RESUMO
Regulating the motion of nanoscale objects on a solid surface is vital for a broad range of technologies such as nanotechnology, biotechnology, and mechanotechnology. In spite of impressive advances achieved in the field, there is still a lack of a robust mechanism which can operate under a wide range of situations and in a controllable manner. Here, we report a mechanism capable of controllably driving directed motion of any nanoobjects (e.g., nanoparticles, biomolecules, etc.) in both solid and liquid forms. We show via molecular dynamics simulations that a nanoobject would move preferentially away from the fluctuating region of an underlying substrate, a phenomenon termed fluctuotaxis-for which the driving force originates from the difference in atomic fluctuations of the substrate behind and ahead of the object. In particular, we find that the driving force can depend quadratically on both the amplitude and frequency of the substrate and can thus be tuned flexibly. The proposed driving mechanism provides a robust and controllable way for nanoscale mass delivery and has potential in various applications including nanomotors, molecular machines, etc.
RESUMO
Myeloperoxidase (MPO) is an important metabolizing enzyme involved in oxidative stress responses to some environmental carcinogens including benzene, a chemical associated with bone marrow toxicity and leukemia. A novel multiplex polymerase chain reaction (PCR) technique based on adapter-ligation mediated allele-specific amplification (ALM-ASA) is simple, inexpensive and especially useful for multiplex single nucleotide polymorphisms (SNPs) genotyping. The purpose of this study was to examine the genetic markers associated with acute leukemia from multiple SNPs of MPO found in Chinese Han population. A case-control study was conducted, with 135 patients with adult acute leukemia and 187 cancer-free subjects as a control group. Nine SNPs in promoter and exons were selected that were markers related to gene function and risk of leukemia development. The multiplex PCR technique based on ALM-ASA was used to detect multiple SNP genotypes. The accuracy of ALM-ASA was tested by sequence and PCRrestriction fragment length polymorphism (RFLP) genotyping analysis. No polymorphisms were found at -1468T > C, -1053T > C, 958C > T, 967C > A, 1033 T > C. A marked linkage disequilibrium was found among -1816, -586, and -463 genotypes. Three haplotypes were constructed. SNP and haplotypes analysis showed the frequency of the MPO -463G > A mutant genotypes (G/A+A/A) was significantly less in cancer cases. The results of sequence and PCR-RFLP yielded results similar to ALM-ASA. Data suggest that MPO G-463A mutant genotypes may be associated with a reduced risk of acute leukemia development due to diminished activation of carcinogens. MPO G-463A variant may possess a protective genetic marker against acute leukemia in the Chinese Han population.
