Tungsten cells preparation

Hippocampal slices (400-500 frm) were quickly prepared from male Wistar rats (8- to 9-weeks-old) and maintained in a chamber at 35 °C, where they were continuously perfused with artificial cerebrospinal fluid as described in our previous paper [11]. A bipolar tungsten electrode was placed in the stratum radiatum to stimulate Schaffer collateral and commissural afferents. The evoked potential was extracellularly recorded from the pyramidal cell layer of the CA1 subfield with a glass capillary microelectrode. A single test stimulation (0.05 msec duration) was applied at intervals of 30 sec. Drugs were delivered by perfusion. To induce potentiation of the evoked potentials, tetanic stimulation was applied at the same intensity through the same stimulating electrode as used for the test stimulation. The magnitude of LTP was evaluated by the population spike amplitude 30 min after tetanic stimulation. 

Although sample preparation was conducted under great care to minimize the analytical error, the potential for contamination does exist. As a precaution, tungsten and cobalt were removed from consideration during the statistical analysis of data because samples were powdered using a tungsten carbide cell grinder in which W is a major component and Co is a minor component. 

Crystals of the various alkali tungsten bronzes were prepared by electrolysis from a melt of the appropriate alkali tungstate and W03. The electrolytic cell consisted of a glazed ceramic crucible, a Chromel wire cathode, and a graphite anode. Crystals were obtained under the following conditions temperatures of the melt, 750° to 900° C. current through the cell, 15 to 50 ma. time of electrolysis, 12 to 24 hours. 

EC-STM was carried out with a Nanoscope E microscope (Veeco Metrology, Santa Barbara, CA) equipped with a custom-built Kel-F electrochemical cell. The tunneling tips were prepared by electrochemically etching a tungsten wire, 0.25-mm in diameter, in 1 M KOH at 15 VAC. The attaimnent of atomically sharp STM tips may be confirmed with a microscope of at least 1000-fold magnification. The choice tips were then coated with transpa-... 

Tungsten disulfide WS2 [10.8] is used for electrode activation in fuel cells. If produced by hydrogen reduction of (NH4)2WS4, it exhibits a BET surface 70 times larger than that of commercially prepared WS2. It acts as catalyst for the reaction... 

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