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Current status of zirconia restoration

Takashi Miyazaki, Takashi Nakamura, Hideo Matsumura, Seiji Ban, Taira Kobayashi
2013 Journal of Prosthodontic Research  
During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and veneering ceramics, (5) bond of zirconia with resin-based luting agents, (6) surface finish of zirconia
more » ... estoration and antagonist enamel wear, and (7) clinical evaluation of zirconia restoration are reviewed. Yttria partially stabilized tetragonal zirconia polycrystalline (Y-TZP) showed better mechanical properties and superior resistance to fracture than other conventional dental ceramics. Furthermore, ceria-stabilized tetragonal zirconia polycrystalline and alumina nanocomposites (Ce-TZP/ A) had the highest fracture toughness and had resistance to low-temperature aging degradation. Both zirconia-based ceramics have been clinically available as an alternative to the metal framework for fixed dental prostheses (FDPs). Marginal adaptation of zirconia-based FDPs is acceptable for clinical application. The most frequent clinical complication with zirconia-based FDPs was chipping of the veneering porcelain that was affected by many factors. The mechanism for the bonding between zirconia and veneering ceramics remains unknown. There was no clear evidence of chemical bonding and the bond strength between zirconia and porcelain was lower than that between metal and porcelain. There were two alternatives proposed that might avoid chipping of veneering porcelains. One was hybrid-structured FDPs comprising CAD/ CAM-fabricated porcelain parts adhering to a CAD/CAM fabricated zirconia framework. Another option was full-contour zirconia FDPs using high translucent zirconia. Combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is currently one of the most reliable bonding systems for zirconia. Adhesive treatments could be applied to luting the restorations and fabricating hybrid-structured FDPs. Full-contour zirconia FDPs caused concern about the wear of antagonist enamel, because the hardness of Y-TZP was over double that of porcelain. However, this review demonstrates that highly polished zirconia yielded lower antagonist wear compared with porcelains. Polishing of zirconia is possible, but glazing is not recommended for the surface finish of zirconia. Clinical data since 2010 are included in this review. The zirconia frameworks rarely got damaged in many cases and complications often occurred in the veneering ceramic materials. Further clinical studies with larger sample sizes and longer follow-up periods are required to investigate the possible influencing factors of technical failures.
doi:10.1016/j.jpor.2013.09.001 pmid:24140561 fatcat:wfo6qrwna5cwppnkxo3wcdlzhm

A review of metaphor research

Tomohiro Taira, Takashi Kusumi
2011 Shrinigaku kenkyu  
The study of the metaphor is interdisciplinary and focuses mostly on three points in cognitive psychology: (a) the cognition of metaphoricity, (b) metaphor comprehension processes, and (c) the reason why one concept is represented by another concept as a metaphor. This article reviews the history of research on the metaphor from these three perspectives. Most recent studies support the following viewpoints. Metaphor comprehension is as quick and automatic as literal comprehension. Metaphor
more » ... ehension entails the processes of comparison and abstraction. The reason why one concept is compared with another concept is strongly related with the motivation process of combination between different concepts such as embodied cognition.
doi:10.4992/jjpsy.82.283 pmid:21919307 fatcat:dvcgdleznbczdojvslh5d4qmg4

Factors Associated with Longer Transportation Time to North American Style Emergency Department in Japan

Takashi Shiga, Taku Taira, Yasuhiko Taira, Shigeki Fujitani
2019 Journal of St Marianna University  
Japanese emergency departments have traditionally been separated into tertiary and secondary centers. Tertiary emergency centers focus on the care of trauma and critically ill patients, while secondary emergency centers operate with limited resources and only accept patients of a limited acuity from emergency medical services (EMS). In contrast, North American-style Emergency Departments (NAED) have been developed, with the aim of accepting both critical and non-critical patients. We conducted
more » ... retrospective, observational study using municipal EMS records from 2012 in a Japanese city. Our aim was to identify patient characteristics associated with long EMS transportation times to NAED in an urban city where both traditional and NAED centers are available. The primary endpoint was long transportation time, defined as >35 minutes. Other items included the distance of transportation from the scene (km), age, sex, reason for transportation (medical or surgical), relevant specialty determined by EMS, condition severity, number of EMS negotiations until acceptance, and the reason for diversion by other hospitals. Multivariate logistic regression was used to find characteristics associated with long transportation time. A total of 2934 patients were included in the analysis. Median transportation time was 29 minutes (IQR 21-38). Characteristics that were associated with long transportation time included age (years) (OR, 1.02; 95%CI, 1.02-1.03; P<0.01), patients with orthopedic (OR, 1.69; 95%CI, 1.08-2.66; P=0.02) or neurosurgical (OR, 1.72; 95%CI, 1.21-2.47; P<0.01) conditions, and the number of EMS negotiations until acceptance (OR, 4.08; 95%CI, 3.12-5.33; P<0.01). Long transportation times were negatively associated with patients with medical (OR, 0.66; 95%CI, 0.46-0.96; P=0.03) and ear nose and throat (ENT) (OR, 0.13; 95%CI, 0.04-0.44; P<0.01) conditions. This is likely because the NAEDs fill an unmet need for patients that require certain types of care, such as surgical or neurosurgical treatment, or because they accept patients that have been refused by other centers.
doi:10.17264/stmarieng.10.89 fatcat:xo7engbhjrebfhkzcpcr6tp3bu

A sixth sense

Hidetsugu Komeda, Tomohiro Taira, Kohei Tsunemi, Takashi Kusumi, David N. Rapp
2018 Scientific Study of Literature  
Stories with twist endings are popular, but little research has examined how readers experience them. To begin developing such an account, we examined the affective responses that emerge during stories with twist endings. In Experiment 1, 28 Japanese participants read a story with a twist ending. Greater empathy and stronger expectations were associated with slower reading times during participants' first reading of the story. However, on participants' second reading, greater empathy and
more » ... r expectations were associated with faster reading times. In Experiment 2, we tested the generality of these effects by asking 36 English-speaking participants to read four stories with twist endings. The results were similar to Experiment 1. Readers' initial and recurring responses to stories with twist endings reflect changes in surprise and empathy. These feelings underlie engagement with and interest in unexpected and often incoherent contents, which are characteristics of stories with twist endings.
doi:10.1075/ssol.17002.kom fatcat:2xxoidmo7fcn5kn65q47kc56jy

Hyperglycemia and chorea

Masahiro Kashiura, Haruka Taira, Shunsuke Amagasa, Takashi Moriya
2018 Journal of General and Family Medicine  
An 87-year-old female who had insulin-dependent diabetes mellitus with a glycated hemoglobin level of 8.5% presented with altered consciousness due to hyperosmolar hyperglycemic state with blood glucose concentration of 1125 mg/dL and serum osmolality of 341 mOsm/L. One week after the treatment of the hyperglycemia, involving intravenous fluid administration, continuous infusion of This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License,
more » ... which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. KASHIURA et Al. insulin, and correction of electrolyte imbalances, the patient gradually regained consciousness but experienced involuntary movements of the right upper limb. Physical examination revealed right semidirected, nonrhythmic, irregular, and twisting movements, consistent with hemichorea (Video S1). A brain computed tomography showed no abnormal findings ( Figure 1A ). Magnetic resonance imaging of the brain showed a T1-weighted area of hyperintensity and a T2*weighted area of hypointensity in the left caudate nucleus, and a part of the left putamen and globus pallidus, sparing the internal capsule ( Figure 1B , arrow; and Figure 1C , arrowhead), with normal findings of T2-weighted images ( Figure 1D ). We diagnosed diabetic chorea in this patient based on the clinical course and image findings. The patient's symptoms improved following the administration of haloperidol for a total of 2 months for early symptom control, without recurrence of the hemichorea during the entire follow-up period of 4 months. Her diabetic control was good with intensive insulin therapy. Diabetic chorea is a neurological complication of hyperglycemia, such as hyperosmolar hyperglycemic state and diabetic ketoacidosis. The symptom improves with treatment of hyperglycemia in most cases. In addition, treatment includes not only dopamine antagonists such as haloperidol, but also tetrabenazine or topiramate. 1,2 CO N FLI C T O F I NTE R E S T The authors have stated explicitly that there are no conflicts of interest in connection with this article. O RCI D
doi:10.1002/jgf2.174 pmid:29998046 pmcid:PMC6030040 fatcat:d4at3uempfgxhlzgpomwj2prey

Lipid Peroxide Levels in Tissues of Live Fish

Takashi Nakamura, Ryusuke Tanaka, Yoshikazu Higo, Kiyoto Taira, Tatsusuke Takeda
1998 Fisheries Science  
Steady-state levels of lipid peroxide (LPO) in lateral muscles and liver of normal live fish, their ele vation induced by xenobiotics and the distribution in lipid class were studied using yellowtail, red sea bream, carp, sweet fish, etc. LPO levels expressed in terms of meq/kg lipid , so to speak peroxide value (PV), vary in inverse proportion to the lipid contents; the higher the lipid content the lower the PV. Thus, PVs in live fish fluctuate with lipid contents. On the other hand, LPO
more » ... expressed in terms of nmol/g tissue showed a steady-state reflecting physiological activity of tissue; 100-200 nmol/g tissue in liver and dark muscle, and lower than 50 nmol/g tissue inordinary muscle. The levels was elevated by abdominal injection of CC14 and a bacterial culture. In lipids of wild yellowtail tissues, nearly the same total amounts of LPO were distributed in neutral lipid and phospholipid fractions.
doi:10.2331/fishsci.64.617 fatcat:jazh2unqe5e57dybk7p4gmrqiq

Recombinant Tol2 transposase with activity inXenopusembryos

Takashi Shibano, Masatoshi Takeda, Isao Suetake, Koichi Kawakami, Makoto Asashima, Shoji Tajima, Masanori Taira
2007 FEBS Letters  
The Tol2 transposon system is a useful gene transduction technique, but the injection of mRNA is not sufficiently effective in Xenopus embryos to express Tol2 transposase (Tol2TP). To overcome this, we bacterially synthesized recombinant Tol2TP (rTol2TP) protein and showed that rTol2TP efficiently excised the Tol2 element from an injected donor plasmid in Xenopus embryos. Furthermore, injected embryos exhibited uniform and ubiquitous expression of an EGFP reporter gene placed within the Tol2
more » ... ment. Importantly, size-exclusion chromatography suggests that rTol2TP forms a tetramer, which differs from the reported hexamer formed by Hermes transposase, although both belong to the same hAT family. The use of rTol2TP may facilitate efficient gene transduction in Xenopus, and the biochemical characterization of Tol2TP.
doi:10.1016/j.febslet.2007.08.004 pmid:17716667 fatcat:g4ax3mykz5hr5pu6pgj4sgqsgm

Nuclease-resistant chimeric ribozymes containing deoxyribonucleotides and phosphorothioate linkages

Takashi Shimayama, Fumiko Nishikawa, Satoshi Nishikawa, Kazunari Taira
1993 Nucleic Acids Research  
Hammerhead ribozymes are considered to be potential therapeutic agents for HIV virus because of their sitespecific RNA cleavage activities. In order to elucidate structurefunction relationship and also to hopefully endow ribozymes with resistance to ribonucleases, we firstly synthesized chimeric DNA/RNA ribozymes in which deoxyribonucleotides were substituted for ribonucleotides at noncatalytic residues (stems 1, 11, and 111). Kinetic analysis revealed that (i) DNA in the hybridizing arms
more » ... I and 111) enhanced the chemical cleavage step. (ii) stem 11 and its loop do not affect its enzymatic activity. Secondly, we introduced deoxyribonucleotides with phosphorothioate linkages to the same regions (stems 1, 11, and 111) in order to test whether such thio-linkages further improve their resistance to nucleases. Kinetic measurements revealed that this chimeric thio-DNA/RNA ribozyme had seven-fold higher cleavage activity (k,at = 27 min-1) than that of the all-RNA ribozyme. In terms of stability in serum, DNA-armed ribozymes gained about 10-fold higher stability in human serum but no increase in stability was recognized in bovine serum, probably because the latter serum mainly contained endoribonucleases that attacked unmodified catalyticloop regions of these ribozymes. Thirdly, in order to protect them from endoribonucleases, three additional modifications were made at positions U7, U4 and C3 within the internal catalytic-loop region, that succeeded in gaining more than a hundred times greater resistance to nucleases in both serums. More importantly, these catalytic-loop modified ribozymes had the comparable cleavage activity (kca) to the wildtype ribozyme. Since these chimeric thio-DNA/RNA ribozymes are more resistant to attack by both exonucleases and endoribonucleases than the wildtype all-RNA ribozymes in vivo and since their cleavage activities are not sacrificed, they appear to be better candidates than the wild type for antiviral therapeutic agents.
doi:10.1093/nar/21.11.2605 pmid:8332458 pmcid:PMC309588 fatcat:zqnetxpgynatllkiegozh6hf5e

Countermeasure against indoor air pollution using charcoal board

Takashi Asada, Akifumi Yamada, Shigehisa Ishihara, Toru Komatsu, Ryusuke Nishimaki, Tatsu Taira, Kikuo Oikawa
2004 TANSO  
doi:10.7209/tanso.2004.10 fatcat:hdvq625henbuheplxix5vtdnqu

Viscoelastic behavior of commercially available tissue conditioners under compression

Setsuo SAITOH, Kaori SASAKI, Takashi NEZU, Masayuki TAIRA
2010 Dental materials journal  
Three commercially available tissue conditioners -Tissue conditioner II (STII), Tissue conditioner (GTC), and Tissue Care (TTC)were tested using a rheometer to evaluate their viscoelasticity under compression at a constant distortion (10%). Immediately after fabrication, STII showed the highest hardness and compressive modulus of elasticity, followed by TTC and GTC. TTC showed the highest relaxation rate, followed by GTC and STII. STII and GTC showed equivalent relaxation times, while TTC
more » ... the shortest relaxation time. The modulus of viscosity was highest in STII, followed by GTC and TTC. The immersion of each sample in water resulted in increases in hardness, compressive modulus of elasticity, relaxation time, and modulus of viscosity and decreases in relaxation rates. The three products have different viscoelastic properties. Further, the results indicate that STII and GTC exhibit better performance when used as functional impression materials, while TTC exhibits better performance when used as a tissue conditioner.
doi:10.4012/dmj.2009-130 fatcat:2alx6jn67jchfeci43dtpwsn6e

A Novel Branching Enzyme of the GH-57 Family

Tamotsu Kanai, Taira Murakami, Hiroki Takata, Takashi Kuriki, Tadayuki Imanaka
2007 Journal of Applied Glycoscience  
doi:10.5458/jag.54.119 fatcat:lz7la6lowfdgxcoonstijzxy3y

Expert system for blast furnace operation at Kimitsu works

Shigeru Amano, Tsuyoshi Takarabe, Takashi Nakamori, Hiroshi Oda, Masamichi Taira, Satoshi Watanabe, Takatoshi Seki
1990 ISIJ International  
The experience and knowledge of operators are important for operation control of blast furnaces. A knowledge engineering or expert system that can represent this empirical knowledge was practically applied to Nos. 3 and 4 blast furnaces at Kimitsu Works, Nippon Steel Corp. In the development of the knowledge base for the expert system, the knowledge of the most experienced operators was represented by a hypothetical inference method composed of the sensor information judgement, interim
more » ... , final judgement and action stages. Theexpert system was implemented with emphasis placed on its maintainability by operators. Among the measures taken to this end are the adoption of a Japanese production language, augmentation of indication of inferred result, and installation of oft-line terminals for modifying and test running the knowledgebase. As a result of these efforts, the expert system can be largely operated and controlled by the field personnel. Since the expert system was brought on-line, periodic study meetings have been evaluating its performance and updating the knowledge base. The expert system is utilized in the actual operation control of the two blast furnaces at a high rate and the blast furnaces are stably operated.
doi:10.2355/isijinternational.30.105 fatcat:5yimikwkzfd5ffflsdzawmm3ji

日本鉄鋼協会第64回講演大会講演大要

Taira NAKANO, Tsugio KANEDA, Tamotsu HIURA, Takashi YONEDA
1962 Tetsu to hagane  
doi:10.2355/tetsutohagane1955.48.11_1427 fatcat:pp6fdz5mxrhq5aoemxczauktbe

Development of On-line Fineness Meter

Youji KAWAMURA, Taira ASO, Takashi NUMATA
1977 Journal of the Research Association of Powder Technology Japan  
川 村 洋 二* 麻 生 平* 沼 田 孝** Youji Kawamura Taira Aso Takashi Numata 1. ま え が き セ メ ン ト製 造 工 程 は 焼 成 工 程 と粉 砕 工 程 に 大 別 で き る 。  ... 
doi:10.4164/sptj1964.14.195 fatcat:x63ejeeakjgsza7kcmfgr6zsgi

比喩理解における親しみやすさと解釈の多様性
Metaphor Familiarity and Interpretation Diversity

Tomohiro Taira, Keiko Nakamoto, Takashi Kusumi
2007 Cognitive Studies  
(2001) Bowdle & Gentner (2005 Metaphor Familiarity and Interpretation Diversity, by Tomohiro Taira (Graduate School of Education, Kyoto University & Japan Society for Promotion of Science), Keiko  ...  Nakamoto (Faculty of Education, Bunkyo University), and Takashi Kusumi (Graduate School of Education, Kyoto University). 1. 1 1.1 Gentner, Bow- dle, Wolff, & Boronat (2001) (Alignment Process  ... 
doi:10.11225/jcss.14.322 fatcat:6a4akmvrr5gxrjxpsu4sp3vaki
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