Jian-Ping Sang

Fabrication of a regular tripod Ni–P nanorod array and an AAO template with regular branched nanopores using a current-controlled branching method

We present a current-controlled branching method for the fabrication of anodic aluminum oxide (AAO) templates with a triply-branched nanopore structure. By controlling the current density in the branching process, a regular triply-branched nanopore array structure was obtained in the AAO template conveniently and precisely. Based on this template, a regular tripod Ni–P amorphous nanorod array was fabricated by electroless deposition. The present method is particularly advantageous for the fabrication of templates and materials with a complex and accurate multiply branched nanostructure.

Computation and simulation of the structural characteristics of the kidney urea transporter and behaviors of urea transport.

Urea transporters are a family of membrane proteins that transport urea molecules across cell membranes and play important roles in a variety of physiological processes. Although the crystal structure of bacterial urea channel dvUT has been solved, there lacks an understanding of the dynamics of urea transport in dvUT. In this study, by using molecular dynamics simulations, Monte Carlo methods, and the adaptive biasing force approach, we built the equilibrium structure of dvUT, calculated the variation in the free energy of urea, determined the urea-binding sites of dvUT, gained insight into the microscopic process of urea transport, and studied the water permeability in dvUT including the analysis of a water chain in the pore. The strategy used in this work can be applied to studying transport behaviors of other membrane proteins.

Synthesis and photoluminescence properties of the ZnO@SnO2 core–shell nanorod arrays

The ZnO@SnO2 core–shell nanorod arrays have been synthesized. As the cores, ZnO nanorod arrays were first prepared by aqueous chemical growth method. Then using a simple liquid-phase deposition method, SnO2 was deposited on the ZnO nanorod arrays. Scanning electron microscopy, transmission electron microscopy, and X-ray diffraction were used to characterize the morphologies and structures of the products. Photoluminescence properties were also investigated. It was found that the ZnO@SnO2 core–shell nanorod arrays showed enhanced UV and green emissions when compared with the bare ZnO nanorod arrays.

A Three-State Multi-Ion Kinetic Model for Conduction Properties of ClC-0 Chloride Channel

A three-state, multiion kinetic model was proposed to enable the conduction properties of the mammalian channel ClC-0 to be well characterized. Using this rate-theory based model, the current-voltage and conductance-concentration relations were obtained. The five parameters needed were determined by fitting the data of conduction experiments of the wild-type ClC-0 and its K519C mutant. The model was then tested against available calculation and simulation data, and the energy differences between distinct chloride-occupancy states computed agreed with an independent calculation on the binding free energies solved by using the Poisson-Boltzmann equation. The average ion number of conduction and the ion passing duration calculated closely resembled the values obtained from Brownian dynamics simulations. According to the model, the decrease of conductance caused by mutating residue K519 to C519 can be attributed to the effect of K519C mutation on translocation rate constants. Our study sets up a theoretical model for ion permeation and conductance in ClC-0. It provides a starting point for experimentalists to test the three-state model, and would help in understanding the conduction mechanism of ClC-0.

Comparison in structural stability between chain A and B of CLC-ec1 exchanger by using MD simulation

The CLC-type exchangers have been extensively studied in recent years. CLC-ec1, whose crystal structure is known and several experimental and theoretical hot spots have been identified, but the structural stability in true solution environment of this protein has not been provided. In this paper, we analyzed the structural stability of CLC-ec1 protein by using the atomistic molecular dynamics (MD) simulation. The simulation result indicates that there exists no inevitable correlation between chain A and chain B in expressing their biological function. Chain A has smaller average Cα displacement value than that of chain B. The calculated electrostatic binding free energy and its fluctuation of chain A are also smaller. These results indicate that chain A has more stable structure than chain B in physical essence. It is to say that chain A may be more reliable than chain B in expressing their biological function. This work proposes a new topic on future experimental and theoretical investigations for biologists and biophysicists.

Homogeneity of Load Distribution Plays a Key Role in Global Synchronizability of Complex Networks

Many structure parameters have been suggested to predict the synchronizability of complex networks. They were qualitatively suitable for certain networks but failed for others. Based on the coupled oscillator model, we find that the homogeneity of load distribution determines the synchronizability of complex networks, and the standard deviation of edge betweenness centrality is coincident with synchronizability for various complex networks. These results suggest that in order for a network to hence to synchronize more effectively, the load distribution must be more homogeneous.