Jianzhong Wu

Learn More
Raman and surface-enhanced Raman scattering (SERS) spectra of calf thymus DNA were investigated. We have carried out improvements to the silver colloid preparation method of Lee and Meisel in two respects. In one method, the silver sol was boiled with rapid stirring for over two hours. In the second method, the silver sol was concentrated by centrifugation(More)
Proteins fold in a confined space not only in vivo, i.e., folding assisted by molecular chaperons and chaperonins in a crowded cellular medium, but also in vitro as in production of recombinant proteins. Despite extensive work on protein folding in bulk, little is known about how and to what extent the thermodynamics and kinetics of protein folding are(More)
Electrostatic interactions may promote or abate polyelectrolyte adsorption onto a charged surface depending on a number of interrelated factors including the surface and polymer charge densities, the salt concentration, and nonelectrostatic interactions such as van der Waals and hydrophobic forces. Even without the nonelectrostatic interactions, the(More)
We use nanoparticle-polymer composites to demonstrate the anti-icing capability of superhydrophobic surfaces and report direct experimental evidence that such surfaces are able to prevent ice formation upon impact of supercooled water both in laboratory conditions and in natural environments. We find that the anti-icing capability of these composites(More)
A new density functional theory is developed for inhomogeneous mixtures of polymeric fluids by combining Rosenfeld’s fundamental-measure theory for excluded volume effects with Wertheim’s first-order thermodynamic perturbation theory for chain connectivity. With no adjustable parameters, theoretical predictions are in excellent agreement with Monte Carlo(More)
A density-functional theory is proposed to describe the density profiles of small ions around an isolated colloidal particle in the framework of the restricted primitive model where the small ions have uniform size and the solvent is represented by a dielectric continuum. The excess Helmholtz energy functional is derived from a modified fundamental measure(More)
While the knowledge of protein folding in a dilute solution is now well-advanced, little is known of the influence of surrounding conditions on the folding kinetics, in particular when the protein is in a dynamically responsive environment. Here we report a new procedure to control the pathways of protein folding by using a thermally responsive polymer that(More)
Herein we report a new strategy for protein refolding by taking advantage of the unique surface and pore characteristics of ethylene-bridged periodic mesoporous organosilica (PMO), which can effectively entrap unfolded proteins and assist refolding by controlled release into the refolding buffer. Hen egg white lysozyme was used as a model protein to(More)
The Percus’ test-particle method is extended to predict the interand intramolecular correlation functions of polymeric fluids using a density functional theory developed earlier @J. Chem. Phys. 117, 2368 ~2002!#. The calculated interand intramolecular distribution functions as well as the site–site correlation functions agree well with the results from(More)
A simple, sensitive, and specific gas chromatographic (GC) method was developed to determine the main bioactive sesquiterpene lactones, trilobolide-6-O-isobutyrates A and B (TBO-A and TBO-B), in Wedelia trilobata, a useful folk herb. A commercially available HP-5 capillary column (30 m x 0.25 mm i.d. x 0.25 microm) was utilized for the direct determination(More)