Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Silver Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,513 records · Page 84Linked to original sources
PubMed2001

Bis(mu-2-cyanopyridine-N:N')bis[(2-cyanopyridine-N)silver(I)] bis(tetrafluoroborate): an anion-linked molecular ladder.

In the title compound, [Ag(2)(C(6)H(4)N(2))(4)](BF(4))(2), the Ag(I) cations adopt distorted trigonal-planar coordination geometries. The Ag(I) centres are linked via two bridging 2-cyanopyridine ligands to give a centrosymmetric dinuclear complex in which the Ag(I) coordination environment is completed by monodentate non-bridging 2-cyanopyridine ligands. Bridging Ag...F(BF(2))F...Ag interactions link the dinuclear cations into molecular ladders.

Journal Article↗
PubMed2001

Potassium silver tin selenide, K(2)Ag(2)Sn(2)Se(6).

The title compound was synthesized by a reactive salt reaction at 773 K over a period of 5 d. It has a one-dimensional chain structure consisting of K(+) cations and one-dimensional [Ag(2)Sn(2)Se(6)](2-) anions. The chain is constructed by edge-sharing bitetrahedral [Sn(2)Se(6)] units connected in a 1:2 ratio via linear Ag(+) ions.

Journal Article↗
PubMed2002

Silver-promoted reactions of bicyclo[3.2.1]octadiene derivatives.

[reaction: see text] Highly substituted bicyclo[3.2.1]octadiene building blocks are easily prepared from tetrachloro- or tetrabromocyclopropene through reaction with cyclic dienes. These polyhalogenated derivatives can serve as precursors to a variety of functionalized bridged bicyclic compounds. Herein, we report on the generation and reaction of electrophilic species with silver ion.

Journal Article↗
PubMed1987

Cytochemical demonstration of mercury deposits in trout liver and kidney following methyl mercury intoxication: differentiation of two mercury pools by selenium.

The amount and the ultrastructural distribution of mercury was studied in seven different organs of rainbow trout (Salmo gairdneri) fingerlings following exposure to methyl mercury (MeHg)-contaminated fodder for periods of 2 and 7 weeks. The amounts of mercury retained by the whole fish and the selected organs were determined by measuring the uptake of 203Hg-labeled MeHg. Spleen, liver, and kidney had the highest concentrations after both experimental periods, while the largest relative increases were found in brain, muscle, and kidney. The subcellular distribution of mercury accumulations was demonstrated cytochemically in liver and kidney using the silver enhancement method by which accumulations of mercury-sulfides and/or mercury-selenides are made visible for light and electron microscopy. When sections prepared from the liver and kidney from fish, injected with selenium 2 hr prior to being killed, were compared with those of fish not treated with selenium, two distinct pools of mercury could be demonstrated, the HgS pool, and the HgSe pool. The HgS pool, supposed to represent inorganic mercury, was found exclusively within lysosomes. The increase of this pool from 2 to 7 weeks was most pronounced in the kidney. The HgSe pool, supposed to represent methyl mercury, was shown by the presence of silver deposits at new locations as well as by an increase in the amount of deposits within lysosomes. The new locations included (1) secretory-like vesicles and the bile canaliculi of the liver, suggesting a biliary excretion of this mercury pool; (2) microvilli and endosomes of kidney tubular cells, suggesting a glomerular filtration and subsequent reabsorption; and (3) mitochondria of proximal tubule cells.

Animals↗
PubMed1992

Silver staining of collagen type I after sodium dodecylsulphate polyacrylamide gel electrophoresis: effect of Maillard reaction.

Differences in the acidic silver staining, after sodium dodecylsulphate polyacrylamide gel electrophoresis, between the alpha 1 and alpha 2 collagen chains, as well as between rat-tail tendon and calf-skin collagen type I, were observed. The staining conditions at which the staining differences are both most expressed and reproducible were characterized. Age differences between staining of the alpha 1 CB6 fragment from young rats (2 and 12 months) and old rats (29 months) indicated that different susceptibilities of collagen species to the silver staining can be the result of different extents of some age-dependent post-translational modification, such as glycation. In vitro incubation of acid-soluble rat-tail tendon collagen with various sugars led to an increase in silver staining compared with samples incubated in the absence of sugar. This effect was inhibited by sodium cyanoborohydride, diethylenetriamine pentaacetic acid and aminoguanidine, i.e. compounds inhibiting the Maillard reaction at various stages. It can be concluded that the enhanced silver susceptibility of glycated collagen is related to advanced-phase Maillard reaction products attached to collagen.

Animals↗
PubMed2006

Dye-labeled silver nanoshell-bright particle.

Silica beads with average diameters of 40-600 nm were prepared, and Ru(bpy)3(2+) complexes were incorporated into the beads. These beads were coated by silver layer by layer to generate porous but continuous metal nanoshells. The thicknesses of these metal shells were 5-50 nm. The emission band from the dyes in the silica cores was more narrow and the intensity was enhanced with growth of silver shell thickness due to coupling of the emission light from Ru(bpy)3(2+) in the cores with the metal plasmon from the silver shells. The enhancement of emission intensity was also dependent on the size of the silica core, showing that the enhancement efficiency decreased with an increase in the size of the silica beads. Lifetime measurements support the coupling mechanism between the dye and metal shell. This study can be used to develop novel dye-labeled metal particles with bright and narrow emission bands.

Fluorescent Dyes↗
PubMed2000

The solid-state electrochemistry of metal octacyanomolybdates, octacyanotungstates, and hexacyanoferrates explained on the basis of dissolution and reprecipitation reactions, lattice structures, and crystallinities.

The electrochemical behavior of solid microparticles of metal (Ag+, Cd2+, Co2+, Cr2+, Cu2+, Fe2+, Mn2+, Ni2+, Pb2+, and Zn2+) octacyanomolybdates, octacyanotungstates, and hexacyanoferrates has been studied by voltammetry, electrochemical quartz crystal microbalance, and microscopic diffuse reflectance spectroelectrochemical measurements. The solid microparticles have been immobilized on the surface of graphite electrodes prior to the electrochemical measurements. A comparative study of the cyclic oxidation and reduction of these compounds in the presence of potassium ions revealed that any interpretation of the electrochemistry requires the solubility equilibria of the reduced compounds to be taken into account, such as in the case of the silver salts [Ag3K[X]] and [Ag4[X]] (with X = FeII(CN)6(4-), MIV(CN)8(4-) (M = Mo, W)). Because [Ag4[X]] has a lower solubility than [Ag3K[X]], the electrochemistry is accompanied by a conversion of solid [Ag3K[X]] into solid [Ag4[X]]. Two distinct voltammetric signal systems are generated by these two compounds according to [Ag3K[X]] reversible [Ag3[X]] + K(+) + e- and [Ag4[X]] reversible [Ag3[X]] + Ag(+) + e-. When silver ions are present in the solution adjacent to the microparticles, the silver octacyanometalates and silver hexacyanoferrate show a chemically reversible and very stable voltammetric behavior. Despite the fact that the electrochemistry is based upon a single-electron/single-ion transfer reaction ([Ag4[X]] reversible [Ag3[X]] + Ag(+) + e-), more than one electrochemical signal is observed because of the simultaneous presence of amorphous and crystalline particles. This study shows that the interplay of solubility equilibria and electrochemical equilibria is generally observed for the other metal octacyanomolybdates, octacyanotungstates, and hexacyanoferrates as well.

Journal Article↗
PubMed1989

Silver staining of nucleolar organizer regions in malignant melanoma and melanotic nevi.

The recently described method of staining nucleolar organizer regions (NOR) with colloidal silver nitrate was applied to the paraffin sections of five junctional nevi, 13 compound nevi, seven Spitz nevi, nine cellular blue nevi, 11 dysplastic nevi, seven malignant lentigines, 12 superficial spreading melanomas, and 14 secondary melanomas. There was a significant difference between the pooled silver-NOR (AgNOR) numbers of the 45 benign lesions (mean, 1.22; SD, 0.51) and the 33 melanomas (mean, 9.18; SD, 4.05) by t test analysis (P less than .01). The difference was striking enough to be recognized on casual microscopic examination, suggesting that AgNOR staining may be a useful technique to help separate melanocytic nevi from malignant melanomas.

Colloids↗
PubMed1996

Regiochemical Control and Suppression of Double Bond Isomerization in the Heck Arylation of 1-(Methoxycarbonyl)-2,5-dihydropyrrole.

Arylation of 1-(methoxycarbonyl)-2,5-dihydropyrrole under standard Heck reaction conditions produces a mixture of compounds. The olefin undergoes two types of palladium-catalyzed reactions: (a) arylation to provide C-3 arylated derivatives and (b) competing double bond isomerization. Addition of silver carbonate and thallium acetate fully suppressed the isomerization, and good yields of C-3 substituted compounds were achieved after arylation with aryl halides. With regard to aryl triflates as arylating agents, addition of lithium chloride was necessary to promote the Heck reaction. This additive excluded the use of silver and thallium salts, but high regioselectivity and good yields could be obtained by employing tri-2-furylphosphine as ligand. Arylation was rendered both regioselective and enantioselective (58% ee) with 1-naphthyl triflate as substrate utilizing a (R)-BINAP/thallium acetate combination. The C-3 arylated enamides were converted further into the corresponding 3-arylpyrrolidines.

Journal Article↗
PubMed2005

An in situ silver cationization method for hydrocarbon mass spectrometry.

We have developed a novel cationization method for the analysis of long-chain hydrocarbons via UV laser desorption mass spectrometry. In this technique we electrospray a thin coating of AgNO3 over a sample and perform UV laser desorption to produce Ag+ cationization of sample molecules. Use of this technique in our microscope/TOF-MS allows us to determine the spatial distribution of the species we detect in the sample. We demonstrate 8-mu spatial resolution, and submicron resolution is possible in principle. In mixed samples containing aromatic and aliphatic compounds, the aromatic compounds ionize directly and do not form adducts, and thus give single peaks as opposed to doublets from silver cations. This enables distinction between aromatic and aliphatic compounds that are in the same sample.

Cations↗
PubMed2000

On-column surface-enhanced Raman spectroscopy detection in capillary electrophoresis using running buffers containing silver colloidal solutions

Direct on-column surface-enhanced Raman spectroscopy (SERS) detection is demonstrated in capillary electrophoresis (CE). Distinctive SERS spectra of two test compounds, riboflavin and Rhodamine 6G, are obtained in 100 microm i.d. fused-silica capillaries under CE conditions using running buffers that contain silver colloidal solutions. Detection is performed using an unmodified commercial Raman spectrometer in a confocal microscope mode of operation. The effects of laser power, wavelength, spectra acquisition time, silver colloidal concentration, and applied voltage (i.e., flow rate) on the quality of SERS spectra are evaluated. Using laser powers of 17 mW (at the sample) at 515 nm and employing 1 s spectral acquisition times, spectra with bands exhibiting signal-to-noise ratios greater than 10 could be obtained for 1.0 x 10(-6) M riboflavin and very low nanomolar concentrations of Rhodamine 6G. This was accomplished without optimization of silver colloidal solution compositions and by using a low-throughput spectrometer. Incorporation of the colloidal solutions into running buffers is shown to have little effect on the separation of the test compounds as monitored using a laser-induced fluorescence instrumental scheme. However, SERS spectra degrade if the capillary is not rinsed between experiments. Riboflavin and Rhodamine 6G spectra are obtained on-the-fly for actual CE separations. In the case of the latter solute, the injected quantity was approximately 90 amol.

Journal Article↗
PubMed2004

Differential electrolytic potentiometric determination of some thiol compounds in their dosage forms.

The application of direct current differential electrolytic potentiometry to an aqueous titration of L-cysteine hydrochloride, captopril and D-penicillamine has been investigated. The basic character of thiol compounds in nitric acid is enhanced to permit their direct titrations with silver nitrate. A pair of silver amalgam electrodes was used as an indicating system. Titration curve shapes obtained are almost symmetrical with sharp peaks. The optimum current density for those titrations was found to be 0.2-2 microA/cm2. The procedure was applied successfully to the determination of certain thiol compounds in drug formulations and the results were favorably compared statistically with those obtained from official methods.

Dosage Forms↗
PubMed1981

Backscattered electron imaging of human leukocytes.

Methods of backscattered electron imaging (BEI) have been applied to the study of normal and malignant human leukocytes. Four different elements, principally of high atomic number, have been used: iron, silver, lead and osmium. Iron, in the form of iron carbonyl, has been found to be an excellent marker for the phagocytic activity of granulocytes and monocytes. Silver staining permitted a clear observation of the shape of the nuclei and of the nucleo-cytoplasmic ratio and made the identification of polymorphonuclear cells and of certain normoblasts possible. Lead phosphate precipitates, deposited as a result of a classic acid phosphatase reaction, were detected in several cases of myelocytic and monocytic leukemias. Precipitates of osmium/diaminobenzidine complex on peroxidase-containing granules permitted the unambiguous identification of several classes of myeloid precursors. In all these techniques, the surface morphology of the cells was adequately preserved and could be correlated with the presence and/or the distribution of the various markers.

Acid Phosphatase↗
PubMed1983

Mercury chloride--and methyl mercury chloride--induced inhibition in NOR activity.

Previous work has raised the question of whether mercury compounds inhibit the activity of the nucleolar organizing genes. For that reason we performed a cytophotodensitometric analysis on silver-stained interphase nuclei from human peripheral blood lymphocytes exposed to various concentrations of HgCl2 (0-150 X 10(-6) M), CH3HgCl (0-50 X 10(-6) M), and actinomycin D (0-0.1 microgram/ml). The last compound was used as a positive control. The cells were exposed to the compounds either during G1-early S phase, allowing recovery after the exposure, or from G1 until harvest; thus no recovery was allowed in this case. Like actinomycin D, both mercury compounds were shown to inhibit the NOR activity. This inhibition was furthermore more evident during the short exposure experiment. Our results do confirm that mercury compounds may, to a certain extent, influence some factors regulating the nucleolus-organizing activity.

Adult↗
PubMed1989

[Effects of sealing of dentinal tubules of root canal wall with Ag (NH3)2F (3.8%) solution].

In this study, in order to determine a method for obtaining a good reaction, the reactive products of 3.8% Ag (NH3)2F, using formalin as a reducing agent, were studied. Saforide RC was used as the 3.8% Ag (NH3)2F solution and 10% neutral formalinsolution was used as a reducing agent. The silver mirror test and reaction products on the root canal wall were investigated under the scanning electron microscope, along with observation of dye penetration using a stereoscopic microscope. Reaction of periapical tissue to the materials was studied histologically in dogs. In the natural reduction group, less amounts of reactive products were seen, and sealing of the dentinal tubules of the root canal wall was inadequate. In the formalin reduction group, large amounts of reactive products were found, and the dentinal tubules of the root canal wall were sealed. CaF2, Ag3PO4, Ag2O and Ag were identified as reactive products. In the natural production groups, obstruction was present but incomplete. In Formalin groups, dye osmosis obstruction was recognized. No harmful action of the solution on the surrounding tissue of the dog's tooth was recognized.

Ammonium Compounds↗
PubMed2005

Redox-induced synthesis and encapsulation of metal nanoparticles in shell-cross-linked organometallic nanotubes.

A new approach to encapsulate silver nanoparticles inside block copolymer nanotubes is reported and involves an in situ redox reaction between a polyferrocenylsilane (PFS) inner wall and silver ions. Partial preoxidation of the PFS domains was found to be a key step for the efficient formation of one-dimensional arrays of silver nanoparticles confined within the nanotubes.

Ferrous Compounds↗