1,696 research outputs found
Theoretical prediction of airplane stability derivatives at subcritical speeds
The theoretical development and application is described of an analysis for predicting the major static and rotary stability derivatives for a complete airplane. The analysis utilizes potential flow theory to compute the surface flow fields and pressures on any configuration that can be synthesized from arbitrary lifting bodies and nonplanar thick lifting panels. The pressures are integrated to obtain section and total configuration loads and moments due side slip, angle of attack, pitching motion, rolling motion, yawing motion, and control surface deflection. Subcritical compressibility is accounted for by means of the Gothert similarity rule
Oblique Polarized Reflectance Spectroscopy for Depth Sensitive Measurements in the Epithelial Tissue
Optical spectroscopy has shown potential as a tool for precancer detection by discriminating alterations in the optical properties within epithelial tissues. Identifying depth-dependent alterations associated with the progression of epithelial cancerous lesions can be especially challenging in the oral cavity due to the variable thickness of the epithelium and the presence of keratinization. Optical spectroscopy of epithelial tissue with improved depth resolution would greatly assist in the isolation of optical properties associated with cancer progression. Here, we report a fiber optic probe for oblique polarized reflectance spectroscopy (OPRS) that is capable of depth sensitive detection by combining the following three approaches: multiple beveled fibers, oblique collection geometry, and polarization gating. We analyze how probe design parameters are related to improvements in collection efficiency of scattered photons from superficial tissue layers and to increased depth discrimination within epithelium. We have demonstrated that obliquely-oriented collection fibers increase both depth selectivity and collection efficiency of scattering signal. Currently, we evaluate this technology in a clinical trial of patients presenting lesions suspicious for dysplasia or carcinoma in the oral cavity. We use depth sensitive spectroscopic data to develop automated algorithms for analysis of morphological and architectural changes in the context of the multilayer oral epithelial tissue. Our initial results show that OPRS has the potential to improve the detection and monitoring of epithelial precancers in the oral cavity.Biomedical Engineerin
Coronary spiral CT
This dissertation describes the use and clinical potential of ECG gated multislice
spiral computed tomography in patients with coronary artery disease. First the
use of other non invasive cardiac imaging, i.e. the previously mentioned
electron beam CT and magnetic resonance imaging is reviewed (chapter 2.1).
Part 3 contains studies related to the characteristics of multislice spiral CT for
the imaging of the heart and coronary arteries, and the diagnostic potential of
ECG gated spiral CT coronary angiography to detect and visualize obstructive
coronary artery disease in symptomatic patients, using conventional coronary
angiography as the standard of reference. Part 4 is focussed on the feasibility
and characteristics of coronary wall imaging by CT, including the assessment of
non calcified atherosclerotic plaque material. The usefulness of
contrast enhanced multislice spiral CT in symptomatic patients who previously
underwent coronary artery bypass grafting and percutaneous coronary
intervention with stent implantation is discussed in part 5. Finally, the first results with the latest generation 16 slice computed tomography scanners and
patient preparation with ~ receptor blockers are described in part 6, including a
review and future outlook on the continuing development and clinical use of
non invasive coronary angiography with spiral computed tomography
Vanadium (β-(Dimethylamino)ethyl)cyclopentadienyl Complexes with Diphenylacetylene Ligands
Reduction of the V(III) (β-(dimethylamino)ethyl)cyclopentadienyl dichloride complex [η5:η1-C5H4(CH2)2NMe2]VCl2(PMe3) with 1 equiv of Na/Hg yielded the V(II) dimer {[η5:η1-C5H4(CH2)2NMe2]V(µ-Cl)}2 (2). This compound reacted with diphenylacetylene in THF to give the V(II) alkyne adduct [η5:η1-C5H4(CH2)2NMe2]VCl(η2-PhC≡CPh). Further reduction of 2 with Mg in the presence of diphenylacetylene resulted in oxidative coupling of two diphenylacetylene groups to yield the diamagnetic, formally V(V), bent metallacyclopentatriene complex [η5:η1-C5H4(CH2)2NMe2]V(C4Ph4).
Bananas as an Energy Source during Exercise: A Metabolomics Approach
This study compared the acute effect of ingesting bananas (BAN) versus a 6% carbohydrate drink (CHO) on 75-km cycling performance and post-exercise inflammation, oxidative stress, and innate immune function using traditional and metabolomics-based profiling. Trained cyclists (N = 14) completed two 75-km cycling time trials (randomized, crossover) while ingesting BAN or CHO (0.2 g/kg carbohydrate every 15 min). Pre-, post-, and 1-h-post-exercise blood samples were analyzed for glucose, granulocyte (GR) and monocyte (MO) phagocytosis (PHAG) and oxidative burst activity, nine cytokines, F2-isoprostanes, ferric reducing ability of plasma (FRAP), and metabolic profiles using gas chromatography-mass spectrometry. Blood glucose levels and performance did not differ between BAN and CHO (2.41±0.22, 2.36±0.19 h, P = 0.258). F2-isoprostanes, FRAP, IL-10, IL-2, IL-6, IL-8, TNFα, GR-PHAG, and MO-PHAG increased with exercise, with no trial differences except for higher levels during BAN for IL-10, IL-8, and FRAP (interaction effects, P = 0.003, 0.004, and 0.012). Of 103 metabolites detected, 56 had exercise time effects, and only one (dopamine) had a pattern of change that differed between BAN and CHO. Plots from the PLS-DA model visualized a distinct separation in global metabolic scores between time points [R2Y(cum) = 0.869, Q2(cum) = 0.766]. Of the top 15 metabolites, five were related to liver glutathione production, eight to carbohydrate, lipid, and amino acid metabolism, and two were tricarboxylic acid cycle intermediates. BAN and CHO ingestion during 75-km cycling resulted in similar performance, blood glucose, inflammation, oxidative stress, and innate immune levels. Aside from higher dopamine in BAN, shifts in metabolites following BAN and CHO 75-km cycling time trials indicated a similar pattern of heightened production of glutathione and utilization of fuel substrates in several pathways
The Political Participation of First Year Social Work Students: Does Practice Specialization Matter?
This study identifies the types of political participation engaged in by MSW students (n=214). A self-report survey administered to MSW students at a Northeastern university indicates limited political involvement. MSW students participate in political activities not requiring significant time, energy, or resources. Furthermore, on the scale and its two subscales, micro-oriented students had less political participation than macro-oriented students. This study suggests firstyear social work students may lack the tools to engage in the political process effectively. Schools of social work should include political participation education in both micro and macro foundation courses and field placement
Preliminary Results: Complementary C4:C3 Grazing Systems
Native warm-season grasses (NWSG) can produce high quality forage and high rates of gain for beef cattle. However, little data is available on how NWSG affect the productivity of cow-calf operations on a farm scale. Therefore, we implemented an experiment at three sites, Booneville, AR, Linneus, MO and Louisville, TN, with cow-calf pairs (mature cows over ≥ 3 years old, spring calving). We evaluated two forage systems that mix either a drought or drought/flood tolerant native C4 species [big bluestem (BB) blend or eastern gamagrass (EG)] with a cool-season perennial, tall fescue (TF), and compared them to the most frequently used forage system within the Fescue Belt region, one that relies on TF only. The TN study site contains EG, with big bluestem at the MO site, and both big bluestem and EG at the AR site. Cattle (n = 12 pairs per experimental unit) were weighed yearly before initial grazing and again after final removal. Forage samples (n = 15) were collected at the beginning of grazing and once every twenty-eight days during the grazing season, and finally, at the conclusion of grazing. Harvested forages were tested for forage nutritive content (CP, NDF, ADF) using NIRS. Hay produced per forage system was documented by counting bales and weights of subsamples. The AR site was not able to participate in the first year of the study. Overall, there were no statistical differences between treatments in the first grazing season for either cattle or forage measures. However, cattle spent less time on NWSG in 2021 at the TN site to enable renovation of EG to be completed. Also, TF stands had a significant proportion of volunteer warm-season grasses within the pastures. Data from the second year of the study are currently under analysis
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