• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.45-48
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• 2000

Reverse osmosis filtration(RO) system and ultrafiltration(UF) system are principally use for domestic home drinking water treatment systems. The object of this study is to make a comparison between two systems in terms of theirs abilities to remove RNA coilphage QB as an indicator of pathogenic enteroviruses. The virus removal ratio of RO system was 99.999%, which was higher than EPA virus treatment guideline(99.99%). In the course of filtration, removal ratios of sediment filter, pre-carbon filter, reverse osmosis membrane and post-carbon filter were 75.000%, 93.208%, 99.997% and 99.999%, repectively. In case of UF system, virus removal ratio was 99.708%. Removal ratios of sediment filter, pre-carbon filter, post-carbon filter and ultrafiltration membration membrane were 71.038%, 91.530%, 98.283% and 99.708%, respecively, in UF steps. Therefore, RO system is more effective than UF system in virus removal.

• Journal of fish pathology
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• v.28 no.2
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• pp.113-116
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• 2015

A $0.45-{\mu}m$ membrane filter is generally used to remove bacterial contamination during virus extraction from fish samples. However, the number of fish viruses is drastically reduced after filtration with a $0.45{\mu}m$ filter. In this study, we investigated the effect of filters on virus infectivity titer and the change in virus titer and bacterial number following different centrifugation conditions to determine a suitable procedure for virus extraction from fish samples. $10^{4.05}$ and $10^{5.05}TCID_{50}/ml$ of infectious hematopoietic necrosis virus (IHNV) and $10^{4.05}$ and $10^{4.55}TCID_{50}/ml$ of Oncorhynchus masou virus (OMV) were not detectable after filtration with two types of $0.45-{\mu}m$ filters, except the IHNV titer was reduced by about 10 fold after filter use (company A). No significant difference was found in the virus titer following centrifugation at $880{\times}g$ (30 min) or $3,500{\times}g$ (30 min), whereas IHNV and OMV titers were reduced by about 10 and 10-1000 fold by centrifugation at $14,000{\times}g$ (30 min) and $14,000{\times}g$ (10 and 30 min), respectively. A total of 97.7-99.9% Escherichia coli were eliminated by centrifugation at $880 {\times}g$ (30 min) and $3,500{\times}g$ (30 min). These results show that fish viruses were affected by filtering, even though the effect differed by virus species and filter type. Therefore, centrifugation at $3,500{\times}g$ (30 min) and use of medium with antibiotics may be useful for virus extraction along with a reduction in bacteria.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1317-1325
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• 2008

Viral safety is an important prerequisite for clinical preparations of plasma-derived pharmaceuticals. One potential way to increase the safety of therapeutic biological products is the use of a virus-retentive filter. In order to increase the viral safety of human antihemophilic factor IX, particularly in regard to non-enveloped viruses, a virus removal process using a polyvinylidene fluoride membrane filter (Viresolve NFP) has been optimized. The most critical factor affecting the filtration efficiency was operating pH and the optimum pH was 6 or 7. Flow rate increased with increasing operating pressure and temperature. Recovery yield in the optimized production-scale process was 96%. No substantial changes were observed in the physical and biochemical characteristics of the filtered factor IX in comparison with those before filtration. A 47-mm disk membrane filter was used to simulate the process performance of the production-scale cartridges and to test if it could remove several experimental model viruses for human pathogenic viruses, including human hepatitis A virus (HAV), porcine parvovirus (PPV), murine encephalomyocarditis virus (EMCV), human immunodeficiency virus type 1 (HIV), bovine viral diarrhea virus (BVDV), and bovine herpes virus (BHV). Non-enveloped viruses (HAV, PPV, and EMCV) as well as enveloped viruses (HIV, BVDV, and BHV) were completely removed during filtration. The log reduction factors achieved were $\geq$6.12 for HAV, $\geq$4.28 for PPV, $\geq$5.33 for EMCV, $\geq$5.51 for HIV, $\geq$5.17 for BVDV, and $\geq$5.75 for BHV. These results indicate that the virus filtration process successfully improved the viral safety of factor IX.

• Korean Journal of Microbiology
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• v.9 no.4
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• pp.175-178
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• 1971

Because of the cases of Japanese Encephalitis(J.E.) were reported every year in Korea. We, Dong-A Pharmaceutical Co., Ltd., produced J.E. virus vaccine, with lower price, since 1970 in order to prevent ourselves from being infected by the disease. And inoculated the J.E. virus vaccine for the children with a great success. We are going to report several questions which brought about in producing the J.E. virus vaccine by alcohol precipitation, protamine sulfate treatment method. The results obtained were as folows ; 1) In process treated with 40% alcohol, we used to ethanol made in Germany, but it was too expensive to use it. As the result which we had studied about it, we were satisfied with J.E. virus vaccine which produced with alcohol made in Korea, and then, we treated with accurate specific gravity of 40% ethanol for the precipitation of the virus. And also, we knew that it was the best method to be treated it for 3hrs, $13^{\circ}C$. 2) When we treated with protamine sulfate (0.025mg/ml), we acquired the highest potent titer, and suited into purpose for the nitrogen concentration. 3) The filtration of the purified J.E. virus vaccine, in case of millipore filter paper of large pore size was not suitable for the sterility. Therefore the pore size less than 0.8.$\mu$ (AA filter paper) in millipore filter paper was very suitable. But it seemed to be important subhects that the smaller was the pore size, the lower was the potent titer.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.140-147
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• 2004

Urokinase is an enzyme with fibrinolytic activity (plasminogen activator) isolated from fresh urine of healthy men. Viral safety is an important prerequisite for clinical preparation of the protein from urine. In order to increase the viral safety of a high purity urokinase in regard to non-enveloped viruses, a virus removal process using a novel polyvinylidene fluoride membrane filter (Viresolve NFP) has been optimized. Urokinase was able to pass through the filter with recoveries of 95% in the production scale process. No substantial changes were observed in physical and biochemical characteristics of the filtered urokinase in comparison with those of the enzyme before filtration. A 47-mm disk membrane filter was used to simulate the process performance of the production scale cartridges and tested if it could remove several experimental model viruses for human pathogenic viruses, including porcine parvovirus (PPV), human hepatitis A virus (HAV), murine encephalomyocarditis virus (EMCV), bovine viral diarrhoea virus (BVDV), and bovine herpes virus (BHV). Non-enveloped viruses (PPV, HAV, and EMCV) as well as enveloped viruses (BVDV and BHV) were completely removed during filtration. The log reduction factors achieved were $\geq$4.86 for PPV, $\geq$4.60 for HAV, $\geq$6.87 for EMCV, $\geq$4.60 for BVDV, and $\geq$5.44 for BHV. These results indicate that the virus filtration process successfully improved the viral safety of the final products.

• Membrane Journal
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• v.30 no.1
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• pp.9-20
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• 2020

Membranes are used in most processes of biopharmaceutical production. It is used for pretreatment of other processes, separation of impurities in the process, virus removal, control of products concentration and buffer solution exchange. Virus filters play an important role in ensuring product efficacy and stability because viral contamination of biopharmaceuticals for humans is a sensitive issue that is directly related to serious clinical outcomes. Virus filters typically have complex multilayer structures made of various polymers such as surface-modified PVDF, PES, CRC. Depending on the manufacturer, filters have different pore structures and shapes, such as symmetric or asymmetric, and is used in the form of pleated membrane, flat sheets or hollow fibers. Virus filters are exclusively supplied by few foreign companies such as Asahi Kasei, Millipore, Pall and Sartorius. Replacing virus filters can be time consuming and expensive, including approval from regulatory agencies through validation. As localization has become important due to Japan's recent export regulations, it is necessary to increase the degree of technical independence.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1429-1434
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• 2004

Immunoassay is one of the important analytical methods for clinical diagnoses and biochemical studies, but needs a long time, troublesome procedures and expensive reagents. In this study, therefore, we propose the micro filter chip with microbeads for immunoassay, which has pillar structures. The advantage of the proposed micro filter chip is to use simple fabrication process and cheap materials. The mold was made by the photolithography technique with Si wafer and negative photoresist SU-8. The replica was made of PDMS, bonded on the pyrex glass. The micro filter chip consists of inlet channel, filter chamber and outlet channel. HBV (Hepatitius B virus) monoclonal antibody (Ag1) labeled with biotin were immobilized onto streptavidin coated beads of 30∼50 $\mu$m size. Fluorescein isothiocyanate (FITC)-labeled HBV monoclonal antibody (Ag8) was used to detect HBsAg (Hebatitis B virus surface Antigen), and fluorescence intensity was monitored by epi-fluorescence microscope. In this study, the immune response of less than 30 min was obtained with with the use of 100 $m\ell$ of sample.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.89-96
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• 2011

The objective of this study is to evaluate reduction efficiency of various air purifiers on airborne microorganism causing air infected animal disease according to sample collection method. Collection efficiencies of MS2 virus and Pseudomonas fluorescens by biosampler was significantly higher than those by button sampler (p<0.05). Regardless of types of air purifier and sample collection method, temporal reduction efficiencies of MS2 virus and P. fluorescens compared to initial background concentration were >50% and >45% on 5 minutes, >70% and >50% on 15 minutes, >80% and >70% on 30 minutes and >90% and >75% on 60 minutes after operating air purifier, respectively. The air purifier of ionizer type showed the highest reduction efficiency on MS2 virus followed by air purifier of electronic precipitation, water filter and dry filter while the reduction efficiency of air purifier on P. fluorescens was highest in the electronic precipitation type followed by ionizer type, dry filter type and water filter type (p<0.05). Based on the results obtained from this study, temporal reduction efficiency of air purifier on MS2 virus was relatively higher than P. fluorescens.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.258-261
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• 2005

We conducted a survey on pepper virus diseases in 31 regions in Korea from November 2001 to December 2004. Using electron microscopy, test plant reaction, rapid immuno-filter paper assay (RIPA), reverse transcription-polymerase chain reaction (RT-PCR) and/or analysis of viral nucleotide sequences, we found a number of viruses from 1,056 samples that we collected. These included Cucumber mosaic virus (CMV), Pepper mottle virus (PepMoV), Pepper mild mottle virus (PMMoV), Broad bean wilt virus 2 (BBWV2), Tobacco mild green mosaic virus (TMGMV), and Tomato spotted wilt virus (TSWV). Of the samples analyzed, $343(32.5\%)$ were infected with CMV, $209(19.8\%)$ with PepMoV, $141(13.4\%)$ with PMMoV, $12(1.1\%)$ with BBWV2, $40(3.8\%)$ with TMGMV, $5(0.5\%)$ with TSWV, $153(14.5\%)$ with CMV and PepMoV, $54 (5.1\%)$ with CMV and PMMoV, $31(2.9\%)$ with PepMoV and PMMoV, $3(0.3\%)$ with CMV and BBWV2, $1(0.1\%)$ with CMV, PepMoV and BBWV2, $8(0.8\%)$ with CMV, PepMoV and PMMoV, and $30 (2.8\%)$ samples were infected with viruses which were not identified. CMV was the most predominant virus in all inspected fields and the number of the samples infected with PMMoV was relatively low as compared PepMoV infection level in pepper. TMGMV was only found in the southern part of Korea, while TSWV was isolated in Anyang and Yesan. However, we did not encounter in this survey the Alfalfa mosaic virus (AMV), Potato virus Y (PVY), Tobacco mosaic virus (TMV), and Pepper vein chlorosis virus (PVCV).

• Particle and aerosol research
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• v.19 no.1
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• pp.1-11
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• 2023

Respiratory face masks are protective facepieces that are designed to filter inhaled air. They are easy-to-use devices that can protect the wearer against various hazardous particles in the air. Respiratory face masks also prevent the spread of viruses and bacteria-containing droplets that are released from the coughing or sneezing of the infected people. During the COVID-19 pandemic, various types of face masks have circulated on the market. Their ability to filter sub-micron particles, which are the sizes of harmful particulate matter and airborne viruses, needs to be investigated. Their breathability, the easiness of breath through the mask, also needs to be considered. In this study, wwe evaluated the performance of filters used for different types of face masks certified by different standards including Korean (KF94, KF80, KF-AD), USA (N95), and Chinese (KN95) standards. We also tested the filters of nanofiber masks and surgical masks for which there are no standards for filtration test. The N95 mask filters showed the highest quality factor for capturing virus-sized particles. The other types of mask filters have acceptable performance except for nanofiber mask filters whose performance is very low.