川の中の昆虫たち

There is provided a novel derivative of 2-acetoxybenzoic acid, i.e., 1-O-(2\u27-acetoxy)benzoyl-α-D-2-deoxyglucopyranose, which is suitable for the attainment of high 2-acetoxybenzoic acid blood levels without irritation of the gastrointestinal lining

Excess-noise-enhanced parametric down conversion

We calculate the influence of excess noise on parametric down conversion in an unstable optical parametric oscillator (OPO), using a quantum quasimode description. We find a strongly enhanced pair photon generation rate below threshold as compared to a conventional stable cavity setup of comparable gain and loss. In addition, the oscillation threshold is lowered due to the influence of the excess noise and the squeezing properties of the emitted light are significantly changed. In general, the maximal quantum-noise suppression in one quadrature component is reduced, which poses strong limitations for the practical usefulness of a geometrically unstable OPO source. The analytical results from our quasimode description are in good agreement with numerical simulations using a positive-P representation of the field in mode space and in position space

The determination of pentobarbital and other barbiturates in blood plasma by gas—liquid chromatography with on-column and pre-column butylation

Two g.l.c. methods for the determination of pentobarbital and other barbiturates are reported. In the first method the plasma samples are extracted with toluene; the toluene layer is back-extracted with a small volume of a tetrabutylammonium hydroxide solution of which an aliquot is injected into the gas Chromatograph. This method is simple and rapid, and sensitive enough for monitoring pentobarbital plasma concentrations in the therapeutic range. A number of barbiturates are not well extracted from toluene by tetrabutylammonium hydroxide because of ion-pair partitioning. The extraction efficiency of barbiturates from toluene is much improved by back-extraction of the toluene layer with a tetramethylammonium hydroxide solution; clean chromatograms are obtained from blank plasma when the toluene layer is back-extracted, instead of evaporated, prior to derivative formation. This modification is introduced in the second method; an aliquot of the tetramethylammonium hydroxide layer is subjected to a pre-column butylation procedure which converts the barbiturates completely without any decomposition in the injection port; the sensitivity is at least as good as that of the on-column technique