The interaction of CT DNA by two anionic Ru(III) complexes with N-substituted salicylidenimine ligands was investigated by spectroscopic titration and cyclic voltammetry. The result gives a surprising evidence for intercalation of DNA by the negatively charged complex species containing non typical intercalating ligands with Kb of order 10 M. Na[RuCl2(N-R-5-X-salim)2], where R represents butyl or phenyl and X = H, Cl, were characterized on the basis of elemental analysis, MALDI-TOF mass spectrometry, infrared, UV / visible spectroscopic measurements and cyclic voltammetry. (doi: 10.5562/cca2216)
To make jewellery of gold, gold is alloyed with other metals. It is of great importance to accurately determine the total amount of pure gold in alloys used for making the jewellery and in jewellery made of gold, because it determines its value on the market. Several analytical methods are used for this purpose. This study was based on comparison of results of analysis of gold alloy for 14-carat jewellery obtained by non-destructive fluorescent analysis method and destructive cupellation method. The null hypothesis with 95 % confidence level on equivalence in measurement precision of perecnt by percent mass of gold in three very similar gold alloy samples in reproducibility conditions (three measurement series) for standard cupellation method and the method compared (validated), XRF method, has been confirmed. F-test did not confirm null hypothesis on precision equivalence for two mentioned analysis methods. There is a significant difference in variance values. However, the t-test was carried out, which verified the null hypothesis on equivalence between mean values of results achieved in two compared values. In order to confirm applicabilty of two methods ,Zscore was calculated giving values of less than 2, using statistical data from inter-laboratory program with 62 participating laboratories applying cupellation method, and 60 laboratories applying XRF method for analysis of gold alloy used in production of 14-carat jewellery. Article info Received: 06/12/2011 Accepted: 25/01/2012
UNLABELLED The objective of this study was to evaluate cortisol in the saliva and serum of healthy persons and its daily fluctuations by using immunochemical method on a autoanalyzer. Biological samples: Serum from 14 healthy persons and saliva from 18 healthy persons were taken two times at 8 a.m. and at 4 p.m. Immunochemical assay: The principle of this method is the competitive binding of cortisol present in the analyzed sample and cortisol marked with peroxides on binding parts with specific antibodies. STATISTICAL ANALYSIS Student t-test. Cortisol in saliva in the morning: 21,2 +/- 16,2 nmol/l and in the afternoon 12,7 +/- 8,1 nmol/l. Cortisol in serum in the morning: 459, 6 +/- 235,2 nmol/l , and in the afternoon 340,5 +/- 207,5 nmol/l. The concentrations of cortisol in saliva are lower than in serum. Cortisol in the serum in the morning is about twenty times higher than cortisol in the saliva at the same time. Cortisol in the serum at afternoon is about twenty-seven times higher than cortisol in the saliva. Individual variabilities of cortisol in the saliva and serum were found during the day.
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