• 제목/요약/키워드: Chain transfer

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有機 Halides 와 Amines 間의 光反應에 關한 硏究 (A Study on the Photoreaction between Organic Halides and Amines)

  • 김유선;박용자
    • 대한화학회지
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    • 제6권2호
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    • pp.148-154
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    • 1962
  • The reactions between organic halides$(CCl_4,\;C_6H_5Br,\;C_6H_5Cl,\;C_6H_5I)$ and amines $(C_6H_5NH_2,\;R_2NH,\;R_3N,\;(CH_2)_5NH,\;pyridine)$ were studied under mixed u.v. irradiation. The modes of reactions were examined by means of gas chromatography and product-reactant ratio determination. The reaction of $CCl_4$ with amines give chloroform and hexachloroethanes, and the reaction of aromatic halides with amines gave biphenyl and benzene. In each series of reaction there obtained mainly corresponding amine hydrohalides, but no amination products. The reactivity was in the order of the basicity of amines and of the reactivity of organic hahides, except in the case of cyclic tertiary amine. The result was interpreted as a non-chain photodecomposition process. A competitive proton abstraction reaction path via the formation of a change transfer complex was proposed as the reaction mechanism.

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Expression of Cytochrome $b_{5}$ Retropseudogenes in Hunam Blood

  • Hwang, Mi-Sun;Alan W.Steggles;Yoo, Min
    • 대한의생명과학회지
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    • 제9권3호
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    • pp.167-170
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    • 2003
  • Cytochrome $b_{5}$($b_{5}$) can be found in a variety of tissues and plays a role in the electron transfer pathways. Several retropseudogenes (numbered as I, II, II, IV, V) have been identified and well investigated for their structures. However, retropseudogene I is not clear in terms of its location on the chromosome. In addition the structure and the exression of retropseudogene V have not been confirmed. To examine the structure of bs retropseudogenes V and to see whether it is expressed in human blood we applied recombinant DNA technologies including polymerase chain reaction (PCR) and DNA sequencing. Retropseudogene V turned out to contain open reading frame (ORF) within its structure, however, no evidence of its expression was detected. Retropseudogene I was also found on the chromosome V. This study should contribute to the understanding of the structure of bs gene family.

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The Current Status and Future Outlook of Quantum Dot-Based Biosensors for Plant Virus Detection

  • Hong, Sungyeap;Lee, Cheolho
    • The Plant Pathology Journal
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    • 제34권2호
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    • pp.85-92
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    • 2018
  • Enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), widely used for the detection of plant viruses, are not easily performed, resulting in a demand for an innovative and more efficient diagnostic method. This paper summarizes the characteristics and research trends of biosensors focusing on the physicochemical properties of both interface elements and bioconjugates. In particular, the topological and photophysical properties of quantum dots (QDs) are discussed, along with QD-based biosensors and their practical applications. The QD-based Fluorescence Resonance Energy Transfer (FRET) genosensor, most widely used in the biomolecule detection fields, and QD-based nanosensor for Rev-RRE interaction assay are presented as examples. In recent years, QD-based biosensors have emerged as a new class of sensor and are expected to open opportunities in plant virus detection, but as yet there have been very few practical applications (Table 3). In this article, the details of those cases and their significance for the future of plant virus detection will be discussed.

(N-docosyl quinolinium)-TCNQ(1:2) 전하 이동 착물 Langmuir-Blodgett막의 분자 배향에 관한 연구 (A Study on the Molecular Orientation of (N-docosyl quinolinium)-TCNQ(1:2) Charge Transfer Complex Langmuir-Blodgett Films)

  • 정순욱;정회걸
    • 한국재료학회지
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    • 제10권8호
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    • pp.564-568
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    • 2000
  • Langmuir-Blodgett(LB) 법은 미래의 분자전자소자를 위한 가장 유력한 수단이며, 이러한 분자박막 소자는 그 성질이 분자는 배향에 영향을 박데 되므로 현재 새로운 물질을 이용하여 분자전자소자의 제작에 있어 관심을 모으고 있다. 본 연구에서는 (N-docosyl quinolinium)-TCNQ(1:2) 전하 이동 착물 LB 막의 분자 배향을 UV/vis 편광흡수 스펙트럼과 FT-IR transmission 및 reflection-absorption 스펙트럼의 흡수강도를 비교하여 정량적으로 평가하였다. 그 결과 TCNQ의 transition dipole moment의 각은 약 56~58。 였으며, 알킬 고리의 경사각은 약 11.1~13。였다. 제작된 Z-형 LB 막의 표면은 고압에서 중앙 높이 차가 3~4$\AA$으로 평탄하였다.

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템플릿을 이용한 자동차 프리핸드 스케치의 3D 모델로 자동변환 (Template-based Automatic 3D Model Generation from Automotive Freehand Sketch)

  • 천상욱;한순흥
    • 한국CDE학회논문집
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    • 제12권4호
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    • pp.283-297
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    • 2007
  • Seamless data integration in the CAx chain of the CAD/CAPP/CAM/CNC has been achieved to a high degree, but research concerning the transfer of data from conceptual sketches to a CAD system should be carried out further. This paper presents a method for reconstructing a 3D model from a freehand sketch. Sketch-based modeling research can be classified into gestural modeling methods and reconstructional modeling methods. This research involves the reconstructional modeling method. Here, Mitani's seminal work, designed for box-shaped 3D model using a predefined template, is improved by leveraging a relational template and specialized for automotive design. Matching between edge graphs of the relational template and the sketch is formulated and solved as the assignment problem using the feature vectors of the edges. Including the stroke preprocessing method required to generate an edge graph from a sketch, necessary procedures and relevant techniques for implementing the template-based modeling method are described. Examples from a working implementation are given.

Radical Polymerization of Vinyl Monomers to Poly(vinyl)s having nBu3Sn end Groups with Biological Activity

  • Park, Jaeyoung;Lee, Beomgi;Kim, Seongsim;Cheong, Hyeonsook;Gwak, Gyeongja;Lee, Ki Bok;Woo, Hee-Gweon
    • 통합자연과학논문집
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    • 제6권2호
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    • pp.71-75
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    • 2013
  • $Bu_3Sn$-endded poly(vinyl)s with biological activity were obtained by the radical polymerization of vinyl monomers using thianthrene cation radical/$^nBu_3H$. Thianthrene cation and stannyl radicals promoted the homopolymerization and copolymerization of styrene and ethyl vinyl ether having number average molecular weights of 2000-3100. Tributyltin hydride functions as a chain transfer agent. Such polymereization by cationic thianthrene and stannyl radicals could provide some clues for the biological reaction in living animals. Plausible polymerization mechanisms were suggested.

비이온성 계면활성제의 미셀 콜로이드에 의한 $Ca^{2+}$의 은폐에 대한 연구 (The Study for the Sequestration of $Ca^{2+}$ by the Micelle Colloid of Nonionic Sunactants)

  • 권오윤;백우현
    • 한국환경과학회지
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    • 제1권1호
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    • pp.69-76
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    • 1992
  • The effects of $Ca_{2+}$ ion on the formation of micelle colloid of nonionic surfactants, nonylphenol-(ethylene oxide)n [NP-(EO)n: n= 11, 40, 100) were investigated by the iodine solubilization method. The characteristics of spectra depended on the concentration of $Ca_{2+}$ ion and the number of EO unit. Above CMC(critical micelle concentration), the intensity of the CT (charge transfer) band by the addition of $Ca_{2+}$ ion for the NP-(EO)11 and NP-(EO)40 increased and when decreased and for the NP-(EO)In continuously increased. The increase in the intensity of CT band were attributed to the compactness of micelle in the presence of $Ca_{2+}$ ion. These phenomena may be explained by the fact that the linear ethylene oxide (EO) chain, relatively free to assume various configuration in aqueous solution, could form a pseudo-crown ether structures capable of forming complexes with $Ca_{2+}$ ion.

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한국인 분변에서 분리한 Bifidobacteria의 탈지유에서의 배양특성

  • 진효상
    • 한국미생물·생명공학회지
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    • 제25권3호
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    • pp.248-252
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    • 1997
  • Wild strains of bifidobacteria isolated from Korean feces were tested for their growth and acid production abilities in 10% skim milk. Growth of bifidobacteria was markedly decreased from the second transfer in the skim milk culture. When two strains, BF5 and BF33, were grown in skim milk with various supplements, the growth was enhanced by supplementation of 0.5% yeast extract, and 0.05% cysteine but not by short chain fatty acids. There was no enhancing effect of CO$_{2}$, substitution in the fermentor on growth. The viable cell counts of bifidobacteria, BF5 and BF33, were 9.76 and 9.98 logCFU/ml, respectively, after 30 hr cultivation and were diminished by 3 and 6 logs during storage at 5$\circ$C for 12 days.

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Polypyrrole-Glucose oxidase 효소전극의 Ethanol 첨가효과 (An Effect of Ethanol on Polypyrrole-Glucose Oxidase Enzyme Electrode)

  • 김현철;구할본;사공건
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 추계학술대회 논문집
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    • pp.147-150
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    • 1999
  • In the case of immobilizing of glucose oxidase in organic polymer using electrosynthesis, the glucose oxidase obstructs charge transfer and mass transport during the film growth. This may lead to short chained polymer and/or make charge-coupling weak between the glucose oxidase and the backbone of the polymer. That is mainly due to insulating property and net chain of the glucose oxidase. Since being the case, it is useless to increase in amount of glucose oxidase more than reasonable in the synthetic solution. We establish qualitatively that amount of immobilization can be improved by adding a little ethanol in the synthetic solution. As ethanol was added by 0.1 rnol dm" in the synthetic solution, Michaelis-Menten constants of the resulting enzyme electrode decreased from 30.7 mmol $dm^{-3}$ to about 2 mmol $dm^{-3}$. That suggests increase in affinity of the enzyme electrode for glucose and in amount of the immobilized enzyme.zyme.

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Theoretical Models of Ethylene Polymerization

  • 장만채
    • Bulletin of the Korean Chemical Society
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    • 제20권11호
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    • pp.1269-1276
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    • 1999
  • Metallocenes, whether using a cocatalyst or not, act as catalysts in ethylene polymerization. The positive charge on the transition metal of a metallocene might have an important role in polymerization as an active site in our model approach. Using semiempirical calculations in the absence of cocatalyst, we show one of the possibilities that the positive charge on a metallocene might be more easily transferred through the Cp ring of a ligand to the ethylene than to transfer directly from the transition metal to the ethylene. In these calculations, the charge on titanium in an eight C2H4 system is transferred and a polymer chain is produced. This reaction takes place only when ethylenes are arranged in a particular direction with respect to the ring, but does not take place for ethylenes near Ti or Cl atoms. The same mechanism is shown for a metallocene ligand which is sterically hindered or where the Cp ring is replaced by fluorenyl. These results suggest an entirely new polymerization mechanism in the absence of a cocatalyst in which the Cp ring is the active site.