Genetic polymorphisms of cytochrome P450 enzymes 2C9 and 2C19 in a healthy Mongolian population in China

We examined the distribution of major allelic variants of CYP2C9 and CYP2C19 in the Mongolian population of China and compared it with that of other populations. The polymorphisms of CYP2C9 (including the CYP2C9*1, CYP2C9*2 and CYP2C9*3 alleles) and CYP2C19 (including the CYP2C19*1, CYP2C19*2 and CYP2C19*3 alleles) were analyzed in 280 healthy unrelated Chinese Mongolian subjects, using a PCR-RFLP assay. The frequencies of CYP2C9*1, *2 and *3 alleles were 0.97, 0.00 and 0.03, respectively. The frequencies of CYP2C19*1, *2 and *3 alleles were 0.72, 0.24 and 0.04, respectively. We did not find any differences in the allelic distribution of these two genes between age groups. However, the genotype frequency of CYP2C9 *1/*3 was significantly higher in males than in females. Compared with other populations, we found that the allele frequencies of the CYP2C9*2 and CYP2C9*3 allelic variants in this Mongolian population of China were similar to those reported for other Asian populations, with significant differences compared to Caucasians and African-Americans

First-principles studies of lithium adsorption and diffusion on graphene with grain boundaries

To understand the effect of topological defects on the Li adsorption on graphene, we have performed first-principles calculations to study the adsorption and diffusion of a lithium adatom on graphene with (5, 0)|(3, 3), (2, 1)|(2, 1), and (2, 0)|(2, 0) grain boundaries (GBs). Our results show that the adsorption of a Li adatom on defect-free graphene is endothermic with respect to the bulk Li and the adsorption of a Li adatom on the GBs of graphene is exothermic. In particular, the presence of a (2, 0)|(2, 0) GB leads to a decrease of about 0.92 eV in the adsorption energy of a Li adatom on graphene. This suggests that GBs would significantly enhance the Li adsorption on graphene. In three cases of GBs, the energy barrier for the diffusion of a Li adatom along the boundary is lower than that perpendicular to the boundary, indicating that a Li adatom tends to diffuse along the boundary and to migrate from nonboundary sites toward the boundary zone. The difference charge density and the Bader charge analysis both show there is a significant charge transfer from the Li adatom to its nearest neighboring carbon atoms