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Gold Coating (gold + coating)
Selected AbstractsGold Coating of Poly(ethylene terephthalate) Modified by Argon PlasmaPLASMA PROCESSES AND POLYMERS, Issue 1 2007Vladimír Kotál Abstract Little information has been published concerning the interaction of gold with polymers. In the context of this lack of information, we decided to investigate the effect of Ar plasma treatment on the surface properties of poly(ethylene terephthalate) (PET) in order to examine its possible application for metal-polymer adhesion improvement. The plasma treatment leads to an immediate increase of the PET's surface wettability, which however significantly depends on the sample aging, more specifically on the time elapsed after the treatment. X-ray photoelectron spectroscopy (XPS) measurements revealed that the oxygen concentration in the surface-near layers increases as a result of the treatment, but that it also changes with time for the samples in contact with the atmosphere, probably as a result of polar group rearrangements. Plasma initiated ablation and Au sputtering increases the surface roughness. The nanoindenter measurements revealed that the treatment increases the microhardness of treated PET. Contrary to hardness, the elastic modulus decreases. Scratch tests showed that the deformation of samples consisting of Au coatings deposited on both pristine and treated PET was elastic rather than plastic. We conclude from the nanoindenter data that the plasma modification does not affect the adhesion of gold on PET, but the X-ray diffractometry (XRD) analysis showed that the Au film deposited on the as-treated PET, and on PET aged for 14 d are the most stable. [source] Gold coating of non-conductive membranes before matrix-assisted laser desorption/ionization tandem mass spectrometric analysis prevents charging effectRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2005Alexander Scherl Acquisition of tandem mass spectra from peptides or other analytes deposited on non-conductive membranes is inhibited on instruments combining matrix-assisted laser desorption/ionization with tandem time-of-flight analyzers (MALDI-TOF/TOFÔ) due to a charging effect. A thin layer of gold renders the membrane conductive. This allows adequate data acquisition on MALDI-TOF/TOFÔ systems. Therefore, this methodology extends the capacity of the molecular scanner concept to tandem mass spectrometry. Copyright © 2005 John Wiley & Sons, Ltd. [source] Gold coating and restenosis after primary stenting of ostial renal artery stenosisCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2003Thomas Zeller MD Abstract Predictors of restenosis after stent angioplasty of ostial renal artery stenosis (RAS) and long-term technical success, particularly the influence of gold coating, are unknown. During a 4-year period (1996,2000), we treated 156 consecutive patients with 219 ostial RAS of , 70% diameter stenosis. Gold-coated stents were used in 29% of RAS (n = 64); the vessel diameter ranged from 3 to 9 mm. The restenosis rate was 11.4% at 12 months, 12.2% for gold-coated stents and 11.1% for noncoated stents. Restenosis rates were 16% for , 4 mm, 17% for 5 mm, 10% for 6 mm, and 0% for , 7 mm (P , 0.05). In a backward stepwise logistic regression analysis including gold coating, vessel diameter, gender, diabetes, smoking status, as well as lesion diameter stenosis before and after stenting, vessel diameter was found the only independent predictor of restenosis (odds ratio = 0.57; 95% CI = 0.35,0.93; P = 0.02, for an increase in vessel diameter of 1 mm). Gold coating was not a significant predictor (odds ratio = 1.09; 95% CI = 0.39,3.03; P = 0.87). Seven major (4.5%) complications occurred. There were no procedural fatalities. The restenosis rate after stent angioplasty of ostial RAS is influenced by the vessel diameter but not by gold coating. Catheter Cardiovasc Interv 2003;60:1,6. © 2003 Wiley,Liss, Inc. [source] Monte Carlo Study of Quantitative Electron Probe Microanalysis of Monazite with a Coating Film: Comparison of 25 nm Carbon and 10 nm Gold at E0= 15 and 25 keVGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 2 2007Takenori Kato simulation par la méthode de Monte Carlo; microanalyse par sonde électronique (EPMA); analyse quantitative; film de revêtement; monazite Carbon (25,30 nm in thickness) is the most common coating material used in the electron probe microanalysis (EPMA) of geological samples. A gold coating is also used in special cases to reduce the surface damage by electron bombardment. Monte Carlo simulations have been performed for monazite with a 25 nm carbon and a 10 nm gold coating to understand the effect of a coating film in quantitative EPMA at E0= 15 keV and 25 keV. Simulations showed that carbon-coated monazite gave the same depth distribution of the generated X-rays in the monazite as uncoated monazite, whilst gold-coated monazite gave a distorted depth distribution. A 10 nm gold coating was 1.06 (15 keV) and 1.05 (25 keV) times higher in k -ratio between monazite and pure thorium than a 25 nm carbon coating at an X-ray take-off angle of 40 degrees. Thus, a 10 nm gold coating is a possible factor contributing to inaccuracy in quantitative EPMA of monazite, while a 25 nm carbon coating does not have a significant effect. Le carbone, avec des épaisseurs de 25 à 30 nm, est le matériel de dépôt le plus fréquemment utilisé en microanalyse par sonde électronique (EPMA) d'échantillons géologiques. Un dépôt d'or est aussi utilisé dans des cas spécifiques, pour réduire les dommages causés à la surface par le bombardement d'électrons. Des simulations par la méthode de Monte Carlo ont été effectuées pour une monazite recouverte d'une couche de carbone de 25 nm et d'une couche d'or de 10 nm, dans le but de comprendre l'effet du dépôt dans les mesures quantitatives à l'EPMA, à E0= 15 keV et 25 keV. Les simulations ont montré que la monazite recouverte de carbone avait la même distribution en profondeur de rayons X générés qu'une monazite non recouverte, tandis que la monazite recouverte d'or avait une distribution en profondeur déformée. Le dépôt de 10 nm d'or avait un k -ratio qui était 1.06 (pour 15 keV) et 1.05 (pour 25 keV) fois plus important pour la monazite et du thorium pur que le dépôt de 25 nm de carbone dans le cas d'un angle de sortie des rayons X de 40 degrés. En conséquence un dépôt d'or de 10 nm est un facteur possible d'inexactitude lors de mesures quantitatives de monazites par EPMA, alors qu'un dépôt de carbone de 25 nm n'a pas d'effet significatif sur la mesure. [source] The molecular scanner in microscope modeRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2006Stefan L. Luxembourg The combination of microscope mode matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) with protein identification methodology: the molecular scanner, was explored. The molecular scanner approach provides improvement of sensitivity of detection and identification of high-mass proteins in microscope mode IMS. The methodology was tested on protein distributions obtained after separation by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE). High-quality, high-spatial-resolution ion images were recorded on a TRIFT-II ion microscope after gold coating of the MALDI sample preparation on the poly(vinylidenedifluoride) capture membranes. The sensitivity of the combined method is estimated to be 5 pmol. The minimum amount of sample consumed, needed for identification, was estimated to be better than 100 fmol. Software tools were developed to analyze the spectral data and to generate broad mass range and single molecular component microscope mode ion images and single mass-to-charge ratio microprobe mode images. Copyright © 2006 John Wiley & Sons, Ltd. [source] Gold-coated fused-silica sheathless electrospray emitters based on vapor-deposited titanium adhesion layersRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2003Stefan Nilsson Gold-coated fused-silica electrospray (ES) emitters based on vapor-deposited adhesion layers of titanium have been manufactured to investigate the possibilities of producing durable ES emitters applicable in chip-based analytical devices. The stabilities of the emitters were studied by both electrospray and electrochemical experiments and a marked increase in the emitter lifetime, compared to that for Cr/Au coated emitters, was found for the Ti/Au emitters in the ES durability tests. This indicates that Ti (rather than Cr) adhesion layers should be used in association with large-scale fabrication of ES emitters by vapor-deposition techniques. The lifetime of about 500,700 hours also allowed the Ti/Au-coated emitter to be used as an integrated part of a capillary liquid chromatography column coupled to a mass spectrometer in a series of LC/MS experiments. The Ti/Au coating was further studied by electrochemical techniques and scanning electron microscopy in conjunction with X-ray spectroscopy. It is shown that the eventual failure of the Ti/Au emitters in ES experiments was due to an almost complete detachment of the gold layer. Experimental evidence suggests that the detachment of the gold coating was due to a reduced adhesion to the titanium layer during oxidation in positive electrospray. Most likely, this was caused by the formation of an oxide layer on the titanium film. It is thus shown that unlimited emitter stabilities are not automatically obtained even if the metallic adhesion layer is stabilized by an oxide formation under positive electrospray conditions. Copyright © 2003 John Wiley & Sons, Ltd. [source] Gold coating and restenosis after primary stenting of ostial renal artery stenosisCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2003Thomas Zeller MD Abstract Predictors of restenosis after stent angioplasty of ostial renal artery stenosis (RAS) and long-term technical success, particularly the influence of gold coating, are unknown. During a 4-year period (1996,2000), we treated 156 consecutive patients with 219 ostial RAS of , 70% diameter stenosis. Gold-coated stents were used in 29% of RAS (n = 64); the vessel diameter ranged from 3 to 9 mm. The restenosis rate was 11.4% at 12 months, 12.2% for gold-coated stents and 11.1% for noncoated stents. Restenosis rates were 16% for , 4 mm, 17% for 5 mm, 10% for 6 mm, and 0% for , 7 mm (P , 0.05). In a backward stepwise logistic regression analysis including gold coating, vessel diameter, gender, diabetes, smoking status, as well as lesion diameter stenosis before and after stenting, vessel diameter was found the only independent predictor of restenosis (odds ratio = 0.57; 95% CI = 0.35,0.93; P = 0.02, for an increase in vessel diameter of 1 mm). Gold coating was not a significant predictor (odds ratio = 1.09; 95% CI = 0.39,3.03; P = 0.87). Seven major (4.5%) complications occurred. There were no procedural fatalities. The restenosis rate after stent angioplasty of ostial RAS is influenced by the vessel diameter but not by gold coating. Catheter Cardiovasc Interv 2003;60:1,6. © 2003 Wiley,Liss, Inc. [source] Electrochemical Modulation of Remote Fluorescence Imaging at an Ordered Opto-electrochemical Nanoaperture ArrayCHEMPHYSCHEM, Issue 8 2004Arnaud Chovin Abstract An array of nanometer-sized apertures capable of electrochemically modulating the fluorescence of a model analyte is presented. The device, which combines near-field optical methods and ultramicroelectrode properties in an array format, is based on an etched coherent optical fiber bundle. Indeed, the fabrication steps produced an ordered array where each optical nanoaperture is surrounded by a ring-shaped gold nanoelectrode. The chronoamperometric behavior of the array shows stable diffusion-limited quasi-steady-state response. The model analyte, tris(2,2,-bipyridine) ruthenium, emits fluorescence in the Ru(II) state, but not in the oxidized Ru(III) state. Fluorescence is excited by visible light exiting from each nanoaperture since light is confined to the tip apex by the gold coating. A fraction of the isotropically emitted luminescence is collected by the same nanoaperture, transmitted by the corresponding fiber core and eventually detected by a charge-coupled device (CCD) camera. The array format provides a fluorescence image resolved at the nanometric scale which covers a large micrometric area. Therefore the high-density array plays a bridging role between these two fundamental scales. We established that the opto-electrochemical nanoapertures are optically independent. Fluorescence of the sample collected by each nanoaperture is modulated by changing the potential of the nanoring electrodes. Reversible electrochemical switching of remote fluorescence imaging is performed through the opto-electrochemical nanoaperture array itself. Eventually this ordered structure of nanometer light sources which are electrochemically manipulated provides promising photonic or electro-optical devices for various future applications. For example, such an array has potential in the development of a combined SNOM-electrochemical nanoprobe array to image a real sample concomitantly at the nanometer and micrometer scale. [source] REMOVING GOLD COATING FROM SEM SAMPLESPALAEONTOLOGY, Issue 6 2007STEPHEN A. LESLIE Abstract:, An essential tool in micropalaeontological studies is analysis and imaging using a scanning electron microscope (SEM). It is commonly necessary to coat the sample with a thin layer of gold or gold-palladium alloy in order to prevent charging of the surface, to promote the emission of secondary electrons so that the specimen conducts evenly, and to provide a homogeneous surface for analysis and imaging. However, coating a specimen with gold is a semi-destructive process that masks the surface of specimens, and a common curatorial practice is to prohibit coating of important specimens. We describe a non-destructive, simple and inexpensive technique that uses KCN (or NaCN), a glass jar, paper towels, cardboard and a fume hood for the removal of gold coatings from SEM samples. This technique requires little additional handling of the specimen, and there is no need to place the specimen in a solution. [source] | |||||||||||||