The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Yoshio Okahata - One of the best experts on this subject based on the ideXlab platform.

  • Small Mass-Change Detectable Quartz Crystal Microbalance and Its Application to Enzymatic One-Base Elongation on DNA
    2016
    Co-Authors: Hiroshi Yoshimine, Hiroyuki Furusawa, Taisuke Kojima, Yoshio Okahata
    Abstract:

    A highly sensitive 27 MHz Quartz Crystal Microbalance instrument with an automatic flow injection system was developed to obtain realistic minimal frequency noise (±0.05 Hz) and to obtain a stable signal baseline (±1 Hz/h) by controlling the temperature of each part in the Quartz Crystal Microbalance (QCM) system using three Peltier devices with a resolution of ±0.001 °C and by optimizing the flow system to prevent fluctuation of the internal pressure of the QCM. The improved QCM with an automatic flow injection system enabled detection of small mass changes such as binding of biotin to a streptavidin-immobilized QCM with a high signal-to-noise ratio. We also applied this device to enzyme reactions of one-base elongation by DNA polymerase (Klenow fragment, KF). We immobilized dsDNAs including the protruding end of dA, dG, dT, or dC on the QCM electrode and ran complementary dNTP monomers with KF into the QCM flow cell. We could directly detect the enzymatic one-base elongation of DNA as a small mass increase, and we found the difference in the reaction rate for each monomer

  • real time monitoring of cell free translation on a Quartz Crystal Microbalance
    Journal of the American Chemical Society, 2009
    Co-Authors: Shuntaro Takahashi, Hiroyuki Furusawa, Masaaki Iida, Yoshihiro Shimizu, Takuya Ueda, Yoshio Okahata
    Abstract:

    The efficiency of protein synthesis is often regulated post-transcriptionally by sequences within the mRNA. To investigate the reactions of protein translation, we established a system that allowed real-time monitoring of protein synthesis using a cell-free translation mixture and a 27 MHz Quartz-Crystal Microbalance (QCM). Using an mRNA that encoded a fusion polypeptide comprising the streptavidin-binding peptide (SBP) tag, a portion of Protein D as a spacer, and the SecM arrest sequence, we could follow the binding of the SBP tag, while it was displayed on the 70S ribosome, to a streptavidin-modified QCM over time. Thus, we could follow a single turnover of protein synthesis as a change in mass. This approach allowed us to evaluate the effects of different antibiotics and mRNA sequences on the different steps of translation. From the results of this study, we have determined that both the formation of the initiation complex from the 70S ribosome, mRNA, and fMet−tRNAfMet and the accommodation of the seco...

  • Added mass effect on immobilizations of proteins on a 27 MHz Quartz Crystal Microbalance in aqueous solution.
    Analytical chemistry, 2009
    Co-Authors: Hiroyuki Furusawa, Tomomitsu Ozeki, Mizuki Morita, Yoshio Okahata
    Abstract:

    During the immobilization process of proteins onto an Au-surface of a 27 MHz Quartz Crystal Microbalance (QCM) in aqueous solutions, apparent large frequency changes (ΔFwater) were observed compare...

  • monitoring of ecorv digestions on a dna immobilized Quartz Crystal Microbalance
    Chemistry Letters, 2007
    Co-Authors: Shuntaro Takahashi, Hiroyuki Furusawa, Hisao Matsuno, Yoshio Okahata
    Abstract:

    Kinetic parameters of DNA digestions by EcoRV such as binding and dissociation rate constants of enzymes to DNA (<:on and k off ) and the site-specific cleavage reaction (k cat ) could be obtained using a DNA-immobilized Quartz-Crystal Microbalance (QCM).

  • kinetic measurements of dna hybridization on an oligonucleotide immobilized 27 mhz Quartz Crystal Microbalance
    Analytical Chemistry, 1998
    Co-Authors: Yoshio Okahata, Masanori Kawase, Fuyuka Ohtake, Hiroyuki Furusawa, Kenichi Niikura, Yasuhito Ebara
    Abstract:

    A highly sensitive 27-MHz Quartz-Crystal Microbalance, on which a 10−30-mer oligonucleotide was immobilized as a probe molecule, was employed to detect hybridization of complementary oligonucleotides in aqueous solution. From frequency decreases (mass increases due to the hybridization) with passage of time, kinetic parameters such as association constants (Ka) and binding and dissociation rate constants (k1 and k-1) could be obtained, as well as binding (hybridization) amount at the nanogram level (Δm). Kinetic studies were carried out by changing various parameters:  (i) the immobilization method of a probe oligonucleotide on Au electrode, (ii) number of mismatching bases in sequences of target oligonucleotides, (iii) length of both probe and target oligonucleotides, (iv) hybridization temperature, and (v) ionic strength in solution. The obtained results were compared with those obtained by a surface plasmon resonance method using a BIAcore system.

Guangzhong Xie - One of the best experts on this subject based on the ideXlab platform.

  • a room temperature supramolecular based Quartz Crystal Microbalance qcm methane gas sensor
    Sensors and Actuators B-chemical, 2009
    Co-Authors: Yadong Jiang, Ping Sun, Guangzhong Xie
    Abstract:

    A supramolecular cryptophane-A-based Quartz Crystal Microbalance (QCM) gas sensor has been developed. Supramolecular cryptophane-A was synthesized from vanillyl alcohol using a double trimerisation method and deposited on a QCM device via electrospray method. The sensor was exposed to various concentrations of CH4 gas and other gases operated at different temperatures. The influence of humidity was also examined. The sensor’s response showed that it is selective to methane gas. A fast response and recovery was observed at room temperature. Detection limit for methane is 0.05% (v/v). The mechanism of the interactions between CH4 gas and cryptophane-A was discussed preliminarily.

  • polymer coated sensor array based on Quartz Crystal Microbalance for chemical agent analysis
    European Polymer Journal, 2008
    Co-Authors: Zhihua Ying, Yadong Jiang, Guangzhong Xie, Huiling Tai
    Abstract:

    Quartz Crystal Microbalance (QCM) gas sensors based on polymeric material were fabricated and their gas response characteristics were examined for four simulant gases of chemical agents, which were dimethyl methyl phosphonate (DMMP), N,N-dimethylacetamide (DMA), 1,5-dichloropentane (DCP) and dichloroethane (DCE). For the selection of appropriate coating materials, both principal component analysis (PCA) and hierarchical cluster methods were applied to a data set collected from 15 QCM sensors for 12 analytes. Four appropriate coating materials were selected after optimizing the correlation between the 15 coating materials and the first four principal component (PC) factors. The four chosen polymers were used as sensitive component for a sensor array, and then PCA is adapted to classify four simulant gases. The results show that the QCM sensor array has high sensitivity and selectivity to four chemical agents.

  • pvdf coated Quartz Crystal Microbalance sensor for dmmp vapor detection
    Sensors and Actuators B-chemical, 2007
    Co-Authors: Zhihua Ying, Yadong Jiang, Guangzhong Xie, Hua Wang
    Abstract:

    Abstract A Quartz Crystal Microbalance (QCM) modified with poly(vinylidene fluoride) (PVDF) was fabricated and used for detection of dimethyl methylphosphonate (DMMP) vapor, a simulant of nerve agents using a drop-coating method. Measurements were based on the frequency shifts due to the adsorption of DMMP vapor on the surface of the modified electrodes. It was found that frequency shifts were linear to the concentrations of analyte in the range of 5–60 ppm with a correlation coefficient of above 0.997. The influences of temperature and humidity on the sensors were also examined. Results showed that the sensitivity to DMMP vapor was almost identical in various humidity circumstances, and the sensitivity was higher in a lower temperature range.

Hiroyuki Furusawa - One of the best experts on this subject based on the ideXlab platform.

  • Small Mass-Change Detectable Quartz Crystal Microbalance and Its Application to Enzymatic One-Base Elongation on DNA
    2016
    Co-Authors: Hiroshi Yoshimine, Hiroyuki Furusawa, Taisuke Kojima, Yoshio Okahata
    Abstract:

    A highly sensitive 27 MHz Quartz Crystal Microbalance instrument with an automatic flow injection system was developed to obtain realistic minimal frequency noise (±0.05 Hz) and to obtain a stable signal baseline (±1 Hz/h) by controlling the temperature of each part in the Quartz Crystal Microbalance (QCM) system using three Peltier devices with a resolution of ±0.001 °C and by optimizing the flow system to prevent fluctuation of the internal pressure of the QCM. The improved QCM with an automatic flow injection system enabled detection of small mass changes such as binding of biotin to a streptavidin-immobilized QCM with a high signal-to-noise ratio. We also applied this device to enzyme reactions of one-base elongation by DNA polymerase (Klenow fragment, KF). We immobilized dsDNAs including the protruding end of dA, dG, dT, or dC on the QCM electrode and ran complementary dNTP monomers with KF into the QCM flow cell. We could directly detect the enzymatic one-base elongation of DNA as a small mass increase, and we found the difference in the reaction rate for each monomer

  • real time monitoring of cell free translation on a Quartz Crystal Microbalance
    Journal of the American Chemical Society, 2009
    Co-Authors: Shuntaro Takahashi, Hiroyuki Furusawa, Masaaki Iida, Yoshihiro Shimizu, Takuya Ueda, Yoshio Okahata
    Abstract:

    The efficiency of protein synthesis is often regulated post-transcriptionally by sequences within the mRNA. To investigate the reactions of protein translation, we established a system that allowed real-time monitoring of protein synthesis using a cell-free translation mixture and a 27 MHz Quartz-Crystal Microbalance (QCM). Using an mRNA that encoded a fusion polypeptide comprising the streptavidin-binding peptide (SBP) tag, a portion of Protein D as a spacer, and the SecM arrest sequence, we could follow the binding of the SBP tag, while it was displayed on the 70S ribosome, to a streptavidin-modified QCM over time. Thus, we could follow a single turnover of protein synthesis as a change in mass. This approach allowed us to evaluate the effects of different antibiotics and mRNA sequences on the different steps of translation. From the results of this study, we have determined that both the formation of the initiation complex from the 70S ribosome, mRNA, and fMet−tRNAfMet and the accommodation of the seco...

  • Added mass effect on immobilizations of proteins on a 27 MHz Quartz Crystal Microbalance in aqueous solution.
    Analytical chemistry, 2009
    Co-Authors: Hiroyuki Furusawa, Tomomitsu Ozeki, Mizuki Morita, Yoshio Okahata
    Abstract:

    During the immobilization process of proteins onto an Au-surface of a 27 MHz Quartz Crystal Microbalance (QCM) in aqueous solutions, apparent large frequency changes (ΔFwater) were observed compare...

  • monitoring of ecorv digestions on a dna immobilized Quartz Crystal Microbalance
    Chemistry Letters, 2007
    Co-Authors: Shuntaro Takahashi, Hiroyuki Furusawa, Hisao Matsuno, Yoshio Okahata
    Abstract:

    Kinetic parameters of DNA digestions by EcoRV such as binding and dissociation rate constants of enzymes to DNA (<:on and k off ) and the site-specific cleavage reaction (k cat ) could be obtained using a DNA-immobilized Quartz-Crystal Microbalance (QCM).

  • kinetic measurements of dna hybridization on an oligonucleotide immobilized 27 mhz Quartz Crystal Microbalance
    Analytical Chemistry, 1998
    Co-Authors: Yoshio Okahata, Masanori Kawase, Fuyuka Ohtake, Hiroyuki Furusawa, Kenichi Niikura, Yasuhito Ebara
    Abstract:

    A highly sensitive 27-MHz Quartz-Crystal Microbalance, on which a 10−30-mer oligonucleotide was immobilized as a probe molecule, was employed to detect hybridization of complementary oligonucleotides in aqueous solution. From frequency decreases (mass increases due to the hybridization) with passage of time, kinetic parameters such as association constants (Ka) and binding and dissociation rate constants (k1 and k-1) could be obtained, as well as binding (hybridization) amount at the nanogram level (Δm). Kinetic studies were carried out by changing various parameters:  (i) the immobilization method of a probe oligonucleotide on Au electrode, (ii) number of mismatching bases in sequences of target oligonucleotides, (iii) length of both probe and target oligonucleotides, (iv) hybridization temperature, and (v) ionic strength in solution. The obtained results were compared with those obtained by a surface plasmon resonance method using a BIAcore system.

Ziqiang Zhu - One of the best experts on this subject based on the ideXlab platform.

  • humidity detection by nanostructured zno a wireless Quartz Crystal Microbalance investigation
    Sensors and Actuators A-physical, 2007
    Co-Authors: Xiaofeng Zhou, Jian Zhang, Tao Jiang, Xiaohua Wang, Ziqiang Zhu
    Abstract:

    In this paper, we present a wireless relative humidity sensor system prototype which based on Quartz Crystal Microbalance (QCM) coated with nanostructured ZnO as sensing element. The wireless QCM sensor system is composed of two parts: the probe based on QCM sensor and the RF receiver. The probe has two functions: to sense and display the frequency signals and to transmit the signals to the receiver. The receiver connected to the personal computer can receive and record the sensor signals. Experimental results indicate that the wireless RH sensor has quite good stability and reproducibility. The interaction distance between the probe and the receiver can be varied from 5 to 300 m. The proposed system is potential to construct the low-cost, real-time online wireless gas sensor system, which can be used to monitor the pollutants in the family and the harsh environment.

  • ammonia sensing characteristics of zno nanowires studied by Quartz Crystal Microbalance
    Applied Surface Science, 2006
    Co-Authors: Xiaohua Wang, Jian Zhang, Ziqiang Zhu
    Abstract:

    Abstract The ZnO nanowires have been prepared and studied as the sensing element for the detection of ammonia. The ZnO nanowires were first synthesized by evaporating high purity zinc pellets at 900 °C and then distributed onto the electrode surfaces of Quartz Crystals at room temperatures. Gas sensitive properties of ZnO nanowires layer were studied in terms of the Quartz Crystal Microbalance (QCM) at room temperature. It is found that the obtained response of the sensors varied with the thickness of the ZnO nanowires layer. ZnO nanowires showed high sensitivity to ammonia in the range of 40–1000 ppm. The response time of the sensor was as fast as ∼5 s at any concentration (40–1000 ppm) of ammonia gas. The ZnO nanowires-coated sensors have a good frequency stability and reproducibility. All results demonstrated that the ZnO nanowire was a potential gas sensing material for practical use.

  • Quartz Crystal Microbalance coated with carbon nanotube films used as humidity sensor
    Sensors and Actuators A-physical, 2005
    Co-Authors: Yongsheng Zhang, Desheng Jiang, Laiqiang Luo, Ziqiang Zhu
    Abstract:

    Abstract The possibilities and properties of multi-wall carbon nanotube (MWNT)-coated Quartz Crystal Microbalance (QCM) as a humidity sensor are presented. In order to enhance effectively sensitivity of the sensor, the MWNTs coated on QCM are treated by means of ball milling and hydrogen plasma technique, respectively. The morphology and microstructure of MWNT films were characterized with SEM and TEM. It can be found that the frequency shift of the MWNT-coated QCM linearly decreases with increasing relative humidity over the range of 5–97% RH. The sensors have a response and recovery time of about 60 and 70 s, respectively. The experimental results prove that MWNT-coated QCM are usable as a humidity sensor and as an analytical device.

Joachim Maier - One of the best experts on this subject based on the ideXlab platform.