• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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• pp.13-18
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• 2019

We determined the contents of 11 biogenic amines in 20 types of cabbage kimchi, 10 types of fish sauce, and 40 types of salted fish purchased from small- and medium-sized grocery stores in Gyeonggi-Do, Republic of Korea, from June to October 2017. The content of each of the biogenic amines in the various types of cabbage kimchi was slightly lower than that in detection amounts of each of the 10 types of biogenic amines and the values reported by Joe et al. The histamine content of all five types of anchovy sauce was lower than the limit set by the European Union (400 mg/kg), but that of three of the five types of sand lance sauce was higher. Analyzing the ratios of the contents of five highly toxic biogenic amines to those of the 11 biogenic amines yielded no quantitative correlation. The estimated daily intake of the five highly toxic biogenic amines in cabbage-kimchi and fermented fish was ${\leq}6mg$.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.343-353
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• 2018

Our previous research demonstrated the essential role of the xenB gene in stress response to RDX by using Pseudomonas sp. HK-6 xenB knockout. We have extended this work to examine the cellular responses and altered proteomic profiles of the HK-6 xenA knockout mutant under RDX stress. The xenA mutant degraded RDX about 2-fold more slowly and its growth and survival rates were several-fold lower than the wild-type HK-6 strain. SEM revealed more severe morphological damages on the surface of the xenA mutant cells under RDX stress. The wild-type cells expressed proportionally-increased two stress shock proteins, DnaK and GroEL from the initial incubation time point or the relatively low RDX concentrations, but slightly less expressed at prolonged incubation period or higher RDX. However the xenA mutant did not produced DnaK and GroEL as RDX concentrations were gradually increased. The wild-type cells well maintained transcription levels of dnaA and groEL under increased RDX stress while those in the xenA mutant were decreased and eventually disappeared. The altered proteome profiles of xenA mutant cells under RDX stress also observed so that the 27 down-regulated plus the 3 up-regulated expression proteins were detected in 2-DE PAGE. These all results indicated that the intact xenA gene is necessary for maintaining cell integrity under the xenobiotic stress as well as performing an efficient RDX degradation process.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.429-437
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• 2018

In this study, the mixed toxicity of heavy metals (Cu, Pb, Hg) and surfactants (SLS, ALS) was evaluated by using Vibrio fischeri and Daphnia magna. The sensitivity of ecotoxicity to heavy metals was sensitive to daphnia but the case of surfactants were more sensitive to Vibrio fischeri. Experimental results of Vibrio fischeri show that the toxicity value P(O) was lower than the predicted value P(E), and the antagonistic effect was observed when the heavy metal and the surfactant were mixed. It seems that SLS and ALS, which are anionic surfactants, have anionic form on the hydrophilic head, so that they have an antagonistic effect that they are bonded with heavy metal ion which is a cation type and the actual toxicity is lowered. In Daphnia magna, the results showed that antagonistic, additive and synergistic effects were in order as concentrations increased. As the concentration increases, Daphnia magna, which is highly sensitive to heavy metals, seems to have a synergistic effect with a rapid increase in mortality.

• The Korea Journal of Herbology
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• v.36 no.5
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• pp.15-27
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• 2021

Objectives : The processing of Pinelliae Tuber and Arisaematis Rhizoma is a crucial step to reduce the severe acrid irritation mainly due to the needle-like crystals (raphides). Ginger, alum and bile juice have been used as adjuvant materials for the processing. Methods : Bibliographic research on ancient processing and experimental processing was performed to investigate the toxicity reduction mechanisms of the processing with ginger, alum and bile juice. Results : Ginger has been a major adjuvant for the processing of Pinelliae Tuber, followed by alum and bile juice since Song (宋) and Myeong (明) dynasties, and Arisaematis Rhizoma has been mainly used as Damnamseong (膽南星). The raphides consisting of calcium oxalate, lectin, agglutinin and polysaccharides can induce acrid irritation and the inflammatory reactions. The lipophilic components in the ginger denatured the structure of raphides and 6-gingerol-contained ginger extract attenuated the inflammatory reaction. The calcium ion (Ca²⁺) of calcium oxalate was substituted to the aluminium ion (Al³⁺) of the alum, which damaged the calcium oxalate structure. Lectin attached to the surface of raphides was dissolved in alum solution and consequently its structure was denatured. The cholate in the bile juice formed the complex with the oxalate anion or the calcium cation. Moreover, the enzymes activated by Lactobacillus or Bifidobacterium during the fermentation promoted the fragmentation of oxalate. Conclusion : The adjuvant materials damaged the raphides by denaturing or degrading the calcium oxalate, resulting in the reduction of acrid irritation. Further experimental studies would support the toxicity reduction mechanism of the processing.

• The korean journal of orthodontics
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• v.51 no.6
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• pp.366-374
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• 2021

Objective: This study investigated the impact of a single piezocision in the maxillary alveolar process on the speed of tooth movement. The null hypothesis was that the speed of tooth movement will be equal with and without piezocision. Methods: All maxillary molars on one side were moved against the combined incisors in 10 ten-week-old male Wistar rats. Under general anesthesia, a force of 25 cN was applied on either side using a Sentalloy closed coil spring. After placing the orthodontic appliance, vertical corticision was performed using a piezotome under local anesthesia, 2 mm mesial from the mesial root of the first molar on a randomly selected side; the other side served as the control. At the beginning of the treatment, and 2 and 4 weeks later, skull micro-computed tomography was performed. After image reconstruction, the distance between the mesial root of the first molar and the incisive canal, and the length of the mesial root of the first maxillary molar were measured. Moreover, the root resorption score was determined as described by Lu et al. Results: Significantly higher speed of tooth movement was observed on the corticision side; thus, the null hypothesis was rejected. The loss of root length and root resorption score were significantly more pronounced after piezocision than before. A strong correlation was observed between the speed of tooth movement and root resorption on the surgical side, but the control side only showed a weak correlation. Conclusions: Piezocision accelerates orthodontic tooth movement and causes increased root resorption.

• The Korean Journal of Applied Statistics
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• v.34 no.5
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• pp.795-806
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• 2021

Recently, as text data through online channels have become vast, there is a growing interest in research that summarizes and analyzes them. One of the fundamental analyses of text data is to extract potential topics. Although the researcher may read all the data and summarize the contents one by one, it is not easy to deal with large amounts of data. Blei and Lafferty (2007) and Blei et al. (2003) proposed topic modeling methods for extracting topics using a statistical model. Since the text data is generally collected over time, it is worthwhile to monitor the topic's changes. In this study, we propose a topic index based on the results of the topic model. In addition, a control chart, a representative tool for statistical process management, is applied to monitor the topic index over time. As a practical example, we use text data collected from Blue House National Petition boards between March 5, 2018, and March 5, 2020.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.721-728
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• 2019

The purpose of this study was to evaluate the relationship between bone mineral density (BMD) and body composition (BC) or backmuscle strength (BS). Sixty-one participants were measured by BMD using ultrasound bone densitometry and Inbody for BC (i.e., SLM=Soft lean mass, SMM=Skeletal muscle mass, FS=Fitness score. et al.), BS after self-questionnaire for life cycle. This study was performed after approving Institutional Review Board and obtaining the informed concent from all participants. Participants was divided into two group by BMD T-score; $T-score{\geq}-1.0$, T-score<-1.0. Statistical analysis was performed by using SPSS ver. 22.0(USA), Spearma test for correlation between BMD and BC or BS. BMD or SLM, BS was increased with increasing physical activity or body mass index. SMM or SMM, FS of BMD $T-score{\geq}-1.0$ group was higher than that of T-score <-1.0 group as well as BS(p>0.05). BMD T-score was correlated positively with SLM(r= 0.424) or SMM(r= 0.431) in men, as well as in women(p<0.05). BS was correlated positively with SLM or SMM, FS. BS was significantly positive correlated with BMD in women group (r= 0.591, p= 0.001), but not in men group. We concluded that BMD is the relationship with SLM or SMM, as well as BS in women.

• Structural Engineering and Mechanics
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• v.76 no.6
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• pp.687-708
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• 2020

Openings in steel plate shear walls (SPSWs) are usually used for decorative designs, crossing locations of multiple utilities and/or structural objectives. However, earlier studies showed that generating an opening in an SPSW has a negative effect on the cyclic performance of the SPSW. Therefore, this study proposes tripling or doubling the steel-sheet-plate (SSP) layer and stiffening the opening of the SPSW to provide a solution to undesirable opening effects, improve the SPSW performance and provide the infill option of potential strengthening measures after the construction stage. The study aims to investigate the impact of SSP doubling with a stiffened opening on the cyclic behaviour, expand the essential data required by structural designers and quantify the SPSW performance factors. Validated numerical models were adopted to identify the influence of the chosen parameters on the cyclic capacity, energy dissipation, ductility, seismic performance factors (SPF) and stiffness of the suggested method. A finite Element (FE) analysis was performed via Abaqus/CAE software on half-scale single-story models of SPSWs exposed to cyclic loading. The key parameters included the number of SSP layers, the opening size ratios corresponding to the net width of the SSP, and the opening shape. The findings showed that the proposed assembly method found a negligible influence in the shear capacity with opening sizes of 10, 15, 20%. However, a deterioration in the wall strength was observed for openings with sizes of 25% and 30%. The circular opening is preferable compared with the square opening. Moreover, for all the models, the average value of the obtained ductility did not show substantial changes and the ultimate shear resistance was achieved after reaching a drift ratio of 4.36%. Additionally, the equivalent sectional area of the SSP in the twin and triple configuration of the SPSWs demonstrated approximately similar results. Compared with the single SSP layer, the proposed configuration of the twin SSP layer with a stiffened opening suggest to more sufficiency create SSP openings in the SPSW compared to that of other configurations. Finally, a tabular SPF quantification is exhibited for SPSWs with openings.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.179-185
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• 2021

We performed to explore the applicability of protocol to improve the curriculum literacy for special education pre-teachers. For this, protocol of Park et al (2018), which can be used in the educational field, was partially modified and applied to enhance the special education curriculum expertise of pre-teachers. The literacy protocol of the special education curriculum was applied as Protocols 1 and 2, and Protocol 1 was focused on adaptation the 2015 special education curriculum and understanding literacy. Protocol 2 consisted of reorganizing the subject level centering on the five subjects presented in the special education curriculum, and establishing an integrated theme setting and reorganization plan. We applied the research design during a total of 15 weeks of special education curriculum subjects. The class format was flipped learning (e.g, pre-video lectures, theory lectures (E-Sheets), and learner-led activities (W-Sheets) for each topic was carried out. We found that pre-teachers' thought that the academic achievement and satisfaction of students with disabilities could be increased by adaptation the curriculum. Pre-teachers reported that the experience of reorganizing each subject/intersection helped improve their literacy but found it difficult.

• (The) Korean Journal of Educational Psychology
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• v.32 no.3
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• pp.549-569
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• 2018

The purpose of this study is to examine the relationship between peer rejection and victimization among schoolchildren and to test whether conflict norms in the classroom moderated this relationship. The analysis used the third year data derived from ClassNet research (Park, et al., 2017) supported by the National Research Foundation of Korea. The sample comprised fourth-grade through sixth-grade students in 52 classrooms of 7 elementary schools in South Korea (N = 1194). A series of multi-level analyses were performed to fulfill the study's purpose using variables obtained by peer nomination, such as social rejection, victimization, bullying perpetration, and teacher-student conflict. The results found that boys experienced more victimization than girls and peer rejection significantly increased victimization. Furthermore, conflict norms in the classroom moderated the relationship between peer rejection and victimization. Peer rejection significantly increased the extent of victimization in classrooms with relatively high levels of conflict norms. The study concludes with a discussion on the significance of conflict norms and the educational implications of the results with a focus on ways that teachers can facilitate healthier classroom environments.