• The Journal of Advanced Prosthodontics
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• v.9 no.5
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• pp.394-401
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• 2017

PURPOSE. The purpose of this study was to compare the optical properties of pre-colored dental monolithic zirconia ceramics of various thicknesses sintered in a microwave and those in a conventional furnace. MATERIALS AND METHODS. A2-shade of pre-colored monolithic zirconia ceramic specimens ($22.0mm{\times}22.0mm$) in 3 thickness groups of 0.5, 1.0, and 1.5 mm were divided into 2 subgroups according to the sintering methods (n=9): microwave and conventional sintering. A spectrophotometer was used to obtain CIELab color coordinates, and translucency parameters and CIEDE2000 color differences (${\Delta}E_{00}$) were measured. The relative amount of monoclinic phase ($X_m$) was estimated with x-ray diffraction. The surface topography was analyzed by atomic force microscope and scanning electron microscope. Statistical analyses were conducted with two-way ANOVA (${\alpha}=.05$). RESULTS. There were small interaction effects on CIE $L^*$, $a^*$, and TP between sintering method and thickness (P<.001): $L^*$ (partial eta squared ${{\eta}_p}^2=0.115$), $a^*$ (${{\eta}_p}^2=0.136$), and TP (${{\eta}_p}^2=0.206$), although higher $b^*$ values were noted for microwave sintering regardless of thickness. Color differences between two sintering methods ranged from 0.52 to 0.96 ${\Delta}E_{00}$ units. The $X_m$ values ranged from 7.03% to 9.89% for conventional sintering, and from 7.31% to 9.17% for microwave sintering. The microwave-sintered specimen demonstrated a smoother surface and a more uniform grain structure compared to the conventionally-sintered specimen. CONCLUSION. With reduced processing time, microwave-sintered pre-colored dental monolithic zirconia ceramics can exhibit similar color perception and translucency to those by conventional sintering.

• Carbon letters
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• v.24
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• pp.90-96
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• 2017

We demonstrated the sensitivity of optically active single-walled carbon nanotubes (SWCNTs) with a diameter below 1 nm that were homogeneously dispersed in cement composites under a mechanical load. Deoxyribonucleic acid (DNA) was selected as the dispersing agent to achieve a homogeneous dispersion of SWCNTs in an aqueous solution, and the dispersion state of the SWCNTs were characterized using various optical tools. It was found that the addition of a large amount of DNA prohibited the structural evolution of calcium hydroxide and calcium silicate hydrate. Based on the in-situ Raman and X-ray diffraction studies, it was evident that hydrophilic functional groups within the DNA strongly retarded the hydration reaction. The optimum amount of DNA with respect to the cement was found to be 0.05 wt%. The strong Raman signals coming from the SWCNTs entrapped in the cement composites enabled us to understand their dispersion state within the cement as well as their interfacial interaction. The G and G' bands of the SWCNTs sensitively varied under mechanical compression. Our results indicate that an extremely small amount of SWCNTs can be used as an optical strain sensor if they are homogeneously dispersed within cement composites.

• Korea-Australia Rheology Journal
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• v.14 no.4
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• pp.189-201
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• 2002

The interaction between hydrophobically modified hydroxyethyl cellulose (hmHEC), containing approximately 1 wt% side-alkyl chains of $C_{16}$, and an anionic sodium dodecyl sulphate (SDS) surfactant was investigated. For a semi-dilute solution of 0.5 wt% hmHEC, the previously observed behaviour of a maximum in solution viscosity at intermediate SDS concentrations, followed by a drop at higher SDS concentrations, until above the cmc of surfactant when the solution resembles that of the unsubstituted polymer, was confirmed. Additionally, a two-phase region containing a hydrogel phase and a water-like supernatant was found at low SDS concentrations up to 0.2 wt%, a concentration which is akin to the critical association concentration, cac, of SDS in the presence of hmHEC. Above this concentration, SDS molecules bind strongly to form mixed micellar aggregates with the polymer alkyl side-chains, thus strengthening the network junctions, resulting in the observed increase in viscosity and elastic modulus of the solution. The shear behaviour of this polymer-surfactant complex during steady and step stress experiments was examined In great detail. Between SDS concentrations of 0.2 and 0.25 wt%, the shear viscosity of the hmHEC-polymer complex network undergoes shear-induced thickening, followed by a two-stage shear-induced fracture or break-up of the network. The thickening is thought to be due to structural rearrangement, causing the network of flexible polymers to expand, enabling some polymer hydrophobic groups to be converted from intra- to inter-chain associations. At higher applied stress, a partial local break-up of the network occurs, while at even higher stress, above the critical or network yield stress, a complete fracture of the network into small microgel-like units, Is believed to occur. This second network rupture is progressive with time of shear and no steady state in viscosity was observed even after 300 s. The structure which was reformed after the cessation of shear is found to be significantly different from the original state.

• Journal of Preventive Medicine and Public Health
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• v.50 no.6
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• pp.393-400
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• 2017

Objectives: To relieve the financial burden faced by households, the Korean National Health Insurance (NHI) system introduced a "copayment ceiling," which evolved into a differential ceiling in 2009, with the copayment ceiling depending on patients' income. This study aimed to examine the effect of the differential copayment ceiling on financial protection and healthcare utilization, particularly focusing on whether its effects varied across different income groups. Methods: This study obtained data from the Korea Health Panel. The number of households included in the analysis was 6555 in 2008, 5859 in 2009, 5539 in 2010, and 5372 in 2011. To assess the effects of the differential copayment ceiling on utilization, out-of-pocket (OOP) payments, and catastrophic payments, various random-effects models were applied. Utilization was measured as treatment days, while catastrophic payments were defined as OOP payments exceeding 10% of household income. Among the right-hand side variables were the interaction terms of the new policy with income levels, as well as a set of household characteristics. Results: The differential copayment ceiling contributed to increased utilization regardless of income levels both in all patients and in cancer patients. However, the new policy did not seem to reduce significantly the incidence of catastrophic payments among cancer patients, and even increased the incidence among all patients. Conclusions: The limited effect of the differential ceiling can be attributed to a high proportion of direct payments for services not covered by the NHI, as well as the relatively small number of households benefiting from the differential ceilings; these considerations warrant a better policy design.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.888-893
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• 2000

The present study was conducted to evaluate heterosis effects of body weight and jumping height for successive generations of rotational crossing using two subspecies of mice which are very different in body weight and in genetic relationship from each other. Domesticated laboratory mouse $CF_{{\sharp}1}$ (C) and Yonakuni wild mouse (Y) were used as materials. Two groups of rotational crossing was made according to the parent used at the beginning of crosses, C male$\times$Y female and Y male$\times$C female. These crosses were done to produce the first ($G_1$ and $G_1{^{\prime}}$), second ($G_2$ and $G_2{^{\prime}}$) and third generations ($G_3$ and $G_3{^{\prime}}$) with sire used was alternated. Individual body weights were weighed at 1 (wk1), 3 (wk3), 6 (wk6) and 10 weeks of age (wk10) and jumping heights were measured at six weeks of age (wk6). Only the first litter used. For body weight, results of this study showed that genetic group effects were significant (p<0.01) source of variation at all ages studied. Sex effects were significant (p<0.01) at wk3, wk6 and wk10, but not at wk1. Significant interaction effects (p<0.01) between genetic group and sex were found at wk6 and wk10. The C mice with large maternal effects produced heavier offspring body weight and crosses using sire of this subspecies maintained heavy weight compared to wild Y mouse sire that has small body size. Heterosis tended to exist at the rotational crossing started from Y male C female. For jumping height, effects of genetic group and sex were significant, sire and dam effects (heterosis) exhibited from the first to third generations, and no maternal effects were observed.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.543-551
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• 2002

Nitric oxide (NO) is a small molecule (mol. wt. 30 Da) and oxidative free radical. It is uncharged and can therefore diffuse freely within and between cells across membrane. Such characteristics make it a biologically important messenger in physiologic processes such as neurotransmission and the control of vascular tone. NO is also highly toxic and is known to acts as a mediator of cytotoxicity during host defense. NO is synthesized by nitric oxide synthase (NOS) through L-arginine/nitric oxide pathway which is a dioxygenation process. NO synthesis involves several participants, three co-substrates, five electrons, five co-factors and two prosthetic groups. Under normal condition, low levels of NO are synthesized by type I and III NOS for a short period of time and mediates many physiologic processes. Under condition of oxidant stress, high levels of NO are synthesized by type II NOS and inhibits a variety of metabolic processes and can also cause direct damage to DNA. Such interaction result in cytostasis, energy depletion and ultimately cell death. NO has the potential to interact with a variety of intercellular targets producing diverse array of metabolic effects. It is known that NO is involved in hemodynamic regulation, neurogenic inflammation, re-innervation, management of dentin hypersensitivity on teeth. Under basal condition of pulpal blood flow, NO provides constant vasodilator tone acting against sympathetic vasoconstriction. Substance P, a well known vasodilator, was reported to be mediated partly by NO, while calcitonin-gene related peptide has provided no evidence of its relation with NO. This review describes the roles of NO in dental pulp in addition to the known general roles of it.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.5
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• pp.259-271
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• 2019

The purpose of this study is to examine the potential of flip learning in Korea and to explore the possibilities of university English education. To this end, participants are sought for classes wherein general English class is taught and the researcher is in charge of teaching. 25 students of media-English class is chosen for the study. Instruments for the study include class evaluation and feedbacks, mid-term and final exams, group performative evaluation, on-line class views and participations. The findings of the study are: As students progress in flipped learning classes, their exam results significantly improved, and their performative evaluation results also improved significant across different groups. The effects are more eminent among higher levels of students, but students with mid and low level of English still improved significantly once they engage themselves in preview activity on a regular basis and self-directedly.

• Parasites, Hosts and Diseases
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• v.62 no.2
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• pp.243-250
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• 2024

We investigated organ specific Toxocara canis larval migration in mice infected with T. canis larvae. We observed the worm burden and systemic immune responses. Three groups of BALB/c mice (n=5 each) were orally administered 1,000 T. canis 2nd stage larvae to induce larva migrans. Mice were sacrificed at 1, 3, and 5 weeks post-infection. Liver, lung, brain, and eye tissues were collected. Tissue from 2 mice per group was digested for larval count, while the remaining 3 mice underwent histological analysis. Blood hematology and serology were evaluated and compared to that in a control uninfected group (n=5) to assess the immune response. Cytokine levels in bronchoalveolar lavage (BAL) fluid were also analyzed. We found that, 1 week post-infection, the mean parasite load in the liver (72±7.1), brain (31±4.2), lungs (20±5.7), and eyes (2±0) peaked and stayed constant until the 3 weeks. By 5-week post-infection, the worm burden in the liver and lungs significantly decreased to 10±4.2 and 9±5.7, respectively, while they remained relatively stable in the brain and eyes (18±4.2 and 1±0, respectively). Interestingly, ocular larvae resided in all retinal layers, without notable inflammation in outer retina. Mice infected with T. canis exhibited elevated levels of neutrophils, monocytes, eosinophils, and immunoglobulin E. At 5 weeks post-infection, interleukin (IL)-5 and IL-13 levels were elevated in BAL fluid. Whereas IL-4, IL-10, IL-17, and interferon-γ levels in BAL fluid were similar to that in controls. Our findings demonstrate that a small portion of T. canis larvae migrate to the eyes and brain within the first week of infection. Minimal tissue inflammation was observed, probably due to increase of anti-inflammatory cytokines. This study contributes to our understanding of the histological and immunological responses to T. canis infection in mice, which may have implications to further understand human toxocariasis.

• Journal of The Korean Association For Science Education
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• v.37 no.1
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• pp.63-75
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• 2017

The purpose of this study is to explore the effect of responsive teaching on students' productive argumentation practice. The participating students predicted the results of an activity to measure in which location on the body (the head, spine, or back of the hand) they would feel a cellphone's vibrations faster. They then engaged in the activity and built an argument to justify it. We interviewed the teacher to understand her thoughts regarding what was expected in the class. We also recorded and transcribed the class and the interview, for use in the analysis of the students' epistemological framing and the teacher's responsive practice in small group argumentation. We discovered that the teacher intervened in the groups with questions that elicited students' thoughts as starting points for her responsive practice. Her eliciting questions led the students to talk about their ideas, supporting their engagement in the argumentation. The teacher's understanding of the argumentation lesson and her behavior to understand the students' ideas reflected her productive framing, which led her to elicit students' ideas and to support their active interaction during the small-group argumentation. She presented rebuttals against students' ideas, engaging in the argumentation as another participant, not as an evaluator. This supported the equality of intellectual authority in the group and showed students how to engage in the argumentation, supporting students' productive framing. As a result of these responsive teaching practices, the students shifted their epistemological framing, resulting in productive argumentation practice. The results of this study will contribute to developing teachers' responsive teaching strategies to support students' productive framing in science classrooms.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.585-591
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• 2019

Objective: This study investigated carcass characteristics and meat quality of purebred Pakchong 5, crossbred pigs sired by Pakchong 5, and crossbred pigs sired by Duroc. Methods: Forty-eight pigs (average body weight of 22.25 kg) were composed of three groups as purebred Pakchong 5 (PP), Large $White{\times}Landrace$ pigs sired by Pakchong 5 (LWLRP), and Large $White{\times}Landrace$ pigs sired by Duroc (LWLRD). Each group consisted of eight gilts and eight barrows. At 109-day-raising period, pigs were slaughtered, and carcass characteristics were evaluated. Longissimus thoracis (LT) muscles from left side of carcasses were evaluated for meat quality and chemical composition. Data were analyzed using general linear model procedure, where group, sex, and their interaction were included in the model. Results: The PP had greater carcass, total lean, and ham percentages than crossbred pigs (p<0.05). LWLRP had thicker backfat and more carcass fat percentage than LWLRD (p<0.05). There were no differences (p>0.05) on cutting percentages from tender loin, loin, boston butt, and picnic shoulder among groups. The PP and LWLRP had larger loin eye area (LEA) than LWLRD (p<0.05). Gilts had more loin percentage and lower $L^*$ value than barrows (p<0.05). No meat color parameters ($L^*$, $a^*$, and $b^*$) were affected by groups (p>0.05). PP and LWLRP had larger muscle fiber diameters than LWLRD (p<0.05). However, water holding capacity, Warner-Bratzler shear force values, and chemical composition of LT were not affected by group or sex (p>0.05). Conclusion: Pakchong 5 purebred has good carcass and lean percentages. Compared to Duroc crossbred pigs, Pakchong 5 crossbreds have similar carcass and lean percentages, larger LEA, and slightly more carcass fat, with comparable meat quality and chemical composition. Pakchong 5 boars are more affordable for very small- to medium-scale pig producers.