Results 1 - 10 of 38579
Results 1 - 10 of 38579. Search took: 0.055 seconds
|Sort by: date | relevance|
[en] The hemicyanine-based fluorescent probe L3 was demonstrated as a suitable membrane physiological pH probe. L3 easily interacted with the lipid components and anchored in inner membrane and gave a red fluorescence signal (~ 650 nm) in neutral or acidic pH, while the emission switching off when intramembrane pH varied to basic. Moreover, the absorption color of L3 changed from purple red to colorless with increasing pH. Thus L3 served as the pH-dependent modulator, a dual optical biomembranes pH sensing probe, showing good linear relationship in physiological pH range 7.0–8.5 or 7.5–9.0. The liposomes prepared under random pH and suspensions of gastric cancer cells (HGC-27) samples were used for verification of proposed intracellular pH sensing method, and satisfied results were obtained.
[en] The aim of this study was to evaluate the influence of high pH plum released from the disposal area on the Cs-137 sorption on the loess layer. Bach sorption tests showed that cesium sorption is decreased at high pH of contacting solution. Depending on the initial cesium concentration in the contacting solution, the cesium distribution coefficient (Kd) decreased with a factor of almost 4, while at lower cesium concentration the decrease factor is lower (~2). At very low cesium concentration, the Kd at high pH seems to not be affected (a slightly higher Kd value was obtained but this increase could be due to the inherent experimental errors). But even in this high pH conditions the percentage of cesium sorbed on loess samples is higher than 95.5%. (authors)
[en] Anthropogenic or natural exposure of sulfide-containing minerals to air and water causes the sulfide to oxidize to sulfate (SO42-) via abiotic or biotic reactions that release high amount of acidity.
[en] Highlights: • NiAl-NO3-LDH and NiAl-CO3-LDH were purposefully fabricated by HMT hydrolysis. • Proper acid-base activity sites were tunably established on NiAl-LDHs. • Acidic sites stemming from low coordination Ni2+ in NiAl-NO3-LDH were confirmed. • The inherent law of pH orienting the establishment of activity sites was revealed.
[en] The potentiodynamic behaviour of indium is studied in 0.5 M NaOH solutions. The effects of aging are reported and several mechanisms for the oxidation of indium, involving electrochemical reactions, are also proposed. (C.L.B.)
[pt]Estuda-se o comportamento potenciodinamico do indio em solucoes 0,5 M de NaOH. Relata-se os efeitos de envelhecimento e propoe-se mecanismos para as reacoes eletroquimicas responsaveis pela oxidacao do indio. (C.L.B.)
[en] The hydrothermal stability of smectite at temperatures less than 275 degrees C was investigated experimentally over a range of pH values. In the near-neutral pH region, the smectite to illite conversion predominated; in the mildly acid region, there was extensive formation of aluminum hydroxy interlayers in the clay; and in the alkaline region, framework silicates (feldspar and zeolites) were produced. The geological evidence for these reactions is also reviewed
[en] The possible changes of pH following anodic oxidation of niobium and aluminium volume-porous anodes are experimentally determined and theoretically calculated. The increase in acidity affects the structure and properties of the formed oxide film. The process of electrochemical formation of anode oxide films in porous bodies from niobium and aluminium is limitted by the diffusion processes. The usage of variable asymmetric current for Nb and Al oxidation acelerates diffusion processes, which constitutes to obtain anode oxide films with high dielectric properties
[en] The electrochemical reduction of TcO4- in non-complexing media, in the pH range 8 to 14 was studied with the techniques of sampled dc, normal pulse and reverse pulse polarography. The experimental conditions under which TcO42- is observed were established, and a mechanism is reported for its further reduction to Tc(V) in the pH range 9 to 12. The mechanism for reduction to Tc(V) is supported by the good agreement of the limiting currents, half-wave potentials and log plot slopes with the predictions of a digitally simulated ECE mechanism. The TcO4-/TcO42- reduction is reversible on a time scale of 3 msec and is pH independent. Its E0 is estimated to be -0.88 V vs. SCE. The disproportionation of Tc(VI) is not an important part of the mechanism of the two-electron reduction of TcO4- in the pH range 10 to 13, at ionic strength below 0.1 M and TcO4- concentrations below 5 x 10-4 M. Disproportionation of Tc(V) above pH 12 which is accelerated by hydroxyl ions leads to its further reduction to Tc(IV). A mechanism is proposed that accounts for the three electron reduction of TcO4- in strongly alkaline media. The electroreduction of TcO4- in the presence of ammonia and citrate is kinetically controlled at about pH 10. Ammonia and citrate apparently complex Tc(V) and lead to its further reduction to Tc(IV)