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Search Results: 1 - 10 of 1480 matches for " Nobuaki Yamaguchi "
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Synthesis of CaO-SiO2 Compounds Using Materials Extracted from Industrial Wastes  [PDF]
Nobuaki Yamaguchi, Yoshiko Masuda, Yoshishige Yamada, Hideaki Narusawa, Cho Han-Cheol, Yukimichi Tamaki, Takashi Miyazaki
Open Journal of Inorganic Non-metallic Materials (OJINM) , 2015, DOI: 10.4236/ojinm.2015.51001
Abstract: Mineral trioxide aggregate (MTA) cement is an attractive material in endodontic dentistry. The purpose of this study was to produce calcium silicate, which is a major component of MTA, from waste materials. A dental alginate impression gel and used chalks were selected and mixed in a suitable ratio (Code: EXP). As a control, CaCO3 and a commercial diatomite were used (Code: CON). Each powder was heated to 850C and 1000C, and then kneaded with water. TG-DTA, compressive tests, SEM observations, elemental mapping analyses, and XRD analyses were performed. TG-DTA indicated that weight reduction of CaCO3 started at 600C, and it completely decomposed on heating at 850C. The strength was affected by the temperature. After heating, CaCO3 was transformed into CaO and/or Ca2SiO4, and Ca(OH)2 was formed by mixing with water. There were no differences between EXP and CON. These data suggested that recycled wastes might be promising MTA sources.
Visualization of odor-induced neuronal activity by immediate early gene expression
Bepari Asim K,Watanabe Keisuke,Yamaguchi Masahiro,Tamamaki Nobuaki
BMC Neuroscience , 2012, DOI: 10.1186/1471-2202-13-140
Abstract: Background Sensitive detection of sensory-evoked neuronal activation is a key to mechanistic understanding of brain functions. Since immediate early genes (IEGs) are readily induced in the brain by environmental changes, tracing IEG expression provides a convenient tool to identify brain activity. In this study we used in situ hybridization to detect odor-evoked induction of ten IEGs in the mouse olfactory system. We then analyzed IEG induction in the cyclic nucleotide-gated channel subunit A2 (Cnga2)-null mice to visualize residual neuronal activity following odorant exposure since CNGA2 is a key component of the olfactory signal transduction pathway in the main olfactory system. Results We observed rapid induction of as many as ten IEGs in the mouse olfactory bulb (OB) after olfactory stimulation by a non-biological odorant amyl acetate. A robust increase in expression of several IEGs like c-fos and Egr1 was evident in the glomerular layer, the mitral/tufted cell layer and the granule cell layer. Additionally, the neuronal IEG Npas4 showed steep induction from a very low basal expression level predominantly in the granule cell layer. In Cnga2-null mice, which are usually anosmic and sexually unresponsive, glomerular activation was insignificant in response to either ambient odorants or female stimuli. However, a subtle induction of c-fos took place in the OB of a few Cnga2-mutants which exhibited sexual arousal. Interestingly, very strong glomerular activation was observed in the OB of Cnga2-null male mice after stimulation with either the neutral odor amyl acetate or the predator odor 2, 3, 5-trimethyl-3-thiazoline (TMT). Conclusions This study shows for the first time that in vivo olfactory stimulation can robustly induce the neuronal IEG Npas4 in the mouse OB and confirms the odor-evoked induction of a number of IEGs. As shown in previous studies, our results indicate that a CNGA2-independent signaling pathway(s) may activate the olfactory circuit in Cnga2-null mice and that neuronal activation which correlates to behavioral difference in individual mice is detectable by in situ hybridization of IEGs. Thus, the in situ hybridization probe set we established for IEG tracing can be very useful to visualize neuronal activity at the cellular level.
Matrix Isolation and Computational Study on the Photolysis of CHCl2COCl  [PDF]
Nobuaki Tanaka
Open Journal of Physical Chemistry (OJPC) , 2014, DOI: 10.4236/ojpc.2014.43014
Abstract:

UV light photolysis of dichloroacetyl chloride (CHCl2COCl) has been investigated by infrared spectroscopy in cryogenic Ar, Kr, Xe, and O2 matrices. The formation of CHCl3 and CO was found to be the dominant process over the ketene formation. The C-C bond cleaved products CHCl2 and COCl were also observed. As the number of the chlorine atom substitution to methyl group of acetyl chloride increased, the C-C bond cleaved product yield in the triplet state increased, which can be attributed to an internal heavy-atom effect where the intersystem crossing rate was enhanced.

Matrix Metalloproteinase-3 in Odontoblastic Cells Derived from Ips Cells: Unique Proliferation Response as Odontoblastic Cells Derived from ES Cells
Taiki Hiyama, Nobuaki Ozeki, Makio Mogi, Hideyuki Yamaguchi, Rie Kawai, Kazuhiko Nakata, Ayami Kondo, Hiroshi Nakamura
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0083563
Abstract: We previously reported that matrix metalloproteinase (MMP)-3 accelerates wound healing following dental pulp injury. In addition, we reported that a proinflammatory cytokine mixture (tumor necrosis factor-α, interleukin (IL)-1β and interferon-γ) induced MMP-3 activity in odontoblast-like cells derived from mouse embryonic stem (ES) cells, suggesting that MMP-3 plays a potential unique physiological role in wound healing and regeneration of dental pulp in odontoblast-like cells. In this study, we tested the hypothesis that upregulation of MMP-3 activity by IL-1β promotes proliferation and apoptosis of purified odontoblast-like cells derived from induced pluripotent stem (iPS) and ES cells. Each odontoblast-like cell was isolated and incubated with different concentrations of IL-1β. MMP-3 mRNA and protein expression were assessed using RT-PCR and western blotting, respectively. MMP-3 activity was measured using immunoprecipitation and a fluorescence substrate. Cell proliferation and apoptosis were determined using ELISA for BrdU and DNA fragmentation, respectively. siRNA was used to reduce MMP-3 transcripts in these cells. Treatment with IL-1β increased MMP-3 mRNA and protein levels, and MMP-3 activity in odontoblast-like cells. Cell proliferation was found to markedly increase with no changes in apoptosis. Endogenous tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were constitutively expressed during all experiments. The exocytosis inhibitor, Exo1, potently suppressed the appearance of MMP-3 in the conditioned medium. Treatment with siRNA against MMP-3 suppressed an IL-1β-induced increase in MMP-3 expression and activity, and also suppressed cell proliferation, but unexpectedly increased apoptosis in these cells (P<0.05). Exogenous MMP-3 was found to induce cell proliferation in odontoblast-like cells derived from iPS cells and ES cells. This siRNA-mediated increase in apoptosis could be reversed with exogenous MMP-3 stimulation (P<0.05). Taken together, IL-1β induced MMP-3-regulated cell proliferation and suppressed apoptosis in odontoblast-like cells derived from iPS and ES cells.
Mouse-Induced Pluripotent Stem Cells Differentiate into Odontoblast-Like Cells with Induction of Altered Adhesive and Migratory Phenotype of Integrin
Nobuaki Ozeki, Makio Mogi, Rie Kawai, Hideyuki Yamaguchi, Taiki Hiyama, Kazuhiko Nakata, Hiroshi Nakamura
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080026
Abstract: Methods for differentiating induced pluripotent stem (iPS) cells into odontoblasts generally require epithelial–mesenchymal interactions. Here, we sought to characterize the cells produced by a ‘hanging drop’ technique for differentiating mouse iPS cells into odontoblast-like cells that requires no such interaction. Cells were cultured by the hanging drop method on a collagen type-I (Col-I) scaffold (CS) combined with bone morphogenetic protein (BMP)-4 (CS/BMP-4) without an epithelial–mesenchymal interaction. We evaluated the expression of odontoblast-related mRNA and protein, and the proliferation rate of these cells using reverse-transcription polymerase chain reaction, immunofluorescence staining, and BrdU cell proliferation enzyme-linked immunosorbent assay, respectively. The differentiated cells strongly expressed the mRNA for dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (Dmp-1), which are markers of mature odontoblasts. Osteopontin and osteocalcin were not expressed in the differentiated cells, demonstrating that the differentiated iPS cells bore little resemblance to osteoblasts. Instead, they acquired odontoblast-specific properties, including the adoption of an odontoblastic phenotype, typified by high alkaline phosphatase (ALP) activity and calcification capacity. The cell-surface expression of proteins such as integrins α2, α6, αV and αVβ3 was rapidly up-regulated. Interestingly, antibodies and siRNAs against integrin α2 suppressed the expression of DSPP and Dmp-1, reduced the activity of ALP and blocked calcification, suggesting that integrin α2 in iPS cells mediates their differentiation into odontoblast-like cells. The adhesion of these cells to fibronectin and Col-I, and their migration on these substrata, was significantly increased following differentiation into odontoblast-like cells. Thus, we have demonstrated that integrin α2 is involved in the differentiation of mouse iPS cells into odontoblast-like cells using the hanging drop culture method, and that these cells have the appropriate physiological and functional characteristics to act as odontoblasts in tissue engineering and regenerative therapies for the treatment of dentin and/or dental pulp damage.
Assessing Material Qualities and Efficiency Limits of III-V on Silicon Solar Cells Using External Radiative Efficiency
Kan-Hua Lee,Kenji Araki,Li Wang,Nobuaki Kojima,Yoshio Ohshita,Masafumi Yamaguchi
Physics , 2015,
Abstract: The paper presents a quantitative approach to investigate and compare the material qualities of III-V on silicon (III-V/Si) solar cells by using external radiative efficiencies. We use this analysis to predict the limiting efficiencies and evaluate the criteria of material quality in order to achieve high efficiency III-V/Si solar cells. This result also yields several implications of designing high efficiency III-V/Si solar cells.
Density Functional Theory Studies on the Addition and Abstraction Reactions of OH Radical with Benzoate Anion  [PDF]
Nobuaki Tanaka, Shigeo Itoh
Open Journal of Physical Chemistry (OJPC) , 2013, DOI: 10.4236/ojpc.2013.31002
Abstract:

The addition and abstraction reactions of OH radical with benzoate anion are investigated by density functional theory calculations that include solvent effects using UB3LYP, UCAM-B3LYP, UmPW1PW91 and UM06-2X functionals with the 6-311++G(2d,2p) basis set. Geometry optimizations of the reactants, products and transition state species are performed for the possible reaction paths. For the addition reactions, those targeting the ipso-, ortho-, meta- and para-carbons are predicted to be exoergic. The H-atom abstraction reactions from ortho, meta and para positions are also predicted to be exoergic. On the basis of the rate constants calculated by means of the transition state theory, the H-atom abstraction reaction from the ortho position is determined to be the favored path followed by the ortho OH addition reaction.

The Acquisition of Complex Structures: The Case of Child ESL  [PDF]
Yumiko Yamaguchi
Open Journal of Modern Linguistics (OJML) , 2013, DOI: 10.4236/ojml.2013.33030
Abstract:

This study examines how complex linguistic structures are acquired in child English as a second language. The spontaneous speech producing by a Japanese primary school child, learning English in a naturalistic environment, was audio-recorded regularly over two years and the development of complex syntactic structures containing subordinate clauses was compared with the acquisition of other English morphosyntactic structures as represented within Processability Theory (PT) (Pienemann, 1998; Pienemann, Di Biase, & Kawaguchi, 2005). Although PT predicts that subordination is acquired at the highest stage in processability hierarchy, the results in this longitudinal study show that some of the subordinate constructions emerge at earlier stages in child ESL acquisition.

Immunohistochemical Characteristics of IgG4-Related Tubulointerstitial Nephritis: Detailed Analysis of 20 Japanese Cases
Mitsuhiro Kawano,Ichiro Mizushima,Yutaka Yamaguchi,Naofumi Imai,Hitoshi Nakashima,Shinichi Nishi,Satoshi Hisano,Nobuaki Yamanaka,Motohisa Yamamoto,Hiroki Takahashi,Hisanori Umehara,Takao Saito,Takako Saeki
International Journal of Rheumatology , 2012, DOI: 10.1155/2012/609795
Abstract: Although tubulointerstitial nephritis with IgG4+ plasma cell (PC) infiltration is a hallmark of IgG4-related kidney disease (IgG4-RKD), only a few studies are available about the minimum number of IgG4+?PC needed for diagnosis along with IgG4+/IgG+?PC ratio in the kidney. In addition, the significance of the deposition of IgG or complement as a reflection of humoral immunity involvement is still uncertain. In this study, we analyzed 20 Japanese patients with IgG4-RKD to evaluate the number of IgG4+?PCs along with IgG4+/IgG+?PC ratio and involvement of humoral immunity. The average number of IgG4+?PCs was 43.8/hpf and the average IgG4+/IgG+ or IgG4+/CD138+ ratio was 53%. IgG and C3 granular deposits on the tubular basement membrane (TBM) were detected by immunofluorescence microscopy in 13% and 47% of patients, respectively. Nine patients had a variety of glomerular lesions, and 7 of them had immunoglobulin or complement deposition in the glomerulus. In conclusion, we confirmed that infiltrating IgG4+?PCs > 10/hpf and/or IgG4/IgG (CD138)+?PCs > 40% was appropriate as an item of the diagnostic criteria for IgG4-RKD. A relatively high frequency of diverse glomerular lesions with immunoglobulin or complement deposits and deposits in TBM may be evidence of immune complex involvement in IgG4-related disease. 1. Introduction The main histopathological finding in the kidney of IgG4-RD is tubulointerstitial nephritis (TIN) [1–3], which may result in renal failure [4]. IgG4-related TIN is composed of dense lymphoplasmacytic infiltrates with fibrosis and copious IgG4+ plasma cell infiltration, which are common features shared by other involved organs [5], and these common pathologic features in the kidney have clearly been described by previous studies [1–3]. However, the minimum number of IgG4+ plasma cells needed for diagnosis has been differently reported in each affected organ [6–9], and only a few studies are available about the actual number of IgG4+ plasma cells evaluated along with IgG4+/IgG+ plasma cell ratio in IgG4-related kidney disease (IgG4-RKD) [2]. In addition to this issue, case reports or case series of a variety of glomerular disease concurrent with TIN have been accumulated [10–26]. These glomerular lesions are frequently accompanied by immunoglobulin or complement deposits suggesting that immune complexes might be involved in the pathogenesis of some cases with IgG4-RKD [2, 3]. However, the significance of these glomerular lesions as a reflection of humoral immunity involvement is still uncertain, and whether these glomerular lesions represent
Selective Chemical Labeling of Proteins with Small Fluorescent Molecules Based on Metal-Chelation Methodology
Nobuaki Soh
Sensors , 2008, DOI: 10.3390/s8021004
Abstract: Site-specific chemical labeling utilizing small fluorescent molecules is apowerful and attractive technique for in vivo and in vitro analysis of cellular proteins,which can circumvent some problems in genetic encoding labeling by large fluorescentproteins. In particular, affinity labeling based on metal-chelation, advantageous due to thehigh selectivity/simplicity and the small tag-size, is promising, as well as enzymaticcovalent labeling, thereby a variety of novel methods have been studied in recent years.This review describes the advances in chemical labeling of proteins, especially highlightingthe metal-chelation methodology.
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