• The korean journal of orthodontics
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• v.39 no.2
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• pp.105-111
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• 2009

Objective: To estimate the effects of bracket material type on enamel decalcification during orthodontic treatment, this study analyzed the adhesion level of mutans streptococci (MS) to orthodontic bracket materials in vivo. Methods: Three different types of orthodontic bracket materials were used: stainless steel, monocrystalline sapphire, and polycrystalline alumina. A balanced complete block design was used to exclude the effect of positional variation of bracket materials in the oral cavity. Three types of plastic individual trays were made and one subject placed the tray in the mouth for 12 hours. Then, the attached bacteria were isolated and incubated on a mitis salivarius media containing bacitracin for 48 hours. Finally, the number of colony forming units of MS was counted. The experiments were independently performed 5 times with each of the 3 trays, resulting in a total of 15 times. Mixed model ANOVA was used to compare the adhesion amount of MS. Results: There was no difference in colony forming units among the bracket materials irrespective of jaw and tooth position. Conclusions: This study suggested that the result of quantitative analysis of MS adhesion to various orthodontic bracket materials in vivo may differ from that of the condition in vitro.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.431-437
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• 2015

Recently, assessment of nitrogen balance has been required for environmental agriculture. Nutrient management using organic matters in farmlands has been strongly required as a means of extending resource-cycling agriculture and reduction of nitrogen balance. Organic matters-derived nutrients and soil-available nitrogen should be necessarily considered to manage nutrient balance in soil-plant system. In this study, we reviewed the amount of N supply according to types of organic matter such as livestock compost and green manure in arable land. In case of applied livestock compost in soil, nitrogen mineralization was influenced by nitrogen amount of livestock manure and mixed materials. And nitrogen mineralization of green manure in arable land was influenced by types of crop and return period of green manure because of change of C/N ratio. Also, nitrogen supply by organic matter in arable land can be changed by environmental factors such as temperature, moisture in soil. Therefore, nitrogen supply according to C/N ratio of organic matter and analysis method for estimation of soil nitrogen supply availability should be evaluated to set up the nutrient management model.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.4
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• pp.457-468
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• 2007

Statements of problem: The fracture of acrylic resin dentures remains an unsolved problem. Therefore, many investigations have been performed and various approaches to strengthening acrylic resin, for example, the reinforcement of heat-cured acrylic resin using glass fibers, have been suggested over the years. Silane is important for bonding between glass fiber and resin. Purpose: The aim of the present study was to investigate the effect of various silane on the strength of PMMA resin and roughness of resin-glass fiber complex after abrasion test. Material and methods: 3mm glass fiber (Chopped strand, Hankuk fiber Co., Milyang, Korea) was treated with 3 kinds of silane (MPS, EPS, APS) (Sila-ace, Chisso chemical, Tokyo, Japan) and mixed with PMMA resin(Vertex RS, Vertex Dental B.V., Zeist, Netherlands). Transverse strength and Young's modulus was measured using Instron (Instron model 4466, Instron, Massachusetts, USA). After abrasion test (The 858 Mini Bionix II Test System, MTS System Co., Minnesota, USA) surface roughness was evaluated using tester (Form Talysurf plus, Taylor Hopson Ltd., Leicester England). Examination of scanning electron microscope was also performed. Results: Within this study, the following conclusions were drawn. 1. Surface treatment of glass fiber with MPS and APS increased transverse strength of PMMA resin complex, but surface treatment with EPS decreased transverse strength of PMMA resin complex (p<0.05). 2. Silane treated glass fiber increased Young's modulus of PMMA resin complex compared to desized glass fiber (p<0.05). 3. Roughness increased after abrasion test in case of PMMA resin reinforced with desized glass fiber (p<0.05). 4. Roughness change was not observed after abrasion test in case of PMMA resin reinforced with silane treated glass fiber (p>0.05).

• Journal of Life Science
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• v.20 no.9
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• pp.1294-1298
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• 2010

White spot syndrome virus (WSSV) is one of the most virulent viral agents threatening the penaeid shrimp culture industry. This study was carried out to evaluate the susceptibility of the sand shrimp, Crangon affinis, to WSSV as an alternative experimental model. WSSV caused 100% mortality in C. affinis within 7 days after experimental infection by immersion. Based on challenge studies, it was confirmed that C. affinis could be a potential host in WSSV transmission. Also, the neutralization of WSSV was carried out using an antiserum raised against recombinant envelop protein rVP466 to evaluate the WSSV infection mechanism. A constant amount of WSSV (at $1{\times}10^4$ diluted stocks) was incubated with various amounts of antiserum and then mixed to 20 l reservoir for the immersion challenge of C. affinis for neutralization. At 5 days post challenge, the shrimp in the positive control immersed in the immersion reservoir containing WSSV stock showed 100% mortality. The shrimps challenged with the 3 different mixtures of WSSV and rVP466 antiserum (1:0.1, 1:0.5 and 1:1) showed 100%, 68.8% and 68.8% mortality at 14 days post challenge, respectively. These results indicated that the antiserum raised against rVP466 could block WSSV infection in C. affinis. Therefore, this study confirmed that C. affinis can be naturally infected by WSSV as another potential host and that C. affinis can be used as an alternative experimental animal instead of penaeid shrimps.

• Journal of Life Science
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• v.30 no.8
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• pp.713-721
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• 2020

Adipogenesis as a model system is needed to understand the molecular mechanisms of human adipocyte biology and the pathogenesis of obesity, diabetes, and other metabolic syndromes. Many relevant studies have been conducted with a focus on gene expression regulation and intracellular signaling relating to Peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), which are master adipogenic transcription factors. However, epigenome regulation of adipogenesis by epigenomic modifiers or histone mutations is not fully understood. Histone methylation is one of the major epigenetic modifications on gene expression in mammals, and histone H3 lysine methylation (H3Kme) in particular implicates cell differentiation during various tissue and organ development. During adipogenesis, cell type-specific enhancers are marked by histone H3K4me1 with the active enhancer mark H3K27ac. Mixed-lineage leukemia 4 (MLL4) is a major H3K4 mono-methyltransferase on the adipogenic enhancers of PPARγ and C/EBPα loci. Thus, MLL4 is an important epigenomic modifier for adipogenesis. The repressive mark H3K27me3 is mediated by the enzymatic subunit Enhancer zeste homolog 2 (EZH2) of the polycomb repressive complex 2. EZH2-mediated H3K27 tri-methylation on the Wnt gene increases adipogenesis because WNT signaling is a negative regulator of adipogenesis. This review summarizes current knowledge about the epigenomic regulation of adipogenesis by histone H3 lysine methylation which fundamentally regulates gene expression.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.5
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• pp.499-503
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• 1995

The performance records of 410 Holstein Friesian crossbred cows belonging to seven genetic groups (Fl, 3/4, 1/4, 5/8, 3/8, triple cross and miscellaneous cross) maintained at Livestock Production Research Institute, Bahadurnagar, Okara were analyzed for various parameters of lifetime traits. For the analysis 2 data sets were made. Data set I included all the cows disposed off from the herd which have completed at least one lactation while for data set II performance traits for only first five lactations were considered. The data was analyzed by Mixed Model Least squares and Maximum Likelihood computer programme PC-I version. The least squares means ${\times}$ standard errors for data set I (periods are in days and milk yield is in litres) were $994.5{\pm}15.5$, $1,877.0{\pm}70.9$, $1,651.9{\pm}19.3$, $2,533.7{\pm}36.5$, $3,530.0{\pm}40.5$, $15,785.2{\pm}320.0$, $8.46{\pm}0.19$, $5.66{\pm}0.16$ and $3.79{\pm}0.08$, respectively for age at first calving (APC), Ist lactation milk yield (FLMY), productive life (PL), herd life (HL), total life (TL), lifetime milk yield (LTMY), milk yield per day of productive life (MY/PL), milk yield per day of herd life (MY/HL) and milk yield per day of total life (MY/TL). For data set II these values were $1,004.2{\pm}21.2$, $2,220.5{\pm}113.1$, $1,429.1{\pm}40.8$, $2,302.1{\pm}73.3$, $3,307.2{\pm}77.3$, $13,189.7{\pm}667.4$, $9.10{\pm}0.34$, $5.66{\pm}0.25$ and $4.02{\pm}0.18$ in the same order. For data set I the effect of year of first calving was significant for AFC, FLMY, PL, HL, LTMY and MY/PL. The season of Ist calving was significant only for MY/PL. The effect of genetic group was significant for AFC, FLMY, MY/PL and MY/TL while the effect of parity was significant for all the traits. For data set II the effect of year of Ist calving was significant only for AFC, FLMY and PL while the season of Ist calving was significant for FLMY and PL while the effect of genetic groups was significant for MY/HL only. The lifetime production performance is in general close to the various estimates reported in the literature.

• Journal of the Korean Chemical Society
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• v.37 no.11
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• pp.923-928
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• 1993

The series of solid solutions in the $Sr_{1+x}Ho_{1-x}FeO_{4-y}$ (x = 0.00, 0.25, 0.50, 0.75 and 1.00) systems with $K_2NiF_4$ type structure have been prepared at 1550$^{\circ}$C under an atmospheric air pressure. The X-ray powder diffraction spectra of these samples assign that the crystallographic phases are tetragonal system over the whole x range. The lattice volume was increased with increasing the substitution amount of the $Sr^{2+}$ ion. The mole ratio of the $Fe^{4+}$ ion to total iron ions or ${\tau}$ value has been determined by Mohr salt titration of the sample and then the y value was calculated from x and ${\tau}$ values. The ${\tau}$ and y values have been increased with x values. The nonstoichiometric chemical formula are formulated from the general formula of $Sr_{1+x}Ho_{1-x}Fe^3_{1-}\;^+_{\tau}Fe_{\tau}^{4+}O_{4-y}$ replaced by x,${\tau}$ and y values. Mossbauer spectra show the mixed valence state and coordination state of $Fe^{3+}\;and\;Fe^{4+}$ ions. It is found out that the magnetic property of the samples is paramagnetic at room temperature. Electrical conductivity varied within the semiconductivity range of 1.0 to 1 ${\times}\;10^{-9}{\Omega}^{-1}cm^{-1}$. Activation energy of the electrical conductivity was decreased with the $\tau$ value. The conduction mechanism should be explained by the hopping model of the conduction electrons between the valence states of $Fe^{3+}\;and\;Fe^{4+}$ ions.

• Korean Journal of Crystallography
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• v.12 no.4
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• pp.197-206
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• 2001

A stoichiometric mixture of evaporating materials for AgInS₂ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films. AgInS₂ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy(HWE)system. The source and substrate temperatures were 680℃ and 410℃, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility of AgInS₂ single crystal thin film mea-sured from Hall effect by van der Pauw method are 9.35×10/sup 16/㎤ and 294㎠/V·s at 293K respectively. The temperature dependence of the energy band gap of the AgInS₂ obtained from the absorption spectra was well described by the Varshni's relation , E/sub g/(T)=2.1365eV-(9.89×10/sup-3/eV/K/)T²(T+2930K). The crystal field and the spin-orbit splitting energies for the valence band of the AgInS₂ have been estimated to be 0.1541eV and 0.0129 eV, respectively, by means of the photocur-rent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the Δso definitely exists in the Γ/sub 5/ states of the valence band of the AgInS₂ /GaAs epilayer. The three photo-current peaks ovserved at 10K are ascribed to the A₁-, B-₁and C₁-exction peaks for n=1.

• Management & Information Systems Review
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• v.34 no.2
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• pp.151-169
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• 2015

Social enterprises that are solving pressing global issues and providing services such as micro-finance, affordable housing, appropriate technology and education for the 'bottom of the pyramid' as well as cultural and community-related businesses that improve the 'quality of life' within a society are the target of impact investments. Among them, a capital financing is one of the most important factor in founding and fostering of social enterprise. However, the capital market for social enterprises in South Korea are not yet sufficiently developed. The Britain and U.S.A. attempted to solve the social problem by the introduction of the social innovation credit model, for example, social impact bonds(SIB), Big Society Capital, DBLIF, and ACCION International, which are considered as an innovative new financing instrument for social program. Instruments are being attempted for the first time in Britain and America. This study have two purposes. The first purpose is abstracting the institutional mechanism for introduction of impact investment such as SIB and DBLIF case in Britain and U.S.A.. Second, analyzing type and mix of policy instrument on impact investment from the perspective of policy instrument.

• Journal of Ginseng Research
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• v.40 no.2
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• pp.185-195
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• 2016

Background: To investigate the effect of pectinase-treated Panax ginseng (GINST) in cellular and male subfertility animal models. Methods: Hydrogen peroxide ($H_2O_2$)-induced mouse spermatocyte GC-2spd cells were used as an in vitro model. Cell viability was measured using MTT assay. For the in vivo study, GINST (200 mg/kg) mixed with a regular pellet diet was administered orally for 4 mo, and the changes in the mRNA and protein expression level of antioxidative and spermatogenic genes in young and aged control rats were compared using real-time reverse transcription polymerase chain reaction and western blotting. Results: GINST treatment ($50{\mu}g/mL$, $100{\mu}g/mL$, and $200{\mu}g/mL$) significantly (p < 0.05) inhibited the $H_2O_2$-induced ($200{\mu}M$) cytotoxicity in GC-2spd cells. Furthermore, GINST ($50{\mu}g/mL$ and $100{\mu}g/mL$) significantly (p < 0.05) ameliorated the $H_2O_2$-induced decrease in the expression level of antioxidant enzymes (peroxiredoxin 3 and 4, glutathione S-transferase m5, and glutathione peroxidase 4), spermatogenesis-related protein such as inhibin-${\alpha}$, and specific sex hormone receptors (androgen receptor, luteinizing hormone receptor, and follicle-stimulating hormone receptor) in GC-2spd cells. Similarly, the altered expression level of the above mentioned genes and of spermatogenesis-related nectin-2 and cAMP response element-binding protein in aged rat testes was ameliorated with GINST (200 mg/kg) treatment. Taken together, GINST attenuated $H_2O_2$-induced oxidative stress in GC-2 cells and modulated the expression of antioxidant-related genes and of spermatogenic-related proteins and sex hormone receptors in aged rats. Conclusion: GINST may be a potential natural agent for the protection against or treatment of oxidative stress-induced male subfertility and aging-induced male subfertility.