• Bulletin of the Korean Mathematical Society
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• v.56 no.4
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• pp.1059-1075
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• 2019

Let G be a graph with no isolated vertex. A total dominating set, abbreviated TDS of G is a subset S of vertices of G such that every vertex of G is adjacent to a vertex in S. The total domination number of G is the minimum cardinality of a TDS of G. In this paper, we study the total domination number of central graphs. Indeed, we obtain some tight bounds for the total domination number of a central graph C(G) in terms of some invariants of the graph G. Also we characterize the total domination number of the central graph of some families of graphs such as path graphs, cycle graphs, wheel graphs, complete graphs and complete multipartite graphs, explicitly. Moreover, some Nordhaus-Gaddum-like relations are presented for the total domination number of central graphs.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.425-434
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• 2020

Background: Viral infection outbreaks are emerging public health concerns. They often exhibit seasonal patterns that could be predicted by the application of big data and bioinformatic analyses. Purpose: The purpose of this study was to identify trends in diarrhea-causing viruses such as rotavirus (Gr.A), norovirus G-I, and norovirus G-II in Cheonan, Korea. The identified related factors of diarrhea-causing viruses may be used to predict their trend and prevent their infections. Method: A retrospective analysis of 4,009 fecal samples from June 2010 to December 2019 was carried out at Dankook University Hospital in Cheonan. Reverse transcription-PCR (RT-PCR) was employed to identify virus strains. Information about seasonal patterns of infection was extracted and compared with local weather data. Results: Out of the 4,009 fecal samples tested using multiplex RT-PCR (mRT-PCR), 985 were positive for infection with Gr.A, G-I, and G-II. Out of these 985 cases, 95.3% (n = 939) were under 10 years of age. Gr.A, G-I, and G-II showed high infection rates in patients under 10 years of age. Student's t-test showed a significant correlation between the detection rate of Gr.A and the relative humidity. The detection rate of G-II significantly correlated with wind-chill temperature. Conclusion: Climate factors differentially modulate rotavirus and norovirus infection patterns. These observations provide novel insights into the seasonal impact on the pathogenesis of Gr.A, G-I, and G-II.

• Human Ecology Research
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• v.57 no.1
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• pp.109-125
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• 2019

Few studies have utilized observational methods in the field of couple research even though using self-report questionnaires is prone to the subjective biases of the reporter. This study validates the Marital Interaction Coding System-Global (MICS-G), a global version of the well-established microanalytic observational coding system, Marital Interaction Coding System (MICS). Participants in the study consisted of 30 married couples with varied levels of marital adjustment who visited one of the Healthy Family and Multicultural Family Support Centers in Seoul, either for couple therapy or the "Marriage Checkup"program. Ten-minute problem-solving discussions were rated by two undergraduate student raters who were trained for 10 hours. Interobserver agreement based on percentage agreement and intraclass correlation coefficients showed a high level of agreement between raters in establishing interrater reliability. Convergent validity was established by: correlations among marital adjustment, psychological aggression, mental health, and MICS-G categories of conflicts, validation, invalidation, facilitation, and withdrawal. MICS-G categories also were successful in discriminating between distressed and nondistressed couples, which provides evidence of discriminant validity for MICS-G. This study showed that MICS-G is a promising method for researchers to observe couple interactions in a more cost-effective way. Methodological issues and practical applications are also discussed.

• Journal of the Korean Ceramic Society
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• v.56 no.3
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• pp.284-290
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• 2019

Ternary MoS₂/graphene (G)-TiO₂ photocatalysts were prepared by a simple hydrothermal method. The morphology, phase structure, band gap, and catalytic properties of the prepared samples were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, UV-vis spectrophotometry, and Brunauer-Emmett-Teller surface area measurement. The H₂ production efficiency of the prepared catalysts was tested in methanol-water mixture under visible light. MoS₂/G-TiO₂ exhibited the highest activity for photocatalytic H₂ production. For 5 wt.% and 1 wt.% MoS₂ and graphene (5MT-1G), the production rate of H₂ was as high as 1989 µmol^-1h^-1. The catalyst 5MT-1G showed H₂ production activity that was ~ 11.3, 5.6, and 4.1 times higher than those of pure TiO₂, 1GT, and 5MT, respectively. The unique structure and morphology of the MoS₂/G-TiO₂ photocatalyst contributed to its improved hydrogen production efficiency under visible light.

• Journal of Dairy Science and Biotechnology
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• v.37 no.2
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• pp.136-153
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• 2019

The present study aimed to investigate the effects of skin care foods on the synthesis of pro-collagen type I C peptide and suppression of matrix metalloproteinase (MMP)-1 secretion through an in vitro study using fibroblasts (Hs68 cells) and keratinocytes (HaCaT cells). Among the three skin care foods developed in this study, three beans cookie and avocado yoghurt influenced the production of pro-collagen type I C peptide and suppressed MMP-1 secretion; however, tiger nut Galsu drink did not exhibit these effects. All skin care foods, including three beans cookie and plain yoghurt ($50{\mu}g/mL$, p<0.001) influenced the suppression of MMP-1 in addition to other commercially available breast milk production support foods examined, such as Heath Heather ($50{\mu}g/mL$, p<0.001), Happy Mama ($50{\mu}g/mL$, p<0.01), BioLys ($50{\mu}g/mL$, p<0.001), Enfamama ($25{\mu}g/mL$, p<0.0001), and Pregnagen ($25{\mu}g/mL$, p<0.001). Avocado fruit yoghurt ($25{\mu}g/mL$, p<0.05), avocado fruit jam yoghurt ($50{\mu}g/mL$, p<0.01), Enfamama ($100{\mu}g/mL$, p<0.05), and Pregnagen ($100{\mu}g/mL$, p<0.05) influenced the production of pro-collagen type I C peptide and suppressed MMP-1 secretion. This result indicates that only avocado jam yoghurt significantly influenced both the prevention of skin keratinization and acceleration of recovery of skin fibrous structure. Therefore, avocado is a favorable ingredient for nutrition-balanced dietary foods or an essential ingredient in products for revitalization of human skin.

• BMB Reports
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• v.43 no.4
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• pp.233-244
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• 2010

Parkinson's disease (PD) is the second most common neurodegenerative disease, and 5-10% of the PD cases are genetically inherited as familial PD (FPD). LRRK2 (leucine-rich repeat kinase 2) was first reported in 2004 as a gene corresponding to PARK8, an autosomal gene whose dominant mutations cause familial PD. LRRK2 contains both active kinase and GTPase domains as well as protein-protein interaction motifs such as LRR (leucine-rich repeat) and WD40. Most pathogenic LRRK2 mutations are located in either the GTPase or kinase domain, implying important roles for the enzymatic activities in PD pathogenic mechanisms. In comparison to other PD causative genes such as parkin and PINK1, LRRK2 exhibits two important features. One is that LRRK2's mutations (especially the G2019S mutation) were observed in sporadic as well as familial PD patients. Another is that, among the various PD-causing genes, pathological characteristics observed in patients carrying LRRK2 mutations are the most similar to patients with sporadic PD. Because of these two observations, LRRK2 has been intensively investigated for its pathogenic mechanism (s) and as a target gene for PD therapeutics. In this review, the general biochemical and molecular features of LRRK2, the recent results of LRRK2 studies and LRRK2's therapeutic potential as a PD target gene will be discussed.

• Animal Systematics, Evolution and Diversity
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• v.35 no.1
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• pp.1-5
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• 2019

The specimens of caddisflies previously recorded as Sortosa distincta (Walker, 1852), Rhyacophila uchidai Kobayashi, 1989, Rhyacophila jirisana Kobayashi, 1989, Crunobiodes koriaensis Kobayashi, 1989, and Ganonema odaenum Kobayashi, 1989 from South Korea were reexamined. Rhyacophila uchidai and R. jirisana are newly synonymized with R. retracta Martynov, 1914 and R. vicina Botosaneanu, 1970, respectively. We reconfirm two synonyms, C. koriaensis with Lepidostoma sinuatum (Martynov, 1935) and G. odaenum with Psilotreta locumtenens Botosaneanu, 1970, and a misidentification of Dolophilodes affinis Levanidova and Arefina, 1996 as S. distincta. Some specimens recorded as G. odaenum are identified as Psilotreta falcula Botosaneanu, 1970.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.139-147
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• 2019

Incorporation of CuO nanoparticles during the polymerization of aniline in the presence of ammonium peroxydisulphate as an oxidizing agent and sodium salt of dodecylbenzene sulphonic acid as dopant as well as surfactant yielded water soluble CuO-PANI composite. Comparison of recorded spectra like FTIR, XRD and SEM with reported one confirm the formation of the composite. Analysis by gravimetric method exposes that the synthesized composite is having resistivity against corrosion, with slight variation in efficiency on extending the time duration up to eight hours in strong acidic condition. OCP measurement, potentiodynamic polarization and EIS studies also confirms the suppression ability of composite against corrosion. Riskless working environment could be provided by the synthesized composite during industrial cleaning process.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.135-138
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• 2019

The aim of this study was to investigate the susceptibility of Mutans streptococci in both planktonic and biofilm states to erythrosine. S. mutans was cultured in brain-heart infusion (BHI) broth. Erythrosine was diluted in BHI broth and prepared at a concentration range of $0.02-10000{\mu}g/L$. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured using the microdilution method. After forming biofilms on 96-well plates, the minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were measured. S. mutans was susceptible to erythrosine in both planktonic and biofilm states. MIC and MBC values were both $19.5{\mu}g/L$ for the planktonic state, while MBIC and MBEC values were $313{\mu}g/L$ and $2500{\mu}g/L$, respectively, for the biofilm state. Erythrosine ($19.5{\mu}g/L$) exhibited a bactericidal effect on S. mutans (killing 99.9%) in the planktonic state. For biofilms, erythrosine inhibited biofilm growth and eradicated 99.9% of biofilm bacteria at higher concentrations than MIC and MBC. These MBIC and MBEC concentrations are much lower than known noxious doses, and the MIC, MBC, and MBIC values were even lower than clinical concentrations.

• Structural Engineering and Mechanics
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• v.69 no.4
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• pp.361-369
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• 2019

The determination of Paris' law parameters based on crack growth experiments is an important procedure of fatigue life assessment. However, it is a challenging task because it involves various sources of uncertainty. This paper proposes a novel probabilistic method, termed the S-N Paris law (SNPL) method, to quantify the uncertainties underlying the Paris' law parameters, by finding the best estimates of their statistical parameters from the S-N curve data using a Bayesian approach. Through a series of steps, the SNPL method determines the statistical parameters (e.g., mean and standard deviation) of the Paris' law parameters that will maximize the likelihood of observing the given S-N data. Because the SNPL method is based on a Bayesian approach, the prior statistical parameters can be updated when additional S-N test data are available. Thus, information on the Paris' law parameters can be obtained with greater reliability. The proposed method is tested by applying it to S-N curves of 40H steel and 20G steel, and the corresponding analysis results are in good agreement with the experimental observations.