R axis bq

The crystallographic orientation of apatite crystallites was analyzed by the μXRD system (R-Axis BQ, Rigaku, Tokyo, Japan), which is equipped with a transmission-type optical system and an imaging plate (storage phosphors) (Fuji Film, Tokyo, Japan), at 9 points (regular intervals of 1/10 of the bone length along the longitudinal axis) of cortical bone in femurs as previously described [40 (link)] with a minor modification in that the incident beam was focused on a beam spot of 300 μm in diameter and diffraction data were collected for 180 sec. The preferential orientation degree of the BAp c-axis was assessed as the relative intensity ratio of the (002) diffraction peak to the (310) peak in the X-ray profile.

The degree of preferential apatite c‐axis orientation was analyzed by employing a microbeam X‐ray diffractometer (μXRD) (R‐Axis BQ; Rigaku Corporation) with a transmission optical system and Mo target. A Mo‐Kα line was generated at 50 kV and 90 mA. Double‐pinhole metal collimators with diameters of 200 and 800 μm were used, and μXRD measurements were carried out at points indicated by arrows shown in Fig. 7A, B. For the femur (4 mice), the incident beam was radiated vertically to the specimen at the center of the bone width. For the malleus (4 mice), to avoid X‐ray irradiation of the lamina, the beam center was displaced anteriorly, excluding the lamina.⁽²⁶ (link)
⁾ The diffracted beam was counted for 10 ks for malleus and 300 s for femur by an imaging plate (Fuji Film, Tokyo, Japan). The preferential orientation degree of the biological apatite c‐axis was evaluated by calculating the intensity ratio of (002)/(310), which is a dimensionless index.⁽¹⁴ (link), ²⁷ (link)
⁾ This value for randomly oriented apatite (National Institute of Standards and Technology, Standard Reference Material 2910: calcium hydroxyapatite) was confirmed to be 0.6. Thus, detected values >0.6 indicate an anisotropic apatite c‐axis orientation in the direction analyzed.

After the fracture testing, beam-shaped specimens with all types of tubule orientations, stored in HBSS at 4 °C, were taken to analyse the distribution of the preferential alignment of the c-axis of biological apatite using a microbeam X-ray diffraction system equipped with a transmission optical system (R-AXIS BQ, Rigaku, Japan)56 57 (link). Molybdenum-Kα radiation was generated at 50 kV and 90 mA (4.5 kW). The incident beam was collimated into a 300-μm circular spot by a double-pinhole metal collimator and radiated vertically onto the specimen. The X-ray diffraction data were recorded using an imaging plate (Fuji Film, Japan) for 300 s and the (002) and (310) reflections were identified in the X-ray profile. The diffraction data parallel and perpendicular to the long axis of the specimens were extracted (Fig. 4A) and the integrated intensity ratio of the (002) diffraction peak to the (310) diffraction peak was calculated. The intensity ratio corresponds to the degree of preferential alignment of the c-axis of the apatite crystallites58 (link).
The integrated intensity ratios between the directions of the specimens parallel and perpendicular to the long axis were compared by paired t-test. The correlations between the flexural strength and integrated intensity ratios were analysed mathematically using Analysis ToolPak.

The degree of apatite orientation in the femoral diaphysis was assessed using a micro-beam X-ray diffractometer system (R-Axis BQ, Rigaku, Tokyo, Japan) equipped with a transmission optical system. The incident beam (Mo-Kα) was irradiated perpendicular to the long axis of the bone at a tube voltage of 50 kV and a tube current of 90 mA. The preferential degree of the apatite c-axis orientation was determined as the relative intensity ratio of the (002) diffraction peak to the (310) peak in the X-ray profile [7 (link),12 (link)].

The degree of apatite orientation was analyzed using a microbeam X-ray diffractometer (µXRD) system (R-Axis BQ, Rigaku, Tokyo, Japan) equipped with a transmission optical system (Mo-Kα radiation). The incident beam was radiated vertically to the long axis of the bone at a tube voltage of 50 kV and a tube current of 90 mA. The degree of preferential orientation of the c-axis in the apatite crystals was determined as the relative intensity ratio of the (002) diffraction peak to the (310) peak in the X-ray profile. This was previously reported as a suitable index for evaluating apatite orientation [4 (link),5 (link)].