Search Results
Results 451 - 500 of 628
< 3 4 5 6 7 8 9 10 11 12 13 >
do Nascimento P C - - 1999
A method for the polarographic determination of cyanide as contaminant in pralidoxime mesylate (PM) formulations was developed. The volatile cyanide formed in the formulations was stabilized as tetracyanonickelate (TCN) anion complex after reaction with ammoniacal Ni(II) solution. The stable TCN anion complex (K(stb)=10(31)) was determined by anodic stripping voltammetry at ...
Ansheng L - - 1999
The hyphal responses of an A. fumigatus isolate to a trizole derivative-fluconazole (FCZ) were studied with a Bio-Cell Tracer system. The numerical data were recorded as the original growth rate (Pre-GR), the time needed for FCZ reaching to its target in hypha (tau on), the growth rate under the FCZ ...
Jones D W - - 1999
Health Canada recently lowered the recommended maximum daily exposure of mercury from all sources for women of child-bearing age and for children less than 10 years. This new exposure guideline does not seem to be based on any new scientific finding of human toxicity. The average daily intake of methylmercury ...
Bourland C T - - 1999
Space food systems have evolved from tubes and cubes to Earth-like food being planned for the International Space Station. The weight, volume, and oxygen-enriched atmosphere constraints of earlier spacecraft severely limited the type of food that could be used. Food systems improved as spacecraft conditions became more habitable. Space food ...
Fukami K - - 1998
By using low-temperature, clean, and nutrient-rich properties of deep seawater (DSW; seawater below the euphotic layer), a continuous and simultaneous cultivation system for a benthic food diatom, Nitzschia sp., and juvenile abalone was established. Cell suspension of Nitzschia sp. was added to a bioreactor made of acrylic pipe (7 cm ...
Hansen J C - - 1998
The human health programme of the first phase of AMAP was planned at an international meeting held in Nuuk, Greenland, October 1992. As the most vulnerable period to adverse effects of contaminants is during fetal development, it was decided to concentrate on analyses of umbilical cord blood and maternal blood. ...
Watras C J - - 1998
Current paradigms regarding the bioaccumulation of mercury are rooted in observations that monomethyl mercury (meHg) biomagnifies along pelagic food chains. However, mechanisms regulating the formation of meHg, its initial incorporation at the base of pelagic food chains, and its subsequent trophic transfer remain controversial. Here we use field data from ...
Wagemann R - - 1998
Concentrations of methylmercury, total mercury and selenium in marine mammal tissues were determined in liver, muscle, skin (muktuk) and blubber of belugas, ringed seals and narwhal, using atomic absorption and capillary gas chromatography with ECD detection. Mean MeHg levels in the types of tissues analysed, except blubber, generally exceeded the ...
Kehrig H A - - 1998
We analyzed mercury levels in the white muscular tissue of a fish (Micropogonias furnieri) originated from four Brazilian estuaries during the period between the summer 1990 and spring 1991. Mercury levels were below the maximum permissible limit established for food by the Brazilian legislation (500.0 ng.g-1 wet wt.). The measured ...
Renzoni A - - 1998
Mercury was not regarded as a pollutant of primary importance until many deaths due to mercury poisoning occurred in the 1950s. More recently, adverse health effects have been documented at relatively low exposure levels, and monitoring data must now be interpreted in this light. The Mediterranean basin has been studied ...
Berglund A - - 1998
Since the results of a preliminary study have shown that the magnetic fields of some visual display units (VDUs) increased the release of mercury from amalgam specimens, the aim of the present study was to examine whether exposure to magnetic fields might affect the mercury vapor release from amalgam restorations ...
Kannan K - - 1998
Concentrations of total mercury and methyl mercury were determined in sediment and fish collected from estuarine waters of Florida to understand their distribution and partitioning. Total mercury concentrations in sediments ranged from 1 to 219 ng/g dry wt. Methyl mercury accounted for, on average, 0.77% of total mercury in sediment. ...
Lodenius M - - 1998
Release and spreading of mercury from gold mining is a widespread problem in the Amazon area. Today we have rather good knowledge of the mercury situation. Tens of investigations have considered mainly concentrations in fish and human hair. Metallic mercury is used for amalgamation of gold, and the mercury is ...
Nishida H - - 1998
A new electrode (HN-5) for measuring cochlear microphonics (CMs) in extratympanic (ET) electrocochleography (ECochG) has been developed. The HN-5 electrode consists of a silver wire 2 mm in diameter and 5.0 cm in length connected to a low noise cable. The HN-5 electrode showed low impedance and excellent frequency characteristics. ...
Henry K S - - 1998
Concentrations of PCBs, DDTs, toxaphene, chlordanes, dieldrin, and mercury were determined in smallmouth bass (Micropterus dolomieui) collected from Fumee Lake, a remote lake in the Upper Peninsula of Michigan. An ecological hazard assessment was conducted to determine potential impacts of contaminants on bald eagles and mink eating fish from this ...
Arranz A - - 1997
The electroanalytical behaviour of the herbicide Nitralin has been studied by means of different voltammetric techniques. Nitralin is adsorbed on the mercury electrode and gives 2 reduction waves at -0.6 and -0.7 V versus Ag AgCl reference electrode, for pH values > 10. The electrochemical process is irreversible and strongly ...
Burger J - - 1997
There is an abundance of field data on levels of mercury in a variety of organisms and there are a number of studies that demonstrate the adverse effects of mercury on laboratory animals, but few studies examine the relationship between the two. Thus it is often difficult to determine the ...
Benítez P - - 1997
The design of a new type of two-mirror solar concentrator for a tubular receiver, the XX concentrator, is presented. The main feature of the XX is that it has a sizable gap between the secondary mirror and the absorber and it still achieves concentrations close to the thermodynamic limit with ...
Falandysz J - - 1997
The total concentration of mercury was determined in 15 species of wild growing mushrooms, each represented by 15 specimens including underlying substrate, collected from the unpolluted area of the sand-bar Mierzeja Wiƛlana in the northern part of Poland in 1993-1994. Mercury was measured by cold vapour atomic absorption spectrometry (CV-AAS) ...
Hansen J C - - 1997
As a natural element, mercury is ubiquitous in the environment. The largest amount of mercury, amounting to approximately 100,000 tons per year, originates from the degassing of the earth's crust. To this amount, such anthropogenic activities as combustion of fossil fuels and releases from industrial activities add approximately 20,000 tons ...
Mollenhauer H H - - 1997
Epoxy resins are mixtures of several components formulated in exact proportions to assure proper polymerization. It is necessary that this composition be maintained throughout the tissue being infiltrated to avoid embedding artifacts. Unfortunately, the separate resin components will not penetrate the tissue at the same rate unless they all have ...
Heaton-Jones T G - - 1997
Thirty American alligators (Alligator mississippiensis), including 24 wild-caught and six control captive farm-raised alligators, were analyzed for whole body mercury contamination. Wild-caught animals were collected from Water Conservation Area 3 in the Everglades ecosystem (n = 12) and from Alachua, Brevard, and Collier counties outside the Everglades (n = 12). ...
Pépin G - - 1997
We have presented the results concerning 135 judicial expert opinion over a 3-year period. We have compared the measured levels in hair of 6-acetylmorphine (6-AM) and of cocaine with the habitual use declared by the consumers. This allows us to propose three levels (low, medium, high) of consumption in relation ...
Clarkson T W - - 1997
The major physical forms of mercury to which humans are exposed are mercury vapor, Hg0, and methylmercury compounds, Ch3HgX. Mercury vapor emitted from both natural and anthropogenic sources is globally distributed in the atmosphere. It is returned as a water-soluble form in precipitation and finds its way into bodies of ...
de Moraes L A - - 1997
Total mercury concentrations were measured in dorsal muscle tissue of two edible fish species, Prochilodus scrofa 'curimba' and Pseudoplatystoma corruscans 'pintado', respectively detritivorous and carnivorous. Fish species were sampled monthly between February 1993 and January 1994 and bimonthly between April 1994 and February 1995 in three subsystems of Paraná river' ...
Morgan J N - - 1997
The effects of cooking practices commonly used by Native Americans on total mercury concentrations in fish were investigated. A preparation factor relating mercury concentrations in fish as prepared for consumption to mercury concentration data as measured in typical environmental monitoring programs was calculated. Preparation factors are needed to provide risk ...
McNeish A S - - 1997
Blue mussels (Mytilus edulis) from the Mersey and Dee Estuaries have been found to contain high concentrations of alpha-MHCH (methyl hexachlorocyclohexane) and gamma-MHCH (methyl lindane), and a series of other methylated isomers of MHCH. Mean values for SigmaMHCH in mussels declined serially from Rock Ferry (81.4 +/- 19.3 microg kg(-1)), ...
Brett C M - - 1996
Batch-injection analysis exhibits the advantages of rapid and simple electroanalysis of microlitre samples. Nafion-coated mercury thin film electrodes have been evaluated for use in batch-injection analysis with anodic stripping voltammetry (BIA-ASV). The advantages of Nafion-coated electrodes in reducing electrode contamination by components of complex matrices are combined with the analysis ...
Gualix J - - 1996
Adenosine 5'-tetraphosphate (Ap4) is a natural constituent of chromaffin granules with concentration values of 2.2 +/- 0.1 nmol/mg of protein and a ratio 245 +/- 40 times lower with respect to ATP (n = 4). The granular transport of epsilon-ATP resulted in a time- and concentration-dependent production of epsilon-adenosine tetraphosphate ...
Dietz R - - 1996
Baseline concentrations of lead, cadmium, mercury and selenium are reported from different tissues in marine organisms from Greenland. Overall, lead levels in marine organisms from Greenland are low, whereas cadmium, mercury and selenium levels are high. Tissue differences are not very distinct for lead, whereas the opposite is the case ...
Wagemann R - - 1996
Concentrations of mercury, cadmium, and other heavy metals in tissues of belugas (Delphinapterus leucas), narwhal (Monodon monoceros) and ringed seals (Phoca hispida) from across the Canadian Arctic are reported. Published and new information is used to provide an overview of metals in tissues of these animals, to delineate the existence ...
Weihe P - - 1996
In the Faroe Islands marine food constitutes a considerable part of the diet. In addition to fish, both meat and blubber from pilot whales are included in the diet. Muscle tissue of pilot whales caught in the Faroe Islands contains an average mercury concentration of 3.3 micrograms/g (16 nmol/g), about ...
Guimarães J R - - 1996
Different aspects of mercury accumulation, retention, and elimination in temperate fish species have been reported, but few data are available for tropical species. In this work Hg accumulation in Trichomycterus zonatus, where experimental losses were estimated, was studied. Forty individuals (males and females) of T. zonatus were acclimatized for 30 ...
Kennedy J P - - 1996
A new hot-melt fluid bed coating process has been developed, characterized, and optimized. Polyethylene glycol served as the model coating agent and was charged with substrate into the fluid bed chamber in the solid state. The processing stages included: (A) warm-up, (B) preheating, (C) melting-spreading, and (D) cooling-congealing. A central ...
Woods J S - - 1996
Changes in urinary porphyrin excretion patterns (porphyrin profiles) have been described in response to a variety of drugs and chemicals. The present studies were conducted to define the specific changes in the urinary porphyrin profile associated with prolonged exposure to mercury and mercury compounds. In rats, exposure for a prolonged ...
Malm O - - 1995
Mercury is being released in the Amazon in an abusive way due to goldmining activities. The Tapajós river basin was the first to be intensively exploited in the modern Amazon gold rush. Fish and hair samples as the best indicators of human methylmercury contamination were investigated in the main cities ...
Buzina R - - 1995
A study was conducted to examine human exposure to mercury through dietary mercury intake in a population living in an industrially non-polluted area of the Adriatic Sea. The results have shown that approximately 20% of the subjects had a weekly dietary mercury intake above the provisional tolerable weekly intake (PTWI), ...
Chan H M - - 1995
Chronic metal toxicity is a concern in the Canadian Arctic because of the findings of high metal levels in wildlife animals and the fact that traditional food constitutes a major component of the diet of indigenous peoples. We examined exposure to trace metals through traditional food resources for Inuit living ...
Nakagawa R - - 1995
Several factors that influence the total mercury levels in atmosphere concentrations of mercury in Japan were investigated. The daily variation in the mercury content of air was ascribed to daily temperature differences. The maximum amount of mercury in air was found at about 1:00 pm; much smaller amounts were found ...
Palheta D - - 1995
A massive increase in gold mining in the Amazon region of Brazil has led to an enormous discharge of metallic mercury into the aquatic ecosystem. To investigate the dispersion, total and inorganic mercury concentrations were measured in water, fish and animal tissues, and in blood, urine and hair from members ...
Kuehl D W - - 1995
Polychlorinated biphenyls (PCBs), cis-chlordane, oxychlordane, heptachlor epoxide, mirex, hexachlorobenzene (HCB), lindane, octachlorostyrene (OCS), p,p'-DDE,p,p'-DDT, dieldrin, triphenylphosphate (TPP), polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PB-DPEs) were measured in the blubber, and five metals (mercury, lead, cadmium, chromium, and manganese) and selenium were measured in the liver of bottlenose dolphins (Tursiops ...
Halbach S - - 1995
Amalgam fillings constitute, after food, the main source of exposure to mercury for the general population. Banning amalgam would incur huge costs for additional dental treatment. An evaluation of potential health risks must be based on the mercury dose released from fillings. In this study, dose is estimated by a ...
Field R W - - 1995
A point-of-use waterborne radon-222 (222Rn) survey of a small Iowa town was performed to determine the cause of unnaturally high waterborne 222Rn concentrations in the municipality. The source of the elevated 222Rn concentrations was a newly discovered reservoir of waterborne 222Rn originating from distribution-system radium-226 (226Ra) adsorbed internal pipe scale ...
Aposhian H V - - 1995
Four chelating agents that have been used most commonly for the treatment of humans intoxicated with lead, mercury, arsenic or other heavy metals and metalloids are reviewed as to their advantages, disadvantages, metabolism and specificity. Of these, CaNa2EDTA and dimercaprol (British anti-lewisite, BAL) are becoming outmoded and can be expected ...
Sakai T - - 1995
Hair mercury concentrations were measured in 41 cats and 34 dogs living in Kanagawa, Saitama and Tokyo Prefectures. Total mercury concentrations measured by atomic absorption spectrometry were significantly higher (P < 0.01) in cats [7.40 parts per million (ppm) in males and 7.45 ppm in females] than in dogs (0.99 ...
Nielsen J B - - 1995
Females exposed to methylmercury expose their offspring to mercury across the placenta as well as through milk. The relative importance of these two routes of exposure has hitherto been unresolved. Using a cross-fostering model with female mice, the transplacental and lactational exposures to mercury were evaluated separately. In female mice ...
Cuadrado C - - 1995
This study was undertaken in order to monitor the intake of lead, cadmium and mercury in different geographical areas of Spain. The intakes of four populations were estimated from their habitual diets and compared with the Provisional Tolerable Weekly Intake (PTWI) or the Acceptable Daily Intake (ADI) to estimate the ...
Halbach S - - 1995
Amalgam fillings constitute, after food, the main source of exposure to mercury for the general population. An evaluation of potential health risks has to be based on the dose of mercury released from the fillings. This dose is estimated by a new procedure of mercury speciation which elutes the released ...
Schuhmacher M - - 1994
A total of 592 samples of 21 species of fish, cephalopods, crustaceans and molluscs were analyzed for mercury concentrations between November 1992 and February 1993 at four sites on the Tarragona coast in Catalonia, Spain. The results of this study show that mercury discharges into the marine environment of Tarragona ...
Mohan S B - - 1994
Commercially available beer, which is a dilute solution containing components of yeast, malt, and hop used in the manufacture of the beer, was used as a model system to demonstrate the potential of foam fractionation beyond the primary foaming stage. Most of the components present in the beer concentrated in ...
< 3 4 5 6 7 8 9 10 11 12 13 >