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We used remote sensing imagery to characterize the hydrological dynamics of 8404 temporary freshwater wetlands (playas) in Texas (Landsat 5 TM WRS-2 P30/R36) from 2008 to 2011, comparing known wet and dry periods, and related these to land use within 100 m. Hydroperiods were highly variable, and peak water availability occurred in different seasons in(More)
(nominal inner diameter: 0.6 mm) needles into rotating 40 wt.-% PEI (branched; average molecular weight, M w ~ 25 000; water-free; Aldrich) solutions in methanol. The SWNT/PEI composite fibers were characterized by SEM (LEO 1590 VP microscope) and micro-Raman spectroscopy (Jobin± Yvon Horiba high-resolution LabRam micro-Raman spectrometer; helium±neon(More)
A microneedle array has been fabricated and applied to the measurement of transdermal skin potentials in human subjects. Potential changes were recorded in the vicinity of superficial wounds, confirming the generation of a lateral electric field in human skin. The measured electric field decays with distance from the wound edge, and is directed towards the(More)
Stochastic molecular sensors based on resistive pulse nanopore modalities are envisioned as facile DNA sequencers. However, recent advances in nanotechnology fabrication have highlighted promising alternative detection mechanisms with higher sensitivity and potential single-base resolution. In this paper we present the novel self-aligned fabrication of a(More)
The fabrication of nanopores in thin silicon nitride and aluminum oxide membranes by water vapor assisted, low-energy (0.2-20 kV) electron beam machining using a scanning electron microscope (SEM) is described. Using this technique, pores with diameters ranging in size from < 5 to 20 nm are easily formed. The nanopores are characterized by SEM, transmission(More)
A DNA sequencing device which integrates transverse conducting electrodes for the measurement of electrode currents during DNA translocation through a nanopore has been nanofabricated and characterized. A focused electron beam (FEB) milling technique, capable of creating features on the order of 1 nm in diameter, was used to create the nanopore. The device(More)
Transverse and axial trapping forces are calculated in the ray optics regime for a multiple-beam fiber-optic light-force trap for dielectric microspheres located both on and off axis relative to the beam axis. Trap efficiencies are evaluated as functions of the effective index of refraction of the microspheres, normalized sphere radius, and normalized beam(More)
Rapid and specific on-site detection of disease-causing or toxin-producing organisms is essential to public health and safety. Many molecular recognition methods target ribosomal RNA sequences due to their specificity and abundance in the cell. In this work RNA targets were identified and quantified using a colorimetric bioassay. Peptide nucleic acid (PNA)(More)
A new microfabrication technology for the design and realization of 1 x n and n x n fiber-optic switches, x, xy, and xyz translational stages, optical scanners, fiber-fiber couplers, and fiber-planar-waveguide couplers is presented. This technology is based on bulk anisotropic etching and offers significant improvements over present micro-optical and(More)