Search results for "CHROMIUM"
showing 10 items of 494 documents
Filling the Gap in the Metallacrown Family: The 9‐MC‐3 Chromium Metallacrown
2021
Abstract In this work, we report on a long‐sought missing complex in the metallacrown family. We synthesized and characterized the novel chromium metallacrown (MC) complex {CrIII(μ 2‐piv)3[9‐MCCr(III)N(shi)‐3](morph)3}⋅MeOH (in which shi3−=salicyl hydroxamate, piv=pivalate, and morph=morpholine). The MC with a 9‐MC‐3 cavity of kinetically inert chromium(III) ions was synthesized by a solvothermal reaction. Magnetization measurements reveal a high spin ground state.
Producing SI-traceable reference values for Cd, Cr and Pb amount contents in polyethylene samples from the Polymer Elemental Reference Material (PERM…
2000
The present paper describes the certification of the amount content of Cd, Cr and Pb in two different polyethylene materials within the third phase of the Polyethylene Elemental Reference Material (PERM) project. The analytical procedure to establish the reference values for Cd, Cr and Pb amount contents in these materials is based on isotope dilution mass spectrometry used as a primary method of measurement. Cd and Pb were measured with inductively coupled plasma-mass spectrometry and Cr with positive thermal ionization-mass spectrometry. The decomposition of the polymer matrix was carried out using a high pressure asher. Reference values for amount content, traceable to the SI-system, hav…
Chromated metal products may be hazardous to patients with chromate allergy.
2009
Background: Hidden allergen exposure may contribute to persistence and relapse of chromate dermatitis. According to case reports, chromated metal products, such as screws, fittings, etc., may be relevant allergen sources for patients sensitized to chromate. Objectives: To examine concomitant patch test reactivity to potassium dichromate 0.5% petrolatum (pet.) and three different types of chromated metal rings. Patients/Methods: Patients with proven or suspected chromate allergy were patch tested with potassium dichromate 0.5% pet. and three different types of chromated metal rings (yellow, olive, and black). Hexavalent chromium Cr(VI) release from the patch tested rings was chemically an…
Comparison of cystatin C and creatinine-based glomerular filtration rate formulas with 51Cr-EDTA clearance in patients with cirrhosis
2011
Renal function is an important predictor of survival in cirrhosis and liver transplantation. GFR estimates using serum cystatin C (CysC) are proposed as better predictors of renal function than ones on the basis of serum creatinine (Cr). Our aims were: (1) evaluate correlations between serum CysC and different methods of creatinine measurements; (2) compare CysC and Cr GFR formulas with (51)Cr-EDTA; and (3) evaluate liver-related parameters potentially influencing GFR.254 blood samples in 65 patients with cirrhosis correlating CysC with four Cr methods were used; another 74 patients comparing (51)Cr-EDTA GFR to Modification of Diet in Renal Disease and Larsson and Hoek formulas for CysC wer…
Urinary metals and metal mixtures and oxidative stress biomarkers in an adult population from Spain: The Hortega Study
2019
Introduction: Few studies have investigated the role of exposure to metals and metal mixtures on oxidative stress in the general population. Objectives: We evaluated the cross-sectional association of urinary metal and metal mixtures with urinary oxidative stress biomarkers, including oxidized to reduced glutathione ratio (GSSG/GSH), malondialdehyde (MDA), and 8‑oxo‑7,8‑dihydroguanine (8-oxo-dG), in a representative sample of a general population from Spain (Hortega Study). Methods: Urine antimony (Sb), barium (Ba), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), molybdenum (Mo), vanadium (V) and zinc (Zn) were measured by ICPMS in 1440 Hortega Study participants. Results: The geomet…
The association of urine metals and metal mixtures with cardiovascular incidence in an adult population from Spain: the Hortega Follow-Up Study
2019
AbstractBackgroundThe association of low-level exposure to metals and metal mixtures with cardiovascular incidence in the general population has rarely been studied. We flexibly evaluated the association of urinary metals and metal mixtures concentrations with cardiovascular diseases in a representative sample of a general population from Spain.MethodsUrine antimony (Sb), barium (Ba), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), molybdenum (Mo), vanadium (V) and zinc (Zn) were measured in 1171 adults without clinical cardiovascular diseases, who participated in the Hortega Study. Cox proportional hazard models were used for evaluating the association between single metals and card…
The determination of trace element concentrations in fly ash samples using ultrasound-assisted digestion followed with inductively coupled plasma opt…
2009
Abstract A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of trace element (chromium, copper, lead, nickel, vanadium and zinc) concentrations in fly ash samples was developed. All the measurements were performed in robust plasma conditions. Ultrasound-assisted digestion procedures using digestion solutions of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 80% for all the analyte elements. Ultrasound-assisted two-step digestion with digestion solutions of 6 mL of HNO3 (Step 1) and 3 mL of HNO3 + 3 mL of HF (Step 2) resulted in recovery rates of over 92% for all the ana…
Pressure-induced magnetic switching and linkage isomerism in K0.4Fe4[Cr(CN)6]2.8 x 16 H2O: X-ray absorption and magnetic circular dichroism studies.
2008
The effect of applied pressure on the magnetic properties of the Prussian blue analogue K0.4Fe4[Cr(CN)6]2.8 x 16 H2O (1) has been analyzed by dc and ac magnetic susceptibility measurements. Under ambient conditions, 1 orders ferromagnetically at a critical temperature (T(C)) of 18.5 K. Under application of pressure in the 0-1200 MPa range, the magnetization of the material decreases and its critical temperature shifts to lower temperatures, reaching T(C) = 7.5 K at 1200 MPa. Pressure-dependent Raman and Mossbauer spectroscopy measurements show that this striking behavior is due to the isomerization of some Cr(III)-C[triple bond]N-Fe(II) linkages to the Cr(III)-N[triple bond]C-Fe(II) form. A…
Cr- and Sb-containing TiO 2 inorganic orange nano-pigments prepared by a relative long hydrocarbon chain polyol
2016
Abstract We report the preparation of a series of orange Cr- and Sb-containing TiO 2 nano-pigments by the polyol via using triethylenglycol (TEG). Poorly crystallized anatase nanopowders with nominal stoichiometric compositions Cr x Sb x Ti 1−2x O 2 , with 0 ≤ x ≤ 0.2, were obtained by heating at 180 °C a solution of antimony acetate, chromium acetylacetone and titanium butoxide in TEG. The transition temperature of the chromium- and antimonium-containing anatase nanoparticles into the rutile crystalline form occurred over the range of temperature between 500 and 650 °C, depending on the dopant amount. After annealing at 800 °C for short time the series of samples displaying the rutile stru…
Concurrent removal of Cr(III), Cu(II), and Pb(II) ions from water by multifunctional TiO2/Alg/FeNPs beads
2019
Abstract The use of multifunctional materials for water remediation is a modern approach where adsorption phenomena and heterogeneous photocatalysis can be applied for the removal of pollutants. Since the ideal remediation system should be able to remove both organic and inorganic pollutants, a crucial aspect to consider is the knowledge of operational parameters affecting the removal process, especially when heavy metal ions are present in concoction as in real systems. Given the proven efficiency of multifunctional TiO2/Alg/FeNPs magnetic beads for the removal of model organic pollutants, this study investigated the possibility to exploit such system also for the removal of mixed heavy me…