A series of uranyl complexes KxUO2Ly(NO3)2, where L is the variable ligand (or ligands), has been prepared; it has been shown that a ligand series may be defined using the antisymmetric stretching frequency of the uranyl entity, and this series exhibits a remarkable parallelism with the spectrochemical series defined by Δ in octahedral complexes of transition metals of the 1st and 2nd series. This parallelism has been rationalized using a mixed ligand field theory in which the uranyl ion is considered subject to bonding with ligands which are arranged hexagonally in a plane equatorial to the O–U–O axis. It is shown that the large changes of ν3 and ν1 are due primarily to electron population of the φu and δu atomic orbitals of uranium. Such population is physically equivalent to the reductions AmO2+ +→AmO2+ and NpO2+ +→NpO2+, which cause a decrease of approximately 100 cm—1 in ν3. It is further shown that Δν̄3 = — electrostatic effect — σ(L→M) — π(L→M) ± π(M→L), where in the last term the plus sign is the more probable, and the results obtained have been rationalized using this equation. Some evidence in favor of linearity of the UO2+ + has also been induced, and a general criterion for distinguishing the difficulty observable ν1 has been reestablished. It has also been shown, although not discussed extensively, that the stability of uranyl complexes should increase, roughly as ν̄3 (or ν̄1) decreases. The discussion of similar effects in vanadyl, titanyl, chromyl, and other oxycations has been deferred to a later time.

The rapid and sensitive detection of Salmonella typhymurium based on the use of a polyclonal antibody immobilized by the Langmuir-Blodgett method on the surface of a quartz crystal acoustic wave device was demonstrated. The binding of bacteria to the surface changed the crystal resonance parameters; these were quantified by the output voltage of the sensor instrumentation. The sensor had a lower detection limit of a few hundred cells/ml, and a response time of B 100 s over the range of 10 2 -10 10 cells/ml. The sensor response was linear between bacterial concentrations of 10 2 -10 7 cells/ml, with a sensitivity of 18 mV/decade. The binding of bacteria was specific with two binding sites needed to bind a single cell. The sensors preserve 75% of their sensitivity over a period of 32 days.

Treatment of a wide variety of lignocellulosic biomass with gaseous ozone results in greatly enhanced susceptibility to cellulase enzyme hydrolysis and to digestion by rumen microorganisms so that it can be used as ruminant animal feed or for the production of glucose via enzymatic hydrolysis. By use of appropriate reaction conditions a useful degree of such pretreatment may be obtained in 1-2 h contact time with an ozone consumption of ca. 4-6% of the dry weight of the biomass.

No abstract

Abstract— The relative reactivity of singlet molecular oxygen, 02(1Δg), α‐,β‐,Γ‐and δ with ‐tocopherol (vitamin E) was investigated using microwave discharge generation as a uniquely clean source of singlet oxygen and using a hydrocarbon solvent to approximate the membrane environment. The relative efficiencies of the tocopherols for O2(1Δg) were found to decrease in the order: D‐α‐tocopherol > D‐β‐tocopheroI > D–Γ‐tocopherol > D‐δ‐tocopherol. The reaction products in all cases were found to be mixtures of quinone and quinone epoxides apparently resulting from decomposition of the primary product, the hydroperoxydienone.