Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Platinum catalysts are involved in a vast variety of redox reactions, and O 2 reduction is one of the most important of them. Therefore, considerable efforts are undertaken by electrochemists to understand the fundamental aspects of Pt catalysts and to improve the properties of applied catalytic systems in general. The fundamental relevance of Pt catalytic properties has become even more important because carbon-supported Pt catalysts have so far been the best choice for the oxygen reduction at the cathode of low-temperature polymer electrolyte membrane fuel cells ͑PEMFCs͒. 1The oxygen reduction reaction ͑ORR͒ on Pt surfaces has been widely studied in electrochemistry, but the details of the mechanism remain elusive. The overall ORR is a multistep process involving four electron transfers during which bonds are broken and formed. It is still not clear whether the process starts from the oxygen molecule dissociation on Pt electrodes, this being followed by electron and proton transfer, or whether the first reduction step happens before O-O bond cleavage. Damjanovic proposed that the first step is an electron transfer to the O 2 moleculeThis step is rate-determining and is either accompanied by or followed by a fast proton transfer. A theoretical study by Sidik et al. has proven the first electron transfer to be rate-determining on dual adsorption sites. Proton transfer is involved in this step, because the electron affinity of the reactant complex is increased significantly by t...

This study was designed to determine (1) which brain area paces the 8 rhythm in the medial entorhinal cortex (MEC) of rats and (2) the extent to which the behavioral effects of lesions in the medial septal area (MSA), which disrupt the cholinesterase-related pathway to the hippocampal formation, resemble the effects previously reported to result from fimbria-fornix lesions.MSA lesions abolished or decreased B rhythm in dorsal hippocampus (DHPC) and MEC; acetylcholinesterase (AChE) staining was depleted or diminished in all of the hippocampus and entorhinal cortex. Rats with MSA lesions were impaired on acquisition of a radial arm maze task.Unilateral fimbria lesions left 8 rhythm and AChE staining essentially unaltered in ipsilateral DHPC and MEC but depleted AChE in ipsilateral ventral hippocampus (VHPC) and ventral lateral entorhinal cortex (LEC). A lesion of the dorsal fornix at the level of the hippocampal flexure left ipsilateral DHPC 8 rhythm and AChE stain unaltered while causing a substantial reduction in 0 rhythm and depletion of AChE in ipsilateral MEC. AChE staining was complete in VHPC and LEC.These results suggest that MSA paces MEC 8 rhythm and that the presumed cholinergic projection which mediates this function travels in the dorsal fornix. The fimbria carries a presumed cholinergic projection to ventral LEC. Rats with MSA lesions can learn a radial arm maze task, unlike rats with fimbria-fornix lesions, but they learn significantly slower than normal rats.

We study the static and dynamic properties of bromine electrosorption onto single-crystal silver (100) electrodes by Monte Carlo simulation. At room temperature the system displays a second-order phase transition between a low-coverage disordered phase at more negative electrode potentials and a c(2 × 2) ordered phase with bromine coverage 1/2 at more positive potentials. We explore the phase diagram and demonstrate that the broad shoulder observed in room-temperature cyclic voltammograms is due to local fluctuations resembling ordered phases with coverage 1/4, which exist in the model at much lower temperatures. We construct a dynamic Monte Carlo algorithm using a thermally activated stochastic barrier-hopping model for the microscopic dynamics. We use this algorithm to study the phase ordering and disordering processes following sudden potential steps between the disordered phase and the c(2 × 2) phase, and to study the sweep-rate dependence in simulated cyclic-voltammetry experiments.

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We describe direct measurements of the dynamics of two colloidal spheres before hydrodynamic interactions have had time to fully develop. We find that the dynamics of the two spheres are coupled at times significantly shorter than tau(nu), the time required for vorticity to diffuse between the two spheres. From the distance dependence of the measured coupling, we infer that hydrodynamic interactions develop in a sonic time scale.

The isolation of five known cembranoid diterpenes, (1), (2), (3), (4) and ( 5 ) , is reported from the soft coral Nephthea brassica. These diterpenes co-occur with several new but related diterpenes: (13S)-cembra-1,3,7,11-tetraen-13-ol (6) and its corresponding 13-acetate (7), 15-acetoxycembra-3,7,11-triene (8), (10S)-10,15-diacetoxy-7,8-epoxycembra-3,11-diene (9) and its corresponding 10-monoacetoxy derivative (10). Two related cembranoid diterpenes, (14S)-acetoxycembra-1,3,7,11-tetraene (15) and (14S)-cembra-1,3,7,11-tetraen-14-01 (16), are reported from a soft coral of the genus Sarcophyton.

The isolation of two new sesquiterpenes (3) and (4), related to the known sesquiterpenes lemnalactone(1) and 2-deoxylemnacarnol (5), is reported from the soft coral Paralemnalia thyrsoides. Their structures were deduced from spectroscopic data, and confirmed by conversion into known sesquiterpenes. A semisystematic nomenclature, based on the name 'lemnalan' for the trimethylperhydronaphtho[b]furan (8) parent structure, is suggested.