| 11. |
- González Baró, Ana, et al.
(författare)
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Speciation in the aqueous peroxovanadate-maltol and (peroxo)vanadate-uridine systems
- 2008
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 8, s. 1095-102
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Tidskriftsartikel (refereegranskat)abstract
- The speciation in the aqueous H+/H2VO4-/H2O2/maltol (Ma), H+/H2VO4-/uridine (Ur) and H+/H2VO4-/H2O2/Ur systems was determined in the physiological medium of 0.150 M Na(Cl) at 25 °C. A combination of quantitative 51V NMR (Bruker AMX500) and potentiometric data (glass electrode) was collected and treated simultaneously by the computer program LAKE. In the quaternary maltol system, the two species VXMa2- and VX2Ma2- (where X denotes the peroxo ligand) were found in the pH region 5-10, in addition to all binary and ternary complexes. Their formation was fast. In the ternary uridine (H+/H2VO4-/Ur) subsystem, altogether three vanadate-uridine (V-Ur) species were found in the pH region 4-10, with compositions VUr2-, V2Ur22- and V2Ur23-. Equilibrium was fast except in weakly acidic solutions when slowly decomposing decavanadates formed. In the quaternary H+/H2VO4-/H2O2/Ur system, five additional species were found at pH > 7. They were of VXUr and VX2Ur compositions. Their formation was fast. Formation constants, compositions and 51V NMR chemical shifts are given for all the species found in the systems, and equilibrium conditions are illustrated in distribution diagrams as well as the fit of the model to the experimental data. Biological and medical relevance of the species (in the treatment of diabetes) are also discussed, with pseudo-physiological conditions modelled.
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| 12. |
- Gorzsás, András, et al.
(författare)
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A speciation study of the aqueous H+/H2VO4–/H2O2/L--alanyl-L-serine system
- 2003
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; , s. 1161-7
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Tidskriftsartikel (refereegranskat)abstract
- A detailed study of the quaternary aqueous H+/H2VO4–/H2O2/L--alanyl-L-serine (Alaser) system has been performed at 25 °C in 0.150 M Na(Cl) medium, representing the ionic strength of human blood, using quantitative 51V NMR and potentiometric data (glass electrode). Data were evaluated with the computer program LAKE, which is able to treat combined EMF and NMR data. The pKa-values for Alaser were determined as 8.04 ± 0.01 and 3.07 ± 0.01. The errors given are 3. In the ternary H+/H2VO4–/Alaser system, two complexes, (H+)p(H2VO4–)q(Alaser)r, having (p, q, r) values (0, 1, 1) and (–1, 1, 1) with log0,1,1= 2.42 ± 0.01 and log–1,1,1=–5.80 ± 0.05 explain all data in the pH region 2.5–9.5. Equilibrium conditions are illustrated in distribution diagrams and structure proposals are given based on 1H and 13C NMR investigations. In the quaternary H+/H2VO4–/H2O2/Alaser system, six complexes could be found in addition to all binary and ternary complexes over the pH region 2.6–11.1, four with a V/X/Alaser ratio 1 1 1 and two with a ratio 1 2 1 (X = peroxo ligand). The formation of the monoperoxo vanadium species is very slow, requiring up to 10 days for complete equilibrium. Significant decomposition of peroxide occurs only in acidic solutions. Chemical shifts, compositions and formation constants for the six quaternary complexes are given, and equilibrium conditions are illustrated in distribution diagrams. The H+/H2VO4–/H2O2/Alaser/Alahis system, where Alahis denotes L--alanyl-L-histidine, was briefly investigated and no mixed ligand species were detected.
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| 13. |
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| 14. |
- Gorzsás, András, et al.
(författare)
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Cell specific chemotyping and multivariate imaging by combined FT-IR microspectroscopy and OPLS analysis reveals the chemical landscape of secondary xylem
- 2011
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Ingår i: The Plant Journal. - : Blackwell Publishing Ltd. - 0960-7412 .- 1365-313X. ; 66:5, s. 903-914
-
Tidskriftsartikel (refereegranskat)abstract
- Fourier-transform infrared (FT-IR) spectroscopy combined with microscopy enables acquiring chemical information from native plant cell walls with high spatial resolution. Combined with a 64 x 64 focal plane array (FPA) detector 4096 spectra from a 0.3 x 0.3 mm image can be simultaneously obtained, where each spectrum represents a compositional and structural "fingerprint" of all cell wall components. For optimal use and analysis of such large amount of information, multivariate approaches are preferred. Here, FT-IR microspectroscopy with FPA detection is combined with orthogonal projections to latent structures discriminant analysis (OPLS-DA). This allows for 1) the extraction of spectra from specific cell types, 2) identification and characterization of different chemotypes using the full spectral information, and 3) further visualising the pattern of identified chemotypes by multivariate imaging. As proof of concept, the chemotypes of Populus tremula xylem cell types are described. The approach revealed unknown features about chemical plasticity and patterns of lignin composition in wood fibers that would have remained hidden in the dataset with traditional data analysis. The applicability of the method on Arabidopsis xylem, and its usefulness in mutant chemotyping is also demonstrated. The methodological approach is not limited to xylem tissues but can be applied to any plant organ/tissue also using other microspectroscopy techniques such as Raman- and UV-microspectroscopy.
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| 15. |
- Gorzsas, Andras, et al.
(författare)
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Cell-specific chemotyping and multivariate imaging by combined FT-IR microspectroscopy and orthogonal projections to latent structures (OPLS) analysis reveals the chemical landscape of secondary xylem
- 2011
-
Ingår i: Plant Journal. - 0960-7412 .- 1365-313X. ; 66, s. 903-914
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Tidskriftsartikel (refereegranskat)abstract
- P>Fourier-transform infrared (FT-IR) spectroscopy combined with microscopy enables chemical information to be acquired from native plant cell walls with high spatial resolution. Combined with a 64 x 64 focal plane array (FPA) detector, 4096 spectra can be simultaneously obtained from a 0.3 x 0.3 mm image; each spectrum represents a compositional and structural 'fingerprint' of all cell wall components. For optimal use and analysis of such a large amount of information, multivariate approaches are preferred. Here, FT-IR microspectroscopy with FPA detection is combined with orthogonal projections to latent structures discriminant analysis (OPLS-DA). This allows for: (i) the extraction of spectra from single cell types, (ii) identification and characterization of different chemotypes using the full spectral information, and (iii) further visualization of the pattern of identified chemotypes by multivariate imaging. As proof of concept, the chemotypes of Populus tremula xylem cell types are described. The approach revealed unknown features about chemical plasticity and patterns of lignin composition in wood fibers that would have remained hidden in the dataset with traditional data analysis. The applicability of the method to Arabidopsis xylem and its usefulness in mutant chemotyping is also demonstrated. The methodological approach is not limited to xylem tissues but can be applied to any plant organ/tissue also using other techniques such as Raman and UV microspectroscopy.
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| 16. |
- Gorzsas, Andras
(författare)
-
Characterization of dissolving pulp by multivariate data analysis of FT-IR and NMR spectra
- 2011
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Ingår i: Nordic Pulp and Paper Research Journal. - 0283-2631 .- 2000-0669. ; 26, s. 398-409
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Tidskriftsartikel (refereegranskat)abstract
- Many common, yet expensive and time consuming, pulp analyses could also be predicted by the achieved models. It can be concluded that investigations of dissolving pulp characteristics, especially concerning different wood and process types, can take advantage of the methods and models presented in this study.
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| 17. |
- Gorzsás, András, et al.
(författare)
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Chemical fingerprinting of arabidopsis using fourier transform infrared (FT-IR) spectroscopic approaches
- 2014. - 3
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Ingår i: Arabidopsis protocols. - Totowa, NJ : Humana Press. - 9781627035798 - 9781493962761 - 9781627035804 ; , s. 317-352
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Bokkapitel (refereegranskat)abstract
- Fourier transform infrared (FT-IR) spectroscopy is a fast, sensitive, inexpensive, and nondestructive technique for chemical profiling of plant materials. In this chapter we discuss the instrumental setup, the basic principles of analysis, and the possibilities for and limitations of obtaining qualitative and semiquantitative information by FT-IR spectroscopy. We provide detailed protocols for four fully customizable techniques: (1) Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS): a sensitive and high-throughput technique for powders; (2) attenuated total reflectance (ATR) spectroscopy: a technique that requires no sample preparation and can be used for solid samples as well as for cell cultures; (3) microspectroscopy using a single element (SE) detector: a technique used for analyzing sections at low spatial resolution; and (4) microspectroscopy using a focal plane array (FPA) detector: a technique for rapid chemical profiling of plant sections at cellular resolution. Sample preparation, measurement, and data analysis steps are listed for each of the techniques to help the user collect the best quality spectra and prepare them for subsequent multivariate analysis.
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| 18. |
- Gorzsás, András
(författare)
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Chemical imaging of xylem by Raman microspectroscopy
- 2017. - 1
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Ingår i: Xylem. - New York : Humana Press. - 9781493967209 - 9781493967223 ; , s. 133-178
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Bokkapitel (refereegranskat)abstract
- Raman microspectroscopic techniques provide highly detailed chemical information about xylem tissue at submicron spatial resolution. The techniques are generally sensitive and they provide a powerful, yet inexpensive way to probe the chemical composition of individual cells or cell wall layers in situ, non-destructively, in a confocal manner, simultaneously detecting all chemical compounds without the need of external agents (label, dyes, stains). Problems with limited specificity in complex chemical matrices such as cell walls may arise, compounded by fluorescence problems. However, these can often be circumvented. In this chapter, the basics of the technique, including a common instrumental setup, together with the general strengths and limitations of Raman microspectroscopy are discussed. Detailed protocols are provided for single point measurements, as well as for fully customizable raster scan mapping, including sample preparation, setup, and measurement steps. The major steps of the data analysis procedure are discussed as well.
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| 19. |
- Gorzsás, András, et al.
(författare)
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On the Fate of Vanadate in Human Blood
- 2006
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Ingår i: European Journal of Inorganic Chemistry. - : Wiley. - 1434-1948 .- 1099-0682. ; 18, s. 3559-65
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Tidskriftsartikel (refereegranskat)abstract
- The cover picture shows a symbolic representation of the fate of vanadate in human blood. Since the transition metal vanadium is named after Vanadis, the Nordic goddess of beauty, she is represented by the famous Venus de Milo sculpted in metal. Her cloth is decorated with the functional groups of the ligands that can form a complex (dress) with the metal while travelling in the blood vessels, the latter being symbolised by the caverns in the background. The water in the caves represents the aqueous solutions in which speciation studies have been carried out in the group of Professor Lage Pettersson. Further references to these studies are found as cave paintings on the walls: a distribution diagram and a set of 51V NMR spectra. The studies have been carried out in the framework of the COST D21/009 working group. The geographical locations of the research groups within this working group are shown by illuminated dots on the map of Europe in the background. The goal of the studies was to better understand the ability of vanadium to lower blood glucose levels (represented by the sugar cubes washed ashore on the left) and thus its potential as an orally applicable drug against diabetes. A Microreview, covering the results of the above mentioned speciation studies dealing with the fate of vanadate in human blood, is represented by A. Gorzsás, I. Andersson, and L. Pettersson on p. 3559 ff. The digital artwork for this cover was created by András Gorzsás.
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| 20. |
- Gorzsás, András
(författare)
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Raman microspectroscopy
- 2018
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Ingår i: Encyclopedia of Geochemistry. - Cham : Springer. - 9783319393117 - 9783319393124 ; , s. 1303-1307
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Bokkapitel (refereegranskat)
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