• Journal of electromagnetic engineering and science
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• 제7권1호
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• pp.47-52
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• 2007

We investigated the effects of substrate, metal-line, and surface material on the performance of radio frequency identification(RFID) tag antenna using a tag antenna with a meander line radiator and T-matching network. The results showed that readability of the tag antenna with a thin high-loss substrate could be increased so that it was similar to that of a low-loss substrate if the substrate was very thin. The readability of the tag antenna decreased significantly when the metal line was thinner than the skin depth. The readability of the tag also decreased drastically when the tag was attached to high-permittivity high-loss target objects.

• BMB Reports
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• 제33권3호
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• pp.242-248
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• 2000

Phage display of proteins is a powerful tool for protein engineering since a vast library of sequences can be rapidly screened for a specific property. In this study, we develop da new phage display vector that was derived from a pET-25b(+) vector. The pET-25b(+) was modified in order that the expressed protein would have a T7-tag at the amino terminus and GpS (a major coat protein of M13 phage) at the carboxyl terminus. Another vector without the gp8 gene was also constructed. The newly developed phagemid vectors have several advantageous features. First, it is easy to examine whether or not the target proteins are functional and faithfully transported into the periplasmic space. This feature is due to the fact that recombinant proteins are produced abundantly in the pET system. Second, the T7-tag makes it possible to detect any target proteins that are displayed on the surface of filamentous bacteriophage. To verify the utility of the vector, the clones containing the glutathione S-transferase (GST) gene as a target were examined. The result showed that the GST produced from the recombinant vector was successfully transported into the periplasmic space and had the anticipated enzyme activity. Western blot analysis using a T7-tag antibody also showed the presence of the target protein displayed on the surface of the phage. The phages prepared from the recombinant clones were able to bind to glutathione-Sepharose and then eluted with glutathione. These results showed that the new vectors developed in this study are useful for the phage display of proteins.

• 한국전자파학회논문지
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• 제16권12호
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• pp.1206-1212
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• 2005

본 논문에서는 전기 전류와 자기 전류를 동시에 생성하여 인식 음영 구역을 제거할 수 있는 새로운 형태의 RFID 태그 안테나를 설계하였다. 변형된 이중 T 매칭 네트워크를 이용하여 상용 태그 칩을 안테나에 공액 정합을 시켜, 848${\~}$926 MHz의 넓은 대역폭($S_{11}< -10 dB$)과 $90\%$ 이상의 높은 복사 효율을 얻었다. 제안한 안테나는 동작 주파수 부근에서 최대 이득과 최소 이득의 차이가 약 4 dB로 유사 등방성 복사 패턴을 가지며, 상용 태그칩을 장착하여 인식 거리를 측정한 결과 태그의 방향과 무관하게 1.7${\~}$2.4 m의 고른 인식 능력을 보였다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제36권7호
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• pp.560-570
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• 2009

RFID 기술은 바코드를 대체할 자동인식 기술로서 인식 속도가 빠르고 비접촉 방식으로 오염에 강한 장점을 가지고 있다. 그러나 RFID 기술의 대중화를 위해서는 선결되어야할 난제들이 있다. 이 중 본 논문에서는 다중 태그 식별 문제를 다룬다. 다중 태그를 인식하고 충돌을 방지하는 문제는 RFID 시스템의 성능에 직접적인 영향을 준다. 본 논문에서는 기존의 알고리즘들을 분석하고 개선하된 새로운 태그 충돌 방지 알고리즘을 제안한다. 제안된 알고리즘은 ALOHA 기반 알고리즘과 QT 기반 알고리즘의 하이브리드 형태로 분배와 인식 과정에 적합한 특성들을 혼합하여 구성하였다. 분배 과정에서는 ALOHA 방식을 이용하여 인식과정에서 한 프레임에 인식해야할 태그 수를 줄였다. 이는 Tree 의 깊이가 깊어져 지연을 일으키는 문제를 해결하였다. 인식 과정에서는 QT 기반 알고리즘을 이용하여, ALOHA 방식에서 모든 태그를 인식하지 못하는 문제를 해결하였다. 또한, 실제 RFID 환경을 분석하여 더 좋은 성능을 보이도록 태그ID 의 역순으로 인식하는 QTR 알고리즘을 적용하였다. 본 논문에서 제안하는 FQTR 알고리즘은 시뮬레이션 결과 기존의 알고리즘에 비해 뛰어난 성능을 보여주었다.

• Journal of Communications and Networks
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• 제14권1호
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• pp.34-39
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• 2012

Collisions between tags greatly reduce the identification speed in radio frequency identification (RFID) systems and increase communication overhead. In particular for an active RFID system, tags are powered by small batteries, and a large number of re-transmissions caused by collisions can deteriorate and exhaust the tag energy which may result in missing tags. An efficient collision-free arbitration protocol for active RFID systems is proposed in this paper. In this protocol, a new mechanism involving collision detection, collision avoidance, and fast tag access is introduced. Specifically, the pulse burst duration and busy-tone-detection delay are introduced between the preamble and data portion of a tag-to-reader (T-R) frame. The reader identifies tag collision by detecting pulses and transmits a busy tone to avoid unnecessary transmission when collision occurs. A polling process is then designed to quickly access the collided tags. It is shown that the use of the proposed protocol results in a system throughput of 0.612, which is an obvious improvement when compared to the framed-slotted ALOHA (FSA) arbitration protocol for ISO/IEC 18000-7 standard. Furthermore, the proposed protocol greatly reduces communication overhead, which leads to energy conservation.

• 대한의생명과학회지
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• 제8권3호
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• pp.107-113
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• 2002

Enterohemorrhagic Escherichia coli (EHEC) strains of serotype O157:H7 have been shown to colonize the intestinal epithelial cell by the attaching and effacing (AE) mechanism. The AE lesion is mediated by an intimin, of which production and expression are controlled by a 3-Kb eaeA gene located EHEC chromosomal DNA. If the eaeA gene is mutated, EHEC O157:H7 strains lose capacity of adhesion to intestinal epithelial cells. In this study, a 891 bp of the 3'-end region of a gamma intimin was amplified by polymerase chain reaction (PCR). The PCR product was inserted into pSTBlue-1 cloning vector and transformed into DE3 (BL21) competent cell. After plasmid mini-preparation and restriction enzyme digestion of eaeA/891-pSTBlue-1 vector, target eaeA gene was re-inserted into pET-28a expression vector and was transformed. Then the expression of recombinant eaeA/891 (891 bp) gene was induced by isopropyl-$\beta$-D-thiogalactopyranoside (IPTG). The expression of the 40-KDa recombinant protein was identified in SDS-PAGE and confirmed by immunoblotting using the His.Tag$^{\circledR}$ and T$_{7}$.Tag$^{\circledR}$ monoclonal antibody. This recombinant protein expressed by eaeA gene could be applied in further studies on the mechanisms of E. coli O157:H7 infection and the development of recombinant vaccine.

• Journal of Microbiology
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• 제38권2호
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• pp.109-112
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• 2000

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic hematopoietic growth factor and an activator of lmature myeloid cells and recombinant GM-CSF is increasingly under clinical studies for the treatment of various diseases including cancer, infectious diseases and hematopoietic diseases. We constructed a reconbinant mouse GM-CSF expression plasmid with pelB leader sequence and His. Tag under T7 promoter control, and showed that the construct produced a 20 kDa recombinant protein in 8M urea. We also showed that the 20 kDa recombinant protein prepared in 8M urea sitmulated colony formation in vitro, indicating that the recombinant mGM-CSF can be renatured to its native form to show the colony stimulating activity.

• 미생물학회지
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• 제33권1호
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• pp.1-6
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• 1997

5-Enolpyruvylshikimate 3-phosphate(EPSP) synthase는 방향족 아미노산을 생합성하는 shikimate phathway의 6번째 효소로 광범위 제초제인 glyphosate의 target enzyme이다. 본 연구에서는, glyphosate에 저해를 받지 않는 EPSP synthase를 개발하고자 하는 연구의 한 단계로서, 우선, EPSP synthase를 대량 발현시킬수 있는 expression vector인 pET-25b를 사용하여 발현시킨 다음, 발현된 효소가 periplasmic space로 transport되는지 또 발현된 단백질이 효소 활성을 가지고 있는지 확인하고자 하였다. 그 결과, pelB leader를 앞에 붙여 발현시킨 EPSP synthase는 periplasmic space로 제대로 transport되며, 단백질 생산 및 periplasmic space로의 수송은 induction 온도에 의해 크게 좌우된다는 것을 관찰하였다. Periplasmic space로 수송되는 EPSP synthase의 양은 $34^{\circ}C$에서 induction시켰을 때 가장 많은 것으로 나타났다. 한편, pET-25b를 이용하여 발현시킨 EPSP synthase는 C-terminal 부위에 HSV-tag, His-tag등 26개 아미노산이 더 있는 상태로 만들어지는데, His-tag은 $Ni^{2+}$-affinity chromatography를 통한 정제에, HSV-tag은 Western blotting을 통한 detection에 각각 이용할 수 있다. 또한, 이와 같이 발현된 recombinant EPSP synthase는 phosphocellulose resin에 결합하였다가 기질인 shikimate 3-phosphate와 phosphoenolpyruvate에 의해 elution되며, glyphosate에 의해 저해되는등 wildtype효소와 같은 효소 특성을 보였다.

• BMB Reports
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• 제29권3호
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• pp.183-191
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• 1996

DNA fragments, homologous to the dTDP-D-glucose 4,6-dehydratase gene, obtained from the genomic DNA of Streptomyces antibioticus $T\ddot{u}99$, a producer of the unusual macrolide antibiotic chlorothricin, were cloned and sequenced. This dehydratase gene was designated as oxil. The coding region of the oxil gene is composed of 987 bp, and analysis of the DNA sequence data reveals sequences for the gene products of 329 amino acids (molecular weight of 36,037). The deduced amino acids are 59% identical to the StrE, dTDP-D-glucose 4,6-dehydratase from the streptomycin pathway. The oxil's function was examined by expressing it in E. coli using the T7 RNA polymerase/promoter system (pRSET) to produce an active fusion protein including a his tag. This enzyme shows specificity of substrate, specific only to dTDP-D-glucose.

• Fisheries and Aquatic Sciences
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• 제25권3호
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• pp.158-166
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• 2022

The complete mitochondrial genome of Tremoctopus violaceus was sequenced to analyze its organization and phylogenetic status within the order Octopoda. The mitochondrial genome of T. violaceus had a structure and organization similar to that of other Octopoda. The content of the nucleotides A, C, G, and T was 31.68 %, 7.71 %, 20.02 %, and 40.58 %, respectively. All protein-coding genes (PCG) began with the ATG codon, excluding ND4 and ATP6, which began with ATC and ATT, respectively, and terminated with TAG, TAA, TA, or T. Codons for isoleucine were the most used codons, whereas those for arginine were used the least. Two extra tRNAs, trnN and trnL, were found in the control region. These tRNAs have a D-armless structure. The control region had excess A + T content (83.16 %) and a stem-loop structure with two elements, which is reported for the first time in Octopoda by our study. Bayesian inference using 13 PCG revealed that Octopus and Octopodidae were polyphyletic, and that Tremoctopodidae diverged relatively earlier within Octopoda. The mitochondrial genome of T. violaceus and its characteristics may help to understand the evolutionary history of Octopoda and establish a marine biodiversity conservation strategy.