RESUMO
The functional polymorphism Ser326Cys (rs1052133) in the human 8-oxoguanine DNA glycosylase (hOGG1) gene has been implicated in bladder cancer risk. However, reports of this association between the Ser326Cys polymorphism and bladder cancer risk are conflicting. In order to help clarify this relationship, we made a meta-analysis of seven case-control studies, summing 2521 cases and 2408 controls. We used odds ratios (ORs) with 95% confidence intervals (95%CIs) to assess the strength of the association. Overall, no significant association between the hOGG1 Ser326Cys polymorphism and bladder cancer risk was found for Cys/Cys vs Ser/Ser (OR = 1.10, 95%CI = 0.74-1.65), Ser/Cys vs Ser/Ser (OR = 1.07, 95%CI = 0.81-1.42), Cys/Cys + Ser/Cys vs Ser/Ser (OR = 1.08, 95%CI = 0.87-1.33), and Cys/Cys vs Ser/Cys + Ser/Ser (OR = 1.04, 95%CI = 0.65-1.69). Even when stratified by ethnicity, no significant association was observed. We concluded that the hOGG1 Ser326Cys polymorphism does not contribute to susceptibility to bladder cancer.
Assuntos
Substituição de Aminoácidos/genética , DNA Glicosilases/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único/genética , Neoplasias da Bexiga Urinária/genética , Humanos , Viés de Publicação , Fatores de RiscoRESUMO
The bonding of single diferrocene [Fc(CH(2))(14)Fc, Fc = ferrocenyl] molecules on a metal surface can be enhanced by partial decomposition of Fc groups induced by the tunneling current in scanning tunneling microscopy. Although the isolated intact molecule is mobile on the terrace of Cu(110) at 78 K, the modified molecule is immobilized on the terrace. Calculations based on density functional theory indicate that the hollow site of the Cu(110) surface is the energetically favorable adsorption site for both ferrocene and the Fe-cyclopentadienyl complex, but the latter one possesses a much higher binding energy with the substrate.
RESUMO
We report a generally applicable method to pattern organic molecules on mesoscopic scales. In our method, organic molecular beam deposition was conducted on substrate surfaces prepatterned with materials to which the organic molecules have larger binding energies in comparison to the substrate. Fully uniform nucleation control at these predefined locations can be achieved by an appropriate selection of the growth parameters including temperature and deposition rate. The physical mechanisms involved are studied by Monte Carlo simulations and stand in good agreement with the experimental findings.
RESUMO
We report a physical mechanism responsible for initiating a vacuum breakdown process of a single carbon nanotube (CNT) during field emission. A quasidynamic method has been developed to simulate the breakdown process and calculate the critical field, critical emission current density and critical temperature beyond which thermal runaway occurs before the CNT temperature reaches its melting point. This model is in good agreement with experiments carried out with a single CNT on a silicon microtip.