Deposition of Hard Chrome Coating onto Heat Susceptible Substrates by Low Power Microwave Plasma Spray

Microwave plasma spray requires relatively low power, which is lower than 1 kW in comparison to other plasma spraying method. Until now, we are able to deposit Cu and Hydroxyapatite coating onto heat susceptible substrate, CFRP which are difficult for conventional plasma spray due to the excessive heat input. In this paper, a hard chromium coating was deposited onto SUS304 and CFRP by a low power microwave plasma spray technique. By controlling the working gas flow rate and spraying distance, a hard chrome coating with thickness of approximately 30 μm was successfully deposited onto CFRP substrate with hardness of 1110 Hv0.05. Furthermore, the coating produced here is higher than that produced by hard chrome plating

An efficient synthesis of cycloalkane-1,3-dione-2-spirocyclopropanes from 1,3-cycloalkanediones using (1-aryl-2-bromoethyl)dimethylsulfonium bromides: application to a one-pot synthesis of tetrahydroindol-4(5H)-one

An efficient synthesis of cyclohexane- and cyclopentane-1,3-dione-2-spirocyclopropanes from 1,3-cycloalkanediones using sulfonium salts was achieved. The reaction of 1,3-cycloalkanediones with (1-aryl-2-bromoethyl)dimethylsulfonium bromides and powdered K2CO3 in EtOAc provided the corresponding spirocyclopropanes in high yields. Furthermore, a one-pot synthesis of tetrahydroindol-4(5H)-one from 1,3-cyclohexanedione was achieved by using the present protocol and a sequential ring-opening cyclization of spirocyclopropane with a primary amine

Fibronectin-β1 Integrin Interaction in Teeth

The dental epithelium and extracellular matrix interact to ensure that cell growth and differentiation lead to the formation of teeth of appropriate size and quality. To determine the role of fibronectin in differentiation of the dental epithelium and tooth formation, we analyzed its expression in developing incisors. Fibronectin mRNA was expressed during the presecretory stage in developing dental epithelium, decreased in the secretory and early maturation stages, and then reappeared during the late maturation stage. The binding of dental epithelial cells derived from postnatal day-1 molars to a fibronectin-coated dish was inhibited by the RGD but not RAD peptide, and by a β1 integrin-neutralizing antibody, suggesting that fibronectin-β1 integrin interactions contribute to dental epithelial-cell binding. Because fibronectin and β1 integrin are highly expressed in the dental mesenchyme, it is difficult to determine precisely how their interactions influence dental epithelial differentiation in vivo. Therefore, we analyzed β1 integrin conditional knockout mice (Intβ1lox-/lox-/K14-Cre) and found that they exhibited partial enamel hypoplasia, and delayed eruption of molars and differentiation of ameloblasts, but not of odontoblasts. Furthermore, a cyst-like structure was observed during late ameloblast maturation. Dental epithelial cells from knockout mice did not bind to fibronectin, and induction of ameloblastin expression in these cells by neurotrophic factor-4 was inhibited by treatment with RGD peptide or a fibronectin siRNA, suggesting that the epithelial interaction between fibronectin and β1 integrin is important for ameloblast differentiation and enamel formation

Preparation and Evaluation of Ordinary Attritor Milled Ti-Al Powders and Corresponding Thermal Sprayed Coatings

Ordinary attritor milling of elemental metallic powders under atmospheric condition was utilized to prepare desirable amount of powders for thermal spraying. The effect of different BPR (Ball to Powder weight Ratio) has been investigated in terms of nitridation during milling. To investigate the effect of heat treatment on the formation of dispersed phases, heat treatment to the powder was performed as well. Titanium aluminide coatings with carbonitride dispersed phases were successfully fabricated by low pressure plasma spraying. The hardness and specific wear of the coatings prepared by the powders with different milling conditions was measured so as to investigate the effect of the content of dispersed titanium based carbonitride phases. Experimental results show that the formation of dispersed carbonitride phases depends strongly on milling condition, irrespective of heat treated powders or thermal sprayed coatings, and directly affects the mechanical properties of the coatings. Compared with the phase composition of heated powders and corresponding thermal sprayed coatings, it seems that the temperature of processing the MA powders is also a decisive factor on the phase formation, especially carbonitride phases and oxide phase

シングルセルRNAシーケンシングによる1,25-ジヒドロキシビタミンD3反応性Fgf23発現骨細胞の同定

Fibroblast growth factor 23 (FGF23), a hormone, mainly produced by osteocytes, regulates phosphate and vitamin D metabolism. By contrast, 1,25-dihydroxyvitamin D3, the active form of vitamin D, has been shown to enhance FGF23 production. While it is likely that osteocytes are heterogenous in terms of gene expression profiles, specific subpopulations of Fgf23-expressing osteocytes have not been identified. Single-cell RNA sequencing (scRNA-seq) technology can characterize the transcriptome of an individual cell. Recently, scRNA-seq has been used for bone tissue analysis. However, owing to technical difficulties associated with isolation of osteocytes, studies using scRNA-seq analysis to characterize FGF23-producing osteocytes are lacking. In this study, we characterized osteocytes secreting FGF23 from murine femurs in response to calcitriol (1,25-dihydroxyvitamin D3) using scRNA-seq. We first detected Dmp1, Mepe, and Phex expression in murine osteocytes by in situ hybridization and used these as marker genes of osteocytes. After decalcification, enzyme digestion, and removal of CD45+ cells, femoral bone cells were subjected to scRNA-seq. We identified cell clusters containing osteocytes using marker gene expression. While Fgf23 expression was observed in some osteocytes isolated from femurs of calcitriol-injected mice, no Fgf23 expression was detected in untreated mice. In addition, the expression of several genes which are known to be changed after 1,25-dihydroxyvitamin D3 treatment such as Ccnd2, Fn1, Igfbp7, Pdgfa, and Timp1 was also affected by calcitriol treatment in Fgf23-expressing osteocytes, but not in those lacking Fgf23 expression, even after calcitriol administration. Furthermore, box-and-whisker plots indicated that Fgf23 expression was observed in osteocytes with higher expression levels of the Fam20c, Dmp1, and Phex genes, whose inactivating mutations have been shown to cause FGF23-related hypophosphatemic diseases. These results indicate that osteocytes are heterogeneous with respect to their responsiveness to 1,25-dihydroxyvitamin D3, and sensitivity to 1,25-dihydroxyvitamin D3 is one of the characteristics of osteocytes with Fgf23 expression. It is likely that there is a subpopulation of osteocytes expressing several genes, including Fgf23, involved in phosphate metabolism

Influence of Annealed Aluminum Properties on Adhesion Bonding of Cold Sprayed Titanium Dioxide Coating

It is well known that cold spraying ceramic materials can be difficult because cold spraying requires plastic deformation of the feedstock particles for adhesion to the substrate. The challenge lies in the difficulty of plastically deforming hard and brittle ceramic materials, such as TiO2. Previous studies have reported the possibility of cold spraying thick pure TiO2 but the bonding mechanism of cold sprayed TiO2 is not fully understood. The factor like substrate condition as oxide film thickness and mechanical properties may also affect cold spray deposition but not fully understood in cold spraying ceramic. The aim of the present research is to investigate the correlation between the oxide thickness and substrate deformation with the adhesion strength of cold-sprayed TiO2 coatings toward the bonding mechanism involved. Relevant experiments were executed using Al 1050, subjected to various annealing temperatures and cold-sprayed with TiO2 powder. The results indicate a decreasing trend of coating adhesion strength with increasing annealed substrate temperature from room temperature to 400°C annealed. Metallurgical bonding is pronounced as bonding mechanism involved between TiO2 particle and annealed 1050 substrate

Skeletal FGFR1 signaling is necessary for regulation of serum phosphate level by FGF23 and normal life span

Fibroblast growth factor (FGF) 23 produced by the bone is the principal hormone to regulate serum phosphate level. Serum FGF23 needs to be tightly regulated to maintain serum phosphate in a narrow range. Thus, we hypothesized that the bone has some phosphate-sensing mechanism to regulate the production of FGF23. Previously we showed that extracellular phosphate induces the phosphorylation of FGF receptor 1 (FGFR1) and FGFR1 signaling regulates the expression of Galnt3, whose product works to increase FGF23 production in vitro. In this study, we show the significance of FGFR1 in the regulated FGF23 production and serum phosphate level in vivo. We generated late-osteoblast/osteocyte-specific Fgfr1-knockout mice (Fgfr1fl/fl; OcnCre/+) by crossing the Ocn-Cre and the floxed Fgfr1 mouse lines. We evaluated serum phosphate and FGF23 levels, the expression of Galnt3 in the bone, the body weight and life span. A selective ablation of Fgfr1 aborted the increase of serum active full-length FGF23 and the enhanced expression of Galnt3 in the bone by a high phosphate diet. These mice showed more pronounced hyperphosphatemia compared with control mice. In addition, these mice fed with a control diet showed body weight loss after 23 weeks of age and shorter life span. These results reveal a novel significance of FGFR1 signaling in the phosphate metabolism and normal life span