• Fisheries and Aquatic Sciences
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• 제25권2호
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• pp.76-89
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• 2022

The Lophius litulon liver was used as raw material for the extraction of fish oil via various extraction methods. The extraction rate by water extraction, potassium hydroxide (KOH) hydrolysis and protease hydrolysis were compared and the results revealed the protease hydrolysis extraction had a higher extraction rate with good protein-lipid separation as observed by optical microscope. Furthermore, subsequent experiments determined neutrase to be the best hydrolytic enzyme in terms of extraction rate and cost. The extraction conditions of neutrase hydrolysis were optimized by single-factor experiment and response surface analysis, and the optimal extraction rate was 58.40 ± 0.25% with the following conditions: enzyme concentration 2,000 IU/g, extraction time 1.0 h, liquid-solid ratio 1.95:1, extraction temperature 40.5℃ and pH 6.5. The fatty acids composition in fish oil from optimized extraction condition was composed of 19.75% saturated fatty acids and 80.25% unsaturated fatty acids. The content of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were 8.06% and 1.19%, respectively, with the ratio (6.77:1) surpassed to the recommendation in current researches (5:1). The results in this study suggest protease treatment is an efficient method for high-quality fish oil extraction from Lophius litulon liver with a satisfactory ratio of DHA and EPA.

• 동의생리병리학회지
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• 제37권2호
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• pp.25-29
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• 2023

This study was designed to establish an atopic dermatitis (AD) model using MC903 and was conducted to find out the optimal challenge concentration that can cause dermatitis symptoms enough to be experimentally verified while reducing adverse effects such as weight loss. MC903 was treated at concentrations of 2, 3, and 4 nmol/day, and evaluation of skin surface symptoms, water contents, histopathological changes, body weight changes, and spleen/body weight ratio was conducted. In addition, the expression level of thymic stromal lymphopoietin (TSLP) was also observed. In our results, MC903 induced AD skin lesions such as erythema, scab and fissure and lowered skin moisture level significantly. In addition, water holding capacities in the 3 or 4 nmol groups were diminished significantly compared to that in the control group. On the other hand, 4 nmol treatment induced a weight loss of up to 20% compared to control group. Finally, a higher level of TSLP expression was observed in the 3 nmol group than in the 2 nmol group or the 4 nmol group. Taken together, we propose a total 14-day protocol consisting of 3 days of sensitization (2 nmol/day) and 6 days of challenge (3 nmol/day).

• 청정기술
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• 제15권3호
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• pp.165-171
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• 2009

본 연구에서는 전자산업에서 주로 사용되는 invar 강판재료를 식각한 후 생성되는 $FeCl_2$을 $FeCl_3$로 환원하여 회수한 후 재사용하기 위한 식각액 재생공정에서 $FeCl_3$의 회수 농도와 재생공정의 단수와의 관계를 규명하고 원하는 $FeCl_3$ 회수 농도를 얻기 위한 공정의 최적단수를 얻어낼 수 있는 simulation program을 개발하였다. 이 프로그램을 위한 여러 가지 parameter는 pilot 실험을 통해 얻었다. 개발된 프로그램에 의한 공정 모사는 폐액의 발생량 및 처리비용을 극소화할 수 있다. 또한 개발된 프로그램은 원하는 $FeCl_3$의 농도를 얻기 위한 식각액 재생시스템의 최적단수와 공정시간을 계산할 수 있다. 개발된 프로그램은 실제 전자산업에서 식각액 재생 장치의 최적 용량 산정과 식각액 회수 시스템 최적단수 계산에 활용되었다.

• 한국재료학회지
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• 제33권3호
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• pp.106-114
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• 2023

The carbon concentration in the carburized steels was measured by electron probe microanalysis (EPMA) for a range of soluted carbon content in austenite from 0.1 to 1.2 wt%. This study demonstrates the problems in carbon quantitative analysis using the existing calibration curve derived from pure iron (0.008 wt%C) and graphite (99.98 wt%C) as standard specimens. In order to derive an improved calibration curve, carbon homogenization treatment was performed to produce a uniform Kα intensity in selected standard samples (AISI 8620, AISI 4140, AISI 1065, AISI 52100 steel). The trend of detection intensity was identified according to the analysis condition, such as accelerating voltage (10, 15, 30 keV), and beam current (20, 50 nA). The appropriate analysis conditions (15 keV, 20 nA) were derived. When the carbon concentration depth profile of the carburized specimen was measured for a short carburizing time using the improved calibration curve, it proved to be a more reliable and accurate analysis method compared to the conventional analysis method.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.413-420
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• 2023

Holmium-doped TiO₂ nanotubes (Ho-TNTs) were manufactured through anodization treatment and electrochemical deposition, and optimization experiments were conducted using various Holmium doping concentrations and time as variables. Surface as well as electrochemical characteristics were analyzed to study the prepared photocatalysts. Ho-TNTs were found to exist only in anatase phase through X-ray diffraction analysis. Ho-TNTs with 0.01 wt% 100 seconds shows a photocurrent density of 3.788 mA/cm² and an effective photo-conversion efficiency (PCE) of 4.30%, which is more efficient than pure TiO₂ nanotubes (pure-TNTs) (at bias potential 1.5 V vs. Hg/HgO). The photocatalytic activity of the aforementioned Ho-TNTs for hydrogen production was evaluated with the result of -29.20 µmol/h·cm².

• 한국축산식품학회지
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• 제44권1호
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• pp.146-164
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• 2024

Owing to the residual toxicity and adverse health effects of chemical preservatives, there is an increasing demand for using natural preservatives in food. Although many natural extracts have been evaluated, research on their antibacterial effects remains insufficient. Therefore, this study aimed to explore the possibility of developing Psidium guajava, Ecklonia cava, and Paeonia japonica (Makino) Miyabe & Takeda extracts as natural food preservatives. Further, the effect of mixing these extracts on microbial growth and quality was evaluated during the refrigeration of sausages. Optimal mixing ratios were determined based on the minimum inhibitory and bactericidal concentrations of each mixed extract against the Listeria monocytogenes, Salmonella spp. and Escherichia coli. D-optimal mixing design optimization tool was further used to obtain an optimum mixing ratio of Formulation 1 (F1). The antibacterial activity of F1 increased with increasing concentration, with similar activities at 0.5% and 1%. The sausages with synthetic or natural preservatives showed significantly lower lipid oxidation than those of the control and grapefruit extract-treated sausages after 4 wk of refrigeration. Total plate counts were observed only in the control and treatment groups stored for 3 wk, and no significant effect of ascorbic acid was observed. Compared to the other samples, sausages with added natural extracts showed the highest overall acceptability scores initially and after 4 wk. Therefore, similar amounts of grapefruit seed and natural extracts had the same effect on microbiological analysis and lipid rancidity during sausage storage. Hence, this mixture can serve as a potential natural preservative in meat products.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1135-1145
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• 2024

When cells are exposed to freezing temperatures, high concentrations of cryoprotective agents (CPA) prevent ice crystal formation, thus enhancing cell survival. However, high concentrations of CPAs can also cause cell toxicity. Exopolysaccharides (EPSs) from polar marine environments exhibit lower toxicity and display effects similar to traditional CPA. In this study, we sought to address these issues by i) selecting strains that produce EPS with novel cryoprotective activity, and ii) optimizing culture conditions for EPS production. Sixty-six bacteria producing mucous substances were isolated from the Ross Sea (Antarctic Ocean) using solid marine agar plates. Among them, Pseudoalteromonas sp. RosPo-2 was ultimately selected based on the rheological properties of the produced EPS (p-CY02). Cryoprotective activity experiments demonstrated that p-CY02 exhibited significantly cryoprotective activity at a concentration of 0.8% (w/v) on mammalian cells (HaCaT). This activity was further improved when combined with various concentrations of dimethyl sulfoxide (DMSO) compared to using DMSO alone. Moreover, the survival rate of HaCaT cells treated with 5% (v/v) DMSO and 0.8% (w/v) p-CY02 was measured at 87.9 ± 2.8% after freezing treatment. This suggests that p-CY02 may be developed as a more effective, less toxic, and novel non-permeating CPA. To enhance the production of EPS with cryoprotective activity, Response Surface Methodology (RSM) was implemented, resulting in a 1.64-fold increase in production of EPS with cryoprotective activity.

• The Korean journal of internal medicine
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• 제39권3호
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• pp.399-412
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• 2024

Antimicrobial stewardship programs (ASPs) can lower antibiotic use, decrease medical expenses, prevent the emergence of resistant bacteria, and enhance treatment for infectious diseases. This study summarizes the stepwise implementation and effects of ASPs in a single university-affiliated tertiary care hospital in Korea; it also presents future directions and challenges in resource-limited settings. At the study hospital, the core elements of the ASP such as leadership commitment, accountability, and operating system were established in 2000, then strengthened by the formation of the Antimicrobial Stewardship (AMS) Team in 2018. The actions of ASPs entail key components including a computerized restrictive antibiotic prescription system, prospective audit, post-prescription review through quantitative and qualitative intervention, and pharmacy-based interventions to optimize antibiotic usage. The AMS Team regularly tracked antibiotic use, the effects of interventions, and the resistance patterns of pathogens in the hospital. The reporting system was enhanced and standardized by participation in the Korea National Antimicrobial Use Analysis System, and educational efforts are ongoing. Stepwise implementation of the ASP and the efforts of the AMS Team have led to a substantial reduction in the overall consumption of antibiotics, particularly regarding injectables, and optimization of antibiotic use. Our experience highlights the importance of leadership, accountability, institution-specific interventions, and the AMS Team.

• 대한치과기공학회지
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• 제46권3호
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• pp.84-92
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• 2024

Purpose: To evaluate the effect of post-curing on the three-dimensional (3D) accuracy of artificial teeth, denture bases, and denture base monoblock manufactured using digital light processing (DLP) technology. Methods: Using an edentulous model, a 3D design was made for complete dentures. Three groups were printed by DLP: artificial teeth, denture bases, and denture base monoblock. The models were scanned, subjected to post-curing, and scanned again. Three-dimensional analysis was performed based on the post-treatment differences among the three groups. Statistical analysis was performed using SPSS Statistics ver. 22.0 (IBM), and the Mann-Whitney U-test and Kruskal-Wallis test were employed as nonparametric tests. Results: The complete denture monoblock (CM) and complete denture artificial teeth (CA) groups showed the lowest and highest errors at 15.13 and 23.37 ㎛, respectively. The groups did not show significant differences (p>0.05). In the significance test among the three groups, no significance was found in the CA group; however, significant differences were found between the complete denture base (CB) and CM groups. In addition, the three groups showed significant differences (p<0.05). Conclusion: Although deformation may occur during the post-curing process, it is within the clinically acceptable range. Future comparative studies using different 3D printers and searching for ways to minimize errors through optimization of the post-curing process are warranted.

• Journal of Trauma and Injury
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• 제37권3호
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• pp.182-191
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• 2024

Purpose: Vascular injuries require immediate surgical treatment with standard vascular techniques. We aimed to identify pitfalls in vascular surgery for trauma team optimization and to suggest recommendations for trauma and vascular surgeons. Methods: We reviewed 28 victims and analyzed the patterns of injuries, methods of repair, and outcomes. Results: Ten patients had torso injuries, among whom three thoracic aorta injuries were repaired with thoracic endovascular aortic repair, one left hepatic artery pseudoaneurysm with embolization, and two inferior vena cava with venorrhaphy, three iliac arteries with patch angioplasty or embolization, and three common femoral arteries with bypass surgery or arterioplasty. Four patients had upper extremity injuries, among whom one brachial artery and vein was repaired with bypass surgery after temporary intravascular shunt perfusion, two radial arteries were repaired with anastomoses, and one ulnar artery was repaired with ligation. One radial artery under tension was occluded. Fourteen patients had lower extremity injuries, among whom one superficial femoral artery and vein was repaired with bypass and concomitant ligation of the deep femoral artery and vein, three superficial femoral arteries were repaired with bypass (two concomitant femoral veins with bypass or anastomosis), one deep femoral artery with embolization, two popliteal arteries with bypass or anastomosis, four infrapopliteal transected arteries, one arteriovenous fistula with ligation, and one pseudoaneurysm with bypass. However, one superficial femoral artery and all femoral veins were occluded. One leg replantation failed. Conclusions: There are potential complications of vascular access during resuscitative endovascular balloon occlusion of the aorta procedures. Vascular repair should be performed without tension or spasm. Preservation of the harvested vein in papaverine solution and blood while using a temporary intravascular shunt is a method of eliminating spasms.