Resonant forward-biased guard rings for suppression of substrate noise in mixed-mode CMOS circuits

Previous work at Stanford University has demonstrated that inductance in the substrate connection is the principal problem underlying the coupling of digital switching noise into analog circuits. The low impedance substrate can be treated as a single node over a local area. Switching in the digital circuits produces current transients in the substrate. These transients are subsequently amplified in the analog portions of the overall mixed-mode circuit. Various guard rings and other techniques, including the use of new logic circuit families, have been proposed to suppress this noise. This work demonstrates that by using the capacitance of a forward biased guard ring(s), the substrate noise at a specific frequency(ies) can be reduced by resonating the guard ring capacitance with the substrate lead inductance to provide a very low substrate-to-ground impedance. In this manner, noise at particular frequencies, which are problematic to the analog circuit, can be suppressed. Tuning can be accomplished by varying the current in the forward-biased guard ring diodes

Localisation et dosage du lithium dans les embryons d'amphibiens

info:eu-repo/semantics/publishe

Métabolisme des RNAs pendant l'oogénèse. Effet des histones, de la polylysine et de l'actinomycine sur l'incorporation de l'uridine-3H dans les oocytes isolés et les fragments d'ovaires d'Asterias rubens

Autoradiographic and biochemical experiments using 3H-uridine have been undertaken to check on the regulation of RNA metabolism in oocytes and ovaries of Asterias, by histones and polylysine, and to compare the effects of these substances to those of actinomycin. Heterologous (commercial "arginin-rich" and calf thymus) and homologous histones (extracted from ♂ and ♀ gonads) have been used. The latter were found to be very similar to one another, both in amino acid composition and electrophoretic behaviour. Histones labeled with 14C-lysine and 14C-actinomycin have been used to verify the penetration of these substances into the oocytes. All four agents used have been found to stimulate the uptake of 3H-uridine. Only actinomycin was found to inhibit its incorporation into the total RNA of the oocytes. Autoradiography confirms these results and shows that the synthesis of RNA is inhibited by actinomycin, at first in the nucleolus and then, in the cytoplasm. These results are discussed. © 1968.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

TRANSITION DU STADE PACHYTENE AU STADE DIPLOTENE DE LA MEIOSE CHEZ XENOPUS LAEVIS. ETUDE CYTOCHIMIQUE ET AUTORADIOGRAPHIQUE

The transition from pachytene to diplotene stages is concomitant with the migration of cytoplasmic proteins into the nucleus, into the chromosomes and the nuclear sap. At that time, an important RNA synthesis begins in the germinal vesicle of the young diplotene oocyte and will persist throughout oogenesis. Protease inhibitors (TLCK, TPCK, TAME) prevent the decondensation of pachytene chromosomes, while the previous stages of meiosis continue normally. The use of 3H TAME shows that this molecule enters the germinal cells and their nuclei. Incorporation of 3H uridine into RNA and of L 3H leucine into proteins is also decreased in the presence of the proteolytic enzyme inhibitors. It is logical to think that the unfolding of the lampbrush chromosomes is accompanied by the derepression of numerous sites of RNA synthesis.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Effets de l'actinomycine D et de la puromycine sur le métabolisme de l'oocyte en croissance Étude autoradiographique

Autoradiographic experiments were performed to localize and follow the different types of RNA (s-RNA, r-RNA, m-RNA) synthesized during the maturation of the oocyte. Similar results were obtained on the two different species studied (sea urchin, Xenopus). Incorporation of 3H-cytidine and 3H-uridine is observed in a preferential manner in the nucleolus and is inhibited by actinomycin D but not by puromycin. The latter, on the other hand, inhibits the incorporation of 5-methylcytosine observed in the cytoplasm (s-RNA). After maturation, the oocyte ribosomes are completely inactive. Puromycin inhibits 80% of the incorporation of phenylalanine into the oocyte proteins, while actinomycin has no effect on the synthesis of these proteins during growth. Nevertheless, actinomycin given during oogenesis seems to have an effect on the cleavage of the eggs, at the time of fertilization. These results are discussed and hypothesis proposed, to try and explain the role of this highly active RNA which is seen in the germinal vesicle of the oocytes, and the significance of the inertness of the ribosomes in the mature egg. © 1964.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Incorporation in vitro de glycocolle-I-14C dans les oocytes d'Astéries

An autoradiographic method, based on the observation of individual particles, was used to determine the relative specific radioactivity of RNA and of the proteins in the different parts of the oocytes of Asterias rubens. The nucleolus incorporates glycine in both fractions about 100 times more rapidly than the cytoplasm. © 1953 Birkhäuser Verlag.SCOPUS: ar.jinfo:eu-repo/semantics/publishe