Optimized Volumetric Scanning for X-Ray Array Sources (open access)

Optimized Volumetric Scanning for X-Ray Array Sources

Non-destructive evaluation (NDE) is the science and technology of determining non-invasively the internal structure of manufactured parts, objects, and materials. NDE application areas include medicine, industrial manufacturing, military, homeland security, and airport luggage screening. X-ray measurement systems are most widely used because of their ability to image through a wide range of material densities (from human tissue in medical applications to the dense materials of weapon components). Traditional x-ray systems involve a single source and detector system that rotate and/or translate about the object under evaluation. At each angular location, the source projects x-rays through the object. The rays undergo attenuation proportional to the density of the object's constitutive material. The detector records a measure of the attenuation. Mathematical algorithms are used to invert the forward attenuated ray projection process to form images of the object. This is known as computed tomography (CT). In recent years, the single-source x-ray NDE systems have been generalized to arrays of x-ray sources. Array sources permit multiple views of the object with fewer rotations and translations of the source/detector system. The spatially diverse nature of x-ray array sources has the potential of reducing data collection time, reducing imaging artifacts, and increasing the resolution of …
Date: September 29, 2009
Creator: Lehman, S. K.; Foudray, A. M.; Wang, A.; Kallman, J. S. & Martz, H.
System: The UNT Digital Library
The use of microarrays in microbial ecology (open access)

The use of microarrays in microbial ecology

Microarrays have proven to be a useful and high-throughput method to provide targeted DNA sequence information for up to many thousands of specific genetic regions in a single test. A microarray consists of multiple DNA oligonucleotide probes that, under high stringency conditions, hybridize only to specific complementary nucleic acid sequences (targets). A fluorescent signal indicates the presence and, in many cases, the abundance of genetic regions of interest. In this chapter we will look at how microarrays are used in microbial ecology, especially with the recent increase in microbial community DNA sequence data. Of particular interest to microbial ecologists, phylogenetic microarrays are used for the analysis of phylotypes in a community and functional gene arrays are used for the analysis of functional genes, and, by inference, phylotypes in environmental samples. A phylogenetic microarray that has been developed by the Andersen laboratory, the PhyloChip, will be discussed as an example of a microarray that targets the known diversity within the 16S rRNA gene to determine microbial community composition. Using multiple, confirmatory probes to increase the confidence of detection and a mismatch probe for every perfect match probe to minimize the effect of cross-hybridization by non-target regions, the PhyloChip is able to …
Date: September 15, 2009
Creator: Andersen, G. L.; He, Z.; DeSantis, T. Z.; Brodie, E. L. & Zhou, J.
System: The UNT Digital Library
Congressional Record: Proceedings and Debates of the 111th Congress, First Session (open access)

Congressional Record: Proceedings and Debates of the 111th Congress, First Session

The Congressional Record contains the records for sessions of the U.S. Congress including summaries of proceedings, letters, and speeches for the Senate and House of Representatives. There is a red tab sticking out of page E2255, highlight the speech Hon. Alcee L. Hastings gave about Helen Snapp.
Date: September 14, 2009
Creator: United States. Congress.
System: The Portal to Texas History
Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions (open access)

Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions

The design of high performance catalyst achieving near 100% product selectivity at maximum activity is one of the most important goals in the modern catalytic science research. To this end, the preparation of model catalysts whose catalytic performances can be predicted in a systematic and rational manner is of significant importance, which thereby allows understanding of the molecular ingredients affecting the catalytic performances. We have designed novel 3-dimensional (3D) high surface area model catalysts by the integration of colloidal metal nanoparticles and mesoporous silica supports. Monodisperse colloidal metal NPs with controllable size and shape were synthesized using dendrimers, polymers, or surfactants as the surface stabilizers. The size of Pt, and Rh nanoparticles can be varied from sub 1 nm to 15 nm, while the shape of Pt can be controlled to cube, cuboctahedron, and octahedron. The 3D model catalysts were generated by the incorporation of metal nanoparticles into the pores of mesoporous silica supports via two methods: capillary inclusion (CI) and nanoparticle encapsulation (NE). The former method relies on the sonication-induced inclusion of metal nanoparticles into the pores of mesoporous silica, whereas the latter is performed by the encapsulation of metal nanoparticles during the hydrothermal synthesis of mesoporous silica. The …
Date: September 14, 2009
Creator: Somorjai, G.A.
System: The UNT Digital Library
Effortless Healthy Eating. (open access)

Effortless Healthy Eating.

This document is a guide for the Nutrition Education Lesson Code for Effortless Healthy Eating.
Date: September 2009
Creator: Texas. Department of State Health Services.
System: The Portal to Texas History
Our Changing Planet: The U.S. Climate Change Science Program for Fiscal Year 2010 (open access)

Our Changing Planet: The U.S. Climate Change Science Program for Fiscal Year 2010

The report describes the activities and plans of the Climate Change Science Program (CCSP), which incorporates the U.S. Global Change Research Program established under the Global Change Research Act of 1990, and the Climate Change Research Initiative that was established by the President in 2001. CCSP coordinates and integrates scientific research on climate and global change supported by 13 participating departments and agencies of the U.S. Government. The document highlights recent advances and progress supported by CCSP-participating agencies in each of the program's research and observational elements, as called for in the Strategic Plan for the U.S. Climate Change Science Program released in July 2003, and later modified in the 2008 CCSP Revised Research Plan. The document also describes how observational and predictive capabilities are being improved and used to create tools to support decisionmaking at local, regional, and national scales to cope with environmental variability and change.
Date: September 2009
Creator: U.S. Global Change Research Program and Subcommittee on Global Change Research
System: The UNT Digital Library