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At least 343 records · Page 19Linked to original sources
PubMed2000

Prediction of toxic substances emission for occupational exposure assessment.

Methods for predicting organic solvents, chromic acid, mineral oil, styrene, and sulphuric acid emissions in painting, metal degreasing, wood preservation, chromium electroplating, turning, grinding, making glass fortified polyester laminates and lead batteries charging, injection moulding of polystyrene plastics, and making polyurethane foam processes are described. Experimentally introduced equations are based on the essential parameters of these processes. Knowing the emission and the total flow rate of ventilation, it is possible to calculate toxic agent concentration, which is the basis of occupational exposure assessment.

Air Pollutants, Occupational↗
PubMed1986

Comparative cytotoxicity of four nickel compounds to canine and rodent alveolar macrophages in vitro.

Nickel subsulfide (Ni3S2), nickel sulfate (NiSO4), nickel chloride (NiCl2), and nickel oxide (NiO), are four compounds encountered by workers in the nickel-refining and electroplating industries. These compounds were tested for their relative toxicity to beagle dog and F344/Crl rat alveolar macrophages in vitro. Dog alveolar macrophages were at least 10 times more sensitive to the effects of each of the 4 nickel compounds than were rat alveolar macrophages. Toxicity ranking of the four nickel compounds to macrophages from both species was Ni3S2 greater than NiCl2 approximately NiSO4 greater than NiO.

Animals↗
PubMed2004

Rapid cyanide detection using the Cyantesmo kit.

BACKGROUND: Sources of cyanide exposure are many, including combustion of plastic and vinyl, such as in a house fire, laboratory or industrial exposures including exposure in the electroplating industry both of printed circuit boards and in jewelry work. Rapid and definitive diagnosis of cyanide poisoning is unavailable in the emergency department setting. It is desirable to make a definitive diagnosis in order to prevent potential complications of empiric treatment of presumptive cyanide poisoning from the cyanide antidote kit currently approved by the US Food and Drug Administration (FDA). We investigated a technique to detect cyanide currently utilized by water treatment facilities to determine if it can be applied to rapidly detect concentrations of cyanide in the clinically important range. METHODS: Varying standardized dilutions of KCN ranging from 0.25 microg/mL to 30 microg/mL were acidified with a drop of sulphuric acid in a closed system under a ventilation hood. Cyantesmo test strips were placed into the test tubes above the fluid level where liberated HCN gas interacted with the test strip to effect a color change. Color changes were compared to negative controls and to each other. RESULTS: The test strips demonstrated an incrementally increasing deep blue color change over a progressively longer portion of the test strip in less than 5 minutes for each concentration of KCN including 1, 3, 10, and 30 microg/mL. The concentrations of 0.25, 0.5, and 0.75 required more than 2 hours to begin demonstration of any color change. CONCLUSION: The Cyantesmo test strips accurately and rapidly detected, in a semi-quantifiable manner, concentrations of CN greater than 1 microg/mL contained in each test sample. Future work to validate this test in blood and in clinical specimens is planned.

Cyanides↗
PubMed2004

Contribution of cell outer membrane and inner membrane to Cu2+ adsorption by cell envelope of Pseudomonas putida 5-x.

The role of outer and inner membrane in the Cu2+ adsorption process by gram-negative bacterium Pseudomonas putida 5-x, which was isolated from local electroplating effluent with high Cu2+ accumulating capability, was studied. The results indicate that both the outer and inner membrane exhibited high Cu2+ adsorption capacity. Outer and inner membrane contributed about 30-35% and 20-25% parts of adsorption capacity in Cu2+ adsorption by cell envelope of Pseudomonas putida 5-x, respectively. The total contribution of outer and inner membrane to Cu2+ adsorption by cell envelope was much greater than that of peptidoglycan layer. The relatively high phospholipid content in the outer membrane might result in its greater heavy metal ions adsorption capacity. The Cu2+ binding process by the outer and inner membrane of Pseudomonas putida 5-x is the adsorption processes and can be described with Freundlich isotherms.

Adsorption↗
PubMed1992

A survey of chronic bronchitis among brassware workers.

A stratified random sample of 580 workers aged between 18 and 50 years representing each sub-occupation in the brassware industry was studied for the prevalence of chronic bronchitis in relation to occupational and environmental factors. The findings were compared with those obtained in a reference group (N = 131) belonging to similar socio-economic status and unexposed to a dusty environment. Although the exposed group showed higher prevalence of chronic bronchitis in comparison to that observed in the controls (10.5 vs 5.3%), the difference was not significant at the 5% level. It was observed that the workers engaged in non-dusty occupations such as brass sheet cutting and engraving showed the lowest prevalence of the disease (5.0%) while those engaged in the dusty occupations viz., casting, soldering, electroplating and polishing showed the highest prevalence (12.0%). The smoking adjusted odds ratios calculated in various sub-occupations showed the highest risk of developing chronic bronchitis among the polishers (2.74). Though the risk in other occupational sub-groups was double, it did not attain a level of significance. The smoking adjusted odds ratios in relation to length of exposure showed that the risk was significantly higher among the workers exposed for over 10 years compared to those who worked for less than 10 years in the grinding, soldering and brass ingot making operations. The study thus showed a dose-response relationship between length of exposure and chronic bronchitis while effect of age on the disease was not discernible probably due to the small number of cases and the young age of the study group. The concentration of various metals in the air samples drawn from the work environment where main processes were in operation, was low compared to the prescribed level by ACGIH.

Adolescent↗
PubMed1998

Nasal septal ulceration and perforation in jiggers.

The paper describes two cases of occupational ill-health in individuals working as jiggers in the chromium electroplating industry. Much has been written about the effects of chromic acid on the platers who may work directly over the plating baths, but a literature search failed to identify any reports of ill-health in those who work alongside platers preparing the items to be placed into the baths. One case of nasal ulceration and one of nasal septal perforation are described. Reference is made to the role of the 'responsible person' in health surveillance for such workers to allow early identification of occupationally acquired ill-health and prevention of further cases.

Adolescent↗
PubMed2004

The treatment of cyanide poisoning.

Cyanide has gained historical notoriety as a poison used with intent to cause fatality. Its occurrence in industry is confined to a small number of uses in a relatively narrow range of industries, including the manufacture of Perspex and nylon and in electroplating. With proper controls in these settings, episodes of poisoning are extremely rare. However, because of the potential for a fatal outcome, procedures for the treatment of acute poisoning are essential. Antidotes include methaemoglobin generators, direct binding agents and sulphur donors, but there is a lack of international consensus about the treatment of choice. This article reviews the mechanisms and treatment of cyanide intoxication and emphasizes the importance of having agreed local procedures for the emergency treatment of poisoning.

Antidotes↗
PubMed1983

Levels of 234U, 238U and 230Th in excreta of uranium mill crushermen.

Pacific Northwest Laboratory conducted a research program to measure uranium and thorium levels in excreta of uranium mill crushermen who are routinely exposed to airborne uranium ore dust. The purpose of this work was to determine whether 230Th was preferentially retained in the body over either 234U or 238U. Urine and fecal samples were obtained from 14 active crushermen with long histories of exposure to uranium ore dust, plus four retired crushermen and three control individuals for comparison. Radiochemical procedures were used to separate out the uranium and thorium fractions which were then electroplated on stainless steel discs and assayed by alpha spectrometry. Significantly greater activity levels of 234U and 238U were measured in both urine and fecal samples obtained from uranium mill crushermen, indicating that uranium in the inhaled ore dust was cleared from the body with a shorter biological half-time than the daughter product 230Th. The measurements also indicated that uranium and thorium separate in vivo and have distinctly different metabolic pathways and transfer rates in the body.

Alpha Particles↗
PubMed1993

Factors that affect alpha particle detection in continuous air monitor applications.

An experimental study was conducted to characterize the full-width half-maximum values, peak shapes, and peak shifts of the energy spectra from alpha emitters in the forms of particulate matter on sampling filters and electro-deposited plated sources. Monodisperse 1.0-microns anhydrous uranium acetate aerosol particles were collected on seven types of sampling filters. Full-width half-maximum values at atmospheric pressure varied from 373 keV for a 3-microns pore size Fluoropore filter to 584 keV for a glass fiber filter. Monodisperse uranium acetate aerosols from 1.2-8.1 microns were collected on Millipore 1.2-microns pore size membrane filters to examine the self-absorption effect. Under vacuum, the corresponding full-width half-maximum values ranged from 241-1,011 keV. Successively heavier mass loadings of monodisperse 1.8-microns uranium acetate particles from 13.7-127 micrograms cm-2 caused the values to increase from 420 to 580 keV. With an electroplated 23.9-mm-diameter 239Pu source and a 25.4-mm detector, the distance between source and detector was incrementally increased from 3.2 to 6.4 mm--a range of distances that is typical of those found in alpha continuous air monitors. At atmospheric pressure, the values increased from 280 to 330 keV and the detector efficiency decreased from 30.5% to 20.9%. Tests with various sizes of sources and detectors suggest that a continuous air monitor should be designed so that the two are of approximately equal size.

Air Pollutants, Occupational↗
PubMed2001

Principles of gross alpha and beta radioactivity detection in water.

A simultaneous detection of gross alpha and beta radioactivity was studied using gas proportional counting. This measurement is a part of a method mandated by US Environmental Protection Agency to screen for alpha and beta radioactivity in drinking water. Responses of a gas proportional detector to alpha and beta particles from several radionuclides were determined in drop and electroplated geometries. It is shown that, while the alpha radioactivity can be measured accurately in the presence of beta radioactivity, the opposite is not typically true due to alpha-to-beta crosstalk. The crosstalk, originating from the emission of conversion and Auger electrons as well as x rays, is shown to be dependent primarily on the particular alpha-decay scheme while the dependence on alpha energy is small but negligible. It was measured at 28-35% for 241Am, 22-24% for 230Th, and 4.9-6.5% for 239Pu. For 210Po, the crosstalk of 1.2-1.6% was observed mostly due to energy retardation. A method of reducing the crosstalk to a <3% level is proposed by absorbing the atomic electrons in a 6.2 mg cm(-2) Al absorber, at the same time decreasing the beta efficiency by 16-31%.

Alpha Particles↗
PubMed1997

Evaluation of cyanide exposure and its effect on thyroid function of workers in a cable industry.

A thyroid-hormone evaluation of workers dealing with cyanide compounds in an electroplating process of a cable industry was carried out. Serum thiocyanate (SCN) levels of 35 nonsmoking copper-ply employees were assayed by a ferric-chloride color test. The mean SCN concentration of these employees was 316 +/- 15 mumol/L, which was significantly (P < 0.01) higher than that of control subjects (90.8 +/- 9.02 mumol/L). Serum thyroxine (T4), triiodothyronine (T3), and thyroid-stimulating hormone (TSH) concentrations of exposed workers were compared with those of 35 control subjects. Cyanide exposure resulted in a decrease in T4 and T3 concentrations (P < 0.05) and an increase in TSH concentration (P < 0.05), compared with the control subjects. The serum T4 level was found to be negatively correlated (r = -0.363, P < 0.05), whereas the TSH level was positively correlated (r = 0.354, P < 0.05), with SCN concentration in the exposed group. The study suggests that occupational cyanide exposure in the industry impairs thyroid function.

Adult↗
PubMed2004

Role of various extractants in removing group-IIB elements of soils incubated with EDTA.

This paper presents the results of an experimental investigation undertaken to evaluate different extractant solutions viz. HCl, Mg(NO3)2, and DTPA with the range of concentration from 0.001 to 0.1N after incubation with group-IIB metals (Zn, Cd, and Hg) and EDTA to understand the capability to remove Zn, Cd, and Hg from soils. Two noncontaminated soils, one acidic (GHL) and the other alkaline (KAP), in reaction were taken from an agricultural field of West Bengal, India for this investigation. Experiments were conducted on these two soils spiked with ZnII, CdII, and HgII in concentrations of 612, 321, and 215 mg/kg for soil GHL and 778, 298, and 157 mg/kg for soil KAP, respectively, which simulate typical electroplating waste contamination. The removal of Zn, Cd, and Hg in soil GHL within the range of HCl concentrations was 8.2-16.5, 12.2-19.1, and 4.3-6.9 whereas these were 6.5-7.6, 8.5-14.1, and 3.2-5.2 in soil KAP. The removal of Zn, Cd, and Hg in soil GHL within the range of Mg(NO3)2 concentrations were 12.2-28.5, 19.1-24.6, and 18.2-19.1 whereas these were 9.1-12.1, 8.3-12.1, and 10.6-48.1 in soil KAP. For DTPA extractant, the percent removal of metal was found to be significantly higher than the other two extractants, which corroborates that DTPA is a better extractant for soil cleaning.

Cadmium↗
PubMed2006

Electron transport in self-assembled polymer molecular junctions.

A molecular junction of a poly(p-phenyleneethynylene)s derivative with thioacetate end groups (TA-PPE) was fabricated by self-assembling. Nanogap electrodes made by electroplating technique was used to couple thiol end groups of TA-PPE molecules. Room temperature current-voltage characteristics of the molecular junction exhibited highly periodic, repeatable, and identical stepwise features. First-principles calculations suggest that one possibility for the equidistant step is due to the opening of different conducting channels that corresponds to the unoccupied molecular orbitals of the polymer in the junction. It is interesting to see that an 18 nm long polymer is of quantized electronic structures and behaves like a quantum transport device.

Journal Article↗
PubMed1994

A three-dimensional microelectrode array for chronic neural recording.

This paper describes a 3-D microelectrode array for the chronic recording of single-unit activity in the central nervous system. The array is formed by a microassembly of planar silicon multishank microprobes, which are precisely positioned in a micromachined platform that resides on the surface of the cortex. Interconnects between the probes and the platform are formed using electroplated nickel lead transfers, implemented using automated computer control. All dimensions are controlled to +/- 1 micron and sank/probe separations as small as 100 microns are possible. Four-probe 16-shank prototype arrays have been tested chronically in guinea pig cortex. After three months in vivo, no significant tissue reaction has been observed surrounding these structures when they remain free to move with the brain, with normal appearing tissue between shanks spaced at 150 microns to 200 microns intervals. The array structure is compatible with the use of signal processing circuitry both on the probes and on the platform. A platform-based signal processing system has been designed to interface with several active probes, providing direct analog access to the recording sites, performing on-chip analog-to-digital conversion of neural activity, and providing simple binary-output recognition of single-unit spike events using a user-input threshold voltage.

Animals↗
PubMed1999

A modular micromachined high-density connector system for biomedical applications.

This paper presents a high-density, modular, low-profile, small, and removable connector system developed using micromachining technologies for biomedical applications. This system consists of a silicon or polyimide electrode with one end in contact with the biological tissue and its back-end supported in a titanium base (12.5 mm in diameter and 2.5 mm in height) that is fixed on the test subject. An external glass substrate (6 x 6 x 0.75 mm3), which supports a flexible polyimide diaphragm and CMOS buffers, is attached to the titanium base whenever electrical contact is required. The polyimide flexible diaphragm contains high-density gold electroplated pads (32 pads, each having an area of 100 x 100 micron 2 and separated by 150 microns) which match similar pads on the electrode back-end. When vacuum is applied between the two, the polyimide diaphragm deflects and the corresponding gold pads touch, therefore, establishing electrical connection. In vitro electrical tests in saline solution have been performed on a 32-site connector system demonstrating < 5 omega contact resistance, which remained stable after 70 connections, and -55 dB crosstalk at 1 kHz between adjacent channels. In vivo experiments have also confirmed the establishment of multiple contacts and have produced simultaneous biopotential recordings from the guinea pig occipital cortex.

Animals↗
PubMed2004

Mobile patient monitoring based on impedance-loaded SAW-sensors.

A remotely requestable, passive, short-range sensor network for measuring small voltages is presented. The sensor system is able to simultaneously monitor six small voltages in millivolt-range, and it can be used for Holter-electrocardiogram (ECG) and other biopotential monitoring, or in industrial applications. The sensors are based on a surface acoustic wave (SAW) delay line with voltage-dependent, impedance loading on a reflector interdigital transducer (IDT). The load circuit impedance is varied by the capacitance of the voltage-controlled varactor. High resolution is achieved by developing a MOS-capacitor with a thin oxide, low flat-band voltage, and zero-voltage capacitance in the space-charge region, as well as a high-Q-microcoil by thick metal electroplating. Simultaneous monitoring of multiple potentials is realized by time-division-multiplexing of different sensor signals.

Acoustics↗
PubMed2006

Development of a high-frequency (> 50 mhz) copolymer annular-array, ultrasound transducer.

The development of a high frequency (> 50 MHz) annular array ultrasonic transducer is presented. The array was constructed by bonding a 9 microm P(VDF-TrFE) film to a two-sided polyimide flexible circuit with annuli electrodes on the top layer. Each annulus was separated by a 30 microm kerf and had several electroplated microvias that connected to electrode traces on the bottom side of the flex circuit. In order to improve device sensitivity, each element was electrically matched to an impedance magnitude of 50 omega and 0 degrees phase at resonance using a serial inductor and high impedance coaxial cable. The array's performance was evaluated by measuring the electrical impedance, pulse echo response, and cross talk between elements. The average round trip insertion loss was -33.5 dB after compensating for diffractive and attenuative losses. The measured average center frequency and bandwidth for an element was 55 MHz and 47%, respectively. The measured cross talk between adjacent elements remained below -29 dB at the center frequency in water. A vertical wire phantom was imaged using a single focus transmit beamformer and dynamic focusing receive beamformer. This image showed a significant improvement in lateral resolution over a range of 9 mm after the dynamic focusing receive algorithm was applied. These results correlated well with predictions from a Field II simulation. After beamforming, the minimum lateral resolution achieved by the array (-6 dB) was 108 microm at the focus.

Journal Article↗
PubMed1986

Acute poisoning with gold cyanide.

A case of deliberate ingestion of an electroplating solution containing gold cyanide is described. Despite the use of an antidote, and supportive treatment for cyanide poisoning, the patient died after 13 hours. Sublethal cyanide and high red blood cell gold levels suggest acute gold toxicity as the most likely cause of death. Evidence for this is discussed and recommendations are made for the treatment of cyanide poisoning.

Acute Disease↗