Voltammetric Studies of Anion Transfer Reactions Across a Microhole Array-Water/PVC-NPOE Gel Interface

Hossain, Md. Mokarrom,Girault, Hubert H.,Lee, Hye-Jin Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.5

Voltammetric characterization of hydrophilic anion transfer processes across a 66 microhole array interface between the water and polyvinylchloride-2-nitrophenyloctylether gel layer is demonstrated. Since the transfer of hydrophilic anions including $Br^-$, $NO_3{^-}$, $I^-$, $SCN^-$ and $ClO_4{^-}$ across the liquid/gel interface usually sets the potential window within a negative potential region, a highly hydrophobic organic electrolyte, tetraoctylammonium tetrakis(pentafluorophenyl)borate, providing a wider potential window was incorporated into the gel phase. The transfer reaction of perchlorate anions across the microhole-water/gel interface was first studied using cyclic voltammetry and differential pulse voltammetry. The full voltammetric response of perchlorate anion transfer was then used as a reference for evaluating the half-wave transfer potentials, the formal transfer potentials and the formal Gibbs transfer energies of more hydrophilic anions such as $Br^-$, $NO_3{^-}$, $I^-$, and $SCN^-$. The current response associated with the perchlorate anion transfer across the micro-water/gel interface versus the perchlorate concentration was also demonstrated for sensing applications.

Psychological profiles of irritable bowel syndrome patients with different phenotypes

( Michel Bouchoucha ),( Ghislain Devroede ),( Noëlle Girault-lidvan ),( Maria Hejnar ),( Florence Mary ),( Robert Benamouzig ) 대한장연구학회 2020 Intestinal Research Vol.18 No.4

Background/Aims: Abnormal psychological profiles are frequently found in patients with functional gastrointestinal disorders (FGIDs). The present study aimed to evaluate the psychological profiles of FGID patients with irritable bowel syndrome (IBS), and IBS phenotypes. Methods: In 608 FGID patients, including 235 with IBS, have filled a Rome III questionnaire and the French version of the Minnesota Multiphasic Personality Inventory 2. Data analysis was performed using univariate analysis and multivariate logistic regression. Results: This study shows that IBS patients have abnormal psychological profiles with more significant symptom exaggeration and decreased test defensiveness than non-IBS patients. They have a significantly higher score for all clinical scales. Logistic regression analysis showed in IBS patients a decrease of body mass index (P=0.002), and test defensiveness score K (P=0.001) and an increase of Hypochondriasis (P<0.001) and Masculinity-Femininity scale (P=0.018). By comparison with non-IBS patients, IBS-constipation, IBS-diarrhea, and mixed IBS patients have increased Hypochondriasis value and Depression score, mixed IBS patients have higher Psychasthenia score and higher Hypomania score. No item was significantly different in the IBS-unspecified group. Conclusions: This study shows that IBS patients have different psychological profiles than other FGID patients and that psychological characteristics are associated with IBS phenotypes except for patients with unsubtyped IBS. (Intest Res 2020;18:459-468)

Portable Amperometric Perchlorate Selective Sensors with Microhole Array-water/organic Gel Interfaces

Lee, Sang Hyuk,Kim, Hyungi,Girault, Hubert H.,Lee, Hye Jin Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.9

A novel stick-shaped portable sensing device featuring a microhole array interface between the polyvinylchloride-2-nitrophenyloctylether (PVC-NPOE) gel and water phase was developed for in-situ sensing of perchlorate ions in real water samples. Perchlorate sensitive sensing responses were obtained based on measuring the current changes with respect to the assisted transfer reaction of perchlorate ions by a perchlorate selective ligand namely, bis(dibenzoylmethanato)Ni(II) (Ni(DBM)2) across the polarized microhole array interface. Cyclic voltammetry was used to characterize the assisted transfer reaction of perchlorate ions by the $Ni(DBM)_2$ ligand when using the portable sensing device. The current response for the transfer of perchlorate anions by $Ni(DBM)_2$ across the micro-water/gel interface linearly increased as a function of the perchlorate ion concentration. The technique of differential pulse stripping voltammetry was also utilized to improve the sensitivity of the perchlorate anion detection down to 10 ppb. This was acquired by preconcentrating perchlorate anions in the gel layer by means of holding the ion transfer potential at 0 mV (vs. Ag/AgCl) for 30 s followed by stripping the complexed perchlorate ion with the ligand. The effect of various potential interfering anions on the perchlorate sensor was also investigated and showed an excellent selectivity over $Br^-$, $NO_2{^-}$, $NO_3{^-}$, $CO{_3}^{2^-}$, $CH_3COO^-$ and $SO{_4}^{2^-}$ ions. As a final demonstration, some regional water samples from the Sincheon river in Daegu city were analyzed and the data was verified with that of ion chromatography (IC) analysis from one of the Korean-certified water quality evaluation centers.

Portable Amperometric Perchlorate Selective Sensors with Microhole Array-water/organic Gel Interfaces

Sang Hyuk Lee,Hyungi Kim,Hubert H. Girault,이혜진 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.9

A novel stick-shaped portable sensing device featuring a microhole array interface between the polyvinylchloride- 2-nitrophenyloctylether (PVC-NPOE) gel and water phase was developed for in-situ sensing of perchlorate ions in real water samples. Perchlorate sensitive sensing responses were obtained based on measuring the current changes with respect to the assisted transfer reaction of perchlorate ions by a perchlorate selective ligand namely, bis(dibenzoylmethanato)Ni(II) (Ni(DBM)2) across the polarized microhole array interface. Cyclic voltammetry was used to characterize the assisted transfer reaction of perchlorate ions by the Ni(DBM)2 ligand when using the portable sensing device. The current response for the transfer of perchlorate anions by Ni(DBM)2 across the micro-water/gel interface linearly increased as a function of the perchlorate ion concentration. The technique of differential pulse stripping voltammetry was also utilized to improve the sensitivity of the perchlorate anion detection down to 10 ppb. This was acquired by preconcentrating perchlorate anions in the gel layer by means of holding the ion transfer potential at 0 mV (vs. Ag/AgCl) for 30 s followed by stripping the complexed perchlorate ion with the ligand. The effect of various potential interfering anions on the perchlorate sensor was also investigated and showed an excellent selectivity over Br−, NO2 −, NO3 −, CO3 2−, CH3COO− and SO4 2− ions. As a final demonstration, some regional water samples from the Sincheon river in Daegu city were analyzed and the data was verified with that of ion chromatography (IC) analysis from one of the Korean-certified water quality evaluation centers.

Voltammetric Studies of Anion Transfer Reactions Across a Microhole Array-Water/PVC-NPOE Gel Interface

Md. Mokarrom Hossain,Hubert H. Girault,이혜진 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.5

Voltammetric characterization of hydrophilic anion transfer processes across a 66 microhole array interface between the water and polyvinylchloride-2-nitrophenyloctylether gel layer is demonstrated. Since the transfer of hydrophilic anions including Br−, NO3 −, I−, SCN− and ClO4 − across the liquid/gel interface usually sets the potential window within a negative potential region, a highly hydrophobic organic electrolyte, tetraoctylammonium tetrakis(pentafluorophenyl)borate, providing a wider potential window was incorporated into the gel phase. The transfer reaction of perchlorate anions across the microhole-water/gel interface was first studied using cyclic voltammetry and differential pulse voltammetry. The full voltammetric response of perchlorate anion transfer was then used as a reference for evaluating the half-wave transfer potentials, the formal transfer potentials and the formal Gibbs transfer energies of more hydrophilic anions such as Br−, NO3 −, I− and SCN−. The current response associated with the perchlorate anion transfer across the micro-water/gel interface versus the perchlorate concentration was also demonstrated for sensing applications.

Influence of Plastic Anisotropy and Strain path on strain-induced Phase Transformation of Cobalt

Pierre-Antoine Dubos,Jamal Fajoui,Baptiste Girault,David Gloaguen 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1

The objective of this paper is to contribute to a better understanding of the deformation mechanisms of a rolled polycrystalline cobalt sheet. In order to achieve this goal, a particular attention is given to the strain-induced phase transformation and the forming parameters on which it may depend such as the plastic anisotropy or the loading path. In situ phase quantification by X-ray diffraction during tensile tests, on samples cut out from a cold rolled sheet material in three different directions (at 0°, 45° and 90° from the rolling direction), has enabled to study the influence of plastic anisotropy on the strain-induced phase transformation of metastable retained Face Centered Cubic phase to Hexagonal Close Packed phase. Results show that the martensitic phase transformation can be activated by basal slip in the first stage of plasticity but it also indicates that the latter is delayed when sample is strained in tension for an angle of 45° to the rolling direction. Post mortem analyses on a stamped sample by the Nakazima test have revealed that the phase transformation continues for higher strain levels. A particular interest is paid to the coupling between strain-hardening mechanisms and phase transformation and is discussed given the plastic anisotropy of cobalt aggregate.