Showing papers by "Aarhus University published in 1969"
TL;DR: (Na + + K + )-ATPase from the outer medulla of rabbit kidney was purified to a specific activity of 881 ± 25 moles Pi/mg protein per hr at 37 C.
143 citations
TL;DR: In this article, the short-lived isotopes of argon, krypton, silver, cadmium, tin, iodine, xenon, platinum, gold, mercury, polonium, radon and francium have been studied by the on-line isotope separator technique.
138 citations
TL;DR: Detailed microscopic studies of the contour length of DNA from a mycoplasma species have shown that the DNA in this organism is organized in a single circular chromosome, 262 microns long, corresponding to a molecular weight of 5.0 × 108 daltons.
Abstract: ELECTRON microscopic studies of the contour length of DNA from a mycoplasma species, Mycoplasma hominis (H 39)1, have shown that the DNA in this organism is organized in a single circular chromosome, 262 microns long, corresponding to a molecular weight of 5.0 × 108 daltons. The genome size of bacterial DNA is only well known for a very few bacteria (genome sizes, 0.8–3.0 × 109 daltons)2, but the genomes in mycoplasmas may well be smaller that those of most or all bacteria. If all or most mycoplasmas were to have this same low chromosomal DNA content, the findings might be taken as a strong indication for their having a common phylogenetic origin as well as justifying the placing of mycoplasmas as a separate class of organisms3.
105 citations
TL;DR: Das olfaktorische Epithel von erwachsenen Katzen wurde nach Perfusionsfixierung with Glutaraldehyd and Nachfixierund mit Osmiumtetroxyd stereomikroskopisch im Totalpraparat and elektronenmikrosKopisch in Schnittserien untersucht.
Abstract: Das olfaktorische Epithel von erwachsenen Katzen wurde nach Perfusionsfixierung mit Glutaraldehyd und Nachfixierung mit Osmiumtetroxyd stereomikroskopisch im Totalpraparat und elektronenmikroskopisch in Schnittserien untersucht. Im Auflichtverfahren zeigt die „Regio respiratoria“ eine blaugrune und die „Regio olfactoria“ eine seidighelle graublaue Interferenzfarbe. Bei starkerer lichtmikroskopischer Vergroserung sind die ausgerichteten Bundel der Sinnesgeiseln zu erkennen. Besondere Aufmerksamkeit wurde dem olfaktorischen Saum gewidmet, der sich in drei Schichten gliedert: 1. In eine Innenzone, die die olfaktorischen Vesikel und die Mikrozotten der Stutzzellen beherbergt. 2. In eine Ausenzone, in der die distalen Segmente der Sinnesgeiseln liegen und 3. in den strukturdichteren Terminalfilm. Die Geiselenden tauchen von unten in den Film ein und tragen dann auf ihrer Membranoberflache entweder Filamenteverdichtungen oder sie sind von einem optisch leeren Hof umgeben. Die distalen Geiselsegmente konnen wahrscheinlich bis 80 μ lang sein, sie enthalten nur zwei mikrotubulare Geiselfibrillen. Das proximale Geiselsegment tragt unmittelbar uber dem Ursprung im olfaktorischen Vesikel eine Ringmanschette. Unterschiedliche Formen der Sinneszellendkolben sprechen dafur, das die Perikarya ihr olfaktorisches Blaschen im Rahmen einer stetigen Mauserung ersetzen konnen. Der vonOkano et al. (1967) als jugendliche Stutzzelle angesehene vierte Zelltyp des Riechepithels ist auch bei der Katze vorhanden. Ein weiterer „funfter Zelltyp“ hat basal im Epithel ein Perikaryon und wie die Sinneszellen einen dunnen peripheren Fortsatz, der mit steifen Mikrozotten in die Innenzone des olfaktorischen Saumes hineinreicht. Es wird diskutiert, wieweit Innenstrukturen des Geiselapparates an den Vorgangen der Aufnahme von Geruchsreizen und der Erregungsbildung beteiligt sein konnen.
105 citations
TL;DR: The particle which contained the (Na + + K + )-activated enzyme system was labeled with 32 P from [32 P]ATP, [ 32 P]ITP and 32 P i and the labeling from these three different sources was influenced by Mg 2+ , Na + , K + , and g-strophanthin.
95 citations
TL;DR: The ultrastructure of human yolk sacs obtained by hysterotomy or hysterectomy from the third to the eleventh week of pregnancy is described with reference to the endoderm, mesenchyme, endodermal tubules and mesothelium.
Abstract: The ultrastructure of human yolk sacs obtained by hysterotomy or hysterectomy from the third to the eleventh week of pregnancy is described with reference to the endoderm, mesenchyme, endodermal tubules and mesothelium. During the fourth to the sixth week of pregnancy the endoderm proliferates to form cords of cells projecting into the mesenchyme. The endodermal cells contain abundant endoplasmic reticulum, glycogen and iron-containing material. Various types of tubules in the endoderm are described. The mesenchymal cells vary in appearance; some are stellate with slender cytoplasmic processes, while others are round. A few show signs of phagocytic capacity. Both the endodermal and the coelomic epithelia possess microvilli and pinocytotic vesicles. A hypothesis relating to the function of the human vitelline endoderm is proposed.
92 citations
TL;DR: Determination of the fractional lithium reabsorption is simple and may be a useful tool for the study o proximal sodium re absorption in intact animals and in patients.
Abstract: About 80 per cent of the filtered lithium is reabsorbed in the tubules; this is the same as the fraction of filtered sodium that is reabsorbed in the proximal tubules. Fractional lithium reabsorption and proximal fractional sodium reabsorption are increased and decreased by the same procedures. Lithium seems to be reabsorbed mainly or exclusively in the proximal tubules. Determination of the fractional lithium reabsorption is simple; it may be a useful tool for the study o proximal sodium reabsorption in intact animals and in patients.
91 citations
TL;DR: Noradrenaline, dopamine and 5-hydroxytryptamine were determined chemically and histochemically in the brains of rats given lithium with the food for three weeks, indicating that prolonged administration of small lithium doses leads to a lowering of the activity in 5- Hydroxytryptamines neurons or an inhibition of the impulse-stimulated release of 5-Hydroxyt Kryptamine at the nerve terminals.
89 citations
TL;DR: In this article, the lifetime of neutral and ionic species of beryllium and boron was measured by using the foil-excitation technique using ion beams from 60 to 400 keV produced with an electromagnetic isotope separator or a heavy-ion accelerator.
Abstract: Lifetimes of excited states in neutral and ionic species of beryllium and boron have been measured by using the foil-excitation technique. Ion beams from 60 to 400 keV produced with an electromagnetic isotope separator or a heavy-ion accelerator were used. The 1600-7000 \AA{} wavelength region was investigated. For low-lying states in Be, the beam-foil excitation mechanism was studied. Mean lives of 11 states in Be I, nine in Be II, and one in Be III have been measured. Three lines belonging to beryllium could not be identified. In the boron case, seven mean lives were determined for excited neutral and ionic states. Transition probabilities and oscillator strengths have been evaluated and compared with theoretical predictions.
79 citations
TL;DR: The results are compatible with an adaptation of the level of (Na+ + K+-ATPase to the sustained increase in reabsorption of sodium following repeated injections of aldosterone to adrenalectomized rats.
76 citations
TL;DR: The activity of rat liver phenylalanine hydroxylase has been measured in systems which, in addition to the components necessary forhydroxylation, contained ascorbic acid and catalase and certain non-reducing inhibitors can also stabilize the enzyme.
Abstract: The activity of rat liver phenylalanine hydroxylase has been measured in systems which, in addition to the components necessary for hydroxylation, contained ascorbic acid and catalase. 6-Methyl-tetrahydropterine or the corresponding 6,7-dimethyl compound was used as tetrahydropterine cofactor. Simple kinetic experiments lead to the determination of rate constants for the following reactions: the aerobic oxidation of the tetrahydropterine cofactor, the reduction of the dihydropterine cofactor by ascorbic acid and other reductants and the conversion of the dihydropterine cofactor from an active to an inactive form. These rate constants are used for the calculation of the actual concentration of tetrahydropterine cofactor in the hydroxylase system and for correction of the measured rates of hydroxylation for the inactivation of the dihydropterine cofactor.
Ascorbic acid, as well as other reductants that may be present, increase the instability of phenylalanine hydroxylase, but this effect is negligible at sufficiently high catalase concentrations. Certain non-reducing inhibitors can also stabilize the enzyme.
The initial rate of reaction at 30° is linear during the first 5 or 6 min. In contrast at temperatures of 25° and below there is a lag period, whose duration may be reduced by preincubation of the enzyme with tetrahydropterine cofactor. A similar preincubation of the enzyme with l-phenylalanine seems to activate the hydroxylase briefly.
TL;DR: Other factors (2,4-dinitrophenol, CN−, epinephrine and ACTH), which could also be shown to reduce the K+ content of the tissue, stimulated 3-O-[14C]methylglucose release with a similar time-lag, and gradually augmented the release in a K+-free medium or in the presence of ouabain.
TL;DR: In this article, the electronic stopping power of heavy ions with 7 ≤ Z, ≤ 54 in low-index directions of thin gold single crystals is measured in the energy range 200 keV ≤ E ≤ 1100 keV.
Abstract: The electronic stopping of heavy ions with 7 ≤ Z, ≤ 54 in low-index directions of thin gold single crystals is measured in the energy range 200 keV ≤ E ≤ 1100 keV. Large oscillations in electronic stopping power are observed for constant ion velocity. The stopping powers of different low-index directions are compared.
TL;DR: In this paper, a 600-keV heavy-ion accelerator equipped with a universal ion source and a magnet capable of separating masses up to uranium was used for beamfoil studies together with a target chamber constructed to fulfill the demands for ion velocities in the energy range of 60-600 keV.
Abstract: A 600-keV heavy-ion accelerator equipped with a universal ion source and a magnet capable of separating masses up to uranium was used for beam-foil studies together with a target chamber constructed to fulfill the demands for ion velocities in the energy range of 60–600 keV. The mean lives for singlets and multiplets of Al i through Al iii in the wavelength range 1700–5000 A are reported. The evaluated mean lives of the 4s2S and 3d2D states in Al i agree within 10% with earlier experimental results obtained by the phase-shift method and the level-crossing technique.
TL;DR: A study of physical behaviour, in particular buoyant density and melting temperature, can yield useful information on base composition in mitochondria of a genetic apparatus, which is at least partially autonomous.
Abstract: THE presence in mitochondria of a genetic apparatus, which is at least partially autonomous, has greatly stimulated interest in the characterization of mitochondrial DNA from various organisms. A study of physical behaviour, in particular buoyant density and melting temperature, can yield useful information on base composition. Related species of mammals, birds, reptiles and plants have mitochondrial DNAs of similar densities1. This is also true for lower organisms—for example, fungi2—although not for the two related flagellates Tetrahymena and Paramecium1. The density of mitochondrial DNA may be higher (birds and plants), similar (mammals and reptiles) or lower (most unicellular organisms) than that of the corresponding nuclear DNA (ref. 1).
TL;DR: The myocardial two-compartment model of the ventricular wall was considered, and a good correlation was found between this model and the results of graphical and computer analyses of time-activity curves obtained by injections of Xe-133 into the left coronary artery.
Abstract: Intra-myocardial injections of Xe-133 into the left ventricular wall revealed time-activity curves which indicate that blood flow in the subepicardial layers is 30 % greater than in the subendocardial layers. A two-compartment model of the ventricular wall was therefore considered, and a good correlation was found between this model and the results of graphical and computer analyses of time-activity curves obtained by injections of Xe-133 into the left coronary artery. The flows of these two compartments and flows after superficial and deep intra-myocardiai injections were not identical. Thus the myocardial two-compartment model must be abandoned. A gradual decrease of flow from the subepicardial to the subendocardial surface is suggested. If this is true then the wash-out curve after intra-coronary injection of Xe-133 is multi-exponential and thereby inaccessible to graphical analysis.
TL;DR: In this article, absolute cross-sections and some target recoil properties have been measured for the production of 43-49 Sc in uranium bombarded with protons of 590 MeV and 18 GeV, using radiochemical and electromagnetic isotope separation techniques.
TL;DR: In this paper, the mean lives of 2p 2 p 0 levels in Li I, Be II and B III belonging to the lithium isoelectronic sequence were measured and the evaluated oscillator strengths were compared with theoretical estimates for the lithium sequence.
TL;DR: In this article, the scattering of argon ions from atoms in the first and second atomic plane of a (100) gold surface is investigated for outgoing directions forming small angles (⩽ 20°) to the surface.
TL;DR: The *-algebra of analytic elements with respect to time translations, which plays a central role in Haag, Hugenholtz and Winnink's formulation of the Kubo-Martin-Schwinger boundary condition, is a quasi-unitary algebra as discussed by the authors.
Abstract: We show that the *-algebra of “analytic elements” with respect to time translations which plays a central role inHaag, Hugenholtz andWinnink's formulation of the Kubo-Martin-Schwinger boundary condition, is a quasi-unitary algebra in the sense ofDixmier. The commutant theorem proved byHaag, Hugenholtz andWinnink is thus reduced toDixmier's commutant theorem for quasi-unitary algebras.
TL;DR: In this paper, experimental evidence on the M1 + E2 transitions following the beta decay of 70 d 175Hf is presented and the absolute transition probabilities and the signs of the mixing parameters, which may be measured in directional correlation experiments, are used to derive the reduced Coriolis matrix element AK and the intrinsic inter-band M1 matrix element G 5 2 7 2.
TL;DR: In this paper, the four diffuse interstellar absorption bands at λ4430, λ4760 and λ4890, and the two diffuse lines at −1.5 and −2.5 are interpreted as belonging to pre-ionization transitions in H− and O−, respectively.
Abstract: The four diffuse interstellar absorption bands at λ4430, λ4760, λ4890, and λ6180 and the two diffuse lines at λ5780 and λ5797 are interpreted as belonging to pre-ionization transitions in H− and O−, respectively. In both cases the identifications are supported by extrapolations of wave numbers of resonance lines along isoelectronic sequences.
TL;DR: In this paper, the authors discuss the slow-down of ions and the directional effects for charged particles, and the reader is referred to the experimental discussion by E. Bogh (this volume, p. 35) and previous publications.
Abstract: At the meeting two subjects were mentioned. The discussion of one subject, ‘Slowing-down of ions’, is reproduced below. The other subject, ‘Directional effects for charged particles’, was treated more summarily and is not included. The reader is referred to, for example, the experimental discussion by E. Bogh (this volume, p. 35), and to previous publications.
TL;DR: A re-investigation of the 175Hf decay scheme by means of Ge(Li) counters, a six-gap magnetic beta-ray spectrometer and coincidence techniques establishes a family of odd-parity levels characterized by the following energies (in keV) and spins and parities: 3536 ( 5 2 − ), 3582 ( tentative, 1 2 − ) and 5149( 3 2 − )).