• 제목/요약/키워드: time-of-flight (TOF)

검색결과 410건 처리시간 0.031초

A Simple and Rapid Method to Isolate Low Molecular Weight Proteinase Inhibitors from Soybean

  • Krishnan Bari B.
    • 한국작물학회지
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    • 제49권4호
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    • pp.342-348
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    • 2004
  • Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the $60\%$ isopropanol extract of soybean(Glycine max [L.] Merr.) seed revealed two abundant proteins with molecular masses of 19 and 10 kDa. Amino acid analysis revealed that the isopropanol-extractable protein fraction was rich in cysteine. Two-dimensional gel electro-phoretic analysis indicated that the 19kDa and 10kDa proteins had pI of 4.2 and 4.0 respectively. Peptide mass fingerprints of trypsin digests of the two proteins obtained using matrix-assisted, laser desorption/ionization-time of flight (MALDI-TOF) mass spectroscopy revealed the 19kDa protein was Kunitz trypsin inhibitor and the 10kDa protein was Bowman-Birk proteinase inhibitor. When resolved under non-denaturing conditions, the isopropanol-extracted proteins inhibited trypsin and chymotrypsin activity. Results presented in this study demonstrate that isopropanol extraction of soybean seed could be used as a simple and rapid method to obtain a protein fraction enriched in Kunitz trypsin and Bowman-Birk proteinase inhibitors. Since proteinase inhibitors are rich in sulfur amino acids and are putative anticarcinogens, this rapid and inexpensive isolation procedure could facilitate efforts in nutrition and cancer research.

MCS-BEq 알고리즘에 의한 $SF_6-Ar$ 혼합기체의 확산계수 (Diffusion Coefficients in $SF_6-Ar$ Gas used by MCS-BE Algorithm)

  • 김상남
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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    • pp.298-301
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    • 2006
  • This paper describes the electron energy distribution function characteristics in $SF_6-Ar$ gas calculated for range of E/N values from $50\sim700[Td]$ by the Monte Carlo simulation(MCS) and Boltzmann equation(BE) method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by time of flight(TOF) method. In this dissertation the results of the combined experimental and theoretical studies designed to understand and predict the spatial growth and transport coefficients for electrons in $SF_6$ and $SF_6-Ar$ mixtures have described. The ionization and attachment coefficients in pure $SF_6$ and $SF_6-Ar$ mixtures have been calculated over the range of 10$SF_6$ molecule and for Ar atom proposed by other authors. The results obtained in this work will provide valuable information on the fundamental behaviors of electrons in weakly ionized gases and the role of electron attachment in the choice of better gases and unitary gas dielectrics or electro negative components in dielectric gas mixtures.

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Organic matrix-free imaging mass spectrometry

  • Kim, Eunjin;Kim, Jisu;Choi, Inseong;Lee, Jeongwook;Yeo, Woon-Seok
    • BMB Reports
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    • 제53권7호
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    • pp.349-356
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    • 2020
  • Mass spectrometry (MS) is an ideal tool for analyzing multiple types of (bio)molecular information simultaneously in complex biological systems. In addition, MS provides structural information on targets, and can easily discriminate between true analytes and background. Therefore, imaging mass spectrometry (IMS) enables not only visualization of tissues to give positional information on targets but also allows for molecular analysis of targets by affording the molecular weights. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS is particularly effective and is generally used for IMS. However, the requirement for an organic matrix raises several limitations that get in the way of accurate and reliable images and hampers imaging of small molecules such as drugs and their metabolites. To overcome these problems, various organic matrix-free LDI IMS systems have been developed, mostly utilizing nanostructured surfaces and inorganic nanoparticles as an alternative to the organic matrix. This minireview highlights and focuses on the progress in organic matrix-free LDI IMS and briefly discusses the use of other IMS techniques such as desorption electrospray ionization, laser ablation electrospray ionization, and secondary ion mass spectrometry.

Structural Characterization of Non-reducing Oligosaccharide Produced by Arthrobacter crystallopoietes N-08

  • Bae, Bum-Sun;Shin, Kwang-Soon;Lee, Ho
    • Food Science and Biotechnology
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    • 제18권2호
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    • pp.519-525
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    • 2009
  • A bacterial strain (Strain N-08) capable of extracellularly producing high level of non-reducing oligosaccharide (NR-OS) isolated from soil. The strain was identified phylogenetically by 16S rDNA sequence analysis and found to be very close to Arthrobacter crystallopoietes. The high production of NR-OS was observed in the basal culture medium containing maltose as a sole carbon source. The NR-OS in culture supernatant was purified by glucoamylase treatment and Dowex-1 (OH.) ion exchange chromatography and its structure was characterized. This oligosaccharide consisted of only glucose. Methylation analysis indicated that this fraction was composed mainly of non-reducing terminal glucopyranoside. Matrixassisted laser-induced/ionization time-of-flight (MALDI-TOF) and electrospray ionization-mass spectrometry (ESI-MS)/MS analyses suggested that this oligosaccharide comprised non-reducing disaccharide unit with 1,1-glucosidic linkage. When this disaccharide was analyzed by $^1H$-NMR and $^{13}C$-NMR, it gave the same signals with $\alpha$-D-glucopyranosyl-(1,1)-$\alpha$-Dglucopyranoside. These results indicated that the NR-OS produced by A. crystallopoietes N-08 was ${\alpha}1$,${\alpha}1$-trehalose. This is the first report of the trehalose which can be produced directly from maltose by A. crystallopoietes N-08.

비정질 하프늄인듐징크옥사이드 산화물 반도체의 공정 파워에 따른 트랜지스터의 전기적 특성 연구 (Study on the Electrical Properties of Amorphous HfInZnO TFTs Depending on Sputtering Power)

  • 유동윤;정유진;김도형;주병권;이상렬
    • 한국전기전자재료학회논문지
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    • 제24권8호
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    • pp.674-677
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    • 2011
  • The dependency of sputtering power on the electrical performances in amorphous HIZO-TFT (hafnium-indium-zinc-oxide thin film transistors) has been investigated. The HIZO channel layers were prepared by using radio frequency (RF) magnetron sputtering method with different sputtering power at room temperature. TOF-SIMS (time of flight secondary ion mass spectrometry) was performed to confirm doping of hafnium atom in IZO film. The field effect mobility (${\mu}FE$) increased and threshold voltage ($V_{th}$) shifted to negative direction with increasing sputtering power. This result can be attributed to the high energy particles knocking-out oxygen atoms. As a result, oxygen vacancies generated in HIZO channel layer with increasing sputtering power resulted in negative shift in Vth and increase in on-current.

Proteomic Dissection of Abiotic Stress Response in Crop Plants

  • Alam, Iftekhar;Sharmin, Shamima Akhtar;Lee, Byung-Hyun
    • 한국환경농학회:학술대회논문집
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    • 한국환경농학회 2011년도 30주년 정기총회 및 국제심포지엄
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    • pp.196-204
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    • 2011
  • Abiotic stress is the primary cause of crop loss worldwide, reducing average yields for most major crop plants by more than 50%. In addition, future agricultural production and management will encounter multifaceted challenges from global climate change. Therefore, it is necessary to study the molecular response of crop plants to the stresses in order to develop appropriate strategies to sustain food production under adverse environmental conditions. We carried out a large scale proteomic analysis of soybean plants in response to various abiotic stresses, including drought, salinity, waterlogging and their interactions. Proteins were analyzed by two dimensional polyacrylamide gel electrophoresis followed by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. The identified proteins are involved in a wide range of cellular functions. In addition to the well known stress-associated proteins, we identified several novel proteins, which were not reported before. In many cases our proteomic data bridges the gap between mRNA and metabolite data. Our studie provides new insights into identification of abiotic stress responsive proteins in soybean, and demonstrates the advantages of proteomic analysis in dissecting metabolic and regulatory networks.

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강 구조물 접합부의 건전성 감시를 위한 램 웨이브와 확률 신경망의 적용 (Application of Lamb Waves and Probabilistic Neural Networks for Health Monitoring of Joint Steel Structures)

  • 박승희;이종재;윤정방;노용래
    • 한국소음진동공학회논문집
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    • 제15권1호
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    • pp.53-62
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    • 2005
  • This study presents the NDE (non-destructive evaluation) technique for detecting the loosened bolts on joint steel structures on the basis of TOF (time of flight) and amplitudes of Lamb waves. Probabilistic neural network (PNN) technique which is an effective tool for pattern classification problem was applied to the damage estimation using PZT induced Lamb waves. Two kinds of damages were introduced by dominant damages (DD) which mean loosened bolts within the Lamb waves beam width and minor damages (MD) which mean loosened bolts out of the Lamb waves beam width. They were investigated for the establishment of the optimal decision boundaries which divide each damage class's region including the intact class. In this study, the applicability of the probabilistic neural networks was identified through the test results for the damage cases within and out of wave beam path. It has been found that the present methods are very efficient and reasonable in predicting the loosened bolts on the joint steel structures probabilistically.

홍어류(Dipturus chilensis) 껍질로부터 분리 정제된 collagenase-1 저해 펩타이드의 특성 (Characterization of a Collagenase-1 Inhibitory Peptide Purified from Skate Dipturus chilensis Skin)

  • 박성하;이정권;전중균;변희국
    • 한국수산과학회지
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    • 제44권5호
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    • pp.456-463
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    • 2011
  • We attempted to isolate a collagenase-1 inhibitory peptide from skate Dipturus chilensis skin protein. The protein from skate skin was digested by various enzymes (alcalase, ${\alpha}$-chymotrypsin, neutrase, papain, pepsin, and trypsin) to produce a collagenase-1 inhibitory peptide. The collagenase-1 inhibitory activity of the peptides obtained was measured by gelatin digestion assay. Among the six hydrolysates, pepsin hydrolysate exhibited the highest collagenase-1 inhibitory activity. The peptide showing strong collagenase-1 inhibitory activity was purified by Sephadex G-25 gel chromatography and HPLC using an octadecylsilyls (ODS) column. The amino acid sequence of purified collagenase-1 inhibitory peptide was identified to be Asn-Leu-Asp-Val -Leu-Glu-Val-Phe (961 Da) by quadrupole time of flight (Q-TOF) and electrospray ionization mass spectrometry (ESI-MS) mass spectroscopy. The $IC_{50}$ value of purified peptide was 87.0 ${\mu}M$. Moreover, the peptide did not exhibit cytotoxic effects on human dermal fibroblast cell lines.

$e^-$-$CF_4$산란중에서 전자군의 확산계수 및 에너지분포함수 연구 (Analysis of Electron Swarm Diffusion Coefficients and Energy Distribution Function in $e^-$-$CF_4$ Scattering)

  • 하성철;임상원
    • E2M - 전기 전자와 첨단 소재
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    • 제10권4호
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    • pp.342-348
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    • 1997
  • In this paper, the behavior of electron swarm parameters and energy distribution function of the discharge under high E/N condition in e$^{-10}$ -CF$_{4}$ gas have been analysed over the E/N range from 1-300(Td) by the MCS and BEq methods using set of electron collision cross section determined by the authors. The swarm parameters and energy distribution function have been calculated for the pulsed Townsend, steady-state Townsend and Time of Flight methods. The results gained that the value of electron swarm parameters such as the electron drift velocity, the electron ionization and attachment coefficients and longitudinal diffusion coefficients in agreement with the experimental and theoretical data for a range of E/N. The electron energy distribution function has been explained and analysed in e$^{-10}$ -CF$_{4}$ at E/N : 5, 10, 100, 200, 300(Td) for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The validity of the results has been confirmed by TOF and SST methods.

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강 구조물 접합부의 건전성 감시를 위한 램 웨이브와 확률 신경망의 적용 (Application of Lamb Waves and Probabilistic Neural Networks for Health Monitoring of Joint Steel Structures)

  • 박승희;이종재;윤정방;노용래
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.625-632
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    • 2004
  • This study presents the NDE (non-destructive evaluation) technique for detecting the loosened bolts on joint steel structures on the basis of TOF (time of flight) and amplitudes of Lamb waves. Probabilistic neural network (PNN) technique which is an effective tool for pattern classification problem was applied to the damage estimation using PZT induced Lamb waves. Two kinds of damages were introduced by dominant damages (DD) which mean loosened bolts within the Lamb waves beam width and minor damages (MD) which mean loosened bolts out of the Lamb waves beam width. They were investigated for the establishment of the optimal decision boundaries which divide each damage class's region including the intact class. In this study, the applicability of the probabilistic neural networks was identified through the test results for the damage cases within and out of wave beam path. It has been found that the present methods are very efficient and reasonable in predicting the loosened bolts on the joint steel structures probabilistically.

  • PDF