Silver reaction

The surface of the silver reaction channels was enhanced by means of the oxidation and outgassing reduction (OAOR) process, which relies on oxidation at 250 °C using pure oxygen and subsequent reduction. An increase in surface area by a factor of 2-3 was reached as indicated by chemisorption data. 

Notice that when the silver reaction is multiplied by 2 its E° value stays the same. The potential of a half-cell does not depend on the coefficients of the equation because the potential of the cell is independent of the quantities of reactants. Adding the two half reactions gives the overall reaction and the cell voltage ... 

One further observation should be made. There are occasional tiny black irregular specks (and one larger one) that are only found in scorch areas. These specks give a positive silver reaction and are undoubtedly due to the molten silver splatter at the time of the 1532 fire (J2). No lead was detectable, but a possible positive copper contaminant was seen in the large silver particle. 

Most recently, silver salts of complex anions have been shown to function in a similar way, simultaneously forming a black precipitate of metallic silver [reaction (11)], opening up the way for the use of a wide range of metal ion oxidants. 

Thus, instead of a limiting diffusion current density plateau, a curve inflection point or a short inclined plateau can be expected on the polarization curve in Ohmic-controlled electrodeposition of metals, as observed in the case of silver electrodeposition from nitrate solutions. The exchange current density of the silver reaction in nitrate electrolytes is sufficiently large to permit Ohmic-controlled deposition as well as dendritic growth at low overpotentials.27 After a linear increase of the deposition current density with increasing overpotential, an exponential increase after the inflection point appears, meaning the elimination of mass-transfer limitations due to the initiation of dendritic growth. 

Chromogenic in situ hybridization (CISH) is a recent methodology wherein the HER2/neu gene copies are detected by a silver reaction and visualized by light microscopy. A study that evaluated CISH on ThinPrep-processed hne-needle aspirate specimens found a good concordance between CISH performed on LBC specimens as compared to paraffin-embedded tissue specimens. 

Haug, F.-M. ., Blackstad, T. W., Hjorth-Simonsen, A. and Zimmer, J. (1971) Timm s sulfide silver reaction for zinc during experimental anterograde degeneration of hippocampal mossy fibres. J. comp. Neurol., 142, 23—32. 

Some dry AgF is charged into a silver reaction flask provided with a manometer and an inlet tube that can be closed off. The AgF can also be produced by the action of F g on the inner walls of the flask itself. After evacuation, pure, carefully dried Dg (see above, Dg) is admitted into the flask. The latter is then closed and heated to 110°C until the pressure ceases to change. The DF formed is frozen out of the reaction mixture by cooling with liquid nitrogen, and excess Dg is drawn off by suction after opening the flask. The.product is purified by high-vacuum distillation in which all connections and receivers must be of Ag or Cu. 

A number of metals are capable of giving a reaction similar to the one seen between manganese(n) and silver, but this is of no relevance since they need to be volatile to be brought from the sample solution to the silver manganese paper. But any substance that is sufficiently alkaline to enable the manganese silver reaction and volatile enough to evaporate from the sample solution imder the conditions set could give a positive reaction in the test. ... 

Note Use distilled, deionized, filtered water throughout and rinse well before the silver reaction because any residual salt present will result in high background. Only the chromosomal NORs should stain in mitotic cells and only nucleoli in interphase cells. If the nucleoplasm is stained, reduce the staining time to achieve the proper specificity. 

The exchange current density of the silver reaction in nitrate electrolytes is sufficiently large to permit ohmic-controlled deposition, as well as dendritic growth at low overpotentials [30]. 

Ammonia. Test with the manganese-silver reaction, see page 334. 

These problems have been studied in detail in the writer s laboratory by a number of workers and suitable modifications made In the procedure to ensure the specificity of the silver reaction for the histochemical localization of AA in a variety of plant and animal tissues (Dave et al , 1968 Madhavan Unni and Shah, 1968 Dave et al., 1969 Chinoy,... 

In the hlstochemlcal methods outlined by various workers, no proper mention is made of the controls. Besides, the above mentioned reactions establishing the specificity of the silver reaction for AA, Chinoy, N.J. (1969 a) and Chinoy, N.J. and Sanjeevan (1978) have Indicated a number of precautions to be observed In using the method which are as follows ... 

D. M. Silver, Reaction paths for bimolecular hydrogen exchange, Chem. Phys. Lett. 14 105 (1972). 

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