• International Journal of Stem Cells
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• v.16 no.1
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• pp.78-92
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• 2023

Background and Objectives: This study aims to clarify the systems underlying regulation and regulatory roles of hydrogen combined with 5-Aza in the myogenic differentiation of adipose mesenchymal stem cells (ADSCs). Methods and Results: In this study, ADSCs acted as an in vitro myogenic differentiating mode. First, the Alamar blue Staining and mitochondrial tracer technique were used to verify whether hydrogen combined with 5-Aza could promote cell proliferation. In addition, this study assessed myogenic differentiating markers (e.g., Myogenin, Mhc and Myod protein expressions) based on the Western blotting assay, analysis on cellular morphological characteristics (e.g., Myotube number, length, diameter and maturation index), RT-PCR (Myod, Myogenin and Mhc mRNA expression) and Immunofluorescence analysis (Desmin, Myosin and 𝛽-actin protein expression). Finally, to verify the mechanism of myogenic differentiation of hydrogen-bound 5-Aza, we performed bioinformatics analysis and Western blot to detect the expression of p-P38 protein. Hydrogen combined with 5-Aza significantly enhanced the proliferation and myogenic differentiation of ADSCs in vitro by increasing the number of single-cell mitochondria and upregulating the expression of myogenic biomarkers such as Myod, Mhc and myotube formation. The expressions of p-P38 was up-regulated by hydrogen combined with 5-Aza. The differentiating ability was suppressed when the cells were cultivated in combination with SB203580 (p38 MAPK signal pathway inhibitor). Conclusions: Hydrogen alleviates the cytotoxicity of 5-Aza and synergistically promotes the myogenic differentiation capacity of adipose stem cells via the p38 MAPK pathway. Thus, the mentioned results present insights into myogenic differentiation and are likely to generate one potential alternative strategy for skeletal muscle related diseases.

• Journal of Biomedical Engineering Research
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• v.45 no.3
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• pp.128-137
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• 2024

It is necessary to develop a pulsatile Extracorporeal Membrane Oxygenator (p-ECMO) with counter-pulsation control(CPC), which ejects blood during the diastolic phase of the heart rather than the systolic phase, due to the known issues with conventional ECMO causing fatal complications such as ventricular dilation and pulmonary edema. A promising method to simultaneously detect the pulsations of the heart and p-ECMO is to analyze blood pressure waveforms using deep neural network technology(DNN). However, the accurate detection of cardiac rhythms by DNNs is challenging due to various noises such as pulsations from p-ECMO, reflected waves in the vessels, and other dynamic noises. This study aims to evaluate the accuracy of DNNs developed for CPC in p-ECMO, using human-like blood pressure waveforms reproduced in an in-vitro experiment. Especially, an experimental setup that reproduces reflected waves commonly observed in actual patients was developed, and the impact of these waves on DNN judgments was assessed using a multiple DNN (m-DNN) that provides accurate determinations along with a separate index for heartbeat recognition ability. In the experimental setup inducing reflected waves, it was observed that the shape of the blood pressure waveform became increasingly complex, which coincided with an increase in harmonic components, as evident from the Fast Fourier Transform results of the blood pressure wave. It was observed that the recognition score (RS) of DNNs decreased in blood pressure waveforms with significant harmonic components, separate from the frequency components caused by the heart and p-ECMO. This study demonstrated that each DNN trained on blood pressure waveforms without reflected waves showed low RS when faced with waveforms containing reflected waves. However, the accuracy of the final results from the m-DNN remained high even in the presence of reflected waves.

• Clinical Endoscopy
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• v.56 no.6
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• pp.761-768
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• 2023

Background/Aims: Self-expandable metallic stents (SEMSs) are widely adopted for the palliation of dysphagia in patients with malignant esophageal strictures. An important adverse event is the development of SEMS-induced esophagorespiratory fistulas (SEMS-ERFs). This study aimed to assess the risk factors related to the development of SEMS-ERF after SEMS placement in patients with esophageal cancer. Methods: This retrospective study was performed at the Instituto do Cancer do Estado de São Paulo. All patients with malignant esophageal strictures who underwent esophageal SEMS placement between 2009 and 2019 were included in the study. Results: Of the 335 patients, 37 (11.0%) developed SEMS-ERF, with a median time of 129 days after SEMS placement. Stent flare of 28 mm (hazard ratio [HR], 2.05; 95% confidence interval [CI], 1.15-5.51; p=0.02) and post-stent chemotherapy (HR, 2.0; 95% CI, 1.01-4.00; p=0.05) were associated with an increased risk of developing SEMS-ERF, while lower-third tumors were a protective factor (HR, 0.5; 95% CI, 0.26-0.85; p=0.01). No difference was observed in overall survival. Conclusions: The incidence of SEMS-ERFs was 11%, with a median time of 129 days after SEMS placement. Post-stent chemotherapy and a 28 mm stent flare were associated with a higher risk of SEMS-ERF.

• The Korean Journal of Coaching Psychology
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• v.7 no.3
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• pp.127-152
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• 2023

Employees' innovative behavior is crucial for organizations to maintain competitiveness and foster growth. Empowering leadership coaching styles, which delegate authority and responsibility to organizational members while respecting their autonomy, create opportunities for members to solve problems and present innovative ideas. Drawing on signal theory, this study aims to clarify the process through which political skill influences employees' work innovative behavior, mediated by empowering leadership. Additionally, we examine whether the leader's implicit followership prototype moderates the relationship between employees' political skills and empowering leadership. Survey data were collected in two rounds with a two-week lag from 180 employees in a manufacturing company in South Korea. The results revealed that political skill was related to empowering leadership and subsequent work innovative behavior. Furthermore, the leaders' implicit followership prototype strengthened the relationship between political skill and empowering leadership. This study provides meaningful theoretical and practical insights into empowering coaching styles.

• Clinical Endoscopy
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• v.56 no.6
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• pp.744-753
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• 2023

Background/Aims: This study aimed to evaluate the prevalence and natural progression of subepithelial lesions (SELs) in the upper gastrointestinal (UGI) tract. Methods: The medical records of patients with UGI SELs who underwent endoscopic screening at eight university hospitals between January and December 2010 were retrospectively investigated. The follow-up evaluations were performed until December 2016. Results: UGI SELs were found in 1,044 of the 65,233 participants screened (endoscopic prevalence, 1.60%; the total number of lesions, 1,062; mean age, 55.1±11.2 years; men, 53.6%). The median follow-up period was 48 (range, 8-74) months. SELs were most frequently found in the stomach (63.8%) and had a mean size of 9.9±6.1 mm. Endoscopic ultrasonography (EUS) was performed in 293 patients (28.1%). The most common lesions were leiomyomas, followed by gastrointestinal stromal tumors (GISTs), and ectopic pancreas. The proportions of SELs with malignant potential according to size were 3% (<1 cm), 22% (1-2 cm), 27% (2-3 cm), and 38% (≥3 cm). In gastric SELs larger than 1 cm, resections were performed in 20 patients because of an increase in size, of which 12 were found to be GISTs. Conclusions: The prevalence of UGI SELs was 1.60%. Further, 23% of gastric SELs ≥1 cm were precancerous lesions, most followed by EUS and clinical decisions without initial pathological confirmation.

• The Korean Journal of Coaching Psychology
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• v.7 no.3
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• pp.1-26
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• 2023

This study aims to explore how professors at community colleges are experiencing career guidance for their students, uncovering key components related to causes, phenomena, contexts, coping strategies, etc., and deriving a paradigm model to structurally. To achieve this objective, focus group interviews were conducted with a total of 23 community college professors, and the results were analyzed using the grounded theory method (Strauss & Corbin, 1998). The analysis yielded 17 categories and 31 subcategories. The central phenomenon in the career guidance of community college professors was categorized into two groups: the distress experience in career guidance and attitude changes toward interactions with students..Three categories of causal conditions contributing to the occurrence of the central phenomenon were identified: professors' lack of expertise in career guidance, students' scope and needs for career guidance, and students' low interest and expectations. Additionally, four contextual conditions corresponding to special situations or circumstances that contributed to the central phenomenon were identified: increasing demand for career guidance, excessive burden and time constraints for career guidance, lack of communication about career guidance at the institutional level, and limitations within the career guidance support system. Furthermore, the study uncovered patterns of action-interaction, mediating conditions, and outcomes. This study is expected to contribute to a better understanding of the actual experiences of college professors in the career guidance process, and to stimulate consideration of the types of support required for effective career guidance for college professors in the future.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.1
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• pp.1-21
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• 2024

Recently, venture capital investment has been shrinking globally due to high interest rates and economic slowdown. Korea is no exception. Due to the downturn in the M&A and public markets, increasing economic uncertainty, and the aftermath of corporate bankruptcies, venture capitalists are facing many difficulties in raising funds. In the changed economic environment, the investment decision factors of venture capitalists have also changed. However, studies on VCs' investment decisions have focused on the general economic environment. This study examines how VCs' investment decision-making factors change during economic recessions and booms. To this end, we interviewed active investors who have experienced both economic recessions and booms to compare how VCs' investment decision factors change: 1) personal characteristics of founders, 2) experience of founders, 3) product/service, 4) market, 5) financial situation, 6) contract terms and 7) venture capital co-investment. The results showed that founder's personal characteristics, experience, and product/service were more important during the economic recession. Market is slightly more important during economic booms. The importance of financial situation and investment conditions increased sharply during the recession compared to the boom. Finally, venture capital co-investment did not differ significantly between recessions and booms. By understanding the investment decision-making factors of venture capitalists in the recent difficult venture investment environment, this study aims to help startups raise funds and survive in a difficult market.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.208-222
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• 2023

With the recent revision of 「Act on Promotion of the Transportation Convenience of Mobility Disadvantaged Persons」 and the Enforcement Regulations of the Act, bus business operators must introduce low-floor buses when scrapping buses. On the other hand, in the case of routes where low-floor buses cannot be operated, bus business operators can be exempted from introducing low-floor buses with the approval of their transportation administrative agency according to Article 4-2 of 「Enforcement Regulation of the Act on Promotion of the Transportation Convenience of Mobility Disadvantaged Persons」. According to the data from the Korea Bus Transportation Associations Federation, approximately 5.9% of all city bus routes were surveyed as the exceptions to introducing low-floor buses. Nevertheless the proportion is expected to increase because some regions with difficulties introducing low-floor buses are not included when calculating the proportion. By confirming the process of approving exceptions for introducing low-floor buses through local governments, there was no specific examination method or standard for approval of exceptions. Hence, there is the problem that some routes are approved as exceptions to introducing low-floor buses, even though low-floor buses can be operated on those routes. Therefore, this study aims to develop a manual that can objectively diagnose the overall operation environment of low-floor buses, such as road geometry and road facilities. Future research plans to apply it to more cases and improve it for more precise application in various contexts.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.124-140
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• 2023

The rapid growth in shared E-scooters worldwide has led to many studies on the topic. The results of these studies are still in the early stages, and the main factors affecting trips are being identified. In particular, the development of trip-generation models is very important for transportation planning, and a new transportation mode for developing the models for shared E-scooters is lacking both domestically and internationally. This study aims to develop a trip generation model for shared E-scooters using significant variables by thoroughly reviewing previous studies. The trip characteristics of major service areas and other areas may differ owing to the trip characteristics of the mode. The trip generation models were developed based on the service trip density by dividing the areas by service level. The factors affecting shared E-scooter trips in major service areas included the presence of universities, closeness centrality, and cultural areas, while factors affecting the trips in minor service areas included the presence of universities, betweenness centrality, and trip distance. The developed models provide basic information that can be used to establish transport policies for introducing shared E-scooters in cities in the future.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.6
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• pp.117-132
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• 2023

With the recent spread of COVID-19, the size of the online shopping market continues to increase, and various online platforms are appearing in the market, and many small and medium businesses are entering the platform. As the recent increase in the use of the platform by small andmedium businesses as raised the issue of appropriate platform fees, the need for social discussions on the use of the platform and fees is raised. Currently, most discussions regarding fees primarily focus on specific cases from a negative perspective, and discussions that comprehensively consider the platform's utilization value and fees are insufficient. Therefore, this study aims to systematically and comprehensively understand platform fees by considering the value of using platform services and commission costs together. To achieve this, the economic value of each platform service was estimated and analyzed in detail. It selected two industries that are actively using online platforms, delivery services and e-commerce, and paid attention to changes in expected profits generated by sellers using platform services, and compared and analyzed expected profits based on estimated sales and costs for each scenario, such as whether sellers entered the platform and whether they used the service. As a result of the study, our results that entering the platform and using the platform service enable sales increase and cost reduction, which have a positive effect on the seller's expected profit. Through this study, we intend to understand platform fees from the perspective of user fees for platform service use and value acquisition, and based on this, estimate the economic value of platform services and fees to expand the value and cost of using platform services to a comprehensive and systematic discussion.