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Xiong Wen Lou

Publications and source records attributed to Xiong Wen Lou.

6 recordsLinked to original sources
PubMed2006

Spontaneous sharp bending of DNA: role of melting bubbles.

The role of centrally located and distributed base pair mismatches ('melting bubbles') on localized bending and stiffness of short dsDNA fragments is evaluated using time-dependent fluorescence lifetime measurements. Distributed melting bubbles are found to induce larger bending angles and decreased levels of stiffness in DNA than centrally located ones of comparable overall size. Our results indicate that spontaneous local opening-up of the DNA duplex could facilitate sharp bending of short DNA strands even in the absence of DNA binding proteins. We also find that the occurrence of two closely spaced melting bubbles will generally be favored when a large energetic barrier must be overcome in forming the desired bent DNA structure.

Base Pair Mismatch↗
PubMed2006

Comprehensive interpretation of gel electrophoresis data.

From temperature analysis of polyacrylamide gel electrophoresis data for rigid-rod DNA analytes, it is proposed that an entropic force term is responsible for the discrepancy between Ogston-Morris-Rodbard-Chrambach model predictions and experimental results. This entropic force originates from reduction of the orientational freedom of anisotropic analytes in small pores of polyacrylamide gels. Time-dependent fluorescence anisotropy decay measurements confirm that, even in the absence of an external field, orientation of anisotropic analytes is restricted in polyacrylamide gels. A new comprehensive model is proposed that takes this effect into consideration. Predictions based on this model are found to compare favorably with experimental data for linear and three-arm asymmetrically branched rigid-rod DNA analytes covering a broad range of molecular aspect ratios and sizes. A new length scale is also proposed for describing the effect of analyte topology on electrophoretic mobility. This length scale reduces to the analyte radius of gyration in the limiting cases of spherically symmetric and linear rigid-rod species. Based on these results, a general approach is proposed for interpreting gel electrophoresis data of charged analytes possessing simple and complex topologies.

Acrylic Resins↗
PubMed2003

An inorganic route for controlled synthesis of W18O49 nanorods and nanofibers in solution.

In this work, we describe a simple inorganic route for synthesis of monodispersed W(18)O(49) nanorods with dimensional control in the quantum confinement regime. The single-crystalline W(18)O(49) nanorods can be prepared into stable colloidal solutions, or assembled into fibrous and/or paper forms by tuning process parameters. The important role of Na(2)SO(4) salt in the synthesis has been demonstrated. This inorganic route should be feasible for large-scale production of low-dimensional nanostructured W(18)O(49).

Journal Article↗
PubMed2003

Complex alpha-MoO(3) nanostructures with external bonding capacity for self-assembly.

Through manipulating crystal growth directions, we devised a versatile synthetic method to fabricate complex alpha-MoO(3) nanostructures with external bonding capacity for self-organization. Using four-armed forklike alpha-MoO(3) as nanobuilding blocks, we assembled more complex crystal morphologies, such as centrally holed nanorods, tridents, and paintbrushes. With prolonged ultrasonic treatments, pristine forklike alpha-MoO(3) crystals can be turned into less armed nanostructures, giving away the secondary arms (width < 100 nm) at the same time. On the other hand, the resultant alpha-MoO(3) itself can act as a template to produce shaped TiO(2) and other nanocrystals. Square- and horseshoe-shaped nanocrystals of anatase TiO(2) are left undissolved after removing alpha-MoO(3) templates in basic medium.

Journal Article↗