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Showing papers by "University of Iceland published in 1969"


Journal ArticleDOI

109 citations


Journal ArticleDOI
TL;DR: In this article, the isotopic exchange between ice and water is found to take place in temperate glaciers and the exchange causes homogenization of deuterium in snow during summer thaw, together with a general increase in deutetium concentration.

58 citations


Journal ArticleDOI
TL;DR: The effects of extracellularly applied ATP are consistent with the view that they are exerted through changes in membrane permeabilities and that some of these effects are brought about by the adenosine part of the molecule.
Abstract: The effect of external ATP and related compounds on the electrical and mechanical activity of isolated pieces of taenia coli has been studied. ATP, AMP and adenosine caused a decrease in the spontaneous tone, a decrease in the frequency of spike discharge, and hyperpolarization. ATP was up to 100 times as potent an inhibitor of spontaneous activity as AMP or adenosine. GMP, guanosine and inosine had no effect. High K+ contractures were relaxed by the same compounds and adenine, which was the most potent. Here again GMP, guanosine and inosine had no effect. ATP, AMP and adenosine prevented or shortened the initial depolarization produced by acetylcholine and carbachol. Inorganic phosphate was liberated from ATP and AMP applied to the bathing solution. The hydrolysis was not significantly decreased by g-strophanthin. p-Hydroxy-mercuribenzoate caused an initial excitation as well as g-strophanthin but neither inhibited the relaxing effect of ATP. The effects of extracellularly applied ATP are consistent with the view that they are exerted through changes in membrane permeabilities and that some of these effects are brought about by the adenosine part of the molecule.

57 citations


Journal ArticleDOI
TL;DR: In this article, the results of geological, geochemical and isotopic investigations in the Hengill thermal area in Iceland are presented, which may be regarded as typical of the Icelandic high temperature areas.
Abstract: The results of geological, geochemical and isotopic investigations in the Hengill thermal area in Iceland are presented. This area may be regarded as typical of the Icelandic high temperature areas.

51 citations


Journal ArticleDOI
01 Feb 1969-Cancer
TL;DR: Covering membrances as the skin of sausages or wrappings of cellophance and even of cotton fabric form an effective barrier against penetration of polycyclic hydrocarbons, and in particular of 3:4 benzpyrene, without materially destroying the process of soke curing.
Abstract: Home-smoked food processed in Iceland is apt to contain much higher amounts of polycyclic hydrocarbons, including 3:4 benzpyrene, than commercially-smoked food because of heavier and more prolonged smoke exposure. Commercially-smoked meat was found to contain less than 1 μg/kg wet weight 3:4 benzpyrene while a representative sample of home-smoked meat contained 23 μg. Being of higher molecular weight, the polycyclic hydrocarbons have lower power of penetration thaan the phenols so the bulk is found in the superficial layer of the food. Covering membrances as the skin of sausages or wrappings of cellophance and even of cotton fabric, form an effective barrier against penetration of polycyclic hydrocarbons, and in particular of 3:4 benzpyrene, without materially destroying the process of soke curing.

28 citations


Journal ArticleDOI
TL;DR: Six malignant nerve tumours of rats induced by oral N-nitroso-N-methyl-urea were studied electron microscopically and the findings support the opinion that neurinomas arise from Schwannian cells.
Abstract: Es wird uber die Ultrastruktur sechs bosartiger Nerventumoren der Ratte nach oraler Gabe von NMH berichtet. Die Ultrastruktur zeigte trotz einer deutlichen Anaplasie im wesentlichen eine Ubereinstimmung mit der Ultrastruktur menschlicher Neurinome, so das diese experimentellen Tumoren den menschlichen Neurinomen gleichzusetzen sind. Die Befunde erharten die Annahme, das die Neurinome von den Schwannschen Zellen ausgehen. Morphometrische Messungen ergaben bei diesen anaplastischen Tumoren einen hohen Wert fur das Volumen des granularen endoplasmatischen Reticulums, wobei die am starksten verwilderten Tumoren eine deutliche Abnahme des granularen endoplasmatischen Reticulums bei gleichzeitiger Zunahme des Mitochondrienvolumens zeigten.

14 citations