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The paper presents the results of scanning of mechanical properties of coniferous (common pine Pinus sylvestris) and deciduous (small-leaved lime Tiliacordata and common oak Quercus robur) trees wood using nanoindentation on crosscut face. Manifold increase in microhardness H and Young's modulus E has been observed between early and late wood in every annual growth ring. Significant differences in intraring radial dependencies of H and E have been found among studied species. For all studied species the average values of E and H of early wood in each annual ring are found to be independent from ring width, while such dependence for late wood is weak at most. The ring widths measured by nanoindentation coincide with the ones measured by standard optical method within 2–3%. The developed technique and obtained results can be useful (1) to amend the understanding the origins of macromechanical properties of various wood species and their dependence upon microstructural characteristics and growth conditions, (2) to optimize the technologies of growing, reinforcement and subsequent usage of the wood, (3) to develop new independent high resolution methods in dendrochronology. [ABSTRACT FROM AUTHOR]

The relationship between the mechanical properties of anisotropic materials and their thermophysical characteristics was experimentally revealed using the example of Scots pine (Pınus sylvéstris L) wood. By measuring the hardness and principal components of the thermal diffusivity tensor, on three sections (normal to the fibers, tangential, and radial) at different wood moisture content, it has been shown that this relationship can be described by linear functions. This makes it possible to carry out an express assessment of the mechanical properties of anisotropic materials, which normally require labor- and material-intensive destructive tests, by means of contactless nondestructive determination of their thermophysical characteristics using the method of dynamic thermography. [ABSTRACT FROM AUTHOR]

We studied the effects of regular long-term exposure to industrial nanomaterial based on multiwalled carbon nanotubules on the digestive system of mice. Nanomaterial in a concentration of 30 mg/kg was administered with drinking water over 30 days. Tissue specimens from the small intestine and liver were studied by light and electron microscopy. Multiwalled carbon nanotubules caused multiple necrotic foci in the small intestine and mixed parenchymatous degeneration in the liver. These findings suggested that multiwalled carbon nanotubules entering the digestive tract damaged intestinal villi, presumably via mechanical damage to enterocytes. It seems that multiwalled carbon nanotubules could cause degeneration indirectly, by triggering inflammatory reactions and ROS generation. [ABSTRACT FROM AUTHOR]

The recording and the analysis of the radial distributions of H and E can significantly complement the data of traditional methods making dendrochronology more informative and completely objective. A triboindenter TI-950 (Hysitron) was used to determine the nano/microhardness and the Young modulus by means of indenting a trihedral diamond Berkovich indenter with an equivalent tip radius of about 50 nm into end cut wood. In this case, the loading diagram is recorded in the P-h coordinates, where is the instantaneous load applied to the indenter and h is the current depth of its penetration into the material. [Extracted from the article]

To assess the toxicity of carbon nanotubes (CNTs), we modeled the interaction of CNTs with the inorganic component of mammals' bone tissue, calcium hydroxyapatite (HA), Ca(PO)(OH), under the conditions of biomimetic formation of HA/CNT composites containing 0.1, 1, and 5 wt % CNTs. The synthesis products were identified by chemical analysis, X-ray diffraction, thermal analysis, scanning and transmission electron microscopy, and electron diffraction. We assessed the effect of CNTs on the crystallographic and morphological characteristics of nanocrystalline HA, measured the solubility of the HA/CNT composites, and examined their interaction with living organisms (laboratory mice). [ABSTRACT FROM AUTHOR]