Hongliang Xu, Ph.D. EDUCATION 

MAILING
ADDRESS: HauptmanWoodward Medical Research Institute 700 Ellicott Street Buffalo, NY 142031102 
CONTACT INFORMATION: Tel: 7168783443 Email: xuh@buffalostate.edu Email: xu@hwi.buffalo.edu 

Research Interests Mathematical and computational crystallography My research interests lie in the area of mathematical biology, especially the development of novel mathematical models and optimal procedures for determining threedimensional crystal structures from Xray and neutron diffraction data. The socalled “phase problem” in crystallography is the problem of determining the phase angles of the diffracted rays. The phase information, which is lost in the diffraction experiment, is in fact recoverable from the measurable intensities alone. The methods devised to solve the phase problem are known as direct methods. Mathematical Models for Crystallographic Phase Problem In the minimal principle method, the crystallographic phase problem is formulated as a problem of constrained global optimization. Traditionally, a probabilistic model is used to derive the socalled cosine minimal function that plays a pivotal role for determining threedimensional structures. We have recently established a novel statistical model and corresponding statistical minimal function based on the empirical distributions of the structure invariants. This statistical function serves as the foundation of an optimization procedure called statistical ShakeandBake. Favorable applications of this procedure have shown the overall improvement over the existing procedures. Optimal Procedures for Crystallographic Computing Crystallographic computing is one of the areas that would benefit greatly from mathematical optimization. In collaboration with Prof. Nikolaos Sahinidis (Univ. of Illinois), we are currently investigating novel procedures that combine the necessary complementary backgrounds from mathematical optimization and macromolecular crystallography. Specifically, we are developing mathematical optimization algorithms to solve the crystallographic phase problem in a reliable and efficient way. This work promises to lay the foundations of a new generation of crystallographic computing systems that will reveal structures important in the understanding of life, material science, and drug design. Selected Publications


700 Ellicott Street Buffalo, New York 142031102 Tel: 716 898 8600 Fax: 716 898 8660 