Search results for "Paracrystalline"
showing 3 items of 3 documents
X-ray investigations of the superstructure of collagen
2008
When compared with results from humid fibers, characteristic changes of the SAXS-pattern taken from dried collagen fibers have been observed. The average lateral width of the various reflexions increases with the order of reflexion whereby a fluctuation is superimposed, the type of which cannot easily be related to the reflexion order. Moreover, each of the reflexions is obviously laterally split into three components. An explanation of these characteristics can be given with the aid of a distinct model, assuming that the collagen fibrils have definitely varying diameters along their axis, whereby paracrystalline distortions appear, represented by nematic fluctuations. Additionally, there i…
Ergastoplasmic paracrystalline inclusion bodies in the adipose gonadal envelope and fat body of the glow worm, Lampyris noctiluca (Insecta, Coleopter…
2001
Abstract The gonads of glow worm larvae are enveloped by adipose tissue which represents a specialized fat body. The adipose gonadal envelope, and also to a lesser extent the fat body cells, contain tubular paracrystalline inclusion bodies (PIBs). Cells of other tissues are devoid of such inclusions. The PIBs form in the cisternae of rough ER. In young larvae PIB formation is sparse, but at advanced larval stages PIBs often occur as bundles in stacks of ergastoplasm. Typically, a PIB within a cisterna consists of four to seven parallel tubules. The outer diameter of a tubule is ca 28.8 nm and the width of the tubule lumen ca 12.2 nm. The “wall” of a tubule contains globular protein subunits…
Influence of the arrangement of the crystals and the structure of the noncrystalline regions on the mechanical properties of polyethylene terephthala…
2007
Amorphous samples of polyethylene terephthalate were stretched with different rates and stretching ratios at different temperatures. Afterwards they were crystallized. The arrangement of the crystals and the conformations of the chains in the noncrystalline regions were investigated by means of X-ray wide-angle scattering, X-ray small-angle scattering, birefringence measurements and nuclear magnetic resonance measurements. The influence of the morphological structure on the mechanical strength was determined. The stretching ratio itself generally does not characterize the orientation state. The structure obtained after crystallization depends mainly on the birefringence of the sample after …