Prof. Lei Han TANG

Dr. Lei-Han Tang completed his PhD in statistical physics at the Carnegie Mellon University in 1987. He did postdoctoral work on nonequilibrium and disordered systems at various US and German institutions including Texas A&M University, the IFF at KFA Jülich and the Institute for Theoretical Physics at the University of Cologne. He served as Lecturer at the Imperial College London from 1996-1997 before joining the Hong Kong Baptist University as an Associate Professor in 1997 and then full Professor in 2005. His research combines analytical and computational approaches to explore the effects of equilibrium and nonequilibrium fluctuations in various physical and biophysical contexts. In recent years, he has collaborated with experimentalists on the development of quantitative tools and models to analyze and integrate biological data and behavior at the cellular level, in particular those related to metabolism, cell motility, and development. He has also developed formalisms that integrate complex behavior of individuals with communication and feedbacks at the population level to explain collective phenomena such as oscillations and outbreaks. He has published more than 90 articles in physics and biological physics, including 20 in the Physical Review Letters. He has been an active researcher and facilitator of interdisciplinary study of living systems. He was elected Fellow of the American Physical Society in 2010 and served as a member of the IUPAP C3 Commission on Statistical Physics (2014-2020). He is the Director of the Institute of Computational and Theoretical Studies at HKBU.

Project Highlights

1. Emergence of collective oscillations in adaptive cells

 

Spontaneous oscillations in a communicating cell population.

A. An example of chemical oscillations where cells sense and secrete a signaling molecule that mediates cell-to-cell communication.

B. In adaptive response, intracellular activities boost transiently under a stimulus ramp but return to normal level when the signal stabilizes. Such behavior typically involves active processes that consume ATP.

C. Our work establishes a rigorous mathematical relation between adaptive response and phase-leading behavior in intracellular activity at low frequencies, which underlies spontaneous collective oscillations in diverse biological contexts, including starved social amoeba (D. discoideum), yeast suspensions, and otoacoustic emissions from the human ear.

2. Calibrated Intervention and Containment of the COVID-19 Pandemic

 

Early development of COVID-19 outbreaks and containment. a. Daily confirmed cases in Hubei province since the Wuhan lockdown on 23 January, 2020, showing three phases of epidemic development. A daily growth rate of 0.3/day is observed during the initial outbreak (Phase I). b. Data for the rest of China. Early control measures significantly shortened phase II. c. d. Countries in Asia and Europe went through similar stages of pandemic development, but the duration of each phase varied greatly. Mathematical analysis of a model we developed, with parameters calibrated against clinical data, offers a quantitative explanation of the observed behaviour.