scholarly journals Acidic and Electrosurface Properties of Binary TiO2–SiO2 Xerogels Using EPR of pH-Sensitive Nitroxides

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 119
Author(s):  
Denis O. Antonov ◽  
Daria P. Tambasova ◽  
Andrey B. Shishmakov ◽  
Igor A. Kirilyuk ◽  
Elena G. Kovaleva
Keyword(s):  
Organic Synthesis ◽  
Electrostatic Potential ◽  
Electrical Potential ◽  
Ph Sensitive ◽  
Bulk Solution ◽  
Tio2 Content ◽  
Acid Base ◽  
Negative Surface ◽  
Further Development ◽  
Surface Electrostatic Potential

The binary xerogels TiO2–SiO2 are widely used as catalysts and their carriers in organic synthesis. Characterization and adjustment of the electrostatic properties of the surface and the local acidity inside the pores, are necessary for the further development of TiO2–SiO2 xerogels applications. This research investigates acid–base equilibria in the pores, and the surface electrostatic potential (SEP) of binary TiO2–SiO2 xerogels, by the EPR of stable pH-sensitive nitroxide radicals. These radicals are small enough to penetrate directly into the pores, and to be adsorbed onto the surface of the material under study. This makes it possible to obtain valuable information on the acidic and electrosurface properties of the studied system. The highest negative surface electrical charge associated with surface electrical potential (SEP) was equal to –196 ± 6 mV. It was induced by the surface of the sample with a 7% TiO2 content. Тhe local acidity inside the pores of this sample was found to be higher, by approximately 1.49 pH units, as compared to that in the external bulk solution.

Measurement System of Surface Electrostatic Potential on Insulation Board in Vacuum and its Application

2012 ◽  
Vol 132 (1) ◽  
pp. 95-100
Author(s):  
Hiroshi Morita ◽  
Ayumu Hatanaka ◽  
Toshiyuki Yokosuka ◽  
Yoshitaka Seki ◽  
Yoshiaki Tsumuraya ◽  
...  
Keyword(s):  
Electrostatic Potential ◽  
Measurement System ◽  
Surface Electrostatic Potential

Regulation of intracellular pH in proximal tubules of avian long-looped mammalian-type nephrons

1998 ◽  
Vol 274 (6) ◽  
pp. R1526-R1535 ◽  
Author(s):  
Olga H. Brokl ◽  
Christina L. Martinez ◽  
Apichai Shuprisha ◽  
Diane E. Abbott ◽  
William H. Dantzler
Keyword(s):  
Intracellular Ph ◽  
Ph Sensitive ◽  
Fluorescent Dye ◽  
Proximal Tubules ◽  
Acid Base ◽  
Rate Of Recovery

In nonperfused proximal tubules isolated from chicken long-looped mammalian-type nephrons, intracellular pH (pHi), measured with the pH-sensitive fluorescent dye 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, was ∼7.3 under control conditions (HEPES-buffered medium with pH 7.4 at 37°C) and was reduced to ∼7.0 in response to NH4Cl pulse. The rate of recovery of pHi from this level to the resting level was 1) significantly reduced by the removal of Na+ from the bath, 2) significantly increased by the removal of Cl− from the bath, 3) unchanged by the removal of both Na+ and Cl− from the bath, 4) significantly reduced by the addition of either ethylisopropylamiloride or DIDS to the bath, 5) significantly increased by a high bath K+ concentration, and 6) unchanged by the addition of Ba2+ to the bath. These data suggest that both Na+-coupled and Cl−-coupled basolateral acid-base fluxes are involved in determining the rate of recovery of pHi after acidification. The most likely ones to be important in regulating pHi are a Na+/H+exchanger and a Na+-coupled Cl−/[Formula: see text]exchanger. In birds, long-looped mammalian-type nephrons resemble short-looped transitional nephrons but differ markedly from superficial loopless reptilian-type nephrons.

Regulation of intracellular pH in avian renal proximal tubules

1997 ◽  
Vol 272 (1) ◽  
pp. R341-R349 ◽  
Author(s):  
Y. K. Kim ◽  
O. H. Brokl ◽  
W. H. Dantzler
Keyword(s):  
Intracellular Ph ◽  
Acid Level ◽  
Basolateral Membrane ◽  
Ph Sensitive ◽  
Fluorescent Dye ◽  
Proximal Tubules ◽  
Acid Base ◽  
Renal Proximal Tubules ◽  
Rate Of Recovery ◽  
Ethanesulfonic Acid

In proximal tubules isolated from chicken transitional nephrons, intracellular pH (pHi), measured with the pH-sensitive fluorescent dye 2'.7'-bis(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF), was approximately 7.3-7.4 under control conditions [N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered medium with pH 7.4 at 39 degrees C] and was reduced to approximately 6.8 in response to NH4Cl pulse. The rate of recovery of pHi (dpHi/dt) from this acid level to the resting level and the resting pHi were 1) significantly reduced by the removal of Na+ from the bath, 2) significantly increased by the removal of Cl from the bath, and 3) unchanged by the removal of both Na+ and Cl from the bath. The addition of either amiloride or 4,4'-diisothiocyanostilbene-2,2'-disulfonate to the bath reduced dpHi/dt to about the same extent as the removal of Na+. These data suggest that both Na(+)-coupled and Cl-coupled acid-base fluxes at the basolateral membrane are involved in determining the resting pHi and the rate of recovery of pHi after acidification. The most likely possibilities appear to be a basolateral Na+/Hi exchanger, a basolateral Na(+)-coupled Cl/HCO3 exchanger, a basolateral Na(+)-HCO3(-)CO(3)2 cotransporter, and a basolateral Na(+)-independent Cl-/HCO3 exchanger.

Methyl-2-methyl-2-(4-methyl-phenyl)sulfonamido propanoate: structural study, supramolecular architecture and analysis of molecular surface electrostatic potential

2016 ◽  
Vol 231 (9) ◽  
Author(s):  
Paramita Chatterjee ◽  
Tanusri Dey ◽  
Uday Das ◽  
Vommina V. Sureshbabu ◽  
Alok K. Mukherjee
Keyword(s):  
Structural Study ◽  
Electrostatic Potential ◽  
Molecular Surface ◽  
Supramolecular Architecture ◽  
Surface Electrostatic Potential ◽  
Methyl Phenyl

AbstractAn arylsulfonamide compound, methyl-2-methyl-2-(4-methylphenyl)sulfonamido propanoate, (

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