Two different multimetal organic compounds were synthesized and used to deposit thin YBa:Cu oxide films on selected metal and ceramic substrates by the dip-coating method. The rheology of the precursors is strongly influenced by the organic ligand, types of solvent, solvent-water molar ratio, and processing method. The precursor compounds were converted to suitable viscosity to achieve uniform film thickness processing on complex geometry. Superconducting transition temperatures T, in the range of 89 to 93 K have been measured, depending on processing parameters used. The critical current density, J , of the solution-coated films had values comparable to those for polycrystalline samples. Y 123 films exhibit c-axis alignment on Ag substrates. A prototype high-Q cavity was coated with Y123 and its performance was evaluated. I. IntroductiovlOI.LOWING thediscoveryofYBa2Cu307 -,' andtherelated

Melt texture processing of YBa 2 Cu 3 O y is limited by the slow cooling rate and the high temperatures required. Changing the rare earth can improve the processing conditions. The melting point of YbBa 2 Cu 3 O y can be reduced below the melting point of silver by adding silver, Yb 2 BaCuO 5 and/or reducing the oxygen partial pressure. The recrystallization rate of NdBa 2 Cu 3 O y + 0.2Nd 4 Ba 2 Cu 2 O 10 is shown to be extremely rapid. For low values of x , solid solutions of (Yb 1−x Nd x )Ba 2 Cu 3 O y may be able to be melt processed rapidly below the melting point of silver.

The phorbol ester TPA (phorbol 12-myristate 13-acetate) substitutes for CO2 as an agonist for transforming Trypanosoma cruzi epimastigotes to the metacyclic trypomastigote stage in a starvation medium consisting of phosphate buffered saline + 10 mM proline, 10 mM sodium acetate and 0.035% NaHCO3. Since TPA is thought to stimulate protein kinase C by mimicking the activity of the secondary messenger diacylglycerol, the above result suggested that T. cruzi metacyclogenesis could be activated by a Ca(2+)-dependent protein kinase C signal induction pathway. Accordingly, cytosolic calcium flux ([Ca2+]i) in epimastigotes, activated with 5% CO2 or TPA (10(-7) M), was measured with the Ca2+ molecular probe, fluo-3AM. In addition, [Ca2+]i was measured in cells incubated with putative metacyclogenic agonists (e.g. proline, glutamate, bioamines, ionophores and catecholamines). None of the compounds studies, except for EGTA, affected cytosolic Ca2+ levels. Control assays with 11 microM thapsigargin, which mobilizes noncytoplasmic Ca2+ stores by inhibiting endoplasmic reticulum Ca(2+)-ATPase, validated our fluorometric assay procedure. Although thapsigargin significantly increases cytoplasmic Ca2+ fluorescence, it has no effect on transformation. The protein kinase C inhibitors staurosporine, H-7 and HA 1004 were tested for their effect on T. cruzi metacyclogenesis. Low concentrations of staurosporine and HA 1004 significantly elevated Peru strain transformation while H-7 had no effect on Peru strain metacyclogenesis. Inhibitor H-7 did significantly depress CL transformation. The results indicate that induction of T. cruzi metacyclic trypomastigote formation by CO2 and TPA is not accompanied by changes in cytosolic Ca2+ and do not provide supporting evidence for participation of a protein kinase C-mediated phosphoinositide cascade in metacyclogenesis.

No abstract

Solution-Condensed YBa2Cu3O7-x Superconductor Thin Films from Thermosetting Metal-Organic Precursors.-Y-Ba-Cu oxide films are deposited on selected metal and ceramic substrates by the dip-coating method using two solutions of different metal organic precursors, either the metal alkoxides Y(OiPr)3, Ba(OiPr) 2, and Cu(O2C8H15)2 (copper ethyl hexanoate) or the compounds Y(OR)3, Ba(OR)2, and (C5H7O2)2Cu2(µ-OR) with R: -CH2CH2OCH2CH2OEt. Single phase pure YBa2Cu3O7-x thin films with transition temp. of Tc = 89-94 K are obtained after heating at 900-920 • C in air for a short time. The critical current density values Jc of the solution-coated films are comparable to those of polycrystalline samples. On Ag substrates c-axis alignment is observed. -(PAK, S. S.; MONTGOMERY, F. C.; DUGGAN, D. M.; CHEN, K. C.; MAZDIYASNI, K. S.; TSAI, P. K.; PAULIUS, L. M.; MAPLE, M. B.; J.