Search results for "blue"
showing 10 items of 487 documents
The role of inner counterions within PB films during electrochemical processes
1999
Abstract The shape of voltammograms of Prussian Blue films (ferric ferrocyanide, PB) deposited on ITO (indium–tin oxide) electrodes in aqueous KCl, CsCl and NH 4 Cl solutions has been studied. These results proved a double role of countercations during these electrochemical processes. Countercations can either be only retained within the zeolitic pores of the PB structure forming part of their inner solution, or can also form part of the crystalline structure of PB films by replacing some iron sites. The different electrochemical behaviour of PB films in the three studied solutions (KCl, CsCl and NH 4 Cl) is analysed from this point of view.
An Electronic Perspective On The Electrochemical Changeover In Prussian Blue-Like Materials
2009
Derivative voltabsometric scans together with previous electrogravimetric results allow to distinguish between the different electrochemical processes due to Fe-sites located into the Prussian Blue crystalline framework and other located next to ferrocyanide vacancies. The potassium, proton and hydrated proton counterions involved in these reactions are correlated to changes in near-UV/VIS/near-IR spectra. Potassium counter-ions show two different sites for insertion: one located into the crystalline framework and the other into ferrocyanide vacancies. From the monitoring of electroactive Fe-sites, it is possible to assume that the reduction of all Fe-sites located next to ferrocyanide vaca…
Electronic Perspective on the Electrochemistry of Prussian Blue Films
2009
The derivative of the voltabsommetric scans, together with previous nano-electrogravimetric and X-ray diffraction results, allow different electrochemical processes to be distinguished during the Prussian blue (PB) voltammetric scan. Potassium, proton, and hydrated proton counterions involved in PB electrochemistry are related here to the electrochemical reactions of specific Fe sites. Potassium counterions show two different sites for their insertion: one located in the crystalline framework and another in ferrocyanide vacancies. From the monitoring of electroactive Fe sites, the covalent-exchange model is suggested as one of the first approaches to explain the origin of the PB magnetic or…
Usefulness of F(dm/dQ) Function for Elucidating the Ions Role in PB Films
2007
The conversion process of "insoluble" prussian blue (PB) films into the "soluble" structure has been followed by the simultaneous measurement of current and mass changes during voltammetric experiments and focusing on the possibilities of the use of the instantaneous mass/electrical charge ratio at each potential. A similar procedure was used for the analysis of the mechanism of reduction of PB films to the Everitt's salt form and to follow the partial dissolution of iron species during the oxidation to the prussian yellow form. The possibility of covering PB films by Nafion membranes, which make difficult the transport of anions through it, allows us to discern the role of anions in the so…
Usefulness of the Instantaneous Mass-charge Ratio for Elucidating the Ions Role in the Stabilization and Dissolution Processes in Prussian Blue Films
2007
The conversion process of 'insoluble' Prussian Blue films into the 'soluble' structure has been followed by the simultaneous measurement of current and mass changes during voltammetric experiments and focusing on the possibilities of the use of the instantaneous mass/electrical charge ratio at each potential. A similar procedure was used for the analysis of the mechanism of reduction of Prussian Blue films to the Everitt's Salt form and to follow the partial dissolution of iron species during the oxidation to the Pussian Yellow form. The possibility of covering Prussian Blue films by Nafion membranes which make difficult the transport of anions through it allows to discern the role of anion…
Antimicrobial activity of methylene blue and toluidine blue O covalently bound to a modified silicone polymer surface
2009
Methylene Blue or Toluidine Blue O were covalently bound to an activated silicone polymer by means of an amide condensation reaction. UV-visible absorption spectra confirmed that the dye was surface bound. The new polymers with covalently attached dye display significant bactericidal activity against Escherichia coli and Staphylococcus epidermidis with a 99.999% reduction in viable bacteria after four minutes exposure to a low power laser.
Time-monitoring sensor based on oxygen diffusion in an indicator/polymer matrix
2013
Abstract A time-monitoring sensor based on the oxidation of leuco methylene blue (LMB) to methylene blue (MB) was developed. The sensor changes its color from yellow to green in the presence of oxygen and was integrated into a poly(vinyl alcohol) matrix. The diffusion of the oxygen in the polymer matrix as well as the oxygen uptake due to the oxidation reaction determines the time monitoring of the sensor. A physical model has been developed that accounts for both the diffusion as well as the oxidation reaction. For this purpose, the reaction kinetics was determined experimentally. Moreover, the diffusion coefficient of oxygen was determined and concentration profiles in the polymer matrix …
Taurine and the Lung
2003
Taurine (TAU) is the most abundant free amino acid in many tissues and in particular in proinflammatory cells like polymorphonuclear leukocytes and tissues exposed to elevated levels of oxidants1. Furthermore, orally administered TAU has been reported to reduce lung oxidant damage from exposure to ozone, nitrogen dioxide, paraquat, amiodarone and bleomycin in animal models2–5.
Cucurbit[n]uril-capped upconversion nanoparticles as highly emissive scaffolds for energy acceptors.
2015
Spontaneous adsorption of cucurbit[n]uril CB[n] (n = 6, 7, and 8) on the surface of naked upconversion nanoparticles (UCNPs), in particular, NaYF4:Er3+(2%),Yb3+(18%) gave rise to UCNP@CB[n] exclusion complexes. These complexes proved to be highly stable as well as highly emissive under near-infrared excitation. By using two tricyclic basic dyes (specifically, methylene blue and pyronin Y) as a proof of concept, we demonstrate that the UCNP@CB[n] (n = 6, 7) nanohybrids can form exclusion complexes with this type of dyes via the CB carbonyl free portal, i.e., UCNP@CB@dye hybrids, thus making it possible to locate a high concentration of the dyes close to the UCNP and, consequently, leading to…
Comparison of the Effects of Indole-3-Acetic Acid and Kinetin on the Photosynthetic Apparatus and on the Cell Metabolism
1984
External and internal factors can exert a regulatory influence on growth and differentiation within a reaction norm determined by the genetic material. As to the internal factors, the phytohormones intervene in the most development processes in a regulatory manner. In a number of publications it was pointed out that there is a far-reaching accordance between the effects caused by I.4A and the effects induced by red light and low light conditions (Zerbe, Wild, 1980 a; Holzapfel et al., 1982 a). Plants of Sinapis alba grown under low light conditions but additionally treated with kinetin show changes in their metabolism that are characteristic of plants grown at higher light intensities (Zerb…