Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Phosphorus-Implanted Glass for Radiotherapy: Effect of Implantation Energy (1999)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 82 (1999), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A chemically durable glass that contains a large amount of phosphorus is useful for in situ irradiation of cancers. It can be activated to be a β-emitter with a half-life of 14·3 d by using neutron bombardment. Microspheres of the activated glass that are injected to tumors can irradiate the tumors directly with β-rays without irradiating neighboring normal tissues. In the present study, P+ ions in various doses have been implanted into a pure silica glass in a plate form at 200 keV. Almost all the implanted phosphorus is present in the inner region of the glass rather than in the surface region, taking the form of phosphorus colloids for all the doses in the range of 5 × 1016-1 × 1018 cm-2. A large number of amorphous phosphorus colloid particles with diameters of 10-150 nm are formed in the silica glass that has been implanted with a dose of 1 × 1018 cm-2; these colloid particles are distributed widely in a layer that is centered at a depth of 200-250 nm. All the investigated glasses hardly release any phosphorus and silicon into water at a temperature of 95°C, even after 7 d. A silica glass that has been implanted with P+ ions at 200 keV with a dose of 1 × 1018 cm-2 is believed to be useful as a radiotherapy glass with sufficient phosphorus content and high chemical durability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1999.tb01817.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Novel Biomedical Materials Based on Glasses (1998)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 293 (Aug. 1998), p. 65-82 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/03/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.293.65.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Drug release from a novel self-setting bioactive glass bone cement containing cephalexin and its physicochemical propertiesThis study is part 2 of “A novel skeletal drug delivery system using self-setting bioactive glass bone cement.” (1995)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 33-38 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A novel device containing cephalexin as a model drug using a self-setting bioactive cement based on CaO—SiO2—P2O5 glass was investigated. The device consisted of 95 wt/wt% glass powders and 5 wt/wt% cephalexin powder hardened within 5 min after mixing with a phosphate buffer. After setting, in vitro drug release from homogeneous orheterogeneous drug-loaded cement pellets in a simulated body fluid (SBF) at pH 7.25 and 37°C continued for over 4 weeks. The hardened cement gradually formed low-crystallinity hydroxyapatite with high bioactivity in hard bone tissue and reduced in volume by about 5% during dissolution testing in SBF. Consequently, 30% of the loaded drug was squeezed from the cement system at the initial stage of the drug release, and the remainder released more slowly. Because the heterogeneous system consisting of the cement and drug-loaded pellet avoided the drug-squeezing effect, it showed a longer drug release term than the homogeneous drug-loaded cement. The heterogeneous system using the hardened cement after soaking in SBF at 37°C for 10 days showed very slow drug release at the initial stage because it completely avoided the drug-squeezing effect, and the release was a zero-order pattern. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820290106
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Preparation of bioactive Ti and its alloys via simple chemical surface treatment (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 32 (1996), S. 409-417 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A simple chemical method was established for inducing bioactivity of Ti and its alloys. When pure Ti, Ti-6Al-4V, Ti-6Al-2Nb-Ta, and Ti-15Mo-5Zr-3Al substrates were treated with 10M NaOH aqueous solution and subsequently heat-treated at 600°C, a thin sodium titanate layer was formed on their surfaces. Thus, treated substrates formed a dense and uniform bonelike apatite layer on their surfaces in simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma. This indicates that the alkali- and heat-treated metals bond to living bone through the bonelike apatite layer formed on their surfaces in the body. The apatite formation on the surfaces of Ti and its alloys was assumed to be induced by a hydrated titania which was formed by an ion exchange of the alkali ion in the alkali titanate layer and the hydronium ion in SBF. The resultant surface structure changed gradually from the outermost apatite layer to the inner Ti and its alloys through a hydrated titania and titanium oxide layers. This provides not only the strong bonding of the apatite layer to the substrates but also a uniform gradient of stress transfer from bone to the implants. The present chemical surface modification is therefore expected to allow the use the bioactive Ti and its alloys as artificial bones even under load-bearing conditons. © 1996 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Apatite formation on silica gel in simulated body fluid: Its dependence on structures of silica gels prepared in different media (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 33 (1996), S. 145-151 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: It has been shown that the prerequisite for glasses and glass-ceramics to bond to living bone is the formation of a layer of biologically active bonelike apatite on their surfaces. The hydrated silica formed on the surfaces of glasses and glass-ceramics plays an important role in nucleating the apatite. In the present study, the structure of the hydrated silica responsible for the apatite nucleation was investigated in an accellular simulated body fluid with ion concentrations nearly equal to those of human blood plasma. Three kinds of porous silica gels were prepared by hydrolysis and polycondensation of tetraethoxysilane in pure water or in aqueous solution containing polyethylene glycol or polyacrylic acid. The silica gels prepared in aqueous solution containing polyethylene glycol or polyacrylic acid had micron-size interconnected pores, whereas the gel prepared in pure water did not. All the gels contained a large volume of nanometer-size pores, almost the same amounts of silanol groups and D2 defect, and showed a high dissolution rate of the silica. Despite this, only the gel prepared in the solution containing polyethylene glycol formed the apatite on its surface in the simulated body fluid. This indicates that only a certain type of structural unit of the silanol group is responsible for the apatite nucleation. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Direct bone formation on alumina bead composite (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 37 (1997), S. 554-565 
    Details
    ISSN: 0021-9304
    Keywords: alumina ; Bis-GMA ; composite ; mechanical properties ; osteoconduction ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: We have developed a composite (designated ABC), consisting of alumina bead powder as an inorganic filler and bisphenol-a-glycidyl methacrylate (Bis-GMA)-based resin as an organic matrix, which allows direct bone formation on its surface in vivo. Alumina bead powder was manufactured by fusing crushed α-alumina powder and quenching it. The beads took spherical form 3 μm in average size. According to powder X-ray diffraction and Fourier transform infrared spectroscopy, the alumina bead powder was composed of amorphous and δ-crystal phases of alumina in its main crystal structure. Fused-quenched silica glass-filled composite (SGC) was used as a control. The proportion of filler added to the composites was 70% w/w. Mechanical testing of the ABC indicated that it would be strong enough for use under weight-bearing conditions. No apatite formation was detected on the surfaces of either composite after soaking in simulated body fluid for 28 days in vitro. Histological examination of rat tibiae for up to 8 weeks revealed that ABC bonded to bone directly via a layer of calcium, phosphorus, and alumina with no interposed soft-tissue layer. Moreover, the amount of bone directly apposed to the ABC surface increased with time, whereas with SGC there was poor direct bone formation even at 8 weeks. The precise mechanism of direct bone formation on ABC is as yet unknown but it is possible that changes in the crystallinity of alumina, which is known to be highly biocompatible, contribute to its excellent osteoconductivity in vivo. Although bioactive materials such as Bioglass® or apatite and wollastonite-containing glass-ceramic have previously been reported to form bone-like apatite on their surfaces under acellular conditions via simple chemical reactions, ABC does not have such characteristics, and presenting favorable conditions for osteoconduction and tissue calcification may lead to direct bone formation on its surface in vivo. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 554-565, 1997.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 7
    Electronic Resource
    Electronic Resource
    Preparation of radiotherapy glass by phosphorus ion implantation at 100 keV (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 38 (1997), S. 342-347 
    Details
    ISSN: 0021-9304
    Keywords: phosphorus ; ion implantation ; silica glass ; radiotherapy ; chemical durability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A chemically durable glass containing a large amount of phosphorus is useful for in situ irradiation of cancers. It can be activated to be a β emitter (half-life of 14.3 days) by neutron bombardment. Microspheres of the activated glass injected into the tumors can irradiate the tumors directly with β rays without irradiating neighboring normal tissues. In the present study a P+ ion was implanted into a pure silica glass in a plate form at 100 keV in order to find the fundamental conditions for obtaining such a glass. Little phosphorus was present in the surface region, at least to a depth of 2.4 nm for doses of 5 × 1016 and 1 × 1017 cm-2, whereas an appreciable amount of it was distributed on the glass surface and a part of it was oxidized for doses above 5 × 1017 cm-2. The glasses implanted with doses of 5 × 1016 and 1 × 1017 cm-2 hardly released the P and Si into water at 95 °C, even after 7 days, whereas the glasses implanted with doses above 5 × 1017 cm-2 released appreciable amounts of these elements. Implantation energies of 20 and 50 keV (even at doses of 5 × 1016 and 1 × 1017 cm-2, respectively), formed oxidized phosphorus on the glass surfaces and gave appreciable releases of the P and Si into the hot water. This indicates that a chemically durable glass containing a larger amount of phosphorus could be obtained if a P+ ion is implanted at higher energies to localize in a deeper region of the glass surface. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 38: 342-347, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 8
    Electronic Resource
    Electronic Resource
    Bone bonding ability of an apatite-coated polymer produced using a biomimetic method: A mechanical and histological study in vivo (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 31 (1996), S. 487-494 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A 20-μm thick apatite layer was coated onto polyethersulfone (PES) rectangular plates by soaking them in simulated body fluid containing CaO-SiO2 based glass powder. Coated and uncoated PES plates (10 × 15 × 1.5 mm) were implanted in the tibiae of rabbits, which were sacrificed 8, 16, and 30 weeks thereafter, and the samples were examined histologically using contact microradiography (CMR), Giemsa surface staining, and a scanning electron microscope connected to an electron probe microanalyzer (SEM-EPMA). The tensile failure loads at the bone/implant interfaces were determined using the detaching test. The histological examinations showed excellent bone apposition on coated PES and the sign of degradation of the apatite layer at remodeling lacunae. The apatite layer underwent complete resorption and was replaced by bone in most areas of the bone/implant interface after 30 weeks. Bone did not bond directly to uncoated PES after each follow-up period. The failure loads between bone and coated PES at 8, 16, and 30 weeks after implantation were 1.17 ± 0.35, 2.36 ± 0.53, and 1.45 ± 0.48 kg, respectively. Those between bone and uncoated PES were nearly 0 kg at each postimplantation period. Failure during the detaching test occurred at the bone/apatite interface or near it after 8 weeks. After 16 weeks, it usually occurred at the apatite/PES interface or near it, and occasionally in the middle of the apatite layer. The apatite layer was hardly detected at the failured interface after 30 weeks. In this study, an apatite-coated PES produced using a biomimetic method was demonstrated to bond directly to bone without any intervening soft tissue, which indicates that this material possesses excellent bioactivity. © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 9
    Electronic Resource
    Electronic Resource
    Bioactive bone cement: Comparison of apatite and wollastonite containing glass-ceramic, hydroxyapatite, and β-tricalcium phosphate fillers on bone-bonding strength (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 42 (1998), S. 223-237 
    Details
    ISSN: 0021-9304
    Keywords: bioactive bone cement ; apatite-wollastonite-glass-ceramic ; hydroxyapatite ; β-tricalcium phosphate; bone-bonding strength ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A study was conducted to compare the bone-bonding strengths of three types of bioactive bone cement, consisting of either apatite- and wollastonite-containing glass-ceramic (AW-GC) powder, hydroxyapatite (HA) powder, or β-tricalcium phosphate (β-TCP) powder as an inorganic filler and bisphenol-a-glycidyl methacrylate (Bis-GMA) based resin as an organic matrix. Seventy percent (w/w) filler was added to the cement. Rectangular plates (10 × 15 × 2 mm) of each cement were made and abraded with #2000 alumina powder. After soaking in simulated body fluid for 2 days, the AW cement (AWC) and HA cement (HAC) formed bonelike apatite over their entire surfaces, but the TCP cement (TCPC) did not. Plates of each type of cement were implanted into the tibial metaphyses of male Japanese white rabbits, and the failure loads were measured by a detaching test at 10 and 25 weeks after implantation. The failure loads of AWC, HAC, and TCPC were 3.95, 2.04, and 2.03 kgf at 10 weeks and 4.36, 3.45, and 3.10 kgf at 25 weeks, respectively. The failure loads of the AWC were significantly higher than those of the HAC and TCPC at 10 and 25 weeks. Histological examination by contact microradiogram and Giemsa surface staining of the bone-cement interface revealed that all the bioactive bone cements were in direct contact with bone. However, scanning electron microscopy and energy-dispersive X-ray microanalysis showed that only AWC had contacted to the bone via a Ca-P rich layer formed at the interface between the AW-GC powder and the bone, which might explain its high bone-bonding strength. Neither the HAC nor the TCPC contacted the bone through such a layer between each powder and the bone, although the HAC and TCPC directly contacted with bone. Our results indicate that all three types of abraded and prefabricated cement have bonding strength to bone, but AWC has superior bone-bonding strength compared to HAC and TCPC. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 223-237, 1998.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 10
    Electronic Resource
    Electronic Resource
    Effect of polymerization reaction inhibitor on mechanical properties and surface reactivity of bioactive bone cementNo benefit of any kind will be received either directly or indirectly by the authors. (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 43 (1998), S. 140-152 
    Details
    ISSN: 0021-9304
    Keywords: bioactive bone cement ; inhibitor ; accelerator ; mechanical properties ; bioactivity ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: We introduced an inhibitor to the polymerization reaction of bioactive bone cement (AWC) consisting of MgO - CaO - SiO2 - P2O5 - CaF2 apatite and wollastonite containing glass-ceramic powder and bisphenol-α-glycidyl methacrylate based resin, together with an increased amount of accelerator but without any prolongation of its setting time in order to improve the degree of polymerization and decrease the amount of incompletely polymerized monomers on the cement surface. A comparison was made between the AWC containing the inhibitor [AWC(I+)] and the AWC without it [AWC(I-)] with regard to setting parameters, mechanical properties, and surface reactivity in vitro and in vivo. The proportion of glass-ceramic powder added to the AWC was 70% (w/w). The total amount of heat generation and the peak temperature of the AWC(I+) during polymerization were slightly greater than those of the AWC(I-). The mechanical strength of AWC(I+) was higher than that of the AWC(I-) under wet conditions. In simulated body fluid, the width of the Ca-P rich layer on the surface of the AWC(I+) was less than that on the AWC(I-) after 28 days of immersion, although the rate of apatite formation on the top surface of the AWC(I+) was almost identical to that on the AWC(I-) surface. Histological examination using rat tibiae up to 26 weeks revealed that the bioactivity of the AWC(I+) was equivalent to that of the AWC(I-). Scanning electron microscopy and energy-dispersive X-ray microanalysis demonstrated that the Ca-P rich layer in the AWC(I+) was significantly narrower than that in the AWC(I-) at the same time points. These results indicate that introduction of the inhibitor improved the mechanical properties of the AWC and made the Ca-P rich layer narrower, but it had no adverse effect on bioactivity. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 43: 140-152, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...