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Irgum, Knut
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Publications (10 of 59) Show all publications
Shamshir, A., Dinh, N. P., Jonsson, T., Sparrman, T., Ashiq, M. J. & Irgum, K. (2019). Interaction of toluene with polar stationary phases under conditions typical of hydrophilic interaction chromatography probed by saturation transfer difference nuclear magnetic resonance spectroscopy. Journal of Chromatography A, 1588, 58-67
Open this publication in new window or tab >>Interaction of toluene with polar stationary phases under conditions typical of hydrophilic interaction chromatography probed by saturation transfer difference nuclear magnetic resonance spectroscopy
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2019 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1588, p. 58-67Article in journal (Refereed) Published
Abstract [en]

Toluene has been used as void volume (zero retention) marker since the inception of hydrophilic interaction chromatography (HILIC), based on the assumption that its hydrophobicity should prevent it from interacting with stationary phases envisioned to be covered by relatively thick layers of water. Recent work has shown that the void volumes of partly water-swollen HILIC phases are not identical to the volumes probed by toluene, yet the compound is still ubiquitously used as void volume marker. As part of our investigations of the retention mechanisms in HILIC, we probed the extent to which toluene is capable of penetrating into the water-enriched layer and to interact with the functional groups of three commercially available hydrophilic and polar stationary phases with different charge properties and water-retaining abilities, using saturation transfer difference 1H nuclear magnetic resonance (STD-NMR) spectroscopy at high resolution magic angle spinning (HR-MAS) conditions. The test solutions were 1000 ppm of toluene in deuterated acetonitrile and water mixtures, with and without addition of ammonium acetate, in order to mimic a set of conditions typically encountered in HILIC separations. Interactions between toluene and the functional groups on the stationary phases were probed by equilibrating the phases with these eluent mimics and measuring the transfer of magnetization from stationary phase protons to the protons of toluene. Our results show that toluene is indeed capable of traversing the water-enriched layers of all the three tested phases and of interacting with protons that are tightly associated with the stationary phases.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-157748 (URN)10.1016/j.chroma.2018.11.028 (DOI)000461403900008 ()30704776 (PubMedID)2-s2.0-85060523282 (Scopus ID)
Available from: 2019-04-09 Created: 2019-04-09 Last updated: 2019-04-09Bibliographically approved
Liu, M., Torsetnes, S. B., Wierzbicka, C., Jensen, O. N., Sellergren, B. & Irgum, K. (2019). Selective Enrichment of Phosphorylated Peptides by Monolithic Polymers Surface Imprinted with bis-Imidazolium Moieties by UV-Initiated Cryopolymerization. Analytical Chemistry, 91(15), 10188-10196
Open this publication in new window or tab >>Selective Enrichment of Phosphorylated Peptides by Monolithic Polymers Surface Imprinted with bis-Imidazolium Moieties by UV-Initiated Cryopolymerization
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2019 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 15, p. 10188-10196Article in journal (Refereed) Published
Abstract [en]

Reversible protein phosphorylation on serine, threonine, and tyrosine residues is essential for fast, specific, and accurate signal transduction in cells. Up to now, the identification and quantification of phosphorylated amino acids, peptides, and proteins continue to be one of the significant challenges in contemporary bioanalytical research. In this paper, a series of surface grafted monoliths in the capillary format targeting phosphorylated serine has been prepared by first synthesizing a monolithic core substrate material based on trimethylolpropane trimethacrylate, onto which a thin surface-imprinted layer was established by oriented photografting of a variety of mono- and bis-imidazolium host monomers at subzero temperature, using six different continuous or pulsed UV light sources. The imprinted monolith capillaries were evaluated in a capillary liquid chromatographic system connected to a mass spectrometer in order to test the specific retention of phosphorylated peptides. Site-specific recognition selectivity and specificity for phosphorylated serine was demonstrated when separating amino acids and peptides, proving that the optimized materials could be used as novel trapping media in affinity-based phosphoproteomic analysis.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-162863 (URN)10.1021/acs.analchem.9b02211 (DOI)000480499200115 ()31283183 (PubMedID)
Available from: 2019-09-05 Created: 2019-09-05 Last updated: 2019-09-05Bibliographically approved
Wierzbicka, C., Liu, M., Bauer, D., Irgum, K. & Sellergren, B. (2017). Cationic pTyr/pSer imprinted polymers based on a bis-imidazolium host monomer: phosphopeptide recognition in aqueous buffers demonstrated by mu-liquid chromatography and monolithic columns. Journal of materials chemistry. B, 5(5), 953-960
Open this publication in new window or tab >>Cationic pTyr/pSer imprinted polymers based on a bis-imidazolium host monomer: phosphopeptide recognition in aqueous buffers demonstrated by mu-liquid chromatography and monolithic columns
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2017 (English)In: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 5, no 5, p. 953-960Article in journal (Refereed) Published
Abstract [en]

We report on the design and characterization of imprinted cationic host polymers for selective trapping of phosphoserine and phosphotyrosine peptides. A series of imidazolium host monomers were synthesized and characterized with respect to binding affinity and stoichiometry of interaction with salts of phenylphosphonic acid. The strongest binders were subsequently used for the preparation of imprinted polymers in the form of crushed monoliths, using Fmoc-phosphotyrosine-ethyl ester or Fmoc-phosphoserine-ethyl ester as templates in combination with a hydrophilic crosslinking monomer. The polymers were compared with respect to binding and its dependence on solvent, and whether charged or uncharged host monomers were used. The recipes were subsequently implemented in the capillary monolith format for evaluation by micro-liquid chromatography in both buffered and organic media. Results from both tested formats reveal that the cationic host polymers displayed enhanced recognition in polar and buffered media, in contrast to neutral urea-based hosts which showed best results in acetonitrile rich mobile phases.

National Category
Polymer Chemistry
Identifiers
urn:nbn:se:umu:diva-133229 (URN)10.1039/c6tb02864k (DOI)000395908000007 ()
Available from: 2017-04-12 Created: 2017-04-12 Last updated: 2018-06-09Bibliographically approved
Liu, M., Tran, T. M., Elhaj, A. A., Torsetnes, S. B., Jensen, O. N., Sellergren, B. & Irgum, K. (2017). Molecularly Imprinted Porous Monolithic Materials from Melamine-Formaldehyde for Selective Trapping of Phosphopeptides. Analytical Chemistry, 89(17), 9491-9501
Open this publication in new window or tab >>Molecularly Imprinted Porous Monolithic Materials from Melamine-Formaldehyde for Selective Trapping of Phosphopeptides
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2017 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 89, no 17, p. 9491-9501Article in journal (Refereed) Published
Abstract [en]

Thirty-five melamine formaldehyde (MF) monolithic materials with bimodal pore distributions were synthesized in fused silica capillaries by catalyst-free polycondensation, starting with an aqueous MF precondensate, using acetonitrile as the macroporogen and a variety of aliphatic polyethers and triblock copolymeric surfactants as porogens and mesoporogens, respectively. By varying the prepolymer composition and the type and molecular weight of the polymeric porogen components, a library of porous monolithic materials was produced, covering a range of meso- and macroporous properties. A multivariate evaluation revealed that the amount of surfactant was the strongest contributor to specific surface area and pore volume and to the inversely related mesopore size, whereas the macropore dimensions were controlled mainly by the amount of aliphatic polyether porogen. One of these capillary monoliths, chosen based on the combination of meso- and macropores providing optimal percolative flow and accessible surface area, was synthesized in the presence of N-Fmoc and O-Et protected phosphoserine and phosphotyrosine to prepare molecularly imprinted monoliths with surface layers selective for phosphopeptides. These imprinted monoliths were characterized alongside nonimprinted monoliths by a variety of techniques and finally evaluated by liquid chromatography mass spectrometry in the capillary format to assess their abilities to trap and release phosphorylated amino acids and peptides from partly aqueous media. Selective enrichment of phosphorylated targets was demonstrated, suggesting that these materials could be useful as trapping media in-affinity-based phosphoproteomics.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
National Category
Polymer Technologies
Identifiers
urn:nbn:se:umu:diva-140044 (URN)10.1021/acs.analchem.7b02470 (DOI)000410014900125 ()28795574 (PubMedID)
Available from: 2017-10-02 Created: 2017-10-02 Last updated: 2018-06-09Bibliographically approved
Basu, B., Paul, S., Kundu, S., Byström, E., Irgum, K. & Almqvist, F. (2017). Organic Polymeric Resins Embedded with Pd NPs: Newly Designed, Efficient and Chemoselective Catalyst for Reduction of Nitrobenzenes. Current Organocatalysis, 4(1), 48-61
Open this publication in new window or tab >>Organic Polymeric Resins Embedded with Pd NPs: Newly Designed, Efficient and Chemoselective Catalyst for Reduction of Nitrobenzenes
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2017 (English)In: Current Organocatalysis, ISSN 2213-3372, Vol. 4, no 1, p. 48-61Article in journal (Refereed) Published
Abstract [en]

Background: Organic polymer supported palladium nanoparticles (NPs) are important for use as heterogeneous catalyst in various organic reactions. This works describes Pd Nps immobilized on to polystyrene-based ion-exchange resin surface for use as catalyst in the reduction of nitrobenzenes. The heterogeneous catalyst was found useful for hydrogenation of nitro group under both catalytic transfer hydrogenation (CTH) as well as by using molecular hydrogen (H2).

Methods: The catalyst was prepared from Amberlite IRA 900 Cl after rinsing with formic acid (10%) and subsequent treatment with Na2PdCl4 in DMF. The resulting Pd Nps immobilized resins was designated as VersaCat Pd and used for CTH of nitrobenzenes in the presence of H-donors (sodium formate, formic acid, hydrazine hydrate) and also for hydrogenation with H2 gas. The catalyst was characterized by FT-IR, MAS-NMR, SEM, TEM and XPS and surface morphologies were studied before and after the reaction.

Results: Hydrogenations of nitrobenzenes under CTH using different H-source and direct use of H2 gas were achieved successfully with good to excellent yields. Reactions were performed under mild conditions and high degree of chemoselectivity was also observed. The catalyst was recyclable, used for six consecutive runs with appreciable conversions and showed higher activity (> 3 times) in terms of metalcontent than commercially available Pd/C (10%) in the hydrogenation of nitrobenzenes using H2 gas. The TEM images showed that Pd Nps are evenly distributed with size 50-200 mm on polymeric matrices and there was no significant changes observed after the first catalytic run. However, considerable rupture of the polymeric surface occurred after six runs, as seen from SEM studies.

Conclusion: The present study establishes high catalytic efficiency and chemoselectivity of the newly developed organic polystyrene-based resin-soaked Pd NPs (VersaCat Pd) in the reduction of nitrobenzenes. Both CTH and hydrogenation using H2 gas were successfully done. Interestingly, hydrazine hydrate offered excellent control over chemoselectivity under CTH conditions and allowed clean conversion from nitro to amine, while keeping a chloro substitutent unaffected. Hydrogenation using molecular H2 gave maximum TOF. Easy preparation, high efficacy, TOF, chemoselectivity, and versatile applications are notable features for this heterogeneous palladium catalyst (VersaCat Pd). These features are often required in chemical industries.

Place, publisher, year, edition, pages
Bentham Science Publishers, 2017
Keywords
Chemoselectivity, heterogeneous catalysis, nitrobenzenes, organic polymer, palladium
National Category
Organic Chemistry
Identifiers
urn:nbn:se:umu:diva-128914 (URN)10.2174/2213337203666160524143615 (DOI)000406982200004 ()
Funder
Swedish Research Council, 2010-4730Swedish Research Council, 2012-4000
Available from: 2016-12-19 Created: 2016-12-19 Last updated: 2018-06-09Bibliographically approved
Lundstedt, S., Bandowe, B. A., Wilcke, W., Boll, E., Christensen, J. H., Vila, J., . . . Ricci, M. (2014). First intercomparison study on the analysis of oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) and nitrogen heterocyclic polycyclic aromatic compounds (N-PACs) in contaminated soil. TrAC. Trends in analytical chemistry, 57, 83-92
Open this publication in new window or tab >>First intercomparison study on the analysis of oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) and nitrogen heterocyclic polycyclic aromatic compounds (N-PACs) in contaminated soil
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2014 (English)In: TrAC. Trends in analytical chemistry, ISSN 0165-9936, E-ISSN 1879-3142, Vol. 57, p. 83-92Article, review/survey (Refereed) Published
Abstract [en]

Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) and nitrogen heterocyclic polycyclic aromatic compounds (N-PACs) are toxic, highly leachable and often abundant at sites that are also contaminated with PAHs. However, due to lack of regulations and standardized methods for their analysis, they are seldom included in monitoring and risk-assessment programs. This intercomparison study constitutes an important step in the harmonization of the analytical methods currently used, and may also be considered a first step towards the certification of reference materials for these compounds. The results showed that the participants were able to determine oxy-PAHs with accuracy similar to PAHs, with average determined mass fractions agreeing well with the known levels in a spiked soil and acceptable inter- and intra-laboratory precisions for all soils analyzed. For the N-PACs, the results were less satisfactory, and have to be improved by using analytical methods more specifically optimized for these compounds.

Keywords
Analytical method, Contaminated soil, Intercomparison study, Nitrogen heterocyclic polycyclic aromatic compound, N-PAC, Oxygenated polycyclic aromatic hydrocarbon, Oxy-PAH, Polar polycyclic aromatic compound, Polycyclic aromatic compound, Polycyclic aromatic hydrocarbon
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-90865 (URN)10.1016/j.trac.2014.01.007 (DOI)000336711700026 ()
Available from: 2014-07-15 Created: 2014-07-01 Last updated: 2018-06-07Bibliographically approved
Elhaj, A. & Irgum, K. (2014). Monolithic space-filling porous materials from engineering plastics by thermally induced phase separation. ACS Applied Materials and Interfaces, 6(18), 15653-15666
Open this publication in new window or tab >>Monolithic space-filling porous materials from engineering plastics by thermally induced phase separation
2014 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, no 18, p. 15653-15666Article in journal (Refereed) Published
Abstract [en]

Six different uncompounded engineering and commodity polymers were evaluated for their ability to produce space-filling monolithic entities by thermally induced phase separation (TIPS) from 22 different solvents. Attempts were first made to dissolve the polymers at elevated temperatures, selected below the boiling point of each solvent. Then the solutions of polymers that were homogeneous dissolved underwent a controlled temperature decrease to induce a phase separation as the upper critical solution temperature was passed. Twelve of the solvents gave monolithic entities by this procedure, materials that were characterized with regard to their specific surface area and pore size distribution. These measured parameters were then correlated with their macroporous morphology, assessed by scanning electron microscopy. Monolithic materials with widely different mesoporous properties were obtained with specific surface areas ranging from 169 m(2)/g to structures with essentially nonporous skeletons and distinct mesopore size distribution modes from 6 to 15 nm. The materials furthermore had a wide variation in their macroporous morphologies-among the same polymer processed in different solvents and between different polymers dissolved in the same solvent. TIPS processing therefore appears to be a viable route to prepare space-filling meso- and macroporous support materials for a wide variety of purposes in separation science and heterogeneous chemistry.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2014
Keywords
monolithic supports, polymeric scaffolds, heterogeneous chemistry, separation science, thermally induced phase separation
National Category
Chemical Sciences Nano Technology
Research subject
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-89306 (URN)10.1021/am502977z (DOI)000342328300006 ()
Funder
Swedish Research Council, 2012-4000
Note

Included in thesis in manuscript form.

Available from: 2014-05-27 Created: 2014-05-27 Last updated: 2018-06-07Bibliographically approved
Dinh, N. P., Jonsson, T. & Irgum, K. (2013). Water uptake on polar stationary phases under conditions for hydrophilic interaction chromatography and its relation to solute retention. Journal of Chromatography A, 1320, 33-47
Open this publication in new window or tab >>Water uptake on polar stationary phases under conditions for hydrophilic interaction chromatography and its relation to solute retention
2013 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1320, p. 33-47Article in journal (Other academic) Published
Abstract [en]

In hydrophilic interaction chromatography, water is known to accumulate on the stationary phase to form a water enriched layer, which is believed to play an important role in the retention mechanism. To gain a better understanding retention mechanism in HILIC, we have determined the water uptake on twelve different HILIC stationary phases. Non-modified and monomerically functionalized silica phases followed a pattern of monolayer formation followed by multiple layer adsorption, while the water uptake on polymerically functionalized silica stationary phase showed the characteristics of formation and swelling of hydrogels. This difference in the nature of water accumulation was found to be related to different water uptake patterns when methanol and tetrahydrofuran were added to 80:20 % (v/v) acetonitrile/water by replacing 5 % of the acetonitrile as tertiary solvents, and also when ammonium acetate was added as buffering electrolyte. The relationship between water uptake and retention mechanism was investigated by looking at the correlation between retention factors of neutral analytes and phase ratios of HILIC columns, calculated either as surface area (adsorption) or volume of the water layer enriched from the acetonitrile/water eluent (partitioning). Regardless of the adsorption or partitioning mechanism, the interaction of neutral analytes and stationary phase could be mainly the hydrogen bonding between analytes and the accumulated water in the water enriched layer.

Place, publisher, year, edition, pages
Elsevier, 2013
Keywords
HILIC, HPLC, Retention mechanism, Stationary phases, Eluents
National Category
Analytical Chemistry Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-68067 (URN)10.1016/j.chroma.2013.09.061 (DOI)000327922100005 ()
Funder
Swedish Research Council, 2008-3621, 2012-4000
Note

Manuscript version included in dissertation with the title: Water uptake on polar stationary phases under HILIC conditions and its relation to solute retention

Available from: 2013-04-11 Created: 2013-04-11 Last updated: 2018-06-08Bibliographically approved
Wikberg, E., Sparrman, T., Viklund, C., Jonsson, T. & Irgum, K. (2011). A 2H nuclear magnetic resonance study of the state of water in neat silica and zwitterionic stationary phases and its influence on the chromatographic retention characteristics in hydrophilic interaction high-performance liquid chromatography. Journal of Chromatography A, 1218(38), 6630-6638
Open this publication in new window or tab >>A 2H nuclear magnetic resonance study of the state of water in neat silica and zwitterionic stationary phases and its influence on the chromatographic retention characteristics in hydrophilic interaction high-performance liquid chromatography
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2011 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 38, p. 6630-6638Article in journal (Refereed) Published
Abstract [en]

(2)H NMR has been used as a tool for probing the state of water in hydrophilic stationary phases for liquid chromatography at temperatures between -80 and +4°C. The fraction of water that remained unfrozen in four different neat silicas with nominal pore sizes between 60 and 300Å, and in silicas with polymeric sulfobetaine zwitterionic functionalities prepared in different ways, could be determined by measurements of the line widths and temperature-corrected integrals of the (2)H signals. The phase transitions detected during thawing made it possible to estimate the amount of non-freezable water in each phase. A distinct difference was seen between the neat and modified silicas tested. For the neat silicas, the relationship between the freezing point depression and their pore size followed the expected Gibbs-Thomson relationship. The polymeric stationary phases were found to contain considerably higher amounts of non-freezable water compared to the neat silica, which is attributed to the structural effect that the sulfobetaine polymers have on the water layer close to the stationary phase surface. The sulfobetaine stationary phases were used alongside the 100Å silica to separate a number of polar compounds in hydrophilic interaction (HILIC) mode, and the retention characteristics could be explained in terms of the surface water structure, as well as by the porous properties of the stationary phases. This provides solid evidence supporting a partitioning mechanism, or at least of the existence of an immobilized layer of water into which partitioning could be occurring.

Place, publisher, year, edition, pages
Elsevier, 2011
Keywords
HPLC, Hydrophilic interaction chromatography, Retention mechanisms
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-46064 (URN)10.1016/j.chroma.2011.04.056 (DOI)21855078 (PubMedID)
Note
Available online 29 April 2011 Available from: 2011-08-25 Created: 2011-08-25 Last updated: 2018-06-08Bibliographically approved
Dinh, N. P., Jonsson, T. & Irgum, K. (2011). Probing the interaction mode in hydrophilic interaction chromatography. Journal of Chromatography A, 1218(35), 5880-5891
Open this publication in new window or tab >>Probing the interaction mode in hydrophilic interaction chromatography
2011 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 35, p. 5880-5891Article in journal (Refereed) Published
Abstract [en]

This work aims at characterizing interactions between a select set of probes and 22 hydrophilic and polar commercial stationary phases, to develop an understanding of the relationship between the chemical properties of those phases and their interplay with the eluent and solutes in hydrophilic interaction chromatography. "Hydrophilic interaction" is a somewhat inexact term, and an attempt was therefore made to characterize the interactions involved in HILIC as hydrophilic, hydrophobic, electrostatic, hydrogen bonding, dipole-dipole, π-π interaction, and shape-selectivity. Each specific interaction was quantified from the separation factors of a pair of similar substances of which one had properties promoting the interaction mode being probed while the other did not. The effects of particle size and pore size of the phases on retention and selectivity were also studied. The phases investigated covered a wide range of surface functional groups including zwitterionic (sulfobetaine and phosphocholine), neutral (amide and hydroxyl), cationic (amine), and anionic (sulfonic acid and silanol). Principal component analysis of the data showed that partitioning was a dominating mechanism for uncharged solutes in HILIC. However, correlations between functional groups and interactions were also observed, which confirms that the HILIC retention mechanism is partly contributed by adsorption mechanisms involving electrostatic interaction and multipoint hydrogen bonding. Phases with smaller pore diameters yielded longer retention of solutes, but did not significantly change the column selectivities. The particle diameter had no significant effect, neither on retention, nor on the selectivities. An increased water content in the eluent reduced the multipoint hydrogen bonding interactions, while an increased electrolyte concentration lowered the selectivities of the tested columns and made their interaction patterns more similar.

Place, publisher, year, edition, pages
Elsevier, 2011
Keywords
hydrophilic-interaction chromatography, retention factors, selectivity, column classification, partial least squares
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-46063 (URN)10.1016/j.chroma.2011.06.037 (DOI)21803363 (PubMedID)
Available from: 2011-08-25 Created: 2011-08-25 Last updated: 2018-06-08Bibliographically approved
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