Potential induced

Ocko B M, Wang X J and Wandlowski Th 1997 Bromide adsorption on Ag(OOI) A potential induced two-dimensional Ising order-disorder transition Phys. Rev. Lett. 79 1511-14... 

Surface SHG [4.307] produces frequency-doubled radiation from a single pulsed laser beam. Intensity, polarization dependence, and rotational anisotropy of the SHG provide information about the surface concentration and orientation of adsorbed molecules and on the symmetry of surface structures. SHG has been successfully used for analysis of adsorption kinetics and ordering effects at surfaces and interfaces, reconstruction of solid surfaces and other surface phase transitions, and potential-induced phenomena at electrode surfaces. For example, orientation measurements were used to probe the intermolecular structure at air-methanol, air-water, and alkane-water interfaces and within mono- and multilayer molecular films. Time-resolved investigations have revealed the orientational dynamics at liquid-liquid, liquid-solid, liquid-air, and air-solid interfaces [4.307]. 

As indicated above, when a positive direct current is impressed upon a piece of titanium immersed in an electrolyte, the consequent rise in potential induces the formation of a protective surface film, which is resistant to passage of any further appreciable quantity of current into the electrolyte. The upper potential limit that can be attained without breakdown of the surface film will depend upon the nature of the electrolyte. Thus, in strong sulphuric acid the metal/oxide system will sustain voltages of between 80 and 100 V before a spark-type dielectric rupture ensues, while in sodium chloride solutions or in sea water film rupture takes place when the voltage across the oxide film reaches a value of about 12 to 14 V. Above the critical voltage, anodic dissolution takes place at weak spots in the surface film and appreciable current passes into the electrolyte, presumably by an initial mechanism involving the formation of soluble titanium ions. 

The glucan synthase inhibitor caspofungin (intravenous formulation) is new on the market for the treatment of invasive aspergillosis in patients whose disease is refractory to, or who are intolerant of, other therapies. During the clinical trials fever, infused vein complications, nausea, vomiting and in combination with cyclosporin mild transient hepatic side effects were observed. Interaction with tacrolismius and with potential inducer or mixed inducer/inhibitors of drug clearance was also seen. 

Excitation-contraction coupling (EC coupling) is the mechanism underlying transformation of the electrical event (action potential) in the sarcolemma into the mechanical event (muscle contraction) which happens all over the muscle. In other words, it is the mechanism governing the way in which the action potential induces the increase in the cytoplasmic Ca2+ which enables the activation of myofibrils. 

There remains the estimated value of °(H+/H2)vs. UHV based on binding energies for image potential-induced surface states,49 which is,... 

Kolb and Franke have demonstrated how surface reconstruction phenomena can be studied in situ with the help of potential-induced surface states using electroreflectance (ER) spectroscopy.449,488,543,544 The optical properties of reconstructed and unreconstructed Au(100) have been found to be remarkably different. In recent model calculations it was shown that the accumulation of negative charges at a metal surface favors surface reconstruction because the increased sp-electron density at the surface gives rise to an increased compressive stress between surface atoms, forcing them into a densely packed structure.532... 

When an action potential arrives at the axon terminal, it induces the release of a chemical transmitter. Transmitter release is a Ca +-dependent process (see Chapter 4) and requires a charge of Ca +. This is provided through the action potential-induced... 

The abilities of this approach will then be illustrated with two examples (i) the potential-induced lifting of the Au(lOO) surface reconstruction and (ii) the electrochemical oxidation of Pt(l 11). 

Besides surface reconstructions induced by heat treatment, potential-induced reconstruction has recently become a topic of interest in electrochemistry. It has been observed that at potentials negative with respect to the potential of zero surface charge, [Kolb, 1996, 2002 Dakkouri, 1997], the reconstructions found under UHV conditions are also stable in contact with an electrolyte. Although aU low index faces of Au and Pt undergo potential-induced reconstruction, it has been particularly well characterized for Au(lOO) (Fig. 5.5). 

We have also discussed two applications of the extended ab initio atomistic thermodynamics approach. The first example is the potential-induced lifting of Au(lOO) surface reconstmction, where we have focused on the electronic effects arising from the potential-dependent surface excess charge. We have found that these are already sufficient to cause lifting of the Au(lOO) surface reconstruction, but contributions from specific electrolyte ion adsorption might also play a role. With the second example, the electro-oxidation of a platinum electrode, we have discussed a system where specific adsorption on the surface changes the surface structure and composition as the electrode potential is varied. 

Haftel Ml, Rosen M. 2003. Surface-embedded-atom model of the potential-induced lifting of the reconstruction of Au(lOO). Surf Sci 523 118-124. 

Jacob T. 2007a. Potential-induced lifting of the Au(100)-surface reconstruction studied with DFT. Electrochim Acta 52 2229-2235. 

Jacob T. 2007b. Theoretical investigations on the potential-induced formation of Pt-oxide surfaces. J Electroanal Chem 607 158-166. 

Ag/AgCl electrodes were inserted in the plant at different positions. Following insertion of the electrodes, the plants were allowed to rest until a stable potential difference was obtained between the measuring and reference electrodes. Insertion of electrodes in plants induces action potentials across the stem and slow fluctuations of the resting potential (Fig. 5). After approximately 1-2 h, the resting potential stabilizes and action potentials induced by wounding disappear (Fig. 6). 

The fastest velocity reported for transmission of action potentials in green plants was 0.2 m/s in Dionaea flytrap [11]. Action potentials induced in soybean by FCCP are 200 times... 

The speed of the propagation of action potentials in potato plants also depends on the external stimuli. The speed of action potential induced by pinching the terminal leaflet of a potato plant is equal to 7 2cm/s [6,7]. The speed of propagation of the action potential induced in the terminal leaflet by thermal shock is equal to 0.7 0.2cm/s [7]. 

The speed of propagation of the action potential does not depend on the location of a working electrode in the stem of the plant [Figs. 19(a)-(c)] or in the tuber [Figs. 19(d) and 20], or on the distance between the working and reference electrodes (Fig. 21). The speed of propagation of the action potential induced by the Colorado potato beetle can be determined from the slope of the dependence of the time interval between peaks on the distance between electrodes (Fig. 21) and is about 0.05 cm/s. 

FIG. 21 The time dependence between positive and negative peaks of action potential induced by Colorado potato beetles on the distance between electrodes. The plants were given water every other day and kept at 20° C. A few electrodes were immersed in potato seed and different parts of the plant stem 2 h before measurements of the potential difference. (From Ref. 7.)... 

Sunscreens and their degradation metabolites analyzed in this study are potential inducers of the oestrogen (ER) and aryl hydrocarbon receptors (AhR, also known as Dioxin Receptor). Ectopic activation of these pathways can cause severe damage to organisms and their ecosystem by altering reproduction, hormonal and/or circulatory systems [73-75] as well as they have been associated with carcinogenic and mutagenic effects [76-78]. 

Lanahan A et al. Selective alteration of long-term potentiation-induced transcriptional response in hippocampus of aged, memory-impaired rats. J Neurosci 1997 17 2875-2885. 

Potential-induced changes in absorption due to adsorption or electron transfer reactions. 

---