Adsorption of Heavy Metal Ions from Aqueous Solutions by Bentonite Nanocomposites.

A series of bentonite nanocomposites have been synthesized by modifying bentonite with hexadecyltrimethylammonium bromide (CTMAB) and the common complexing agents, complexone (ethylene diamine tetraacetic acid, EDTA) or mercaptocomplexant (2-Mercaptobenzothiazole, MBT). These adsorbents are used to remove heavy metal ions (Cu(2+), Zn(2+), Mn(2+),Co(2+)). The Bent-CTMAB-MBT adsorbed metal ions are higher than Bent-CTMAB-EDTA under the same ion concentration in AAS. Compared with the single ion system, the adsorption of the mixed ion system of Cu(2+), Zn(2+), Mn(2+), Co(2+) had decreased differently. In the mixed system, the adsorption of Mn(2+) is significantly lower, but the adsorption of Cu(2+) was highest. The adsorption sequence of these four metal ions was Cu(2+) > Zn(2+) > Co(2+) > Mn(2+), and the selective adsorption was closely related to the hydration energy of heavy metal ions. We could remove more metal ions in different stages with the adsorption sequence.

DNA repair gene XRCC3 Thr241Met polymorphism and glioma risk: a meta-analysis.

BACKGROUND: The polymorphism of XRCC3 Thr241Met has been indicated to be correlated with glioma susceptibility, but study results are still debatable. The present meta-analysis was performed to investigate the association between XRCC3 Thr241Met polymorphism and glioma. METHODS: A total of 3754 glioma patients and 4849 controls from nine separate studies were involved. The pooled odds ratio (OR) and its corresponding 95% confidence interval (CI) was assessed by the random-effects model. RESULTS: The association between XRCC3 Thr241Met polymorphism and glioma was significant in the recessive model (OR = 1.36; 95% CI, 1.02 - 1.82; P = 0.03). In a stratified analysis by the ethnicity, significantly increased risk was detected in Asians (OR = 1.93; 95% CI, 1.18 - 3.17; P = 0.009). CONCLUSIONS: In conclusion, XRCC3 Thr241Met polymorphism was implied to be associated with increased glioma risk. More studies are needed to validate this result.

Synthesis and spectroscopic DNA binding studies of [Ru(phen)2(tbtc)]2+ and [Ru(2,9-dmp)2(tbtc)]2+.

A new polypyridyl ligand tbtc (tbtc=4,5,9,14-tetraaza-benzo[b]triphenylene-11-carboxylic acid methyl ester) and its complexes [Ru(phen)2(tbtc)]2+ (1) (phen=1,10-phenanthroline) and [Ru(2,9-dmp)2(tbtc)]2+ (2) (2,9-dmp=2,9-dimethyl-1,10-phenanthroline) were synthesized and characterized by element analysis, MS, and 1H NMR. The DNA binding properties of both complexes to calf thymus DNA (CT-DNA) were investigated by different spectrophotometric methods and viscosity measurements. The results suggest that both complexes bind to DNA via an intercalative mode, and the DNA binding affinity of complex 1 is much greater than that of complex 2. This difference in binding affinity probably was caused by the different ancillary ligands. Also, when irradiated at 365 nm, complex 1 was found to be a more-effective DNA-cleaving agent than complex 2.