326 lieber eine Steinersche eombinatorische Aufgabe, welche im 45 sten Bande dieses Journals, Seite 181, gestellt worden ist. (Von Herrn Reifs in Frankfurt a. M.) 1. Welche Zahl N von Elementen hat die Eigenschaft, dafs sich die Elemente so zu dreien ordnen lassen, dafs je zwei in einer , aber nur in einer Verbindung vorkommen? Die Antwort auf diese Frage ist folgende: Damit die (mittelbare) Darstellung aller möglichen Zweier durch Dreier, wie man die fragliche Operation nennen kann, möglich sei, ist es nothwendig und ausreichend, dafs die Zahl N die Form 6w-fl oder 6tt-f-3 habe.Dafs N ungerade sein müsse, erhellt daraus, dafs jedes Element mit jedem der JV-l anderen und zwar immer mit zweien auf einmal verbunden sein, dafs also N -l gerade sein müsse. Dafs ferner N von einer der beiden Formen 6fi-fl oder 6n~j~ 3 sein müsse, ist eben so leicht einzusehen; denn die Anzahl aller vorkommenden Dreier mufs dem dritten Theile aller möglichen Zweier gleich sein, da jeder Dreier implicite drei Zweier darstellt. Bezeichnet man daher jene Anzahl durch A (N) und N selbst durch 2^-f l, so hat man A (N) = A(2r-\-l) = |r(2v+l); also mufs entweder v oder 2^-j~l durch 3 theilbar sein. Im ersten Falle hat man im zweiten N = 6i*-{-3.
No abstract
The uptake of 131I by the thyroid of the rat has been investigated under various conditions of stress.The acute change always consists in a considerable reduction of the rate of uptake of 131I irrespective of the nature of the stress. This acute inhibition in the uptake of 131I is independent of the anterior pituitary lobe, since it occurs in the normal and hypophysectomized animal alike. It is also independent of the presence of the adrenals. The inhibition of the uptake of 131I by the thyroids occurs in vivo only; their ability to take up 131I in vitro is not impaired.All the acute changes seen under stress conditions can be readily reproduced by treatment with adrenaline, which shows the same inhibitory effect on normal and hypophysectomized animals, the action being equally transitory.It is suggested that the acute changes in thyroid function seen under stress conditions are entirely independent of the anterior pituitary and are caused by increased release of vasoconstrictor substances.An increased uptake rate of 131I by the thyroid was seen 24 hr after the acute stress. This was thought to be caused by a compensatory increase in the secretion of thyrotrophic hormone by the anterior pituitary.It has been reported previously [Haigh, Reiss & Reiss, 1954] that the rate of uptake of 131I by the human thyroid during the first hour after intravenous injection of this tracer may be considerably decreased in conditions of severe mental tension. This state was shown to be only transitory, since the thyroids of the investigated subjects showed a normal or even increased 24-hr uptake rate if their function was not other¬ wise disturbed. It was suggested that this initial inhibition of 131I uptake might be due to an increased concentration of vasoconstrictor substances in the blood. Supporting evidence was provided by preliminary experiments carried out on rabbits under Nembutal anaesthesia in which the uptake slope was completely flattened after intravenous infusion or injection of adrenaline.The investigations described in this paper were undertaken with the object of analysing the reaction of the thyroid to different stress conditions. A further purpose was to clarify and differentiate between the roles played by the pituitary, the adrenal and vasoconstrictor substances in the response of the thyroid to stress. METHODSThe rats used in this study were of the Wistar (Portón) strain. They were fed on Parkes' diet no. 41, and kept in a thermo-regulated room at 70 + 5°F. Hypophys¬ ectomy was performed by the paratracheal route and adrenalectomy by the dorsal route. 2i J. Endoc.
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