10 research outputs found
Optical Tweezers as a Micromechanical Tool for Studying Defects in 2D Colloidal Crystals
This paper reports on some new results from the analyses of the video
microscopy data obtained in a prior experiment on two-dimensional (2D)
colloidal crystals. It was reported previously that optical tweezers can be
used to create mono- and di-vacancies in a 2D colloidal crystal. Here we report
the results on the creation of a vacancy-interstitial pair, as well as
tri-vacancies. It is found that the vacancy-interstitial pair can be
long-lived, but they do annihilate each other. The behavior of tri-vacancies is
most intriguing, as it fluctuates between a configuration of bound pairs of
dislocations and that of a locally amorphous state. The relevance of this
observation to the issue of the nature of 2D melting is discussed.Comment: 6 pages, 4 figure
The Potential and Challenges of Nanopore Sequencing
A nanopore-based device provides single-molecule detection and analytical capabilities that are achieved by electrophoretically driving molecules in solution through a nano-scale pore. The nanopore provides a highly confined space within which single nucleic acid polymers can be analyzed at high throughput by one of a variety of means, and the perfect processivity that can be enforced
in a narrow pore ensures that the native order of the nucleobases in a polynucleotide is reflected in the sequence of signals that is detected. Kilobase length polymers (single-stranded genomic DNA or RNA) or small molecules (e.g., nucleosides) can be identified and characterized without amplification or labeling, a unique analytical capability that makes inexpensive, rapid DNA sequencing
a possibility. Further research and development to overcome current challenges to nanopore identification of each successive nucleotide in a DNA strand offers the prospect of ‘third generation’ instruments that will sequence a diploid mammalian genome for ~$1,000 in ~24 h.Molecular and Cellular BiologyPhysic