Biomedical subjects

K Y Szeto

Publications and source records attributed to K Y Szeto.

4 recordsLinked to original sources

PubMed2006

Linear relation on the correlation in complex networks.

Correlation in complex networks follows a linear relation between the degree of a node and the total degrees of its neighbors for six different classes of real networks. This general linear relation is an extension of the Aboav-Weaire law in two-dimensional cellular structures and provides a simple and different perspective on the correlation in complex networks, which is complementary to an existing description using Pearson correlation coefficients and a power law fit. Analytical expression for this linear relation for three standard models of complex networks: the Erdos-Renyi, Watts-Strogatz, and Barabasi-Albert networks is provided. The slope and intercept of this linear relation are described by a single parameter a together with the first and second moment of the degree distribution of the network. The assortivity of the network can be related to the sign of the intercept.

Journal Article↗

PubMed2004

Damage spreading on two-dimensional trivalent structures with Glauber dynamics: hierarchical and random lattices.

The damage spreading of the Ising model on various two-dimensional trivalent structures with Glauber dynamics is investigated. It is shown that topology plays an important role in determining the damage spreading transition temperatures of the trivalent structures. When damage is considered in terms of only the topological properties of the cellular patterns, the transition temperature above which damage is saturated is found to be determined by the cells with the highest edge number. When the area of cells is also taken into account in the computation of damage, the damage spreading transition temperatures are all lowered. These results are verified by simulation on a set of hierarchical lattices constructed by recursive application of the star-triangle transformation on the vertices of the hexagonal structure, as well as soap froth and randomized lattice structures using Voronoi construction.

Journal Article↗

PubMed2002

Universal topological properties of two-dimensional trivalent cellular patterns.

Universal topological properties of two-dimensional trivalent cellular patterns are found from shell analysis of soap froth and computer-generated Voronoi diagrams. We introduce a cluster analysis based on the shell model and find the universal relation ln(a/mu(2)) = A+Bln(mu(2)), with the generalized Aboav parameter a and second moment of the number of cell edge distribution mu(2). For the second, third, and fourth shells of the cluster, A and B are the same for all samples. Furthermore, A is increasing with shell number while B is a universal number, -0.90. For the first shell, the slope B is the same for soap froths, but slightly different from Voronoi graphs.

Cells↗

PubMed2001

Interactions of bismuth with human lactoferrin and recognition of the Bi(III)-lactoferrin complex by intestinal cells.

Several bismuth compounds are currently used as antiulcer drugs, but the mechanism of action still remains unclear. The antimicrobial activity of Bi(III) complexes toward Gram-negative bacteria is reported to be dependent on the iron uptake system [Domenico, P., et al. (1996) J. Antimicrob. Chemother. 38, 1031-1040]. Electronic absorption and 13C NMR spectroscopic data show that Bi(III) binds to human lactoferrin at the specific Fe(III) sites along with either carbonate or oxalate as the synergistic anion. The uptake of Bi(III) by apo-hLF was rapid [minutes in 10 mM Hepes buffer and 5 mM bicarbonate (pH 7.4)], and almost equal in both lobes. The presence of ATP facilitates the release of Bi(III) from the Bi2-hLF complex when the pH is lowered. The Bi2-hLF complex blocked the uptake of the radiolabeled 59Fe-hLF complex into rat IEC-6 cells. Surprisingly, apo-hLF (but not apotransferrin) was almost as effective in blocking 59Fe uptake as bismuth-loaded lactoferrin. These results suggest that Bi(III)-loaded hLF might be recognized by the lactoferrin receptor and be taken up into cells.

Adenosine Triphosphate↗