• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1997.10a
• /
• pp.187-187
• /
• 1997

Silicon nitride is the most excellent materials among structural ceramics. It has been reported that fracture toughness was improved with adding second phase particles, whisker, fiber etc. However, containing of second phase particles enhanced fracture toughness, however flexural strength was degraded. As adding nanosize SiC particles into silicon nitride, the physical properties of fluxural strength, fracture toughness, the modulus of elasticity. In this study, 2wt% $Al_2$O$_3$ and 4 wt% $Y_2$O$_3$ were added into UBE E-10 and 0, 10, 20, 30, 40, 50 vol% nano-SiC powder (Sumitomo T1 powder) were added, respectively. It is hot pressed at 185$0^{\circ}C$ for 1 hour. Most of structural ceramics for engineering application are wear resistance. In this study, wear behaviors (in water) of silicon nitride with varying the amount of nano-size silicon carbide were investigated, and was compared to physical properties. Simultaneously wear mechanism will be found out.

• Fisheries and Aquatic Sciences
• /
• v.19 no.4
• /
• pp.21.1-21.11
• /
• 2016

Background: The evaluation of suitable reference genes as normalization controls is a prerequisite requirement for launching quantitative reverse transcription-PCR (RT-qPCR)-based expression study. In order to select the stable reference genes in abalone Haliotis discus hannai tissues (gill and hepatopancreas) under heavy metal exposure conditions (Cu, Zn, and Cd), 12 potential candidate housekeeping genes were subjected to expression stability based on the comprehensive ranking while integrating four different statistical algorithms (geNorm, NormFinder, BestKeeper, and ${\Delta}CT$ method). Results: Expression stability in the gill subset was determined as RPL7 > RPL8 > ACTB > RPL3 > PPIB > RPL7A > EF1A > RPL4 > GAPDH > RPL5 > UBE2 > B-TU. On the other hand, the ranking in the subset for hepatopancreas was RPL7 > RPL3 > RPL8 > ACTB > RPL4 > EF1A > RPL5 > RPL7A > B-TU > UBE2 > PPIB > GAPDH. The pairwise variation assessed by the geNorm program indicates that two reference genes could be sufficient for accurate normalization in both gill and hepatopancreas subsets. Overall, both gill and hepatopancreas subsets recommended ribosomal protein genes (particularly RPL7) as stable references, whereas traditional housekeepers such as ${\beta}-tubulin$ (B-TU) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were ranked as unstable genes. The validation of reference gene selection was confirmed with the quantitative assay of MT transcripts. Conclusions: The present analysis showed the importance of validating reference genes with multiple algorithmic approaches to select genes that are truly stable. Our results indicate that expression stability of a given reference gene could not always have consensus across tissue types. The data from this study could be a good guide for the future design of RT-qPCR studies with respect to metal regulation/detoxification and other related physiologies in this abalone species.

• Proceedings of the Korean Society for Environmental Edudation Conference
• /
• 2003.07a
• /
• pp.50-56
• /
• 2003

＃1 The Education from our Environment, The urgent subject for survival and prosperity in the future. - Around Yamaguchi in japan. - ＃2 Days of tour : January, 15, 2003 - January, 28, 2003 ＊ Comprehensive classes involved in ecosystems; Ryojo Elementary school, Guina Elementary school, Dabusei Junior High School, Ube Technical High School, Yashiro Elementary School, Toyota Nishi Junior High School, Seii Elementary School, Yamaguchi Prefectural School for the Mentally Impaired, Yamaguchi Institute for Educational Research and In-service Training, Kirara Beach Nature Watching Park ＃3 Characteristics of Yamaguchi Prefectural Environmental Education - Constant effort by concerned authorities and dedicated teachers - Cooperation of schools with community - Application of the comprehensive classes - Student-centered education through experiences - Acquirement of basic knowledge on environment in their daily lives - The harmony with the ability to survive' ＃4 Characteristics of the environmental education in each school $\square$ Ryojo Elementary School \longrightarrow Breeding the fireflies' larvae and releasing them into nature $\square$ Kuina Elementary School \longrightarrow Keeping the rivers clean $\square$ Yashiro Elementary School \longrightarrow Learning through exploring ‘Akiyoshido Cave’ $\square$ Seii Elementary School \longrightarrow Tree-planting campaign continued for 30 years $\square$ Tabuse Junior High School \longrightarrow Making their village good to live in $\square$ Toyota-Nishi Junior High School \longrightarrow Learning through working on the farm and in the forests $\square$ Ube Technical High School \longrightarrow Purifying the pond by the ‘biotope’ ＃5 Focus on Yashiro Elementary School \longrightarrow Children Guide Activity (25 hours annually) * To love their native place and tourists' attraction, Akiyoshidal * To introduce a variety of local events; - To make a fire in the mountains - To explore the cave - To hold a festival for tourists - To have a family-jointed bike riding ＃6 $\square$ conclusion - Gradual extension of environmental education * individuals \longrightarrow school \longrightarrow community - Finding the environmental problems around themselves and relating them with features of their community < Tips for the environmental education in the future > - Need for encouragement of more lively discussion in class - Expansive application of comprehensive classes to various areas

• IEMEK Journal of Embedded Systems and Applications
• /
• v.2 no.2
• /
• pp.76-81
• /
• 2007

A novel multi-layer type micro gas sensor for $NO_X$ detection was designed and fabricated. Micro platform defined as type II-1 in this article for micro gas sensor was fabricated using the MEMS technology to meet the demanding needs of lower power consumption. Nano composite materials were fabricated with nanosized tin oxide powder and $\underline{m}$ulti-$\underline{w}$all $\underline{c}$arbon $\underline{n}$ano $\underline{t}$ube (MWCNT) to improve sensitivity. We investigated characteristics of fabricated multi-layer type micro gas sensor with $NO_2$ concentration variations at constant 2.2 V. Sensitivity (S) of micro gas sensor were observed to increase from 2.9, to 7.4 and 11.2 as concentrations of $NO_2$ gases increased from 2.4 ppm, to 3.6 ppm and 4.9 ppm. When 2.4 ppm of $NO_2$ gas was applied, response time and recovery time of micro gas sensor were recorded as 101 seconds and 142 seconds, respectively.

• Journal of Ecology and Environment
• /
• v.41 no.3
• /
• pp.45-53
• /
• 2017

Background: There have been many studies on the growth conditions of Zostera marina and Zostera japonica, but few studies have examined how spatial and temporal factors affect growth in established seagrass beds or the distribution range and shoot density. This study aims to clarify the factors that determine the temporal and spatial distribution of Zostera marina and Zostera japonica in the Seto Inland Sea east of Yamaguchi Prefecture. Methods: The study site is in Hiroshima Bay of the Seto Inland Sea, along the east coast of Yamaguchi Prefecture, Japan. We monitored by diving observation to confirm shoot density, presence or absence of both species and observed water temperature, salinity by sensor in study sites. Results: The frequency of occurrence of Zostera marina was high in all seasons, even in water depths of D.L. + 1 to -5 m ($80{\pm}34%$ to $89{\pm}19%$; mean ${\pm}$ standard deviation), but lower (as low as $43{\pm}34%$) near the breakwall, where datum level was 1 to 2 m, and it was further reduced in datum level -5 m and deeper. The frequency of occurrence of Zostera japonica was highest in water with a datum level of +1 to 0 m. However, in datum level of 0 m or deeper, it became lower as the water depth became deeper. Datum level +1 m to 0 m was an optimal water depth for both species. The frequency of occurrence and the shoot density of both species showed no negative correlation. In 2011, the daily mean water temperature was $10^{\circ}C$ or less on more days than in other years and the feeding damage by S. fuscescens in the study sites caused damage at the tips. Conclusions: We considered that the relationship between these species at the optimal water depth was not competitive, but due to differences in spatial distribution, Zostera marina and Zostera japonica do not influence each other due to temperature conditions and feeding damage and other environmental conditions. Zostera japonica required light intensity than Zostera marina, and the water depth played an important role in the distribution of both species.

• Journal of Animal Reproduction and Biotechnology
• /
• v.34 no.4
• /
• pp.280-291
• /
• 2019

Potential utility of 14 candidate housekeeping genes as normalization reference for RT-qPCR analysis with developmental samples (fertilized eggs to late veliger larvae) in Pacific abalone Haliotis discus hannai was evaluated using four different statistical algorithms (geNorm, NormFinder, BestKeeper and comparative ΔCT method). Different algorithms identified different genes as the best candidates, and geometric mean-based final ranking from the most to the least stable expression was as follow: RPL5, RPL4, RPS18, RPL8, RPL7, UBE2, RPL7A, GAPDH, RPL36, PPIB, EF1A, ACTB and B-TU. The findings were further validated via relative quantification of metallothionein (MT) transcripts using the stable and unstable reference genes, and expression levels of MT were greatly influenced according to the choice of reference genes. In overall, our data suggest that RPL5 and RPS18, either singly or in combination, are appropriate for normalizing gene expression in developmental samples of this abalone species, whereas ACTB, B-TU and EF1A are less stable and not recommended. In addition, our findings propose that standard deviations in geometric ranking as well as geometric mean itself should also be taken into account for the final selection of reference gene(s). This study could be a useful basis to facilitate the generation of accurate and reliable RT-qPCR data with developmental samples in this abalone species.

• Journal of the Korean Orthopaedic Association
• /
• v.55 no.5
• /
• pp.411-417
• /
• 2020

Purpose: This paper reports the short-term clinical and radiological results of unilateral biportal endoscopic decompression (UBE) to prove its efficacy. Materials and Methods: Twenty patients who received unilateral biportal endoscopic far-lateral decompression (UBEFLD) were analyzed statistically using the visual analogue scale (VAS), modified Macnab criteria and Oswestry Disability Index (ODI) clinically. Radiologically, their intervertebral angle (IVA), percentage slip, disc height index (DHI) and foraminal height index (FHI) were analyzed pre- and postoperatively. Results: The VAS scores were 6.20 preoperatively, which improved to 2.05, 1.75 and 1.45 at postoperative one month, three months and one year, respectively (p<0.001). The modified macnab criteria in both the good or excellent category was 70.0%, 80.0% and 85.0% at postoperative one month, three months and one year, respectively (p=0.034). The ODI improved from 59.8% preoperatively to 35.8%, 33.2%, and 17.1% at postoperative one month, three months, and one year, respectively (p<0.001). The IVA was increased 0.40±0.88 after a surgery (p=0.057). Percentage slip was increased 0.19% after surgery (p=0.134). The DHI changed from 0.49 preoperatively to 0.62 postoperatively (p=0.359), and the FHI changed from 0.71 preoperatively to 0.79 postoperatively (p<0.001). Conclusion: UBEFLD displayed satisfactory results. Such a result highlights the potential of UBEFLD as an excellent alternative to spinal fusion or microscopic surgery.

• The Korean Journal of Physiology and Pharmacology
• /
• v.21 no.6
• /
• pp.625-632
• /
• 2017

Familial Parkinson's disease (PD) has been linked to point mutations and duplication of the ${\alpha}$-synuclein (${\alpha}$-syn) gene. Mutant ${\alpha}$-syn expression increases the vulnerability of neurons to exogenous insults. In this study, we developed a new PD model in the transgenic mice expressing mutant hemizygous (hemi) or homozygous (homo) A53T ${\alpha}$-synuclein (${\alpha}$-syn Tg) and their wildtype (WT) littermates by treatment with sub-toxic (10 mg/kg, i.p., daily for 5 days) or toxic (30 mg/kg, i.p., daily for 5 days) dose of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Tyrosine hydroxylase and Bcl-2 levels were reduced in the ${\alpha}$-syn Tg but not WT mice by sub-toxic MPTP injection. In the adhesive removal test, time to remove paper was significantly increased only in the homo ${\alpha}$-syn Tg mice. In the challenging beam test, the hemi and homo ${\alpha}$-syn Tg mice spent significantly longer time to traverse as compared to that of WT group. In order to find out responsible proteins related with vulnerability of mutant ${\alpha}$-syn expressed neurons, DJ-1 and ubiquitin enzyme expressions were examined. In the SN, DJ-1 and ubiquitin conjugating enzyme, UBE2N, levels were significantly decreased in the ${\alpha}$-syn Tg mice. Moreover, A53T ${\alpha}$-syn overexpression decreased DJ-1 expression in SH-SY5Y cells. These findings suggest that the vulnerability to oxidative injury such as MPTP of A53T ${\alpha}$-syn mice can be explained by downregulation of DJ-1.