Development of a body force description for compressor stability assessment

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2008.Includes bibliographical references (p. 99).This thesis presents a methodology for a body force description of a compressor with particular application to compressor stability calculations. The methodology is based on extracting blade forces from an axisymmetric flow description and reinterpreting the blade force as a body force acting throughout the fluid. A "blade force average," which translates a three dimensional flow into the axisymmetric description used in this methodology, is described. The methodology is demonstrated using flow fields from three dimensional computational fluid dynamics (CFD) to form body force distributions over the range of flow coefficients in which converged solutions can be obtained and using two dimensional CFD to extend the description to lower flows. The connection between specific flow features and the body force is described for a sample compressor, along with the effect of using averages other than the body force average when reducing the three dimensional flow to an axisymmetric description. To assess the body force modeling procedure, flow fields produced by using the body force as input to a compressor flow computation are presented and compared to the flow fields originally used to produce the body forces. While not conclusive, the comparison provides a positive indication that the body force modeling can be useful as part of a stall prediction procedure.by George Kiwada.S.M

Preparation and evaluation of a radiogallium complex-conjugated bisphosphonate as a bone scintigraphy agent

金沢大学医薬保健研究域薬学系Introduction: 68Ga is a radionuclide of great interest as a positron emitter for positron emission tomography (PET). To develop a new bone-imaging agent with radiogallium, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was chosen as a chelating site and Ga-DOTA complex-conjugated bisphosphonate, which has a high affinity for bone, was prepared and evaluated. Although we are interested in developing 68Ga-labeled bone imaging agents for PET, in these initial studies 67Ga was used because of its longer half-life. Methods: DOTA-conjugated bisphosphonate (DOTA-Bn-SCN-HBP) was synthesized by conjugation of 2-(4-isothiocyanatebenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid to 4-amino-1-hydroxybutylidene-1,1-bisphosphonate (alendronate). 67Ga-DOTA-Bn-SCN-HBP was prepared by coordination with 67Ga, and its in vitro and in vivo evaluations were performed. Results: 67Ga-DOTA-Bn-SCN-HBP was prepared with a radiochemical purity of over 95% without purification. 67Ga-DOTA-Bn-SCN-HBP had great affinity for hydroxyapatite in binding assay. In biodistribution experiments, 67Ga-DOTA-Bn-SCN-HBP accumulated in bone rapidly but was hardly observed in tissues other than bone. Pretreatment of an excess amount of alendronate inhibited the bone accumulation of 67Ga-DOTA-Bn-SCN-HBP. Conclusions: 67Ga-DOTA-Bn-SCN-HBP showed ideal biodistribution characteristics as a bone-imaging agent. These findings should provide useful information on the drug design of bone imaging agents for PET with 68Ga. © 2010 Elsevier Inc. All rights reserved

Development of novel radiogallium-labeled bone imaging agents using oligo-aspartic acid peptides as carriers

金沢大学疾患モデル総合研究センター68Ga (T1/2 = 68 min, a generator-produced nuclide) has great potential as a radionuclide for clinical positron emission tomography (PET). Because poly-glutamic and poly-aspartic acids have high affinity for hydroxyapatite, to develop new bone targeting 68Ga-labeled bone imaging agents for PET, we used 1,4,7,10-tetraazacyclododecane-1,4,7,10- tetraacetic acid (DOTA) as a chelating site and conjugated aspartic acid peptides of varying lengths. Subsequently, we compared Ga complexes, Ga-DOTA-(Asp)n (n = 2, 5, 8, 11, or 14) with easy-to-handle 67Ga, with the previously described 67Ga-DOTA complex conjugated bisphosphonate, 67Ga-DOTA-Bn-SCN-HBP. After synthesizing DOTA-(Asp)n by a Fmoc-based solid-phase method, complexes were formed with 67Ga, resulting in 67Ga-DOTA-(Asp)n with a radiochemical purity of over 95% after HPLC purification. In hydroxyapatite binding assays, the binding rate of 67Ga-DOTA-(Asp)n increased with the increase in the length of the conjugated aspartate peptide. Moreover, in biodistribution experiments, 67Ga-DOTA-(Asp) 8, 67Ga-DOTA-(Asp)11, and 67Ga-DOTA- (Asp)14 showed high accumulation in bone (10.5±1.5, 15.1±2.6, and 12.8±1.7% ID/g, respectively) but were barely observed in other tissues at 60 min after injection. Although bone accumulation of 67Ga-DOTA-(Asp)n was lower than that of 67Ga-DOTA-Bn-SCN-HBP, blood clearance of 67Ga-DOTA-(Asp)n was more rapid. Accordingly, the bone/blood ratios of 67Ga-DOTA-(Asp) 11 and 67Ga-DOTA-(Asp)14 were comparable with those of 67Ga-DOTA-Bn-SCN-HBP. In conclusion, these data provide useful insights into the drug design of 68Ga-PET tracers for the diagnosis of bone disorders, such as bone metastases. © 2013 Ogawa et al.CC-BY 4.

N+3 Aircraft Concept Designs and Trade Studies

Appendices A to F present the theory behind the TASOPT methodology and code. Appendix A describes the bulk of the formulation, while Appendices B to F develop the major sub-models for the engine, fuselage drag, BLI accounting, etc

Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent

金沢大学疾患モデル総合研究センターBackgroundSigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)-p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)-p IV. As a result, (+)-[125I]p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)-p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-iodophenol ((+)-IV-OH).Methods(+)-[125I]IV-OH was prepared by the chloramine T method from the precursor. The partition coefficient of (+)-[125I]IV-OH was measured. Biodistribution experiments were performed by intravenous administration of a mixed solution of (+)-[125I]IV-OH and (+)-[131I]p IV into DU-145 tumor-bearing mice. Blocking studies were performed by intravenous injection of (+)-[125I]IV-OH mixed with an excess amount of ligand into DU-145 tumor-bearing mice.ResultsThe hydrophilicity of (+)-[125I]IV-OH was much higher than that of (+)-[125I]p IV. In biodistribution experiments, (+)-[125I]IV-OH and (+)-[131I]p IV showed high uptake in tumor tissues at 10-min post-injection. Although (+)-[131I]p IV tended to be retained in most tissues, (+)-[125I]IV-OH was cleared from most tissues. In the liver, the radioactivity level of (+)-[125I]IV-OH was significantly lower at all time points compared to those of (+)-[131I]p IV. In the blocking studies, co-injection of an excess amount of sigma ligands resulted in significant decreases of tumor/blood uptake ratios after injection of (+)-[125I]IV-OH.ConclusionsThe results indicate that radioiodinated (+)-IV-OH holds a potential as a sigma receptor imaging agent