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Properties of Proton Transfer in Hydrogen-Bonded Systems at Finite Temperature

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Communications in Theoretical Physics 2002年第10期38卷 407-414页

作者： pang xiao-feng Institute of Life Science and Technology University of Electronic Science and Technology Chengdu 610054 China International Center for Materials Physics the Chinese Academy of Sciences Shenyang 110015 China CCAST (World Laboratory) P.O. Box 8730 Beijing 100080 China

The properties of proton transfer along hydrogen-bonded molecular systems are studied at finite temperature. The dynamic equations of the proton transport along the systems are obtained by using a completely quantummechanics method. From the dynamic equations and its soliton solutions we find out specific heat arising from the motionof solitons in the systems with finite temperature and the critical temperature of the soliton in the protein molecules,which is about 318 K. This shows that we can continuously study some biological phenomena in the living systems bythis model.

关键词： proton transfer, hydrogen bond, critical temperature, specific heat

Influences of Structure Disorder and Temperature on Properties of Proton Conductivity in Hydrogen-Bond Molecular Systems

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Communications in Theoretical Physics 2007年第2期47卷 235-243页

作者： pang xiao-feng YU Jia-feng Institute of Life Science and Technology University of Electronic Science and Technology Chengdu 610054 China International Centre for Materials Physics the Chinese Academy of Sciences Shenyang 110015 China

The dynamic properties of proton conductivity along hydrogen-bonded molecular systems, for example, ice crystal, with structure disorder or damping and finite temperatures exposed in an externally applied electric-field have been numerically studied by Runge-Kutta way in our soliton model. The results obtained show that the proton-soliton is very robust against the structure disorder including the fluctuation of the force constant and disorder in the sequence of masses and thermal perturbation and damping of medium, the velocity of its conductivity increases with increasing of the externally applied electric-field and decreasing of the damping coefficient of medium, but the proton-soliton disperses for quite great fluctuation of the ＂force constant and damping coefficient. In the numerical simulation we find that the proton-soliton in our model is thermally stable in a large region of temperature of T ≤ 273 K under influences of damping and externally applied electric-field in ice crvstal. This shows that our model is available and appropriate to ice.

关键词： proton conductivity structure disorder temperature hydrogen bonded system

Features of Motion of Soliton Transported Bio-energy in Aperiodic α-Helix ProteinMolecules with Three Channels

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Communications in Theoretical Physics 2009年第1期51卷 170-180页

作者： pang xiao-feng LIU Mei-Jie Institute of High-Energy Electronics University of Electronic Science and Technology of China Chengdu 610065 China International Center for Materials Physics Chinese Academy of Sciences Shenyang 110015 China

The structure aperiodicities can influence seriously the features of motion of soliton excited in the α-helix protein molecules with three channels. We study the influence of structure aperiodicities on the features of the soliton in the improved model by numerical simulation and Runge-Kulta method. The results obtained show that the new soliton is very robust against the structure aperiodieities including large disorder in the sequence of mass of the amino acids and fluctuations of spring constant, coupling constant, dipole-dipole interactional constant, ground state energy and chain-chain interaction. However, very strong structure aperiodieities can also destroy the stability of the soliton in the α-helix protein molecules.

关键词： structure aperiodicity soliton stability protein bio-energy Runge-Kulta method

Bio-energy in s-Helix Protein Molecules with Three Properties of Soliton-Transported Channels

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Communications in Theoretical Physics 2007年第2X期48卷 369-376页

作者： pang xiao-feng LIU Mei-Jie Institute of Life Science and Technology University of Electronic Science and Technology of China Chengdu 610054 China International Center for Material Physics the Chinese Academy of Sciences Shenyang 110015 China

We study numerically the propagating properties of soliton-transported bio-energy excited in the a-helix protein molecules with three channels in the cases of the short-time and long-time motions and its features of collision at temperature T = 0 and biological temperature T = 300 K by the dynamic equations in the improved Davydov theory and fourth-order Runge-Kutta method, respectively. From these simulation experiments we see that the new solitons in the improved model can move without dispersion at a constant speed retaining its shape and energy in the cases of motion of both short-time or T = 0 and long time or T = 300 K and can go through each other without scattering in their collisions. In these cases its lifetime is, at least, 120 ps at 300 K, in which the soliton can travel over about 700 amino acid residues. This result is consistent with analytic result obtained by quantum perturbed theory in this model. In the meanwhile, the influences of structure disorder of a-helix protein molecules, including the inhomogeneous distribution of amino acids with different masses and fluctuations of spring constant, dipole-dipole interaction, exciton-phonon coupling constant and diagonal disorder, on the solitons are also studied by the fourth-order Runge-Kutta method. The results show that the soliton still is very robust against the structure disorders and thermal perturbation of proteins at biological temperature 300 K. Therefore we can conclude that the new soliton in the a-helix protein molecules with three channels is a possible carrier of bio-energy transport and the improved model is possibly a candidate for the mechanism of this transport.

关键词： bio-energy transport soliton protein molecule Runge-Kutta method thermal stabilization

Calculation of Vibrational Energy Spectra of H_(2)O Molecule by Nonlinear Quantum Theory

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Chinese Physics Letters 1996年第9期13卷 660-663页

作者： CHEN Xiang-rong GOU Qing-quan pang xiao-feng Institute of Atomic and Molecular Science at High Temperature and High Pressure Sichuan Union UniversityChengdu 610065

The vibrational energy spectra of OH stretch of H_(2)O in both vapour and liquid phases are calculated by using the quantized discrete self-trapping equation of nonlinear quantum *** results obtained are in good agreement with the ***,it is noted that the behaviour of the distribution of energy levels of high excited states obtained here is useful in optical spectrum research.

关键词： theory vapour vibrational

Dynamic Properties of Proton Transfer in the Anharmonic-Interaction Hydrogen Bond Systems

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Communications in Theoretical Physics 2001年第5期35卷 615-620页

作者： Yan Xun-Ling Dong Rui-Xin pang xiao-feng Department of Physics Liaocheng Teacher"s College Institute of High-Energy Electronics University of Electronic Science and Technology of China

We analyze the properties of the excited solitary-wave model in the case of anharmonic-interaction of heavy ionic lattice in hydrogen bond *** this case,some new phenomena *** find different types of solutions for the proton displacement and influences on the kinks and pulse solitary waves by numerical *** each of them we have presented a direct relation with the effective potential of the system.

关键词：氢原子束缚系统非简谐相互作用孤子波

Stochastic Resonance in a Bistable System Subject to Dichotomous Noise

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Communications in Theoretical Physics 2008年第8期50卷 387-390页

作者： ZHOU Yu-Rong PAN Hui-Mei GUO feng pang xiao-feng School of Life Science and Technology University of Electronic Science and Technology of China Chengdu 610054 China School of Information and Electric Engineering Panzhihua University Panzhihua 617000 China School of Automation Engineering University of Electronic Science and Technology of China Chengdu 610054 China

The stochastic resonance phenomenon in a bistable system subject to Markov dichotomous noise （DN） is investigated. Based on the adiabatic elimination and the two-state theories, the explicit expressions for the signal-tonoise ratio （SNR） and the spectral power amplification （SPA） have been obtained. It is shown that two peaks can occur on the curve of SNR versus the intensity of the DN. Moreover, the SNR is a non-monotonic function of the correlation time of the DN. The SPA varies non-monotonously with the strength of the DN. The dependence of the SNR on the frequency and the amplitude of the external periodic signal are discussed. The effect of the external frequency and the correlation time of the DN on the SPA are analyzed.

关键词： stochastic resonance signal-to-noise ratio spectral power amplification

Altered Expression of Matrix Metalloproteinases and Tight Junction Proteins in Rats following PEMF-Induced BBB Permeability Change

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Biomedical and Environmental Sciences 2012年第2期25卷 197-202页

作者： ZHANG Ya Mei ZHOU Yan QIU Lian Bo DING Gui Rong pang xiao feng School of Life Science and Technology University of Electronic Science and Technology of China Chengdu 610054 Sichuan China Department of Radiation Medicine Faculty of Preventive Medicine Fourth Military Medical University Xi＇ an 710032 Shanxi China

Objective To investigate the expression of occludin,ZO‐1,MMP‐2,and MMP‐9 in cerebral microvasculature following Pulse Electromagnetic Field（PEMF） induced BBB permeability *** Sprague‐Dawley rats were randomized into PEMF and sham exposed groups（n=8）.After exposure to PEMF at 0.5,1,3,6,and 12 h,BBB permeability was measured by Evans‐Blue *** expression of occludin,ZO‐1,MMP‐2,and MMP‐9 were detected by real‐time quantitative reverse transcriptase PCR and western ***‐2 and MMP‐9 activity were detected by EnzChek gelatinase *** Compared with the sham group,PEMF exposure led to increased permeability of the BBB to EB,which was prolonged after *** permeability became progressively more severe,and recovered at 6 *** gene and protein expression of occludin and ZO‐1 were significantly decreased,while MMP‐2 and MMP‐9 expression were significantly increased after exposure to *** levels of expression recovered 12 h following *** Changes to BBB permeability were related to the alteration expression of tight junction proteins and matrix metalloproteinase after exposure to PEMF.

关键词： Pulse electromagnetic field Blood-brain barrier Cerebral microvasculature

Investigation on Molecular Mechanism Cured Sickness for Infrared medical-Instrument

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Chinese Journal of Biomedical Engineering(English Edition) 1999年第3期8卷 39-40页

作者： pang xiao-feng Bioengineering Program and Automation Dept University of Electronic Science andTechnology of China. Chengdu 610054- Sichuan PR.China