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26
Dec
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- Article wrote by
Daniel Amsel
Novelties in measurement programs Speed of measurement by densitometric techniques in children is of great importance, because it is hard to keep children motionless during the performance. However, utilization of speeding up measurement as fan beam technique has still some disadvantages enforcing the needs of its further evaluation and cross-calibration. For accurate determination of bone [...]
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25
Dec
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- Article wrote by
Daniel Amsel
The first generation of QUS systems characterized the bone tissue with the use of two relevant parameters: the speed of sound (SOS) and the attenuation of the signal [broadband ultrasound attenuation (BUA)]. The amount of attenuation depends on the structure, the specific acoustic properties of the medium, and the wavelength the ultrasound signal used. In [...]
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24
Dec
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- Article wrote by
Daniel Amsel
Introduction The clinical assessment of bone strength and fracture risk as well in children as in adults has always been a difficult challenge for its practical solution. The reason for that seems to be matter of both – focus and target. The problem concerns not only how or how well to measure, but essentially what [...]
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23
Dec
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- Article wrote by
Daniel Amsel
Infrared microspectroscopic analysis of bone tissue from animal models and humans at equivalent anatomical locations gave great insight to the role of bone quality in determining bone strength. It became feasible to conclusively show differences in bone mineral maturity between normal and osteoporotic bone at equivalent anatomical locations. Even more revealing was the analysis of [...]
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22
Dec
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- Article wrote by
Daniel Amsel
Molecular bonds are not stationary, but rather undergo motion such as twisting, bending, stretching, rotation and vibration. When irradiated with infrared radiation, these vibrational motions absorb at specific wavelengths, characteristic of the overall configuration of the atoms, and representative of specific functional groups. Moreover, through detailed analysis of the absorption wavelengths, information may be deduced [...]
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21
Dec
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- Article wrote by
Daniel Amsel
Bone mineral is a poorly crystalline hydroxyapatite [Ca5(PO4)3OH] phase. Ion substitutions are abundant. For example, Na+1, and Mg+2 are substituting Ca+2 ions, HPO4-2 ions substituting the phosphate ions, Cl-1 and F-1 substituting OH-1, and CO3-2 substituting for either phosphate or hydroxyl groups. Once mineral is deposited in bone by osteoblasts, it is not a static [...]
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20
Dec
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- Article wrote by
Daniel Amsel
Bone Bone is a composite material, consisting mainly of mineral and collagen. In normal humans, cortical bone constitutes approximately 80% of the human skeletal mass and trabecular bone approximately 20%. Bone surfaces may be undergoing formation or resorption, or they may be inactive. These processes occur throughout life in both cortical and trabecular bone. Bone [...]