Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Electroplating”

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 199 records · Page 11Linked to original sources
PubMed2004

Quantitative determination of hydrogen in solids by gas chromatography.

Processes such as electroplating or acid cleaning are notorious causes of post-processing failure through hydrogen embrittlement. So, the determination of amounts of hydrogen in metals is of great importance. An analysis method for investigation of H content in solids has been established based on hot extraction and gas chromatography system. Hot extraction in inert gas enables complete and/or partial removal of the hydrogen from the samples. A gas chromatography system is used to determine quantitatively the amount of thermally desorbed hydrogen. An investigation of the baking operating conditions is made of the hydrogen desorption rate of zinc-plated steel parts. Then, an analysis of the polarisation conditions upon chromium electroplating is given.

Calibration↗
PubMed2003

Adsorption of polyethylene glycol (PEG) from aqueous solution onto hydrophobic zeolite.

In the present study, a hydrophobic zeolite was used as an adsorbent for the adsorption of polyethylene glycol (PEG) in water solution and electroplating solution at 25 degrees C. The adsorption capacities were determined through the adsorption isotherms in a thermostated shaker. The rate of adsorption, on the other hand, was investigated in a batch adsorber under controlled process parameters such as initial PEG concentration (30, 70, 110, 150, 200, and 300 mg x dm(-3)), agitation speed (200, 800, and 1000 rpm), and adsorbent particle size (0.72, 1.44, and 2.03 mm). A batch kinetic model, according to a pseudo-second-order mechanism, has been tested to predict the rate constant of adsorption, equilibrium adsorption capacity, time of half-adsorption, and equilibrium concentration by the fitting of the experimental data. The results of the adsorption isotherm and kinetic studies show that the adsorption process can well be described with the Langmuir and Freundlich models and the pseudo-second-order equation, respectively. Comparing the values of adsorption parameters of PEG in water solution and electroplating solution, there are no significant differences. In addition, the effective diffusion coefficient of the PEG molecule in the microporous adsorbent has been estimated at about 3.20 x 10(-8) cm(2)s(-1) based on the restrictive diffusion model.

Journal Article↗
PubMed2003

Production of therapeutic quantities of (64)Cu using a 12 MeV cyclotron.

(64)Cu is a useful radiotracer for positron emission tomography (PET) and a promising radiotherapy agent for the treatment of cancer. Recently, (64)Cu-labeled radiopharmaceuticals were reported to be useful for internal radiation therapy as well as PET monitoring of tumors.(64)Cu was produced at the Fukui Medical University's cyclotron using twelve MeV proton irradiation and the (64)Ni(p,n) (64)Cu nuclear reaction. A (64)Ni target was electroplated on a gold disk at a thickness of 50 to > 100 microm. Electroplating was performed at 2.5 V, at currents between 5-15 mA, and was completed in 12-24 hr. The (64)Ni target was bombarded with a 50 +/- 3 microA proton current. After bombardment, (64)Cu was separated from the (64)Ni target and other contaminants using an anion exchange column. Target (64)Ni was recovered and re-used. The yield of (64)Cu was 0.6 to > 3.0 mCi/microA*h, and averaged 1.983 mCi/microA*h. The radionuclidic purity of (64)Cu was over 99%. In this study, we obtained sufficient qualities and quantities of (64)Cu for therapeutic application and dose monitoring using PET using an ultra-small cyclotron.

Copper Radioisotopes↗
PubMed1997

Efficient production of high specific activity 64Cu using a biomedical cyclotron.

Copper-64 (T 1/2 = 12.7 h) is an intermediate-lived positron-emitting radionuclide that is a useful radiotracer for positron emission tomography (PET) as well as a promising radiotherapy agent for the treatment for cancer. Currently, copper-64 suitable for biomedical studies is produced in the fast neutron flux trap (irradiation of zinc with fast neutrons) at the Missouri University Research Reactor. Access to the fast neutron flux trap is only possible on a weekly basis, making the availability of this tracer very limited. In order to significantly increase the availability of this intermediate-lived radiotracer, we have investigated and developed a method for the efficient production of high specific activity Cu-64 using a small biomedical cyclotron. It has been suggested that it may be possible to produce Cu-64 on a small biomedical cyclotron utilizing the 64Ni(p,n)64Cu nuclear reaction. We have irradiated both natural nickel and enriched (95% and 98%) Ni-64 plated on gold disks. Nickel has been electroplated successfully at thicknesses of approximately 20-300 mm and bombarded with proton currents of 15-45 microA. A special water-cooled target had been designed to facilitate the irradiations on a biomedical cyclotron up to 60 microA. We have shown that it is possible to separate Cu-64 from Ni-64 and other reaction byproducts rapidly and efficiently by using ion exchange chromatography. Production runs using 19-55 mg of 95% enriched Ni-64 have yielded 150-600 mCi of Cu-64 (2.3-5.0 mCi/microAh) with specific activities of 94-310 mci/microgram Cu. The cyclotron produced Cu-64 had been used to radiolabel PTSM [pyruvaldehyde bis-(N4-methylthiosemicarbazone), used to quantify myocardial, cerebral, renal, and tumor blood flow], MAb 1A3 [monoclonal antibody MAb to colon cancer], and octreotide. A recycling technique for the costly Ni-64 target material has been developed. This technique allows the nickel eluted off the column to be recovered and reused in the electroplating of new targets with an overall efficiency of greater than 90%.

Copper Radioisotopes↗
PubMed2000

Fabrication of metallic microstructures using exposed, developed silver halide-based photographic film

This paper demonstrates that the pattern of silver particles embedded in the gelatin matrix of exposed and developed silver halide-based photographic film can serve as a template in a broadly applicable method for the microfabrication of metallic microstructures. In this method, a CAD file is reproduced in the photographic film by exposure and developing. The resulting pattern of discontinuous silver grains is augmented and made electrically continuous by electroless deposition of silver, and the electrically continuous structure is then used as the cathode for electrochemical deposition of an additional layer of the same or different metal. The overall process can be completed within 2 h, starting from a CAD file, and can generate electrically continuous structures with the smallest dimension in the plane of the film of approximately 30 microns. Structures with aspect ratio of up to 5 can also be obtained by using the metallic structures as photomasks in photolithography using SU-8 photoresist on the top of the electroplated pattern and exposed from the bottom, followed by development and electroplating through the patterned photoresist. This method of fabrication uses readily available equipment and makes it possible to develop prototypes of a wide variety of metallic structures and devices. The resulting structures--either supported on the film backing or freed from it--are appropriate for use as passive, structural materials such as wire frames or meshes and can also be used in microfluidic, microanalytical, and microelectromechanical systems.

Journal Article↗
PubMed1989

Bioassay alpha spectrometry: energy resolution as a function of sample source preparation and counting geometry.

Alpha particle counting is based on the response of an electronic counting system to an incident alpha particle. Alpha spectrometry is used in our employee surveillance bioassay program to measure the concentration of isotopes of Am, Pu and U contained on sample source preparations. Nuclides of Am, Pu and U are separated from the sample matrix by anion exchange and are electroplated on a stainless steel disc (Gautier and Gladney 1986). The plated source diameter is 12.7 mm. A tracer is added to the sample before anion exchange as a quality control procedure to provide a measure of chemical yield. Tracer alpha-particle emissions are recorded in a preassigned calibrated area of the energy spectrum and chemical recovery is calculated by the ratio of tracer counts per second divided by the tracer activity in becquerels (Bq). Percent tracer recovery may also be calculated by introducing the average counting efficiency factor in the denominator. Tracer yield is then used to provide a reliable estimate of the sample's analyte counts that are recorded in other preassigned energy dependent areas of the spectrum. The tracer spectrum in the presence or absence of other nuclides also provides evidence of the performance characteristics of the alpha spectrometer, for example, chamber vacuum and electronics. Electroplated samples are counted in any one of 96 detectors. The backgrounds of these detectors are maintained at less than 3 counts per 70,000 s over a 190 keV energy window to provide a limit of detection of less than 0.37 mBq per sample at the 95% confidence level. In this paper, resolution of the photopeak is shown to be a function of the source to detector distance and a function of degraded alpha energies due to Fe or other extraneous materials on the plated surface. Since our program is concerned only with low activity samples (less than 0.2 Bq) we encounter no significant problem with tailing when the resolution is less than 50 keV FWHM.

Alpha Particles↗
PubMed2005

[Highly sensitive spectrofluorimetric determination of trace amounts of chromium (VI) with mono[6-o-(4-aminobenzoic acid)]-beta-cyclodextrin].

A novel fluorescence probe, mono[6-o-(4-aminobenzoic acid)]-beta-cyclodextrin(ACD), was synthesized, and a new sensitive fluorescence identification reaction was studied based on the reaction of Cr2O7(2-) with compound ACD in NaAc-HAc buffer medium at pH 4.90. Under optimal conditions the determination limit was 1.26 microg x L(-1). The linear range was 5.20-1040 microg x L(-1). This method has been applied to the determination of trace amounts of chromium (VI) in electroplating liquor, electroplating waste water with satisfactory results.

Chromium↗
PubMedDate not supplied

[Occupational exposure to nickel in Tuscany: analysis of a biological monitoring register for the period 1991-1998].

OBJECTIVE: The study assesses the time trend in exposure to nickel among factory workers in Florence, via data on biological monitoring. A data-base of nickel in urinary samples (Ni-U mg/l) was created for the period 1991 to 1998. METHODS: The data-base contained 2.138 samples, measured by atomic absorption (GF-AAS),from 893 workers. Subjects came from 157 factories in various manufacturing sectors, especially electroplating, mechanical workshops, jewellery. RESULTS: Ni-U levels were correlated with manufacturing sector. The highest levels were found among workers from electroplating industries, where exposure was mainly due to water-soluble nickel compounds. The eight-year time trend showed a statistically significant decrease in Ni-U values, with a sharper drop during the last two-year period. Age, sex and number of samples per subject were not statistically related to this trend. CONCLUSION: The observed Ni-U decrease could be related to the efficacy of new legislation introduced in Italy during the study period (Law 626/94 and subsequent laws), but also to the intense labour inspection activities that officials of National Health Service performed, which were rightly focused on nickel exposure in different manufacturing sectors. This study confirms the usefulness for occupational risk evaluation of a biological monitoring data-base of routinely collected data.

Adult↗
PubMed1989

[Validation and practice of the clinical use of lateral galvanization in combined therapy of habitual abortion].

Efficacy of routine treatment and lateral electroplating was comparatively assessed in 60 females with a history of habitual abortion. More infrequent complications, lower maternal and fetal drug exposure, increased number of pregnancy continuation up to a fullterm delivery and shorter periods of needed hospitalization be regarded as benefits of electroplating techniques. The method simplicity provides for its use both on out- and inpatient bases.

Abortion, Habitual↗
PubMed1979

Activated silver coatings for surgical implants.

Increase in current from 1.8 to 3 and then to 9 microAH+DC/cm2 controlled respectively 25%, 37%, and 69% of S aureus on intramedullary silver pins (too soft in practice) in femurs of rabbits. Then optimal current of 12 muAH+DC/cm2 was used. On stainless steel pins with intramedullary injection of AgCl or AgNO3, a 25% or 64% bacterial control was achieved. Stainless steel pin, silver electroplated or electroplated and chloridized gave 85% and 91% bacterial control. One hundred percent of the bacteria was eliminated with stainless steel pins coated with 100 monomolecular layers of silver stearate.

Animals↗
PubMed1984

[Alpha-recoiling behaviour of 222Rn on 226Ra-sources].

By using electroplated 226Ra-sources, the ejection and injection behaviour of alpha-recoil atoms, 222Rn, which generates on the source surface during alpha-decay process of its parent 226Ra, has been basically investigated. The thinly and uniformly distributed 226Ra-sources were prepared with high deposition yield by the molecular plating technique, in which radium was deposited on a stainless-steel cathode from an isopropanol media by adopting a rotating platinum anode, applied potential of 900 V, and deposition time of 40 min. The ejection efficiency of 222Rn was determined by using the relationship between the 226Ra strength on source and the 222Rn-one transferred on a stainless steel collector in vacuum. It was found that the ejection (or injection) efficiency was greatly influenced on the source preparation methods. The highest ejection efficiency (up to 30%) could be obtained from the electroplated source, whereas the same source could be resulted in the significant decrease of this value (till 2%) after simple ignition treatment. The retention efficiency of 222Rn injected on some collector materials was evaluated to be more than 70% over the tested collectors. From these results, it was concluded that the recoil effects should be most important to interpret the emanation phenomena even in nature.

Alpha Particles↗
PubMed1980

Activation of antibacterial silver coatings on surgical implants by direct current: preliminary studies in rabbits.

Staphylococcus aureus contamination on intramedullary silver pins in the femurs of rabbits was decreased 69% by the application of 9 muA for 1 hour of positive direct current/cm2 (9muAH+DC/cm2). Injection of a solution of silver chloride or silver nitrate into the bone marrow before insertion of the contaminated pins and subsequent application of 12 muAH+DC/cm2 to the stainless steel pins reduced the colony counts 25% and 64%, respectively, and indicated a need for the Ag+ and Cl- ionic state on the pins' surfaces. Stainless steel pins electroplated with silver and charged with 12 muAH+DC/cm2 decreased the bacterial counts by 85%. A 91% inhibition with stainless steel pins electroplated with silver and chlorided indicated that bacteriostasis was possible due to the Ag+/AgCl/Cl- surface effect. Total bacterial inhibition was achieved by 12 muAH+DC/cm2 on stainless steel pins coated with 100 monomolecular layers of silver stearate. The electrical activation of this coating eliminated up to approximately 3,000 S aureau contaminating the intramedullary pins.

Animals↗
PubMed2001

Oxygen-sensing microdialysis probe for in vivo use.

Electrochemical conditions were optimized to allow the metal tube used for the shaft of commercial microdialysis (MD) probes to be coated with gold. In in vitro tests with phosphate-buffered Ringer's solution using double differential pulse amperometry (DDPA), the gold-coated shafts were capable of specifically measuring the reduction of oxygen and the oxidation of ascorbic acid in the presence of high concentrations of potentially interfering endogenous substances. By using fixed-potential amperometry (FPA), the gold-plated shaft also measured oxygen with minimal interference from high concentrations of potentially interfering endogenous substances. Concentric design MD probes were constructed that used a metal shaft (O.D = 0.4 mm), fused silica inlet and outlet tubes, and a 1.5 mm dialyzing membrane (O.D = 0.2 mm). A 0.5-0.7 mm gold collar was electroplated onto the metal shaft approximately 0.5 mm above the dialyzing membrane. The nongold outer surface of the MD probe was coated with an insulating polymer. In vivo tests demonstrated that DDPA was not suitable for use with this gold microdialyzing electrode (GMDE). However, brain oxygen levels were satisfactorily measured using FPA. In urethane-anesthetized rats, the reduction current to oxygen in the striatum was increased by brief (1 min) inhalation of O2 or CO2 and decreased by inhalation of N2. Transient application of noxious stimuli (foot pinch) increased cerebral O2, whereas bilateral carotid artery occlusion and death decreased striatal O2. The responses of the GMDE were indistinguishable from the reduction current simultaneously measured from a conventional carbon fiber electrode implanted adjacent to the gold-plated area of the MD shaft. Basal levels of striatal O(2) were 20 +/- 5 microM (n = 4) for the GMDE and 30 +/- 11 microM (n = 3) for the carbon fiber. The GMDE was robust and could be used for at least three animals. This technique can be used to provide information about the oxygen status of the tissue adjacent to the dialyzing membrane without the need for implantation of an additional electrode.

Animals↗
PubMed2001

Long-term clinical safety and efficacy of NIROYAL vs. NIR intracoronary stent.

Research in vitro and in animal models suggested that gold electroplating of stents can attenuate neointimal hyperplasia and reduce thrombogenicity. The objective of this study was to evaluate the safety and efficacy of the gold-coated NIROYAL stent in the treatment of stenosed coronary arteries and bypass grafts. We retrospectively studied 181 consecutive patients undergoing deployment of NIR (n = 87) or NIROYAL (n = 94) coronary stents in a single tertiary referral center from July 1997 to December 1998. Mean follow-up duration for the NIR and NIROYAL patient groups were 11.6 and 11.4 (range, 3-12) months, respectively. Stent thrombosis rates were 3/87 (3%) in the NIR and 0/94 (0%) in the NIROYAL group (P = 0.07). The need for target lesion revascularization (TLR) in the NIR patient group was 8/87 (9%) compared to 11/94 (12%) in the NIROYAL patient group (P = 0.6). The overall MACE rates for the NIR and NIROYAL patient groups were 24/87 (28%) and 22/94 (23%), respectively (P = 0.5). The present study, hence, implies equivalence between the stainless steel NIR and the gold-plated NIROYAL stent with no significant difference in immediate and long-term clinical performance profiles.

Angioplasty, Balloon, Coronary↗
PubMed1994

Specimen preparation of free-standing, thick-metal, multilayered films in cross section.

A new preparation method permits the production of large-area, electron-transparent, transmission electron microscopy (TEM) specimens in cross section of free-standing, thick, multilayered structures. Such production often has been difficult in the past because of large chemical differences between the component layers in the multilayer. This difference usually results in a large difference in thinning rates between the layers. A unique combination of electroplating, lapping, dimpling, and low-angle ion milling is a successful and reproducible technique for producing high-quality TEM specimens of these complex materials. Procedures and results presented here are for a 304 stainless-steel/copper multilayer having a repeat period of 20 nm and a total thickness of 20 microns.

Copper↗
PubMed1998

Sister chromatid exchange induced by chromium compounds in human lymphocytes.

The objective of this study was to study was to compare chromium (Cr), nickel-chromium (Ni-Cr), and control groups for sister chromatid exchange (SCE) in lymphocytes to obtain an understanding of the mutagenic effect of Cr(VI) in humans. Subjects totaled 91 persons from the 3 groups, including 14 Cr and 34 Ni-Cr electroplating workers and 43 control group members. Results showed that blood and urine Cr concentrations were highest among Cr workers (11.39 microg/l, 14.7 microg/g creatinine), next highest among Ni-Cr workers (5.28 microg/l, 6.2 microg/g creatinine), and lowest among the control group (2.36 microg/l, NA). After adjustment for smoking habits, SCE/cell values were 10.6, 9.4, and 8.3 for Cr workers, Ni-Cr workers, and controls, respectively. A synergetic effect was shown on HFC (high-frequency cells) percentages for Cr workers who also smoked. Odds ratios were 31.78 and 3.66 that Cr and Ni-Cr workers would have higher HFC percentages than the control group, respectively. The authors conclude that SCE in lymphocytes is useful for evaluation of the biological effects of environmental mutagens.

Adult↗
PubMed2006

The development of a multichannel electrode array for retinal prostheses.

The development of a multielectrode array is the key issue for retinal prostheses. We developed a 10 x 10 platinum electrode array that consists of an 8-microm polyimide layer sandwiched between 5-microm polymonochloro-para-xylylene (parylene-C) layers. Each electrode was formed as a 30-microm-high bump by Pt/Au double-layer electroplating. We estimated the charge delivery capability (CDC) of the electrode by measuring the CDCs of two-channel electrode arrays. The dimensions of each electrode of the two-channel array were the same as those of each electrode formed on the 10 x 10 array. The results suggest that for cathodic-first (CF) pulses, 80% of electrodes surpassed our development target of 318 microC/cm2, which corresponds to the charge density of pulses of 500 micros duration and 200 microA amplitude for a 200-microm-diameter planar electrode.

Electrodes, Implanted↗
PubMed1992

In vivo corrosion behavior of gold-plated versus titanium dental retention pins.

Two types of titanium dental retention pins and a gold-plated stainless steel pin were tested for their in vivo corrosion behavior. Six paired samples of titanium and gold-plated pins were placed in box preparations of 12 periodontally involved premolars. Half of the samples were restored with a high copper admixed type amalgam while the rest were restored with a BisGMA-POCl2 bonding resin and a hybrid visible light-cured composite resin. After 3 months in vivo, the teeth were extracted, and the pins were removed and examined with an electron microprobe. The surface of the titanium pins was found to be smooth and without defects. Only traces of Ca and P could be identified from dentin. The gold-plated pins demonstrated cracks and pores, especially at the outer part of the serrations, resulting in disruption of the electroplated film. Traces of Hg, Sn, Cu, S, Zn, Ca, K, Cl, P, and S were detected at the gold-plated pin/amalgam interface, while Cl and P were found at the gold-plated pin/composite resin interface. The in vivo corrosion resistance of the titanium pins was found to be superior to that of the gold-plated stainless steel pins.

Calcium↗