X‐RAY DIFFRACTION OF BIOLOGICAL AND SYNTHETIC APATITES
X‐RAY DIFFRACTION OF BIOLOGICAL AND SYNTHETIC APATITES
复制标题
生物和合成磷灰石的 X 射线衍射
DOI：
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发表时间：
1955
影响因子：
5.2
通讯作者：
O. Trautz
中科院分区：
文献类型：
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作者：
O. Trautz
在过去的5到10年里，X射线衍射仪设计的改进使我们有机会重新审视我们对钙化组织结构和磷灰石结构的概念。微束技术现在可以在小到30微米的区域内研究组织切片中的晶体种类和晶体取向。进一步缩小面积是可能的，但会带来相当大的不便。当伴随着截面厚度的相应减小时，光束照射的衍射物的量如此之小，以至于曝光时间延长到数百小时。高亮度的微焦点X射线衍射管可将曝光次数减少50倍。新型盖革计数器X射线衍射仪具有较高的反射角测量精度和较高的弱反射探测灵敏度，是研究磷灰石化学成分的重要仪器。在脊椎动物的矿化组织中，即在牙釉质、牙本质、牙骨质和骨中发现的唯一晶体物种是磷灰石。尽管极力寻找最精细的细节，但在衍射图上没有发现任何反射，表明存在另一种结晶化合物。当然，在X射线衍射研究中，牙釉质是主要使用的，因为它的磷灰石比骨的磷灰石结晶得更好。在人的门牙釉质中，通常可以观察到两个纤维结构相交，角度可达60‘。在鲨鱼的牙釉质中，它们相交成直角？牙釉质的物理性能受这种取向的影响。指导取向的因素必须在有机基质中找到。牙本质、牙骨质和骨的衍射图通常不会显示这样的取向，因为基质中的单个蛋白质纤维是在许多方向上定向的。然而，如果选择组织学方法显示蛋白质纤维平行取向的特殊小区域，那么X射线检查也将揭示磷灰石的优先取向。在某些特殊品种的牙骨质和骨中，观察到了高度平行取向的磷灰石微晶。根据衍射线的展宽估计了微晶的尺寸。因此，在人类门牙釉质和骨骼中，人们发现平均大小分别为600和200A，3，或870和290A？不同研究人员得出的结果不同，主要是由于组织中的微晶取向不同，形成“纤维”结构，
The improvement during the last 5 to 10 years in the design of X-ray diffraction equipment gives us an opportunity to re-examine our concepts of the structure of calcified tissues and the structure of the apatites. The microbeam techniques now permit the study of the crystal species and crystal orientation in tissue sections on areas as small as 30 microns.‘ Further reduction of the area is possible, but entails considerable inconveniences. When accompanied by a corresponding reduction in the thickness of the section, then the amount of diffracting matter which is irradiated by the beam is so small that the exposure times are prolonged to several hundred hours. The microfocus X-ray diffraction tubes of high brilliance can reduce the exposure times by a factor of 50. The new Geiger counter X-ray diffractometer, with its higher precision in the measurement of the reflection angles and the higher sensitivity in the detection of weak reflections, is essential in the study of the chemical composition of the apatites. The only crystal species found in the mineralized tissues of vertebrates, i.e., in enamel, dentin, cementum, and bone, is an apatite. In spit.e of pressing the search to the finest details, no reflection has been found on the diffractograms indicating the presence of another crystalline compound. Naturally, for the X-ray diffraction studies, dental enamel has been chiefly used, since its apatite is much better crystallized than the apatite of bone. In human incisor enamel, usually two fiber structures are observed intersecting at angles up to 60’. In shark’s enamel they intersect a t right angles? The physical properties of the enamels are conditioned by this orientation. The factors directing the orientation must be found in the organic matrix. The diffractograms of dentin, cementum, and bone usually do not reveal such an orientation, as the individual protein fibers of the matrix are oriented in many directions. However, if special small areas are selected in which histological methods have shown a parallel orientation of the protein fibers, then X-ray examination will also reveal the preferred orientation of the apatite. In certain special varieties of cementum and bone, a high degree of parallel orientation of the apatite crystallites has been observed. The size of the crystallites is estimated from broadening of the diffraction lines. Thus, in human incisor enamel and in bone, one finds an average size of 600 and 200 A.,3 respectively, or of 870 and 290 A? The difference in the results obtained by the various investigators is chiefly due to differences in the The crystallites in the tissues are oriented, forming “fiber” structures,