Proton Conductor
Mostrando 1-12 de 20 artigos, teses e dissertações.
-
1. Properties and applications of perovskite proton conductors
A brief overview is given of the main types and principles of solid-state proton conductors with perovskite structure. Their properties are summarized in terms of the defect chemistry, proton transport and chemical stability. A good understanding of these subjects allows the manufacturing of compounds with the desired electrical properties, for application i
Materials Research. Publicado em: 2010-09
-
2. Nuclear magnetic resonance study of proton conductor HPb2Nb3O10. nH2O. / Estudo por Ressonância Magnética Nuclear do Condutor Protônico HPb2Nb3O10. nH2O.
The protonic conductor HPb2Nb3O10. nH2O , was studied by pulsed Nuclear Magnetic Resonance (NMR) of ANTPOT.1H. The temperature dependence of the spin-lattice relaxation rate (1/T IND.1) and line width, reflect the mobility of the protonic species present in this material. The onset of ionic and molecular motions produces a strong narrowing of the line at tem
Publicado em: 1998
-
3. Respiration-driven Na+ pump and Na+ circulation in Vibrio parahaemolyticus.
Sodium circulation in Vibrio parahaemolyticus was investigated. We observed respiration-driven Na+ extrusion from cells by using a Na+ electrode. The Na+ extrusion was insensitive to a proton conductor, carbonyl cyanide m-chlorophenylhydrazone, and sensitive to a respiratory inhibitor, CN-. These results support the idea of the existence of a respiratory Na+
-
4. Sucrose uptake is driven by the Na+ electrochemical potential in the marine bacterium Vibrio alginolyticus.
Na+ was found to be essential for the accumulation of sucrose by Vibrio alginolyticus. Sucrose uptake was completely inhibited by the addition of proton conductor at neutral pH, but not at alkaline pH, where the primary electrogenic Na+ pump generates the Na+ electrochemical gradient. We therefore conclude that sucrose transport is driven by the electrochemi
-
5. Hydrogen-mediated mannose uptake in Azotobacter vinelandii.
Azotobacter vinelandii can grow mixotrophically with H2 plus mannose under N2-fixing conditions (T. Y. Wong and R. J. Maier, J. Bacteriol. 163:528-533, 1985). Mixotrophically grown cultures incubated in H2 transported mannose with a Vmax fourfold greater than that observed for cultures incubated in argon, but H2 did not change the apparent Km for mannose. Re
-
6. Protonation and Light Synergistically Convert Plasmalemma Sugar Carrier System in Mesophyll Protoplasts to its Fully Activated Form 1
The course of sugar fluxes into and out of protoplasts isolated from the mesophyll of Pisum sativum L. has been followed over brief time intervals (minutes). Light strongly stimulated net sugar influx at pH 8 as well as at pH 5.5. The proton conductor carbonyl cyanide m-chlorophenylhydrazone (CCCP) inhibited initial influx in the light, both at pH 8.0 and at
-
7. Proton translocation coupled to trimethylamine N-oxide reduction in anaerobically grown Escherichia coli.
Proton translocation coupled to trimethylamine N-oxide reduction was studied in Escherichia coli grown anaerobically in the presence of trimethylamine N-oxide. Rapid acidification of the medium was observed when trimethylamine N-oxide was added to anaerobic cell suspensions of E. coli K-10. Acidification was sensitive to the proton conductor 3,5-di-tert-buty
-
8. A Protonmotive Force Drives ATP Synthesis in Bacteria
When cells of Streptococcus lactis or Escherichia coli were suspended in a potassium-free medium, a membrane potential (negative inside) could be artificially generated by the addition of the potassium ionophore, valinomycin. In response to this inward directed protonmotive force, ATP synthesis catalyzed by the membrane-bound ATPase (EC 3.6.1.3) was observed
-
9. Protonmotive force as the source of energy for adenosine 5'-triphosphate synthesis in Escherichia coli.
Net synthesis of adenosine 5'-triphosphate (ATP) in energy-depleted cells of Escherichia coli was observed when an inwardly directed protonmotive force was artificially imposed. In wild-type cells, ATP synthesis occurred whether the protonmotive force was dominated by the membrane potential (negative inside) or the pH gradient (alkaline inside). Formation of
-
10. Growth of a marine Vibrio alginolyticus and moderately halophilic V. costicola becomes uncoupler resistant when the respiration-dependent Na+ pump functions.
The growth of Vibrio alginolyticus and V. costicola, which possess respiration-dependent Na+ pumps, was highly resistant to the proton conductor carbonyl cyanide-m-chlorophenyl hydrazone (CCCP), in alkaline growth media, even though the membrane was rendered permeable to H+. The pH dependence of CCCP-resistant growth was similar to that of the Na+ pump. In c
-
11. Active efflux of bile salts by Escherichia coli.
Enteric bacteria such as Escherichia coli must tolerate high levels of bile salts, powerful detergents that disrupt biological membranes. The outer membrane barrier of gram-negative bacteria plays an important role in this resistance, but ultimately it can only retard the influx of bile salts. We therefore examined whether E. coli possessed an energy-depende
-
12. Coupling of Energy to Folate Transport in Lactobacillus casei
Lactobacillus casei cells can accumulate folate to an intracellular concentration in excess of 500 μM and to concentration gradients (relative to the extracellular compartment) of several thousand-fold. Maximum rates of folate transport are achieved rapidly (t1/2 < 1 min) after the addition of glucose to energy-depleted cells and occur at intracellular aden