Showing papers by "Pierre-and-Marie-Curie University published in 1973"
TL;DR: Measurements of the lead isotopic composition and the uranium, thorium, and lead concentrations in meteorites were made in order to obtain more precise radiometric ages of these members of the solar system.
Abstract: Measurements of the lead isotopic composition and the uranium, thorium, and lead concentrations in meteorites were made in order to obtain more precise radiometric ages of these members of the solar system. The newly determined value of the lead isotopic composition of Canyon Diablo troilite is as follows: (206)Pb/(204)Pb = 9.307, (207)Pb/(2O4)Pb = 10.294, and (208)Pb/(204)Pb = 29.476. The leads of Angra dos Reis, Sioux County, and Nuevo Laredo achondrites are very radiogenic, the (206)Pb/(204)Pb values are about 200, and the uranium-thorium-lead systems are nearly concordant. The ages of the meteorites as calculated from a single-stage (207)Pb/(206)Pb isochron based on the newly determined primordial lead value and the newly reported (235)U and (838)U decay constants, are 4.528 x 10(9) years for Sioux County and Nuevo Laredo and 4.555 x 10(9) years for Angra dos Reis. When calculated with the uranium decay constants used by Patterson, these ages are 4.593 x 10(9) years and 4.620 x 10(9) years, respectively, and are therefore 40 to 70 x 10(6) years older than the 4.55 x 10(9) years age Patterson reported. The age difference of 27 x 10(6) years between Angra dos Reis and the other two meteorites is compatible with the difference between the initial (87)Sr/(86)Sr ratio of Angra dos Reis and that of seven basaltic achondrites observed by Papanastassiou and Wasserburg. The time difference is also comparable to that determined by (129)1-(129)Xe chronology. The ages of ordinary chondrites (H5 and L6) range from 4.52 to 4.57 x 10(9) years, and, here too, time differences in the formation of the parent bodies or later metamorphic events are indicated. Carbonaceous chondrites(C2 and C3) appear to contain younger lead components.
502 citations
TL;DR: The evidence of the freemartins suggests that presumptive ovaries, if submitted to an appropriate influence, probably the two kinds of fetal testicular hormones, still may develop testicle-like structures in the place of ovarian follicles.
Abstract: Publisher Summary This chapter presents studies on sex differentiation in mammals. It also discusses some of the problems involved in sex differentiation, especially those concerning the differentiation of the gonads. In both gonads—testes and ovaries—the germ cells are stored in contact with a single type of cell in structures that are isolated from the other tissues or from the blood by a more or less complex basement membrane or wall. Each gonad develops as a tiny swelling of the inner aspect of the mesonephros, usually near a glomerulus or at least near mesonephric tubules. At the surface of this swelling, the cells are arranged more or less regularly in a so-called epithelium although many of these cells are not very different or distinct from those lying beneath, which are often referred to as “mesenchymal cells.” Some cells produce connective fibrils at early stages and can be considered cells of the connective tissue. Among these somatic cells, the usually larger primordial germ cells can be distinguished. The chapter also discusses abnormal developmental processes as in freemartins in cattle, which serve as a classical example of abnormal sex differentiation in mammals. Freemartins are genetic female cattle that develop in parabiosis with at least one male twin. In multiple pregnancies in cattle, the chorions and their blood vessels usually fuse; this permits exchange of blood. The evidence of the freemartins suggests that presumptive ovaries, if submitted to an appropriate influence, probably the two kinds of fetal testicular hormones, still may develop testicle-like structures in the place of ovarian follicles.
487 citations
TL;DR: Reduced alkylated baboon milk lysozyme was subjected to digestion with trypsin and purified by a combination of Dowex 1 (X2) and chromatography and electrophoresis on paper, establishing alignment of the tryptic peptides into a single chain containing 130 amino acids.
33 citations
TL;DR: The casein rniccile in its natural etivironment 111 and in-the clotting phenomenon induced by t&action of rennin (EC 3.4.3); it’ is also the only casein fraction hi cOIlti3iM sugars 12, 31, TO the hCtCXOgC&ty of K-cascin from pooled milk are contributing the genetic variants, but also the non-identical composiPion
30 citations
TL;DR: The preparation by a mild extraction technique of a hydrosoluble adjuvant-active substance (Poly-PA) from the delipidated cells of the human mycobacterial strain Peurois which did no more elicit the arthritis inducing effect was described.
25 citations
TL;DR: Chemical characterization of the neurohypophysial hormones from twelve non-mammalian tetrapods has shown that these species have the same active peptides, mesotocin and arginine vasotoc in contrast to mammals for which oxytocin and lysine vasopressin have been found in the eight species investigated.
Abstract: CHEMICAL characterization of the neurohypophysial hormones from twelve non-mammalian tetrapods, namely, two lungfishes1, three amphibians2–4, four reptiles5–7 and three birds8, has shown that these species have the same active peptides, mesotocin ([Ile8]-oxytocin) and arginine vasotocin ([Arg8]-oxytocin). This is in contrast to mammals for which oxytocin and arginine or lysine vasopressin ([Phe3-Arg8/Lys8]-oxytocin) have been found in the eight species investigated9.
21 citations
TL;DR: Soluble HL-A antigens can be extracted with high yields from whole human platelets or platelet membrane preparations by the non-ionic detergent NP-40, and the two specificities studied could be separated by electrofocusing.
20 citations
TL;DR: If similarities between both enzymes could be established, it was nevertheless possible to differentiate them clearly by their affinity constants for M. luteus cells, by the inhibitory power of N-acetylglucosamine and by their action on chitopentaose, chitotetraose and colloidal chitin.
Abstract: The enzymatic properties ofNephthys hombergii lysozyme were compared with those of hen egg-white lysozyme. The observed results allowed to conclude that if similarities between both enzymes could be established (variation of the initial velocity of lysis as a function of the ionic strength, influence of urea and histamine), it was nevertheless possible to differentiate them clearly by their affinity constants forM. luteus cells, by the inhibitory power of N-acetylglucosamine and by their action on chitopentaose, chitotetraose and colloidal chitin.
10 citations
TL;DR: A comparison of some optical properties of duck II and duck III lysozymes suggests the same disposition of the disulfide bonds in both enzymes.
5 citations
01 Jan 1973
TL;DR: In this paper, photoluminescence processes in Bi3+ centers were investigated in various host materials such as rare earth oxides, vanadates or gallates and in alkaline earth antimonates.
Abstract: Photoluminescence processes in Bi3+ centers are investigated in various host materials such as rare earth oxides, vanadates or gallates and in alkaline earth antimonates, using excitation and fluorescence spectra, thermoluminescence, phosphorescence decay and lifetime measurements, between 4 K and 400 K.
4 citations
07 May 1973
TL;DR: This paper defines the pairing of two stochastic processes; the Ito stoChastic integral is a particular kind of pairing.
Abstract: This paper studies stochastic distributed parameter systems with stochastic inputs. It defines the pairing of two stochastic processes; the Ito stochastic integral is a particular kind of pairing.