• 한국물환경학회지
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• 제22권1호
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• pp.1-6
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• 2006

In this study, five commercially available fouling resistant low-pressure RO membranes were investigated for the treatment of seasonally brackish surface water with high organic content (${\approx}24mg/L$). The membranes investigated are LFC-1 (Hydranautics), X20 (Trisep), BW30FR1 (FilmTec), SG (Osmonics), and BE-FR (Saehan). The results of surface characterization revealed that each of these membranes has one or two unique surface characteristics to minimize the adherence of the fouling materials to the membrane. Specifically, the LFC1 membrane features a neutral or low negative surface to minimize electrostatic interactions with charged foulants. The X20, on the other hand, shows a highly negatively charged surface, and thus, is expected to perform well with feed waters containing negatively charged organics and colloids. The BW30FR1 exhibits a relatively neutral and hydrophilic surface, which could be beneficial for lessening organic and/or biofouling. The SG membrane has a smooth surface that makes it quite resistant to fouling, particularly for colloidal deposition. Lastly, BE-FR membrane demonstrated a medium surface charge and a slightly higher hydrophobicity. In the pilot study, all of the four membranes experienced a gradual increase in MTC (water mass transfer coefficient or specific flux) over time, indicating no fouling occurred during the pilot study. The deterioration of permeate water quality such as TDS was also observed over time, suggesting that the integrity of the membranes was compromised by the monochloramine used for biofouling control.

• 동의생리병리학회지
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• 제26권6호
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• pp.886-893
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• 2012

Methicillin-Resistant Staphylococcus aureus (MRSA) is a cephalosporin and beta-lactam antibiotic-resistant strain. In most cases, MRSA is spread from infected patients and infection rates are growing increasingly. Furthermore, increased resistance to antibiotics is causing serious problems in the world. Staphylococcus aureus is responsible for both nosocomial and community-based infections that range from relatively minor skin and soft tissue infections to life-threatening systemic infections. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. In this study, we investigated antimicrobial activity of oriental medicine prescription against MRSA. The minimum inhibitory concentration (MIC) of Sohamhyung-tang water extract against S. aureus strains ranged from 500 to 2,000 ${\mu}g/mL$, so we have it confirmed that a strong antibacterial effect. Also, the combinations of Sohamhyung-tang water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Sohamhyung-tang water extract against MRSA have antibacterial activity, it has potential as alternatives to antibiotic agent. We suggest that the Sohamhyung-tang water extract lead the treatment of bacterial infection to solve the resistance and remaining side-effect problems that are the major weak points of traditional antibiotics.

• 대한의생명과학회지
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• 제30권1호
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• pp.32-35
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• 2024

In vitro antimicrobial activities of hot water extracts of Chamaecyparis obtuse, for methicillin-resistant Staphylococcus aureus (MRSA) was compared to commonly used conventional antimicrobial agents. All MRSA was susceptible to linezolid or vancomycin, but also to erythromycin. MIC range and MIC₉₀ to erythromycin, clindamycin, levofloxacin, tetracycline for MRSA were each 4 ㎍/mL, 2 ~ >128 ㎍/mL, ≤0.06 ~ >128 ㎍/mL, 0.25 ~ >128 ㎍/mL, 0.25~64 ㎍/mL and 4 ㎍/mL, .128 ㎍/mL, >128 ㎍/mL, >128 ㎍/mL, 64 ㎍/mL. The hot water extracts of leaf of C. obtuse had the lowest MIC range, MIC₅₀, and MIC₉₀ (0.125 µL/mL) for the MRSA tested, and it was possible more potent than various conventional antimicrobial agents. Screen antibacterial drug candidate with high antibacterial activity such as derivatives of C. obtuse leaf extract such as terpinen-4-ol or using combined therapy with commercialized antibacterial agents will likely be helpful in treating refractory MRSA infections.

• 접착 및 계면
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• 제7권3호
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• pp.16-25
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• 2006

내열성 및 투습방수기능을 가진 신발용 직물 및 부직포를 제조하기 위하여 스크린 방식으로 공정조건을 검토하고 투습방수 필름을 라미네이팅 한 후, 최종제품의 물성을 평가하였다. 결과는 다음과 같다. 열가소성 핫 멜트와는 달리 반응형 폴리우레탄 핫 멜트는 작업 이후에 적정한 내열성을 보유하는 것으로 나타났다. 최적의 용융접착 공정조건은 다음과 같다 ; 드럼 온도 $95^{\circ}C$, 호스 온도 $97^{\circ}C$, 공급파이프 온도 $100^{\circ}C$, 스크린 온도 $105^{\circ}C$이고, opposite roller의 압력은 $1kgf/cm^2$, laminating roller의 압력은 $3kgf/cm^2$이며, 가공속도는 15 m/min이다. 투습도는 필름의 두께가 증가함에 따라 투습도는 감소하였으나, 내수도는 증가하였고, 공기투과도는 필름의 영향이 지배적이었다.

• 한국수산과학회지
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• 제42권4호
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• pp.335-343
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• 2009

Antimicrobial resistance patterns of Vibrio species isolated from brackish water in Geoje, Tongyeong and Goseong, Gyeongsangnamdo province into which streams, sewage and leachate all flowed. Only 19 strains (10.7%) of 177 V. parahaemolyticus were susceptible to 15 antimicrobials. 146 strains (69.5%) proved resistant against more than one antimicrobial and 12 strains (6.8%) were multi-drug resistant. The resistance rate of 152 strains were 85.9% against AM and 26.6% against RA, 16.4% against AN, 13.6% against Sand 13.0% against TMP. 86 strains of 129 V. cholerae non-O1 (66.7%) were susceptible to antimicrobials and 31 strains (24.0%) were resistant to more than one antimicrobial and 12 strains (9.3%) were multi-drug resistant. The antimicrobial resistance rate of 129 strains against 15 antimicrobials, with the exception of C, CIP, E and GM, i.e. 11 antimicrobials, was 0.7-16.2%, 16.2% of 129 strains proved resistant against RA and 13.9% against AM, 9.3% against TMP, 7.7% against SXT and 6.9% against TE. 19 of 49 strains of V. mimicus (38.8%) were susceptible to antimicrobials and 31 strains (61.2%) were resistant against more than one antimicrobial; none of the strains were multi-drug resistant. 15 strains of V. mimicus were resistant against only RA, AmC and TE. The resistance rate was 59.2% against RA (highest) 4.1% against AmC and 2.0% against TE.

• 한국환경보건학회지
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• 제29권2호
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• pp.94-102
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• 2003

This study was carried out to investigated the distribution and characteristics of Vibrio spp. isolated from fish and shellfish, seawater and brackish water samples collected from Pohang, Uljin, Yeongduk and Gyeongju in Gyeongbuk Province from April 2000 to October 2000. Total 155 strains of genus Vibrio were isolated from 439 collected samples, and numbers of isolated strains of V. parahaemolyticus and V. vulnificus were 140 and 15, respectively. The isolation rate from the samples collected in Pohang was the highest as 41.5% (76 strains), and wat the highest as 71.4% (30 strains) in brackish water, and was the highest as 55.7% (34 strains) in August. And the optimal pH, temperature, and NaCl concentration for growth of V. parahaemolyticus and V. cholerae were 8.0, 3$0^{\circ}C$ and 2.0％, respectively. In a resistance test for environmental factors, heat and cold resistants of V. parahaemolyticus were higher than those of V. vulnificus, withstanding for 15 minutes at 6$0^{\circ}C$ and 6 days at -18$^{\circ}C$. The pH range for existence of V. parahaemolyticus and V. vulnificus were 4.5~l1.0 and 4.5~10.0, showing the similar resistance to pH. V. parahaemolyticus and V. vulnificus could grow in media containing up to 10.0% and 7.0% NaCl, respectively, Salt-tolerance of V. parahaemolyticus was higher than that of V. vulnificus. In an antibiotics sensitivity test against 16 strains of V. parahaemolyticus, twelve strains were resistant to ampicillin, eight strains were resistant to cephalothin. one strain was resistant to streptomycin, and one strain was resistant to ticarcillin.

• 한국환경보건학회지
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• 제40권3호
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• pp.225-233
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• 2014

Objective: This study was performed in order to investigate the distribution of antibiotic resistant E. coli and water quality in waterscape facilities. Methods: Nine waterscape facilities were selected and classified into three types: ground, wall and general fountain. The items analyzed in this study were pH, turbidity, $KMnO_4$ consumption, total colony, total coliforms, fecal coliforms and E. coli. Additionally, an antibiotic resistance test on E. coli was performed. Results: There were no sampling sites that exceeded the permitted limits of water quality, but the concentration of pollutants was high at the beginning operation in June. Moreover, concentration of turbidity, $KMnO_4$ consumption and total colony were higher in ground fountains than in wall and general fountains. Five species of antibiotic resistant E. coli were detected from three sampling sites. Conclusions: The waterscape facilities were significantly contaminated with water microorganisms, especially total colony, total coliforms and fecal coliforms. Disinfection and filtration systems to remove pollutants should be installed for safe waterscape facilities.

• 한국화재소방학회논문지
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• 제24권3호
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• pp.52-57
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• 2010

본 논문에서는 방염에 의한 초가지붕과 목재구조에 대한 화재 예방대책을 고찰하였다. 초가지붕 재료인 볏짚에 함침시간을 달리하여 방염처리를 한 후 물에 침수시켜 세척한 후에도 방염성능을 유지하는지 확인하였다. 목재는 방염처리 방법에 따른 방염효과를 비교분석하기 위하여 상압함침법과 진공가압법, 붓칠 등의 방법으로 방염처리 하였다. 볏짚의 방염성능은 콘 히터를 이용하여 착화지연시간을 측정하였으며 목재의 방염성능은 45도 연소시험과 콘 히터 실험을 통해 실험하였다. 실험 결과 특수 가연물인 볏짚의 경우 방염처리한 볏짚의 착화지연시간이 처리되지 않은 것보다 훨씬 길게 나타났으며 방염처리 후 물에 침수시켜 세척한 경우에도 처리되지 않은 시료에 비하여 착화지연시간이 길게 나타나 방염성능을 유지하는 것으로 나타났다. 목재의 경우 진공가압법으로 방염처리한 시료의 방염효과가 가장 우수하였고 붓칠이나 상압함침한 경우에도 처리하지 않은 것보다 착화지연시간이 길게 나타나 화재 확산 예방에 효과가 있음을 알 수 있었다.

• Corrosion Science and Technology
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• 제16권3호
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• pp.141-150
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• 2017

Impregnating with quality silicone water repellent on the concrete surface is an effective method of protecting concrete. Quality silicone water repellent has been widely used in the engineering profession because of its desirable properties such as hydrophobicity, keeping concrete breathable and preserving the original appearance of the concrete. The companies in China that produce silicone water repellent are listed. Test methods in the specifications or standards about silicone water repellent in China are summed. The test methods relative to durability of concrete impregnated with silicone water repellent (such as resistant to chloride ion penetration, resistant to alkali, resistance to freezing and thawing and weatherability etc.) and the constructive quality (such as water absorption rate, impregnating depth and the dry velocity coefficient etc.) are compared and analyzed. The results indicate that there are differences among test methods relative to different specifications with the same index and therefore, confusion has ensued when selecting test methods. All test methods with the exception of the method of water absorption rate by using a Karsten flask are not non-destructive methods or conducted in a laboratory. Finally, further research on silicone water repellent during application is proposed.

• 한국물환경학회지
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• 제28권6호
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• pp.911-916
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• 2012

Recently, antibiotic resistant genes (ARGs) in the environment are emerging as pollutants, since these genetic contaminants can eventually be transferred to human pathogens. The aim of this study was to develop the experimental model of antibiotic resistant gene (ARG) plasmid transfer as a function of various environmental conditions. For this purpose, the multi drug resistant plasmid pB10, which is known to be originally isolated from a wastewater treatment plant, was selected as a model transfer plasmid and Escherichia coli $DH5{\alpha}$ containing pB10 was used as a model donor. Pseudomonas aeruginosa, an opportunistic pathogen, was selected as the recipient for the conjugation experiment. When the donor and recipient were exposed to various stressors including antibiotics and heavy metal as a function of the concentrations (10, 100 and, 1000 ppb), statistically increased plasmid transfer rate was observed at a concentration of 10 ppb of tetracycline and sulfamethoxazole compared to control (no antibiotic exposure). Accordingly, the developed experimental ARG model by various stressor is a promising tool for evaluating the dissemination of ARGs by micro-contaminants in aquatic environment.