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Dr Henggui Zhang Reader Biological Physics Group, School of Physics & Astronomy |
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Office: Telephone: Fax: Email: |
Room 3.07, (0161) 306 3966 (0161) 306 3941 |
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Downloadable Source Codes for
Cardiac Modelling
1) I(Kr) rectification and action potential/QT interval duration
2) Models of Action Potentials for Rabbit Sinoatrial Node Cells
3) Models of Effects of ACh on Action Potentials of Sinoatrial Node Cells
Introduction
In
the last decade, advances in life sciences have gathered a vast amount of
experimental information about biological systems at cellular and sub-cellular
levels. Now we are facing a big challenge: how do we interpret, analyse the
experimental information and relate it to the functions of life? Can we
reconstruct biological systems from such detailed information? There is a
strong motivation behind this. As a biological system is an integral system,
within which components interact with each other. The interaction coordinates
the simple behaviours of a biological system at cellular and sub-cellular
levels into more complicated behaviours at tissue and organ levels. To
understand the functions of a biological system, one has to synthesize the
detailed, but isolated biological information obtained at cellular and
sub-cellular systems into an interactive system at tissue and organ levels.
Recently,
developments in non-linear science, modern physics of excitable medium, applied
mathematics, together with availability of supercomputing power, have provided
powerful tools to integrate detailed biological information into an interactive
system. This forms a new exciting research area – reconstruction of virtual
biological systems: from cell to organ.
Research Interests
My research covers the following areas: Computational Biology, Non-linear Dynamics. Specifically my research fields are:
- Modelling the electrical activity of cardiac cells at single cell level
- Modelling the electrical activity of cardiac systems at tissue and organ levels
- Chaotic time serise analysis and control of chaos
- Spatiotemporal complexity of biological systems
(1) Modelling the electrical activity of cardiac cells at single cell level
The work here is to construct biophysically detailed and accurate models for the electrical activity of cardiac cells, based on the voltage-clamp experimental data. The validaty of the model is to be able to re-generate the experimental observations, both qualitativelly and quantitativelly. Such experimental observations include the characteristics of action potentials, responses to certain ionic channel blockers.
Selected papers:
H Zhang*, A.V.Holden, I.Kodama, H.Honjo, M.Lei, T.Vagues & M.R.Boyett (2000) "Mathematical models of action potentials in the periphery and centre of the rabbit sinoatrial node", Journal of American Physiology (Heart and Circulation), 279(1):H397-H421.
H Zhang*, A.V.Holden,
D.Noble & M.R.Boyett
(2000) "Modelling the chronotropic effects of acetylchonine on the pacemaker activity of sinoatrial node" Journal of Physiology (
H. Zhang*, A.V.Holden, D.Noble & M.R.Boyett "Analysis the chronotropic effects of ACh on the pacemaker activity of rabbit sinoatrial node cells" Submitted to Biophysical Journal, 2000.
H. Zhang*, A.V.Holden and M.R.Boyett (2000). "Computer modelling the sinoatrial node" In: Computer Models of the Heart: Theory and Clinical Application ed Frank B. Sachse and Olaf D, in press.
Z. Li, H. Zhang, A.V.Holden and C.Orchard (2000). "Mathematical modelling of the electrical activity of ventricular cardiac cells: regional differences and propagation" . In: Computer Models of the Heart: Theory and Clinical Application ed Frank B. Sachse and Olaf D, in press.
A. Garny, H. Zhang=, M.R.Boyett, P. Khol, P. Noble & D. Noble (2000) "An advanced computer models of rabbit sinoatruial node cells". Biophysical Journal, 78 No.1 Pt.2 p.P2674.
(2) Modelling the electrical activity of cardiac tissue
The work here is to modelling the integrative behaviours of electrical activity of cardiac cells at the tissue level. Studies include the initiation and propagation of action potentials in the tissue, mechanisms underlying the genesis of cardiac arrhythmias, control of cardiac arrhythmias.
Selected Papers:
H. Zhang*, A.V. Holden and M.R.Boyett (2000). "Gradient versus MOSAIC models of rabbit sinoatrial node" Circulation, in Press
H Zhang*, R.L.Winslow, A.V.Holden (1998) "Re-entrant excitation initiated in models of inhomogeneous atrial tissue" , Journal of Theoretic Biology, Vol.191, No.3, pp.279-287.
H Zhang*, Boyett, M.R., Holden, A.V., Honjo, H. and Kodama, I. (1997) "A computer model of pacemaker shift within the mammalian sinoatrial node" Journal of Physiology, vol.504P, p.P70.
Biktashev, V.N., Holden, A.V., H Zhang (1997) "A model for the action of external current into excitable tissue" International Journal of Bifurcation and Chaos, Vol.7, No. 2: 477-485.
H Zhang*, A.V.Holden, M.R.Boyett (1997) "The pacemaking system of the heart: from coupled oscillators to nonlinear waves", Nonlinear Analysis-Theory Methods & Applications, Vol.30, No.2, pp.1019-1027
H Zhang*, A.V.Holden (1997) "One dimensional modelling the vulnerability to reentry of mammalian atrial tissue", Journal of Theoretic Biology, 184 (2) 119-124.
M.Boyett, A.V.Holden, I.Kodama, R.Suzuki, H. Zhang*. "Vagal control of sino-atrial node - experiments and simulations". Chaos, Soliton & Fractals 5 (1995): 425-438
A.V.Holden, H Zhang*. "Characteristics of atrial re-entry and meander computed from a model of a rabbit single atrial cell" . Journal of Theoretic Biology 175 (1995): 545-551.
(3) Chaotic time serise analysis and control of chaos
Biological systems are nonlinear. Characteristics of signals measured from such systems could be analysized by nonlinear dynamics methods. Such characteristics include the fractal dimension, entropy and Liapunov exponent and persistance of strain.
Selected Papers:
H Zhang*, A.V.Holden. "Estimation of the persistence of strain from a time series as a measure of the geometry of an attractor". Chaos, Solitons & Fractals 2 (1992) 493.
H Zhang*, A.V.Holden, M.Lab, M.Moutoussis. "Estimation of the persistence of strain from experimental recordings from cardiac tissue". Physica 58D (1992) 489-496.
K.Yip, H Zhang. Bifurcation of kidney hemodynamics in hypertension. In: 1992 Lectures in Complex Systems. Eds. L.Nadel, D.Stein, SFI Studies in Sciences of Complexity, Vol. V, Addison-Wesley, 1993, p663-670.
H Zhang*, A.V.Holden. Measuring the complexity of attractors from single and multi-channel EEG signals. In: 1992 Lectures in Complex Systems. Eds. L.Nadel, D.Stein, SFI Studies in Sciences of Complexity, Vol. V, Addison-Wesley, 1993, p671-678.
X. Gong, F.Li, H Zhang* "On the control of chaotic neurons", Chaos, Soliton & Fractls, 7 (1996): 1397-1409
(4) Spatiotemporal complexity
Selected Papers:
A.V.Holden, M.Poole, J.V.Tucker and H Zhang*. "Coupling CMLs and the synchronization of a ultiplayer neural computing system". Chaos, soliton and Fractals 4 (1994): 2249-2268.
A.V.Holden, J.V.Tucker, H Zhang, M.Poole. "Coupled map lattices as computational systems". Chaos 2 (1992) 367-376
A.V.Holden and H Zhang*. "Lyapunov exponent spectrum for a generalised coupled map lattice". Chaos, Solitons & Fractals 2 (1992) 155-164
For cardiac modelling, the computer models have gone beyond simulation, it has come to a stage for prediction. For example, see:
H Zhang*, A.V.Holden, I.Kodama, H. Honjo, M. Lei, Y. Takagishi, M.R.Boyett (1999) "Hypothesis to explain the block zone protecting the sinoatrial node" Biophysics Journal Vol 76, No. 1 Pt2, p.A368.
M.R.Boyett, I.Kodama, M.R.Nikmaram, M.Yamamoto, H.Honjo, R.Niwa, H. Zhang, A.V.Holden (1998) "Regional differences in the role of the rapid delayed rectifier K+ current, I(K,r), within the rabbit sinoatrial node", Journal of Physiology (LONDON), Vol. 511P, p.P7
H Zhang*, Boyett, M.R., Holden, A.V., Honjo, H. and Kodama, I. (1998) "A hypothesis to explain the decline of sinoatrial node function with age", Journal of Physiology, Vol.511P, pp.P76-P
For more details please see the list of my publications.
Autobiography
Born in 1964 in China, I was educated in Physics (BSc,
1985), Computer Science (MSc, 1985-1988), Non-linear Science (Ph.D 1988-1990), and Biomedical Science (Ph.D, 1991-1994). Since 1991, I have been working as a
research assistant (1991-1994, Leeds, funding from MRC), postdoctoral research
fellow (1994 - 1995, JHU, funding from