Inactivation efficiency of plasmid-encoded antibiotic resistance genes during water treatment with chlorine, UV, and UV/H₂O₂

Yoon, Younggun,Chung, Hay Jung,Wen Di, Doris Yoong,Dodd, Michael C.,Hur, Hor-Gil,Lee, Yunho Pergamon Press 2017 Water research Vol.123 No.-

<P><B>Abstract</B></P> <P>This study assessed the inactivation efficiency of plasmid-encoded antibiotic resistance genes (ARGs) both in extracellular form (e-ARG) and present within <I>Escherichia coli</I> (intracellular form, i-ARG) during water treatment with chlorine, UV (254 nm), and UV/H<SUB>2</SUB>O<SUB>2</SUB>. A quantitative real-time PCR (qPCR) method was used to quantify the ARG damage to <I>amp</I> <SUP> <I>R</I> </SUP> (850 bp) and <I>kan</I> <SUP> <I>R</I> </SUP> (806 bp) amplicons, both of which are located in the pUC4K plasmid. The plate count and flow cytometry methods were also used to determine the bacterial inactivation parameters, such as culturability and membrane damage, respectively. In the first part of the study, the kinetics of <I>E. coli</I> inactivation and ARG damage were determined in phosphate buffered solutions. The ARG damage occurred much more slowly than <I>E. coli</I> inactivation in all cases. To achieve 4-log reduction of ARG concentration at pH 7, the required chlorine exposure and UV fluence were 33–72 (mg × min)/L for chlorine and 50–130 mJ/cm<SUP>2</SUP> for UV and UV/H<SUB>2</SUB>O<SUB>2</SUB>. After increasing pH from 7 to 8, the rates of ARG damage decreased for chlorine, while they did not vary for UV and UV/H<SUB>2</SUB>O<SUB>2</SUB>. The i-ARGs mostly showed lower rates of damage compared to the e-ARGs due to the protective roles of cellular components against oxidants and UV. The contribution of OH radicals to i-ARG damage was negligible in UV/H<SUB>2</SUB>O<SUB>2</SUB> due to significant OH radical scavenging by cellular components. In all cases, the ARG damage rates were similar for <I>amp</I> <SUP> <I>R</I> </SUP> versus <I>kan</I> <SUP> <I>R</I> </SUP>, except for the chlorination of e-ARGs, in which the damage to <I>amp</I> <SUP> <I>R</I> </SUP> occurred faster than that to <I>kan</I> <SUP> <I>R</I> </SUP>. Chlorine and UV dose-dependent ARG inactivation levels determined in a wastewater effluent matrix could be reasonably explained by the kinetic data obtained from the phosphate buffered solutions and the expected oxidant (chlorine and OH radicals) demands by water matrix components. These results can be useful in optimizing chlorine and UV-based disinfection systems to achieve ARG inactivation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Inactivation kinetics of ARB, e- and i-ARGs by chlorine, UV, UV/H<SUB>2</SUB>O<SUB>2</SUB> were determined. </LI> <LI> Damages of ARGs occurred much more slowly than the inactivation of ARB (<I>E. coli</I>). </LI> <LI> Damages of i-ARGs were slower than e-ARGs due to protections by cellular components. </LI> <LI> 4-log ARG reductions require 40–70 (mg × min)/L for chlorine and 50–130 mJ/cm<SUP>2</SUP> for UV. </LI> <LI> ARG removals in a wastewater effluent were predictable from the ARG damage kinetics. </LI> </UL> </P>

한강물로부터 분리된 방사선 내성 세균들의 계통학적 다양성 및 UV 내성 분석

이재진,주은선,이도희,정희영,김명겸,Lee, Jae-Jin,Joo, Eun Sun,Lee, Do Hee,Jung, Hee-Young,Kim, Myung Kyum 한국미생물학회 2016 미생물학회지 Vol.52 No.1

이 논문은 서울 한강물에서 분리한 방사선 내성 세균군집과 분리된 신종 세균의 UV 내성 특성에 관한 내용이다. 세균은 R2A agar와 1/10 R2A agar를 사용하여 3 kGy가 조사된 한강물에서 분리되었다. 그 결과 방사선에 내성을 가지는 것으로 추측되는 균주를 60주 분리하였고, 본 연구 분석 자료로 사용하였다. 16S rRNA 유전자 염기서열 분석을 통해 분리균주 60개의 계통수를 파악한 결과, 3개의 문(4개의 속)이 확인되었고, Deinococcus-Thermus (Deinococcus)가 61.7%, Firmicutes(Exiguobacterium)는 15%, Bacteroidetes (Hymenobacter, Spirosoma)는 23.4%의 비중을 나타냈다. 분리균주 중 29개 균주가 Deinococcus, Hymenobacter, Spirosoma에 속하는 신종 또는 다른 신속으로 분류될 가능성을 보였으며, 앞으로 추가적인 신종 실험이 진행될 예정이다. 그리고 신종 예상균주를 9개 선정하여 UV 내성 실험을 진행한 결과, 9개 균주 모두 D. radiodurans $R1^T$ 균주 만큼 높은 UV 내성을 가지는 것으로 나타났다. 또한 분리된 Firmicutes (Exiguobacterium) 균주는 아직까지 방사선 내성 연구 보고가 되어 있지 않아서 추가적인 방사선 내성 연구가 필요하다. The aim of this study was to investigate the UV-resistance of radiation-resistant bacteria isolated from the water of Han River, South Korea. The water sample was irradiated with 3 kGy gamma radiation prior to isolation. Radiation-resistant bacterial strains were isolated by standard serial dilution method on R2A and 1/10 diluted R2A agar. The resulting purely isolated 60 cultures of bacteria were analysed for UV resistance and used in further studies. Based on the comparative analyses of 16S rRNA gene sequences, the bacterial isolates were divided into 3 phyla (4 genera): the phylum Deinococcus-Thermus (the genus Deinococcus) was 61.7%, Bacteroidetes (Hymenobacter and Spirosoma) was 23.4%, and Firmicutes (Exiguobacterium) was 15%. The results suggested that twenty-nine isolates are candidates new species belonging to Deinococcus, Hymenobacter, and Spirosoma, or other new genera. Nine bacterial strains were selected among the novel candidates and the UV-resistance analysis was conducted. All the candidate bacterial strains showed high UV resistance, similar to that of D. radiodurans R1.

폴리(비닐리덴 플루오라이드)(PVDF) 막 위에 코팅되는 플루오로에틸렌 비닐 에테르(FEVE) 막의 가교형태에 따른 내자외선성 및 물성 변화 연구

김진오(Jin-O Kim),심소라(Sora Sim),조은범(Eun-Bum Cho) 한국고분자학회 2017 폴리머 Vol.41 No.2

본 연구에서는 코일 코팅용 폴리(비닐리덴 플루오라이드)(poly(vinylidene fluoride), PVDF) 막 위에 코팅된 플루오로 에틸렌 비닐 에테르(fluoroethylene vinyl ether; FEVE) 코팅 층의 가교형태에 따른 화학적, 물리적 특성 및 내자외선성을 고찰하였다. 고광택 투명 FEVE 층의 가교제로서 멜라민 류의 hexamethoxymethylmelamine(HMMM)과 이소시아네이트 류의 hexamethylene diisocyanate(HDI)를 각각 사용하여 가교 반응을 적용하였다. 코팅 막의 기계적 물성 및 내자외선성(UV-B) 시험은 미국재료시험협회 규격(ASTM)에 의거하여 진행되었다. 이소시아네이트를 사용한 우레탄 반응군이 HMMM의 멜라민 가교 반응군 대비 기계적, 화학적 강도는 일부 상대적 열위이나 내자외선성(UV-B)에서는 우수한 결과를 보였다. 또한 같은 HMMM의 멜라민 가교 반응이더라도 가교제 함량에 따라 내자외선성이 변화되는 모습이 관찰되었다. 본 연구를 통해 PVDF 막 위의 FEVE 코팅에 적절한 가교 반응을 선택 설계함으로써 건축 외장재 용도로 자외선에 의한 코팅 막 열화를 최소화하면서 우수한 내후성을 확보할 수 있게 되었다. This study describes the effect of crosslinking types on chemical and physical properties and UV resistance of fluoroethylene vinyl ether (FEVE) layer over poly(vinylidene fluoride) (PVDF) in coil-coating. Hexamethoxymethylmelamine (HMMM) of melamine type and hexamethylene diisocyanate (HDI) of isocyanate type were used respectively as crosslinkers of high gloss and transparent FEVE layer on the PVDF coating layer. The evaluation of physical property and UV (UV-B) resistance was processed within ASTM standards. Urethane-reaction group using HDI showed relatively much better stability against UV (UV-B) than melamine reaction group of HMMM, while some physical and chemical resistances were found to be weaker. Also, in spite of the same melamine reaction group, the UV resistance was varied according to the ratio of HMMM cross-linker. From this study, it is expected to enhance weatherability as well as minimize the film deterioration from UV through optimizing crosslinking reaction in FEVE/PVDF double layer coating as a building exterior application.

UV Responsive Characteristics of n-Channel Schottky Barrier MOSFET with ITO as Source/Drain Contacts

( Tae Hyeon Kim ),( Chang Ju Lee ),( Dong Seok Kim ),( Sang Yun Sung ),( Young Woo Heo ),( Jung Hee Lee ),( Sung Ho Hahm ) 한국센서학회 2011 센서학회지 Vol.20 No.3

We fabricated a schottky barrier metal oxide semiconductor field effect transistor(SB-MOSFET) by applying indium-tin-oxide(ITO) to the source/drain on a highly resistive GaN layer grown on a silicon substrate. The MOSFET, with 10 μm gate length and 100 μm gate width, exhibits a threshold gate voltage of 2.7 V, and has a sub-threshold slope of 240 mV/dec taken from the I(DS)-V(GS) characteristics at a low drain voltage of 0.05 V. The maximum drain current is 18 mA/mm and the maximum transconductance is 6 mS/mm at V(DS)=3 V. We observed that the spectral photo-response characterization exhibits that the cutoff wavelength was 365 nm, and the UV/visible rejection ratio was about 130 at V(DS)=5 V. The MOSFET-type UV detector using ITO, has a high UV photo-responsivity and so is highly applicable to the UV image sensors.

UV를 적용한 역삼투막의 실란-에폭시 표면 개질 및 특성 평가

박희민,양원용,이용택 한국막학회 2018 멤브레인 Vol.28 No.3

본 연구는 역삼투막의 물리-화학적 표면 개질을 통하여 친수성 증가에 따른 내오염성 및 내염소성을 향상하고자 하였다. 자외선조사로 상용막 표면을 활성화한 후 실란 커플링제를 sol-gel법으로 개질하여 염소에 대한 민감도를 낮춰 폴리 아마이드 활성층을 보호하여 내염소성을 향상시켰다. 또한, 에폭사이드의 개수가 다른 PGPE, SPE 두 종류의 에폭시로 코팅 후 에폭사이드의 개환반응으로 내오염성을 향상시켰으며, 표면 개질 조건은 접촉각과 FT-IR, XPS 분석을 통해 최적화하였다. 실란-에폭시 개질막의 오염성 평가 결과 투과도 감소율이 상용막보다 약 1.5배 감소하였고, 내염소성 평가 결과 20,000 ppm × hr에서도 염제거율이 90% 이상 유지되었다. The purposes of this paper were to improve both fouling and chlorine resistance by increasing the hydrophilicity of the reverse osmosis membrane. In order to improve chlorine resistance, the surface of RO membrane was activated by ultraviolet irradiation, and then it was modified by the sol-gel method using Octyltriethoxysilane (OcTES) such as the silane coupling agent to low sensitivity to chlorine, thereby the polyamide active layer was protected and chlorine resistance was improved. In addition, polyglycerol polyglycidyl ether (PGPE) and sorbitol polyglycidyl ether (SPE) coating with different number of epoxides, ring opening reaction of epoxide improved the anti-fouling resistance. The surface modification condition was optimized by FT-IR, XPS, and contact angle analysis. As a result, the permeability reduction rate of the silane-epoxy modified membrane after the fouling test was decreased about 1.5 times as compared with that of the commercial membrane. And the salt rejection was maintained over 90% at 20,000 ppm × hr even after chlorine resistance test.

불소 단량체를 이용한 자외선 경화형 내 오존성 코팅 막 제조

이창호 ( Chang Ho Lee ),이상구 ( Sang Goo Lii ),김성래 ( Sung Rae Kim ),이종대 ( Jong Dae Lee ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.3

The effect of synthesis conditions such as various organic material and composition of organic-inorganic material in ozone resistance and surface characteristic of ultraviolet cured organic-inorganic hybrid coating film has been investigated. Organic-inorganic hybrid coating solution was prepared using tetraethoxysilane (TEOS), silane coupling agent methacryloyloxypropyltrimethoxysilane (MPTMS), 2,2,2-trifluoroethylmethacrylate, and various organic materials with acrylate group, bar-coated on substrates using applicator and densified by UV-curing. It was found that ozone resistance and surface hardness of the coating film was increased with contents of TEOS. It was also found that ozone resistance of coating film was increased with contents of 2,2,2-trifluoroethylmethacrylate. On the other hand, surface hardness was decreased with increase of 2, 2, 2-trifluoroethylmethacrylate. In addition, Surface hardness of coating film was increased with the addition of aliphatic urethane acrylate. It was also found that the transmittance of coating films was not influenced by content of TEOS and 2, 2, 2-trifluoroethylmethacrylate. In addition, the coating film exhibited high transmittance of above 90%.

자외선 경화형 유기/무기 하이브리드에 의한 하드코팅 특성 향상

한지호 ( Ji-ho Han ),김형일 ( Hyung-il Kim ) 한국공업화학회 2017 공업화학 Vol.28 No.6

투명 플라스틱 소재를 광학용으로 적용하기 위해서는 표면경도 및 내열성과 같은 물성의 개선이 필요하다. 본 연구에서는 이러한 물성의 개선을 위하여 자외선 경화형 유기/무기 하이브리드를 합성하였다. 유기소재 안에 무기 성분이 균일하게 최적상태로 분산되도록 하기 위하여 졸-겔 반응을 기초로 하여 동시에 반응이 진행되도록 하였다. 이러한 졸-겔 반응과 빠른 자외선 경화반응을 적절히 조합하여 우레탄 아크릴레이트 유기소재 안에 무기 성분의 분산성이 향상되도록 하여 투명성이 우수한 코팅층을 형성시킬 수 있었다. 자외선 경화형 유기/무기 하이브리드의 경화도와 코팅 물성을 변화시키기 위하여 다양한 종류의 알콕시 실란을 사용하였다. 이러한 자외선 경화형 유기/무기 하이브리드 코팅에서의 무기 성분의 함량에 따라 표면 경도와 내열성을 조절할 수 있었다. Transparent plastic substrates require an improvement in properties such as surface hardness and thermal stability for optical applications. In this study, UV-curable organic/inorganic hybrids were synthesized to improve those properties. In order to make the optimum dispersion of inorganic component into the organic matrix, an in situ synthetic method was applied based on sol-gel reaction. Dispersion of the inorganic component in the organic urethane acrylate matrix was improved by using a proper combination of sol-gel reaction and fast UV-curing resulting in the formation of the transparent coating layer. Various alkoxy silanes were employed to vary both the degree of curing and coating properties of UV-curable organic/inorganic hybrids. UV-cured organic/inorganic hybrid coatings showed an improved surface hardness and thermal resistance depending on the content of inorganic component.

PVC 바닥상재용 광경화형 하드 코팅액의 제조 및 응용에 관한 연구

박보람(Park, Bo-Ram),윤현정(Yoon, Hyun-Jung),조홍(Zhao, Hong),하진욱(Ha Jin-Wook) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.9

본 연구는 건축자재로 널리 사용되는 PVC 바닥상재의 표면을 스크래치로부터 보호하기 위하여 기존에 사 용하는 광경화형 우레탄-아크릴 수지에 내마모성을 향상시킨 광경화형 하드 코팅액 개발에 관한 것이다. PVC 바닥상재용으로 사용되는 내마모성이 없는 우레탄-아크릴 수지에 AL₂O₃(Al-160SG-3), Al(OH)3(SH-8W) 및 SiO₂(KS-5000) 등 서로 다른 내마모성을 지닌 물질을 분말 형태로 수지의 양 대비 함량(wt%)을 10~30%로 변화하여 첨가한 후 링밀(Ring Mill)을 사용, 배합하여 수지의 내마모성을 향상시킨 하드 코팅액을 제조하였다. 제조한 하드 코 팅액은 코팅층의 두께조절이 가능한 코팅(Bar-coating)을 사용하여 PVC 바닥상재에 코팅 한 후 내마모성, 연필경도, 부착력, 코팅두께 등의 코팅층 표면물성을 평가하였다. 연구결과, 수지에 AL₂O₃ 분말 30%를 혼합하여 제조한 하드 코팅액이 내마모성 1등급, 연필경도 H, 부착력 100%로 가장 좋은 물성을 보였으며, 전반적으로 입자크기가 작고, 분말 함량이 많을수록 또한 코팅두께가 두꺼워 질수록 경 도 및 내마모성이 우수한 것으로 나타났다. This study is on development of UV-cured hard coating compounds which have more improved abrasion resistance than existing UV-cured urethane-acrylic resin, to prevent a surface of a widely used PVC tile as a constructive material from being scratched. To make a high abrasion resistant hard coating solution compared to UV-cured urethane-acrylic resin which has no abrasion resistance and been used for PVC tiles, we added powder substances of different abrasion resistant level, AL₂O₃(Al-160SG-3), Al(OH)3(SH-8W), SiO₂(KS-5000), etc., to the resin, changing their contents from 10% to 30% against quantities of resin, and compounded it using Ring-Mill. After coating PVC tiles with the hard coating solution using bar-coating method that can adjust a thickness, we estimated some surface properties—abrasion resistance, pencil hardness, adhesive power, thickness of coating, and so on. As a result, a hard coating solution added 30% AL₂O₃ powder to the resin had the finest surface properties—the first grade in abrasion resistance, H in pencil hardness, 100% in adhesive power, and a hard coating solution which showed excellent solidity and abrasion resistance has smaller particle size, higher powder content, and thicker coating thickness.

첨가제 도핑에 의한 나일론 6 BCF의 내광성 및 내열성 개선

조현태,이경남,Cho, Hyeon-Tae,Lee, Kyung-Nam 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.1

Effect of light and heat resisting additives on fading of a acid dye(C.I. Acid Red 361) on nylon 6 BCF and degradation of the fiber were studied. These additives were doped in the fiber as a master batch chip during spinning process to improve dye fading or fiber degradation when nylon 6 BCF was exposed under UV-irradiation and heat. The dye fading was affected by not only UV-radiation but also heat especially above $100^{\circ}C$. With applied additives the dye fading caused by UV-radiation or heat could be lowered but the effect was not remarkable. The tensile strength retention of undyed sample was higher than that of dyed sample when the fiber was exposed under UV-irradiation. Thus it is concluded that the acid dye creates active radicals more easily than fiber during exposure of UV-irradiation and acts as a photo accelerator in degradation of nylon 6 BCF. On the other hand, the tensile strength retention of undyed sample was lower than that of dyed sample when heat was applied to the fiber. This could be attributed that radicals created during fiber degradation by heat preferably attack dye molecules rather than transfer to nylon 6 fiber molecules which causes chain scissoring. Light and thermal degradation of nylon 6 BCF were greatly improved by doping with a UV-absorber, light resisting agents or heat resisting agents to the nylon 6 BCF, but it is not easy to improve dye fading. Thus new combinations of light and thermal resisting agents showing more effective to both thermal and light fading of dye are necessary for higher light fast dyeing of nylon 6 BCF.

ZnO nanoparticles-laden cellulose nanofibers-armored Pickering emulsions with improved UV protection and water resistance

이두호,박대환,신경희,Hyemin Seo,이현숙,Yeong Jin Choi,김진웅 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.96 No.-

This study introduces a new type of Pickering emulsion system with enhanced UV-blocking and water-resisting performance, in which hydrophobically modified ZnO composite cellulose nanofibers(HCNFZnO) were employed to form an oil-in-water (O/W) interface. For this, wefirst deposited ZnOnanoparticles (NPs) on CNFs by reducing the zinc precursor and subsequently grafted hexadecyl-trimethoxysilane on the ZnO NPs. We observed that the HCNFZnO favoured the formation of afibrillarysolid layer at the O/W interface, thus producing a structurally stable Pickering emulsion. The Pickeringemulsion showed synergistic UV-blocking performance when prepared with a chemical UVfilter in theoil phase. Interestingly, owing to the inter-fibrillary attraction of cellulose bodies, the HCNFZnO-armoredPickering emulsion drops adhere to each other, thus exhibiting significant resistance to repeated rinsingwith water. These results highlight that our HCNFZnO enables the development of a UV-blocking emulsionsystem with excellent water resistance without the aid of conventional emulsifiers.