• 제목/요약/키워드: ARS

검색결과 534건 처리시간 0.025초

Isolation and ars Detoxification of Arsenite-Oxidizing Bacteria from Abandoned Arsenic-Contaminated Mines

  • Chang, Jin-Soo;Yoon, In-Ho;Kim, Kyoung-Woong
    • Journal of Microbiology and Biotechnology
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    • 제17권5호
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    • pp.812-821
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    • 2007
  • The ecosystems of certain abandoned mines contain arsenic-resistant bacteria capable of performing detoxification when an ars gene is present in the bacterial genome. The ars gene has already been isolated from Pseudomonas putida and identified as a member of the membrane transport regulatory deoxyribonucleic acid family. The arsenite-oxidizing bacterial strains isolated in the present study were found to grow in the presence of 66.7 mM sodium arsenate($V;\;Na_2HAsO_4{\cdot}7H_2O$), yet experienced inhibited growth when the sodium arsenite($III;\;NaAsO_2$) concentration was higher than 26 mM. Batch experiment results showed that Pseudomonas putida strain OS-5 completely oxidized 1 mM of As(III) to As(V) within 35 h. An arsB gene encoding a membrane transport regulatory protein was observed in arsenite-oxidizing Pseudomonas putida strain OS-5, whereas arsB, arsH, and arrA were detected in strain OS-19, arsD and arsB were isolated from strain RW-18, and arsR, arsD, and arsB were found in E. coli strain OS-80. The leader gene of arsR, -arsD, was observed in a weak acid position. Thus, for bacteria exposed to weak acidity, the ars system may cause changes to the ecosystems of As-contaminated mines. Accordingly, the present results suggest that arsR, arsD, arsAB, arsA, arsB, arsC, arsH, arrA, arrB, aoxA, aoxB, aoxC, aoxD, aroA, and aroB may be useful for arsenite-oxidizing bacteria in abandoned arsenic-contaminated mines.

Characterization of the Plasmid-Encoded Arsenic Salts Resistance Determinant from Klebsiella oxytoca D12

  • Rhie, Ho-Gun;Lee, Sung-Jae;Lee, Ho-Sa
    • Journal of Microbiology and Biotechnology
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    • 제14권3호
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    • pp.593-598
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    • 2004
  • The arsenical resistance (ars) operon was cloned from a 67-kilobase pair (kb) plasmid, which was previously shown to be responsible for arsenic salts resistance in K. oxytoca D12. When plasmid pAE48, carrying the ars operon, was transformed into E. coli, transformed cells displayed enhanced survival in the presence of 4 mM arsenite, 50 mM arsenate, or 0.4 mM antimonite. The nucleotide sequence of the 5.6-kb fragment encoding arsenical resistance revealed five open reading frames (ORFs), which were predicted to encode polypeptides of 12.8 (arsR), 13.4 (arsD), 62.6 (arsA), 45 (arsB), and 16.7 (arse) kilodaltons (kDa). Each ORF was preceded by a ribosome binding site. A putative promoter-like sequence was identified upstream of arsR, and a possible termination site was found downstream of arsC. When the deduced amino acid sequences of the K. oxytoca Dl2 Ars proteins were compared with the amino acid sequences of the E. coli R773 Ars proteins, a significant amino acid similarity was observed (87.9% for ArsR, 89.2% for ArsD, 83.2% for ArsA, 92.6% for ArsB, and 91.3% for ArsC), suggesting an evolutionary relationship of the ars genes of E. coli plasmid R773 and K. oxytoca Dl2.

ARS 사용성 테스트를 위한 시뮬레이터 구현 (Implementation of an ARS Usability Testing Simulator)

  • ;김희철
    • 한국정보통신학회논문지
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    • 제15권12호
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    • pp.2679-2686
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    • 2011
  • 음성자동응답시스템(ARS)은 광범위하게 사용되는 대표적인 커뮤니케이션 시스템임에도 불구하고, 사용하기가 불편하다는 의견이 지배적인 시스템이다. 이러한 아이러니는 ARS 기술 자체에 대한 문제보다는 사용성에 대한 연구가 요구됨을 보여준다. 아직 국내외적으로 ARS 사용성에 대한 연구와 그 결과들이 빈약한 상황에서, 본 연구에서는 ARS 사용성 연구를 효율적으로 수행하기 위한 ARS 시뮬레이터를 소개한다. ARS 시뮬레이터는 ARS 사용성 연구자들을 위한 시스템으로, ARS 모의 태스크 설계와 사용자의 수행을 돕는 환경을 제공하며, 사용자들의 모의 태스크 과정 저장 및 간단한 사용자 행동 분석을 제공한다.

Neurospora crassa ars-1 프로모터의 발현율 조사 (Transcription level of the ars-1 promoter of Neurospora crassa)

  • 이병욱;구상호
    • 생명과학회지
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    • 제13권2호
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    • pp.191-196
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    • 2003
  • Arylsulfatase를 암호화하는 Neurospora crassa의 ars-1 유전자는 황의 결핍에 의해서 발현이 조절된다. lacZ 유전자에 연결된 ars-1 프로모터 (Pars)가 N. crassa RLM 35-35 a his-3 inl 균주에 형질전환되고, 유사 서열 재조합에 의한 단일 교차에 의해서 염색체의 his-3 부위로 도입이 되었다. 황이 결여된 Vogel의 배지에서 자란 균사로부터 $\beta$-galactosidase 활성이 측정되었다. $\beta$-galactosidase 활성은 derepression 조건으로 변환한지 14 시간 후에 최고치를 기록하였다. Microconidiation에 의해서 생산된 homokaryon에서 측정된 활성은 heterokaryon보다 17% 증가가 되었음을 보여주었다. 이 실험은 ars-1 프로모터의 발현율을 측정할 수 있는 한 방법을 제시한 것으로, 보다 수월한 ars-1 발현 조절 연구가 기능할 것이다.

Sliding Mode Control 및 Fuzzy Logic Control 방법을 이용한 AFS 및 ARS 제어기 설계 및 성능 평가 (Design and Evaluation of AFS and ARS Controllers with Sliding Mode Control and Fuzzy Logic Control Method)

  • 송정훈
    • 한국자동차공학회논문집
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    • 제21권2호
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    • pp.72-80
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    • 2013
  • This study is to develop and evaluate an AFS and an ARS controllers to enhance lateral stability of a vehicle. A sliding mode control (SMC) and a fuzzy logic control (FLC) methods are applied to calculate the desired additional steering angle of AFS equipped vehicle or desired rear steer angle of ARS equipped vehicle. To validate AFS and ARS systems, an eight degree of freedom, nonlinear vehicle model and an ABS controllers are also used. Several road conditions are used to test the performances. The results showed that the yaw rate of the AFS and the ARS vehicle followed the reference yaw rate very well within the adhesion limit. However, the AFS improves the lateral stability near the limit compared with the ARS. Because the SMC and the FLC show similar vehicle responses, performance discrimination is small. On split-${\mu}$ road, the AFS and the ARS vehicle had enhanced the lateral stability.

Comparison of Tibial Tuberosity Transposition and Anti-rotation Suture for Medial Patellar Luxation in 133 Small-breed Dogs

  • Son, Chansoo;Cheong, Jongtae;Lee, Joo Myoung
    • 한국임상수의학회지
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    • 제35권5호
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    • pp.200-205
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    • 2018
  • This retrospective study is designed to compare the clinical results of tibial tuberosity transposition (TTT) and anti-rotation suture (ARS) treatments for medial patellar luxation (MPL). Medical records of 133 dogs were reviewed that had undergone surgical correction of MPL between January 2013 and May 2017. MPL correction was performed on 182 stifles, with TTT and ARS being performed on 101 stifles and 81 stifles. The common dog breeds receiving surgical treatment for MPL were Maltese, Pomeranian, Chihuahua and Poodle. Mean age of dogs with MPL was 32.6 months, and their mean body weight was 4.26 kg. Seventy dogs (52.6%) were male and 63 (47.4%) were female. Of the 182 stifles with MPL, grade II, III and IV were 18.7%, 72.0% and 9.3%. Total complications after TTT and ARS were recorded in 16.8% and 29.6%. Major complications after TTT and ARS were recorded in 5.9% and 12.3%, minor complications after TTT and ARS were recorded in 10.9% and 17.3%. The risk of complication and reluxation rate after TTT were significantly lower than that for ARS (p < 0.05). However, the rate of reluxation among dogs treated by ARS (1.2%) for grade II MPL was significantly lower than that for dogs treated by ARS (8.6%) for grade III MPL (p < 0.05). The TTT group had a shorter recovery period after surgical intervention than that in the ARS group (p < 0.001). In conclusion, TTT had a significantly lower incidence of complication and a shorter recovery period than ARS. However, ARS for grade II MPL appears to be a good surgical option for reducing the rate of reluxation after surgery. These results of this study could be used to provide therapeutic guidelines for surgical MPL correction in small-breed dogs.

ARS 메뉴체계 사용성 저해요소에 대한 실험연구 (An Experimental Study on Hindrance Factors of Usability of Menu Structure in ARS)

  • 김호원;김희철
    • 한국정보통신학회논문지
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    • 제15권2호
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    • pp.462-470
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    • 2011
  • 음성자동응답시스템(Automatic Response Systems, ARS)은 VUI(Voice User Interface)와 TTI(Touch Tone Interface)를 기반으로 하고 있으며, 현재 가장 널리 사용되는 커뮤니케이션 시스템 중 하나이다. 그러나 많은 사용에도 불구하고, ARS에 대한 불편 사항들이 끊임없이 지적되고 있다. 이는 기술 개발을 넘어, 사용자와 사용성에 대한 체계적인 연구 부족에서 기인한 측면이 있다. 본 논문에서는 ARS 메뉴체계에서의 사용성 저해 요소를 발견 분석하여, ARS 설계를 위한 개선의 지침을 제공한다. 두 개의 인터넷 서점 ARS를 선정하여 피실험자들이 "도서 반품 신청하기"라는 작업을 실행한 후 정해진 설문조사 결과와 인터뷰 내용을 분석하였다. 본 연구에서 메뉴 구조의 복잡성, 메뉴명의 대표성 부족, 사용자 위치인지의 어려움, 메뉴간 이동의 어려움 등 네 가지 문제들을 발견하였고, 이를 피할 수 있는 방법들을 논의하였다.

동아시아의 인공어초 개발과 연구 현황 (A Review-Status of Development and Research of Artificial Reefs in the East Asian Countries-)

  • 이문옥;김종규;김병국
    • 수산해양교육연구
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    • 제28권3호
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    • pp.630-644
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    • 2016
  • We conducted a comprehensive review on artificial reefs (ARs) including seaweed reefs for marine afforestation in relation to their development and research from 1972 to 2016, and then systematically analyzed their current a state-of-the-art and practice. From the review, the followings conclusions are made. First, the objectives of AR projects in the Southeast Asia can be classified into three, i.e. protection and increase of fishery resources, local community's profits, and ecological tourism. Second, fish gathering effects by ARs can be determined in terms of wake region or wake length that tends to increase with the K-C (Keulegan-Carpenter) number. Third, ARs are desirable to deploy across a direction of the main flow but it is essential to keep the deployment interval two to four times the length of a single reef. Fourth, stability of ARs depends on how to evaluate drag coefficient, and Morison formula turns out to be practical. Fifth, local scours of ARs are likely to occur due to a downward flow around the center of the front surface. Finally, it is natural for ARs to positively contribute to the marine ecosystem but it is imperative to develop an evaluation method for the effects of ARs on the marine ecosystem.