| Records |
| Author |
Trashin, S.; Morales-Yánez, F.; Thiruvottriyur Shanmugam, S.; Paredis, L.; Carrión, E.N.; Sariego, I.; Muyldermans, S.; Polman, K.; Gorun, S.M.; De Wael, K. |
| Title |
Nanobody-based immunosensor detection enhanced by photocatalytic-electrochemical redox cycling |
Type |
A1 Journal article |
| Year |
2021 |
Publication |
Analytical Chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
93 |
Issue  |
40 |
Pages |
13606-13614 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab) |
| Abstract |
Detection of antigenic biomarkers present in trace amounts is of crucial importance for medical diagnosis. A parasitic disease, human toxocariasis, lacks an adequate diagnostic method despite its worldwide occurrence. The currently used serology tests may stay positive even years after a possibly unnoticed infection, whereas the direct detection of a re-infection or a still active infection remains a diagnostic challenge due to the low concentration of circulating parasitic antigens. We report a time-efficient sandwich immunosensor using small recombinant single-domain antibodies (nanobodies) derived from camelid heavy-chain antibodies specific to Toxocara canis antigens. An enhanced sensitivity to pg/mL levels is achieved by using a redox cycle consisting of a photocatalytic oxidation and electrochemical reduction steps. The photocatalytic oxidation is achieved by a photosensitizer generating singlet oxygen (1O2) that, in turn, readily reacts with p-nitrophenol enzymatically produced under alkaline conditions. The photooxidation produces benzoquinone that is electrochemically reduced to hydroquinone, generating an amperometric response. The light-driven process could be easily separated from the background, thus making amperometric detection more reliable. The proposed method for detection of the toxocariasis antigen marker shows superior performances compared to other detection schemes with the same nanobodies and outperforms by at least two orders of magnitude the assays based on regular antibodies, thus suggesting new opportunities for electrochemical immunoassays of challenging low levels of antigens. |
| Address |
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| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000708550500025 |
Publication Date |
2021-09-29 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
6.32 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 6.32 |
| Call Number |
UA @ admin @ c:irua:181795 |
Serial |
8290 |
| Permanent link to this record |
| |
|
| |
| Author |
Alvarez-Martin, A.; Newsome, G.A.; Janssens, K. |
| Title |
High-resolution mass spectrometry and nontraditional mass defect analysis of brominated historical pigments |
Type |
A1 Journal article |
| Year |
2021 |
Publication |
Analytical Chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
93 |
Issue |
44 |
Pages |
14851-14858 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp X-ray Imaging and Spectroscopy (AXIS) |
| Abstract |
The implementation of high-resolution mass spectrometry systems offers new possibilities for the analysis of complex art samples such as historical oil paintings. However, these multicomponent systems generate large and complex data sets that require advanced visualization tools to aid interpretation, especially when no chromatographic separation is performed. In the context of this research, it was crucial to propose a data analysis tool to identify the products generated during the synthesis, drying, and aging of historical pigments. This study reports for the first time a nontraditional mass defect analysis of oil paint samples containing a fugitive brominated-organic pigment, eosin or geranium lake, by using direct infusion electrospray ionization in combination with a high-resolution Orbitrap mass spectrometer. The use of nontraditional Kendrick mass defect plots is presented in this study as a processing and visualization tool to recognize brominated species based on their specific mass defect and isotope pattern. The results demonstrate that this approach could provide valuable molecular compositional information on the degradation pathways of this pigment. We anticipate that mass defect analysis will become highly relevant in future degradation studies of many more historical organic pigments. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000718171600037 |
Publication Date |
2021-10-29 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
6.32 |
Times cited |
|
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 6.32 |
| Call Number |
UA @ admin @ c:irua:182347 |
Serial |
8038 |
| Permanent link to this record |
| |
|
| |
| Author |
Alvarez-Martin, A.; Quanico, J.; Scovacricchi, T.; Avranovich Clerici, E.; Baggerman, G.; Janssens, K. |
| Title |
Chemical mapping of the degradation of geranium lake in paint cross sections by MALDI-MSI |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
95 |
Issue |
49 |
Pages |
18215-18223 |
| Keywords |
A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS); Ecosphere |
| Abstract |
Matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has become a powerful method to extract spatially resolved chemical information in complex materials. This study provides the first use of MALDI-MSI to define spatial–temporal changes in oil paints. Due to the highly heterogeneous nature of oil paints, the sample preparation had to be optimized to prevent molecules from delocalizing. Here, we present a new protocol for the layer-specific analysis of oil paint cross sections achieving a lateral resolution of 10 μm and without losing ionization efficiency due to topographic effects. The efficacy of this method was investigated in oil paint samples containing a mixture of two historic organic pigments, geranium lake and lead white, a mixture often employed in the work of painter Vincent Van Gogh. This methodology not only allows for spatial visualization of the molecules responsible for the pink hue of the paint but also helps to elucidate the chemical changes behind the discoloration of paintings with this composition. The results demonstrate that this approach provides valuable molecular compositional information about the degradation pathways of pigments in specific paint layers and their interaction with the binding medium and other paint components and with light over time. Since a spatial correlation between molecular species and the visual pattern of the discoloration pattern can be made, we expect that mass spectrometry imaging will become highly relevant in future degradation studies of many more historical pigments and paints. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
|
Editor |
|
| Language |
|
Wos |
001142876000001 |
Publication Date |
2023-11-23 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
7.4 |
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 7.4; 2023 IF: 6.32 |
| Call Number |
UA @ admin @ c:irua:201644 |
Serial |
9007 |
| Permanent link to this record |
| |
|
| |
| Author |
Markowicz, A.A.; Van Grieken, R.E. |
| Title |
X-ray spectrometry |
Type |
A1 Journal article |
| Year |
1986 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
58 |
Issue |
5 |
Pages |
279r-294r |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
|
Publication Date |
2005-03-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:116523 |
Serial |
8781 |
| Permanent link to this record |
| |
|
| |
| Author |
Johansson, T.B.; Van Grieken, R.E.; Nelson, J.W.; Winchester, J.W. |
| Title |
Elemental trace analysis of small samples by proton-induced X-ray-emission |
Type |
A1 Journal article |
| Year |
1975 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
47 |
Issue |
6 |
Pages |
855-860 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
A1975AA02900016 |
Publication Date |
2005-03-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:113638 |
Serial |
7895 |
| Permanent link to this record |
| |
|
| |
| Author |
Newsome, G.A.; Kavich, G.; Alvarez-Martin, A. |
| Title |
Interface for reproducible, multishot direct analysis of solid-phase microextraction samples |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Analytical Chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
92 |
Issue |
6 |
Pages |
4182-4186 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
An enclosed interface that joins a direct analysis in real time (DART) probe, solid-phase microextraction (SPME) fiber, and the inlet of a high-resolution mass spectrometer is described. Unlike other systems to couple SPME sampling to ambient mass spectrometry, the interface is able to perform discrete analyses on different areas of a single SPME fiber device for up to three technical replicate measurements of one sampling event. Inlet flow speed and desorption temperature are optimized, and reproducibility is demonstrated between replicate analyses on the same derivatized SPME fiber and with sequential fiber sampling events, yielding analyte measurement center of variance (CV) from 3 to 6%. Conditioning is also performed with the enclosed DART. The interface is a straightforward addition to commercially available technologies, and machine diagrams for custom components operated with SPME/DART/MS equipment are included. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000526563900004 |
Publication Date |
2020-02-07 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
7.4 |
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 7.4; 2020 IF: 6.32 |
| Call Number |
UA @ admin @ c:irua:181926 |
Serial |
8113 |
| Permanent link to this record |
| |
|
| |
| Author |
Bruynseels, F.J.; Van Grieken, R.E. |
| Title |
Laser microprobe mass spectrometric identification of sulfur species in single micrometer-size particles |
Type |
A1 Journal article |
| Year |
1984 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
56 |
Issue |
6 |
Pages |
871-873 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
A1984SP09600012 |
Publication Date |
2005-03-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:116521 |
Serial |
8163 |
| Permanent link to this record |
| |
|
| |
| Author |
van der Snickt, G.; Dik, J.; Cotte, M.; Janssens, K.; Jaroszewicz, J.; de Nolf, W.; Groenewegen, J.; van der Loeff, L. |
| Title |
Characterization of a degraded cadmium yellow (CdS) pigment in an oil painting by means of synchrotron radiation based X-ray techniques |
Type |
A1 Journal article |
| Year |
2009 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
81 |
Issue |
7 |
Pages |
2600-2610 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
On several paintings of James Ensor (1860−1949), a gradual fading of originally bright yellow areas, painted with the pigment cadmium yellow (CdS), is observed. Additionally, in some areas exposed to light, the formation of small white-colored globules on top of the original paint surface is observed. In this paper the chemical transformation leading to the color change and to the formation of the globules is elucidated. Microscopic X-ray absorption near-edge spectroscopy (ì-XANES) experiments show that sulfur, originally present in sulfidic form (S2−), is oxidized during the transformation to the sulfate form (S6+). Upon formation (at or immediately below the surface), the highly soluble cadmium sulfate is assumed to be transported to the surface in solution and reprecipitates there, forming the whitish globules. The presence of cadmium sulfate (CdSO4·2H2O) and ammonium cadmium sulfate [(NH4)2Cd(SO4)2] at the surface is confirmed by microscopic X-ray diffraction measurements, where the latter salt is suspected to result from a secondary reaction of cadmium sulfate with ammonia. Measurements performed on cross sections reveal that the oxidation front has penetrated into the yellow paint down to ca. 1−2 ìm. The morphology and elemental distribution of the paint and degradation product were examined by means of scanning electron microscopy equipped with an energy-dispersive spectrometer (SEM-EDS) and synchrotron radiation based micro-X-ray fluorescence spectrometry (SR ì-XRF). In addition, ultraviolet-induced visible fluorescence photography (UIVFP) revealed itself to be a straightforward technique for documenting the occurrence of this specific kind of degradation on a macroscale by painting conservators. |
| Address |
|
| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
|
| Language |
|
Wos |
000264759400025 |
Publication Date |
2009-03-11 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
6.32 |
Times cited |
91 |
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 6.32; 2009 IF: 5.214 |
| Call Number |
UA @ admin @ c:irua:76415 |
Serial |
5501 |
| Permanent link to this record |
| |
|
| |
| Author |
Rouchon, V.; Duranton, M.; Burgaud, C.; Pellizzi, E.; Lavédrine, B.; Janssens, K.; de Nolf, W.; Nuyts, G.; Vanmeert, F.; Hellemans, K. |
| Title |
Room-temperature study of iron gall ink impregnated paper degradation under various oxygen and humidity conditions : time-dependent monitoring by viscosity and X-ray absorption near-edge spectrometry measurements |
Type |
A1 Journal article |
| Year |
2011 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
83 |
Issue |
7 |
Pages |
2589-2597 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
Many western manuscripts were written using iron gall inks. These inks can damage the paper via two major mechanisms: (a) acid hydrolysis, enhanced by humidity, and (b) oxidative depolymerization provoked by the presence of oxygen and free iron(II) ions. The degradation of unsized Whatman paper impregnated with different combinations of iron sulfate, gallic acid, and gum arabic was studied at room temperature in order to assess the relative importance of each mechanism. The samples were stored in various environments including a dry and/or an oxygen-free atmosphere. The cellulose depolymerization was monitored by viscometry and related to changes in the oxidation state of iron, determined by X-ray absorption near-edge spectrometry. The results indicate that residual amounts of oxygen (less than 0.1%) promote cellulose depolymerization, whereas the level of relative humidity has no impact. The cellulose depolymerization also appears closely correlated to oxidative mechanisms. Regarding the oxidation of iron, it only occurs in the simultaneous presence of oxygen and moisture, suggesting the occurrence of rustlike oxidative mechanisms. Finally, the presence of gallic acid has a strong influence, which is only partially explained by its capacity to reduce iron(III) to iron(II). |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000288887700028 |
Publication Date |
2011-03-04 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
6.32 |
Times cited |
28 |
Open Access |
|
| Notes |
; This research was supported by the French Ministry of Culture within the National Program of Research (“La conservation des manuscrits: etude du vieillissement naturel de papiers impregnes d'encres ferrogalliques”). It was funded by grants from HASYLAB (experiments I-20090280 EC and II-20060245 EC) and SOLEIL (proposals 20060396 and 20080761) and was supported by the Interuniversity Attraction Poles Programme Belgian Science Policy (1UAP V1/16). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects nos. G.0689.06, G.0704.08 and G017909N. We are thankful to Dr. Dominique Thaudiere, Dr. Solenn Reguer, Dr. Andrea Somogyi, Dr. Karen Appel, Dr. Manuela Borchert, and Dr. Gerald Falkenberg for their assistance and help during the experiments performed at SOLEIL beamline “DIFFABS” and at HASYLAB Beam line “L” respectively. ; |
Approved |
Most recent IF: 6.32; 2011 IF: 5.856 |
| Call Number |
UA @ admin @ c:irua:89593 |
Serial |
5822 |
| Permanent link to this record |
| |
|
| |
| Author |
Markowicz, A.A.; Storms, H.M.; Van Grieken, R.E. |
| Title |
Absorption correction in electron probe x-ray microanalysis of thin samples |
Type |
A1 Journal article |
| Year |
1986 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
58 |
Issue |
7 |
Pages |
1282-1285 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
A1986C594100007 |
Publication Date |
2005-03-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:116524 |
Serial |
7409 |
| Permanent link to this record |
| |
|
| |
| Author |
van Espen, P.; Van 't dack, L.; Adams, F.; Van Grieken, R. |
| Title |
Effective sample weight from scatter peaks in energy-dispersive x-ray fluorescence |
Type |
A1 Journal article |
| Year |
1979 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
51 |
Issue |
7 |
Pages |
961-967 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Chemometrics (Mitac 3) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
A1979GW66100047 |
Publication Date |
2005-03-16 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:111404 |
Serial |
7841 |
| Permanent link to this record |
| |
|
| |
| Author |
Marguí, E.; Fontàs, C.; van Meel, K.; Van Grieken, R.; Queralt, I.; Hidalgo, M. |
| Title |
High-energy polarized-beam energy-dispersive X-ray fluorescence analysis combined with activated thin layers for cadmium determination at trace levels in complex environmental liquid samples |
Type |
A1 Journal article |
| Year |
2008 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
80 |
Issue |
7 |
Pages |
2357-2364 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000254593500015 |
Publication Date |
2008-03-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:68425 |
Serial |
8032 |
| Permanent link to this record |
| |
|
| |
| Author |
Ma, X.; Pavlidis, G.; Dillon, E.; Beltran, V.; Schwartz, J.J.; Thoury, M.; Borondics, F.; Sandt, C.; Kjoller, K.; Berrie, B.H.; Centrone, A. |
| Title |
Micro to nano : multiscale IR analyses reveal zinc soap heterogeneity in a 19th-century painting by Corot |
Type |
A1 Journal article |
| Year |
2022 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
94 |
Issue |
7 |
Pages |
3103-3110 |
| Keywords |
A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab) |
| Abstract |
Formation and aggregation of metal carboxylates (metal soaps) can degrade the appearance and integrity of oil paints, challenging efforts to conserve painted works of art. Endeavors to understand the root cause of metal soap formation have been hampered by the limited spatial resolution of Fourier transform infrared microscopy (mu-FTIR). We overcome this limitation using optical photothermal infrared spectroscopy (O-PTIR) and photothermal-induced resonance (PTIR), two novel methods that provide IR spectra with approximate to 500 and approximate to 10 nm spatial resolutions, respectively. The distribution of chemical phases in thin sections from the top layer of a 19th-century painting is investigated at multiple scales (mu-FTIR approximate to 10(2) mu m(3), O-PTIR approximate to 10(-1) mu m(3), PTIR approximate to 10(-5) mu m(3)). The paint samples analyzed here are found to be mixtures of pigments (cobalt green, lead white), cured oil, and a rich array of intermixed, small (often << 0.1 mu m(3)) zinc soap domains. We identify Zn stearate and Zn oleate crystalline soaps with characteristic narrow IR peaks (approximate to 1530-1558 cm(-1)) and a heterogeneous, disordered, water-permeable, tetrahedral zinc soap phase, with a characteristic broad peak centered at approximate to 1596 cm(-1). We show that the high signal-to-noise ratio and spatial resolution afforded by O-PTIR are ideal for identifying phase-separated (or locally concentrated) species with low average concentration, while PTIR provides an unprecedented nanoscale view of distributions and associations of species in paint. This newly accessible nanocompositional information will advance our knowledge of chemical processes in oil paint and will stimulate new art conservation practices. |
| Address |
|
| Corporate Author |
|
Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000766206700011 |
Publication Date |
2022-02-09 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
OpenAccess |
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:187380 |
Serial |
8897 |
| Permanent link to this record |
| |
|
| |
| Author |
De Jong, M.; Florea, A.; de Vries, A.-M.; van Nuijs, A.L.N.; Covaci, A.; Van Durme, F.; Martins, J.C.; Samyn, N.; De Wael, K. |
| Title |
Levamisole : a common adulterant in cocaine street samples hindering electrochemical detection of cocaine |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
90 |
Issue |
8 |
Pages |
5290-5297 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre |
| Abstract |
The present work investigates the electrochemical determination of cocaine in the presence of levamisole, one of the most common adulterants found in cocaine street samples. Levamisole misleads cocaine color tests, giving a blue color (positive test) even in the absence of cocaine. Moreover, the electrochemical detection of cocaine is also affected by the presence of levamisole, with a suppression of the oxidation signal of cocaine. When levamisole is present in the sample in ratios higher than 1:1, the cocaine signal is no longer detected, thus leading to false negative results. Mass spectrometry and nuclear magnetic resonance were used to investigate if the signal suppression is due to the formation of a complex between cocaine and levamisole in bulk solution. Strategies to eliminate this suppressing effect are further suggested in this manuscript. In a first approach, the increase of the pH of the sample solution from pH 7 to pH 12 allowed the voltammetric determination of cocaine in the presence of levamisole in a concentration range from 10 to 5000 μM at nonmodified graphite disposable electrodes with a detection limit of 5 μM. In a second approach, the graphite electrode was cathodically pretreated, resulting in the presence of oxidation peaks of both cocaine and levamisole, with a detection limit for cocaine of 3 μM over the linear range of concentrations from 10 to 2500 μM. Both these strategies have been successfully applied for the simultaneous detection of cocaine and levamisole in three street samples on unmodified graphite disposable electrodes. |
| Address |
|
| Corporate Author |
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Thesis |
|
| Publisher |
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Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000430512200049 |
Publication Date |
2018-02-23 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
6.32 |
Times cited |
8 |
Open Access |
|
| Notes |
; This project has received funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement No. 753223 Narcoreader. This work was also supported by BR/314/PI/ APTADRU Project and IOF-SBO (UAntwerp). Alexander van Nuijs acknowledges the Research Foundation-Flanders (FWO) for his postdoctoral fellowship. ; |
Approved |
Most recent IF: 6.32 |
| Call Number |
UA @ admin @ c:irua:149528 |
Serial |
5693 |
| Permanent link to this record |
| |
|
| |
| Author |
Ro, C.-U.; Osán, J.; Van Grieken, R. |
| Title |
Determination of low-Z elements in individual environmental particles using windowless EPMA |
Type |
A1 Journal article |
| Year |
1999 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
71 |
Issue |
8 |
Pages |
1521-1528 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
|
| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
|
| Language |
|
Wos |
000079756900007 |
Publication Date |
2002-07-26 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:23185 |
Serial |
7782 |
| Permanent link to this record |
| |
|
| |
| Author |
Verbueken, A.H.; Van Grieken, R.E.; Paulus, G.J.; De Bruijn, W.C. |
| Title |
Embedded ion exchange beads as standards for laser microprobe mass analysis of biological specimens |
Type |
A1 Journal article |
| Year |
1984 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
56 |
Issue |
8 |
Pages |
1362-1370 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
|
| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
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Editor |
|
| Language |
|
Wos |
A1984SX51800045 |
Publication Date |
2005-03-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:116520 |
Serial |
7898 |
| Permanent link to this record |
| |
|
| |
| Author |
Van Dyck, P.M.; Török, S.B.; Van Grieken, R.E. |
| Title |
Enhancement effect in X-ray fluorescence analysis of environmental samples of medium thickness |
Type |
A1 Journal article |
| Year |
1986 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
58 |
Issue |
8 |
Pages |
1761-1766 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
A1986C955500040 |
Publication Date |
2005-03-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:116522 |
Serial |
7915 |
| Permanent link to this record |
| |
|
| |
| Author |
Aghaei, M.; Lindner, H.; Bogaerts, A. |
| Title |
Ion Clouds in the Inductively Coupled Plasma Torch: A Closer Look through Computations |
Type |
A1 Journal article |
| Year |
2016 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
88 |
Issue |
88 |
Pages |
8005-8018 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
We have computationally investigated the introduction of copper elemental particles in an inductively coupled plasma torch connected to a sampling cone, including for the first time the ionization of the sample. The sample is inserted as liquid particles, which are followed inside the entire torch, i.e., from the injector inlet up to the ionization and reaching the sampler. The spatial position of the ion clouds inside the torch as well as detailed information on the copper species fluxes at the position of the sampler orifice and the exhausts of the torch are provided. The effect of on- and off-axis injection is studied. We clearly show that the ion clouds of on-axis injected material are located closer to the sampler with less radial diffusion. This guarantees a higher transport efficiency through the sampler cone. Moreover, our model reveals the optimum ranges of applied power and flow rates, which ensure the proper position of ion clouds inside the torch, i.e., close enough to the sampler to increase the fraction that can enter the mass spectrometer and with minimum loss of material toward the exhausts as well as a sufficiently high plasma temperature for efficient ionization. |
| Address |
Research Group PLASMANT, Chemistry Department, University of Antwerp , Universiteitsplein 1, 2610 Antwerp, Belgium |
| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
English |
Wos |
000381654800020 |
Publication Date |
2016-07-26 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
6.32 |
Times cited |
9 |
Open Access |
|
| Notes |
The authors gratefully acknowledge financial support from the Fonds voor Wetenschappelijk Onderzoek (FWO), Grant Number 6713. The computational work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the UA. |
Approved |
Most recent IF: 6.32 |
| Call Number |
PLASMANT @ plasmant @ c:irua:135644 |
Serial |
4293 |
| Permanent link to this record |
| |
|
| |
| Author |
Rahemi, V.; Sarmadian, N.; Anaf, W.; Janssens, K.; Lamoen, D.; Partoens, B.; De Wael, K. |
| Title |
Unique opto-electronic structure and photo reduction properties of sulfur doped lead chromates explaining their instability in paintings |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
89 |
Issue |
89 |
Pages |
3326-3334 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
Chrome yellow refers to a group of synthetic inorganic pigments that became popular as an artists material from the second quarter of the 19th century. The color of the pigment, in which the chromate ion acts as a chromophore, is related to its chemical composition (PbCr1-xSxO4, with 0≤x≤0.8) and crystalline structure (monoclinic/orthorhombic). Their shades range from the yellow-orange to the paler yellow tones with increasing sulfate amount. These pigments show remarkable signs of degradation after limited time periods. Pure PbCrO4 (crocoite in its natural form) has a deep yellow color and is relatively stable, while the co-precipitate with lead sulfate (PbCr1-xSxO4) has a paler shade and seems to degrade faster. This degradation is assumed to be related to the reduction of Cr(VI) to Cr(III). We show that on increasing the sulfur(S)-content in chrome yellow, the band gap increases. Typically, when increasing the band gap, one might assume that a decrease in photo activity is the result. However, the photo activity relative to the Cr content, and thus Cr reduction, of sulfur-rich PbCr1-xSxO4 is found to be much higher compared to the sulfur-poor or non-doped lead chromates. This discrepancy can be explained by the evolution of the crystal and electronic structure as function of the sulfur content: first-principles density functional theory calculations show that both the absorption coefficient and reflection coefficients of the lead chromates change as a result of the sulfate doping in such a way that the generation of electron-hole pairs under illumination relative to the total Cr content increases. These changes in the material properties explain why paler shade yellow colors of this pigment are more prone to discoloration. The electronic structure calculations also demonstrate that lead chromate and its co-precipitates are p-type semiconductors, which explains the observed reduction reaction. As understanding this phenomenon is valuable in the field of cultural heritage, this study is the first joint action of photo-electrochemical measurements and first-principles calculations to approve the higher tendency of sulfur-rich lead chromates to darken. |
| Address |
|
| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
| Language |
|
Wos |
000397478300015 |
Publication Date |
2017-02-23 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
6.32 |
Times cited |
7 |
Open Access |
OpenAccess |
| Notes |
; The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the Hercules Foundation and the Flemish Government, department EWI. The BOF-GOA action SOLARPAINT of the University of Antwerp Research Council is acknowledged for financial support. W.A. acknowledges support from BELSPO project S2-ART. Dr. L. Monico and Dr. C. Miliani (ISTM, Perugia) are gratefully acknowledged for helpful discussions and for providing some of the initial batches of the materials studied. ; |
Approved |
Most recent IF: 6.32 |
| Call Number |
UA @ lucian @ c:irua:140886 |
Serial |
4451 |
| Permanent link to this record |
| |
|
| |
| Author |
Smits, J.A.; Van Grieken, R.E. |
| Title |
Characterization of a 2,2'-diaminodiethylamine-cellulose filter toward metal cation extraction |
Type |
A1 Journal article |
| Year |
1980 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
52 |
Issue |
9 |
Pages |
1479-1489 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
A1980KB79500027 |
Publication Date |
2005-03-08 |
| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:116515 |
Serial |
7610 |
| Permanent link to this record |
| |
|
| |
| Author |
Van Grieken, R.E.; Bresseleers, C.M.; Vanderborght, B.M. |
| Title |
Chelex-100 ion-exchange filter membranes for preconcentration in x-ray-fluorescence analysis of water |
Type |
A1 Journal article |
| Year |
1977 |
Publication |
Analytical chemistry |
Abbreviated Journal |
|
| Volume |
49 |
Issue |
9 |
Pages |
1326-1331 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
|
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
|
Wos |
A1977DP25600011 |
Publication Date |
2005-03-08 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:113632 |
Serial |
7639 |
| Permanent link to this record |
| |
|
| |
| Author |
Rahemi, V.; Trashin, S.; Hafideddine, Z.; Van Doorslaer, S.; Meynen, V.; Gorton, L.; De Wael, K. |
| Title |
Amperometric flow-injection analysis of phenols induced by reactive oxygen species generated under daylight irradiation of titania impregnated with horseradish peroxidase |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Analytical Chemistry |
Abbreviated Journal |
Anal Chem |
| Volume |
92 |
Issue |
92 |
Pages |
3643-3649 |
| Keywords |
A1 Journal article; Laboratory of adsorption and catalysis (LADCA); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
Titanium dioxide (TiO2) is a unique material for biosensing applications due to its capability of hosting enzymes. For the first time, we show that TiO2 can accumulate reactive oxygen species (ROS) under daylight irradiation and can support the catalytic cycle of horseradish peroxidase (HRP) without the need of H2O2 to be present in the solution. Phenolic compounds, such as hydroquinone (HQ) and 4-aminophenol (4-AP), were detected amperometrically in flow-injection analysis (FIA) mode via the use of an electrode modified with TiO2 impregnated with HRP. In contrast to the conventional detection scheme, no H2O2 was added to the analyte solution. Basically, the inherited ability of TiO2 to generate reactive oxygen species is used as a strategy to avoid adding H2O2 in the solution during the detection of phenolic compounds. Electron paramagnetic resonance (EPR) spectroscopy indicates the presence of ROS on titania which, in interaction with HRP, initiate the electrocatalysis toward phenolic compounds. The amperometric response to 4-AP was linear in the concentration range between 0.05 and 2 μM. The sensitivity was 0.51 A M–1 cm–2, and the limit of detection (LOD) 26 nM. The proposed sensor design opens new opportunities for the detection of phenolic traces by HRP-based electrochemical biosensors, yet in a more straightforward and sensitive way following green chemistry principles of avoiding the use of reactive and harmful chemical, such as H2O2. |
| Address |
|
| Corporate Author |
|
Thesis |
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| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000518234700023 |
Publication Date |
2020-01-27 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
7.4 |
Times cited |
3 |
Open Access |
|
| Notes |
; The authors thank Scientific Reseatch-Flanders (F-WO) (grant 12T4219N) for funding. ; |
Approved |
Most recent IF: 7.4; 2020 IF: 6.32 |
| Call Number |
UA @ admin @ c:irua:166241 |
Serial |
5463 |
| Permanent link to this record |
