Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Samples of chrysotile from Quebec (UICC B and Jeffrey 4T-30) and from the Coalinga region of California (Calidria RG-144) were irradiated with thermal neutrons in a reactor. The main activation products induced were 46Sc, 51Cr, 59Fe and 60Co. Accurately weighed samples of the irradiated materials were dispersed in N HCl by hand shaking for 10 s. After leaching for predetermined periods at 25 degrees C, the samples were filtered and the concentrations of Mg determined in the filtrates by inductively-coupled plasma atomic emission spectrometry (IPC-AES) and the activities of the four radionuclides by high resolution gamma-ray spectrometry. Similar measurements were made on solutions obtained by refluxing samples of irradiated chrysotile with 2N HCl for 2 h. The specific activities of each of the four activation products were calculated in arbitrary units and, as the concentrations of Sc, Cr, Fe and Co in the UICC B sample had already been determined, it was possible to estimate the concentrations of these elements in the other two samples. Similarities in the leaching patterns of magnesium and of the activation products showed that with all samples, high proportions of the parent trace elements were present in the form of isomorphous substitutes for magnesium in structural brucite. Agreement was closest with the Calidria chrysotile in which all the radionuclides had a similar pattern. With the Jeffrey and UICC B samples, the presence of a high proportion of the iron as relatively insoluble magnetite accounted for the observed discrepancy in behaviour between 59Fe and Mg. More detailed calculation of leaching rates over specific time intervals showed that, initially, 51Cr and 60Co dissolved more rapidly than Mg but that this was followed by a period in which the opposite was the case. It was concluded that the Calidria RG-144 sample is an ideal candidate for studies of magnesium dissolution in vivo.
 ...
PMID:Acid leaching studies of neutron-irradiated chyrsotile asbestos. 920 54

The Waste Extraction Test (WET) is used in California as a complement to the Toxicity Characteristic Leaching Procedure (TCLP). The WET protocol consists of shaking a sample with citrate buffer and determining the metal content in the solution produced. This procedure requires a 1-to-10 waste-to-liquid ratio and 48 h for extraction. Although the WET protocol proves to be very useful, it is a time-consuming step in the determination of leaching and mobility. Therefore, a microwave extraction procedure was optimized to emulate the relative extraction efficiency obtained by the WET protocol. Lead, arsenic, and copper concentrations were measured by inductively coupled plasma mass or atomic spectrometry (ICP-MS or ICP-AES), following a strict quality assurance protocol. Results obtained with this new methodology were statistically comparable to those obtained by the WET protocol. This microwave extraction approach proved simple and fast, reducing sample treatment by almost 280%. A significant reduction also occurs in waste production, materials, labor, and chemical usage. Therefore, the microwave extraction procedure is recommended as a rapid and cost effective monitoring tool for waste samples when combined with or supplemented by the traditional WET protocol.
 ...
PMID:Comparison of microwave-assisted extraction and waste extraction test (WET) preparation for inductively coupled plasma spectroscopic analyses of waste samples. 1232 46

In this work the lipophilicity of different selenium species occurring in environmental matrices and food, Se(IV), Se(VI), selenomethionine (Se-Met), selenocystamine (Se-CM), selenocystine (Se-Cyst), and dimethyl diselenide (CH3)2Se2, was investigated in the octanol-water system, using the shaking flask method and detection with inductively coupled plasma-atomic emission spectrometry (ICP-AES), in order to assess their environmental fate and tendency to bioaccumulate. Polarography was also used for the electrochemically active Se species, Se(IV), Se-Cyst, Se-CM and (CH3)2Se2, and the results were compared with those measured by ICP-AES. Furthermore, the influence of pH was studied by determining the logarithm of the distribution coefficient, log D, at three pH values, 5, 7, and 9, as was the impact of the marine environment on the lipophilicity profile of the six investigated Se species. The results were compared with those estimated approximately by use of PrologD software, based on the Ghose-Crippen log P (P: partition coefficient) calculation system, the only system which incorporates values-even though approximate-for the atom type of Se. Finally, from our experimental data an indicative value of the Se-Se fragment for log P prediction, for use in drug design, was estimated.
 ...
PMID:Study of the lipophilicity of selenium species. 1560 37

The sorption of hexavalent chromium, Cr(VI), from aqueous solutions on macroporous resins containing tertiary amine groups (Lewatit MP 62 and Lewatit M 610) was studied at varying Cr(VI) concentrations, adsorbent dose, pH, contact time and temperatures. The concentration of chromium in aqueous solution was determined by inductively coupled plasma spectrometry (ICP-AES). Batch shaking sorption experiments were carried out to evaluate the performance of Lewatit MP 62 and Lewatit M 610 anion exchange resins in the removal of Cr(VI) from aqueous solutions. The ion-exchange process, which is pH dependent, shows maximum removal of Cr(VI) in the pH range 2-6 for an initial Cr(VI) concentration of 100 ppm. The sorption increases with the decrease in pH and slightly decreases with the increase in temperature. Both ion exchangers had high bonding constants with Lewatit M 610 showing stronger binding. It was observed that the maximum adsorption capacity of 0.40 mmol of Cr(VI)/g for Lewatit MP 62 and 0.41 mmol of Cr(VI)/g for Lewatit M 610 was achieved at pH of 5.0. The thermodynamic parameters (free energy change, DeltaG degrees ; enthalpy change, DeltaS degrees ; and entropy change, DeltaH degrees ) for the sorption have been evaluated. The rise in temperature caused a slight decrease in the value of the equilibrium constant (Kc) for the sorption of Cr(VI) ion. The sorption of Cr(VI) on the resin was rapid during the first 15 min and equilibrium was found to be attained within 30 min. The sorption of Cr(VI) onto the resins followed reversible first-order rate kinetics. Such ion exchange resins can be used for the efficient removal of chromium from water and wastewater.
 ...
PMID:Removal of Cr(VI) from aqueous solution by two Lewatit-anion exchange resins. 1575 63

A robust oxygen-flask combustion system was developed using light beam ignition. An appropriate amount of environmental sample was wrapped with a small piece of filter paper and held in a basket made of platinum-zirconium spiral. After the sample was inserted into an oxygen-filled flask containing an acid mixture, the light beam from an overhead projector lamp was focused to ignite the sample. The combusted products were absorbed into the acid mixture by shaking the flask and then used for the ICP-AES measurement of metals. The proposed method was successfully applied to the determination of metals in Environmental Standard Reference Materials and Artemia salina. The present method is also applicable to ion chromatographic measurements of chlorine in polyvinyl chloride wall paper by using hydrogen peroxide as absorbent.
 ...
PMID:Oxygen-flask combustion with light beam ignition. 1827 Apr 24

A system for separation of zinc traces from large amounts of cadmium is proposed in this paper. It is based on the solid-phase extraction of the zinc in the form of thiocyanate complexes by the polyurethane foam. The following parameters were studied: effect of pH and of the thiocyanate concentration on the zinc extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction, conditions for the separation of zinc from cadmium, influence of other cations and anions on the zinc sorption by PU foam, and required conditions for back extraction of zinc from the PU foam. The results show that zinc traces can be separated from large amounts of cadmium at pH 3.0+/-0.50, with the range of thiocyanate concentration from 0.15 to 0.20 mol l(-1), and the shaking time of 5 min. The back extraction of zinc can be done by shaking it with water for 10 min. Calcium, barium, strontium, magnesium, aluminum, nickel and iron(II) are efficiently separated. Iron(III), copper(II) and cobalt(II) are extracted simultaneously with zinc, but the iron reduction with ascorbic acid and the use of citrate to mask copper(II) and cobalt(II) increase the selectivity of the zinc extraction. The anions nitrate, chloride, sulfate, acetate, thiosulphate, tartarate, oxalate, fluoride, citrate, and carbonate do not affect the zinc extraction. Phosphate and EDTA must be absent. The method proposed was applied to determine zinc in cadmium salts using 4-(2-pyridylazo)-resorcinol (PAR) as a spectrophotometric reagent. The result achieved did not show significant difference in the accuracy and precision (95% confidence level) with those obtained by ICP-AES analysis.
 ...
PMID:Quantitative separation of zinc traces from cadmium matrices by solid-phase extraction with polyurethane foam. 1896 83

The migration tests of cadmium (Cd) and lead (Pb) from paint film on baby toys set out in the Japanese Food Sanitation Law (official standard) and International Standard 8124-3 (ISO) were compared. Vinyl chloride resin enamel and acrylic resin enamel containing 1,000 mg/kg Cd and Pb on a dried basis were painted on glass plates and then dried. According to the official standard, the paint films on the glass plates were soaked in water at 40 degrees C for 30 min and the solutions were analyzed by ICP-AES. Cd and Pb were below the limit of determinotion (<0.1 microg/mL) and were less than 1/5-1/10 of the official standard limits. When the solvent was changed to 4% acetic acid or 0.07 mol/L HCl, we found that 0.3-2.3 microg/mL Cd and Pb migrated from the acrylic resin enamel, but no migration was observed from the vinyl chloride resin enamel. Meanwhile, according to the ISO method, paint was scratched from the glass plates and the powder was soaked in 0.07 mol/L HCl at 37 degrees C for 1 hr either with shaking and without shaking. The migration of Cd and Pb reached 310 to 910 mg/kg, i.e., 3.5-12 times more than the migration limits. Cd migrated more extensively than Pb, and they both migrated more readily from the acrylic resin enamel than from the vinyl chloride enamel. In conclusion, the migration test of Cd and Pb from paint films on toys based on the ISO standards is stricter than that based on the Japanese Food Sanitation Low.
 ...
PMID:[Migration tests of cadmium and lead from paint film of baby toys]. 1943 59