well during cooling at low-temperature region. Upon heating only dimer-to-helix (d-h) and helix-to-coil (h-c) transitions were detected. Photon transmission intensity, I(tr) was monitored against temperature to determine several phase transitions and transition temperatures. It was observed that the c-h transition in i-carrageenan-CaCl(2) system performs a crossover between 3D percolation to classical theory. Upon heating, the specific heat exponent over the d-h transition was extracted from the transmitted intensity data and was found to be 0.045. (c) 2005 Elsevier B.V. All rights reserved

PAAm-Kappa Carrageenan Composites: Drying and Swelling with Various Kappa Carrageenan Contents

The purpose of this study is to discuss the role of kappa-carrageenan (kappa-car) in the drying and swelling of polyacrylamide (PAAm)-kappa-car composite. The fluorescence intensity of pyranine increased and decreased as drying and swelling time were increased respectively for all samples. The desorption coefficient, D-d, decreased as kappa-car contents were increased for a given temperature during drying. However, cooperative diffusion coefficient, D-s, increased as kappa-car contents were increased during swelling at a given temperature

Temperature Effect on the Swelling of PAAm-kappa-carrageenan Composites

The steady-state fluorescence (SSF) technique was used for studying swelling of disc-shaped polyacrylamide (PAAm)-kappa-carrageenan (kappa C) composites which were prepared by free-radical crosslinking copolymerization at 80 degrees C. Pyranine was introduced as a fluorescence probe during polymerization. Swelling experiments were performed in water at various temperatures by real-time monitoring of the pyranine (Py) fluorescence intensity, I which decreased as swelling proceeded. Stern-Volmer equation is modified for low quenching efficiencies to interpret the behavior of Py intensity during the swelling of PAAm-kappa C composites. The Li-Tanaka equation was used to determine the swelling time constants, tau(1), and cooperative diffusion coefficients, D(0), from fluorescence intensity, weight, and volume variations of the composites at various temperatures. It was observed that tau(1) first decreased up to 40 degrees C and then increased; naturally, D0 increased up to 40 degrees C and then decrease for all kappa C content gels. Swelling activation energies, DE, were measured for the swelling composites, which are found to be exothermic and endothermic in between 30-40 and 40-60 degrees C, respectively. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1746-1754, 201

Film formation from nano-sized polystyrene latex particles

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Fractal dimensions of kappa-carrageenan gels during gelation and swelling

A photon scattering technique for research on the sol-gel and gel-sol transitions in kappa-carrageenan-water systems with various carrageenan contents (CC) was utilized for characterizing the fractal dimensions during gelation and swelling. It was observed that the scattered photon intensity, I-sc, increased at all temperatures with an increase in the CC when I-sc was monitored against temperature. Additionally, the sol-gel transition temperatures were found to be much lower than the gel-sol transition temperatures, causing hysteresis of the phase transition loops. I-sc increased with an increase in CC at all test temperatures, which is attributed to the formation of a fractal-like carrageenan gel. After drying, the gels were used in swelling experiments where the gels were immersed in water at room temperature, reswelling to the original structure. It was observed that I-sc from the carrageenan gels increased as the CC was increased. The fractal dimension, d, during gelation was found to increase as the gelation temperature was increased. On the other hand, the d values during swelling decreased as the swelling time was increased

Group behaviour in physical, chemical and biological systems

Groups exhibit properties that either are not perceived to exist, or perhaps cannot exist, at the individual level. Such `emergent' properties depend on how individuals interact, both among themselves and with their surroundings. The world of everyday objects consists of material entities. These are, ultimately, groups of elementary particles that organize themselves into atoms and molecules, occupy space, and so on. It turns out that an explanation of even the most commonplace features of this world requires relativistic quantum field theory and the fact that Planck's constant is discrete, not zero. Groups of molecules in solution, in particular polymers ('sols'), can form viscous clusters that behave like elastic solids ('gels'). Sol-gel transitions are examples of cooperative phenomena. Their occurrence is explained by modelling the statistics of inter-unit interactions: the likelihood of either state varies sharply as a critical parameter crosses a threshold value. Group behaviour among cells or organisms is often heritable and therefore can evolve. This permits an additional, typically biological, explanation for it in terms of reproductive advantage, whether of the individual or of the group. There is no general agreement on the appropriate explanatory framework for understanding group-level phenomena in biology