DNA mutation detection in a polymer microfluidic network using temperature gradient gel electrophoresis

A miniaturized system for DNA mutation analysis, utilizing temperature gradient gel electrophoresis (TGGE) in a polycarbonate (PC) microfluidic device, is reported. TGGE reveals the presence of sequence heterogeneity in a given heteroduplex sample by introducing a thermal denaturing gradient that results in differences between the average electrophoretic mobilities of DNA sequence variants. Bulk heater assemblies are designed and employed to externally generate temperature gradients in spatial and temporal formats along the separation channels. TGGE analyses of model mutant DNA fragments, each containing a single base substitution, are achieved using both single- and 10-channel parallel measurements in a microfluidic platform. Additionally, a comprehensive polymer microfluidic device containing an integrated microheater and sensor array is developed and demonstrated for performing spatial TGGE for DNA mutation analysis. The device consists of two PC modular substrates mechanically bonded together. One substrate is embossed with microchannels, and the other contains a tapered microheater, lithographically patterned along with an array of temperature sensors. Compared with the external heating approaches, the integrated platform provides significant reduction in power requirement and thermal response time while establishing more accurate and highly effective control of the temperature gradient for achieving improved separation resolution.     

Comparison of SeaWiFS measurements of the Moon with the U.S. Geological Survey lunar model

The Sea-Viewing Wide-Field-of-View Sensor (SeaWiFS) has made monthly observations of the Moon since 1997. Using 66 monthly measurements, the SeaWiFS calibration team has developed a correction for the instrument's on-orbit response changes. Concurrently, a lunar irradiance model has been developed by the U.S. Geological Survey (USGS) from extensive Earth-based observations of the Moon. The lunar irradiances measured by SeaWiFS are compared with the USGS model. The comparison shows essentially identical response histories for SeaWiFS, with differences from the model of less than 0.05% per thousand days in the long-term trends. From the SeaWiFS experience we have learned that it is important to view the entire lunar image at a constant phase angle from measurement to measurement and to understand, as best as possible, the size of each lunar image. However, a constant phase angle is not required for using the USGS model. With a long-term satellite lunar data set it is possible to determine instrument changes at a quality level approximating that from the USGS lunar model. However, early in a mission, when the dependence on factors such as phase and libration cannot be adequately determined from satellite measurements alone, the USGS model is critical to an understanding of trends in instruments that use the Moon for calibration. This is the case for SeaWiFS.     

Restricted use of success cues in retrieval during posthypnotic amnesia.

Evaluated memory for successful and unsuccessful responses to hypnotic suggestions in partially amnesic Ss and in those Ss with normal forgetting. Two analyses (278 undergraduates) demonstrated that highly hypnotizable Ss experiencing partial posthypnotic amnesia tended to show no selective recall for their successes or failures during amnesia, whereas the remainder of the Ss showed definite selective recall of hypnotic success posthypnotically. These findings support F. J. Evans and J. F. Kihlstrom's (see record 1974-06307-001) hypothesis that posthypnotic amnesia involves a disruption of memory organization and suggest that the phenomenon may be mediated by a restriction in the use of normally employed retrieval cues. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Treatment of the drinking driver.

Examined the effect on the 2-yr driving record of drinking drivers referred by the courts to 6 programs for individual treatment. 2,723 drivers treated were classified as light or heavy drinkers, and compared with a no-treatment group similarly classified (n?=?2,127). Outcome criteria were (1) alcohol-related violations, (2) total moving violations, (3) alcohol-related accidents, and (4) total number of accidents. For light drinkers, 5 of the 6 countermeasures were significantly successful on at least 2 of the outcome measures, whereas 1 of them produced a significant decrease on all 4 criteria. Heavy drinkers apparently did not respond to treatment or had significantly worse records than those not treated. It is concluded that a variety of programs successfully treat the light drinker, but many existing programs result in worse records for the heavy drinker. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Calibration and evaluation of nitric acid and ammonia permeation tubes by UV optical absorption

An ultraviolet (UV) optical absorption system has been developed for absolute calibrations of nitric acid (HNO3) and ammonia (NH3) permeation tube emission rates. Using this technique, dilute mixtures containing NH3 or HNO3, both of which interact strongly with many surfaces, are accurately measured at levels below a part per million by volume. This compact and portable instrument operates continuously and autonomously to rapidly (<1 h) quantify the emission of trace gases from permeation devices that are commonly used to calibrate air-monitoring instruments. The output from several HNO3 and NH3 permeation tubes, with emission rates that ranged between 13 and 150 ng/min, was examined as a function of temperature, pressure, and carrier gas flow. Absorptions of 0.015% can be detected which allows a precision (3sigma) of +/-1 ng/min for the HNO3 and NH3 permeation tubes studied here. The accuracy of the measurements, which relies on published UV absorption cross sections, is estimated to be +/-10%. Measurements of permeation tube emission rates using ion chromatography analysis are made to further assess measurement accuracy. The output from the HNO3 and NH3 permeation tubes examined here was stable over the study period, which ranged between 3 months and 1 year for each permeation tube.     

Pharmacological analysis of the contractile role of M2 and M3 muscarinic receptors in smooth muscle

Muscarinic receptors expressed on smooth muscle cells are primarily of the M(2) and M(3) subtypes. The M(3) subtype triggers contraction through an interaction with G(q) proteins to stimulate phosphoinositide hydrolysis and mobilize Ca(2+). In contrast, activation of M(2) receptors modulates contraction by preventing relaxation or by potentiating M(3) receptor-mediated contractions, which enhances heterologous desensitization. These effects can be explained by the coupling of M(2) receptors to G(i) proteins that mediate an inhibition of adenylyl cyclase and calcium-activated potassium channels. The pharmacological antagonism of a response mediated through an interaction between M(2) and M(3) receptors has been shown to resemble the profile of the directly acting receptor (M(3)), primarily, and not that of the conditional receptor (M(2)). Evidence for a contractile role of the M(2) receptor has been obtained by inactivating its signaling pathway with pertussis toxin or by measuring contractile effects of muscarinic agonists after M(3) receptors have been covalently inactivated. Under these conditions, M(2) receptors have been shown to mediate an inhibition of the relaxant effects of agents, like isoproterenol, on the contractile effects of nonmuscarinic spasmogens. Muscarinic M(2) and M(3) receptor knockout mice are useful tools for exploring interactions between these receptors in smooth muscle.     

On-line reoptimization of filter designs for multivariate optical elements

An automated method for producing multivariate optical element (MOE) interference filters that are robust to errors in the reactive magnetron sputtering process is described. Reactive magnetron sputtering produces films of excellent thickness and uniformity. However, small changes in the thickness of individual layers can have severe adverse effects on the predictive ability of the MOE. Adaptive reoptimization of the filter design during the deposition process can maintain the predictive ability of the final filter by changing the thickness of the undeposited layers to compensate for the errors in deposition. The merit function used, the standard error of calibration, is fundamentally different from the standard spectrum matching. This new merit function allows large changes in the transmission spectrum of the filter to maintain performance.     

Detection and discrimination of texture modulations defined by orientation,spatial frequency,and contrast

We sought to determine whether the detection and the identification of texture modulations are mediated by a common mechanism. On each trial two textures were presented, one of which contained a modulation in orientation (OM), spatial frequency (FM), or contrast (CM). Observers were required to indicate whether the modulated texture was presented in the first or the second interval as well as the nature of the texture modulation. The results showed that for two of the three pairwise matchings (OM-FM and OM-CM) detection and identification performance were nearly identical, suggesting a common underlying mechanism. However, when FM and CM textures were paired, discrimination thresholds were significantly higher than detection thresholds. In the context of the filter-rectify-filter model of texture perception, our results suggest that the mechanisms underlying detection are labeled with respect to their first-order input; i.e., the identities of these mechanisms are available to higher levels of processing. Several possible explanations for the misidentification of FM and CM at detection threshold are considered.     

Wind Loads for 19th Century Bridges: Design Evolution, Historic Failures, and Modern Preservation

This paper presents an historical survey of the basis for design wind pressure used by 19th and early 20th century engineers. Events significant to the development of current wind design standards for pedestrian bridges are explored. These include 19th century treatments of wind load, a review of bridge disasters that spurred new thinking, and historical developments of today’s standards.     

The use of background and ability profiles to predict college student outcomes.

To determine whether profiles of predictor variables provide incremental prediction of college student outcomes, the authors 1st applied an empirical clustering method to profiles based on the scores of 2,771 entering college students on a battery of biographical data and situational judgment measures, along with SAT and American College Test scores and high school grade point average, which resulted in 5 student groups. Performance of the students in these clusters was meaningfully different on a set of external variables, including college grade point average, self-rated performance, class absenteeism, organizational citizenship behavior, intent to quit their university, and satisfaction with college. The 14 variables in the profile were all significantly correlated with 1 or more of the outcome measures; however, nonlinear prediction of these outcomes on the basis of cluster membership did not add incrementally to a linear-regression-based combination of these 14 variables as predictors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)