Friendship, love, and marriage and their relationship to my ceramic art

Call number: LD2668 .R4 ART 1989 C66Master of ArtsAr

Development and Persistence of 'Static' or 'Dead' Zones in Flows

Certain ceramic products are formed through extrusion processes, where a slurry is forced through small openings to form such products as filters. At the top is a large tank. The slurry is forced through the tank into an extrusion chamber, and then out through slots to form the finished product. [The slurry may be thought of as a mixture of clay (or other polymers), water, and other binders. There are many ways to model this mixture, some of which will be discussed in this report. For instance, the slurry can be modeled as a non-Newtonian fluid, a two-phase flow with liquid and solids, or a viscoelastic fluid. One can also model the mixture as an elongated particle suspension in water, where changes in the orientation of the particles could affect the flow.] After the extrusion process is complete, one finds that ‘dead zones’ of dry paste accumulate in two areas. Most prominently, they occur at the lower corners of the tank. They also occur on the floor of the extrusion chamber near the slots, both near and away from the walls. Since we will consider wall effects in the tank, for the extrusion chamber we consider only flow cells sufficiently far away from the walls. Then we may exploit the periodic nature of the device and consider only a single flow cell. The aim of this project is to determine the formation mechanisms of these dead zones, and see how they affect the overall flow

Intensification of North American Megadroughts through Surface and Dust Aerosol Forcing

Tree-ring-based reconstructions of the Palmer drought severity index (PDSI) indicate that, during the Medieval Climate Anomaly (MCA), the central plains of North America experienced recurrent periods of drought spanning decades or longer. These megadroughts had exceptional persistence compared to more recent events, but the causes remain uncertain. The authors conducted a suite of general circulation model experiments to test the impact of sea surface temperature (SST) and land surface forcing on the MCA megadroughts over the central plains. The land surface forcing is represented as a set of dune mobilization boundary conditions, derived from available geomorphological evidence and modeled as increased bare soil area and a dust aerosol source (32deg-44degN, 105deg-95degW). In the experiments, cold tropical Pacific SST forcing suppresses precipitation over the central plains but cannot reproduce the overall drying or persistence seen in the PDSI reconstruction. Droughts in the scenario with dust aerosols, however, are amplified and have significantly longer persistence than in other model experiments, more closely matching the reconstructed PDSI. This additional drying occurs because the dust increases the shortwave planetary albedo, reducing energy inputs to the surface and boundary layer. The energy deficit increases atmospheric stability, inhibiting convection and reducing cloud cover and precipitation over the central plains. Results from this study provide the first model-based evidence that dust aerosol forcing and land surface changes could have contributed to the intensity and persistence of the central plains megadroughts, although uncertainties remain in the formulation of the boundary conditions and the future importance of these feedbacks

Genus Ctenomys (Rodentia, Ctenomyidae) in the eastern lowlands

19 p. : ill., map ; 26 cm.Includes bibliographical references (p. 17-19)."Tuco tucos (genus Ctenomys) of lowland eastern Bolivia are reviewed. Synonymies, references, lists of all known specimens and localities, and new data on morphology and karyology are given for the four species (C. steinbachi, C. minutus, C. conoveri, and C. boliviensis) present. Ctenomys boliviensis displays some morphological variation and considerable karyological variation between localities. Diploid chromosome numbers of Ctenomys in lowland Bolivia range from 10 to 48"--P.[1]

The magic bullet: Creating Indium-111 bombesin targeting vectors for use in diagnostic imaging of prostate and breast cancer [abstract]

Abstract only availableBackground: According to the American Cancer Society, over 68,000 men and women will die from prostate and breast cancer in this year alone. Prostate, breast and other cancers have been shown to express the BB2 receptor. For the past decade the Hoffman laboratory has been synthesizing radiopharmaceutical conjugates based on the Bombesin (BBN) peptide (Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2) that target the BB2 receptor for diagnosis and treatment of cancer. The radioconjugates are composed of a bombesin targeting vector, linking group, chelation moiety and a radioactive metal. One focus of our group is to investigate the efficacy of new Bombesin Targeting Vectors (BTV) which are derivatives of the BBN peptide. In the sixth position of the BTV is a D-phenylalanine amino acid. Our hypothesis is that the D-phenylalanine is responsible for significantly reducing kidney retention. Reduction of kidney retention is crucial for clinical radiotherapeutic applications because the kidney is often the dose limiting organ. In order to understand the structure function relationship of the D-phenylalanine in the BTV targeting vectors, we synthesized and evaluated the BTV peptide with the L-phenylalanine in the sixth position to determine what effect the stereochemistry has upon the in vitro receptor binding and in vivo pharmacokinetic properties of the peptide. Methods: The peptides were synthesized using solid phase peptide synthesis, purified using RP-HPLC, and characterized using electrospray mass spectrometry. Radiolabeling of the peptides was performed using 111InCl3. In vitro cell binding assays and internalization and efflux studies were performed using the PC-3 human cancer cell line. In vivo pharmacokinetic studies were performed using CF-1 mice. Micro-SPECT (single photon emission computed tomography) imaging studies were performed in PC-3 SCID mice. Results: In vivo pharmacokinetic studies at 15 min post-injection gave 39.85 ± 5.07 %ID/g in the BB2 receptor expressing mouse pancreas for the L-Phe-BTV radioconjugate compared to 10.30 ± 0.34 for the D-Phe-BTV. Surprisingly, the kidney clearance for both radioconjugates was statistically identical. Conclusion: Incorporation of the L-Phe instead of the D-Phe into the sixth position of the BTV had no statistically significant effect upon the renal clearance of the radioconjugate. However, the change in stereochemistry from the L to the D-form had significant effects upon the in vivo uptake and retention of the radioconjugate. Further investigations will be conducted to understand the mechanism responsible for the difference in uptake and retention of the two Bombesin radioconjugates

Electrical transport in amorphous semiconducting AlMgB14 films

The electrical transport properties of semiconducting AlMgB14films deposited at room temperature and 573K are reported in this letter. The as-deposited films are amorphous, and they exhibit high n-type electrical conductivity, which is believed to stem from the conduction electrons donated by Al, Mg, and/or Fe impurities in these films. The film deposited at 573K is less conductive than the room-temperature-deposited film. This is attributed to the nature of donor or trap states in the band gap related to the different deposition temperatures