Nippon Electric Glass

About: Nippon Electric Glass is a company organization based out in Ōtsu, Japan. It is known for research contribution in the topics: Flat glass & Layer (electronics). The organization has 657 authors who have published 719 publications receiving 8765 citations.

Bone bonding behavior of three kinds of apatite containing glass ceramics

Abstract: We have produced three kinds of apatite-containing glass ceramics of the same chemical composition: MgO (4.6), CaO (44.9), SiO2 (34.2), P2O5 (16.3), CaF2 (0.5) (in weight ratio). They contain different crystal combinations and have different mechanical properties. The first glass ceramic (A–;GC) was prepared by heating a glass plate to 870°C. It contains only oxy- and fluoroapatite (35 wt%). The second glass ceramic (A–W–GC), and the third (A–W–CP–GC), were prepared by heating glass powder compacts to 1050°C and 1200°C, respectively. A–W–GC contains oxyapatite and fluoroapatite (Ca10(PO4)6(O,F2)) (35 wt%) and β-wollastonite (40 wt%). A–W–CP–GC contains oxyapatite and fluoroapatite (20 wt%), β-wollastonite (CaO·SiO2) (55 wt%), and β-whitlockite (3CaO·P2O5) (15 wt%). The bending strengths of A–;GC, A–W–GC, and A–W–CP–GC were 88MPa, 178MPa, and 213MPa, respectively, in air. Rectangular ceramic plates (15mm × 10mm × 2mm) were implanted into a rabbit tibia. Ten and 25 weeks after implantation, the segment of tibia with implant was excised for examination. The segment was held by a special jig and the traction breaking load (failure load) was measured by an autograph. A–;GC showed a lower load than A–W–GC and A–W–CP–GC. The loads for A–W–GC and A–W–CP–GC were almost equal. The failure loads did not change significantly between 10 and 25 weeks for any of the materials. The interface was examined by Giemsa surface staining, contact micro-radiography, and SEM-EPMA. Giemsa surface staining and CMR revealed direct bonding between the materials and the bone for all the three materials. SEM-EPMA showed that Si and Mg content decreased, Ca content did not change, and P content increased at the reaction zone between all three glass ceramics and bone. This was observed at 10 weeks, as well as at 25 weeks, after implantation. The reaction zone was narrowest with A–;GC, wider with A–W–GC, and widest with A–W–CP–GC.

Alkali-free glass substrate

Abstract: An alkali-free glass substrate containing, by mass percent, 50-70% of SiO2, 10-25% of Al2O3, 5-20% of B2O3, 0-10% of MgO, 0-15% of CaO, 0-10% of BaO, 0-10% of SrO and 0-5% of ZnO, also containing SnO2 and/or Sb2O3 and having a B-OH value of at least 0.485/mm.

Bioactive polymethyl methacrylate‐based bone cement: Comparison of glass beads, apatite‐ and wollastonite‐containing glass–ceramic, and hydroxyapatite fillers on mechanical and biological properties

Abstract: A new bioactive bone cement (designated GBC) consisting of polymethyl methacrylate (PMMA) as an organic matrix and bioactive glass beads as an inorganic filler has been developed. The bioactive beads, consisting of MgO-CaO-SiO(2)-P(2)O(5)-CaF(2) glass, have been newly designed, and a novel PMMA powder was selected. The purpose of the present study was to compare this new bone cement GBC's mechanical properties in vitro and its osteoconductivity in vivo with cements consisting of the same matrix as GBC and either apatite- and wollastonite-containing glass-ceramic (AW-GC) powder (designated AWC) or sintered hydroxyapatite (HA) powder (HAC). Each filler added to the cements amounted to 70 wt %. The bending strength of GBC was significantly higher than that of AWC and HAC (p < 0.0001). Cements were packed into intramedullar canals of rat tibiae in order to evaluate osteoconductivity as determined by an affinity index. Rats were sacrificed at 2, 4, and 8 weeks after operation. An affinity index, which equaled the length of bone in direct contact with the cement expressed as a percentage of the total length of the cement surface, was calculated for each cement. At each time interval studied, GBC showed a significantly higher affinity index than AWC or HAC up to 8 weeks after implantation (p < 0.03). The value for GBC increased significantly with time up to 8 weeks (p < 0.006). The handling property of GBC was comparable with that of PMMA bone cement. Our study revealed that the higher osteoconductivity of GBC was due to the higher bioactivity of the bioactive glass beads at the cement surface and the lower solubility of the new PMMA powder to MMA monomer. In addition, it was found that the smaller spherical shape and glassy phase of the glass beads gave GBC strong enough mechanical properties to be useful under weight-bearing conditions. GBC shows promise as an alternative with improved properties to the conventionally used PMMA bone cement.

SEM‐EPMA observation of three types of apatite‐containing glass‐ceramics implanted in bone: The variance of a Ca‐P‐rich layer

Abstract: The progressive changes of a Ca-P-rich layer between bone and three types of apatite-containing glass-ceramics of the same chemical composition: MgO 4.6, CaO 44.9, SiO2 34.2, P2O5 16.3, CaF2 0.5 (in weight ratio) were examined. Plates (15 mm × 10 mm × 2 mm, mirror surface) containing apatite (35 wt%) (designated A-GC), apatite (35 wt%) and wollastonite (40 wt%) (designated A · W-GC), and apatite (20 wt%), wollastonite (55 wt%), and whitlockite (15 wt%) (designated A · W · CP-GC) were prepared. They were implanted into the tibia of mature male rabbits for 5 days, 10 days, 20 days, 30 days, 60 days, 6 months, and 12 months. All three types of glass-ceramics showed direct bonding to the bone 30 days after implantation. It was observed by SEM-EPMA 30 days after implantation that Si and Mg content decreased, P content increased, and Ca content did not change across the reactive zone from the glass-ceramics to bone. The level of P and Si in the A · W · CP-GC changed five days after implantation. In A · W-GC and A-GC, a little change in P and Si levels was observed between 10 and 20 days after implantation. The width of reactive zone was narrowest with A-GC, wider with A · W-GC, and widest with A · W · CP-GC. The dissolution of glass-ceramics stopped 6 months after implantation. This phenomenon shows that the glass-ceramics may be suitable for clinical use.

Tempered glass substrate and method of producing the same

Abstract: A tempered glass substrate of the present invention is a tempered glass substrate, which has a compression stress layer on a surface thereof, and has a glass composition comprising, in terms of mass %, 40 to 71% of SiO2, 3 to 21% of Al2O3, 0 to 3.5% of Li2O, 7 to 20% of Na2O, and 0 to 15% of K2O.