• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.4
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• pp.187-194
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• 2023

Purpose: A mismatched size in the post and post space is a common problem during post-fixation. Since this discordance affects the bonding strength of the fiber-reinforced composite resin post (FRC Post), a corresponding luting agent is required. The aim of this study was to evaluate the bonding strength of the FRC post according to the fitness of the fiber post and the type of luting agent. Materials and Methods: Thirty mandibular premolar were endodontic-treated and assigned to two groups according to their prepared post space: Fitting (F) and Mismatching (M). These groups were further classified into three subgroups according to their luting agent: RelyX Unicem (ReX), Luxacore dual (Lux), and Duolink (Duo). A push-out test was performed to measure the push-out bond strengths. The fractured surfaces of each cross-section were then examined, and the fracture modes were classified. Results: In the ReX and Duo subgroups, the F group had a higher mean bond strength; however, the Lux subgroup had no significant difference between the F and M groups. In the analysis of the failure modes, the ReX subgroup had only adhesive failures between the cement and dentin. Conclusion: The result of this study showed that the bond strength of an FRC post was influenced by the type of luting agent and the mismatch between the diameter of the prepared post space and that of the post.

• Korean Journal of Ecology and Environment
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• v.57 no.1
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• pp.1-16
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• 2024

Most wetlands worldwide have suffered from extensive human exploitation. Unfortunately they have been less explored compared to river and lake ecosystems despite their ecological importance and economic values. This is the same case in Korea. This study was aimed to estimate the assemblage attributes and distribution characteristics of benthic macroinvertebrates for fifty wetlands distributed throughout subtropical Jeju Island in 2021. A total of 133 taxa were identified during survey periods belonging to 53 families, 19 orders, 5 classes and 3 phyla. Taxa richness ranged from 4 to 31 taxa per wetland with an average of 17.5 taxa. Taxa richness and abundance of predatory insect groups such as Odonata, Hemiptera and Coleoptera respectively accounted for 67.7% and 68.2% of the total. Among them Coleoptera were the most diverse and abundant. Taxa richness and abundance did not significantly differ from each wetland type classified in accordance with the National Wetland Classification System. There were three endangered species (Clithon retropictum, Lethocerus deyrolli and Cybister (Cybister) chinensis) and several restrictively distributed species only in Jeju Island. Cluster analysis based on the similarity in the benthic macroinvertebrate composition largely classified 50 wetlands into two major clusters: small wetlands located in lowland areas and medium-sized wetlands in middle mountainous regions. All cluster groups displayed significant differences in wetland area, long axis, percentage of fine particles and macrophyte composition ratio. Indicator Species Analysis selected 19 important indicators with the highest indicator value of Ceriagrion melanurum at 63%, followed by Noterus japonicus (59%) and Polypylis hemisphaerula (58%). Our results are expected to provide fundamental information on the biodiversity and habitat environments for benthic macroinvertebrates in wetland ecosystems, consequently helping to establish conservation and restoration plans for small wetlands relatively vulnerable to human disturbance.

• Journal of Plant Biotechnology
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• v.50
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• pp.275-289
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• 2023

Since the implementation of the Living Modified Organisms (LMOs) Act in 2008, approximately 10 million tons of genetically modified corn, soybean, potato, canola, and other crops have been imported into South Korea. The import approval procedures have been completed for approximately 191 cases that include seven crops. Of these, approximately 90 cases, excluding crossbreeds of approved LMOs, were reviewed via consultation risk evaluation in four areas: human health, crop culture, natural ecology, and marine fishery environment. LMO developers in South Korea, who are major stakeholders in the import of LMO crops produced overseas, have raised concerns regarding procedural inefficiency in consultation reviews and the need of excessive reviews that are unsuitable for food-feed processing purposes. These procedures reflect the perspective of consultation agencies that deviate from the nature of risk assessment and demand specific supplementary data that do not reflect familiarity and substantial equilibrium. Based on frequent instances of unintentional environmental release of LMO crops imported into Korea, the ministries responsible for consultation insist on a review that considers the climate and natural environment of Korea. In addition, the ministries mandate that their reviews reflect the expertise of competent ministries and are based on risk assessment principles and methods in accordance with international guidelines. In this regard, considering that traits introduced into LMO crops involving familiar agricultural crops have been considered safe for more than two decades, we have suggested reasonable alternatives to several risk assessment items for agricultural LMOs. These alternatives can mitigate conflicts of interest among key stakeholders within the scope of the current LMO regulations.

• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1309-1321
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• 2023

This study was conducted by dividing L-arginine intake group (n=14) and placebo group (n=14) to investigate the effect of L-arginine intake on athletic performance, lactate, lactate dehydrogenase, and ammonia of men's college Taekwondo Kyorugi players during 8-week of intensive winter training. The L-arginine intake group consumed a total of 3 g, including 1 g for breakfast, 1 g for lunch, and 1 g for dinner, and the placebo group consumed maltodextrin in the same way. The 8-week winter training program was conducted at 70-90%HRR (heart rate reserve). Two-way repeated measures ANOVA was used for the interaction between the L-arginine intake group and the placebo group of the measured data, paired t-test was used for the difference between the periods within the group, and the difference between groups was analyzed using independent t-test. As a result, there was an interaction between groups in the average number of kicks among the performance ability through the TAAA (Taekwondo-specific aerobic anaerobic agility) test , and the main effect between groups was shown (p<.05). In addition, there was an interaction between groups and time in the kick fatigue index (p<.05). In lactate, the time-interaction were shown (p<.05) and interaction effects and inter-time main effects were observed in lactate dehydrogenase (LDH)(p<.05). In the case of ammonia, the interaction effect between the group and time was shown (p<.05). These results show that L-arginine intake can play a positive role in quickly synthesizing nitric oxide in blood vessels and expanding blood vessels to quickly remove fatigue-causing substances in the body for athletes who are easily exposed to fatigue after high-intensity training for male college Taekwondo Kyorugi players. Therefore, it is recommended to take L-arginine as a way to improve the performance of high-intensity elite Taekwondo Kyorugi players and recover from fatigue.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.29 no.1
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• pp.14-27
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• 2024

Unlike the shelf sand ridges moribund in motion, nearshore sand ridges are highly mobile, sensitive to changes in ocean environments, thereby becoming of particular interest with respect to morphological changes. About 5 km off the Daesan port, the Jangan Sand Ridge has been undergoing severe subsea morphological change over the past two decades. Understanding the nature of sand ridges is critical to elucidate the causes of morphological changes. In this context, this study aims at understanding the characteristics and distribution patterns of surface sediments of the ridge and its vicinity. For this purpose, 227 sediment samples were acquired using a grab-sampler, the grain sizes being analysed by the sieve-pipette method. In addition, comparison of grain sizes in sediments between 1997 and 2021 was made in order to investigate the 25-years change in sediment composition. Surface sediments along the ridge axis are fine to medium sands with 2-3 phi in mean grain size, whereas, in the trough of ridge, the sediments are composed of gravels and muddy sandy gravels with mean sizes of -2 to -6 phi. Sediments in the crest of the ridge are well-sorted with normal distribution, on the other hand, the basal sediments are poorly-sorted and positively skewed. Along the ridge crest, the sediments are negatively skewed. From 1997 to 2021, the ridge sediments became largely coarser about 0.5 phi. Such coarsening trend in mean grain size can be explained either by elimination of fine sediments during high waves in winter or elimination of fines suspended during sand mining activities in the past. Spatial distribution pattern of surface sediments shows that ca. 30 m thick of the sand ridge itself overlies the thin relict gravels. The strong asymmetry of sand ridge, the exposure of ridge base, and reworked gravel lags suggest that Jangan sand ridge is probably sediment-deficit and hence erosive in nature at present.

• Journal of the Korean Society of Radiology
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• v.85 no.3
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• pp.618-630
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• 2024

Purpose To compare the efficacy and safety of radiofrequency ablation (RFA) and ethanol ablation (EA) followed by RFA in treating mixed cystic and solid thyroid nodules. Materials and Methods We included 243 nodules from 243 patients who underwent RFA for mixed cystic and solid benign nodules. The nodules were divided into two groups (RFA alone and EA + RFA). We evaluated volume reduction rate (VRR), therapeutic success rate, improvement in symptomatic and cosmetic issues, complications, and adverse effects. Results The RFA group included 204 patients, and the EA + RFA group included 39 patients. The long-term success rates in the RFA only and EA + RFA groups were 90.2% and 97.4%, respectively. The mean VRR at the last follow-up in the RFA and EA + RFA groups were 81.6% and 87.2%, respectively. Therapeutic results were similar in both groups at the last followup. Cosmetic and symptomatic problems markedly improved in both groups. No major complications were observed. Conclusion Both RFA alone and EA + RA are safe and effective methods for treating mixed cystic and solid thyroid nodules, although EA + RFA is slightly more effective.

• Journal of Wetlands Research
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• v.26 no.2
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• pp.147-159
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• 2024

Lack of streamflow observations makes model calibration difficult and limits model performance improvement. Satellite-based remote sensing products offer a new alternative as they can be actively utilized to obtain hydrological data. Recently, several studies have shown that artificial intelligence-based solutions are more appropriate than traditional conceptual and physical models. In this study, a data-driven approach combining various recurrent neural networks and decision tree-based algorithms is proposed, and the utilization of satellite remote sensing information for AI training is investigated. The satellite imagery used in this study is from MODIS and SMAP. The proposed approach is validated using publicly available data from 25 watersheds. Inspired by the traditional regionalization approach, a strategy is adopted to learn one data-driven model by integrating data from all basins, and the potential of the proposed approach is evaluated by using a leave-one-out cross-validation regionalization setting to predict streamflow from different basins with one model. The GRU + Light GBM model was found to be a suitable model combination for target basins and showed good streamflow prediction performance in ungauged basins (The average model efficiency coefficient for predicting daily streamflow in 25 ungauged basins is 0.7187) except for the period when streamflow is very small. The influence of satellite remote sensing information was found to be up to 10%, with the additional application of satellite information having a greater impact on streamflow prediction during low or dry seasons than during wet or normal seasons.

• Journal of Korean Society of Forest Science
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• v.113 no.1
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• pp.118-130
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• 2024

Rehabilitation of mining areas can reduce damage to ecosystems. However, the effects of rehabilitation on ecosystem services (ESs) and its contribution to local communities are not well known. Thus, the aims of this study were to clearly identify the ES beneficiaries affected by mining activities, to determine how the beneficiaries profit from surrounding areas in cooperation with local stakeholders, and to manage the rehabilitation areas for the ESs that the beneficiaries want. This study chose 18 ESs (4 provisioning, 7 regulating, 5 cultural, and 2 habitat services) based on The Economics of Ecosystems and Biodiversity. A semi-structured questionnaire survey using an 11-point Likert scale was conducted among 87 community residents to investigate social awareness and identify key ESs. The survey results from two local communities showed high awareness and demands mainly on cultural (mental and physical health, aesthetic appreciation, and recreation) and regulating services (local climate and air quality, and moderation of extreme events). These services were related to the daily lives of residents in local communities, provided positive benefits, and potentially improved the residents' future livelihoods. However, the average questionnaire scores were limited to 6-7 points, indicating that the benefits to local communities were meager. The residents' awareness of provisioning service was negative, even if it provided goods and profit opportunities. This indicated a disconnection between local communities and provisioning services due to forest rehabilitation that did not consider local communities that traditionally relied on specific provisioning services before the onset of mining activities. Future forest rehabilitation in abandoned mine areas must consider the welfare of local communities for sustainable use of rehabilitated forests and enhancing ESs. In this study, only a qualitative evaluation based on frequency analyses was conducted. The quantification and valuation of key ESs are warranted in the future to promote ESs from forest rehabilitation in abandoned mine areas. The study results would be useful for developing site-specific ES promotion strategies for reforesting mine areas.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.37-45
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• 2024

Purpose: This study aimed to examine the clinical features and determinants of macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMP) and to assess the differences in the time to fever resolution between doxycycline (DXC), tosufloxacin (TFX) and corticosteroid (CST) as second-line treatment. Methods: We retrospectively analyzed the medical records of patients under the age of 18 who were admitted to Nowon Eulji University Hospital between July 2018 and February 2020, diagnosed with mycoplasma pneumonia. Macrolide resistance was confirmed by detecting point mutations in the 23S rRNA gene. MUMP was clinically defined by persistent fever (≥38.0℃) lasting for 72 hours or more after the initiation of macrolide treatment. In cases of MUMP, patients were treated with an addition of CST, or the initial macrolide was replaced either DXC or TFX. Results: Out of 157 cases of mycoplasma pneumonia, 83 cases (52.9%) did not respond to macrolides. Patients with MUMP exhibited significantly higher C-reactive protein (CRP) levels (3.2±3.0 vs. 2.4±2.2 mg/dL, P=0.047), more frequent lobar/segmental infiltrations or pleural effusions (56.6% vs. 27.0%, P<0.001; 6.0% vs. 0.0%, P=0.032), and a higher prevalence of 23S rRNA gene mutations (96.4% vs. 64.6%, P<0.001) when compared to those with macrolide-susceptible M. pneumoniae pneumonia. In terms of second-line treatment, 15 patients (18.1%) responded to CST, 30 (36.1%) to DXC, and 38 (45.8%) to TFX. The time to defervescence (TTD) after initiation second-line treatment was significantly shorter in the CST group compared to the DXC (10.3±12.7 vs. 19.4±17.2 hours, P=0.003) and TFX groups (10.3±12.7 vs. 25.0±20.1 hours, P=0.043), with no significant difference observed between the DXC and TFX groups (19.4±17.2 vs. 25.0±20.1 hours, P=0.262). Conclusions: High CRP levels, the presence of positive 23S rRNA gene mutation, lobar or segmental lung infiltration, and pleural effusion observed in chest X-ray findings were significant factors associated with macrolide unresponsiveness. In this study, CST demonstrated a shorter TTD compared to DXC or TFX. Further, larger-scale prospective studies are needed to determine the optimal second-line treatment for MUMP.

• Korean Journal of Mineralogy and Petrology
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• v.37 no.1
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• pp.1-11
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• 2024

World stone production in 2021 stood at 162.5 million tons, up by 7.5 million tons, or 4.8 percent, compared to the previous year when the production came in at 155 million tons. Six top countries with the most of stone production were China, India, Turkey, Brazil, Iran and Italy and these six countries accounted for 72.8 percent of total production in the world. Stone exports stood at $21.68 billion in 2021, up by $2.3 billion from the previous year. Exports of raw materials and processed stones stood at 54.4 million tons, up by 2.98 million tons from the previous year. In terms of aggregate exports, exports of natural stones increased by $2.3 billion to $21.7 billion while exports of artificial stones rose $2.6 billion to $13.6 billion in 2021 compared to the previous year. The average price of stone (Code: 68.02) was up by $65.2 per ton to $794.82. The price of board, processed stone, an ingredient for building materials, increased by $3.52 per square meter to $42.96 per square meter. Recycling was always the problem as the volume of the total quarry was 333.5 million tons, of which only 28.8 percent were finished products and the remaining 71.2 percent were waste generated from stone extraction and processing. Korea's stone exports stood at $1.97 million in 2021, down 38.3 percent on year, while imports were up 8.6 percent to $758.9 million. Stone exports are expected to grow to 66.1 million tons in 2025, while usage is expected to reach 108.92 million tons, or 2 billion square meters.