• Journal of Applied Biological Chemistry
• /
• v.66
• /
• pp.359-368
• /
• 2023

This study aims to explore the impact of Krill Oil (KO, Superba^TM Boost) on skin moisturization regulation. The research involved five groups: an intact control, a reference group (L-AA 100 mg/kg), and KO groups (400, 200, and 100 mg/kg), each comprising ten mice. Oral administration was conducted for 8 weeks (56 days), during which changes in body weight, hyaluronan, collagen type 1 (COL1), transforming growth factor-β1 (TGF-β1), ceramide, and water contents were analyzed in dorsal back skin tissue. Real-time PCR was employed to assess gene expression related to hyaluronic acid synthesis (HAS1, HAS2, HAS3), COL1 synthesis (COL1A1 and COL1A2), and TGF-β1. Results demonstrated that KO administration significantly increased hyaluronan content, hyaluronic acid synthesis (HAS1, HAS2, HAS3), COL1 content, COL1 synthesis (COL1A1 and COL1A2), TGF-β1 content, TGF-β1 mRNA expression, ceramide content, and water content in a concentration-dependent manner compared to the intact control. Importantly, no discernible disparities were noted between the KO and L-AA groups, even though they received equivalent oral dosages. This study accentuates the potential utility of exogenous KO in the regulation of skin moisture, thus positioning it as a promising avenue for the development of nutricosmetics. Future research endeavors should delve into the role of KO in safeguarding against both intrinsic and extrinsic aging-related skin manifestations, as well as its potential to ameliorate skin wrinkles, in conjunction with its moisturizing attributes.

• Korean Circulation Journal
• /
• v.53 no.10
• /
• pp.677-689
• /
• 2023

Background and Objectives: There is limited evidence regarding machine-learning prediction for the recurrence of atrial fibrillation (AF) after electrical cardioversion (ECV). This study aimed to predict the recurrence of AF after ECV using machine learning of clinical features and electrocardiograms (ECGs) in persistent AF patients. Methods: We analyzed patients who underwent successful ECV for persistent AF. Machine learning was designed to predict patients with 1-month recurrence. Individual 12-lead ECGs were collected before and after ECV. Various clinical features were collected and trained the extreme gradient boost (XGBoost)-based model. Ten-fold cross-validation was used to evaluate the performance of the model. The performance was compared to the C-statistics of the selected clinical features. Results: Among 718 patients (mean age 63.5±9.3 years, men 78.8%), AF recurred in 435 (60.6%) patients after 1 month. With the XGBoost-based model, the areas under the receiver operating characteristic curves (AUROCs) were 0.57, 0.60, and 0.63 if the model was trained by clinical features, ECGs, and both (the final model), respectively. For the final model, the sensitivity, specificity, and F1-score were 84.7%, 28.2%, and 0.73, respectively. Although the AF duration showed the best predictive performance (AUROC, 0.58) among the clinical features, it was significantly lower than that of the final machine-learning model (p<0.001). Additional training of extended monitoring data of 15-minute single-lead ECG and photoplethysmography in available patients (n=261) did not significantly improve the model's performance. Conclusions: Machine learning showed modest performance in predicting AF recurrence after ECV in persistent AF patients, warranting further validation studies.

• Journal of Microbiology and Biotechnology
• /
• v.34 no.5
• /
• pp.1029-1039
• /
• 2024

This study explores beneficial bacteria isolated from the roots and rhizosphere soil of Khao Rai Leum Pua Phetchabun rice plants. A total of 315 bacterial isolates (KK001 to KK315) were obtained. Plant growth-promoting traits (phosphate solubilization and indole-3-acetic acid (IAA) production), and antimicrobial activity against three rice pathogens (Curvularia lunata NUF001, Bipolaris oryzae 2464, and Xanthomonas oryzae pv. oryzae) were assessed. KK074 was the most prolific in IAA production, generating 362.6 ± 28.0 ㎍/ml, and KK007 excelled in tricalcium phosphate solubilization, achieving 714.2 ± 12.1 ㎍/ml. In antimicrobial assays using the dual culture method, KK024 and KK281 exhibited strong inhibitory activity against C. lunata, and KK269 was particularly effective against B. oryzae. In the evaluation of antimicrobial metabolite production, KK281 and KK288 exhibited strong antifungal activities in cell-free supernatants. Given the superior performance of KK281, taxonomically identified as Bacillus sp. KK281, it was investigated further. Lipopeptide extracts from KK281 had significant antimicrobial activity against C. lunata and a minimum inhibitory concentration (MIC) of 3.1 mg/ml against X. oryzae pv. oryzae. LC-ESI-MS/MS analysis revealed the presence of surfactin in the lipopeptide extract. The crude extract was non-cytotoxic to the L-929 cell line at tested concentrations. In conclusion, the in vitro plant growth-promoting and disease-controlling attributes of Bacillus sp. KK281 make it a strong candidate for field evaluation to boost plant growth and manage disease in upland rice.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.4
• /
• pp.677-684
• /
• 2024

In this paper, the design method of a step-up DC-DC converter based on PWM control was studied for solar power system application. The operating principle of the switching mode step-up type DC-DC converter was analyzed and the basic design method was studied. For photovoltaic system application, an output voltage feedback control algorithm based on PWM control was developed to enable the converter's output voltage to follow the target voltage under variable input conditions. As a procedure to verify the effectiveness of the proposed algorithm, a prototype of a step-up DC-DC converter with a single feedback output voltage was designed and made by boosting the input voltage DC 10V to DC 30V. In experiments with prototypes, it was confirmed that the output voltage of the oscilloscope and LCD accurately followed the target output voltage. In the performance evaluation test, it was confirmed that the output voltage of the oscilloscope and LCD accurately followed the target output voltage by showing an error rate within 1 [%] of the reference voltage.

• Clinical and Experimental Vaccine Research
• /
• v.13 no.2
• /
• pp.132-145
• /
• 2024

Purpose: Enterovirus 71, a pathogen that causes hand-foot and mouth disease (HFMD) is currently regarded as an increasing neurotropic virus in Asia and can cause severe complications in pediatric patients with blister-like sores or rashes on the hand, feet, and mouth. Notwithstanding the significant burden of the disease, no authorized vaccine is available. Previously identified attenuated and inactivated vaccines are worthless over time owing to changes in the viral genome. Materials and Methods: A novel vaccine construct using B-cell derived T-cell epitopes from the virulent polyprotein found the induction of possible immune response. In order to boost the immune system, a beta-defensin 1 preproprotein adjuvant with EAAAK linker was added at the N-terminal end of the vaccine sequence. Results: The immunogenicity of the designed, refined, and verified prospective three-dimensional-structure of the multi-epitope vaccine was found to be quite high, exhibiting non-allergenic and antigenic properties. The vaccine candidates bound to toll-like receptor 3 in a molecular docking analysis, and the efficacy of the potential vaccine to generate a strong immune response was assessed through in silico immunological simulation. Conclusion: Computational analysis has shown that the proposed multi-epitope vaccine is possibly safe for use in humans and can elicit an immune response.

• Korean Journal of Agricultural Science
• /
• v.51 no.2
• /
• pp.147-158
• /
• 2024

Hepatic fibrosis refers to the scarring of liver tissue, often resulting from chronic liver injury or inflammation. It is characterized by excessive deposition of extracellular matrix proteins, impairing liver function and potentially progressing to cirrhosis if left untreated. To improve the liver functions, Cordyceps militaris, a species of parasitic fungus known for its medicinal properties, is used in the form of extract. It has been traditionally used in Chinese medicine to boost energy, improve stamina, and support overall health. In this study, we investigated the hepatoprotective effects of Cordyceps militaris extract powder in a liver injury model induced by hepatic fibrosis. Sprague-Dawley (SD) rats were administered Dimethylnitrosamine (DMN) to induce liver injury, and the hepatoprotective effects of Cordyceps militaris extract powder intake were assessed by comparing changes in liver enzyme levels and histological observations. Rats injected with DMN were orally administered Cordyceps militaris extract powder at doses of 0, 125, 250, and 500 mg·kg^-1·day^-1 for three weeks. After three weeks of treatment, no significant differences were observed in hematological, clinical chemical, organ weight, gross examination, or microscopic examination between the DMN-alone group and the Cordyceps militaris extract powder-treated group. In conclusion, hepatoprotective effects against DMN-induced liver injury in SD rats treated with Cordyceps militaris extract powder were not observed under this study condition.

• The Korean Journal of Financial Management
• /
• v.25 no.1
• /
• pp.51-84
• /
• 2008

We investigate the signaling effect of repurchase preceding new equity issue using Korean data. In a short time span, firms announce stock repurchases and equity offerings. The proximity of two events in Korean firms indicates that those are not independent of each other. In this paper, we test the signaling effect of repurchase on equity offerings on the two measures. One is announcement effect, which is measured as CAR(0, +2). The other is the effectiveness which is measured as CAR(0, +30) because the price movement during this window influences on the price of new issues. Previous studies that stock repurchase convey positive signal to equity offerings-Billet and Xue(2004) and Jung(2004)-construct sample without the limit of time interval between two events. This causes the unclear relation between those because of the long time interval. In this study we consider only samples of being within one year each other to reduce this problem and clarify the signal of repurchase on equity offerings. Korean firms are allowed to repurchase own shares with two different method. One is direct repurchase as same as open market repurchase. The other is stock stabilization fund and stock trust fund which trust company or bank buy and sell their shares on the behalf of firms. Generally, the striking different characteristic between direct repurchase and indirect repurchase is following. Direct repurchase is applied by more strict regulation than indirect repurchase. Therefore, the direct repurchase is more informative signal to the equity offering than the indirect repurchase. We construct two sample firms- firms with direct repurchase preceding-equity offerings and indirect repurchase-preceding equity offering, and one control firms-equity offerings only firms-to investigate the announcement effect and the effectiveness of repurchases. Our findings are as follows. Direct repurchase favorably affect the price of new issues favorably. CAR(0, +2) of firms with direct repurchase is not different from that of equity offerings only firms but CAR(0, +30) is higher than that of equity offerings only firms. For firms with indirect repurchase and equity offerings, Both the announcement effect and the effectiveness does not exist. Jung(2004) suggest the possibilities of how indirect stock repurchase can be regarded as one of unfair trading practices on based on the survey results that financial managers of some of KSE listed firms have been asked of their opinion on the likelihood of the stock repurchase being used in unfair trading. This is not objective empirical evidence but opinion of financial managers. To investigate whether firms announce false signal before equity offerings to boost the price of new issues, we calculate the long-run performance following equity offerings. If firms have announced repurchase to boost the price of new issues intentionally, they would undergo the severe underperformance. The empirical results do not show the severer underperformance of both sample firms than equity offerings only firms. The suggestion of false signaling of repurchase preceding equity offerings is not supported by our evidence.

• Radiation Oncology Journal
• /
• v.12 no.2
• /
• pp.233-241
• /
• 1994

Purpose : This study was performed to verify dose distribution with the tissue compensator which is used for uniform dose distribution in total body irradiation(TBI). Materials and methods : The compensators were made of lead(0.8mm thickness) and aluminum(1mm or 5mm thickness) plates. The humanoid phantom of adult size was made of paraffin as a real treatment position for bilateral total body technique. The humanoid phantom was set at 360cm of source-axis distance(SAD) and irradiated with geographical field size(FS) $144{\times}144cm^2(40{\times}40cm^2$ at SAD 100cm) which covered the entire phantom. Irradiation was done with 10MV X-ray(CLINAC 1800, Varian Co., USA) of linear accelerator set at Department of Therapeutic Radiology, Chonnam University Hospital. The midline absorbed dose was checked at the various regions such as head, mouth, mid-neck, sternal notch, mid-mediastinum, xiphoid, umbilicus, pelvis, knee and ankle with or without compensator, respectively. We used exposure/exposure rate meter(model 192, Capintec Inc., USA) with ionization chamber(PR 05) for dosimetry, For the dosimetry of thorax region TLD rods of $1x1x6mm^3$ in volume(LiF, Harshaw Co., Netherland) was used at the commercially available humanoid phantom. Results : The absorbed dose of each point without tissue compensator revealed significant difference(from $-11.8\%\;to\;21.1\%$) compared with the umbilicus dose which is a dose prescription point in TBI. The absorbed dose without compensator at sternal notch including shoulder was $11.8\%$ less than the dose of umbilicus. With lead compensator the absorbed doses ranged from $+1.3\%\;to\;-5.3\%$ except mid-neck which revealed over-compensation($-7.9\%$). In case of aluminum compensator the absorbed doses were measured with less difference(from $-2.6{\%}\;to\;5.3\%$) compared with umbilicus dose. Conclusion : Both of lead and aluminum compensators applied to the skull or lower leg revealed a good compensation effect. It was recognized that boost irradiation or choosing reference point of dose prescription at sternal notch according to the lateral thickness of patient in TBI should be considered.

• Journal of Distribution Science
• /
• v.9 no.4
• /
• pp.93-102
• /
• 2011

With the increasing interest in boosting conventional markets, many authors have paid considerable attention to the roles of shop owners, store image improvement, and how to attract or maintain customers. Nevertheless, it is not easy to find papers related to the relationship between shop owners and their contribution to trading areas, directly or indirectly, in the academic world. Accordingly, research for answering the following question has been initiated: what kind of roles do shopkeepers should play in revitalizing poor conventional markets? Based on the previous studies focusing on enhancing traditional markets, this research was approached from the new insights that have been obtained concerning how to boost conventional markets, that is, from the perspectives of a shop owner and a trader. Therefore, this research aims at identifying some resolutions associated with the roles of shop owners to enhance a shopping district in a specific area, classifying their business roles into a few categories, depending on the degree of their participation in improving the shopping environment. Compared with previous studies focusing on emphasizing the importance of improving customer services from a shopkeeper's perspective, this research provides a new insight as far as how to boost conventional markets. It is, furthermore, necessary to note how market participants, particularly shop owners as they are the key players, can contribute to rebuilding their business area together with their customers. As a research technique for effectively achieving the research goal, the authors adopted a documentation methodology based on a large amount of the existing literature for studying how to rebuild traditional markets. Concerned about the ways to revitalize conventional markets, many authors have proposed a variety of strategies, and have suggested more detailed action plans from a practitioner's perspective. By analyzing these research results, the authors will have accomplished the research aim. Rather than simply identifying the roles of shop owners, the author found that they had to understand their social contribution for enhancing their trading areas, as well as their functional roles, in forming a regional society. The conventional market should be, thus, regarded as the place to share regional culture. Consequently, the authors draw some conclusions from the research results. In order to answer the above question, it was found that the roles of shop owners have been considered as one of the most important ways for revitalizing traditional markets. With respect to their roles, it is evident that their business activities are closely related to the improvement of the trading area in terms of sociality, regional development, and market revitalization, by selling products or services to the customers visiting that area. In a word, this implies that shop owners have to actively take part in boosting conventional markets as a core player. Although the authors have properly achieved the research aim, this study has a limitation, like most other research, in adopting a documentation method. Because the research is based on existing data results provided by the prior research conducted a long time ago, whether the research findings are applicable in a contemporary market should be re-examined in future research from a practitioner's perspective, rather than from an academic's perspective.

• Korean Journal of Microbiology
• /
• v.45 no.2
• /
• pp.91-98
• /
• 2009

Infectious bursal disease (IBD) caused by the infectious bursal disease virus (IBDV) has an important economic impact on the poultry industry worldwide. This study examined the adjuvant effects of a plasmid encoding chicken interleukin-6 (pcDNA-ChIL-6) and levamisole (LMS) on in ovo prime-boost vaccination using a genetic vaccine (pcDNA-VP243) to prime in chicken followed by a killed-vaccine boost. A pcDNA-VP243 was injected into the amniotic sac alone or in combination with a pcDNA-ChIL-6 or LMS at embryonation day 18, followed by an intramuscular injection of killed IBD vaccine at 1 week of age. The chicken were orally challenged with very virulent IBDV (vvIBDV) strain at 3 weeks of age and observed for 10 days. No mortality was observed in the groups that received the pcDNA-VP243 alone and pcDNA-VP243 plus pcDNA-ChIL-6 or LMS compared to 100% mortality in unvaccinated challenge control group. However, as determined by bursal damage (the presence of IBDV RNA, B/B ratio, and lesion score), a pcDNA-VP243 alone group was superior to pcDNA-VP243 plus pcDNA-ChIL-6 or LMS groups in the protection against post-challenge. These findings suggest that in ovo priming with genetic vaccine and boosting with killed vaccine is an effective strategy for protecting chicken against vvIBDV and the addition of pcDNA-ChIL-6 or LMS did not enhance protective immunity.