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1Author    A. Bensaoud, A. Bouhaouss, M. FerhatRequires cookie*
 Title    Ionic Conductivity of Poorly Crystalline Apatite: Effect of Maturation  
 Abstract    This study deals with the effect of maturation on the ionic conduction of poorly crystalline synthetic apatite. The tendency of this materials to crystallise during maturation is accompanied by an improvement of its ionic conductivity cr. At room temperature, a increased by a factor of 300 after 50 days of maturation. The frequency dependence of the ionic conductivity was attenuated gradually during maturation. These results are explained by the short-range organisation of sites with time, and by the fact that the translational movement of the mobile ions becomes less hindered as the material matures. 
  Reference    Z. Naturforsch. 55a, 883—886 (2000); received May 23 2000 
  Published    2000 
  Keywords    Apatite, Maturation, Ionic Conductivity, Crystallinity 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0883.pdf 
 Identifier    ZNA-2000-55a-0883 
 Volume    55 
2Author    H. J. Tochon-Danguy, G. Boivin, M. Geoffroy, C. Walzer, C. A. BaudRequires cookie*
 Title    Physical and Chemical Analyses of the Mineral Substance during the Development o f Two Experimental Cutaneous Calcifications in Rats: Topical Calciphylaxis and Topical Calcergy  
 Abstract    In subcutaneous calcinoses induced in rats by topical calciphylaxis and topical calcergy, the ultrastructural aspects related to the evolution o f calcified deposits were previously described. In the present study by m eans o f X-ray diffraction, infrared spectrometry and electron spin resonance, different biophysical analyses are performed on the mineral substance deposited during developm ent o f calciphylaxis and calcergy. A rapid evolution o f the calcium phosphate deposits into hydroxyapatite was noticed along the first 20 days o f the calcinoses; from then, there is no important m odification even at the later stages, and the characteristics o f the mineral substance are mostly sim ilar to that o f bone tissue. The concentration o f trace elem ents such as M g2+ and F e2+, is found higher in cutaneous calcinoses than in bone tissue. 
  Reference    Z. Naturforsch. 38c, 135 (1983); received July 10 1982 
  Published    1983 
  Keywords    Calcification, Calciphylaxis, Calcergy, Apatite, ESR 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0135.pdf 
 Identifier    ZNC-1983-38c-0135 
 Volume    38 
3Author    E. Klüver, Hk Müller-BuschbaumRequires cookie*
 Title    Uber einen Lanthanoid-Mangan-Apatit: Nd4M n(Si04)30 On a Lanthanoid Manganese Apatite: Nd4M n(S i04)30  
 Abstract    Single crystals of Nd4M n (S i0 4)30 have been prepared by a Bi20 3 flux in closed copper tubes. The colourless crystals show hexagonal symmetry, space group C |h-P 6 3/m, a -9,4986(9), c = 6,944(2) A, Z = 2. Nd4M n (S i0 4)30 crystallizes in the A patite structure and shows Nd3+ and Mn2+ with partly statistical distribution. A s a consequence of this, 0 (2) and 0 (4) are occupying split positions. 
  Reference    (Z. Naturforsch. 50b, 61 [1995]; eingegangen am 25. Juli 1994) 
  Published    1995 
  Keywords    Neodymium, Manganese, Silicon, Apatite, Crystal Structure 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-0061.pdf 
 Identifier    ZNB-1995-50b-0061 
 Volume    50 
4Author    L. G. Petersson, G. Frostell, Sweden, A. LoddingRequires cookie*
 Title    Secondary Ion Microanalysis of Fluorine in Apatites of Biological Interest  
 Abstract    A Cameca IM S 300 ion analyzer has been used to measure fluorine concentrations in tooth material. Samples of human and shark teeth were studied. Negative oxygen primary ions produce secondary mass spectra in which positive as well as negative fluorine ion peaks are well re­ presented. W ith constant measuring conditions, the reproducibility of the F/Ca ion ratios is satis­ factory. Fluorine concentrations in the 10 ppm region are easily recorded. By means of samples previously measured by macroscopic F-determining methods, a calibration can be effected to ob­ tain, from the ion current ratios, at least semiquantitative values of F-concentrations. In a sample of human enamel, the F-concentration was found to vary from about 3000 ppm at the surface to about 100 ppm in the interior. In shark enamel the composition at the surface cor­ responded to nearly saturated fluorapatite, 3.6% F, but the fluorine concentration decreased distinctly at increasing depth. 
  Reference    (Z. Naturforsch. 29c, 417 [1974]; received February 18 1974) 
  Published    1974 
  Keywords    Microanalysis, Fluorine, Teeth, Apatites, Ion Microprobe 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0417.pdf 
 Identifier    ZNC-1974-29c-0417 
 Volume    29