• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.577-584
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• 2016

The objectives of this study were I) to compare the acid resistance (AR) of seven non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups, including O26, O45, O103, O111, O121, O145, and O157:H7 STEC isolated from various sources, in 400 mM acetic acid solution (AAS) at pH 3.2 and $30^{\circ}C$ for 25 min with or without glutamic acid and II) to determine strain survival upon exposure to simulated gastric fluid (SGF, pH 1.5) at $37^{\circ}C$ for 2 h after acid adaptation in apple, pineapple, orange, and strawberry juices at pH 3.8, $4^{\circ}C$ and $20^{\circ}C$. Results show that the O111 serogroup strains had the strongest AR (0.12 log reduction CFU/mL) which was very similar to that of O157:H7 STEC (P>0.05), compared to other serogroups in AAS without glutamic acid, whereas O26 serogroup strains showed the most sensitive AR. However, there was no significant (P>0.05) difference of AR among seven serogroups in AAS with glutamic acid. In the SGF study, 05-6545 (O45:H2), 08023 (O121:H19), and 03-4669 (O145:NM) strains adapted in fruit juices at $4^{\circ}C$ and $20^{\circ}C$ displayed enhanced survival with exposure to SGF for 60 min compared to 06E0218 (O157:H7) strains (P<0.05). In addition, 4 STEC strains adapted in pineapple juice at $4^{\circ}C$ showed enhanced survival with exposure to SGF for 60 min compared to those strains acid-adapted in the other fruit juices. Generally, adaptation at $4^{\circ}C$ in fruit juices resulted in significantly enhanced survival levels compared to acid-adapted at $20^{\circ}C$ and non-adapted conditions. The AR caused by adaptation in fruit juices at low temperature may thus increase survival of non-O157 STEC strain in acidic environments such as the gastrointestinal tract. These results suggest that more careful strategies should be provided to protect against risk of foodborne illness by non-O157 STEC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.730-742
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• 2014

In the case of On-demand routing protocol in cognitive radio ad-hoc networks, broadcasting of control packets may occur common control channel overload and packet collisions during the routing procedure. This situation is to increase the overhead of path finding and also limited to find the accurate and reliable path. Since reliable channel and path finding is restricted, path life time is shorten and path reliability is reduced. In this paper, we propose a new routing algorithm that reduces control channel overhead and increases path life time by considering the probability of appearance of primary user and channel status of neighbor nodes. Each node performs periodic local sensing to detect primary user signal and to derive primary user activity patterns. The probability of primary appearance on the current channel and the channel status can be obtained based on the periodic sensing. In addition, each node identifies the quality of the channel by message exchange through a common channel with neighbor nodes, then determines Link_Levels with neighbor nodes. In the proposed method, the Link Level condition reduces the number of control messages that are generated during the route discovery process. The proposed method can improve path life time by choosing a path through Path_Reliability in which stability and quality are weighted depending on the location. Through simulation, we show that our proposed algorithm reduces packet collisions and increases path life time in comparison with the traditional algorithm.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.404-413
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• 2011

It is important to assess and improve the warship survivability for the weapon threats which have a critical effect on warship. The survivability of the warship is defined as the capability of a warship to avoid or withstand a man-made hostile environment. The survivability of the warship consists of three categories (Susceptibility, Vulnerability and Recoverability). Firstly, the susceptibility is defined as the inability of a warship to avoid radars, guns, missiles and etc. Secondly, the vulnerability is defined as the inability of a warship to withstand the man-made hostile environment. Finally, the recoverability is defined as the ability of a warship to recover the damaged components and systems. Among them, this paper has described the vulnerability assessment for the hypothetical system which is composed of critical components. Also, the procedure which is suggested to calculate the vulnerable probability of the damaged warship is based on the Vulnerable Area Method.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.3
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• pp.274-280
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• 2018

This paper deals with the calculation of vulnerable areas of critical components required for the assessment of naval ship's vulnerability. Taking into account the effectiveness of threatening weapons, the probability density function of damage was used to assess vulnerable areas or vulnerabilities of critical components. It is shown that the vulnerable area of critical component can be simply computed from the damage function. Considering the weapon effectiveness of fragmentation and explosion on the target, both Carleton Damage Function and Rectangular Cookie Cutter Function representing the probability of damage are applied to the vulnerable area assessment. Carleton damage function is utilized to describe the weapon-target interaction in the vulnerability analyses. A problem of blast effect against an assumed naval ship is chosen as a case study. Vulnerability is evaluated by applying the suggested method to the equipments arranged in the engine room of the virtual ship.

• Food Science and Preservation
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• v.30 no.6
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• pp.1095-1106
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• 2023

This study investigated the anti-oxidative and anti-inflammatory effects of Aster glehni (AG) extract in RAW 264.7 cells and Caenorhabditis elegans. The total polyphenol and flavonoid contents were higher in the ethanol extracts than in the hot water extracts. As a result of measuring the moisture contents (%) and extraction yields (%) of AG and drying A. glehni for processing (DAG), 70% ethanol, which has the highest percentage of extraction yield, was selected as the final solvent. DPPH radical scavenging activity showed higher antioxidant activity of ethanol extracts of DAG than AG. The cytotoxicity assay of the AG or DAG ethanol extracts was treated at different concentrations (25, 50, and 100 ㎍/mL), and cell viability rates were higher than 80% at all concentrations. The LPS-stimulated nitric oxide (NO) production in RAW 264.7 was significantly reduced at all concentrations of AG and DAG groups. As a result of measuring the gene expression of iNOS, which induces NO production, the AG or DAG group decreased by 33% and 32%, compared with the phosphate buffer saline (PBS) group. Under inflammatory stress conditions, the survival rate of C. elegans treated with AG or DAG ethanol extract with LPS showed concentration-dependent improvement in survival rate compared with the PBS group. Considering these results, AG could potentially be developed as an antioxidant and anti-inflammatory functional food material.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.506-512
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• 2000

건조 농산물을 비롯한 식품에 대한 방사선 조사가 허가, 시행되고 있으며, 그 적용 범위도 확대되고 있다. 이에 따라 건조 생약재의 위생화의 대체방법으로 방사선 조사 기술의 적용이 산업계로부터 요구되고 있다. 본 연구는 감마선 조사 생약재의 효능 변화 유무를 확인하기 위한 일환으로 수행되었다. 저자 등은 사물탕, 보중익기탕 및 삼령백출산 등이 방사선 방호 효과를 보이는 것으로 이미 보고한 바 있다. 본 실험에서는 감마선 조사(10 kGy)한 이들 한약제 각각의 방사선 방호 효과를 비조사 시료와 비교 평가하였다. 효과평가를 위하여 방사선 조사 마우스에서 소장움 생존시험, 내재성 비장집락 형성시험 및 apoptosis 측정을 시행하였다. 각 한약제의 감마선 조사 시료는 3가지 시험 모두에서 비조사 시료와 유사한 효과를 나타내었으며(p<0.05), 생체내 독성도 나타내지 않았다. 이는 생약재의 여러 가지 고유 효능 중 일부의 안정성으르 확인한 것으로 생각되며, 이 결과로 미루어 보아 감마선 조사 생약재의 효능 안정성은 한의학적 고유의 효능 비교 평가를 통하여 확인될 수 있을 것으로 사료된다. 한편, 저자 등은 감마선 조사 생약재의 유효성분 안정성 및 유전 독성학적 안전성을 확인하여 보고한 바 있다. 이들 결과를 토대로 향후 감마선 조사 행약재의 고유 효능의 안정성에 관한 체계적인 연구결과를 얻는다면 생약재의 위생화 수단으로 감마선 조사기술의 이용이 실용화될 수 있을 것으로 사료된다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.1153-1165
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• 2019

Recently, threats of hacking have been increasing on the national intelligence service network and key infrastructure, including the defense field. The defense information system responds to threats from the outside through the network separation, but if the defense information system is hacked, it has a serious impact on the operations of wartime or peacetime military forces. Today, cyberattacks and threats are rising to unpredictable levels and making it practically impossible to completely block and prevent hacking threats completly. So, in this study proposed a maturity model to assess the level of cyber-resilience, which is the ability to ensure the system's viability and maintain continuity through rapid response and recovery if signs of cyberattacks by the defense information system are expected or occurred. The proposed maturity model is expected to contribute to improving the cyber security level of the defense information system by assessing the level of cyber resilience of the defense information system and identifying and supplementing fields that are lacking.

• Journal of Aquaculture
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• v.13 no.4
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• pp.303-308
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• 2000

Effects of the sediments on water quality, and the consequent survival and growth of cultured fleshy prawns, Penaeus chil1ensis were determined under selected sediment types for 6 weeks. Dissolved oxygen was 5.1-5.9 mgll in both the sediments containing sand alone, and soft sand (50%) and mud (50%). It decreased to 4.6 mgll in the mud after 6 weeks. Nitrite, ammonia and hydrogen sulfide of the seawater were 0.07-0.12, 0.16-0.29 and 0.009~0.014 mgll in both the sediments containing sand alone, and soft sand (50%) and mud (50%). The values, however, increased to 0.15, 0.36 and 0.018 mgll in the mud sediment, respectively. Survival of the prawn was below 60% in bare and mud sediments. It was above 70% in both the sediments containing sand alone, and soft sand (50%) and mud (50%). Growth and food efficiency of the prawn were significantly lower in the 100 % sand than in the sediment containing soft sand (50%) and mud (50%).

• Journal of Veterinary Clinics
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• v.28 no.6
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• pp.571-575
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• 2011

Sperm cryopreservation methods have been improved over the last few decades. However, an optimized thawing rate has not yet been established. Therefore, we investigated the effect of thawing rate on sperm function after cryopreservation. The ejaculates collected from beagle dogs were cryopreserved and then thawed at two different thawing rates ($37^{\circ}C$ for 1 min or $70^{\circ}C$ for 15 sec). The thawed sperm were evaluated for motility, viability, morphology, plasma membrane integrity, phosphatidylserine (PS) translocation, and intracellular $H_2O_2$ level. The sperm thawed rapidly at $70^{\circ}C$ showed improved motility, viability, normal morphology, plasma-membrane integrity and non-PS translocation compared to the sperm thawed slowly at $37^{\circ}C$ (P < 0.05). However, the intracellular $H_2O_2$ levels were not significantly different between the rapid- and slow-thawed sperm (P > 0.05). In conclusion, sperm rapid thawing at $70^{\circ}C$ could improve the function of cryopreserved canine sperm, and the appropriate thawing rate would enhance the quality of the cryopreserved sperm.

• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.390-398
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• 2021

In this study, the toxicity of chlorothalonil was investigated using survival rate and population growth rate of a marine rotifer, Brachionus plicatilis, typically used in live food in marine aquaculture systems. The survival rate of B. plicatilis was determined after 24 h of exposure to chlorothalonil (0.010-0.156 mg L^-1). Population growth rate of B. plicatilis was calculated after 72 h of exposure to chlorothalonil (0.078-1.250 mg L^-1). The survival rate and population growth rate of B. plicatilis exposed to chlorothalonil in single-dose toxicity assessment showed concentration-dependent reductions. Survival rates of B. plicatilis exposed to chlorothalonil had the following values: NOEC, 0.020mg L^-1; LOEC, 0.039 mg L^-1; and EC₅₀, 0.057 mg L^-1. Population growth rate of B. plicatilis exposed to chlorothalonil had the following values: NOEC, 0.156 mg L^-1; LOEC, 0.313 mg L^-1; and EC₅₀, 0.506 mg L^-1. When the residual concentration of chlorothalonil in the marine coastal area was more than 0.039 mg L^-1, it had a toxic effect on B. plicatilis, a zooplankton. This paper provides toxicity values that can be used as baseline data for organizing environmental standards of chlorothalonil. It also provides insight into toxic effects of chlorothalonil on other non-target organisms.