RESUMO
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.
Assuntos
Bentonita/química , Metais Pesados/isolamento & purificação , Nanocompostos/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Metais Pesados/químicaRESUMO
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.
RESUMO
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.