Search results for "Platinum"

Platinum and rhodium associated with the leaves of Nerium oleander L.; analytical method using voltammetry; assessment of air quality in the Palermo …

2009

Abstract A rapid accumulation of the catalytic active noble metals in the environmental and biological matrices was observed and concern arose about potential environmental and health risks. The development of reliable analytic methods to measure very low Pt and Rh concentrations is required. The main purpose of this work was to develop a reliable method for the determination of Pt and Rh in environmental matrices because of inherent difficulties in using conventional techniques used, in particular, the ICP-OES technique. A direct determination of Pt using ICP-MS, for instance, is problematic, due to interfering signals. In this work, differential pulse voltammetry (DPV/a) and adsorptive st…

Occurrence of platinum, palladium and gold in pine needles of Pinus pinea L. from the city of Palermo (Italy)

2003

Abstract Preliminary data on the presence of Pt, Pd and Au in airborne particulate matter from the urban area of Palermo (Sicily, Italy) are presented. They were obtained by analysing 40 samples of pine needles (Pinus pinea L.) collected in and around the city. Observed concentrations range from 1 to 102 μg/kg for Pt, 1 to 45 μg/kg for Pd and 22 to 776 μg/kg for Au. Platinum and Pd concentrations in pine needles are up to two orders of magnitude higher than their crustal abundances. They exhibit a high statistical correlation (R2=0.74) which suggests a common origin. Precious metal concentrations measured within the city centre are much higher than those occurring outside the town. The dist…

Oxidative Addition of Halogens on Open Metal Sites in a Microporous Spin-Crossover Coordination Polymer

2009

Polynuclear complexes of Pt(II) with polypyridyl ligands.II.Synthesis, spectroscopic and structural characterization and cytotoxic activity

2007

Cardiac Glycosides Exert Anticancer Effects by Inducing Immunogenic Cell Death

2012

Some successful chemotherapeutics, notably anthracyclines and oxaliplatin, induce a type of cell stress and death that is immunogenic, hence converting the patient's dying cancer cells into a vaccine that stimulates antitumor immune responses. By means of a fluorescence microscopy platform that allows for the automated detection of the biochemical hallmarks of such a peculiar cell death modality, we identified cardiac glycosides (CGs) as exceptionally efficient inducers of immunogenic cell death, an effect that was associated with the in- hibition of the plasma membrane Na + - and K + -dependent adenosine triphosphatase (Na + /K + -ATPase). CGs ex- acerbated the antineoplastic effects of DN…

Mechanism of aminocarbene formation by nucleophilic attack on isocyanide ligands in platinum(II)2-pyrazyl and 4-pyridyl complexes

1997

Abstract The reactions of 2-pyrazyl and 4-pyridyl isocyanide complexes [Pt(CNC 6 H 11 )(C 4 H 3 N 2 - C 2 )(dppe)ClO 4 and [Pt(CNC 6 H 11 )(C 5 H 4 N- C 4 ) (dppe)]ClO 4 ( 1 ) with amines involving the formation of aminocarbene derivatives have been studied kinetically in 1,2-dichloroethane by UV—VIS techniques. The kinetics obey the simple second-order rate law rate = k 2 [ 1 ][amine]. Low activation enthalpies and highly negative activation entropies for the k 2 term are observed. A mechanism is proposed involving direct nucleophilic attack of the amine on the isocyanide carbon with concomitant proton transfer from the amine to the isocyanide nitrogen assisted by the heterocyclic nitrogen…

Hydrogen bonding patterns of 7,9-dimethylguanine and its transplatinum(II) complexes

2002

Methylation at the N7 position is one of the most frequently naturally occurring modifications of guanosine. This alteration drastically changes the hydrogen bonding and acid–base properties of the guanine nucleobase. Here we show on the example of the model nucleobase 7,9-dimethylguanine that due to blockage of N7 of the purine ring, new hydrogen bonding patterns occur on the minor groove binding face of this nucleobase involving the ring nitrogen N3 and the exocyclic amino group N2H2. The free 7,9-dimethylguaninium ion and several transplatinum(II) complexes of the this ligand are presented and discussed. Methylation at N7 drastically changes the acid–base and hydrogen bonding properties …

Semipermeable membrane to retain platinum atoms in the electrodeposition process of alpha spectrometry sources

1998

Abstract In earlier work alpha sources electrodeposited on stainless steel backings were analyzed by X-ray fluorescence (XRF) and Rutherford backscattering spectrometry (RBS) finding that during the electrodeposition process large quantities of platinum from the anode were deposited on the cathode surface jointly with the actinides. In the present work, a method to retain platinum atoms using an electrodeposition cell with a semipermeable membrane located between anode and cathode is proposed and tested. The XRF and RBS of alpha sources electrodeposited using this method show that there is less platinum on the stainless steel backing, thereby improving the quality of sources to be measured …

Isotope dilution inductively coupled plasma quadrupole mass spectrometry in connection with a chromatographic separation for ultra trace determinatio…

2000

An isotope dilution inductively coupled plasma quadrupole mass spectrometric (ID-ICP-QMS) method was developed for the simultaneous determination of the platinum group elements Pt, Pd, Ru, and Ir in environmental samples. Spike solutions, enriched with the isotopes 194Pt, 108Pd, 99Ru, and 191Ir, were used for the isotope dilution step. Interfering elements were eliminated by chromatographic separation using an anion-exchange resin. Samples were dissolved with aqua regia in a high pressure asher. Additional dissolution of possible silicate portions by hydrofluoric acid was usually not necessary. Detection limits of 0.15 ng x g(-1), 0.075 ng x g(-1), and 0.015 ng x g(-1) were achieved for Pt,…

Ureteral Stones: Shockwave Lithotripsy or Ureteroscopy, Which is Best?

2021

Background Renal stone disease is common and can cause emergency presentation with acute pain due to ureteric colic. International guidelines have stated the need for a multicentre randomised controlled trial (RCT) to determine whether a non-invasive outpatient (shockwave lithotripsy [SWL]) or surgical (ureteroscopy [URS]) intervention should be the first-line treatment for those needing active intervention. This has implications for shaping clinical pathways. Objective To report a pragmatic multicentre non-inferiority RCT comparing SWL with URS. Design, setting, and participants This trial tested for non-inferiority of up to two sessions of SWL compared with URS as initial treatment for ur…