Metal-containing ionic liquids (ILs) have been recognized as potential solvents, catalysts, catalyst precursors and reagents for many organic processes. In this work, several quantum-chemical parameters, including the surface electrostatic potential (Vs,max and Vs,min), the lowest surface average local ionization energy (I̅s,min), and the electrostatic potential at the position of an atom (EPnuc...

OBJECTIVE To study the effects of the somatostatin analog octreotide on gastric mucosal function and histology during short-term (3 months) preoperative treatment in patients with acromegaly. DESIGN Open design clinical study. METHODS 10 patients were studied before treatment with octreotide (pre-tx), on day 1 of 300 microg octreotide/day (d300), after 1 week on 300 (w300), 600 (w600) or 15...

The first acidity scale to be established in a pure solvent other than water was the result of the pioneering work of Conant, Wheland, and McEwen in ether or ben~ene .~ During the past 20 years an ion-pair acidity scale covering an "effective pKa rangefrom about 15 to 40 has been developed in cyclohexylamine (CHA),6 and similar studies in other low-dielectric-constant solvents including 1,2-dim...

BACKGROUND High consumption of nonalcoholic beverages is one of the causes of dental erosion. Annual consumption of beverages in Iran is 48 LPCY (Lit per capita per year) that is equal to 144 bottles per capita in year and is relatively a high rate. Taking this into consideration, the present study was planned to determine the pH and fluoride content of beverages consumed in Kerman, south east ...

Unlike the digestive systems of vertebrate animals, the lumen of the alimentary canal of Caenorhabditis elegans is unsegmented and weakly acidic (pH ~4.4), with ultradian fluctuations to pH > 6 every 45-50 s. To probe the dynamics of this acidity, we synthesized novel acid-activated fluorophores termed Kansas Reds. These dicationic derivatives of rhodamine B become concentrated in the lumen of ...

Vapor adsorption is an important process influencing the migration and the fate of many organic pollutants in the environment. In this study, vibrational sum frequency generation (SFG) spectroscopy was used to study the adsorption of two surface acidity probe molecules, 4-picoline (pKa = 5.94) and piperidine (pKa = 11.24), onto the amorphous SiO2 surface. The adsorption of 4-picoline onto the s...

The influence of framework substituents (Al3+, Ga3+, Fe3+ and B3+) and morphology (bulk vs. nanometer-sized sheets) of MFI zeolites on the acidity and catalytic performance in the methanol-to-hydrocarbons (MTH) reaction was investigated. The Brønsted acid density and strength decreased in the order Al(OH)Si>Ga(OH)Si>Fe(OH)Si≫B(OH)Si. Pyridine 15N NMR spectra confirmed the differences in the Brø...

Acidity functions were used to express the ability of a solvent/solution to donate/accept a proton to a solute. The present work accounts for the acidity determination of HCOOH, CH3COOH, and CH3CH2COOH in the alkylimidazolium-based protic ionic liquids (PILs), incorporated with carboxylate anion, water, and in a binary mixture of PIL and water using the Hammett acidity function, H0. A reversal ...

The intrinsic acidity of CH2[double bond, length as m-dash]CHXH2, HC[triple bond, length as m-dash]CXH2 (X = N, P, As, Sb) derivatives and of their complexes with BeH2 and BH3 has been investigated by means of high-level density functional theory and molecular orbital ab initio calculations, using as a reference the ethyl saturated analogues. The acidity of the free systems steadily increases d...