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Texture analysis with microbeam scanning diffraction enables the local mapping of three-dimensional crystallite orientation in heterogeneous natural and synthetic materials. Cortical (compact) bone is an example of a hierarchically structured biocomposite, which is built mainly of cylindrical osteons, having a lamellar texture at the micrometre level. In this work, a combination of microbeam synchrotron X-ray texture analysis with thin sections of osteonal bone is used to measure the three-dimensional distribution of the c-axis orientation of the mineral apatite in bone with positional resolution of 1 µm. The data reduction procedure needed to go from the stereographic projection of X-ray intensity to the determination of the local orientation of mineralized collagen fibrils is described. The procedure can be applied to other mineralized tissues (such as trabecular bone and chitin) with micrometre scale and biologically controlled fibrillar texture. [ABSTRACT FROM AUTHOR]

Hard X-ray beams with beam sizes in the sub-micrometre range are frequently available at third-generation synchrotron radiation sources, enabling new insights into the structure of materials at different levels of hierarchy by applying novel techniques such as scanning microbeam diffraction or scanning small-angle scattering. The high brilliance of the radiation from wiggler and undulator sources allows in situ experiments such as mechanical testing of single fibres to be performed, and even the combination of microbeam scanning with in situ testing is feasible. Three different experiments on single carbon fibres are presented: an in situ tensile test using a 10 µm collimated beam, a scanning experiment applying a 3 µm beam from a tapered glass capillary, and a scanning experiment with simultaneous in situ bending with a 0.1 µm beam provided by a waveguide structure. [ABSTRACT FROM AUTHOR]

Load bearing biological materials such as bone or arthropod cuticle have optimized mechanical properties which are due to their hierarchical structure ranging from the atomic/molecular level up to macroscopic length scales. Structural investigations of such materials require new experimental techniques with position resolution ideally covering several length scales. Beside light and electron microscopy, synchrotron radiation based x-ray imaging techniques offer excellent possibilities in this respect, ranging from full field imaging with absorption or phase contrast to x-ray microbeam scanning techniques. A particularly useful approach for the study of biological tissues is the combination x-ray microbeam scanning with nanostructural information obtained from x-ray scattering [small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS)]. This combination allows constructing quantitative images of nanostructural parameters with micrometer scanning resolution, and hence, covers two length scales at once. The present article reviews recent scanning microbeam SAXS/WAXS work on bone and some other biological tissues with particular emphasis on the imaging capability of the method. The current status of instrumentation and experimental possibilities is also discussed, and a short outlook about actual and desirable future developments in the field is given. [ABSTRACT FROM AUTHOR]

Sorption and capillary condensation of an organic fluid in ordered mesoporous silica were studied by in situ small-angle X-ray diffraction using synchrotron radiation. The sorption isotherm was calculated from the sample transmission data. The diffraction peaks resulting from the periodic hexagonal arrangement of the pores show characteristic changes of intensity, position and width, and a pronounced hysteresis of these parameters in the capillary condensation/evaporation regime was observed. The change of the peak positions with gas pressure is related to pore lattice deformations due to capillary stresses occurring at the gas–liquid phase transition. [ABSTRACT FROM AUTHOR]

Discusses key issues concerning the use of sophisticated synchrotron radiation techniques such as microbeam diffraction in nanobiosciences. Quality of cross-disciplinary discussion between scientists involved in synchrotron radiation microbeam instrumentation and a broad research community interested in the functional properties of hierarchical biological systems; Analysis of pertinent topics and relevant issues; Implications for studies of synchrotron radiation.

Single carbon fibers were directly heated and tensile tested in vacuum in a specially designed in-situ X-ray testing device. We followed the structural evolution by diffraction of synchrotron radiation X-rays and determined the effect of time, temperature and applied stress on the growth of nanocrystallites as well as their orientational change with respect to the fiber axis. As the nanocrystallites are stacks of graphene sheets, this is a direct measurement of the development of multi-layer graphene with temperature. In the same experiment, size and orientation of pores within the material were obtained from simultaneous in-situ small-angle X-ray scattering. It turned out that the final temperature is decisive for structural evolution, significantly more than time or load. The multi-layer graphene network structure in fibers after heat treatment without stress is stable, whereas this is not the case in fibers without heat treatment, no matter if the carbon fibers were produced from polyacrylonitrile or from mesophase pitch precursor. [ABSTRACT FROM AUTHOR]