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The relative enthalpy of YBa2Cu3O7-d has been measured between the temperatures 273 and 700 K. From these data, we find that the electronic contribution to the specific heat is linear in temperature with a Sommerfeld constant of 25±3 mJ/mole. K2. We analyze the data to show that the normal state of YBa2Cu3O7-d is described by two conduction bands and strong electron-phonon coupling. The electron-phonon coupling is, in fact, sufficient to account for the highTc in YBa2Cu3O7-d.

Pseudomonas aeruginosaCSU, a nongenetically engineered bacterial strain previously shown to bind dissolved hexavalent uranium (as UO22+and/or its cationic hydroxy complexes), shows promise as the basis of an immobilized‐cell process for removal of dissolved uranium from contaminated wastewaters. A number of polymeric materials, including calcium alginate, polyacrylamide, polysulfone, and polyurethane, were evaluated as possible immobilization matrices for lyophilized biomass of P. aeruginosaCSU. Polyurethane‐based materials such as hydrogel were identified as superior candidates for biomass immobilization. A novel polyurethane gel‐bead fabrication technique was developed and successfully demonstrated at pilot‐plant scale for producing mass quantities of spherical, uniform‐size beads. The immobilized bacterial biomass was evaluated via the measurement of sorption isotherms and dynamics within a batch, stirred‐tank reactor; and loading and elution behavior within a continuous, upflow, packed‐bed columnar reactor. Sorption equilibrium and dynamics in a batch stirred tank were modeled with a pore‐diffusion mass transfer model, by which a pore‐diffusion coefficient was determined to be approximately 2.0 × 10−6cm2/s for uranyl ion transport through the polyurethane gel matrix. The biosorbent beads were regenerable with dilute (0.01–0.1 M) sodium carbonate solutions. Preliminary column breakthrough‐elution studies indicated that P. aeruginosaCSU biomass immobilized within polyurethane gel beads was effective for removal of uranium from low‐concentration, acidic wastewaters.

Five unique fluorinated analogs, 8acand 15a,b, of the monoamine oxidaseA inhibitor 3isopropoxyphenoxathiin 10,10dioxide II were prepared viaoxidation of the corresponding phenoxathiins 7and 14. 3Fluoro7isopropoxy 7a, 2fluoro3isopropoxy 7b, and 2,7difluoro3isopropoxyphenoxathiin 7c were prepared by a modification of the Mauthner synthesis which involved cyclization of the corresponding 2hydroxy4isopropoxythiophenols 4with the appropriate 2halonitrobenzenes 5in the presence of potassium tertbutoxide. Preparation of 2,8difluoro3isopropoxyphenoxathiin 14b from 4band 2,4difluoronitrobenzene 5c employing similar methods failed, leading instead to a novel macrocycle 9. Attempts to obtain 2fluoro7isopropoxyphenoxathün 14a and the 2,8difluoro analog 14bviatrifluoroacetic acid deprotection of intermediate thioprotected 2nitrophenyl 2thiophenyl ethers 11aand cfollowed by cyclization of the resulting thiols were also unsuccessful. Deprotection of 11awith trifluoroacetic acid produced only complex product mixtures, while similar deprotection of 11cand treatment of the resulting crude product with potassium tertbutoxide in refluxing dimethylformamide produced the 2,7difluorophenoxathiin analog 7c, a result consistent with a Smiles rearrangement of the intermediate thiol 12prior to ring closure. The phenoxathiins 14were ultimately prepared by a modification of a relatively unexploited phenoxathiin synthesis involving the intramolecular radical substitution at sulfur of 2aminophenyl 2thiophenyl ethers 13containing paramethoxybenzyl and methoxymethylthioprotecting groups.