Steven A. Henck

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We have micromachined a silicon-chip device that transports DNA with a Brownian ratchet that rectifies the Brownian motion of microscopic particles. Transport properties for a DNA 50-mer agree with theoretical predictions, and the DNA diffusion constant agrees with previous experiments. This type of micromachine could provide a generic pump or separation(More)
An interdigitated electrode array (IDEA) device has been designed and used to transport DNA based on a Brownian ratchet mechanism. This migration is produced by the periodic formation of an asymmetric sawtooth electric field in the device. Oligonucleotides of 25, 50, and 100 bases in length were tested using two different array geometries. DNA transport as(More)
In this study an industrial Saccharomyces cerevisiae yeast strain capable of fermenting ethanol from pretreated lignocellulosic material was engineered. Genes encoding cellulases (endoglucanase, exoglucanase and β-glucosidase) were integrated into the chromosomal ribosomal DNA and delta regions of a derivative of the K1-V1116 wine yeast strain. The(More)
Microwave detected, microwave-optical double resonance was used to record the à state electronic spectrum of NH3, NH2D, and NHD2 with both vibrational and rotational resolution. To investigate ND3 with the same resolution as we had with our hydrogen containing isotopomers, a strip-line cell was constructed allowing the simultaneous passage of(More)
Microwave detected, microwave-optical double resonance was used to record the à state electronic spectrum of NH3 , NH2D, and NHD2 with both vibrational and rotational resolution. To investigate ND3 with the same resolution as we had with our hydrogen containing isotopomers, a strip-line cell was constructed allowing the simultaneous passage of(More)
Thresholds have traditionally been represented by a single number; the optimal management of the patient depends on whether his probability of disease is above or below this number. The concept of a threshold as a single number, however, inadequately represents the treatment approach of a group of physicians who do not have all the same threshold or a(More)
With a device that uses microscopic imaging as the signal detection method for online laser light scattering of solutions driven to flow in a capillary tube, we have found that mixing of a solution with water and vice versa induce large numbers of aggregates in the free flow stream. The degrees of aggregation as measured from the total number of aggregates(More)
Using microwave detected, microwave-optical double resonance, we have measured the homogeneous linewidths of individual rovibrational transitions in the à state of NH3, NH2D, NHD2, and ND3. We have used this excited state spectroscopic data to characterize the height of the dissociation barrier and the mechanisms by which the molecule uses its excess(More)
The study of the absorption profile of the uI ‘R 44 and pP SB lines of ammonia at various pressures is reported. The two lines of the observed inversion doublets broaden as the pressure is increased until they overlap. Once the lines have overlapped the spectral profile narrows and then begins to broaden again but at a markedly different rate. This effect(More)
Using microwave detected, microwave-optical double resonance, we have measured the homogeneous linewidths of individual rovibrational transitions in the à state of NH3 , NH2D, NHD2 , and ND3 . We have used this excited state spectroscopic data to characterize the height of the dissociation barrier and the mechanisms by which the molecule uses its excess(More)
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