The Experts below are selected from a list of 1875 Experts worldwide ranked by ideXlab platform

Rayna Bryaskova - One of the best experts on this subject based on the ideXlab platform.

  • sarcosine oxidase encapsulated polyvinyl alcohol silica aunp hybrid films for sarcosine sensing electrochemical bioelectrode
    Journal of The Electrochemical Society, 2014
    Co-Authors: Girish M. Kale, Rayna Bryaskova
    Abstract:

    The amperometric response of sarcosine was measured in aqueous media containing ferrocene Monocarboxylic Acid using the redox enzyme sarcosine oxidase (SOD) immobilized in a composite material based on polyvinyl alcohol (PVA) and partially prehydrolyzed tetraethyl orthosilicate (pphTEOS) at the surface of “in-house” fabricated graphite electrodes. For comparison, separate electrodes consisting of silver and gold nanoparticles (Ag/AuNPs) embedded in the PVA-pphTEOS matrix was prepared employing a novel sol-gel process based on the in situ chemical reduction of Ag or Au ions using PVA both, as a reducing agent and stabilizer. The analytical performance of the enzyme electrodes was studied in terms of linear ranges, sensitivities, response times, limits of detection, reproducibility and stability.

  • sarcosine oxidase encapsulated polyvinyl alcohol silica aunp hybrid films for sarcosine sensing electrochemical bioelectrode
    Journal of The Electrochemical Society, 2014
    Co-Authors: Girish M. Kale, Rayna Bryaskova
    Abstract:

    The amperometric response of sarcosine was measured in aqueous media containing ferrocene Monocarboxylic Acid using the redox enzyme sarcosine oxidase (SOD) immobilized in a composite material based on polyvinyl alcohol (PVA) and partially prehydrolyzed tetraethyl orthosilicate (pphTEOS) at the surface of “in-house” fabricated graphite electrodes. For comparison, separate electrodes consisting of silver and gold nanoparticles (Ag/AuNPs) embedded in the PVA-pphTEOS matrix was prepared employing a novel sol-gel process based on the in situ chemical reduction of Ag or Au ions using PVA both, as a reducing agent and stabilizer. The analytical performance of the enzyme electrodes was studied in terms of linear ranges, sensitivities, response times, limits of detection, reproducibility and stability.

Girish M. Kale - One of the best experts on this subject based on the ideXlab platform.

  • sarcosine oxidase encapsulated polyvinyl alcohol silica aunp hybrid films for sarcosine sensing electrochemical bioelectrode
    Journal of The Electrochemical Society, 2014
    Co-Authors: Girish M. Kale, Rayna Bryaskova
    Abstract:

    The amperometric response of sarcosine was measured in aqueous media containing ferrocene Monocarboxylic Acid using the redox enzyme sarcosine oxidase (SOD) immobilized in a composite material based on polyvinyl alcohol (PVA) and partially prehydrolyzed tetraethyl orthosilicate (pphTEOS) at the surface of “in-house” fabricated graphite electrodes. For comparison, separate electrodes consisting of silver and gold nanoparticles (Ag/AuNPs) embedded in the PVA-pphTEOS matrix was prepared employing a novel sol-gel process based on the in situ chemical reduction of Ag or Au ions using PVA both, as a reducing agent and stabilizer. The analytical performance of the enzyme electrodes was studied in terms of linear ranges, sensitivities, response times, limits of detection, reproducibility and stability.

  • sarcosine oxidase encapsulated polyvinyl alcohol silica aunp hybrid films for sarcosine sensing electrochemical bioelectrode
    Journal of The Electrochemical Society, 2014
    Co-Authors: Girish M. Kale, Rayna Bryaskova
    Abstract:

    The amperometric response of sarcosine was measured in aqueous media containing ferrocene Monocarboxylic Acid using the redox enzyme sarcosine oxidase (SOD) immobilized in a composite material based on polyvinyl alcohol (PVA) and partially prehydrolyzed tetraethyl orthosilicate (pphTEOS) at the surface of “in-house” fabricated graphite electrodes. For comparison, separate electrodes consisting of silver and gold nanoparticles (Ag/AuNPs) embedded in the PVA-pphTEOS matrix was prepared employing a novel sol-gel process based on the in situ chemical reduction of Ag or Au ions using PVA both, as a reducing agent and stabilizer. The analytical performance of the enzyme electrodes was studied in terms of linear ranges, sensitivities, response times, limits of detection, reproducibility and stability.

Jie Dai - One of the best experts on this subject based on the ideXlab platform.

  • supramolecular and redox chemistry of tetrathiafulvalene Monocarboxylic Acid with hydrogen bonded pyridine and bipyridine molecules
    Journal of Physical Chemistry B, 2012
    Co-Authors: Qinyu Zhu, Qionghua Han, Mingyan Shao, Zheng Shi, Jie Dai
    Abstract:

    Although tetrathiafulvalene derivatives (TTFs) have been used as the redox-active unit in a lot of ion responsive receptors, only a few such examples of TTF carboxylic Acids have been reported, especially about the responses to neutral organic molecules. In this work, electrochemical and spectral properties of dimethylthio-tetrathiafulvalene Monocarboxylic Acid (DMT-TTFCOOH) have been studied by both experimental methods and quantum chemical calculations. A square mechanism of proton transfer and electron transfer equilibriums was proposed. It is noteworthy that the process of oxidizing the TTF moiety of DMT-TTFCOOH could be controlled to obtain TTF•+ radical cation or TTF2+ dication by choosing suitable oxidizing reagents. Supramolecular responsive properties of DMT-TTFCOOH to py/bpy were investigated by cyclic voltammetry and 1H NMR spectra. The results showed that the compound DMT-TTFCOOH is an electrochemically sensitive hydrogen bonding donor that can detect a tiny difference in the hydrogen bonding ...

Leslie Z Benet - One of the best experts on this subject based on the ideXlab platform.

  • functional characterization of Monocarboxylic Acid large neutral amino Acid bile Acid and peptide transporters and p glycoprotein in mdck and caco 2 cells
    Journal of Pharmaceutical Sciences, 2002
    Co-Authors: Wendy S Putnam, Srinivasan Ramanathan, Lin Pan, Lori H Takahashi, Leslie Z Benet
    Abstract:

    Bidirectional transport studies were conducted to determine whether substrates of five intestinal transporters showed carrier-mediated asymmetric transport across MDCK (Madin-Darby canine kidney) cell monolayers grown under standard conditions. Drug concentrations were quantitated using liquid scintillation counting, liquid chromatography/mass spectrometry/mass spectrometry, or liquid chromatography/mass spectrometry. In the presence of a pH gradient, benzoic Acid exhibited net apical-to-basolateral transport, with apparent permeability ratios (apical-to-basolateral permeability/basolateral-to-apical permeability) ranging from 14 to 25. The addition of valproic Acid reduced the permeability ratio by 70-90%. Cephalexin transport also exhibited net absorption in the presence of a pH gradient, with apparent permeability ratios ranging from 14 to 71, depending on growth conditions. Radiolabeled phenylalanine exhibited a low level of carrier-mediated absorption with an apparent permeability ratio of 1.8 that was reduced to 1.0 in the presence of unlabeled L-phenylalanine. Taurocholic Acid did not exhibit carrier-mediated absorption. Cyclosporine and fexofenadine exhibited P-glycoprotein-mediated efflux from both MDCK and Caco-2 cells, which was more sensitive to inhibition in MDCK cells. These results suggest that although MDCK cell monolayers may be a useful model for evaluating transport by the absorptive Monocarboxylic Acid and peptide transporters and the efflux transporter, P-glycoprotein, they are not useful for predicting large neutral amino Acid or bile Acid transport in the intestine.

  • functional characterization of Monocarboxylic Acid large neutral amino Acid bile Acid and peptide transporters and p glycoprotein in mdck and caco 2 cells
    Journal of Pharmaceutical Sciences, 2002
    Co-Authors: Wendy S Putnam, Srinivasan Ramanathan, Lori H Takahashi, Leslie Z Benet
    Abstract:

    ABSTRACT: Bidirectional transport studies were conducted to determine whether substrates of five intestinal transporters showed carrier-mediated asymmetric transport across MDCK (Madin-Darby canine kidney) cell monolayers grown under standard conditions. Drug concentrations were quantitated using liquid scintillation counting, liquid chromatography/mass spectrometry/mass spectrometry, or liquid chromatography/mass spectrometry. In the presence of a pH gradient, benzoic Acid exhibited net apical-to-basolateral transport, with apparent permeability ratios (apical-to-basolateral permeability/basolateral-to-apical permeability) ranging from 14 to 25. The addition of valproic Acid reduced the permeability ratio by 70–90%. Cephalexin transport also exhibited net absorption in the presence of a pH gradient, with apparent permeability ratios ranging from 14 to 71, depending on growth conditions. Radiolabeled phenylalanine exhibited a low level of carrier-mediated absorption with an apparent permeability ratio of 1.8 that was reduced to 1.0 in the presence of unlabeled L -phenylalanine. Taurocholic Acid did not exhibit carrier-mediated absorption. Cyclosporine and fexofenadine exhibited P-glycoprotein–mediated efflux from both MDCK and Caco-2 cells, which was more sensitive to inhibition in MDCK cells. These results suggest that although MDCK cell monolayers may be a useful model for evaluating transport by the absorptive Monocarboxylic Acid and peptide transporters and the efflux transporter, P-glycoprotein, they are not useful for predicting large neutral amino Acid or bile Acid transport in the intestine. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association

Martin Pumera - One of the best experts on this subject based on the ideXlab platform.

  • 3d printed graphene polylactic Acid electrodes promise high sensitivity in electroanalysis
    Analytical Chemistry, 2018
    Co-Authors: Lorena Manzanares C. Palenzuela, Filip Novotný, Petr Krupicka, Zdeněk Sofer, Martin Pumera
    Abstract:

    Additive manufacturing provides a unique tool for prototyping structures toward electrochemical sensing, due to its ability to produce highly versatile, tailored-shaped devices in a low-cost and fast way with minimized waste. Here we present 3D-printed graphene electrodes for electrochemical sensing. Ring- and disc-shaped electrodes were 3D-printed with a Fused Deposition Modeling printer and characterized using cyclic voltammetry and scanning electron microscopy. Different redox probes K3Fe(CN)6:K4Fe(CN)6, FeCl3, ascorbic Acid, Ru(NH3)6Cl3, and ferrocene Monocarboxylic Acid) were used to assess the electrochemical performance of these devices. Finally, the electrochemical detection of picric Acid and ascorbic Acid was carried out as proof-of-concept analytes for sensing applications. Such customizable platforms represent promising alternatives to conventional electrodes for a wide range of sensing applications.

  • 3D-Printed Graphene/Polylactic Acid Electrodes Promise High Sensitivity in Electroanalysis
    2018
    Co-Authors: Lorena Manzanares C. Palenzuela, Filip Novotný, Petr Krupička, Zdeněk Sofer, Martin Pumera
    Abstract:

    Additive manufacturing provides a unique tool for prototyping structures toward electrochemical sensing, due to its ability to produce highly versatile, tailored-shaped devices in a low-cost and fast way with minimized waste. Here we present 3D-printed graphene electrodes for electrochemical sensing. Ring- and disc-shaped electrodes were 3D-printed with a Fused Deposition Modeling printer and characterized using cyclic voltammetry and scanning electron microscopy. Different redox probes K3Fe­(CN)6:K4Fe­(CN)6, FeCl3, ascorbic Acid, Ru­(NH3)6Cl3, and ferrocene Monocarboxylic Acid) were used to assess the electrochemical performance of these devices. Finally, the electrochemical detection of picric Acid and ascorbic Acid was carried out as proof-of-concept analytes for sensing applications. Such customizable platforms represent promising alternatives to conventional electrodes for a wide range of sensing applications