Topic
Urea
About: Urea is a research topic. Over the lifetime, 21394 publications have been published within this topic receiving 382444 citations. The topic is also known as: carbamide & carbonic acid diamide.
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TL;DR: There is no evidence as yet that tropomyosin forms a part of the myosin molecule, nor has it been possible to separate the adenosine triphosphatase activity.
104 citations
TL;DR: In this article, three water-soluble quaternized cellulose derivatives with degree of substitution values of 0.38, 0.50, and 0.74 were synthesized in NaOH/urea aqueous solutions.
Abstract: Three water-soluble quaternized cellulose derivatives (QCs) with degree of substitution (DS) values of 0.38, 0.50, and 0.74 were synthesized in NaOH/urea aqueous solutions. The flocculation charact...
104 citations
104 citations
TL;DR: The earlier suggestion that active ureogenesis through a functional o-u cycle does exist in some freshwater, air-breathing teleosts is strengthened.
Abstract: The ureogenic potential of five species of freshwater, air-breathing teleosts was studied. The activity of all five enzymes of the ornithine-urea (c-u) cycle could be assayed in four out of the five species. The enzymatic activities were generally high. Physiological levels of ammonia and urea and of enzymes of the o-u cycle have been considered to be associated with the potential for terrestrial life in different species. The species having an efficient o-u cycle had low levels of ammonia and high levels of urea in various tissues. Ammonia was the major excretory product in the aquatic medium in all five air-breathing species. However, the rate of excretion of urea was greater than that of exclusively freshwater teleosts reported earlier. There was apparently no diurnal variation in the rates of excretion of ammonia. The rate of excretion of urea was significantly higher during the night than during the day in only two of the species examined, namely, Heteropneustes fossilis and Anabas testudineus. These observations strengthen our earlier suggestion that active ureogenesis through a functional o-u cycle does exist in some freshwater, air-breathing teleosts.
104 citations
TL;DR: In this paper, N,N′-di(2-ethylhexyl)urea was shown by viscosimetry and FTIR spectroscopy to be associated in heptane at concentrations higher than 10 g l−1.
Abstract: N,N′-Dialkylureas, which form intermolecular hydrogen bonds, are
interesting precursors in the field of supramolecular chemistry.
Particularly, N,N′-di(2-ethylhexyl)urea, which is soluble in
nonpolar solvents, was shown by viscosimetry and FTIR spectroscopy to be associated in heptane at concentrations higher
than 10 g l−1. The interactions involved are strongly reinforced by the cooperative association of two urea groups in the case of bis-ureas
prepared from 2,4-toluene diisocyanate.
104 citations