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We analyzed pedicle bone from roe bucks that had died around antler casting or shortly before or during the rutting period. Pedicles obtained around antler casting were highly porous and showed signs of intense osteoclastic activity that had caused the formation of an abscission line. Following the detachment of the antler plus a portion of pedicle bone, osteoclastic activity in the pedicles continued for some time, and new bone was deposited onto the separation plane of the pedicle stump, leading to partial pedicle restoration. Pedicles obtained around the rutting period were compact structures. The newly formed, often very large secondary osteons, which had filled the resorption cavities, exhibited a lower mineral density than the persisting older bone. The middle zones of the lamellar infilling frequently showed hypomineralized lamellae and enlarged osteocyte lacunae. This indicates a deficiency in mineral elements during the formation of these zones that occurred along with peak antler mineralization. We suggest that growing antlers and compacting pedicles compete for mineral elements, with the rapidly growing antlers being the more effective sinks. The competition between the two simultaneously mineralizing structures is probably more severe in Capreolus capreolus than in other cervids. This is because roe bucks regrow their antlers during late autumn and winter, a period of limited food and associated mineral supply. The pedicle is a heavily remodeled bone structure with distinct seasonal variation in porosity. Pedicle remodeling differs in several aspects from the normal bone remodeling process in the mammalian skeleton. [ABSTRACT FROM AUTHOR]

Laboratory microcomputed tomography (microCT) and synchrotron microCT imaged intact human second metacarpal bones (mc2) from two UK archeological sites: Ancaster (3rd to 4th century CE) and Wharram Percy (11th to 14th century CE). Two female mc2 were studied from each of three age at death cohorts (young, 18–29 years; middle, 30–49 years; old ≥50 years) along with a modern control mc2. The present investigation is complementary with an X‐ray scattering study of the same mc2 where the authors found no age‐at‐death‐related changes in carbonated apatite lattice parameters and found collagen D‐period peaks in the small angle regime in a minority of the mc2. This led the present authors to ask whether microCT could assign mc2 to the age cohort estimated by dental wear and whether material between bioerosion porosity and apparently free of diagenetic changes correlated with presence of strong D period peaks. Lab‐microCT derived values of bone volume fraction BV/TV (bone volume BV divided by total volume TV) for distal and proximal metaphyses provided age estimates that agree with those of dental wear. Cortical microstructure corroborated the BV/TV determination. Synchrotron microCT revealed significant diagenesis in all of the Wharram Percy and two of the Ancaster mc2; the resulting microstructural changes were attributed to microbial attack. The Ancaster mc2 whose microstructure matched that of the modern mc2 had D‐period peaks with intensities matching the modern bone. MicroCT with different voxel sizes was shown, therefore, to be very useful in age determination and in the assessment of 3D diagenetic changes. [ABSTRACT FROM AUTHOR]

High‐energy, wide‐angle x‐ray scattering (WAXS, x‐ray diffraction) and small‐angle x‐ray scattering (SAXS) were used to study intact human second metacarpal bones (mc2) from two UK archeological sites. A novel method correcting for irregular mass distribution was applied in these transmission geometry experiments done at beamline 1‐ID of the Advanced Photon Source. The authors asked whether there were age‐at‐death‐related changes in carbonated apatite (cAp) lattice parameters and whether SAXS could detect collagen D‐period peaks in the archeological mc2. For each of the two sites, Ancaster and Wharram Percy in England, six female mc2s were studied; for each site, two were from each of three age‐at‐death cohorts (young, 18–29 years; middle, 30–49 years; old ≥50 years) along with a modern control mc2. The Rietveld method was applied to the WAXS patterns to provide precise lattice parameter values. The cAp lattice parameters did not correlate with age‐at‐death estimated from dental wear. From WAXS and the 00.2 diffraction peak widths, four archeological mc2s possessed coherently scattering domain lengths (crystallite c‐axis sizes) that matched that of the modern mc2; SAXS revealed the same four archeological mc2 had D‐period peak intensities equivalent to that of the modern mc2. The other eight archeological mc2s had significantly larger crystallite sizes (than the modern mc2) and weak or absent D‐period peaks, differences attributed to diagenetic changes. Based on these data, the authors suggest that WAXS 00.2 peak width and SAXS D‐period peak intensity can be used with intact bones to select those likely to retain largely unaltered tissue nanostructure, which might be required for other analyses. Taken as a whole, the results suggest detecting age‐related deterioration in nanostructural features may be difficult in bone showing significant bioerosion. [ABSTRACT FROM AUTHOR]

Advanced functional materials often contain multiple phases which are (nano)crystalline and/or amorphous. The spatial distribution of these phases and their properties, including nanocrystallite size and shape, often drives material function yet is difficult to obtain with current experimental techniques. This article describes the use of diffraction scattering computed tomography, which maps wide-angle scattering information onto sample space, to address this challenge. The wide-angle scattering signal contains information on both (nano)crystalline and amorphous phases. Rietveld refinement of reconstructed diffraction patterns is employed to determine anisotropic nanocrystal shapes. The background signal from refinements is used to identify contributing amorphous phases through multivariate curve resolution. Thus it is demonstrated that reciprocal space analysis in combination with diffraction scattering computed tomography is a very powerful tool for the complete analysis of complex multiphase materials such as energy devices. [ABSTRACT FROM AUTHOR]

ABSTRACT Lung cancer is the second most prevalent cancer. Spinal metastases are found in 30-90% of patients with death attributed to cancer. Due to bony destruction caused by metastases, surgical intervention is often required to restore spinal alignment and stability. While some research suggests that BMP-2 may possess tumorigenic effects, other studies show possible inhibition of cancer growth. Thirty-six athymic rats underwent intraosseous injection of lung adenocarcinoma cells into the L5 vertebral body. Cells were pre-treated with vehicle control (Group A) or rhBMP-2 (Group B) prior to implantation. At 4 weeks post-implantation, in vivo bioluminescent imaging (BLI) was performed to confirm presence of tumor and quantify signal. Plain radiographs and microComputed Tomography (microCT) were employed to establish and quantitate osteolysis. Histological analysis characterized pathologic changes in the vertebral body. At 4 weeks post-implantation, BLI showed focal signal in the L5 vertebral body in 93% of Group A animals and 89% of Group B animals. Average tumor burden by BLI radiance was 7.43 × 103 p/s/cm2/sr (Group A) and 1.11 × 104 p/s/cm2/sr (Group B). Radiographs and microCT demonstrated osteolysis in 100% of animals showing focal BLI signal. MicroCT demonstrated significant bone loss in both groups compared to age-matched controls but no difference between study groups. Histological analysis confirmed tumor invasion in the L5 vertebral body. These findings provide a reliable in vivo model to study isolated spinal metastases from lung cancer. Statement of Clinical Significance: The data support the notion that exposure to rhBMP-2 does not promote the growth of A549 lung cancer spine lesions. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1274-1281, 2016. [ABSTRACT FROM AUTHOR]

Synchrotron X-ray scattering is used to measure average strains in the two main nanoscale phases of cortical bone - hydroxyapatite (HAP) platelets and collagen fibrils - under tensile loading at body temperature (37 °C) and under completely hydrated conditions. Dog-bone shaped specimens from bovine femoral cortical bone were prepared from three anatomical quadrants: anterio-medial, anterio-lateral, and posterio-lateral. The apparent HAP and fibrillar elastic moduli - ratios of tensile stress as applied externally and phase strains as measured by diffraction - exhibit significant correlations with the (i) femur quadrant from which the samples are obtained, (ii) properties obtained at the micro-scale using micro-computed tomography, i.e., microstructure, porosity and attenuation coefficient, and (iii) properties at the macro-scale using thermo-gravimetry and tensile testing, i.e., volume fraction and Young's modulus. Comparison of these tensile apparent moduli with compressive apparent moduli (previously published for samples from the same animal and tested under the same temperature and irradiation conditions) indicates that collagen deforms plastically to a greater extent in tension. Greater strains in the collagen fibril and concomitant greater load transfer to the HAP result in apparent moduli that are significantly lower in tension than in compression for both phases. However, tensile and compressive Young's moduli measured macroscopically are not significantly different during uniaxial testing. [ABSTRACT FROM AUTHOR]

The structure of an SiC-monofilament-reinforced Al-matrix composite was reconstructed using diffraction rings from these two phases. A 65 keV X-ray beam with 15 µm width (horizontal) and 150 µm length (vertical) was scanned across the specimen in 15 µm steps. A 2° rotation about the vertical rotation axis was used between projections, and filtered back projection reconstructions were created with 15 × 15 µm in-plane and 150 µm out-of-plane volume elements (voxels). The integrated intensities of the 11.0, 10.1 and 10.2 SiC and the 111, 200 and 220 Al diffraction rings were used to produce six independent reconstructions. The transmitted-intensity reconstruction agreed with that of higher resolution, absorption-contrast synchrotron microcomputed tomography. The Al reconstructions showed the effect of large grains, and the SiC reconstructions revealed the two microstructural zones in the fibers. [ABSTRACT FROM AUTHOR]

The use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in spine fusion has led to concerns regarding a potential accompanying inflammatory response. This study evaluates a combination therapy (TrioMatrix®; Pioneer Surgical, Inc., Marquette, MI) comprised of a demineralized bone matrix (DBM), hydroxyapatite, and a nanofiber-based collagen scaffold in a rodent spine fusion model. Thirty-six athymic rats that underwent a posterolateral intertransverse spinal fusion were randomly assigned to 1 of 5 treatment groups: absorbable collagen sponge alone (ACS, negative control), 10 µg rhBMP-2 on ACS (positive control), TrioMatrix®, Grafton® (Osteotech, Inc., Eatontown, NJ), and DBX® (Synthes, Inc., West Chester, PA). Both TrioMatrix® and rhBMP-2-treated animals demonstrated 100% fusion rates as graded by manual palpation scores 8 weeks after implantation. This rate was significantly greater than those of the ACS, Grafton®, and DBX® groups. Notably, the use of TrioMatrix® as evaluated by microCT quantification led to a greater fusion mass volume when compared to all other groups, including the rhBMP-2 group. T2-weighted axial MRI images of the fusion bed demonstrated a significant host response associated with a large fluid collection with the use of rhBMP-2; this response was significantly reduced with the use of TrioMatrix®. Our results therefore demonstrate that a nanocomposite therapy represents a promising, cost-effective bone graft substitute that could be useful in spine fusions where BMP-2 is contraindicated. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1812-1819, 2011 [ABSTRACT FROM AUTHOR]

Spatially resolved energy dispersive X-ray diffraction, using high-energy synchrotron radiation (∼35-80 keV), was used nondestructively to obtain phase composition profiles along the radii of cylindrical cement paste samples to characterize the progress of the chemical changes associated with sulfate attack on the cement. Phase distributions were acquired to depths of ∼4 mm below the specimen surface with sufficient spatial resolution to discern features less than 200 μm thick. The experimental and data analysis methods employed to obtain quantitative composition profiles are described. The spatial resolution that could be achieved is illustrated using data obtained from copper cylinders with a thin zinc coating. The measurements demonstrate that this approach is useful for nondestructively visualizing the sometimes complex transformations that take place during sulfate attack on cement-based materials. These transformations can be spatially related to microstructure as seen by computed microtomography. [ABSTRACT FROM AUTHOR]

Dentin is a hierarchically structured biomineralized composite material, and dentin's tubules are difficult to study in situ. Nano- CT provides the requisite resolution, but the field of view typically contains only a few tubules. Using a plate-like specimen allows reconstruction of a volume containing specific tubules from a number of truncated projections typically collected over an angular range of about 140°, which is practically accessible. Classical computed tomography (CT) theory cannot exactly reconstruct an object only from truncated projections, needless to say a limited angular range. Recently, interior tomography was developed to reconstruct a region-of-interest (ROI) fromtruncated data in a theoretically exact fashion via the total variation (TV) minimization under the condition that the ROI is piecewise constant. In this paper, we employ a TV minimization interior tomography algorithm to reconstruct interior microstructures in dentin fromtruncated projections over a limited angular range. Compared to the filtered backprojection (FBP) reconstruction, our reconstruction method reduces noise and suppresses artifacts. Volume rendering confirms the merits of our method in terms of preserving the interior microstructure of the dentin specimen. [ABSTRACT FROM AUTHOR]