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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Inorganic chemistry 15 (1976), S. 1810-1814 
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Inorganic chemistry 19 (1980), S. 2551-2556 
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 52 (1980), S. 375-377 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 52 (1980), S. 384-384 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 50 (1992), S. 144-148 
    ISSN: 1432-0827
    Keywords: Enamel ; Fluoride ; Hydroxyapatite ; Magnesium ; Octacalcium phosphate ; 32Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Considerable evidence suggests that an acidic calcium phosphate, such as octacalcium phosphate (OCP) or brushite, is involved as a precursor in enamel and other hard tissue formation. Additionally, there is in vitro evidence suggesting that fluoride accelerates and magnesium inhibits the hydrolysis of OCP to hydroxyapatite (OHAp). As the amount of OCP or brushite in enamel cannot be measured directly in the presence of an excess of hydroxyapatite, a procedure was developed that allows for their indirect in vivo quantification as pyrophosphate. This permits study of the effects of fluoride and magnesium ions on enamel mineral synthesis. Rat incisor calcium phosphate was labeled by intraperitoneal injection of NaH2 32PO4. The rats were then subjected to various fluoride and magnesium treatments with subcutaneous implanted osmotic pumps. They were then killed at predetermined intervals; the nascent sections of the incisors were collected, cleaned, and pyrolyzed at 500°C for 48 hours to convert acidic calcium phosphates to calcium pyrophosphate; the pyrophosphate was separated from orthophosphate by anion-exchange chromatography; and the resulting fractions were counted by liquid scintillation spectrometry. The activities of the pyro- and orthophosphate fractions were used to calculate the amount of acidic calcium phosphate present in the nascent mineral. The results demonstrated that the percentage of radioactive pyrophosphate in nascent incisors decreased with time, with increasing serum F- concentration, and with decreasing serum magnesium content. The technique described here should prove to be a powerful new tool for studying the effects of various agents on biological mineral formation.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 35 (1983), S. 783-790 
    ISSN: 1432-0827
    Keywords: Amorphous calcium phosphate ; Apatite ; Calcification ; Hydrolysis ; Octacalcium phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The hydrolysis of previously prepared amorphous calcium phosphate (ACP) was studied in a solution “saturated” with ACP; this eliminated the initial consumption of acid due to ACP dissolution. The procedure established that conversion of a high-concentration ACP slurry to an apatite involves two processes: the first process consumes acid and indicates the formation of a more acidic calcium phosphate intermediary with the solubility of octacalcium phosphate (OCP); the second process consumes base and indicates the conversion of the intermediary to apatite and, possibly, direct conversion of ACP to apatite. The thermodynamic analysis of the solution composition data suggests that ACP converts into a nonstoichiometric apatite when the OCP-like intermediary is formed, and a stoichiometric apatite is formed when no OCP-like intermediary is involved.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 32 (1980), S. 55-62 
    ISSN: 1432-0827
    Keywords: Apatite ; Carbonate apatite ; Hydrolysis ; Impurities ; Octacalcium phosphate ; Sodium ; Tooth enamel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Octacalcium phosphate (Ca8H2(PO4)6·5H2O) is considered to be a precursor in the formation of apatite in bones and teeth; a crucial step for incorporation of impurities appears to occur during its hydrolysis. The present study examines the role that octacalcium phosphate plays in the process of incorporation of carbonate into apatite. Chemical, X-ray diffraction, and infrared techniques were used. When octacalcium phosphate is hydrolyzed in the presence of sodium and carbonate ions in aqueous media, approximately one sodium and one carbonate ion seem to substitute for a calcium and phosphate ion, respectively, in forming apatite, and thea axis is shortened. The infrared spectrum of the product indicates that the carbonate is in the type B site, which is presumed to be a phosphate site. This mechanism is of particular importance since the presence of carbonate in human enamel appears to be related to caries susceptibility. A structural mechanism for the incorporation of impurities during hydrolysis of octacalcium phosphate is presented.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 30 (1965), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Duck eggs were the most susceptible to bacterial spoilage, and turkey eggs were at least as resistant as chicken eggs and in some experiments appeared significantly more resistant. Under storage for 6 weeks at room temperature, however, the ability to resist bacteria was essentially unchanged in duck eggs and very markedly lowered in chicken eggs. Similarly, duck eggs lost very little quality (Haugh units) upon prolonged storage, and chicken eggs lost interior quality much faster. Bacterial penetration studies of chicken and duck exterior structures with model systems demonstrated that the outer shell membrane was the least resistant, followed by the shell and then the inner shell membrane. No consistent or significant differences in bacterial penetration were found between chicken and duck eggs, although the inner shell membrane of the former was thicker than that of the latter. Egg albumen was implicated as a major barrier to bacterial egg spoilage; conalbumin was an important inhibitor in egg white.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 111 (1923), S. 881-882 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR WILLIAM BAYLISS has pointed out, in NATURE for May 19, p. 666, that he is unable to find any account of experiments on the dissociation curve of hæmoglobin at gas pressures considerably greater than that at which the hæmoglobin is presumed to be saturated. He seems to imply that there is no ...
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Materials Research 6 (1976), S. 213-236 
    ISSN: 0084-6600
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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