• 대한수학회보
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• 제60권2호
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• pp.315-323
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• 2023

First, we recall the results for prime-producing polynomials related to class number one problem of quadratic fields. Next, we give the relation between prime-producing cubic polynomials and class number one problem of the simplest cubic fields and then present the conjecture for the relations. Finally, we numerically compare the ratios producing prime values for several polynomials in some interval.

• 대한수의학회지
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• 제36권3호
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• pp.607-614
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• 1996

Several methods for rapid and accurate detection of VTe-producing E coli were established. These methods contain beta-glucuronidase-secretion test, beta-haemolysis-production test in blood agar, verocytotoxicity test, and PCR. All of the VTe-producing strains made beta-haemolysis on 5% sheep blood agar. VTe-producing strains secreted beta-glucuronidase whereas 0157:H7 strains producing VTI or VTII did not secrete that enzyme. Verocytotoxicity test was established for rapid diagnosis. VTe detection was rapider in Vero cell suspension than Vero cell monolayer. In PCR, there was a positive result only in VTe-producing E coli, not in VTI or VTII-producing E coli. In this experiment, 165 strains of E coli were islated from feces or intestinal contents of post-weaning piglets showing nervous sign or diarrhea. And 20 strains of E coli that produced VTe were selected by verocytotoxicity test and PCR. According to these experiments, there was a direct correlation between verocytotoxicity test and PCR. And verocytotoxicity test is recommended as a routine diagnostic method and PCR does as a accurate diagnostic method to detect VTe-producing E coli.

• Biomolecules & Therapeutics
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• 제7권1호
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• pp.44-53
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• 1999

The resistant strains due to the extended-spectrum $\beta$-lactamase (ESBL) were susceptible to cefatrizine combined with clavulanic acid. The purpose of this study was to evaluate the in vitro and in vivo antibacterial activities of cefatrizine/clavulanic acid (CTRZ/CV) combination at a ratio of 2 : 1 in comparison with cefaclor (CCLO), cefuroxime (CRXM), cefuroxime axetil (CRXMA) and amoxicillin/clavulanic acid (AMXCCV). CTRZ/CV showed good activity against laboratory strains of gram-positive and gram-negative bacteria and exhibited excellent antibacterial activity against $\beta$-lactamase-producing strains. The bactericidal activity of CTRZ/CV was superior to that of CCLO and CRXM, and almost equal to that of AMXCCV against the $\beta$-lactamase-producing strains. The in vitro results were substantiated. by in vivo mouse experimental infection studies with $\beta$-lactamase-producing and non-producing strains. In mixed experimental infection due to $\beta$-lactamase-producing and non-producing strains, the therapeutic efficacy of CTRZ/CV was superior to that of CTRZ, CCLO, CRXMA and AMXCCV. In respiratory tract infection in mice due to Klebsiella pneumoniae EB4O, CTRZ/CV was more erective than CCLO, CRXMA and AMXCCV and also more efficacious than CCLO, CRXMA and AMXCCV in urinary tract infection in mice due to Escherichia coli EB13. These results indicate that CTRZ/CV is a useful drug for the treatment of infection caused by $\beta$-1actamase-producing strains including ESBL-producing strains.

• 환경위생공학
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• 제13권2호
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• pp.34-39
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• 1998

For more convenient and rapidly isolation of Bacillus thuringiensis subsp. israelensis(Bti), 1) heat treatment spore forming bacteria, 2) growth in enrichment culture media for Bacillus sp. and 3) selection of bacteria producing a lecithinase for Bacillus thuringiensis subsp. israelensis, were performed. Spore forming bacteria were counted 4.8 $\times $ 10$^{8}$cells/g soil on NAPGCY media, 9.2 $\times $ 10$^{7}$cells/g soil on NA media, and 3.6 $\times $ 10$^{8}$cells/g soil on NAAC media, respectively. Bacteria producing only a lecithinase were reached at 25.2% on medium contained egg york, bacteria only producing a delta-endotoxin were reached at 23.2% by phase contrast microscope, and bacteria producing a lecithinase & a delta-endotoxin simultaneously were reached at 13.7%. Bacillus thuringiensis which producing a lecithinase and a delta-endotoxin simultaneously among bacteria producing a lecithinase, were reached at 56.5%; A half of Bacillus thuringiensis was produced a delta-endotoxin, but not produced a lecithinase. Among 8 isolates of Bacillus thuringiensis, two strain of Bti which has a mosquito-cidal toxin, were detected by PCR using a specific primer of $\delta $-endotoxin gene from Bti.

• 한국가축번식학회지
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• 제19권1호
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• pp.35-41
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• 1995

본 연구는 형질전화우의 생산성 제고를 위한 일환으로서 새로운 기법인 retrovirus vector system의 이용성을 검토하고자 실시하였다. Retrovirus-producing cell은 미세주입법을 이용하여 체외생산된 1.5일(1~4-세포기) 수정란의 위란강에 주입(5~10 cells/embryo) 되었으며, 이때 사용된 retrovirus-producing cell line은 Gibbon ape leukemia virus (GaLV) envelope protein에 encapsidation되어 replication-defective retrovirus를 분비하도록 제작되었다. 주입된 유전자의 표지유전자로서 E. coli LacZ 유전자를 사용하였으며, X-gal 염색법은 발달이 유도된 상실배와 배반포 단계에 실시하여 LacZ 유전자의 발현 유무를 확인하였다. 이 실험의 결과를 요약하면 다음과 같다. 1. Virus의 infectivity를 높이기 위해 사용된 polybrene의 최저농도는 5$\mu\textrm{g}$/ml이었다. 2. Retrovirus-producing cell이 주입된 1.5일 수정란의 상실배기와 배반포기로의 발달율은 29%였다. 3. 이 때의 LacZ+ 발현율은 21%였다. 4. 본 실험에 사용된 retrovirus-producing cell은 replication-competent retroviruses를 생산해 내지않는다는 것을 확인할 수 있었다.

• 한국콘텐츠학회논문지
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• 제7권8호
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• pp.117-124
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• 2007

1인 제작시스템은 방송 프로그램 제작에 있어 혼자서 프로그램을 기획하고 섭외, 구성, 촬영, 편집까지 1인이 담당하는 제작 시스템을 말한다. 방송프로그램 제작 현실에 있어 6mm 디지털카메라를 이용한 1인 제작시스템을 운영하는 방송사가 점차적으로 늘어나고 있어 이러한 변화에 대한 연구가 진행되고 있다. 본 연구는 다인(多人) 제작시스템과 1인 제작시스템의 장 단점을 파악해보고 방송계에서 프로그램 제작방식으로 급부상하고 있는 6mm 디지털카메라를 이용한 프로그램 제작의 변화를 분석해 보았다. 6mm 제작 프로그램의 장점으로는 제작의 기동성과 취재원과의 밀착성, 다양한 소재의 확대, 제작비 절감 등을 꼽을 수 있으나, 프로그램의 완성도 저하 및 영상의 불안정성 등을 단점으로 지적할 수 있다. 현재에 이르러 방송프로그램의 외주제작 비율의 확대로 인해 독립제작사의 수가 급증하였으며, 제작비 절감과 프로그램의 다양성 측면에서 1인 제작시스템을 이용한 프로그램 편성이 늘어나는 결과를 가져왔다.

• 말소리와 음성과학
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• 제2권3호
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• pp.23-27
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• 2010

The purpose of this study was to find how English vowels /a, e, i, o, u/ affect the production of English labials /p, b, f, v/ by Korean learners of English. Sixty syllables were composed by five vowels and four labials in the syllable types CV, VC, and VCV. The nonsense syllables were produced three times by nine subjects. The major results show that (1) in inter-vocalic position, the subjects had higher scores in producing /v/ composed with /a, e, o/ and /u/, while subjects had lower scores in producing /p/ with /i/ and /o/, (2) in post-vocalic position, the subjects had higher scores in producing /v/ and /f/ with /a, e/, and /o/, while subjects had lower scores in producing /b/ with /e/ and /i/, and (3) in pre-vocalic position, the subjects had higher scores in producing /v/ with /e, o, u/ and /f/ with /u/, while subjects had lower scores in producing /b/ with /e/, /i/ and /u/. The results suggest that on the whole, Korean learners of English have much difficulty in producing /p/ with /i/ in inter-vocalic condition and /b/ with /i, /e/ in pre-vocalic position.

• 한국수산과학회지
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• 제49권6호
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• pp.792-799
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• 2016

We isolated seven tryptamine-producing bacteria from commercial salted and fermented sand lance (Ammodytes personatus) sauces using an L-tryptophan decarboxylating medium. These tryptamine-producing bacteria, identified using an API kit and 16S rRNA analysis, included Lysinibacillus xylanilyticus (one strain), Lysinibacillus fusiformis (four strains), and Staphylococcus epidermidis (two strains). Lysinibacillus spp. produced the highest levels of tryptamine in culture broth containing 0.5% L-tryptophan, compared with 1.0% and 2.0% preparations. After 72 h of incubation, Staphylococcus epidermidis produced the highest levels of tryptamine ($60.50{\mu}g/mL$ and $664.86{\mu}g/mL$) in culture broth containing 2.0% L-tryptophan. While Lysinibacillus spp. comprised the dominant tryptamine-producing bacteria in sand lance sauces, Staphylococcus epidermidis also showed high tryptamine-producing activity. This is the first report on the isolation and identification of tryptamine-producing bacteria in sand lance sauces.

• 한국산림과학회지
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• 제72권1호
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• pp.27-31
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• 1986

송이발생림(松栮發生林)과 미발생림(未發生林)의 고등균류(高等菌類)의 분포(分布)와 균근(菌根)버섯의 역할(役割)을 비교분석(比較分析)하기 위하여, 강원도(江原道) 양양군(襄陽郡) 현북면(縣北面)에 위치(位置)한 두 적송림(赤松林)에서 송이(松栮)가 발생(發生)하는 기간(期間)인 1984년(年) 9월(月) 25일(日)에 지상(地上)에서 발생(發生)하는 버섯을 채집(採集)하여 분류(分類)하였다. 평균(平均) 28년생(年生)인 송이발생림(松栮發生林)에서는 총(總) 12속(屬) 18종(種)을 채집(採集)하였으며, 그 중(中) 1종(種)을 제외(除外)한 나머지 17종(種)은 모두 균근(菌根)버섯이었다. 흔한 버섯 속(屬) Suillus, Russula, Lactarius, Hydnum, Amanita속(屬)이었다. 평균(平均) 55년생(年生)인 송이발생림(松栮發生林)에서는 총(總) 22속(屬) 30종(種)의 버섯을 채집(採集)하였는데, 그 중(中) 22종(種)이 균근(菌根)버섯이었고, 8종(種)은 부후균(腐朽菌)이었다. 흔한 버섯속(屬)은 Hydnum, Tyicholoma, Laccaria, Cantharellus속(屬)이었다. 두 임분(林分)에서 함께 발현(發見)된 버섯은 6종(種)이었다. 송이발생림(松栮發生林)은 성숙(成熟)한 임분(林分)으로써 미발생림(未發生林)에 비(比)해서 유기질(有機質)의 함량(含量)이 많고 하층식생(下層植生)이 더 발달(發達)해 있었으며, 이에 따라서 더 다양(多樣)한 버섯의 분포(分布)를 나타냈으며, 상대적(相對的)으로 송이(松栮)를 포함(包含)한 균근(菌根)버섯의 비율(比率)이 낮아졌다고 할 수 있다.

• 대한수의학회지
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• 제55권3호
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• pp.191-197
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• 2015

Escherichia (E.) coli is commensal bacteria found in the intestine; however, some pathogenic strains cause diseases in animals and humans. Although E. coli does not typically produce hydrogen sulfide ($H_2S$), $H_2S$-producing strains of E. coli have been identified worldwide. The relationship between virulence and $H_2S$ production has not yet been determined. Therefore, characteristics of $H_2S$-producing isolates obtained from swine feces were evaluated including antibiotic resistance patterns, virulence gene expression, and genetic relatedness. Rates of antibiotic resistance of the $H_2S$-producing E. coli varied according to antibiotic. Only the EAST1 gene was detected as a virulence gene in five $H_2S$-producing E. coli strains. Genes conferring $H_2S$ production were not transmissible although the sseA gene encoding 3-mercaptopyruvate sulfurtransferase was detected in all $H_2S$-producing E. coli strains. Sequences of the sseA gene motif CGSVTA around Cys238 were also identical in all $H_2S$- producing E. coli strains. Diverse genetic relatedness among the isolates was observed by pulsed-field gel electrophoresis analysis. These results suggested that $H_2S$-producing E. coli strains were not derived from a specific clone and $H_2S$ production in E. coli is not associated with virulence genes.