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Purpose: A portable accelerometer-based navigation system can be useful for achieving the target alignment. Tibial registration is based on the medial and lateral malleoli; however, the identification of landmarks may be difficult in obese (body mass index [BMI] >30 kg/m2) patients whose bones are not easily palpable from the body surface. This study compared tibial component alignment achieved using a portable accelerometer-based navigation system (Knee Align 2) in obese and control groups and aimed to validate the accuracy of bone cutting in obese patients. Methods: A total of 210 knees that underwent primary total knee arthoplasty (TKA) using the Knee Align 2 system were included. After 1:3 propensity score matching, there were 32 and 96 knees in the BMI >30 group (group O) and BMI ≤30 group (group C), respectively. The absolute deviations of the tibial implant from the intended alignment were evaluated in the coronal plane (hip-knee-ankle angle [HKA] and medial proximal tibial angle [MPTA]) and sagittal plane (posterior tibial slope [PTS]). The inlier rate of each cohort, which was defined as tibial component alignment within 2° of the intended alignment, was investigated. Results: In the coronal plane, the absolute deviations of the HKA and MPTA from the intended alignment were 2.2° ± 1.8° and 1.8° ± 1.5° in group C and 1.7° ± 1.5° and 1.7° ± 1.0° in group O (P=1.26, and P=0.532). In the sagittal plane, the absolute deviations of the tibial implant were 1.6° ± 1.2° in group C and 1.5° ± 1.1° in group O (P=0.570). The inlier rate was not significantly different between group C and group O (HKA: 64.6% vs 71.9%, P=0.521; MPTA: 67.7% vs 78.1%, P=0.372; PTS: 82.2% vs 77.8%, P=0.667). Conclusion: The accuracy of tibial bone cutting for the obese group was comparable to that of the control group. An accelerometer-based portable navigation system can be useful when attempting to achieve the target tibial alignment in obese patients.

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.

a Department of Orthopaedic Surgery, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan b Department of Vascular Surgery, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan c Department of Spine Surgery, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan

Tungsten powders were successfully sintered and simultaneously joined to a graphite disk using an interlayer of SiC ceramic powder, which contained Al2O3 and Y2O3 as sintering aids for the SiC. The tungsten/graphite joints were prepared at 30 MPa and temperatures ranging from 1700 °C to 2000 °C for 5 min using spark plasma sintering (SPS). The tensile strength of the joints prepared at 1700 °C reached 21 MPa. The suggested joining mechanism of the joints prepared below 1800 °C is as follows: both the sintered W metal layer and the SiC ceramic interlayer are chemically bonded together accompanying reaction phases of WC, W2C and W5Si3. A physical bond is achieved between the SiC interlayer and graphite when the SiC powder fills the open pores of the graphite and is sintered there. Although a similar joining mechanism is suggested when the joining temperature exceeds 1900 °C, the SiC interlayer disappears, and the broad reaction layer consisting of WC, W2C and trace W5Si3 is formed.

AlN ceramic-bonded carbon (AlN/CBC) was designed as a carbon-based composite with a honeycomb microstructure consisting of carbon particles and thin AlN boundary layers. In this work, four types of graphite powders were used to prepare AlN/CBC (20 vol% AlN) at 1900 °C by spark plasma sintering. The effects of hardness and size distribution of graphite particles on the formation of AlN/CBCs were investigated. Hard particles with a uniform size distribution benefit the formation of AlN/CBC, resulting in a high strength of 100 MPa and thermal conductivity of 170 W/m K. However, soft particles or hard particles with a wide size distribution will make it difficult to form the continuous AlN network, then resulting in a weak strength.

Unique porous SiC ceramics with a honeycomb structure were fabricated by a sintering-decarburization process. In this new process, first a SiC ceramic bonded carbon (SiC/CBC) is sintered in vacuum by spark plasma sintering, and then carbon particles in SiC/CBC are volatized by heating in air at 1000 °C without shrinkage. The honeycomb structure has at least two different sizes of pores; ∼20 μm in size resulting from carbon removal; and smaller open pores of 2.1 μm remaining in the sintered SiC shell. The total porosity is around 70% and the bulk density is 0.93 mg/m3. The bending and compressive strengths are 26 MPa, and 105 MPa, respectively.

AlN and graphite disks were successfully joined using a polymer plasticized ceramic tape as the interlayer by spark plasma sintering (SPS). The tape contains either composite powders of AlN and graphite or AlN powders without graphite. Both tapes contained 5 mass% Y2O3 as the sintering aid of AlN. The joining was carried out at 1700–1900 °C and 30 MPa for 5 min. No other reaction phase except for Al2Y4O9 was identified in the joints. The maximum tensile strength of the joints was obtained when the AlN–graphite composite interlayer tape was used. The joining mechanism is attributed not to the chemical bonding, but to the physical bonding of the Al2Y4O9 phase, which is solidified from the molten Al–Y–O squeezing into the porous graphite under pressure during SPS.

After placing SiC powder on an isotropic graphite substrate, the two materials were successfully joined by spark plasma sintering (SPS). The effect of an Al 2 O 3 –Y 2 O 3 sintering aid on SiC during joining was studied. The tensile strength of the joints prepared at 1800 °C under 30 MPa for 5 min reached 18 MPa. The fracture occurred not at the interface, but at the graphite substrate. The joining mechanism of SiC/graphite is attributed to the following: after the SiC powder squeezes into the open pores of graphite during sintering, the sintered SiC produces a strong bond through the interface between SiC and graphite.

Multiple epiphyseal dysplasia (MED) is a form of osteochondrodysplasia characterized by abnormal epiphyseal growth and assumed to be a clinical condition of extracellular matrix abnormality [1]. Osteoarthritis and chondral lesions, for example osteochondritis dissecans (OCD), are among the clinical expressions of MED [2, 3]. It is possible for osteoarthritic changes of the knee to develop easily even in young patients with MED [4]. Total knee arthroplasty (TKA) and correction osteotomy have been performed for severe deformity and destruction of the knee in MED patient [4, 5].

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.

The effect of Ti serving as an activator in a eutectic Ag–Cu alloy filler metal in dissimilar laser-brazed joints of isotropic graphite and a WC–Co alloy on the joint strength and the interface structure of the joint is investigated in this study. To evaluate the joint characteristics, the Ti content in the filler metal was increased from 0 to 2.8 mass%. The laser brazing was carried out by irradiating a laser beam selectively on the WC–Co alloy plate in Ar atmosphere. The threshold content of Ti required to join isotropic graphite to WC–Co alloy was 0.4 mass%. The shear strength at the brazed joint increased rapidly with increasing Ti content up to 1.7 mass%, and a higher Ti content was found to be likely to saturate the shear strength to a constant value of about 14 MPa. The isotropic graphite blocks also fractured at this content. The concentration of Ti observed at the interface between isotropic graphite and the filler metal indicates the formation of an intermetallic layer of TiC.

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).

A new carbon composite called ceramic bonded carbon (CBC) is composed of separated carbon particles bonded with thin ceramic boundaries. To fabricate reliable plasma facing components, AlN ceramic bonded carbon (AlN/CBC, 20 vol.% AlN) was directly cladded with tungsten (W) at 1700 °C by spark plasma sintering. The cladding shows strong bonding, which is attributed to the formation of interface layer containing mixed WC/W 2 C and AlN ceramic. The interface between W and AlN/CBC was analyzed and the cladding mechanism was discussed.

To obtain light and tough materials with high thermal conductivity, AlN ceramic bonded carbon (AlN/CBC) composites were fabricated at temperatures from 1600 to 1900 °C in a short period of 5 min by the spark plasma sintering technique. All AlN/CBCs (20 vol% AlN) have unique microstructures containing carbon particles of 15 μm in average size and continuous AlN boundary layers of 0.5–3 μm in thickness. With an increase in sintering temperature, AlN grains grow and anchor into carbon particles, resulting in the formation of a tight bonding layer. The AlN/CBC sintered at 1900 °C exhibited a light weight (2.34 g/cm3), high bending strength (100 MPa), and high thermal conductivity (170 W/mK).

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.

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

To obtain light, strong materials with high thermal conductivity, a new carbon-based material, AlN ceramic bonded carbon (AlN/CBC), was fabricated by combining gelcasting and spark plasma sintering techniques. The results showed that AlN/CBC (20 vol% AlN) has a unique microstructure containing carbon grains of 15 μm in size and an AlN grain-boundary layer of 0.5–3 μm in thickness. Continuous AlN ceramic networks bonded the carbon grains together. Compared with the conventional AlN/carbon (AlN/C) material made by a ball-milling method, AlN/CBC showed a higher strength and a higher thermal conductivity by two and four times, respectively.

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.

Single-phase β-sialon powders (z = 2–4) have been prepared with homogeneous compositions by the combustion synthesis. The raw materials (Si, Al and SiO2) were combusted under N2 pressure of 1 MPa. Without using a diluent, the reaction temperatures were very high (>2000 °C) and the combustion products contained Si and Al residues. With addition of commercial β-sialon (z = 1) as a diluent (up to 50 wt%), both the reaction temperatures and amount of residual Si and Al significantly decreased. The combustion reactions completed at 50 wt% dilution, and pure β-sialon phases were synthesized. When the combustion product itself is used instead of the commercial diluent, the phase content of desired z value increased with the repetition times until a single-phase powder is produced. The sinterability of the synthesized powders was then tested using 5 wt% Y2O3 as a sintering aid by the spark plasma sintering (SPS).

The authors have studied a new method of intermetallic coating using a small TIG welder. This method is based on a reaction between small liquid beads produced from very thin metal wire and the substrate metal surface. The authors designed a computer-aided 3-dimensional micro welder (3DMW) for a previous study on freeform fabrication of intermetallics, and have applied it to this study on intermetallic coating. In this study, a predetermined length of thin aluminum wire was fed onto the titanium substrate surface, and a spark was stricken from a thin electrode of a W-Ce2O3 alloy to make a small aluminum liquid bead on the titanium substrate surface and to simultaneously melt a small area of the substrate surface beneath the liquid bead. All process conditions had been programmed beforehand, including the length of the wire feeding per spark, the position of the electrode, electric power, movement of the stage holding the substrate, etc. The liquid bead containing aluminum and titanium rapidly solidified on the titanium substrate surface producing titanium aluminides on it. Repetition of the aluminum wire feeding, the electrode positioning and the spark striking produced a coating layer consisting of sub-layers of TiAl3, TiAl and Ti3Al from the surface side to the substrate side. Vickers hardness and wear resistance of the coated sample were remarkably improved.

Uniform quasi-aligned AlN nanowhiskers grown in the reacting Al particles have been successfully prepared in high content by combustion synthesis using NH4Cl as a morphology-controlled promoting additive. FE-SEM and TEM images show that the nanowhiskers, which are singlecrystalline hexagonal wurtzite AlN growing along [0 0 1] direction, have diameters in the range of 80–170 nm and a length of several to several tens of micrometers. The effect of NH4Cl on the growth of nanowhiskers was discussed. It was found that NH4Cl not only controlled the products’ morphology, but also changed the combustion behavior and nitridation mechanism in the combustion synthesis process. # 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Quasi-aligned AlN nanowhiskers were formed by combustion synthesis (CS) at a low nitrogen gas pressure of 0.25 MPa. The starting charge consists of Al and AlN diluent (40/60 mol%) with a mixture of CaO and NH 4 Cl additives (5 wt.% each). The CS proceeded in a mild way with the combustion temperature of 1530 °C and the combustion speed of 0.24 mm/s. The uniform quasi-aligned nanowhiskers were formed inside the reacting Al particles covered with a thin crust. In addition, the nanowhiskers, which are single-crystalline hexagonal wurtzite structure growing along [0 0 1] direction, have the diameters in the range of 60–150 nm and a length of several to several tens of micrometers. A quenching technique was used to investigate the phase transformation and morphologies evolution during the CS of AlN nanowhiskers. In addition, the possible intermediate reactions during the CS process were confirmed by thermodynamic analysis. The results indicated that the formation of quasi-aligned AlN nanowhiskers involves the dissociation of NH 4 Cl, formation of micro-reactors (Al/C 12 A 7 sintered AlN core–crust spheres), nucleation and growth of one-dimensional nanowhiskers in the micro-reactors mostly by VS mechanism.

3D Micro welding (3DMW) is a newly developed rapid prototyping method for metals. It is a combination of micro tungsten inert gas (micro-TIG) welding and a layered manufacturing method. The tip of a thin metal wire is melted by a micro-TIG welder to form a small metal bead. By building up metal beads layer by layer under computer control, a 3D metal object is eventually formed. The fabrication of simple 3D objects made of Inconel alloy 600 was studied. The interface between adjacent beads had good adhesion. No cracks or pores remained in the formed objects. The tensile strength, elongation, density, and Vickers hardness were measured and compared to those of the commercial superalloy. The obtained results suggest that actual micro components or tools of refractory metals with high strength and oxidization resistance can be formed without molds by 3DMW.

3D micro-welding (3DMW) is a newly developed rapid prototyping method for metals. It combines a micro-tungsten inert gas (TIG) welding with a layered manufacturing method. A tip of a thin metal wire is melted by a micro-TIG welder to form a small metal bead. By building up metal beads layer by layer under computer control, a 3D metal object is eventually formed. A wide variety of metals and alloys can be used. The Ti–Al based intermetallic alloys have superior mechanical and chemical properties. However, the forming process is difficult and costly. We have tried to fabricate 3D objects of the Ti–Al alloy system by using several thin Ti and Al wires. Some simple objects with a unique microstructure or graded composition are demonstrated.

Feasibility of anew method of titanium aluminide coating on titanium surface based on a reaction between aluminum liquid beads and the surface of titanium substrate has been studied using a computer-aided three-dimensional microwelder (3DMW) designed by the present authors. A predetermined length of thin aluminum wire was fed onto the substrate Surface, and a spark was stricken from a thin electrode of a W-Ce2O3 alloy to make a small aluminum liquid bead on the substrate Surface and to simultaneously melt a small area of the substrate surface beneath the bead. All conditions including the length of the wire feeding, the position of the electrode, electric power, etc. had been programmed beforehand. The liquid bead containing aluminum and titanium rapidly solidified on the titanium substrate surface producing titanium aluminides on it. Repetition of the aluminum wire feeding, the electrode positioning and the spark striking produced a coating layer consisting of sub-layers of TiAl3, TiAl and Ti3Al from the surface side to the substrate side. Vickers hardness and wear resistance of the coated sample were remarkably improved. (C) 2008 Elsevier B.V. All rights reserved.

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.

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.

Dense three-dimensional microphotonic crystals of SiO 2 -Al 2 O 3 ceramics were fabricated using microstereolithography and successive sintering process. The forming dimensional tolerance for a 50vol% ceramic paste is 10μm 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.

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.

Fabrication and terahertz wave properties of alumina microphotonic crystals with a diamond structure were investigated. The three-dimensional diamond structure was designed on a computer using 3D-CAD software. The designed lattice constant was 500 μm. The structure consisted of 8 × 8 × 4 unit cells. Acrylic diamond structures with an alumina dispersion of 40 vol% were formed by using microstereolithography. Fabricated precursors were dewaxed at 600 °C and sintered at 1500 °C. The linear shrinkage ratio was about 25%. The relative density reached 97.5%. The electromagnetic wave properties were measured by terahertz time-domain spectroscopy. A complete photonic band gap was observed at the frequency range from 0.40 THz to 0.47 THz, and showed good agreement with the simulation results calculated by the plane wave expansion method. Moreover, localized modes were obtained at the frequencies 0.42 THz and 0.46 THz by introducing an air defect in the diamond structure. They corresponded to the simulation by the transmission line modeling method.

Osteoarthritis (OA) is the most common form of arthritis and is characterized by the gradual loss of articular cartilage. Several OA-susceptibility genes have been identified; however, there are few pharmaceutical targets that can be targeted with small-molecule compounds. To investigate whether a susceptibility gene for OA exists among G-protein-coupled receptors (GPCRs), we performed a stepwise association study for 167 single nucleotide polymorphisms (SNPs) in 44 GPCR genes that were present in cartilage. Through the stepwise association study, an SNP located in the promoter region of EDG2 [endothelial differentiation, lysophosphatidic acid (LPA) GPCR, 2] (-2,820G/A; rs10980705) showed significant association with knee OA in two independent populations (pooled P = 2.6 x 10(-5)). Luciferase and electrophoretic mobility shift assays indicate that this SNP exerts an allelic difference on transcriptional activity and DNA binding in synovial cells, with the susceptibility allele showing increased activity and binding. EDG2 encodes an LPA receptor dominantly expressed in the synovium. The LPA receptor increased the expression of inflammatory cytokines and matrix metalloproteases in synovial cells. Our findings suggest that the LPA-EDG2 signal is involved in the pathogenesis of OA via catabolic process.

Carbon-matrix composites with self-assembly interconnected carbon nano-ribbon networks were fabricated using natural and inexpensive rice husks by impregnating the rice husks with transitional metal solutions and sintering. The nano-structure of the composite was characterized using transmission electron microscopy. The electromagnetic interference shielding effectiveness of the composite was evaluated in the frequency range of 30 kHz–1.5 GHz. The electrical conductivity was measured as a function of the sintering temperature. These characteristics were compared with those of carbon-matrix composites without nano-ribbon networks.

Manganese doping of gallium oxynitride was investigated to obtain a magnetic semiconductor by nitriding a precursor in ammonia flow. The precursor was obtained by prefiring a mixed gel made of Mn 2+ and Ga 3+ nitrates and citric acid in aqueous solution. The products were isostructural with hexagonal GaN. The doping limit was 10 and 5 at% in the samples nitrided at 750 and 850 °C, respectively. Chemical analysis of the products suggested that they were manganese doped gallium oxynitrides. Oxide and nitride ions were randomly distributed in the anion sites in the latter product. Manganese oxide cluster might be formed in the former. The product nitrided at 850 °C showed an antiferromagnetic interaction with a Weiss temperature θ = −38 K, while the product nitrided at 750 °C was paramagnetic.

Single-phase (β-SiAlON (Si4Al2O2N6, z = 2) powder has been prepared by the combustion synthesis method. The raw materials (Si, Al and SiO2) were combusted with different ratios of (β-SiAlON (z = 1) diluent (0, 10, 20, 30, 40, 50wt%) in 1MPa of N2 pressure. Without diluent, the reaction temperature was very high (> 2000°C) and the product contained metal Si residue besides (β-SiAlON product. Both the reaction temperature and amount of residual Si decreased gradually with the increase of diluent content up to 50wt%. At 50wt% dilution, the combustion temperature was 1859°C and the XRD analysis showed complete conversion to pure (β-SiAlON (z = 2). The individual peaks of (β-SiAlON (z = 1) diluent were also detected in the XRD patterns and disappeared after using the product itself as a diluent five time repeats of combustion at which single-phase (β-SiAlON (z = 2) was produced. The sinterability of the best synthesized powder was further studied by spark plasma sintering (SPS) with 5wt% Y2O3 as a sintering aid. High densification (∼97.3%) was obtained after sintering at 1600°C for 5 min under 30MPa pressure with heating and cooling rates of 100°C/min. The Vickers hardness and fracture toughness of the sintered SiAlON were 14.8GPa and 4.4MPam1/2, respectively.

Rod-like aluminum nitride (AlN) nanoparticles were prepared by the nitriding combustion synthesis method. A charge composed of Al and AlN diluent powders (40/60 mol%) with 5 mass% MgO as additive was combusted under 1 MPa nitrogen atmosphere. The combustion temperature of the reaction was 2030°C and the speed was 1.58 mm/s. The FE-SEM observation showed that the rod-like AlN nanoparticles have diameters in the range of 90-300 nm and maximum length about 2 μm. It also showed evidences of the core-shell model of nitridation where the nanorods grew near the flow-out of eggshell-type AlN hollows. The EDX analyses showed the formation of Mg-Al-O-N droplets on the tips of AlN nanorods which strongly suggested that the vapor-liquid-solid (VLS) mechanism was the predominant growth mode. However, when the liquid droplets necessary for VLS were exhausted with continuous covering on the surface of the growing nanorods, the growth mode changed probably to vapor-solid (VS) mechanism. Furthermore, a growth model of the formation of rod-like AlN nanoparticles was proposed and discussed in accordance with experimental results.

A new titanium aluminide coating method on titanium surface has been proposed, which is characterized by arc surface melting of an aluminum plated titanium surface. The arc surface melting was performed using a computer aided 3-dimensional micro welder (3DMW) designed by the present authors. The arc heat melted the aluminum plated titanium surface and produced a titanium aluminide layer of a ~300 μm thickness on the surface of titanium substrate. The titanium aluminide coated sample exhibited 500–700 in Vickers hardness number and excellent wear resistance.

Three-dimensional (3D) photonic crystals with a diamond structure composed of TiO2 ceramic spheres in a resin matrix were fabricated by stereolithography. The lattice constant was 12 mm. The diameter of the spheres was about 5 mm. These photonic crystals composed of ceramic spheres showed four complete photonic band gaps at around 5.7 GHz between the 2nd and 3rd bands, 7.8 GHz between the 8th and 9th bands, 10.4 GHz between the 24th and 25th bands, and 13.1 GHz between the 54th and 55th bands. The propagation characteristics of microwaves propagating through the photonic crystals agreed well with the calculated results using the plane-wave expansion method.

A newly developed freeform fabrication process named 3D Micro-Welding, which is a combined system of a micro-TIG welding and a layered manufacturing method, is demonstrated. Various refractory alloys such as Inconel, stainless steel, and Invar can be freeformed besides elemental metals like titanium. Small metal beads of ~1mm in diameter are formed by emitting micro arc to the top of a thin metal wire of 0.2mm diameter. A fused bead is welded to a metal substrate or previously formed beads. By continuing this process and building up beads layer by layer under the control of CAD/CAM system, 3D objects were produced. In this study, optimization of micro-welding parameters such as the waveform of pulsed arc current and electrode materials were investigated and simple 3D objects of Inconel 600, SUS 304, Invar 42 were formed. The interfaces between adjacent beads were joined well and no crack or pore existed in the formed objects. The density and Vickers hardness of Inconel 600 objects showed comparable values to the commercial Inconel alloy, however the yield strength and Young’s modulus was about 80% and 70% of that alloy, respectively.

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.