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The application of PIXE and micro-PIXE methods for the description of human aortic wall mineralization including its dynamics is presented. The data was collected both from human autopsy samples and from animal material. The mean concentrations of P, S, Cl, K, Ca, Fe, Cu, Zn, Br, Sr and Pb were determined in tissue samples and in the aortic wall sections. On the basis of PIXE results the following conclusion may be drawn: the concentrations of Ca, Zn, Sr and Pb increase while that of S, Cl and K contents decrease when the mineralization of the vessel wall (determined histochemically) develops. The micro-PIXE method enabled: (1) the determination of the elemental composition of both inorganic and organic materials in the sample, (2) the identification of different Ca—P compounds on the basis of the Ca/P ratio, (3) the investigations of the involvement of other elements in the development of mineralization process (4) the determination of the deposit radii on the basis of Ca concentration and (5) the generalized analysis on the inorganic deposit growth using mathematical description.

Chemical composition of the fluids in the fluid inclusions of quartz from the pegmatite veins of the Yamaguchi W-Cu skarn deposit was measured by a combination of the crush-leach method in deionized water and chemical analysis using PIXE. Chemical composition of the fluids is characterized by a low molar ratio of Na/K and a high Cu concentration. The molar ratio of Cu/(Cu+Fe+Zn) of the fluid inclusions is higher than that of massive sulfide deposits on the seafloor. The molar ratio of Cu/(Cu+Fe+Zn) of the fluid inclusions is similar to the ratios of the vapor-rich fluid inclusions from the quartz-cassiterite veins hosted within the Mole Granite in New South Wales, Australia. The high Cu concentration in fluid inclusions of quartz associated with the pegmatite veins from the Yamaguchi deposit suggests that the fluid emanating from the Miyako granitic melt at the later stage of crystallization had a high Cu content.

Carbonated apatite (CHA) coating on chitosan with gradient distribution was achieved by ions assembly at ambient condition in a short period time. Chitosan hydrogel can directly chelate with calcium via amino groups without inducing carboxyl or hydroxyl group previously. The complexation of chitosan with calcium ions subsequently absorbed phosphate ions via electrostatic interaction. Calcium phosphate (CaP) minerals dispersed in chitosan with the thickness of 0.5 mm is exactly CHA with Ca/P molar ratio of 2.01. The transformation route of CaP salts in chitosan hydrogel started from amorphous calcium phosphate with Ca/P molar ratio of 1.19 after ions assembly, and ended at CHA with help of alkali treatment. The content of calcium and phosphorous element decreased with increasing the depth toward the core according to the energy dispersive spectrometer (EDS) results. The gradient distribution of CHA in chitosan and Vickers hardness of chitosan with CHA coating were similar to the distribution of hydroxyapatite in bone and hardness of weight-bearing bovine bone, respectively.

Microdamage progression in bone is dependent on the ultrastructure of the tissue. Thus, any pathological changes in bone ultrastructure may be reflected in the pattern and capacity of microdamage accumulation. A previous numerical study of microdamage progression in bone using a probabilistic failure analysis approach predicts that the microdamage morphology (either linear microcracks or diffuse damage) is very sensitive to the level of mineralization in bone, which is also implicated in some experimental observations. To examine the prediction, femurs from two strains of mice (C57BL/6J, N = 10 and C3H/HeJ, N = 11) that have distinct mineralization levels were fatigued under four-point bending to create damage in the bone tissues. After testing, the microdamage morphology of the bone samples was examined using bulk-staining technique with basic fuchsin. The results demonstrate that more linear microcracks are observed in femurs of C3H/HeJ (higher mineralization), whereas more diffuse-like damage is found in C57BL/6J femurs (less mineralized). Compared with linear microcracks, the formation of diffuse damage tends to dissipate more energy and help bone to avoid catastrophic failures. Therefore, results from this study may help explain why highly mineralized bone tends to be more brittle. Observations from this study are consistent with the numerical prediction from the previous study, suggesting that mineralization has a significant effect on the microdamage morphology of bone.

A unique hollow microsphere TiO₂/ZnO p–n heterojuction was successfully fabricated via a one-step hydrothermal method for degradation of 2,4-Dinitrophenol. The enhancement of mineralization of 2,4-dinitrophenol (2,4-DNP) via photocatalytic degradation of TiO₂/ZnO p–n heterojuction was investigated. The 2,4-DNP was degraded completely by TiO₂/ZnO, and 78% of the total organic carbon (TOC) was removed which is greatly superior to that on the controlled TiO₂, ZnO with 53%, 45%, respectively. A schematic diagram of photocatalytic oxidation mechanism of 2,4-DNP was also presented by $\cdot$OH radical detection. The oxidation of 2,4-DNP and the intermediate productions was based on the hydroxyl (OH) with a high oxidation potential of 2.8V. Moreover, the excellent stability and reliability of the TiO₂/ZnO composite hollow microsphere photocatalyst demonstrated its promising application for removal of organic pollutant from water.

In order to understand the mechanisms of fracture healing, especially the neovascularization of the callus, we have established a closed femoral fracture model in rats. This chapter describes a microangiography technique that has been adopted to investigate temporal changes in the three-dimensional (3D) vasculature of the healing callus. Quantitative evaluation protocols for vessel size distribution, total vessel volume, and volume fraction have also been established for comparative studies.

Nanoindentation is a relatively new technique that can achieve high-resolution characterization of material properties in musculoskeletal tissues. It has been shown to be an effective tool in describing changes in bone mineralization that result from disease and aging by quantifying the material's direct response to mechanical loading. Several studies have shown that the results of nanoindentation are highly sensitive to parameters such as sample preparation, loading protocol, indent location, and sample storage. This chapter describes the techniques for a successful nanoindentation protocol and addresses key technical considerations.

Bone-forming cells first fabricate a highly organized oollagen matrix, osteoid, which subsequently mineralizes. A variety of cell culture systems exist for osteogenic cells, yet none of these is optimal for the well-organized formation of a mineralized matrix. We have generated collagen substrates which have different degrees of fibrillar orientation, and have cultured osteogenic cells on these matrices. Osteoblast-rich cells isolated from 16 day chick embryos were cultured in micro-mass culture on the collagen sheets. Von Kossa-stained sections showed that highly oriented collagen matrix started to calcify in 6-7 days while a random fibrillar matrix did not mineralize even in 21 days. Mineral has been detected only within the collagen matrix with a narrow unmineralized region between the cells and the mineral like osteoid in vivo. The in vitro system described may serve as implantable materials facilitating in situ cell-mediated bone repair ultimately.