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A new EPR spectrum, arising from defects in diamond created by boron, carbon, and nitrogen ion-implantation, is observed. The spectrum, lattice damage production, and annealing of damage are discussed and are ascribed to amorphous carbon. Ein neues EPR-Spektrum in Diamant wird beobachtet, das von Storstellen herruhrt, die durch Ionenimplantation von Bor, Kohlenstoff und Stickstoff erzeugt wurden. Das Spektrum, die Erzeugung und das Ausheilen der Gitterschaden werden diskutiert und dem amorphen Kohlenstoff zugeschrieben.

Natural type IIa diamonds have been implanted with 70 keV carbon, nitrogen and boron ions. The behaviour of the defects introduced is monitored using electron paramagnetic resonance, absorption, luminescence and Raman scattering measurements. We first describe and discuss the applicability of these techniques. We then present results concerning the introduction rate of the defects and their annealing; these results are briefly discussed.

l -Tryptophan uptake was studied in C6 glial cells and found to be a very rapid and temperature dependent process. Kinetic analysis shows the presence of two saturable transport systems acting at different tryptophan concentrations. Both these high- and low-affinity processes were found in 3T3 fibroblast cultured cells, as well as in synaptosomes and cell suspensions obtained from rat cortex. No Na + requirement could be demonstrated in a wide range of tryptophan concentrations. The data presented here suggest that tryptophan accumulation in glial cells could be dependent on allosteric changes of the carrier, which might be relevant to the understanding of 5-HT synthesis regulation.

The effects of LSD on 5-hydroxytryptamine (5-HT) metabolism were studied in rat hippocampal and striatal slices. One hour after in vivo treatment with the drug (1 mg/kg i.p.) the synthesis of [3H]5-HT from l -[3H]tryptophan ([3]Try) was only decreased in the striatum. This effect was associated with a significant reduction in the accumulation of [3H]Try in tissues, whereas endogenous levels of Try in the striatum and hippocampus were significantly increased by this treatment. Such modifications of 5-HT metabolism could not be reproduced by adding LSD directly into the incubating medium of control slices. The release of [3H]5-HT, synthetized from [3H]Try or taken up by tissues, was very much increased when concentrations of K+ in the incubating medium reached 30 or 50 m M. This effect was counteracted by LSD, the drug being administered previously in vivo or added in vitro. Finally, high concentrations of LSD (0.1 m M) added in vitro induced a reserpine-like effect on newly synthetized as well as exogenous [3H]5-HT: the amine was markedly inactivated in its acidic metabolite.

Les differentes etapes qui gouvernent la production des defauts sont decrites. L'accent est place sur les problemes non encore resolus tels que la determination de l'energie du seuil de deplacement, la mobilite des interstitiels a basse temperature, la nature des defauts dans les zones tres fortement desordonnees. Des mecanismes de type electronique susceptibles d'induire ou d'accelerer la mobilite de defauts de type interstitiel ou lacunaire sont proposes et discutes.

Azathioprine modifies the carcinogenic effect of 7–12 DMBA: if azathioprine is given regularly from the date of carcinogenic stimulus by DMBA or before this stimulus, tumours appear later, are less numerous, and less frequently malignant than in controls given DMBA alone. When azathioprine is only given from the date of appearance of the first tumour, there is a more rapid spread of tumours, but the final number and their malignancy are about the same as if the rats had not been given azathioprine.

Un ensemble de proprietes optiques (indice de refraction, pouvoir rotatoire et sa dispersion, diffusion de la lumiere, spectre d’absorption) de solutions aqueuses de lysozyme a ete determine en faisant varier la concentration en lysozyme et la temperature. On deduit des lois simples des variations observees. Cette simplicite tient a la stabilite des molecules de lysozyme dans les conditions de l’etude.

We have studied the influence of the nature and concentration of donor impurity on the 65°K and 35°K stages in electron irradiated n-type germanium. Because the nature of the impurity does not influence the 65°K stage and because this stage is present alone in lightly doped samples, we confirm that it is associated with the annihilation of a vacancy-interstitial pair. Because the 35°K stage is directly connected to the impurity concentration, and not to the free electron concentration, we conclude that it is associated with the annihilation of a vacancy and interstitial-impurity pair. We have shown that the annihilation of the vacancy-interstitial pair occurs through the interstitial mobility at 65°K, 27°K and 4.5°K depending on its charge state, and that the interstitial-impurity mobility occurs at 35°K. Our model explains easily the radiation annealing, the behavior of irradiated p-type germanium and can be extended to the case of indium antimonide and perhaps of silicon.

An infrared goniometer, shortly described has been used for the determinations of the refractive indices of two interesting acousto-optical materials: lead molybdate (PbMoO 4 ) and paratellurite (TeO 2 ). The given results complete those previously available which concern only the visible range. Coefficients of Sellmeier equations for the whole transparency range of both materials are also given and discussed.

Bourgoin Auguste. Descriptions et diagnoses de Cétonides nouveaux [Col. Scarabaeidae]. In: Bulletin de la Société entomologique de France, volume 31 (6),1926. pp. 69-72.