• Journal of Life Science
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• v.34 no.7
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• pp.485-492
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• 2024

Sea cucumbers contain more than 50% protein in their solid content, and they also possess various bioactive substances such as saponins and mucopolysaccharides. This study analyzed the activities of various enzymes derived from Bacillus and lactic acid bacteria and determined to degrade the components of sea cucumbers. Among the analyzed strains, B. subtilis K26 showed the highest activities in protease and xylanase and relatively high activity in cellulase. Accordingly, samples of sea cucumber and water were mixed in equal proportions, sterilized, and then fermented by inoculating them with B. subtilis K26. Following this, a higher amino acid content was observed between 1.5 and 7.5 hr, a lower residual solid content in this time, and a lesser fermentation odor. The saponin content in fermented sea cucumber powder extracted with butanol was measured to be 1.12 mg/g. The chondroitin sulfate content was evaluated to be 5.11 mg/g in raw sea cucumber. The total polyphenol content, flavonoid content, and antioxidant activities were 6.95 mg gallic acid equivalent/g, 3.69 mg quercetin equivalent/g, and 3.69 mg quercetin equivalent/g in raw sea cucumber, respectively. Moreover, the DNA damage protective effect of fermented sea cucumber extract was found to be concentration-dependent, with a very strong effect at very low concentrations. Overall, we suggest that sea cucumber fermented with B. subtilis K26 has a high potential as a food for inhibiting oxidation, enhancing immunity, and improving muscle function in the human body thanks to its high free amino acid content.

• Food Science and Preservation
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• v.31 no.1
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• pp.112-125
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• 2024

This study determined the relationships between the total anthocyanin content in apple skin and the total polyphenols, flavonoids, proanthocyanidins, and soluble solids contents in the flesh of cold-stored Fuji apples. Total anthocyanin content in apple skin ranged from 0.130±0.005 mg CE/g fw to 0.262±0.028 mg CE/g fw, and the overall average was 0.200±0.008 mg CE/g fw. The total polyphenolic compounds in the flesh was ranged from a 4.283±0.141 mM GAE/g fw to 8.207±0.234 mM GAE/g fw, and the average content was 6.275±0.177 mM GAE/g fw. The total flavonoid content ranged from 4.510±0.080 mM QE/g fw to 2.467±0.458 mM QE/g fw, and the average total flavonoid content was about 3.586 mM QE/g fw. The total proanthocyanidin content was relatively high, ranging from 3.475±0.577 mM EE/g fw to 6.816±0.277 mM EE/g fw, and the soluble solid in the flesh was about 12 °Brix to 14 °Brix. The DPPH radical scavenging activity of extracts from apple flesh ranged from 66.36% to 94.99%, and the ascorbate equivalent concentration was 0.482 mM. The ABTS radical scavenging activity was 99.12% to 99.9%, indicating a higher inhibitory activity than the DPPH inhibitory activity, and the ascorbate equivalent concentration was 0.486 mM. The correlation between the total anthocyanin and total polyphenolic compounds was y = 15.192x + 3.2169 (R²=0.2748), but the concentration of total polyphenolic compounds increased when the total anthocyanin content was increased. The correlation equation of total anthocyanin with total flavonoids was y = 15.18x + 0.5555 (R²=0.6226), with total proanthocyanin was y = 14.918x + 2.3422 (R²=0.3372), and with soluble solid was y = 10.558x + 11.126 (R²=0.1925), indicating that the correlation of total anthocyanin with total flavonoid was higher than that with soluble solid.

• Food Science and Preservation
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• v.30 no.4
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• pp.669-682
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• 2023

The production of distilled soju by fermenting nonsteamed rice was evaluated using commercial enzyme products. White koji and modified nuruk had alpha-amylase activities of 31.90 U/g and 3,532.71 U/g, respectively, and gluco-amylase activities of 698.32 U/g and 4,899.58 U/g, respectively. The enzyme products had activities of 5,604.15-225,182.00 U/g and 13,517.41-120,822.41 U/g, respectively. At enzyme concentrations of >800 mg/L, the Chung-moo-purified enzyme had an alcohol productivity of ≥19%. Nurukzyme R400, Sanferm Yied, and Diazyme X4 exhibited alcohol productivities of >19% at concentrations of >600 mg/L. The alcohol content of the vacuum distillates was 41.31%-44.86%. The volatile component with the alcohol content adjusted to 25% was analyzed and principal component analysis was performed. The volatile components in white koji, Diazyme X4, and Sanferm Yield were similar. The modified nuruk treatment group had a relatively high ethyl lactate content compared to the white koji treatment group. The Nurukzyme R400 treatment group had high contents of butyric acid and ethyl butyrate. The Chung-moo-purified enzyme was characterized by a low component content. Thus, when enzyme products were used in nonsteamed rice fermentation, no effect on the alcohol productivity and quality of vacuum distilled soju was observed, suggesting that it can replace white koji and modified nuruk.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.632-644
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• 2022

Purpose To determine the incidence of atypical ductal hyperplasia (ADH) in needle biopsy and the upgrade rate to carcinoma, and to evaluate difference in findings between the upgrade and non-upgrade groups. Materials and Methods Among 9660 needle biopsies performed over 48 months, we reviewed the radiologic and histopathologic findings of ADH and compared the differences in imaging findings (mammography and breast US) and biopsy methods between the upgrade and non-upgrade groups. Results The incidence of ADH was 1.7% (169/9660). Of 112 resected cases and 30 cases followed-up for over 2 years, 35 were upgraded to carcinoma (24.6%, 35/142). The upgrade rates were significantly different according to biopsy methods: US-guided core needle biopsy (USCNB) (40.7%, 22/54) vs. stereotactic-vacuum-assisted biopsy (S-VAB) (16.0%, 12/75) vs. USguided VAB (US-VAB) (7.7%, 1/13) (p = 0.002). Multivariable analysis showed that only US-CNB (odds ratio = 5.19, 95% confidence interval: 2.16-13.95, p < 0.001) was an independent predictor for pathologic upgrade. There was no upgrade when a sonographic mass was biopsied by US-VAB (n = 7) Conclusion The incidence of ADH was relatively low (1.7%) and the upgrade rate was 24.6%. Surgical excision should be considered because of the considerable upgrade rate, except in the case of US-VAB.

• Journal of the Korean Society of Radiology
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• v.82 no.1
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• pp.139-151
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• 2021

Purpose To retrospectively evaluate the chest computed tomography (CT) findings of coronavirus disease 2019 (COVID-19) in patients with mild clinical symptoms at a single hospital in South Korea. Materials and Methods CT scans of 87 COVID-19 patients [43 men and 44 women; median age: 41 years (interquartile range: 26.1-51.0 years)] with mild clinical symptoms (fever < 38℃ and no dyspnea) were evaluated. Results CT findings were normal in 39 (44.8%) and abnormal in 48 (55.2%) patients. Among the 48 patients with lung opacities, 17 (35.4%) had unilateral disease and 31 (64.6%) had bilateral disease. One (2.1%) patient showed subpleural distribution, 9 (18.8%) showed peribronchovascular distribution, and 38 (79.2%) showed subpleural and peribronchovascular distributions. Twenty-two (45.8%) patients had pure ground-glass opacities (GGOs) with no consolidation, 17 (35.4%) had mixed opacities dominated by GGOs, and 9 (18.8%) had mixed opacities dominated by consolidation. No patients demonstrated consolidation without GGOs. Conclusion The most common CT finding of COVID-19 in patients with mild clinical symptoms was bilateral multiple GGO-dominant lesions with subpleural and peribronchovascular distribution and lower lung predilection. The initial chest CT of almost half of COVID-19 patients with mild clinical symptoms showed no lung parenchymal lesions. Compared to relatively severe cases, mild cases were more likely to manifest as unilateral disease with pure GGOs or GGO-dominant mixed opacities and less likely to show air bronchogram.

• Journal of Science Education
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• v.48 no.1
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• pp.15-30
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• 2024

This study aimed to analyze students' cognitive levels and the cognitive demands of mathematical concepts related to science to understand why students struggle to comprehend scientific concepts and tend to avoid learning them. Initially, the mathematics and science curricula of the 2015 revised curriculum were examined to extract learning elements related to mathematics within middle school science content. The Curriculum Analysis Taxonomy (CAT) was then employed to analyze the cognitive levels required by the learning content. In the domain of chemistry, among a total of 20 learning elements related to mathematics, 12 required an understanding at the level of initial formal manipulation (3A), while 3 necessitated comprehension at the level of later formal manipulation (3B). It was noted that cognitive logic types such as proportional reasoning, mathematical manipulation, and measurement skills were prominently employed in elements corresponding to both 3A and 3B. As for biology, out of 7 learning elements related to mathematics, 3 required an understanding at the level of initial formal manipulation (3A), and 2 necessitated comprehension at the level of later formal manipulation (3B). Elements corresponding to both 3A and 3B in biology predominantly involved correlational logic, indicating a somewhat different cognitive challenge compared to the domain of chemistry. Considering that the average percentage of middle school students capable of formal thinking, as analyzed through the GALT short form, was 12.1% for the first year, 16.6% for the second year, and 29.3% for the third year, it can be concluded that the cognitive demands of mathematics-related chemistry and biology learning content are relatively high compared to students' cognitive levels.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1526-1531
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• 2024

¹³¹I is a fission product produced in a nuclear reactor by irradiating tellurium dioxide, with a half-life of 8.02 day. The most important and widely used method for making ¹³¹I is irradiation using a nuclear reactor and post-irradiation followed by dry distillation. The advantage of the dry distillation process is that the process and the equipment are relatively simple, namely TeO₂ (m.p. 750 ℃), which can withstand heating during reactor irradiation. Based on TeO₂ irradiation by neutron following the technique of dry distillation was explained for production of ¹³¹I on a large scale. A dry distillation followed the radioisotope production operation using the 30 MW GA Siwabessy nuclear reactor to meet national demand. TeO₂ targets are 25 and 50 g irradiated for 87-100 h. The resulting ¹³¹I activity is 20.29339-368.50335GBq. According to the requirements imposed on the radionuclide purity of the preparation, the contribution of ¹³¹I training in the resulting preparation was not less than 99.9 %

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.229-248
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• 2024

This investigated the hydrogeochemical and isotopic characteristics of geothermal waters, groundwaters, and surface waters in Dongrae-gu, Busan, South Korea, in order to determine the origins of the salinity components in the geothermal waters, and their formation mechanisms and heat sources The geothermal waters are Na-Cl-type, distinct from surrounding groundwaters (Na-HCO₃^- and, Ca-HCO₃^- (SO₄, Cl)-type) and surface waters (Ca-HCO₃(SO₄, Cl)-type). This indicates the geothermal waters formed at depth as compared with the groundwaters. δ¹⁸O and δD values of the geothermal waters are relatively depleted as compared with the groundwaters, due to altitude effects and deep circulation of the geothermal waters. Helium and neon isotope ratios (³ He/⁴He and, ⁴He/²⁰Ne) of the geothermal waters plot on a single mixing line between mantle (³He = 3.76~4.01%) and crust (⁴He = 95.99~96.24 %), indirectly suggesting that the heat source is due to the decay of radioactive elements in rocks. The geothermal reservoir temperatures were calculated using the silica-enthalpy and Giggenbach models, yielding values of 82~130℃, and the depth of the geothermal reservoir is estimated to be 1.7~2.9 km below the surface. The correlation between Cl/Na and Cl/HCO₃ for the Dongrae geothermal waters requires the input of salty water. The supply of saline composition is interpreted due to the dissolution of residual paleo-seawater.

• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.97-106
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• 2024

This study utilized the non-invasive MyotonPRO^® device to analyze the stiffness in breast muscles of commercial broilers (Ross 308 and Arbor Acres) and compared these findings with data reported for Ross 708, where Woody Breast (WB) symptoms had been previously documented. The research revealed that Ross 308 and Arbor Acres displayed relatively lower stiffness values compared to Ross 708, suggesting a lack of WB expression. These results indicate differentiation in breast muscle traits across strains and underscore the necessity for further research into factors influencing WB manifestation. The study also measured additional muscle tone characteristics such as Frequency, Decrement, Relaxation, and Creep across various growth stages (2, 4, 6, and 8 weeks), finding significant variations with pronounced severity at weeks 2 and 8. An increase in stiffness was observed as the broilers aged, pointing to potential growth-related or stress-induced changes affecting WB severity. A strong positive correlation was established between increased breast meat weight and WB severity, highlighting that heavier breast meat could exacerbate the condition. This correlation is vital for the poultry industry, suggesting that weight management could help mitigate WB effects. Moreover, the potential for genetic selection and breeding strategies to reduce WB occurrence was emphasized, which could aid in enhancing management practices in commercial poultry production. Collectively, these insights contribute to a deeper understanding of WB in broilers and propose avenues for future research and practical strategies to minimize its impact.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.1
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• pp.55-73
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• 2024

Unicorn companies are attracting attention around the world as they are recognized for their high corporate value in a short period of time as an innovative business models. Their growth process presents good lessons for the startup ecosystem and have a positive impact on national economic development and job creation. However, previous studies related to unicorn companies are focused on 'event studies' and 'case studies' such as characteristics of founders, environmental factors, business models and success/failure cases of companies already recognized as unicorns rather than a multifaceted approach. The occurrence of unicorn companies and Macroscopic analysis of related factors is lacking. Against this background, this study are considering the characteristics of unicorns examined through previous research and the current status unicorns with a high proportion of technology companies, the purpose was to analyze the impact of the country's technological competitiveness, such as 'technology human resource index', 'R&D index', and 'technology infrastructure index', on the increase in unicorn companies. For statistical analysis, data published by various international organizations, the Bank of Korea, and Statistics Korea from 2017 to 2020 and unicorn company data compiled by CB Insights were used as panel data for 44 countries to be tested by multiple regression analysis. As a result of the study, it was confirmed that the number of science majors had a positive (+) effect on the increase of unicorn companies in the case of technology human resource index, and in the case of R&D index, the total amount of R&D investment had a positive (+) effect on the increase of unicorn companies, while the number of Triad Patents Families and the number of scientific and technological papers published had a negative (-) effect on the increase of unicorn companies. Finally, in the case of technology infrastructure index, it was confirmed that the number of the world's 500th-ranked universities had a positive (+) effect on the increase of unicorn companies. This study is the first to reveal the causal relationship between national technological competitiveness and unicorn company growth based on country-specific and time-series empirical data, which were insufficiently covered in previous studies. and compared to the UN's ranking of the global industrial competitiveness index and the OECD's total R&D investment by country, Korea is considered to have technological and growth potential, while the number of unicorn companies driving growth as leaders of the innovative economy is relatively small, so the research results can be used when establishing policies to discover and foster unicorn companies in the future.