110 research outputs found
TrainMiC, Training in Metrology in Chemistry.
Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel
Brain iron accumulation in Wilson disease: a post-mortem 7 Tesla MRI - histopathological study
Aims: In Wilson disease (WD), T2/T2*-weighted (T2*w) MRI frequently shows hypointensity in the basal ganglia that is suggestive of paramagnetic deposits. It is currently unknown whether this hypointensity is related to copper or iron deposition. We examined the neuropathological correlate of this MRI pattern, particularly in relation to iron and copper concentrations. Methods: Brain slices from nine WD and six control cases were investigated using a 7T-MRI system. High resolution T2*w images were acquired and R2* parametric maps were reconstructed using a multi-gradient recalled echo sequence. R2* was measured in the globus pallidus (GP) and the putamen. Corresponding histopathological sections containing the lentiform nucleus were examined using Turnbull iron staining, and double staining combining Turnbull with immunohistochemistry for macrophages or astrocytes. Quantitative densitometry of the iron staining as well as copper and iron concentrations were measured in the GP and putamen and correlated to R2* values. Results: T2*w hypointensity in the GP and/or putamen was apparent in WD cases and R2* values correlated with quantitative densitometry of iron staining. In WD, iron and copper concentrations were increased in the putamen compared to controls. R2* was correlated with the iron concentration in the GP and putamen whereas no correlation was observed for the copper concentration. Patients with more pronounced pathological severity in the putamen displayed increased iron concentration, which correlated with an elevated number of iron-containing macrophages. Conclusions: T2/T2*w hypointensity observed in vivo in the basal ganglia of WD patients is related to iron rather than copper deposits
Critical assessment of the elemental composition of Corning archeological reference glasses by LA-ICP-MS
Corning archeological reference glasses A, B, C, and D have been made to simulate different historic technologies of glass production and are used as standards in historic glass investigations. In this work, nanoseconds (193, 266 nm) and femtosecond (800 nm) laser ablation were used to study the elemental composition of Corning glasses using laser ablation inductively coupled plasma mass spectrometry. The determined concentrations of 26 oxides (Li2O, B2O3, Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, V2O5, Cr2O3, MnO, Fe2O3, CoO, NiO, CuO, ZnO, Rb2O, SrO, ZrO2, SnO2, Sb2O5, BaO, PbO, Bi2O3) are compared with values reported in the literature. Results show variable discrepancies between the data, with the largest differences found for Cr2O3 in Corning A; Li2O, B2O3, and Cr2O3 in Corning B; and MnO, Sb2O5, Cr2O3, and Bi2O3 in Corning C. The best agreement between the measured and literature values was found for Corning D. However, even for this reference, glass re-evaluation of the data was necessary and new values for PbO, BaO, and Bi2O3 are proposed
Neurochemical and Behavioral Characteristics of Toxic Milk Mice: An Animal Model of Wilson’s Disease
Problemy zachowania spójności pomiarowej w chromatografii gazowej
Techniki chromatograficzne, dzięki możliwości rozdzielania i identyfikacji składników często bardzo złożonych mieszanin, zdominowały współczesne laboratoria analityczne. Ważnym elementem zapewnienia jakości wyników jest wzorcowanie układów chromatograficznych tak, aby zastosowane wzorce chemiczne umożliwiły zapewnienie spójności pomiarowej. Poza tym należy pamiętać o tym, aby proces wzorcowania stanowił element procesu nadzoru nad wyposażeniem pomiarowym.Thanks to the possibility of separation and identification of components of the frequently very complex mixtures makes the chromatographic techniques dominated modern method in analytical laboratories. An important element in ensuring the quality of the results is the calibration of chromatographic systems, so that the used chemical standards make possible the retention of measurement integrity. Moreover it must be kept in mind that the calibration process should be a part of supervision process over the measuring equipment
On the use of atomic and mass spectrometry for the investigation of chemical speciation
Selected examples of studies conducted by the research group from Laboratory
of the Basic Aspect of Analytical Chemistry (Faculty of Chemistry, University of
Warsaw), related to the investigation of chemical speciation with the use of coupled
techniques were discussed in this work. The pioneering investigation was focused
on the study of the speciation of mercury in fish tissues and in clinical samples.
Then, the intensive researches were conducted towards understanding of the speciation
of antimony and selenium in water, plants and clinical objects. Interestingly,
the evaluation of the speciation of aluminium become a challenge in respect of the
establishing of the reliable analytical procedure, and the use of flow injection for
sample operation were explored in this case. The last but not least, the non – routine
analytical procedure was developed in the case of zinc speciation in plant exposed
to the harmful environmental conditions
Intercalation compounds of graphite in atomic absorption spectrometry
The significance of the formation of intercalation compounds of graphite in the atomization process for atomic absorption spectrometric measurements was investigated. The inspection of the graphite surface and subsurface regions was performed by electron probe microanalysis with energy dispersive X-ray spectroscopic (EDX) detection. It was found that chloride forms thermally stable graphite intercalation compounds (GIC) with the graphite of tubes, which was either non-modified or modified with noble metals
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