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  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 13 (1980), S. 380-384 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A method is presented for improving the accuracy of the determination of peak positions from step-scanned X-ray powder diffraction data. This method is intended to be used in situations where the nature of the sample produces broad asymmetric peaks with a low peak-to-background ratio. A Fourier series is fitted to the experimental step-scan observations and the peak position is calculated from this functional representation. The method has been tried on the mineral apatite from biological sources, mainly bone, where ionic substitutions affect the cell parameters.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 25 (1978), S. 99-104 
    ISSN: 1432-0827
    Keywords: Low temperature ashing ; Enamel ; Bone mineral ; Gas trapping ; Free radicals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Low temperature ashing by excited gas (LTA) causes crystallographic and paramagnetic alterations of the human bone and tooth enamel mineral. On the one hand, LTA induces variations of thea lattice parameter. These variations depend upon the nature of the gas used, but are little affected by its degree of excitation. Trapping of gas molecules in the crystal structure is demonstrated. On the other hand, LTA produces two preponderant paramagnetic centers in bone and enamel samples at 20°C. Their inorganic origin is clearly indicated. One of the two radicals has been identified as O3 − (g1=2.002, g2=2.010, g3=2.016) and the other as CO 3 3− (g‖=1.996, g⊥=2.003). Variations of thea lattice parameter and trapping of paramagnetic gas species do not seem to be directly related.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1433-2965
    Keywords: Bisphosphonate ; Bone chemistry ; Bone mechanical properties ; Bone mineralization ; Dog
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The goal of this study was to evaluate the effect of 1 year of APD administration on bone mineralization and bone mineral chemistry in the dog. Disodium pamidronate (APD) was given orally by gavage to mature beagle dogs at doses of 0, 2.5, 12.5 and 25.0 mg/kg per day (0.1% concentration for 12 months) as part of a long-term toxicity study. The os ilium and a vertebra were used to determine the mineralization profile and, subsequently, each density fraction was analysed chemically. Theribs were used to determine lattice parameters of the apatite crystal size using X-ray diffraction. The sternum was used to determine selected morphometric parameters using image analysis of specimen X-ray films and subsequently to determine mechanical properties using velocity-of-sound techniques. We found that for both the ilium and the vertebrae there was a significant shift of the mineralization profile towards greater density in a dose-related manner. This effect levelled off with the highest dose because the shift in mineralization profile correlated better with the square root of the dose than with the dose. Together with data on crystal size, which show an increase in lattice parameters and a decrease in crystal size with dose, our data lead us to believe that long-term administration of APD leads to an increase in bone mineralization without major changes in bone chemistry of Ca, Mg, and P and with a decrease in bone apatite crystal size. The image analysis shows a dose-related increase in trabecular bone volume and thickness. Furthermore, the elastic modulus of the trabecular bone increased linearly with the square root of the administered dose. These findings suggest that APD treatment increases the packing density of bone crystals and may decrease the solubility of bone mineral.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 55 (1994), S. 288-294 
    ISSN: 1432-0827
    Keywords: Bisphosphonate ; Bone mineralization, structure, mechanical properties ; Dog ; Recovery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The goal of this study was to find out if bone can recover after long-term administration of bisphosphonate. Disodium pamidronate (APD) was given orally by gavage to mature beagle dogs at doses of 0, 2.5, 12.5, and 25 mg/kg/day for 1 year (0.1% concentration) and the animals were allowed to recover for another year. At sacrifice, the os ilium was used to determine bone mineralization profile and, subsequently, each density fraction was analyzed chemically. The ribs were used to determine the lattice parameters and the size of the apatite crystals of bone. The sternum was used to determine selected morphometric parameters using image analysis of specimen X-ray films and, subsequently, to determine bone mechanical properties using a 3-point bending technique. We found that the 12.5 and 25 mg/kg/day doses exhibit a significant shift towards greater mineralization versus control, whereas the lower dose (2.5 mg/kg/day) was indistinguishable from the controls. The lattice parameters and crystal size of bone apatite remained unchanged. The image analysis shows a dose-related increase in trabecular volume and thickness. The connectivity increased with dose but the anisotropy of bone remained unchanged. Both the elastic modulus and the maximum stress of bone remain unaffected by APD. We conclude that when dogs are treated with APD for 1 year, their bones can reestablish their physical-chemical characteristics (mineralization profile, chemistry, and crystal size/strain) after 1 year of recovery, provided that the treatment doss is 2.5 mg/kg/day. In addition, the mechanical properties of the bone remained unaffected and the gains in trabecular volume and thickness are maintained.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0827
    Keywords: Key words: Ewe — Ovariectomy — Calcitonin — Bone quality — Crystallography.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. The aim of this study was to evaluate the effect of intermittent calcitonin on femoral bone quality in adult ewes from the time of ovariectomy. Six months after the start of the experiment, bone density measurements and mechanical testing (torsion and resonant frequency analysis of the diaphysis and compression of an excised trabecular bone cylinder from the femoral neck) were performed in sham-control and ovariectomized (OVX) ewes treated with placebo or salmon calcitonin (50 or 100 units, 3 times/week). Crystallinity of bone was evaluated by measuring X-ray diffraction line broadening. After OVX, a nonsignificant bone loss was found at all measured sites in the femur (−3 to −9%) together with a decreased biomechanical competence in the trabecular bone (compressive strain −28%, P 〈 0.05). Treatment with salmon calcitonin, 50 or 100 IU subcutaneously three times a week from the time of ovariectomy, resulted in a significant dose-dependent preservation of bone strength in the trabecular bone of the femoral neck compared with OVX. No adverse effects of calcitonin were observed on bone crystal composition as assessed by diffractiometry. We conclude that in adult ewes intermittent calcitonin treatment from the time of OVX was associated with a significant preservation of cancellous bone strength and strain in trabecular bone of the femoral neck, without affecting crystalline properties of bone.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0827
    Keywords: Key words: Bone matrix — Collagen — Aging — FTIR.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. In order to determine the effects of age on bone quality, human bone tissue taken from adult subjects deceased from violent death was analyzed by means of fast Fourier transform infrared spectrophotometry (FTIR) in the Diffuse Reflectance mode (DR). This technique allows the characterization of both the mineral and organic parts of bone in a nondestructive manner. Only the organic part is discussed in this report. A quantitative change in the entire organic part of bone tissue is observed with the aging of subjects. The effects of these changes on bone strength were not measured.
    Type of Medium: Electronic Resource
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