Neutrons in Biology
Neutrons in Biology
复制标题
生物学中的中子
DOI：
--
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Ernest H. Y. Chu
中科院分区：
文献类型：
--
作者：
Ernest H. Y. Chu
我们所熟悉的晶体材料的极端是单晶和随机粉末。在这两个极端之间的是多晶聚集体，不是随机排列的，而是具有某些优选的取向，这就是建筑材料所采取的形式，无论是钢梁还是人或动物的骨骼。优选取向的细节决定了材料承受任何方向应力的能力。在骨的情况下，关键因素是六方羟基磷灰石晶体的矿物质含量的c轴取向，这可以很容易地通过中子衍射来确定。特别地，它可以利用范围从Imm到IOmm的距离在一块骨的体积上测量。主要的实际问题是避免伴随胶原中的氢的强烈非相干散射;这可以通过热处理最好地实现，并且证明这不影响下面的磷灰石。这些骨骼研究为人类和动物的生活和活动提供了重要的解剖学信息，包括人类股骨的生活史、绵羊的运动、赛马腿的骨折和新石器时代部落的生活方式。我们得出结论，该材料被经济地放置在骨中，以承受预期的生活和环境应力。实验结果的0002磷灰石反射的幅度。碰巧对于随机粉末，0002、1121反射（它们是粉末图案中的相邻线）在强度上近似相等。后一种反射具有多重性，几乎不受择优取向的影响，因此0002/1121比值的数值可以相当准确地作为骨样品在任何选定方向上c轴取向程度的定量测量。·通信地址：英国切尔滕纳姆格洛斯GL 54 SUS，桂亭电力公司，温德鲁什路。Neutrons in Biology，Schoenborn and Knott Plenum Press.纽约。1996 17
The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content the crystals of the hexagonal hydroxyapatite and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilising distances ranging from Imm to IOmm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighbouring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone. • Address for correspondence: Windrush Way, Guiting Power, Cheltenham GLOS GL54 SUS, England. Neutrons in Biology, edited by Schoenborn and Knott Plenum Press. New York. 1996 17