| 1. |
- Davidov, Eugene, et al.
(författare)
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Methods for the differential integrative omic analysis of plasma from a transgenic disease animal model
- 2004
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Ingår i: Omics. - : Mary Ann Liebert. - 1536-2310 .- 1557-8100. ; 8:4, s. 267-288
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Tidskriftsartikel (refereegranskat)abstract
- Multitiered quantitative analysis of biological systems is rapidly becoming the desired approach to study hierarchical functional interactions between proteins and metabolites. We describe here a novel systematic approach to analyze organisms with complex metabolic regulatory networks. By using precise analytical methods to measure biochemical constituents and their relative abundance in whole plasma of transgenic ApoE*3-Leiden mice and an isogenic wild-type control group, simultaneous snapshots of metabolic and protein states were obtained. Novel data processing and multivariate analysis tools such as Impurity Resolution Software (IMPRESS) and Windows-based linear fit program (WINLIN) were used to compare protein and metabolic profiles in parallel. Canonical correlations of the resulting data show quantitative relationships between heterogeneous components in the TG animals. These results, obtained solely from whole plasma analysis allowed us, in a rapid manner, to corroborate previous findings as well as find new events pertaining to dominant and peripheral events in lipoprotein metabolism of a genetically modified mammalian organism in relation to ApoE3, a key mediator of lipoprotein metabolism.
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| 2. |
- Kolczewski, C., et al.
(författare)
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Detailed study of pyridine at the C1s and N1s ionization thresholds : The influence of the vibrational fine structure
- 2001
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 115:14, s. 6426-6437
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Tidskriftsartikel (refereegranskat)abstract
- High resolution, vibrationally resolved, near-edge x-ray absorption fine structure (NEXAFS) spectra at the C 1s and N 1s ionization thresholds of pyridine and deuterated d(5)-pyridine in the gas phase have been recorded. The high resolution of 65 meV (150 meV) at the C s (N 1s) ionization thresholds reveals vibrational structures in the spectra. Detailed ab initio and density functional theory (DFT) calculations were performed to interpret the experimental spectra and to assign the observed peaks. In particular we focused on the previously unexplained intensity ratio for the two components of the C1s -->1 pi* transition. For this transition the vibrational structure is included through a linear coupling model in the DFT calculations and leads to the experimentally observed similar to2:3 intensity ratio between the two pi* components in the C1s spectrum rather than the similar to3:2 ratio obtained without vibrational effects. After inclusion of relaxation effects in the excited states, in addition to the vibrational effects, both theoretical methods yield almost perfect agreement with experiment.
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| 3. |
- Snell, James P., et al.
(författare)
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Preparation and certification of ERM-AE670, a 202Hg enriched methylmercury isotopic reference material
- 2004
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Ingår i: JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY. - : Royal Society of Chemistry (RSC). - 0267-9477. ; 19:10, s. 1315-24
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Tidskriftsartikel (refereegranskat)abstract
- The need for comparability of methylmercury, noted MeHg, measurement results and for the reduction of their associated uncertainties is hampered by the lack of suitable calibration materials. An isotopic certified reference material, ICRM, of MeHg containing isotopically enriched Hg has the potential to answer these problems, in combination with the isotope dilution mass spectrometry, IDMS, strategy. The objective of this work was to produce such a material, of demonstrated stability and carrying certified values traceable to the SI accompanied by combined uncertainty statements. Mercury oxide enriched in 202Hg was used for the preparation of a solution of 202Hg enriched CH3HgCl. The starting material had previously been employed for the preparation of ERM-AE640; a 202Hg enriched inorganic mercury ICRM. The CH3HgCl was synthesised by reaction with a Grignard reagent and a subsequent comproportionation reaction between (CH3)2Hg and HgCl2. The process was optimised to give a high yield of the product, minimise contamination with naturalHg and additional steps were applied to purify the material from other Hg species and by-products of the synthesis reaction. Aliquots of 5 g of the solution were sealed in quartz ampoules for later distribution as a reference material, named ERM-AE670. Using gas chromatography inductively coupled plasma mass spectrometry, only MeHg and inorganic Hg was detectable in the finished reference material with inorganic Hg in <2% of the total amount. The isotopic composition of Hg in the form of MeHg was confirmed to be identical to that of ERM-AE640, within enlarged uncertainty statements. The Hg amount content in the form of MeHg was obtained by subtraction of the inorganic Hg amount content from the total Hg amount content (determined by IDMS in the digested material). The final uncertainty on the Hg amount content in the form of MeHg (3.5% relative, k= 2) included a contribution covering for potential changes over 2 years of shelf-life. This contribution was estimated from the results of a 1 year isochronous stability study.
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