Doctor of Philosophy

dissertationFamily history has been called the "cornerstone of individualized disease prevention" but it is underutilized in clinical practice. In order to use it more effectively, its role in assessing risk for disease needs to be better quantified and understood. Family history has been identified as an important risk factor for colorectal cancer (CRC) and risk prediction in CRC is potentially worthwhile because of the possibility of preventing the disease through application of individualized screening programs tailored to risk. The overall project objective was to explore how family history can be better utilized to predict who will develop CRC. First, we used the Utah Population Database (UPDB) to define familial risk for CRC in more detail than has previously been reported. Second, we explored whether individuals at increased familial risk for CRC or at increased risk based on other risk factors such as a personal history of CRC or adenomatous polyps, are more compliant with screening and surveillance recommendations using colonoscopy than those who are at normal risk. Third, we measured how well family history can predict who will develop CRC over a period of 20 years, using family history by itself as a risk factor, and also in combination with the risk factor, age. We found that increased numbers of affected first-degree relatives influence risk much more than affected relatives from the second or third degrees. However, when combined with a positive firstdegree family history, a positive second- and third-degree family history can significantly increase risk. Next, we found that colonoscopy rates were higher in those with risk factors, according to risk-specific guidelines, but improvements in compliance are still warranted. Lastly, it was determined that family history by itself is not a strong predictor of exactly who will acquire colorectal cancer within 20 years. However, stratification of risk using absolute risk probabilities may be more helpful in focusing screening on individuals who are more likely to develop the disease. Future work includes using these findings as a basis for a cost/benefit analysis to determine optimal screening recommendations and building tools to better capture and utilize family history data in an electronic health record system

Common Graphics Library (CGL). Volume 1: LEZ user's guide

Users are introduced to and instructed in the use of the Langley Easy (LEZ) routines of the Common Graphics Library (CGL). The LEZ routines form an application independent graphics package which enables the user community to view data quickly and easily, while providing a means of generating scientific charts conforming to the publication and/or viewgraph process. A distinct advantage for using the LEZ routines is that the underlying graphics package may be replaced or modified without requiring the users to change their application programs. The library is written in ANSI FORTRAN 77, and currently uses a CORE-based underlying graphics package, and is therefore machine independent, providing support for centralized and/or distributed computer systems

Tentative Evidence for Relativistic Electrons Generated by the Jet of the Young Sun-like Star DG Tau

Synchrotron emission has recently been detected in the jet of a massive protostar, providing further evidence that certain jet formation characteristics for young stars are similar to those found for highly relativistic jets from AGN. We present data at 325 and 610 MHz taken with the GMRT of the young, low-mass star DG Tau, an analog of the Sun soon after its birth. This is the first investigation of a low-mass YSO at at such low frequencies. We detect emission with a synchrotron spectral index in the proximity of the DG Tau jet and interpret this emission as a prominent bow shock associated with this outflow. This result provides tentative evidence for the acceleration of particles to relativistic energies due to the shock impact of this otherwise very low-power jet against the ambient medium. We calculate the equipartition magnetic field strength (0.11 mG) and particle energy (4x10^40 erg), which are the minimum requirements to account for the synchrotron emission of the DG Tau bow shock. These results suggest the possibility of low energy cosmic rays being generated by young Sun-like stars.Comment: 19 pages, 2 figures, accepted for publication in ApJ Letter

Author Correction: A cell-free platform for the prenylation of natural products and application to cannabinoid production.

In the original version of this Article, the genotype of the M30 mutant presented in Fig. 3b was given incorrectly as Y288V/A232S, and the M31 mutant was given incorrectly as M1/A232S. The correct genotype of the M30 mutant is Y288A/A232S and for M31 it is Y288V/A232S. In addition, to keep consistency in genotype formatting, the genotype of the M27 mutant should be Y288V/G286S. The errors have been corrected in both the PDF and HTML versions of the Article

Adaptive foveated single-pixel imaging with dynamic super-sampling

As an alternative to conventional multi-pixel cameras, single-pixel cameras enable images to be recorded using a single detector that measures the correlations between the scene and a set of patterns. However, to fully sample a scene in this way requires at least the same number of correlation measurements as there are pixels in the reconstructed image. Therefore single-pixel imaging systems typically exhibit low frame-rates. To mitigate this, a range of compressive sensing techniques have been developed which rely on a priori knowledge of the scene to reconstruct images from an under-sampled set of measurements. In this work we take a different approach and adopt a strategy inspired by the foveated vision systems found in the animal kingdom - a framework that exploits the spatio-temporal redundancy present in many dynamic scenes. In our single-pixel imaging system a high-resolution foveal region follows motion within the scene, but unlike a simple zoom, every frame delivers new spatial information from across the entire field-of-view. Using this approach we demonstrate a four-fold reduction in the time taken to record the detail of rapidly evolving features, whilst simultaneously accumulating detail of more slowly evolving regions over several consecutive frames. This tiered super-sampling technique enables the reconstruction of video streams in which both the resolution and the effective exposure-time spatially vary and adapt dynamically in response to the evolution of the scene. The methods described here can complement existing compressive sensing approaches and may be applied to enhance a variety of computational imagers that rely on sequential correlation measurements.Comment: 13 pages, 5 figure

Technical Note: Effect of Epoxy Embedment on Micromechanical Properties of Brown-Rot-Decayed Wood Cell Walls Assessed with Nanoindentation

Mechanical properties of brown-rot-decayed wood cell walls were evaluated using a nanoindentation technique. Epoxy resin is a typical medium for the sample embedding process in nanoindentation. It is assumed that the embedding process does not affect cell wall properties or that any effects are similar for different samples. As part of an investigation of microscale mechanical effects of brown-rot in wood, we applied nanoindentation to cell walls of decayed and nondecayed pine wood samples. For epoxy-embedded samples, there were no differences in modulus and hardness for control and decayed samples. However, for unembedded samples, significant differences were found between control and decayed samples. These results indicate that the epoxy-embedding process may confound micromechanical testing results. We speculate that in this case, epoxy resin penetrated and reinforced the cell wall of decayed samples

Effect of Wood Species on Water Sorption and Durability of Wood-Plastic Composites

Wood-plastic composites (WPCs) were made from isotactic polypropylene and 10 wood species (8 hardwoods and 2 softwoods). Water sorption and durability of the composites were evaluated. WPCs made with eastern redcedar and Osage orange had low moisture sorption characteristics, lower levels of fungal decay, and increased resistance to mold compared with composites made from other species. The color of the composites was initially quite different, reflecting the differences in color of the various wood species, but after outdoor exposure, the samples were similar in appearance. Metals in contact with WPCs corroded during accelerated exposure and the corrosion of galvanized steel was greatest when in contact with WPCs made from southern pine and black walnut. WPCs made from hickory, sweet gum, black cherry, and red oak corroded ordinary steel more than composites containing other species. These results demonstrate that the inherent characteristics of the wood filler can affect the properties of WPCs. The use of durable wood species in WPCs could result in products with improved durability performance