University of Texas at Austin

About: University of Texas at Austin is a education organization based out in Austin, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 94352 authors who have published 206297 publications receiving 9070052 citations. The organization is also known as: UT-Austin & UT Austin.

Quantitative optical spectroscopy for tissue diagnosis

Abstract: The interaction of light within tissue has been used to recognize disease since the mid-1800s. The recent developments of small light sources, detectors, and fiber optic probes provide opportunities to quantitatively measure these interactions, which yield information for diagnosis at the biochemical, structural, or (patho)physiological level within intact tissues. However, because of the strong scattering properties of tissues, the reemitted optical signal is often influenced by changes in biochemistry (as detected by these spectroscopic approaches) and by physiological and pathophysiological changes in tissue scattering. One challenge of biomedical optics is to uncouple the signals influenced by biochemistry, which themselves provide specificity for identifying diseased states, from those influenced by tissue scattering, which are typically unspecific to a pathology. In this review, we describe optical interactions pursued for biomedical applications (fluorescence, fluorescence lifetime, phosphorescence, and Raman from cells, cultures, and tissues) and then provide a descriptive framework for light interaction based upon tissue absorption and scattering properties. Finally, we review important endogenous and exogenous biological chromophores and describe current work to employ these signals for detection and diagnosis of disease.

The trouble of thinking: Activation and application of stereotypic beliefs.

Abstract: Two studies investigated the effects of cognitive busyness on the activation and application of stereotypes. In Experiment 1, not-busy subjects who were exposed to an Asian target showed evidence of stereotype activation, but busy subjects (who rehearsed an 8-digit number during their exposure) did not. In Experiment 2, cognitive busyness once again inhibited the activation of stereotypes about Asians. However, when stereotype activation was allowed to occur, busy subjects (who performed a visual search task during their exposure) were more likely to apply these activated stereotypes than were not-busy subjects. Together, these findings suggest that cognitive busyness may decrease the likelihood that a particular stereotype will be activated but increase the likelihood that an activated stereotype will be applied.

Generation of Squeezed States by Parametric Down Conversion

Abstract: Squeezed states of the electromagnetic field are generated by degenerate parametric down conversion in an optical cavity Noise reductions greater than 50% relative to the vacuum noise level are observed in a balanced homodyne detector A quantitative comparison with theory suggests that the observed squeezing results from a field that in the absence of linear attenuation would be squeezed by greater then tenfold

Nanopores and Apparent Permeability of Gas Flow in Mudrocks (Shales and Siltstone)

Abstract: Gas-producing mudrock systems are playing an important role in the volatile energy industry in North America and will soon play an equally important role in Europe. Mudrocks are composed of very fine grained particles, and their pores are very small, at the scale of nanometers. Gas production from these strata is much greater than what is anticipated given their very low Darcy permeability. In this paper, images of nanopores obtained by Atomic Force Microscopy (AFM) are presented for the first time. Gas flow in nanopores cannot be described simply by the Darcy equation. Processes such as Knudsen diffusion and slip flow at the solid matrix separate gas flow behaviour from Darcy-type flow. We present a formulation for gas flow in the nanopores of mudrocks based on Knudsen diffusion and slip flow. By comparing this new gas flow formulation and Darcy flow for compressible gas, we introduce an apparent permeability term that includes the complexity of flow in nanopores, and it takes the form of the Darcy equation so that it can easily be implemented in reservoir simulators. Results show that the ratio of apparent permeability to Darcy permeability increases sharply as pore sizes reduce to smaller than 100 nm. Also, Knudsen diffusion's contributions to flow increase as pores become smaller. Unlike Darcy permeability, which is a characteristic of the rock only, permeation of gas in nanopores of mudrocks depends on rock, gas type and operating conditions.