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This paper uses two versions of a vertical product differentiation model with price competition to investigate how strategic behavior between rival firms influences which organizational production mode each firm adopts: that is, either vertical integration or outsourcing. We show that not only a symmetric configuration, where both high‐ and low‐quality firms outsource, but also an asymmetric configuration, where the high‐quality firm produces in‐house whereas the low‐quality firm outsources, are acceptable as a subgame‐perfect equilibrium outcome. We explore the implications of these results in light of the recent slump in business of Japanese electronics enterprises in the flat‐panel television industry. [ABSTRACT FROM AUTHOR]

A dense SiC coating on carbon particles has been developed using SiO powders as the Si source and a chemical vapor reaction method. The coating process was controlled by atmosphere, coating temperature, time, and weight ratio of SiO/C. The SiC-coated carbon particles, with a mean particle size of 20 μm, were sintered at 2000°C under 40 MPa for 20 min by spark plasma sintering ( SPS). The product, called ceramic bonded carbon ( CBC), had a unique microstructure, with a 3D micro-network structure consisting of carbon particles covered with 1~5 μm thick SiC boundary layers. The sintering behavior of SiC/ CBCs was analyzed in terms of the network formation of SiC boundary layers at over 1800°C and the grain growth of SiC at 2000°C. SiC/ CBCs showed a bending strength of 150 MPa and a low shore hardness of 40. These materials could also be easily joined to SiC ceramics using SPS. [ABSTRACT FROM AUTHOR]

Ceramic bonded carbon ( CBC) is a new composite consisting of carbon particles bonded with thin ceramic boundaries. It can not only reinforce carbon but also provide joining capability with other materials. To obtain light-weight heat dissipating substrates with matched low coefficients of thermal expansion, a top layer of AlN and a bottom layer of AlN/ CBC (20 vol% AlN) were sintered and joined in one step by hot-pressing at 1950°C. Both AlN and AlN/ CBC were densified and bonded tightly. AlN/ CBC has a density of 2.30 g/cm3, bending strength of 112 MPa, and thermal conductivity of 170 W/mK. The obtained AlN-AlN/ CBC plates showed a high strength as a result of the direct AlN-AlN sintering at the AlN and AlN/ CBC interface. [ABSTRACT FROM AUTHOR]

New composites called ceramic-bonded carbon ( CBCs), consisting of a three-dimensional structure of carbon particles bonded with thin ceramic boundaries, were developed. To fabricate light and tough CBCs and to understand their reinforcing mechanism, Si3N4 and carbon powders (25:75 in volume ratio) were gelcasted and then sintered by spark plasma sintering at temperatures of 1700-1900°C. The ceramic boundary of SiC was formed in situ at above 1700°C by the reaction of Si3N4 and C. The sintered CBCs showed a unique microstructure consisting of carbon particles and ceramic boundaries of 15 μm in size and 0.5-3 μm in thickness, respectively. With an increase in sintering temperature, physical bonding of ceramic grains to the carbon particles was enhanced as the grain growth of SiC increased. The SiC/ CBCs sintered at 1900°C were highly dense (97% theoretical density), lightweight (2.36 mg/m3), and had both relatively high bending strength and thermal conductivity (135 MPa and 140 W/mK, respectively). [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is the most common joint disorder in humans. Most of the animal models of OA were developed by surgical destabilization of joints or through transgenic approaches, and information from naturally occurring models of OA is very limited. The mouse strain STR/ort is recognized as a spontaneous model of OA. This mouse is unique in that it develops late onset cartilage degeneration of the tibio-femoral joint, similar to human OA. The purpose of this study was to identify quantitative trait loci (QTL) for the OA phenotype in STR/ort. Whereas the trait had been reported to be recessive, a significant population of the F1 generation exhibited OA phenotype. Thus, backcrossed (BC) mice generated by crossing F1 male to C57BL/6N female mice were used for genetic analysis. Degeneration of articular cartilage in BC mice was evaluated by scanning electron microscopy. Linkage analysis was carried out using microsatellite markers covering the entire genome. Cartilage degeneration in STR/ort mice was a polygenic trait. A QTL for the OA phenotype was mapped to a region 20 centimorgans proximal to the centromere of chromosome 4 (LOD = 3.37, p = 0.0065). A QTL associated with the onset of cartilage degeneration in C57BL/6N mice was also identified on chromosome 5 (LOD = 3.04, p = 0.0147). These results suggest that multiple loci are involved in the OA phenotype in mice. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:15-20, 2012 [ABSTRACT FROM AUTHOR]

Objective When cultured in monolayers, articular chondrocytes undergo an obvious phenotypic change. Although the involvement of integrins has been suggested, the exact mechanisms of the change have not been determined. This study was undertaken to clarify the mechanisms underlying the loss of chondrocyte phenotype early after plating. Methods Primary cultured human articular chondrocytes were used for the experiments. Involvement of respective integrins in the phenotypic change was investigated in RNA interference (RNAi) experiments. A signaling pathway involved in the change was identified in experiments using specific inhibitors and adenoviruses encoding mutated genes involved in the pathway. Adenoviruses carrying mutated GTPases were used to determine the involvement of small GTPases in the process. Results In monolayer-cultured chondrocytes, suppression of αv or β5 integrin expression by RNAi inhibited morphologic changes in the cells and increased (or prevented a reduction in) the expression of various cartilage matrix genes. Consistent results were obtained in experiments using a blocking antibody and a synthetic inhibitor of αvβ5 integrin. The decrease in cartilage matrix gene expression in chondrocytes after plating was mediated by ERK signaling, which was promoted primarily by αvβ5 integrin. In articular chondrocytes, the affinity of αvβ5 integrin for ligands was regulated by the small GTPase R-Ras. R-Ras was gradually activated in monolayer-cultured chondrocytes after plating, which caused a gradual decline in cartilage matrix gene expression through enhanced αvβ5 integrin activation and the subsequent increase in ERK signaling. Conclusion Our findings indicate that αvβ5 integrin may be involved in the change that occurs in monolayer-cultured chondrocytes after plating. [ABSTRACT FROM AUTHOR]

Developing a Cournot two-stage game model with strategic capital interaction, we compare two different kinds of equilibrium in a labour-managed (LM) duopoly. An LM firm's reaction function is negatively sloped when capital and output are simultaneously determined, while the slope of its reaction function in the second stage changes in sign depending on the magnitude of its labour-expansion elasticity. Hence, whether the LM firms employ more capital and produce greater output at the equilibria in the two-stage game model than at the equilibria resulting from the simultaneous selection of capital and output depends on the magnitude of their labour-expansion elasticity. [ABSTRACT FROM AUTHOR]

The article discusses a study which determined the chondrocyte metabolism in osteoarthritic cartilage. The cartilage was divided into three zones and gene expression profiles were determined by custom-designed microarray focused on chondrocyte-related genes. The metabolic activity of chondrocytes differed among zones.

The article discusses a study which described a technique that may be used in the freeform fabrication of alumina dental-crown models through stereolithography. Due to their desirable aesthetics and biocompatibility, ceramic materials have been popular in the area of dental restoration for dentures and crowns. Glass infiltration has been used to improve the flexural strength of sintered specimens used in the study.

Dense three-dimensional (3D) microdevices of ZrO2-toughened Al2O3 (ZTA) were fabricated using microstereolithography and a subsequent sintering process. Using microstereolithography, 3D green bodies could be formed from a 40 vol% ZTA ceramic–resin paste. After sintering, the fabricated 3D devices are converted into dense ceramic devices without deformation. In this study, a gear (with a tooth edge of 25 μm) and a photonic crystal (with a lattice constant of 500 μm) were designed and fabricated. The dimensional accuracy of the fabrication process is within 20 μm and the sintering shrinkage is around 26% for these microdevices. The relative density of the sintered ZTA ceramics reached 96.5% of theoretical value. The measured hardness and toughness were about 14 GPa and 11 MPa m1/2, respectively, in both the top and side surfaces. A band gap between 320 and 420 GHz was observed in the ZTA photonic crystal. The microstereolithography process can be easily applied to other ceramic materials and devices. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) photonic crystals composed of a center polycrystalline yttrium iron garnet (YIG) plate sandwiched with alternate alumina and resin plates were fabricated using stereolithography. The formed crystals showed a transmission mode of microwave in band gap as a result of resonance at the YIG plate. The transmission frequency and intensity were controlled by applying an external magnetic field. These phenomena can be explained by Faraday and Voigt effects of YIG in magnetic field. The propagation characteristics of microwaves agreed well with the calculated results using the finite element method. [ABSTRACT FROM AUTHOR]

Dense three-dimensional microphotonic crystals of SiO2–Al2O3 ceramics were fabricated using microstereolithography and successive sintering process. The forming dimensional tolerance for a 50 vol% ceramic paste is 10 μm and sintering shrinkage is around 12%. Diamond-type photonic crystals with lattice constants of 500 and 125 μm were formed and sintered successfully. The band gaps of the samples were measured and compared with the theoretically calculated band diagram. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) metallodielectric photonic crystals with a diamond structure were fabricated in order to investigate the formation of stop bands and the absorption ability for microwaves with the dielectric absorbing media embedded into the 3D metal lattice. First, the metallic photonic crystals were prepared by filling the epoxy molds formed by stereolithography with a metal alloy having a low melting point of 70°C, followed by removal of the molds. The metallodielectric photonic crystals were then fabricated by infiltrating the porous metal crystal with a SiC/polyester mixture. The lattice constant of photonic crystals was 15 mm. The effects of different aspect ratios of diamond lattice rods, number of metallic lattice units along Γ-L 〈1 1 1〉, Γ-X 〈1 0 0〉, and Γ-K 〈1 1 0〉 directions, and metallodielectric samples along the Γ-X 〈1 0 0〉 direction on the formation of stop band and microwave absorption ability were investigated in the frequency range from 3 to 30 GHz. Metallodielectric photonic crystals formed showed good absorption ability. The measured transmission spectra of the metallic and metallodielectric crystals agreed well with the simulation of the transmission line modeling method. [ABSTRACT FROM AUTHOR]

Quasi-aligned AlN nanofibers were formed by the nitriding combustion synthesis according to a unique micro-reactor model. A charge composed of aluminum and aluminum nitride diluent powders (40/60 mol%) with a mixture of yttria and ammonium chloride as additives (5 wt% each) was combusted at low nitrogen gas pressures of 0.25 MPa. The FE-SEM images of as-synthesized AlN product showed the formation of ball-like grains (same shape and size as the original Al reactant) that consisted of a thin surface nitride layer or crust cover quasi-aligned AlN nanofibers grown in the interior. The cross-sectional view is sea anemone like. Formation of this novel morphology is believed to occur through a two-stage process. The first one occurs at the preliminary stage of the combustion outside Al particles. After the ignition, the heat generated causes the sublimation and dissociation of ammonium chloride into various gaseous species. This effectively interrupts the combustion and slows down the increase of reaction temperature. In addition, yttria interacts with the native oxide layer present on the surface of Al particles and forms a stable Al–N–Y–O crust. The second stage begins by the infiltration of various gaseous species such as HCl(g), NH3(g), and N2(g) through the crust into the molten Al cores. The “crust–core” systems function as “micro-reactors” where both the nitridation and growth processes occur inside. The molten Al cores are spontaneously halogenated to AlCl3 vapors and the nitridation proceeds by the gas–gas reaction of AlCl3 and NH3/N2 vapors. The AlN nanofibers are then grown from the vapor phase quasi-aligned inside the micro-reactors by VLS and VS mechanisms. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) photonic crystals with a diamond structure made of a dense SiO2 ceramic were successfully fabricated using a CAD/CAM micro-stereolithography and sintering process. The designed lattice constant of the diamond unit cell was 500 μm and the forming tolerance from 50 vol% SiO2 paste (before sintering) was around 15 μm. After the SiO2-resin photonic crystals were formed via micro-stereolithography, they were converted to pure SiO2 ceramic photonic crystals of 99% theoretical density by sintering at 1400°C. The electromagnetic wave propagation in these dense SiO2 photonic crystals was measured by terahertz-time-domain spectroscopy. The results showed that the band gap appeared between 470 and 580 GHz in the Γ– X〈100〉 direction, between 490 and 630 GHz in the Γ– K〈110〉 direction, and between 400 and 510 GHz in the Γ– L〈111〉 direction, resulting in the formation of a common band gap in all directions between 490 and 510 GHz. These results agreed well with the band gaps calculated by the plane wave expansion method. [ABSTRACT FROM AUTHOR]

Three-dimensional photonic crystals with a diamond structure composed of YSZ (3 mol% Y2O3-stabilized ZrO2) spheres in a resin matrix were fabricated by using stereolithography. The lattice constant was 12 mm and the diameter of the spheres was 5 mm. These photonic crystals made of ceramic spheres showed complete photonic band gaps at around 12 GHz between the eighth and ninth bands. The propagation characteristics of microwaves agreed well with the calculated results using the plane wave expansion method. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) photonic crystals with a diamond structure made from 40 vol% TiO2–acrylate dielectric composites were formed by means of a CAD/CAM micro-stereolithography system. The lattice constant of the diamond unit cell was 500 μm and the forming accuracy was 10 μm. The photonic band gap in the Γ–X 〈100〉 direction measured by terahertz-time-domain spectroscopy appeared at 280–360 GHz, which agreed fairly well with the band gap calculated by the plane wave expansion method. [ABSTRACT FROM AUTHOR]

Three-dimensional photonic crystals were fabricated by infiltrating an epoxy mold with a SiC/polyester mixture. The epoxy molds with normal or inverse diamond structures were formed by stereolithography. The size of the mold was 45 mm × 18 mm × 18mm, and the lattice constant of the photonic crystals was 18 mm. The effects of the epoxy mold type, aspect ratio (the ratio of height and diameter of a diamond lattice rod), and number of sample units on the formation of photonic band gap (PBG) and microwave absorption ability along the 〈100〉 direction were studied. The attenuations of microwave transmission and reflection were measured through the photonic crystal samples at a frequency range of 3–12 GHz with a network analyzer. The results obtained suggest that the combination of the absorbing material SiC and diamond structure has a dual effect to form a PBG with a high absorption ability. [ABSTRACT FROM AUTHOR]

Three-dimensional photonic crystals with a diamond lattice structure consisting of 5 × 5 × 5 unit cells with the unit cell dimension of 15 mm were fabricated using TiO2-based ceramic particles dispersed epoxy by stereolithography. The diamond lattice showed a perfect band gap between 14.3 and 15.8 GHz. An air cavity defect with a rectangular shape (15 mm × 45 mm × 15 mm) was introduced at the center of the crystal by extracting 3 unit cells in order to investigate the shape effect of the defect on the formation of localized defect modes of electromagnetic wave. When microwaves were radiated normal to the wide sides (45 mm × 15 mm) of the rectangular shape defect, a sharp localized mode appeared at the middle of the band gap. However, no localized mode was observed for incident waves normal to the smaller side (15 mm × 15 mm) because of the symmetry mismatching between internal eigenmodes in the defect cavity and incident plane waves. The mode analysis using a simple cavity model showed the penetration of the electric field of resonant modes about 2.4 mm into the host lattice. [ABSTRACT FROM AUTHOR]

Ceramic photonic crystals with diamond structure were fabricated using stereolithography and successive sintering. The green body of an epoxy resin incorporating 10 vol% TiO2–SiO2 was formed by stereolithography and then heated in air at 1100°–1400°C for 2 h. The sintered products maintained the diamond structure with a linear shrinkage ratio of about 57% and a porosity of 38%. The ceramic photonic crystal with eight unit cells showed a photonic band gap at the center frequency of 23.5 GHz. This fabrication method of three-dimensional (3D) ceramic photonic crystals is applicable to other 3D structural ceramics and does not require any molding techniques. [ABSTRACT FROM AUTHOR]

Diamond particles were coated with a thin SiC layer by the reaction of SiO vapor with diamond, and the growth mechanism of SiC as well as the oxidation resistance of the SiC coated diamond were studied. The growth process of the SiC layer can be separated into two steps. In the first step, a thin layer of SiC with a thickness of about 15 nm is formed due to the reaction between SiO vapor and diamond. In the second step, nanometer-sized SiC granules are deposited on the SiC layer by the reaction between SiO vapor and CO. The apparent activation energy for the formation of SiC layer on diamond was found to be 100 k J/mol. This value suggests that the SiC coating process occurred mainly by vapor-phase reaction. The oxidation resistance of the SiC-coated diamond was improved depending on the thickness of the SiC layer. Oxidation of the SiC-coated diamond particles began at 950°C, which was 400°C higher than that of uncoated diamond. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes (MWCNTs) were coated with a SiC layer using SiO vapor. The growth mechanism of SiC and the oxidation resistance of the SiC-coated MWCNTs were studied. The growth of the SiC layer was controlled by adjusting the partial pressure of CO2 using carbon felt placed in a crucible. The nanometer-sized SiC particles were deposited onto the tubes by the reaction between SiO(g) and CO(g). On the other hand, the thin surface of the MWCNTs was converted to the SiC layer when the carbon felt was not used. The oxidation durability of MWCNTs was improved by the SiC coating. MWCNTs were oxidized completely in air at 650°C for 60 min. However, about 90 mass% of the SiC-coated MWCNTs remained after the same oxidation test. [ABSTRACT FROM AUTHOR]

A new concept of smart processing is proposed that can produce advanced materials and components by finely controlling processing energy and engineering structures. New functional components of 3D photonic crystals and fractals are demonstrated, which are constructed of dielectric ceramics and a polymer using a CAD/CAM stereolithography system. By modifying the structure of diamond-like photonic crystals using free-form fabrication, electromagnetic waves can be controlled, opening the way for new applications in communication and sensing technology. The photonic fractal, a new material that can strongly localize electromagnetic waves without reflection and transmission, will also lead to new applications in the energy and medical fields. [ABSTRACT FROM AUTHOR]

Photonic crystals with a diamond structure of epoxy lattices in which TiO[sub 2]-based ceramic particles are dispersed were fabricated by stereolithography. The periodicity of the lattice was designed to reflect electromagnetic waves in the gigahertz range. The volume fraction (β) of the dielectric lattice medium was modified from 14% to 33% by changing the rod diameter of the lattice. The photonic band gap was observed along Γ-L 〈111〉, Γ-X 〈100〉, and Γ-K 〈110〉 directions and the complete photonic band gap was formed at over β = 20%. The width of the forbidden gap increased gradually when the β increased over 14%, and reached 2.4 GHz at β = 33%. These results agreed with the band calculation using the plane wave expansion method. [ABSTRACT FROM AUTHOR]

A simple process for depositing a coating of silicon carbide (SiC) crystallites ∼10 nm in size onto diamond particles has been developed. SiO powders react with diamond in a vacuum at 1350°C to form a uniform β-SiC polycrystalline layer ∼60 nm thick. The SiC coating improves the oxidation resistance of the diamond. A cemented carbide material containing 20vol%-SiC-coated diamond particles was sintered to a relative density of 99.5% by pulsed-electric-current sintering. A Vickers hardness and indentation fracture toughness of 15 GPa and 16.3 MPa·m[sup ½] respectively, were obtained. This toughness is two times higher than that of cemented carbide containing no particles. The higher toughness is attributed to deflection and blockage of crack propagation by the diamond particles. [ABSTRACT FROM AUTHOR]

Fabricates the three-dimensional photonic crystals with periodic variations in the dielectric constant using stereolithographic rapid prototyping method. Formation of photonic band gaps in a gigahertz range; Attenuation of transmission amplitude; Composition of structures of millimeter-scale ordered epoxy lattices.

New composites called ceramic‐bonded carbon (CBCs), consisting of a three‐dimensional structure of carbon particles bonded with thin ceramic boundaries, were developed. To fabricate light and tough CBCs and to understand their reinforcing mechanism, Si3N4 and carbon powders (25:75 in volume ratio) were gelcasted and then sintered by spark plasma sintering at temperatures of 1700–1900°C. The ceramic boundary of SiC was formed in situ at above 1700°C by the reaction of Si3N4 and C. The sintered CBCs showed a unique microstructure consisting of carbon particles and ceramic boundaries of 15 μm in size and 0.5–3 μm in thickness, respectively. With an increase in sintering temperature, physical bonding of ceramic grains to the carbon particles was enhanced as the grain growth of SiC increased. The SiC/CBCs sintered at 1900°C were highly dense (97% theoretical density), lightweight (2.36 mg/m3), and had both relatively high bending strength and thermal conductivity (135 MPa and 140 W/mK, respectively). [ABSTRACT FROM AUTHOR]

A dense SiC coating on carbon particles has been developed using SiO powders as the Si source and a chemical vapor reaction method. The coating process was controlled by atmosphere, coating temperature, time, and weight ratio of SiO/C. The SiC‐coated carbon particles, with a mean particle size of 20 μm, were sintered at 2000°C under 40 MPa for 20 min by spark plasma sintering (SPS). The product, called ceramic bonded carbon (CBC), had a unique microstructure, with a 3D micro‐network structure consisting of carbon particles covered with 1~5 μm thick SiC boundary layers. The sintering behavior of SiC/CBCs was analyzed in terms of the network formation of SiC boundary layers at over 1800°C and the grain growth of SiC at 2000°C. SiC/CBCs showed a bending strength of 150 MPa and a low shore hardness of 40. These materials could also be easily joined to SiC ceramics using SPS. [ABSTRACT FROM AUTHOR]

Diastrophic dysplasia sulfate transporter (DTDST) is a sulfate transporter required for the synthesis of sulfated proteoglycans in the cartilage. Over 30 mutations have been described in the DTDST gene, which result in a continuous clinical spectrum of recessively inherited chondrodysplasias, including, in order of increasing severity, a recessive form of multiple epiphyseal dysplasia (rMED), diastrophic dysplasia (DTD), atelosteogenesis type II (AO-II) and achondrogenesis 1B (ACG-1B). Correlation between disease severity and residual sulfate transport activity has been reported. Here we report a patient with DTDST mutations, whose manifestations fell in a range between AO-II and DTD. The patient was a compound heterozygote for the recurrent c.835C>T (p.R279W) and novel c.1987G>A (p.G663R) mutations. Immunocytochemical analysis in HEK293 cells showed that the p.G663R mutation was localized within the cytoplasm, and not to the cell membrane, suggesting p.G663R is a loss-of-function mutation. Our case supports the previously described correlation between the severity of the phenotype and the putative level of residual transport function., (Copyright 2006 Wiley-Liss, Inc.)