نتایج جستجو برای: metal ion
تعداد نتایج: 385192 فیلتر نتایج به سال:
A systematic review and meta-analysis of trials comparing hip resurfacing to metal-on-metal total hip arthroplasty was conducted to determine if there is a difference in serum metal ion levels in patients receiving these implants. EMBASE and MEDLINE databases were searched from inception to December 2010 for all trials involving the use of these devices. Eligibility for inclusion in the review ...
The role of metal cations (Mg(2+)) in the cleavage reaction of fully hydrated RNA enzymes is investigated via Car-Parrinello calculations. We find that the action of two metal catalysts is the most efficient way to promote, on one hand, the proton abstraction from O(2)(')-H that triggers the nucleophilic attack and, on the other hand, the weakening and subsequent cleavage of the P-O(5)(') bond....
a chelating resin is prepared by condensation polymerization of aniline with formaldehyde andcharacterized by ft-ir, elemental analysis and studied for the preconcentration and determination of traceplatinum ion from environmental water sample using inductively coupled plasma-atomic emission spectroscopy(icp-aes). the optimum ph value for sorption of the metal ions was 5. the maximum adsorption...
It has long been known that type II topoisomerases require divalent metal ions in order to cleave DNA. Kinetic, mutagenesis and structural studies indicate that the eukaryotic enzymes utilize a novel variant of the canonical two-metal-ion mechanism to promote DNA scission. However, the role of metal ions in the cleavage reaction mediated by bacterial type II enzymes has been controversial. Ther...
Mercury ion (Hg2+) is recognized as one of the most toxic metal ions for the environment and for human health. Techniques utilized in the detection of Hg2+ are an important factor. Herein, a simple thymine was successfully employed as the surface enhanced Raman spectroscopy sensor for Hg2+ ion detection. The limit of detection (LOD) of the developed sensor is better than 0.1 nM (0.02 ppb). This...
The present work is carried out to study the antioxidant potential of ethanolic extract of Alstonia scholaris Linn. ( Apocynaceae ) using various in vitro tests including 1,1-diphenyl-2-picryl-hydrazil (DPPH . ) free radical scavenging, metal ion chelating, hydrogen peroxide scavenging, superoxide anion radical scavenging, and ferric thiocyanate reducing ability. Ethanolic ex...
The occurrence of pseudotumours (soft tissue masses relating to the hip joint) following metal-on-metal hip resurfacing arthroplasty has been associated with higher than normal bearing wear and high serum metal ion levels although both these findings do not necessarily coexist. The purpose of this study was to examine patient activity patterns and their influence on acetabular component edge lo...
A binding study of nickel ions by a new recombinant human Growth Hormone (hGH), produced as an injected drug, has been done at 27˚C in NaCl solution (50 mM) using an isothermal titration calorimetry. There is a set of three identical and non-interacting binding sites for nickel ions. The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 40 μM and -16...
The complexation reactions between N,N'-3,6-dioxa-1,8-octanebis (salicylaldimine) [saldioxen(I)] and Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) were studied spectrophotometrically in methanol solution at 25 °C. The stoichiometry of the complexes were obtained as 2:1 and 1:1 sadioxen-metal ion using mole ratio method. The formation constants of the complexes were determined, a...
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