Steady State Stress in a Coated Infinite Half-Space Subjected to a Moving Load

This research investigates the use of coatings to mitigate the stress distribution into an infinite half-space. High energy impact phenomenon at velocities exceeding the speed of sound is an important area of interest to the Air Force Research Laboratory. Holloman Air Force Base\u27s High Speed Test Track sustains significant damage due to this phenomenon. In this thesis, the track system and coating are modeled analytically with equations of motion in terms of linear displacements. Coating thickness and material properties of epoxy or polymer laminates are investigated to understand their affect of stress distribution in the rail. An analytic solution is used to verify a finite difference method. It is found that due to limitations in coating thickness of the track system, this property has no significant affect on the stress distribution. However, the shear modulus of the material is found to have a significant affect representing the possible onset of material failure through the consideration of the combined stress field at the coating-rail interface

Preattentive Texture Segmentation and Grouping by the Boundary Contour System

An improved Boundary Contour System (BCS) neural network model of preattentive vision is applied to two images that produce strong "pop-out" of emergent groupings in humans. In humans these images generate groupings collinear with or perpendicular to image contrasts. Analogous groupings occur in computer simulations of the model. Long-range cooperative and short-range competitive processes of the BCS dynamically form the stable groupings of texture regions in response to the images.Air Force Office of Scientific Research (90-0175); Hughes Aircraft Company (SK-902369-SDB

Market Power and Antitrust Issues in the Restructuring of the Electric Industry

Dynegy is one of the country\u27s leading energy merchants - formerly NGC Corporation and Natural Gas Clearinghouse

The Effect of Various Housing Combinations on Voluntary Wheel Activity in Mice

It is widely accepted that mice are active, social animals. Treadmill running, basal cage activity, and voluntary wheel running have all been used in order to study these qualities. Wheel running models have been used as an index of voluntary physical activity and appear to have several correlates in humans. Distances covered and voluntary aspect of many wheel running models allows researchers to study genetic motivators of activity as well as to track responses to training. Often, wheel running models employ a single mouse and wheel per cage, which precludes social interactions and may impact activity levels and other parameters due to anxiety. The mechanisms by which this isolation modifies activity levels are of paramount importance to support accurate translation of results to human application. This study was designed to assess the effects of housing density and wheel availability on activity levels in mice. Six outbred female SENCAR mice (National Cancer Institute, Bethesda, MD) were housed under various conditions by altering the number of animals and exercise wheels per cage. Starting at six weeks of age, mice were given wheel access in one of two cage combinations: one mouse and one wheel (n= 4) or two mice and one wheel (n= 1). Data pertaining to distance and duration ran was recorded daily, with speed being calculated later as the third primary value of interest. Over the study span of 33 weeks the mice were randomly re-assigned to 1 mouse/1 wheel (total 506 days), 2 mice/1 wheel (64 days), and 2 mice/2 wheel (316 days) combinations (1v1, 2v1, and 2v2 respectively). While data was collected for all combinations, 1v1 and 2v2 were maintained for the longest amount of time. Overall, the SENCAR mice would be classified as high-active mice. When standardized per mouse, mice ran significantly less distance per day (p=0.0001) when two mice were housed in the cage regardless of the number of wheels (1v1 = 10.01±4.02, 2v1 = 6.19±3.35, 2v2 = 6.27±3.43 km) as well as less time per day (1v1 = 309.8±109.4, 2v1=186.1±94.5, 2v2=157.4±65.9 mins; p=0.0001). Conversely, speed of activity was significantly faster (p=0.0001) in the 2v2 housing situation (1v1=32.1±5.9, 2v1=33.38±7.0, 2v2=38.4±9.6 m/min). In summary, housing density and wheel availability can alter activity levels in SENCAR mice

Processing of Synthetic Aperture Radar Images by the Boundary Contour System and Feature Contour System

An improved Boundary Contour System (BCS) and Feature Contour System (FCS) neural network model of preattentive vision is applied to two large images containing range data gathered by a synthetic aperture radar (SAR) sensor. The goal of processing is to make structures such as motor vehicles, roads, or buildings more salient and more interpretable to human observers than they are in the original imagery. Early processing by shunting center-surround networks compresses signal dynamic range and performs local contrast enhancement. Subsequent processing by filters sensitive to oriented contrast, including short-range competition and long-range cooperation, segments the image into regions. Finally, a diffusive filling-in operation within the segmented regions produces coherent visible structures. The combination of BCS and FCS helps to locate and enhance structure over regions of many pixels, without the resulting blur characteristic of approaches based on low spatial frequency filtering alone.Air Force Office of Scientific Research (90-0175); Defense Advanced Research Projects Agency (90-0083

Presence or Absence of Skeletal Muscle Dysfunction in Chronic Obstructive Pulmonary Disease is Associated With Distinct Phenotypes

Introduction: Reduced skeletal muscle function and cognitive performance are common extrapulmonary features in Chronic Obstructive Pulmonary Disease (COPD) but their connection remains unclear. Whether presence or absence of skeletal muscle dysfunction in COPD patients is linked to a specific phenotype consisting of reduced cognitive performance, comorbidities and nutritional and metabolic disturbances needs further investigation. Methods: Thirty-seven patients with COPD (grade II–IV) were divided into two phenotypic cohorts based on the presence (COPD dysfunctional, n = 25) or absence (COPD functional, n = 12) of muscle dysfunction. These cohorts were compared to 28 healthy, age matched controls. Muscle strength (dynamometry), cognitive performance (Trail Making Test and STROOP Test), body composition (Dual-energy X-Ray Absorptiometry), habitual physical activity, comorbidities and mood status (questionnaires) were measured. Pulse administration of stable amino acid tracers was performed to measure whole body production rates. Results: Presence of muscle dysfunction in COPD was independent of muscle mass or severity of airflow obstruction but associated with impaired STROOP Test performance (p = 0.04), reduced resting O saturation (p = 0.003) and physical inactivity (p = 0.01), and specific amino acid metabolic disturbances (enhanced leucine (p = 0.02) and arginine (p = 0.06) production). In contrast, COPD patients with normal muscle function presented with anxiety, increased fat mass, plasma glucose concentration, and metabolic syndrome related comorbidities (hypertension and dyslipidemia). Conclusion: COPD patients with muscle dysfunction show characteristics of a cognitive – metabolic impairment phenotype, influenced by the presence of hypoxia, whereas those with normal muscle function present a phenotype of metabolic syndrome and mood disturbances

RESEARCH Open Access

Herbal adaptogens combined with protein fractions from bovine colostrum and hen egg yolk reduce liver TNF-α expression and protein carbonylation in Western diet feeding in rat

Alteration of renal respiratory Complex-III during experimental type-1 diabetes

<p>Abstract</p> <p>Background</p> <p>Diabetes has become the single most common cause for end-stage renal disease in the United States. It has been established that mitochondrial damage occurs during diabetes; however, little is known about what initiates mitochondrial injury and oxidant production during the early stages of diabetes. Inactivation of mitochondrial respiratory complexes or alteration of their critical subunits can lead to generation of mitochondrial oxidants, mitochondrial damage, and organ injury. Thus, one goal of this study was to determine the status of mitochondrial respiratory complexes in the rat kidney during the early stages of diabetes (5-weeks post streptozotocin injection).</p> <p>Methods</p> <p>Mitochondrial complex activity assays, blue native gel electrophoresis (BN-PAGE), Complex III immunoprecipitation, and an ATP assay were performed to examine the effects of diabetes on the status of respiratory complexes and energy levels in renal mitochondria. Creatinine clearance and urine albumin excretion were measured to assess the status of renal function in our model.</p> <p>Results</p> <p>Interestingly, of all four respiratory complexes only cytochrome c reductase (Complex-III) activity was significantly decreased, whereas two Complex III subunits, Core 2 protein and Rieske protein, were up regulated in the diabetic renal mitochondria. The BN-PAGE data suggested that Complex III failed to assemble correctly, which could also explain the compensatory upregulation of specific Complex III subunits. In addition, the renal F₀F₁-ATPase activity and ATP levels were increased during diabetes.</p> <p>Conclusion</p> <p>In summary, these findings show for the first time that early (and selective) inactivation of Complex-III may contribute to the mitochondrial oxidant production which occurs in the early stages of diabetes.</p