• Journal of Life Science
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• v.18 no.1
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• pp.58-62
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• 2008

A novel agar-degrading bacterium SL-12 was isolated from seashore of Kijang at Busan, Korea, and cultured in marine broth 2216 media. Isolated bacterium SL-12 was identified as Glaciecola genus by 16S rDNA sequencing with 98% identity. The optimum pH of the enzyme activity was 7.0 and the optimum temperature for the reaction was $30^{\circ}C$. The enzyme hydrolyzed neoagarohexaose to yield neoagarobiose as the main product, indicating that the enzyme is ${\beta}$-agarase. Thus, isolated bacterium and the enzyme would be useful for the industrial production of neoagarobiose.

• The Journal of Natural Sciences
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• v.14 no.2
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• pp.93-102
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• 2004

A yeast strain SL-27 found to produce active intracellular tyrosinase inhibitor was screened from 972 kinds of yeasts. It was identified as Malassezia pachydermatis based on microbiological characteristics. The optimum pH and temperature for the growth of Malassezia pachydermatis SL-27 were pH 7.0 and $37^{\circ}C$, respectively. The optimal culture conditions for the production of tyrosinase inhibitor by Malassezia pachydermatis SL-27 were investigated. The optimal medium cimposition for tyrosinase inhibitor production was determined to be 1.0% casamino acid, 2.0% glucose, 0.1% $KH_2PO_4$, 0.05% $MgSo_{4-}7H20$ and each 0.01 of $CaCl_2$ and NaCl. Optimal initial pH and temperature for the production of tyrosinase inhibitor were pH 5.0 and $30^{\circ}C$, respectively. The maximum tyrosinase inhibitory activity of 84%/mL of cell-free extract was showed after 12 h of cultivation under the optimal culturing conditions.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1116-1122
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• 2011

In this study, site-directed mutagenesis was performed on the ${\beta}$-agarase AgaA gene from Zobellia galactanivorans to improve its catalytic activity and thermostability. The activities of three mutant enzymes, S63K, C253I, and S63K-C253I, were 126% (1,757.78 U/mg), 2.4% (33.47 U/mg), and 0.57% (8.01 U/mg), respectively, relative to the wild-type ${\beta}$-agarase AgaA (1,392.61 U/mg) at $40^{\circ}C$. The stability of the mutant S63K enzyme was 125% of the wild-type up to $45^{\circ}C$, where agar is in a sol state. The mutant S63K enzyme produced 166%, 257%, and 220% more neoagarohexaose, and 230%, 427%, and 350% more neoagarotetraose than the wild-type in sol, gel, and nonmelted powder agar, respectively, at $45^{\circ}C$ over 24 h. The mutant S63K enzyme produced 50% more neoagarooligosaccharides from agar than the wild-type ${\beta}$-agarase AgaA from agarose under the same conditions. Thus, mutant S63K ${\beta}$-agarase AgaA may be useful for the production of functional neoagarooligosaccharides.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1321-1326
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• 2006

Total ginsenosides were purified and their antioxidant, antibacterial and anticancer activities were measured. The crude extracts of ginseng, which were extracted with 75% ethanol by ultrasonification method, were firstly purified on AB-8 macroporous adsorption column to remove water soluble impurities, and decolored on Amberlite IRA 900 Cl anion-exchange column. Then, they were purified on Amberlite XAD16 adsorption column to delete the non-polar impurities. Total ginsenosides contents of the purified extracts were 79.4%, 71.7% and 72.5% in cultured wild ginseng, red ginseng and white ginseng, which were significantly increased than those of crude extracts. All of the three extracts showed concentration-dependant scavenging activities against DPPH radicals, among which white ginseng showed the most powerful activity. Cultured wild ginseng roots showed strongest effect against both B. subtilis PM 125(Gram-positive) and E. coli D31 (Gram-negative) bacteria, while red ginseng and white ginseng only showed the activity against B. subtilis. According to the result of the MTT assay, ail of the three extracts inhibited the growth of U-937 human hohistiocytic lympma cell, which were significantly different (p < 0.05) when compared to the control.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1083-1086
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• 2004

Switched Network는 Shared Network 에 비해서 스니핑에 안전하다. 하지만 비교우위일뿐 절대적으로 스니핑에 안전한 것은 아니다. 이미 Switched Network 상에서 스니핑을 할 수 있는 공격툴들이 많이 소개되어 있다. 본 논문에서는 Switched Network 상에서 ARP(Address Resolution Protocol) 스푸핑을 통한 ARP 캐시 오염을 통하여 스니핑이 가능한 시나리오를 기술한다. 이러한 시나리오를 탐지하기 위한 기존의 방법은 DHCP와 같은 동적인 환경이 포함된 경우 False Positive 를 자주 발생시키기 때문에 문제가 된다. 여기에서는 이러한 False Positive를 줄인 탐지 방법을 제시하고자 한다.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.124-124
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• 2006

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.127-127
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• 2006

• Journal of Biomedical Engineering Research
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• v.33 no.2
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• pp.89-97
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• 2012

The purpose of this study is to develop the guideline of the physicochemical and mechanical properties evaluation for silicone gel filled breast implants. First of all, the use and development status for silicone gel filled breast implants were investigated, and then, standard and criteria about performance evaluation established by the international organizations such as ASTM, FDA guidance and ISO were examined. To evaluate the mechanical properties, data research and testing for breaking strength, elongation, tensile set, joint intensity, silicone gel cohesion, weight loss from heating, static rupture resistance, impact resistance test, fatigue test, and gel bleed were performed. On the other hand, to evaluate the physicochemical properties, volatile matter, extent of cross linking, heavy metals, and extractable were analyzed. In this study, results for general function, mechanical properties and physicochemical properties were examined and reviewed for the accordance with international standard, and objective and standardized guideline was provided.

• Journal of Biomedical Engineering Research
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• v.41 no.6
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• pp.256-263
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• 2020

The importance of quality control has been emphasized to maintain safety of patients and satisfaction of medical service with medical devices used in clinic. Accordingly, objective evaluation method and standards consistently has been brought up for demand to replace outdated medical devices in appropriate time and to maintain the quality of medical service. Though many studies made suggestions methods to determine what medical devices to be replaced first, these methods were difficult in practice for its complex evaluation criteria and long time to evaluate. Therefore, in this study, a simple evaluation method is developed to identify and prioritize medical devices that are ought to be replaced. For the development of this simple evaluation method, four major characteristics of technology, safety, finance, and user satisfaction, which are considered in clinics to evaluate medical device replacement, and 14 minor attributes are distinctively selected. Each characteristic is assessed in binary form of "YES" or "NO" to minimize its subjective nature. Using this method to evaluate sampled medical devices belonging to four different characteristics, devices are suggested to be replaced in the current financial year or in the following financial year, or re-evaluated by the end of this financial year. Such results of evaluation can amend the subjective nature of existing evaluation method and give objective standards more promptly.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.428-442
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• 2023

In this study, we have a goal to develop usability evaluation guidelines for heuristic-based artificial intelligence-based Software as a Medical Device (SaMD) in the medical field. We conducted a gap analysis between medical hardware (H/W) and non-medical software (S/W) based on ten heuristic principles. Through severity assessments, we identified 69 evaluation domains and 112 evaluation criteria aligned with the ten heuristic principles. Subsequently, we categorized each evaluation domain into five types, including user safety, data integrity, regulatory compliance, patient therapeutic effectiveness, and user convenience. We proposed usability evaluation guidelines that apply the newly derived heuristic-based Software as a Medical Device (SaMD) evaluation factors to the risk management process. In the discussion, we also have proposed the potential applications of the research findings and directions for future research. We have emphasized the importance of the judicious application of AI technology in the medical field and the evaluation of usability evaluation and offered valuable guidelines for various stakeholders, including medical device manufacturers, healthcare professionals, and regulatory authorities.