• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.3
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• pp.180-186
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• 2017

Objectives: The purposes of this study were to compare the surface resistance of cassettes according to the material, and to evaluate the wall deposition of carbon nanotubes(CNTs) by electrostatic loss in the inner wall of the cassette. Methods: Surface resistance was measured for three types of cassettes(25 mm polypropylene conductive cowl, 25 mm and 37 mm clear styrene cassettes) with a surface resistance meter. Also, electrostatic wall loss was measured at different weights of CNTs depending on the cassette. CNTs were laid on a weight dish with the cassette for five minutes to provide sufficient time to attach on the wall. Wipe sampling was performed to collect CNTs deposited on the wall and elemental carbon, known as a surrogate for CNTs, was analyzed. Results: The cassette with conductive materials(18% of black carbon) showed the lowest surface resistance($<1.21{\times}10^3{\Omega}$). Cassettes made from clear polystyrene showed the relatively highest surface resistance(25 mm: $10.02{\times}10^9{\Omega}$, 37 mm: $10.59{\times}10^9{\Omega}$). This means that particles are more likely to stick to the internal wall of styrene cassettes due to electrostatic electricity. This may lead to an underestimation of the airborne concentration of CNTs. The experiment showed that EC was not detected when using a 25 mm conductive cowl cassette, while EC was detected at the internal wall of 25 mm and 37 mm polystyrene cassettes. Conclusions: This study confirms that cassettes with a conductive cowl have low surface resistance and are more appropriate for CNT sampling. In addition, this finding could be applied for other types of particulate, especially regarding electrostatic charge and sampling.

• Journal of radiological science and technology
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• v.7 no.1
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• pp.79-84
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• 1984

• Journal of radiological science and technology
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• v.16 no.2
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• pp.61-72
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• 1993

• Journal of Korean Electronics
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• v.7 no.8
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• pp.15-19
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• 1987

• Korean Journal of Microbiology
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• v.41 no.2
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• pp.146-151
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• 2005

To construct an amylolytic industrial strain of Saccharomyces cerevisiae, the glucoamylase cDNA gene (GAl) from Aspergillus awamori was expressed under the control of the alcohol dehydrogenase gene promoter (ADC1p) and integrated into the chromosomes of industrial S. cerevisiae. An integrative cassette lacking bacterial ampicillin resistance gene but containing the GA1 gene, $\delta$ sequences of Ty1 retrotransposon as target sites for homologous recombination and S. cerevisiae aureobasidin A resistance gene (AUR1-C) as the selection marker was constructed to obtain a strain eligible for commercial use. Industrial S. cerevisiae transformed with this 15-integrative cassette efficiently secreted glucoamylase into the medium and grew on starch as the sole carbon source. The transformants were mitotically stable for 100 generations in nonselective medium.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.4
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• pp.348-355
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• 2013

Objectives: In working environment measurement, sampling is an important stage for obtaining reliable result as analysis. A personal air sampling pump is one of the most fundamental and important element in the work environment measurement, but it remains at the level of calibrating the flow rate of the pump before and after sampling. There is no checking whether the flow rate set at the initial stage would be hold during sampling. The purpose of this study was to develop a method to evaluate the flow rate performance of particulate sampling pump with three-pieces cassette holder containing filters commonly used to sample particulate. Materials and methods: We tested back pressure of particulate sampling pumps commonly used in Korea with three-pieces cassette holder containing various filters, and tried to find out the combination conditions of filters in accordance with back pressure required by ISO standard 13137. Results: We found out the matrix of sampling media such as three-pieces cassette holder containing filters applicable to the pressure drop required by the ISO standard for evaluating the flow rate stability under increasing pressure drop and long term(8 hour) performance. Conclusions: This evaluation method using sampling media matrix for checking flow rate stability proposed by this study could be very useful tool to find out good performance pumps before sampling.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.501-508
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• 2015

There are various Intercondyloid fossa X-ray taking methods. The methods carried out in clinics are Holmblad method, Camp-Conventry method, and Beclere method. Taking image of Intercondyloid fossa is carried a lot as basic examination for diagnosis related to simple fracture and cruciate ligament. Considering the condition and pains of patients, safe method is chosen but because Holmblad method can cause pains to knee part adhering to cassette, it is not easily used. In this study self-produced plane circular cone was attached to a cassette and in the posture for Holmblad method questionnaires of 100 applicants were analyzed to understand cognition on alleviation of pains, and the concentration of imge quality by scattering rays was measured with densitometer by taking human body phantom with X-ray. As a result, in the posture for Holmblad method, cognition on pains was alleviated by average 99%, and the change of concentration of X-ray film taken using phantom by scattering rays decreased statistically significantly compared to the cassette which did not use self-produced plane cone, therefor it is thought that the method can be valuably used in clinics.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.233-240
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• 2010

Methicillin-resistant coagulase-negative staphylococci (MRCNS) were isolated from the respiratory sites of chickens in 4 farms and slaughter house located in Chungnam provinces. Isolation of coagulase-negative staphylococci (CNS) was positive for 61 (26.6%) of the 229 chickens tested, and isolation of MRCNS was positive for 17 (27.9%) of the isolated CNS. A total of 17 MRCNS isolates were selected and subjected to identification. Of the 17 MRCNS isolates selected, 6 were identified as Staphylococcus cohnii, 2 as S. saprophyticus, 3 as S. simulans, 3 as S. lentus, 2 as S. carnosus, and 1 as S. xylosus. The MRCNS isolates were resistant to many beta-lactam antibiotics, and some isolates were also resistant to macrolide and aminoglycoside antibiotics. The mecA gene was detected in some isolates of each MRCNS strains. The mecA-positive isolates were classified into five staphylococcal cassette chromosome mec (SCCmec). SCCmec types I to IV were detected in isolates from chickens.

• Journal of radiological science and technology
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• v.31 no.3
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• pp.229-237
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• 2008

Purpose : For the number of microbes and the pollution level of bacteriology of IP Cassette and Table by laboratories, after identifying the bacteria before and after using alcohol and tissue including disinfectant and statistically testing, this research was intended to provide the basic data for the prevention and the right disinfection guideline for infection management of hospitals in diagnostic radiology. Subject and Method : The subject of this research was the general room of diagnostic radiology of a university hospital in Daejeon City. The research was conducted from Apr 5 to Apr 12, 2007. The number of microbes and the pollution level of bacteriology of IP Cassette and Table by laboratories were tested before and after using alcohol and tissue for disinfection including disinfectant. In order to collect specimens exactly, they were collected with the nurse who specialized in infection management of the hospital, and statistical processing was done with SPSS V13.0. To compare the results before and after using alcohol and tissue, T-test was implemented, and post-hoc test was conducted. Results : Bacteria were detected in 19 cases of 24 subjects(79.2%), however, they were not detected in 5 cases(20.8%). 7kinds of bacteria were detected as isolated bacteria, of which Methicillin Resistant coagulase-negative Staphylococci(MRCNS) were detected in 15 cases(62.5%), which was most, Methicillin Resistant Staphylococcus Aureus(MRSA) in 6 cases(16.7%), Enterococcus Faecium(EFM) in 5 cases(20.8%), Acinetobacter baumannii(ABA) in 2 cases(8.3%), and Bacillus sp, Coagulase-negative Staphylococci(CNS), and Enterococcus sp(ENT) in 1 case, respectively(4.2%). In all bacteria except ABA, Gram positive bacillia were detected in 30 cases(97%), and Gram negative bacilli were detected only in 1 case(3%). As for the kinds of bacteria and the number of groups before and after using 70% Alcohol by Groups, when the bacteria were identified after disinfecting IP Cassette and Table with 70% Alcohol, all the bacteria became extinct in both IP Cassette and Table Group(100%). As for the kinds and number of bacteria before and after using Tissue Cleaner by Groups, the bacteria in Tissue Cleaner Group became completely extinct only in 10 Groups(71.2%), and in 4 Groups, there was much decrease in bacteria, however, they were still detected. The extinction rate of all the bacteria was 91.5%. That is, though the other bacteria became extinct(100%), that of MRCNS bacteria was lowest(83.6%), followed by MRSA(95%). Conclusion : As a result of comparing the mean of the bacteria which were detected before and after using 70% Alcohol and Tissue Cleaner, there was statistically significant in the significant level of 5% in both of them.

• BMB Reports
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• v.40 no.5
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• pp.656-661
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• 2007

In this report, we describe an optimized method for generation of ephA8 BAC transgenic mice expressing the lacZ reporter gene under ephA8 regulatory sequences. First, we constructed a targeting vector that carries a 1.2 kb ephA8 DNA upstream of its first exon, a lacZ expression cassette, a kanamycin cassette, and a 0.7 kb ephA8 DNA downstream of its first exon. Second, the targeting vector was electroporated into cells containing the ephA8 BAC and pKOBEGA, in which recombinases induce a homologous recombination between the ephA8 BAC DNA and the targeting vector. Third, the FLP plasmid expressing the Flipase was electroporated into these bacteria to eliminate a kanamycin cassette from the recombinant BAC DNA. The appropriate structures of the modified ephA8 BAC DNA were confirmed by Southern analysis. Finally, BAC transgenic mouse embryos were generated by pronuclear injection of the recombinant BAC DNA. Whole mount X-gal staining revealed that the lacZ reporter expression is restricted to the anterior region of the developing midbrain in each transgenic embryo. These results indicate that the ephA8 BAC DNA contains most, if not all, regulatory sequences to direct temporal and spatial expression of the lacZ gene in vivo.