1,853 research outputs found
Bad expression influences time to androgen escape in prostate cancer
<b>OBJECTIVE</b>: To assess the role of selected downstream Bcl-2 family members (Bad, Bax, Bcl-2 and Bcl-xL) in the development of androgen-independent prostate cancer (AIPC), as androgen-deprivation therapy is the treatment of choice in advanced prostate cancer, yet patients generally relapse and progress to an AI state within 18–24 months.
<b>PATIENTS, MATERIALS AND METHODS</b>: The patient cohort was established by retrospectively selecting patients with prostate cancer who had an initial response to androgen-deprivation therapy, but subsequently relapsed with AIPC. In all, 58 patients with prostate cancer were included with matched androgen-dependent (AD) and AI prostate tumours available for immunohistochemical analysis; two independent observers using a weighted-histoscore method scored the staining. Changes in Bad, Bax, Bcl-2 and Bcl-xL expression during transition to AIPC were evaluated and then correlated to known clinical variables.
<b>RESULTS</b>: High Bad expression in AD tumours was associated with an increased time to biochemical relapse (<i>P</i> = 0.007) and a trend towards improved overall survival (<i>P</i> = 0.053). There were also trends towards a decrease in Bad (<i>P</i> = 0.068) and Bax (<i>P</i> = 0.055) expression with progression to AIPC. There were no significant results for Bcl-2 or Bcl-xL.
<b>CONCLUSION</b>: There is evidence to suggest that Bad expression levels at diagnosis influence time to biochemical relapse and overall survival, and that levels of pro-apoptotic proteins Bad and Bax fall during AIPC development. Bad might therefore represent a possible positive prognostic marker and potential therapeutic target for AIPC in the future
Use of a scanning optical profilometer for toolmark characterization
An optical profilometer has been used to obtain 3-dimensional data for use in two research projects concerning toolmark quantification and identification. In the first study quantitative comparisons between toolmarks made using data from the optical system proved superior to similar data obtained using a stylus profilometer. In the second study the ability of the instrument to obtain accurate data from two surfaces intersecting at a high angle (approximately 90 degrees) is demonstrated by obtaining measurements from the tip of a flat screwdriver. The data obtained was used to produce a computer generated virtual tool, which was then employed to create virtual tool marks. How these experiments were conducted and the results obtained will be presented and discussed
Clarity of Microstamped Identifiers as a Function of Primer Hardness and Type of Firearm Action
The transfer of microstamped identifiers to the primers of fired cartridges was examined using a stereomicroscope and scanning electron microscope (SEM). The identifiers were placed on the firing pins of three different 9mm handguns, namely, a Sig Sauer, a Taurus, and a Hi-Point. Ten different brands of ammunition were fired from each handgun, 100 rounds being fired using each brand for a total of 1000 rounds fired per handgun. The quality of the markings was evaluated using a simple observation rubric. These results were compared to Vickers hardness values obtained from the ammunition primers and are discussed in light of the types of actions of firearms used
Effects of Position, Orientation, and Metal Loss on Ground Penetrating Radar Signals from Structural Rebar
Past experimental work on a highway bridge in central Iowa [1] suggested that ground penetrating radar (GPR) signals could possibly be used to differentiate intact rebar from those having substantial metal loss due to corrosion. That study made use of the amplitudes of GPR signals reflected by rebar, as obtained using a commercial instrument operated in pulse/echo mode. Many factors can contribute to the strength of the echo seen from a given rebar, including the rebar’s length, its distance from and tilt angle relative to the antenna, and the location and size of the metal-loss region. In this paper we systematically investigate these geometric effects. We begin with measurements of reflected signals where only an air layer separates the antenna from the rebar. There, using standard ½-inch diameter rebar, the GPR signal is systematically studied as a function of the length of the rebar, the stand-off distance from the antenna, the rebar tilt angle, and the size of the metal-loss region. The metal loss region is conveniently simulated by taking two parallel and abutting rebar lengths and pulling them apart to introduce a small gap between them. After summarizing the measurements in air, we discuss efforts to extend the study to rebar embedded in concrete. One idea being explored is the use of a powdered “phantom” material (having GPR properties similar to concrete) which can be sandwiched between two concrete blocks. The rebar can then be inserted into the powder layer and its position and orientation can be altered at will. We conclude with a discussion of the implications of our studies to the practical detection of corroded rebar in bridge barrier rails
Effects of building orientation on the residential property
Thesis (B.Sc)--University of Hong Kong, 2010.Includes bibliographical references (p. 72-75).published_or_final_versio
Componential coding in the condition monitoring of electrical machines Part 2: application to a conventional machine and a novel machine
This paper (Part 2) presents the practical application of componential coding, the principles of which were described in the accompanying Part 1 paper. Four major issues are addressed, including optimization of the neural network, assessment of the anomaly detection results, development of diagnostic approaches (based on the reconstruction error) and also benchmarking of componential coding with other techniques (including waveform measures, Fourier-based signal reconstruction and principal component analysis). This is achieved by applying componential coding to the data monitored from both a conventional induction motor and from a novel transverse flux motor. The results reveal that machine condition monitoring using componential coding is not only capable of detecting and then diagnosing anomalies but it also outperforms other conventional techniques in that it is able to separate very small and localized anomalies
Ground penetrating radar applied to rebar corrosion inspection
In this paper we investigate the use of ground penetrating radar (GPR) to detect corrosion-induced thinning of rebar in concrete bridge structures. We consider a simple pulse/echo amplitude-based inspection, positing that the backscattered response from a thinned rebar will be smaller than the similar response from a fully-intact rebar. Using a commercial 1600-MHz GPR system we demonstrate that, for laboratory specimens, backscattered amplitude measurements can detect a thinning loss of 50% in rebar diameter over a short length. GPR inspections on a highway bridge then identify several rebar with unexpectedly low amplitudes, possibly signaling thinning. To field a practical amplitude-based system for detecting thinned rebar, one must be able to quantify and assess the many factors that can potentially contribute to GPR signal amplitude variations. These include variability arising from the rebar itself (e.g., thinning) and from other factors (concrete properties, antenna orientation and liftoff, etc.). We report on early efforts to model the GPR instrument and the inspection process so as to assess such variability and to optimize inspections. This includes efforts to map the antenna radiation pattern, to predict how backscattered responses will vary with rebar size and location, and to assess detectability improvements via synthetic aperture focusing techniques (SAFT)
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