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  • 1
    Electronic Resource
    Electronic Resource
    In situ expression of RANKL, RANK, osteoprotegerin and cytokines in osteoclasts of rat periodontal tissue (2004)
    Oxford, UK : Munksgaard International Publishers
    Journal of periodontal research 39 (2004), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objectives:  This study examined the in situ expression of receptor activator of nuclear factor-κB ligand (RANKL), receptor activator of nuclear factor-κB (RANK), osteoprotegerin, interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) in the osteoclasts of rat periodontal tissue.Background:  In periodontal disease, osteoclasts cause resorption of the alveolar bone. The function of osteoclasts is regulated by interaction with periodontal ligament cells (PDLs). Furthermore, various kinds of molecules such as RANKL, RANK, osteoprotegerin, IL-1β and TNFα are known to be related to the osteoclasts differentiation and function. It is therefore important to observe the expression of RANKL, RANK, osteoprotegerin and cytokines in osteoclasts and PDLs.Methods:  Four-week-old Wistar rats were used. Tooth movement was performed by the Waldo method, and the pathological bone resorption was induced. The demineralized maxillae and mandiblae were embedded with paraffin. In situ hybridization was performed to detect RANKL, RANK, osteoprotegerin, IL-1β, and TNFα mRNAs in osteoclasts and other cells using the specific RNA probes, respectively.Results:  Both RANKL and RANK were concomitantly expressed in some osteoclasts. RANKL was also positive in osteoblasts and PDLs. No IL-1β- and TNFα-positive osteoclast was noted. The positive signals of osteoprotegerin were detected in almost all osteoblasts, PDLs and odontoblasts. No osteoprotegerin-positive osteoclasts were observed. The number and the distribution pattern of RANKL- and RANK-expressing osteoclasts changed when orthodontic excessive force was applied to periodontal tissue. In addition, IL-1β and TNFα were shown to be expressed in osteoclasts under pathological status.Conclusion:  These findings suggest that an autocrine mechanism of RANKL–RANK exists in osteoclast, which is heightened in the pathological conditions. Furthermore, the autocrine mechanism of IL-1β and TNFα is also provided in osteoclast under pathological condition. These autocrine mechanisms therefore seem to regulate the osteoclast function in both physiological and pathological conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.2004.00699.x
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  • 2
    Electronic Resource
    Electronic Resource
    Microstructure of ceramic coating on titanium surface as a result of hydrothermal treatment (2000)
    Springer
    Journal of materials science 11 (2000), S. 751-755 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Hydroxyapatite coating on commercially pure titanium has been produced by a biomimetic method in order to improve osteointegration for medical implant purposes. A specific chemical treatment by etching titanium substrate with different concentrations of NaOH aqueous solution at 130 °C in an autoclave, followed by heat treatment at 600 °C was selected to obtain an activated titanium substrate. The microporous surface obtained has allowed the nucleation and growth of a calcium phosphate layer by soaking the substrate in a simulated body fluid (SBF). Scanning electron microscopy (SEM) together with energy dispersive analyzer for X-ray (EDS), X-ray diffraction (XRD) as well as Fourier transform infrared spectroscopy (FT-IR) were employed to evaluate the hydroxyapatite coating. A homogeneous structure coating without cracks defined the chemical treatment condition of the substrate. © 2000 Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008984030540
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  • 3
    Electronic Resource
    Electronic Resource
    Growth process for fractal polymer aggregates formed by perfluorooctyltrimethoxysilane. Time-resolved small-angle X-ray scattering study (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 293-300 
    Details
    ISSN: 1435-1536
    Keywords: Key words Perfluorooctyl-trimethoxysilane ; Mass fractal ; Small-angle X-ray scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The acid-catalyzed condensation reaction of perfluorooctyltrimethoxysilane (PFOS) and n-octyltrimethoxysilane (OTMS) in ethanol has been followed by time-resolved synchrotron radiation small-angle X-ray scattering (SAXS) on a short time scale. SAXS curves for PFOS and OTMS have been interpreted as arising from mass fractals with D f=2 (PFOS) and D f=1.7 (OTMS). The time dependence of the apparent radius of gyration, obtained from the Guinier plots, showed that the growth of fractal precursors occurs in a two-step process within 2 h for PFOS and within 1.5 h for OTMS, in which small clusters involving monomers, dimers and trimers are formed in the initial step and formation of larger clusters occurs in the second step. Furthermore, it has been suggested that the hydrophobicity and lipophobicity of the bulky alkyl groups may also contribute to the formation of these giant aggregates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050517
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  • 4
    Electronic Resource
    Electronic Resource
    Time-resolved near-infrared and two-dimensional near-infrared correlation spectroscopic studies on polymerization of the silane coupling agent perfluorooctyltrimethoxysilane (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 946-953 
    Details
    ISSN: 1435-1536
    Keywords: Key words Time-resolved near infrared ; Two-dimensional correlation ; Perfluorooctyltri methoxysilane ; Condensation water, alcohol and silanol behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  The polymerization behavior of perfluorooctyltrimethoxysilane (PFOS) in ethanol, which is acid-catalyzed by 0.25 M HCl, has been examined using time-resolved near-IR and 2D near-IR correlation spectra. In the time-resolved near-IR spectra, the bands at 5164 and 4825 cm−1 have been assigned to the combination bands of water and ethanol OH groups, respectively. It has been found that the absorbance variation of the two near-IR bands occurs in a two-step process. The absorbance of the 5164 cm−1 band rapidly decreases in the initial step but increases exponentially in the second step, while that of the 4825 cm−1 band rapidly increases both in the initial step and, exponentially, in the second step. These results indicate that the time-dependent absorbance variation of the two near-IR bands reflects the polymerization process of PFOS, in which consumption and release of water molecules and release of methanol in the two-step process occur as a consequence of the acid-catalyzed hydrolysis of methoxy groups and the formation of silanols (SiOH) to form a siloxane bond. It has also been found that this polymerization process is distinctly reflected in the 2D near-IR correlation spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960000345
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  • 5
    Electronic Resource
    Electronic Resource
    Time-resolved near-infrared and two-dimensional near-infrared correlation spectroscopic studies of the polymerization process of silane coupling agents. Dynamic behavior of water molecules in the 3-aminopropyltriethoxysilane–ethanol–water system (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1070-1084 
    Details
    ISSN: 1435-1536
    Keywords: Key words Time-resolved near-infrared ; Two-dimensional correlation ; 3-Aminopropyltriethoxysilane ; Condensation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The polymerization behavior of 3-aminopropyltriethoxysilane, a process initiated by water molecules, has been examined using time-resolved near-IR and 2D near-IR correlation spectra. By deconvolution of the time-resolved near-IR spectra, the existence of the component bands at 5189, 5265 and 5300 cm−1, whose intensities decrease markedly as the reaction proceeds, has been confirmed in the 5000–5400 cm−1 region. The band at 5189 cm−1 has been assigned to water molecules, while those at 5265 and 5300 cm−1 have been assigned to the strongly and weakly associated silanol groups, respectively. The kinetics of the hydrolysis of the ethoxy groups and of the formation of a siloxane bond have been analyzed using the time-dependent integral intensities of these three bands and the mechanisms of the reactions have been discussed. Evidence for this polymerization process is also clearly evident in the 2D near-IR correlation spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960000371
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  • 6
    Electronic Resource
    Electronic Resource
    Tensile creep behavior of 3-D woven Si-Ti-C-O fiber/SiC-based matrix composite with glass sealant (2000)
    Springer
    Journal of materials science 35 (2000), S. 785-793 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The present work investigates the tensile creep behavior (deformation and rupture) at 1100–1300°C in air of a 3-D woven Si-Ti-C-O (Tyranno™) fiber/SiC-based matrix composite with and without glass sealant. The composite contained Si-Ti-C-O fibers with an additional surface modification in order to improve interface properties. Although a significant decrease in tensile strength was observed in the unsealed composite beyond 1000°C in air (and attributed to oxidation of the fiber/matrix interface), the composite with glass sealant possessed excellent mechanical properties for short-term (〈1 hr.) exposure in air. In this study, tensile creep testing was conducted at 1100–1300°C in air and the effect of glass sealant on medium- and long-term strength was investigated. In addition, chemical stability of the glass sealant was evaluated by X-ray diffraction analysis (XRD) and energy dispersive X-ray spectrometer (EDS). The creep rupture behavior of the composite with glass sealant under long-term exposure is suggested to depend on several factors including decomposition, evaporation, and crystallization of the glass sealant material, in addition to the applied stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004796615811
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