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 523 records · Page 29Linked to original sources
PubMed2004

Simultaneous real-time amperometric measurement of catecholamines and serotonin at carbon fibre 'dident' microelectrodes.

Amperometry allows real-time measurement of in vivo electrochemical signals, albeit with no capacity to identify the constituents of the signal. In the present study, differential amperometry was used to monitor catecholamine and serotonin (5-HT) simultaneously at the same location. 'Dident' carbon fibre microelectrodes (microelectrodes with two working electrodes in a single assembly) were constructed and coated with Nafion to prevent poisoning on contact with brain tissue. One electrode (channel A) was held at +200 mV versus Ag/AgCl to monitor catecholamines selectively. This potential is too low to oxidise 5-HT. The second electrode (channel B), recording faradaic current at +500 mV versus Ag/AgCl, measured the sum of catecholamine and 5-HT oxidation. The 5-HT current component was the difference of channel B minus channel A. With appropriate balancing of the two channels, it is possible to record catecholamines and 5-HT simultaneously at the same dident microelectrode. Examples of measurements in striatum, cortex and locus coeruleus are shown.

Animals↗
PubMed2007

A silver-impregnated antimicrobial dressing reduces hospital costs for pediatric burn patients.

PURPOSE: Since using a novel silver-impregnated antimicrobial dressing (Aquacel Ag, ConvaTec, Princeton, NJ) in our pediatric patients with partial-thickness burns, hospital LOS has been significantly reduced. Here we investigated whether there was concomitant cost-effectiveness of this approach. METHODS: We retrospectively reviewed Burn Registry Data from a large Children's Hospital Burn Unit from January 2005 through August 2005 for inpatients with partial-thickness burns treated with Aquacel Ag. A comparison group was composed of patients from the same period the previous year treated with silver sulfadiazine cream (SSD, Par Pharmaceuticals, Woodcliff, NJ) and matched for age and %TBSA burned. Patients with inhalation injury or full-thickness burns were excluded. Intent-to-treat analysis was limited to patients with less than 22% TBSA burn. Direct costs and total charges were compared statistically after log transformation due to the skewedness of the data. RESULTS: Total charges and direct costs were significantly lower for Aquacel Ag-treated patients (n = 38) than for SSD-treated patients (n = 39) (P = .004 and P < .001, respectively). In addition, Aquacel Ag-treated patients had a shorter LOS than SSD-treated patients. DISCUSSION: These data strongly support our findings that the application of Aquacel Ag reduces hospital LOS which results in a significant cost savings in the care of pediatric patients with partial-thickness burns.

Anti-Infective Agents, Local↗
PubMed2005

Effect of an adhesive resin luting agent on the dowel-head retention of three different core materials.

STATEMENT OF PROBLEM: A dowel-and-core restoration may fail due to failure at either the dowel-tooth or dowel head-core material interface. Long-term clinical success of a dowel-and-core restoration depends on retention of both the dowel to the tooth and the dowel head to the core material. Thus, strengthening of the dowel head-core interface is important. PURPOSE: This study evaluated the retention between a prefabricated dowel and 3 different core materials with or without a dual-polymerized adhesive resin luting agent. MATERIAL AND METHODS: Sixty prefabricated dowels (Gold Plated Anchorage Post) were divided into 3 groups (n=20) consisting of 1 of 3 core materials, amalgam (Standalloy F), light-polymerized resin composite (Clearfil Ray), or glass ionomer (Chelon-Silver). Each core group was divided into 2 subgroups (n=10), and a dual-polymerized adhesive resin luting agent (Panavia F) was applied to the dowel heads of 1 of these subgroups before application of the core material. The manufacturing procedure was standardized by using a plastic index (4.5-mm internal diameter and 5-mm height) and a custom-made dowel holder, which held the dowel head. Prepared specimens were stored in water at room temperature for 3 months and then loaded to fracture in a universal testing machine with a crosshead speed of 0.05 mm/min until failure. Bond strengths were recorded (MPa). Data were analyzed with 2-way analysis of variance (ANOVA) in a 2 x 3 factorial randomized design (alpha=.05). Afterward, core material differences were computed with 1-way ANOVA for both of the bonded and nonbonded groups. Post hoc multiple comparisons were made with the Dunnett C multiple range test. RESULTS: Dowel-head retention values (MPa) of the tested core materials (mean +/- SD) from the highest to the lowest were as follows: bonded amalgam core, 296.1 +/- 108; bonded composite core, 284.3 +/- 38.3; nonbonded composite core, 177.0 +/- 53.7; nonbonded amalgam core, 128.5 +/- 35.0; bonded glass-ionomer core (GIC), 128.0 +/- 24.5; nonbonded GIC, 61.8 +/- 13.3. Two-way ANOVA revealed significant differences between the core material groups and between the bonded and nonbonded groups (P <.001). The interaction between the core material and bond variables was also significant (P =.018). One-way ANOVA revealed statistically significant differences between the bonded (P <.001) and also between the nonbonded core material groups (P <.001). Post hoc multiple comparisons showed that the dowel-head retention of the GIC was significantly weaker than the post-head retention for amalgam and resin composite, whether bonded or not. CONCLUSION: Within the limitations of this study, the adhesive resin luting agent tested appeared to have a significant strengthening effect on the dowel-head retention of the core materials.

Adhesives↗
PubMed2005

Vibrational spectra of saccharin nitranion and its orientation on the surface of silver metal particles.

Infrared-reflectance spectra of the saccharin nitranion adsorbed on silver powder was observed. Surface-Enhanced Raman Scattering (SERS) spectra of the saccharin nitranion were also recorded using cellulose acetate films doped with fine silver particles. The spectra suggested that the saccharin nitranion is bonded to the silver metal surface through the oxygen atom of carbonyl and the nitrogen atom of the imide ring groups and that the nitranion tilts at the surface.

Acetates↗
PubMed2005

Conformational analysis and comparison between theoretical and experimental vibration spectra for isocyanate species on Ag/Al2O3 catalyst.

Density functional theory (DFT) calculations were performed to study the structure and vibrational frequencies of the intermediate for the isocyanate (NCO) surface species on Ag/Al(2)O(3) catalyst using the GAUSSIAN 98 suite of programs. Thermal decomposition of adsorbed CH(3)NO(2) species leads to the formation of two types of NCO species (NCO on Ag and NCO on Al(2)O(3)) above 298K. In order to investigate the reaction mechanism, we have designed the calculated models (a-g) for the NCO intermediate. Through the analysis of the vibration mode and the vibration frequency of the calculated models (a-g), we conclude that there is an excellent agreement between the calculated vibration spectrum of the model (e) containing the -AgNCO group or model (g) containing the -AlNCO group and the experimental vibration spectrum.

Aluminum Oxide↗
PubMed2005

Effect of silver nanowires on the surface-enhanced Raman spectra (SERS) of the RNA bases.

RNA bases have a great importance in the biological and genetics applications. The surface-enhanced Raman scattering (SERS) was used to study the orientation and adsorption structure of RNA bases adsorbed on the surface of silver nanowires (Ag NWs). The Ag NWs were prepared and its UV-vis spectra were recorded. The RNA bases oriented perpendicularly on the surface of Ag NWs, as the coverage area decreases. Consequently, the in-plane bands were enhanced according to the SERS selection rule. Many bands were red shifted due to the chemisorption of RNA bases on the Ag NWs surface. New bands corresponding to the base-surface bond were appeared in the SERS spectra.

Adenine↗
PubMed2006

FT-IR, FT-Raman and SERS spectra of pyridine-3-sulfonic acid.

FT-IR and FT-Raman spectra of pyridine-3-sulfonic acid are recorded and analysed. Surface enhanced Raman scattering (SERS) spectrum is recorded in a silver colloid. The bands due to upsilonCH, upsilonSO are enhanced in the SERS spectrum. A likely 'perpendicular orientation' of the molecule on the silver surface is suggested.

Colloids↗
PubMed2006

Solid and solution NMR studies of the complexation of Ag+ with the trans isomer of captopril: biological activities of this high blood pressure drug along with its Ag+ complex.

Complexation of Ag(+) with captopril, 1-[(2S)-3-mercapto-2-methylpropionyl]-L-proline, has been studied by (1)H and (13)C-NMR spectroscopy. The equilibrium constants for the trans to cis isomers of captopril bound to Ag(+) were measured by (1)H NMR spectroscopy. It is observed that the trans isomer of the drug binds more strongly to Ag(+) between pH 5 and 8, as shown by the broadening of the trans isomer's resonances in (13)C NMR spectra on complexation. A monodentate complexation of the trans captopril with Ag(+) via the thiol site is proposed based on the solid-state NMR and IR data. A superior antimicrobial activity is exhibited by the Cap-Ag(I) complex compared to captopril ligand itself against Heterotrotropic Plate Counts (HPC), Pseudomonas aeruginosa and Fecal streptococcus bacteria.

Anti-Infective Agents↗
PubMed2004

Simultaneous release of sulfide with Fe, Mn, Ni and Zn in marine harbour sediment measured using a combined metal/sulfide DGT probe.

The technique of DGT (Diffusive Gradients in Thin Films) was further developed to allow simultaneous measurement of sulfide and trace metals at the same location in sediment. The new combined DGT probe consisted of a layer of gel impregnated with AgI, overlain by (1) a layer of gel containing Chelex, (2) a layer of gel and (3) a filter membrane. Diffusion of sulfide was controlled by layers (1) to (3), while diffusion of metals was controlled by layers (2) and (3). The Chelex gel trapped metals that were measured after elution with acid. The AgI gel trapped sulfide through the formation of Ag2S. This was then measured densitometrically as the colour changed from pale yellow to grey. Experiments demonstrated that concentrations of metal or sulfide measured by the combined device were no different to the concentrations measured by more conventional devices. The presence of Chelex in the gel did not impede the diffusion of sulfide. Deployment of a combined probe in marine sediment revealed simultaneous remobilisation of metals and sulfide at the same location. Solubility calculations indicated that some precipitation of amorphous FeS was probably occurring at the maxima in sulfide concentrations. There was general undersaturation with respect to NiS, but ZnS was supersaturated at all locations. There appeared to be localised active zones of organic matter decomposition, where reduction of manganese oxides, iron oxides and sulfate occurred simultaneously. Mass balance calculations indicated that Ni could not be supplied by release from decomposing organic matter. Manganese oxides were the most likely source, but supply from reductive dissolution of iron oxides could not be entirely discounted. Supply from either Fe or Mn oxides could account for the Zn maxima. Application of the newly developed combined probe provides new information that helps understanding of the complex nature of trace metal and sulfur chemistry in sediments.

Chemistry Techniques, Analytical↗
PubMed2005

Potential kinetic availability of metals in sulphidic freshwater sediments.

The insolubility of metal sulphides is believed to limit the bioavailability of trace metals in sulphidic sediments. However, if non-equilibrium conditions are important, metals may be more available than simple thermodynamic calculations suggest. To investigate the possible dynamic supply of Cu, Ni and Zn in a sulphidic freshwater sediment, they were measured, along with iron, manganese and sulphide, by the technique of diffusive gradients in thin-films (DGT). DGT measures the supply of solute from sediment to solution in response to a local solute sink. Release of Mn, Cu, Zn and Ni was observed at the sediment surface and attributed to the supply from reductive dissolution of manganese oxides. The depth profile of simultaneously extractable metals (SEM) for Cu and Ni followed the shape of the Mn profile more closely than the profiles of either acid volatile sulphur (AVS) or Fe, again consistent with supply from Mn oxides. Solubility calculations for a mesocosm of homogenised sediment indicated supersaturation with respect to the sulphides of Fe, Cu, Ni and Zn, yet DGT measurements demonstrated a substantial supply of both trace metals and sulphide from the solid phase to the pore waters. Ratios of metals measured in pore waters by DGT were consistent with their release from iron and manganese oxides, indicating that supply, as much as removal processes, determines the pseudo-steady state concentrations in the pore waters. The observations suggest that trace metals are not immediately bound in an insoluble, inert form when they are in contact with sulphide. This has consequences for modelling metal processes in sediment, as well as for uptake by some biota.

Acrylic Resins↗
PubMed2005

Leaching of silver from solid waste using ultrasound assisted thiourea method.

Thiourea leaching of precious metals such as gold and silver from ores has several advantages when compared with conventional cyanidation process. In recent years, the use of ultrasound in leaching processes is becoming increasingly popular in hydrometallurgy. This paper deals with combining these two techniques for silver leaching from solid waste of a cyanidation leach plant located in Kutahya, Turkey. The primary aim of this research is to assess the technical performance of the method. To achieve maximum leaching yield, eight process variables have been selected to estimate optimum process conditions by means of statistical factorial design and steepest ascent techniques. Laboratory-scale experiments showed that complete leaching of silver may be achieved by this process.

Algorithms↗
PubMed2006

Hydroxyapatite-supported Ag-TiO2 as Escherichia coli disinfection photocatalyst.

A series of hydroxyapatite (HAP), 1wt% Ag-TiO(2) (AT1), 1wt% Ag-HAP and 5wt% AT1/HAP composite catalysts were prepared by incipient wetness and mechanical mixing methods. They were characterized by X-ray diffraction (XRD), FT-IR, SEM and ESCA analyses and their photocatalytic bactericidal activities were measured in suspension using Escherichia coli (E. coli), a water pollutant indicator. The surface analysis revealed that the Ag/Ti ratio is found to be ca. 0.0273 and also it indicated that the titania is present in the form of Ti(4+) and Ag is present as metallic silver. Both the XRD and ESCA analyses confirmed the phase of metallic Ag particles, which played a significant role on the bactericidal activity of the Ag doped TiO(2) catalysts. The FT-IR analysis of HAP revealed that the peak intensity is due to the absorbance of surface PO(4)(3-) group centered at wave number 1030cm(-1) and is drastically decreased upon exposure to UV for 1h. The HAP displayed high amount of bacteria adsorption, ca. 80% during the dark experiments compared to other catalytic systems tested. The cumulative photocatalytic properties of AT1/HAP catalytic system resulted in 100% E. coli bacteria reduction within 2min.

Adsorption↗
PubMed2001

Metallothionein in human gingival amalgam tattoos.

Amalgam tattoos occur when small particles of dental amalgam, composed largely of silver (Ag) and mercury (Hg), are inadvertently implanted into oral soft tissues during dental procedures. Metallothioneins (MTs) are ubiquitous, low molecular weight, cysteine-rich, metal-binding proteins that are inducible by many agents including metals and may be involved in the detoxification of toxic metals such as Hg. In this study, the correlation between MT expression and amalgam tattoos in human gingiva was investigated using energy-dispersive X-ray microanalysis (EDX) and immunohistochemical techniques. Light microscopically, amalgam tattoos presented as either fine granular particles or larger discrete opaque globular particles in connective tissues. EDX revealed the smaller particles to be silver sulphide (Ag(2)S), while the larger particles exhibited a shell of Ag(2)S that contained irregularly distributed masses of Ag and Hg. Particles of tin (Sn) were also found. No MT staining was observed in collagen, fibroblasts or blood vessels in areas exhibiting abundant amounts of embedded fine granular Ag(2)S particles. Blood vessels exhibiting relatively few amalgam particles stained positively for MT. Cells with the morphological features of histiocytes located directly adjacent to larger pieces of amalgam showed intense MT staining. These results indicate that amalgam tattoos contain no Hg or free Ag except in large globular pieces of amalgam, which still contain Hg and which induce MT expression in adjacent histiocytes. This suggests that Hg leaching from impacted dental amalgam particles induces MT, while residual Ag(2)S and Sn particles do not. MT may therefore act to reduce Hg exposure in patients with amalgam tattoos.

Blood Vessels↗
PubMed1992

Syntheses of specifically deoxygenated methyl alpha-isomaltotriosides.

Specifically deoxygenated methyl alpha-isomaltotriosides were synthesized by the silver perchlorate-mediated condensation of a protected alpha-isomaltosyl chloride with suitably blocked derivatives of methyl alpha-D-glucopyranoside deoxygenated respectively at positions 2, 3, and 4, followed by deprotection.

Carbohydrate Sequence↗