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 361 records · Page 20Linked to original sources
PubMed1988

A new low threshold platinized epicardial pacing electrode: comparative evaluation in immature canines.

A prospective comparison of pacing and sensing capabilities between the conventional Medtronic Model 4951 platinum-iridium epicardial pacing electrode and a new modified "platinized" version of the same electrode was performed in immature canines to determine if the new electrode design improves pacing in the immature myocardium. The conventional electrode was modified by electroplating platinum black particles onto the surface to increase the effective or true microscopic surface area, yet essentially maintain the same overall geometric electrode size. Both epicardial electrodes were inserted into the right ventricular myocardium with the lead pad sutured to the epicardium, and externalized to the scruff in five puppies (age 3 months). An additional left ventricular lead was implanted to permit chronic pacing following epicardially-induced atrioventricular block. Acute and chronic sensing and pacing capabilities of each externalized electrode were performed at implant and weekly up to 4 months. Histologic examination of each electrode implant site was performed at the end of the study period. At implant, both electrodes exhibited comparable values for sensed R waves, lead impedances, and pacing thresholds. During the study, the platinized electrode exhibited lower pacing thresholds. Analysis of all postimplant data demonstrated this threshold difference to be significantly lower (P less than .01) for the platinized version. Lead impedance and sensing capabilities remained comparable between the two designs. Histologic study demonstrated less fibrotic infiltration at the platinized electrode site. This preliminary evaluation indicates that for the duration of the postimplant study period, the platinized epicardial electrode design was associated with significantly lower thresholds and less fibrosis as a function of time compared to the conventional smooth electrode surface design. The new platinized electrode limits exit block in the developing immature myocardium and permits safe pacing at lower pulse widths and voltages to increase battery life.

Animals↗
PubMed1997

Hand dermatitis and allergic patch test reactions caused by nickel in electroplaters.

A worksite survey was conducted in all 38 Finnish electroplating plants. All workers (n = 163) who worked with nickel plating (bath workers, hangers and solution makers) were interviewed with a questionnaire about symptoms of nickel dermatitis, hand dermatitis, and about protective measures, atopy, etc. Patch testing with nickel sulfate was done with the TRUE TestTM method. All the workers, 94 men and 69 women, answered the questionnaire. The mean age of women was 41.1 years, and of men 43.1 years, respectively. Men had longer occupational exposure to nickel (14 years) than women (10 years). Most workers used protective gloves. 35% of women and 30% of men reported present or past hand dermatosis. 19% reported a history of atopic dermatitis. 15% of women (n = 8) and 4% (n = 2) of men had an allergic patch test reaction to nickel sulfate. 70% of those with an allergic patch test reaction to nickel reported past or present hand eczema. The prevalence of nickel allergy among the electroplaters was similar to that of patients in patch test clinics in Finland. An allergic patch test reaction to nickel sulfate does not necessarily oblige an electroplater to change jobs.

Adult↗
PubMed1999

Micromachining in plastics using X-ray lithography for the fabrication of microelectrophoresis devices.

Micromachining was performed in polymethylmethacrylate (PMMA) using X-ray lithography for the fabrication of miniaturized devices (microchips) for potential applications in chemical and genetic analyses. The devices were fabricated using two different techniques: transfer mask technology and a Kapton mask. For both processes, the channel topography was transferred (1:1) to the appropriate substrate via the use of an optical mask. In the case of the transfer mask technique, the PMMA substrate was coated with a positive photoresist and a thin Au/Cr plating base. Following UV exposure, the resist was developed and a thick overlayer (approximately 3 microns) of Au electroplated onto the PMMA substrate only where the resist was removed, which acted as an absorber of the X-rays. In the other technique, a Kapton film was used as the X-ray mask. In this case, the Kapton film was UV exposed using the optical mask to define the channel topography and following development of the resist, a thick Au overlayer (8 microns) was electrodeposited onto the Kapton sheet. The PMMA wafer during X-ray exposure was situated directly underneath the Kapton mask. In both cases, the PMMA wafer was exposed to soft X-rays and developed to remove the exposed PMMA. The resulting channels were found to be 20 microns in width (determined by optical mask) with channel depths of approximately 50 microns (determined by x-ray exposure time). In order to demonstrate the utility of this micromachining process, several components were fabricated in PMMA including capillary/chip connectors, injectors for fixed-volume sample introduction, separation channels for electrophoresis and integrated fiber optic fluorescence detectors. These components could be integrated into a single device to assemble a system appropriate for the rapid analysis of various targets.

Electrophoresis, Capillary↗
PubMed2004

Development of high quantum efficiency, flat panel, thick detectors for megavoltage x-ray imaging: a novel direct-conversion design and its feasibility.

Most electronic portal imaging devices (EPIDs) developed to date, including recently developed flat panel systems, have low x-ray absorption, i.e., low quantum efficiency (QE) of 2%-4% as compared to the theoretical limit of 100%. A significant increase of QE is desirable for applications such as a megavoltage cone-beam computed tomography (MVCT) and megavoltage fluoroscopy. However, the spatial resolution of an imaging system usually decreases significantly with an increase of QE. The key to the success in the design of a high QE detector is therefore to maintain the spatial resolution. Recently, we demonstrated theoretically that it is possible to design a portal imaging detector with both high QE and high resolution [see Pang and Rowlands, Med. Phys. 29, 2274 (2002)]. In this paper, we introduce such a novel design consisting of a large number of microstructured plates (made by, e.g., photolithographic patterning of evaporated or electroplated layers) packed together and aligned with the incident x rays. On each plate, microstrip charge collectors are focused toward the x-ray source to collect charges generated in the ionization medium (e.g., air or gas) surrounded by high-density materials that act as x-ray converters. The collected charges represent the x-ray image and can be read out by various means, including a two-dimensional (2-D) active readout matrix. The QE, spatial resolution, and sensitivity of the detector have been calculated. It has been shown that the new design will have a QE of more than an order of magnitude higher and a spatial resolution equivalent to that of flat panel systems currently used for portal imaging. The new design is also quantum noise limited down to very low doses (approximately 1-2 radiation pulses of the linear accelerator).

Equipment Design↗
PubMed1994

Measuring the human head-related transfer functions: a novel method for the construction and calibration of a miniature "in-ear" recording system.

A method for the construction of a small "in-ear" system for recording the human-free field-to-eardrum and headphone-to-eardrum transfer functions is described. Customized in-ear inserts were obtained by a simple ear printing and electroplating method, resulting in a thin (< 0.25 mm) outer shell that minimized obstruction of the entrance at the ear canal. The insert can be used to position a microphone probe tube deep within the auditory canal. The effects of this recording system on the sound field in the ear canal were calibrated using a model head equipped with a second internal microphone close to the eardrum. Transfer functions were recorded for 343 different stimulus locations in free space and for a headphone sound source. For the free-field stimuli the presence of the recording system resulted in a small attenuation with maximum effects around 3.5 and 12.5 kHz (-1.5 and -2.0 dB, respectively). Passing the data through an auditory filter model reduced the averaged attenuation to less than -1.4 dB. Phase was undistorted up to 2.5 kHz. These results suggests that the perturbations produced by the insert are unlikely to be perceptually relevant.

Acoustic Stimulation↗
PubMed1975

Chronic cyanide exposure: a clinical, radioisotope, and laboratory study.

The effect of chronic cyanide exposure in the electroplating sections of three factories employing 36 workers was studied and compared with a control group. The concentration of cyanides to which the workers were exposed was measured. The regression line showing the relationship between thiocyanates in urine and the concentration of cyanides in the air was plotted. Increased percentages of haemoglobin and lymphocyte count were present in all exposed workers, in addition to punctate basophilia in 28 workers. Cyanmethaemoglobin was found to be characteristic. Apart from other complaints, two men with psychosis similar to one case reported in therapeutic thiocyanate intoxication were found. Twenty of the workers had thyroid enlargements to a variable degree and consistency, in two of whom it resembled lymphadenoid goitre. Thyroid 131I uptakes at 4 and 24 hours were significantly higher than in the controls, while 131PBI was unchanged. The reason for this iodine deficiency-like action is discussed.

Adult↗
PubMed1983

Technique for making hollow central airway casts.

We have developed a method for producing rigid hollow casts of the central airways. Woods metal (melting point 70 degrees C) was poured into the airways at the trachea of an excised canine lung air-dried at a transpulmonary pressure of 30 cmH2O. The tissue was dissolved and removed, and the resulting negative cast was carefully trimmed leaving only airways with a diameter of 2 mm or greater. The cast was then electroplated with copper that provided a rigid jacket encasing the Woods metal. Heating this structure to 100 degrees C liquefied the Woods metal allowing the majority of it to flow out. Residual amounts were readily removed by a high-pressure steam hose attached to the trachea. Comparisons were made between airway diameters from in vivo radiographic bronchograms (DB) and direct measurements of the resulting trimmed Woods metal cast (DC). Linear regression analysis of these data indicated a high degree of correlation (DC = 0.98 DB + 0.03, r = 0.99). We concluded that this technique produces positive casts which provide a good representative model of the central airways.

Animals↗
PubMed2006

Report: transboundary hazardous waste management. part II: performance auditing of treatment facilities in importing countries.

Before implementing the self-monitoring model programme of the Basel Convention in the Asia, Taiwan has conducted a comprehensive 4-year follow-up project to visit the governmental authorities and waste-disposal facilities in the countries that import waste from Taiwan. A total of nine treatment facilities, six of which are reported in this paper, and the five countries where the plants are located were visited in 2001-2002. France, Belgium and Finland primarily handled polychlorinated biphenyl capacitors, steel mill dust and metal waste. The United States accepted metal sludge, mainly electroplating sludge, from Taiwan. Waste printed circuit boards, waste wires and cables, and a mixture of waste metals and electronics were the major items exported to China. Relatively speaking, most treatment plants for hazardous waste paid close attention to environmental management, such as pollution control and monitoring, site zoning, system management regarding occupational safety and hygiene, data management, permits application, and image promotion. Under the tight restrictions formulated by the central environment agency, waste treatment plants in China managed the environmental issues seriously. For example, one of the treatment plants had ISO 14001 certification. It is believed that with continuous implementation of regulations, more improvement is foreseeable. Meanwhile, Taiwan and China should also continuously enhance their collaboration regarding the transboundary management of hazardous waste.

Commerce↗
PubMed1991

Non-Hodgkin's lymphoma and occupation in Denmark.

An analysis was made of the occurrence in Denmark of non-Hodgkin's lymphoma among men and women by socioeconomic group and detailed occupation, using a linkage between cancer registry data on incidence (1970-1980) and census data on industry and occupation (1970). No socioeconomic gradient in the risk for non-Hodgkin's lymphoma was found. Significantly increased relative risks were found in a number of detailed occupational groups including female physicians, female family workers in retail trade and transport; and male fitters, and gold, silver, and electroplate workers in metal industry. Also male cowmen experienced a significantly increased risk, whereas the risk was not increased for farming in general. Tabulations of clusters of detailed occupational groups suggested that groups with potential exposure to infections and chemical agents may experience an increased risk for NHL.

Adult↗
PubMed2002

Surface characterization techniques for determining the root-mean-square roughness and power spectral densities of optical components.

Surface topography and light scattering were measured on 15 samples ranging from those having smooth surfaces to others with ground surfaces. The measurement techniques included an atomic force microscope, mechanical and optical profilers, confocal laser scanning microscope, angle-resolved scattering, and total scattering. The samples included polished and ground fused silica, silicon carbide, sapphire, electroplated gold, and diamond-turned brass. The measurement instruments and techniques had different surface spatial wavelength band limits, so the measured roughnesses were not directly comparable. Two-dimensional power spectral density (PSD) functions were calculated from the digitized measurement data, and we obtained rms roughnesses by integrating areas under the PSD curves between fixed upper and lower band limits. In this way, roughnesses measured with different instruments and techniques could be directly compared. Although smaller differences between measurement techniques remained in the calculated roughnesses, these could be explained mostly by surface topographical features such as isolated particles that affected the instruments in different ways.

Journal Article↗
PubMed2004

Fabrication and characterization of a three-dimensional feed-horn infrared antenna for an infrared detector.

A three-dimensional feed-horn antenna for the 10-microm-wavelength infrared region has been suggested, characterized, and fabricated. It is applied to an infrared detector for efficient collection of infrared radiation and to reduce background noise. The optimum size of the horn antenna was designed for maximum antenna directivity. The three-dimensional feed-horn antenna mold was fabricated by rotating and tilting illumination, whereas the antenna plate was acquired through electroplating. Antenna characteristics were measured by coupling of the antenna with a microbolometer. Measurement results show that the directivity of the antenna is 16.1 dB and the background noise is reduced by a factor of approximately 2 compared with an open-structure infrared detector.

Journal Article↗
PubMed2004

Refractive microlens array for wave-front analysis in the medium to hard x-ray range.

We report an alternative approach to x-ray wave-front analysis that uses a refractive microlens array as a Shack-Hartmann sensor. The sensor was manufactured by self-assembly and electroplating techniques and is suitable for high-resolution wave-front analysis of medium to hard x rays. We demonstrate its effectiveness at an x-ray energy of 3 keV for analysis of x-ray wave-front perturbations caused by microscopic objects. The sensor has potential advantages over other methods for x-ray phase imaging and will also be useful for the characterization of x-ray beams and optics.

Journal Article↗
PubMed2006

Contribution of cell-surface components to Cu2+ adsorption by Pseudomonas putida 5-x.

The contribution of various cell-surface components to Cu2+ adsorption by a Gram-negative bacterium, Pseudomonas putida 5-x, that was isolated from local electroplating effluent with a high capability to accumulate heavy metal ions was studied. The cell superficial layer had a negative effect on Cu2+ adsorption of the bacterial cells. Cu2+ adsorption capacity of the separated cell envelopes was fivefold more than that of the intact cells, owing to the liberation of more and more binding sites during the separation process. Some main components in the cell envelope, such as the peptidoglycan (PEG) layer, outer membrane, and inner membrane, provide the capability for Cu2+ adsorption. The content of the components in the cell envelope is in the order inner membrane > outer membrane > PEG layer, and their Cu2+ adsorption capacity was in the order PEG layer > outer membrane > inner membrane. The total contribution of the separated PEG layer material to Cu2+ adsorption by the cell envelope was no more than 15%, and the outer membrane and inner membrane contributed about 30-35% and 25-30%, respectively. The relatively high phospholipid content in the outer membrane may be the major reason for the higher adsorption capacity of the outer membrane to Cu2+ and, hence, such a high Cu2+ adsorption capacity of P. putida 5-x cell envelope.

Adsorption↗
PubMed2000

Fabrication of an electrode-viologen-hydrogenase heterogeneous system and the electrochemical hydrogen evolution.

An indium tin oxide (ITO) electrode was chemically modified by one layer of viologen (VIO) derivative, which possessed a persistent and reproducible electrochemical response. A monolayer of a thermal stable hydrogenase from Thiocapsa roseopersicina was stabilized on a synthesized poly-L-lysine subphase surface and transferred onto the electrode for fabrication of an ITO-VIO-hydrogenase heterogeneous system. Electrochemical properties of both the ITO-VIO monolayer and the heterogeneous ITO-VIO-hydrogenase system have been investigated. Hydrogen evolution could be measured by potentiostating the VIO-hydrogenase-covered ITO electrode to "electroplate" [(VIO+)n]surf, and a large increase in hydrogen evolution was observed when using an electrolyte solution containing sodium dithionite. We discuss the possible electron transfer process.

Electrochemistry↗
PubMed1978

Surface characteristics of resin-coated composite restorations.

Twenty-four maxillary anterior composite restorations from a clinical study of resin coating were examined at the time of baseline evaluation and at 23 months; electroplated positive replicas, impression negative replicas, and SEMs were used for evaluation. Coated restorations had smooth surfaces after 23 months, in comparison with rough surfaces of uncoated restorations. Defects in some of the resin coatings were found at the time of baseline evaluation; these included isolated areas of the composite or etched enamel that were not covered by the resin. Later examinations showed cracking of part of the edges of resin coating, development of bare areas, thinning of the coating edges, or generalized loss of the protective coating. The defects seen immediately after placement of the coatings were probably caused by errors in technique that include: application of the resin in a layer that was too thin; surface contaminants in the area of application; moisture on the surface of the composite or enamel; and areas of inadequate enamel etching were adjacent to the cavosurface margin of the composite. The appearance of bare spots or total loss or thinning of the resin coating edges during the later examinations is caused by wearing or abrading of the resin coatings from natural or mechanical causes. This seems to be a function of the initial coating thickness and its location on the tooth.

Acid Etching, Dental↗
PubMed1981

Surface mechanical properties of stone, resin, and metal dies.

Two improved stone die materials (Duroc and Silky Rock) used with water and with a hardener, one resin die material with dispersed metal powder (Die-Met), and copper and silver electroplated metal die materials were evaluated for surface mechanical properties. The improved stone dies had the highest surface roughness, intermediate surface hardness and the highest loss of material in two-body abrasion. The use of a hardener decreased the surface roughness, but did not improve abrasion resistance. The improved stone dies, with or without hardener, showed brittle failure in single-pass sliding at low normal loads. The resin dies had the lowest hardness. The unfilled resin die had low surface roughness and was similar to metal dies. The resin-metal die had a surface roughness similar to the improved stone dies. The presence of dispersed metal powder in the resin did not increase the hardness. Both resin die materials had intermediate values of material loss in two-body abrasion and showing tensile cracking and loss had intermediate values of material loss in two-body abrasion and showed tensile cracking and loss of material on single-pass sliding at medium normal loads. The metal dies had the highest hardness and the least surface roughness. They also had the lowest material loss in two-body abrasion. The metal dies showed ductile behavior in single-pass sliding.

Calcium Sulfate↗
PubMed2001

Coated-wire silver ion-selective electrode based on silver complex of cyclam.

A coated-wire ion-selective electrode (ISE) based on cyclam (1,4,8,11-tetraazacyclotetradecane) as a neutral carrier in a polyvinyl chloride (PVC) matrix was fabricated for the determination of Ag(I) ions. The coated-wire ISE exhibited a linear Nernstian response over the range 1 x 10(-1) to 1 x 10(-7) M with a slope of 59 +/- 2 mV per decade change and a detection limit of 5 x 10(-8) M. The ISE shows a greater preference for Ag over other cations with good precision. The electrode was selective towards Ag(I) ions in the presence of 13 different metal ions tested. The selectivity coefficients (K(ij)) were determined for Na(I), K(I), Mg(II), Ca(II), Ba(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Hg(II). The selectivity coefficients of these cations are in the range of 10(-4) to 10(-2). This ISE was used for the determination of free silver and total silver in electroplating bath solutions, additives and brighteners.

Journal Article↗
PubMed2004

Synthesis of a new oxime and its application to the construction of a highly selective and sensitive Co(II) PVC-based membrane sensor.

A cobalt(II) ion-selective membrane sensor has been fabricated from a poly vinyl chloride (PVC) matrix membrane containing a new oxime compound (oxime of 1-(2-oxocyclohexyl)-1,2-cyclohexanediol, OXCCD) as a neutral carrier, sodium tetraphenyl borate (NaTPB) as an anionic excluder and o-nitrophenyloctylether (o-NPOE) as a plasticizing solvent mediator. The membrane sensor exhibits a linear potential response in the concentration range of 1.0 x 10(-1) - 1.0 x 10(-6) M of Co2+. The electrode displays a Nernstian slope of 29.8 mV decade(-1) in the pH range of 3.5 - 8.0. The sensor also exhibits a fast response time of < 25 s. The detection limit of the proposed sensor is 9.0 x 10(-7) M (approximately 40 ng/ml), and it can be used over a period of two months. The selectivity of the sensor with respect to other cations (alkali, alkaline earth, transition and heavy metal ions) is excellent. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of Co2+ with EDTA and for the direct determination of Co(II) in wastewater of the electroplating industry.

Journal Article↗