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Yu, C., Turner, S., Huotari, S., Chen, N., Shchukarev, A., Österholm, P., . . . Åström, M. E. (2024). Manganese cycling and transport in boreal estuaries impacted by acidic Mn-rich drainage. Geochimica et Cosmochimica Acta, 365, 136-157
Open this publication in new window or tab >>Manganese cycling and transport in boreal estuaries impacted by acidic Mn-rich drainage
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2024 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 365, p. 136-157Article in journal (Refereed) Published
Abstract [en]

As critical transition zones between the land and the sea, estuaries are not only hotspots of hydrogeochemical and microbial processes/reactions, but also play a vital role in processing and transferring terrestrial fluxes of metals and nutrients to the sea. This study focused on three estuaries in the Gulf of Bothnia. All of them experience frequent inputs of acidic and Mn/metal-rich creek waters due to flushing of acid sulfate soils that are widespread in the creekś catchments. Analyzing existing long-termwaterchemistrydata revealed a strong seasonal variation of Mn loads, with the highest values in spring (after snow melt) and autumn (after heavy rains). We sampled surface waters, suspended particulate matter (SPM), and sediments from the estuarine mixing zones and determined the loads and solid-phase speciation of Mn as well as the composition and metabolic potentials of microbial communities. The results showed that the removal, cycling, and lateral transport of Mn were governed by similar phases and processes in the three estuaries. Manganese X-ray absorption spectroscopy data of the SPM suggested that the removal of Mn was regulated by silicates (e.g., biotite), organically complexed Mn(II), and MnOx (dominated by groutite and phyllomanganates). While the fractional amounts of silicate-bound Mn(II) were overall low and constant throughout the estuaries, MnOx was strongly correlated with the Mn loadings of the SPM and thus the main vector for the removal of Mn in the central and outer parts of the estuaries, along with organically complexed Mn(II). Down estuary, both the fractional amounts and average Mn oxidation state of the MnOx phases increased with (i) the total Mn loads on the SPM samples and (ii) the relative abundances of several potential Mn-oxidizing bacteria (Flavobacterium, Caulobacter, Mycobacterium, and Pedobacter) in the surface waters. These features collectively suggested that the oxidation of Mn, probably mediated by the potential Mn-oxidizing microorganisms, became more extensive and complete towards the central and outer parts of the estuaries. At two sites in the central parts of one estuary, abundant phyllomanganates occurred in the surface sediments, but were converted to surface-sorbed Mn(II) phases at deeper layers (>3–4 cm). The occurrence of phyllomanganates may have suppressed the reduction of sulfate in the surface sediments, pushing down the methane sulfate transition zone that is typically shallow in estuarine sediments. At the outermost site in the estuary, deposited MnOx were reduced immediately at the water–sediment interface and converted most likely to Mn carbonate. The mobile Mn species produced by the Mn reduction processes (e.g., aqueous Mn(II) and ligand complexed Mn(III)) could partly diffuse into the overlying waters and, together with the estuarine Mn loads carried by the surface waters, transfer large amounts of reactive Mn into open coastal areas and subsequently contribute to Mn shuttling and inter-linked biogeochemical processes over the seafloor. Given the widespread occurrence of acid sulfate soils and other sulfidic geological materials on many coastal plains worldwide, the identified Mn attenuation and transport mechanisms are relevant for many estuaries globally.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Manganese attenuation and recycling, Acid sulfate soil, Estuary, Baltic Sea, X-ray absorption spectroscopy, Anaerobic oxidation of methane
National Category
Geochemistry
Identifiers
urn:nbn:se:umu:diva-218103 (URN)10.1016/j.gca.2023.12.004 (DOI)2-s2.0-85180486003 (Scopus ID)
Funder
The Geological Survey of Sweden (SGU), 36-2051/2016Swedish Research Council, 2020-04853Swedish Research Council, 2018-07152Vinnova, 2018-04969Swedish Research Council Formas, 2019-02496
Available from: 2023-12-15 Created: 2023-12-15 Last updated: 2024-01-05Bibliographically approved
Cant, D. J. H., Pei, Y., Shchukarev, A., Ramstedt, M., Marques, S. S., Segundo, M. A., . . . Minelli, C. (2023). Cryo-XPS for surface characterization of nanomedicines. Journal of Physical Chemistry A, 127(39), 8220-8227
Open this publication in new window or tab >>Cryo-XPS for surface characterization of nanomedicines
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2023 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 127, no 39, p. 8220-8227Article in journal (Refereed) Published
Abstract [en]

Nanoparticles used for medical applications commonly possess coatings or surface functionalities intended to provide specific behavior in vivo, for example, the use of PEG to provide stealth properties. Direct, quantitative measurement of the surface chemistry and composition of such systems in a hydrated environment has thus far not been demonstrated, yet such measurements are of great importance for the development of nanomedicine systems. Here we demonstrate the first use of cryo-XPS for the measurement of two PEG-functionalized nanomedicines: a polymeric drug delivery system and a lipid nanoparticle mRNA carrier. The observed differences between cryo-XPS and standard XPS measurements indicate the potential of cryo-XPS for providing quantitative measurements of such nanoparticle systems in hydrated conditions.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Analytical Chemistry Materials Chemistry
Identifiers
urn:nbn:se:umu:diva-215315 (URN)10.1021/acs.jpca.3c03879 (DOI)001070270700001 ()37733882 (PubMedID)2-s2.0-85173556161 (Scopus ID)
Funder
EU, Horizon 2020, 825828
Available from: 2023-10-17 Created: 2023-10-17 Last updated: 2023-11-06Bibliographically approved
Ramstedt, M. & Shchukarev, A. (2023). XPS spectra from nucleobases, DNA, and RNA. Surface Science Spectra, 30(1), Article ID 014011.
Open this publication in new window or tab >>XPS spectra from nucleobases, DNA, and RNA
2023 (English)In: Surface Science Spectra, ISSN 1055-5269, E-ISSN 1520-8575, Vol. 30, no 1, article id 014011Article in journal (Refereed) Published
Abstract [en]

X-ray photoelectron spectroscopy was used to analyze commercially available powders of thymine, uracil, cytosine, guanine, adenine, as well as DNA isolated from salmon testes and RNA from torula yeast. The powders were pressed onto a sample holder and analyzed as received from the manufacturer. Survey spectra and high-resolution spectra of O 1s, N 1s, C 1s of all nucleobases are reported, including a small Na 1s contamination in cytosine. Spectra of DNA and RNA are also included for comparison. Furthermore, the presented data are compared with previously published results, as well as theoretical values, and differences are discussed.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2023
National Category
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-208283 (URN)10.1116/6.0002368 (DOI)000988472100001 ()2-s2.0-85159787197 (Scopus ID)
Available from: 2023-05-16 Created: 2023-05-16 Last updated: 2023-06-21Bibliographically approved
Vucetic, N., Virtanen, P., Shchukarev, A., Salmi, T. & Mikkola, J.-P. (2022). Competing commercial catalysts: Unprecedented catalyst activity and stability of Mizoroki-Heck reaction in a continuous packed bed reactor. Chemical Engineering Journal, 433, Article ID 134432.
Open this publication in new window or tab >>Competing commercial catalysts: Unprecedented catalyst activity and stability of Mizoroki-Heck reaction in a continuous packed bed reactor
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2022 (English)In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 433, article id 134432Article in journal (Refereed) Published
Abstract [en]

Main obstacle for adopting continuous processes as a standard technology for Mizoroki-Heck reaction usually lies in its specific reaction mechanism. Here we present an important step forward answering the challenges unraveled through a comprehensive study that provides deeper understanding on the Mizoroki-Heck reaction, in particular the case when iodobenzene and butyl acrylate react in a continuous packed bed reactor in the presence of a Pd Supported Ionic Liquid Catalyst (SILCA). On-line UV–VIS spectrometry supported by ICP-OES, TEM and XPS measurements were carried out and the catalyst leaching was minimized. Finally, simple continuous flow process was proposed resulting in a high catalytic activity (up to 1470 molArI molPd−1h−1) and reaching productivity in the range of 12,000 to 16,000 molArI molPd−1 thus competing with the performance of commercial catalysts.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Continuous flow, Heterogeneous catalysis, Mizoroki-Heck reaction, Release-and-catch mechanism, Supported ionic liquid catalyst
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:umu:diva-191456 (URN)10.1016/j.cej.2021.134432 (DOI)000773543000002 ()2-s2.0-85122491311 (Scopus ID)
Funder
Bio4EnergySwedish Research Council
Note

Volume 433, Part 1.

Available from: 2022-01-18 Created: 2022-01-18 Last updated: 2023-09-05Bibliographically approved
Ramstedt, M. & Shchukarev, A. (2022). Cryo-XPS spectra from bacterial reference strain Pseudomonas fluorescens DSM50090. Surface Science Spectra, 29(1), Article ID 014010.
Open this publication in new window or tab >>Cryo-XPS spectra from bacterial reference strain Pseudomonas fluorescens DSM50090
2022 (English)In: Surface Science Spectra, ISSN 1055-5269, E-ISSN 1520-8575, Vol. 29, no 1, article id 014010Article in journal (Refereed) Published
Abstract [en]

Cryogenic x-ray photoelectron spectroscopy was used to analyze the cell envelope of intact and hydrated Gram-negative bacteria of the species Pseudomonas fluorescens. We used a reference strain, DSM50090, from the German microbial culture collection, which we previously have suggested would function well as a reference strain for future XPS analyses of Gram-negative bacteria. Bacteria were grown on nutrient agar plates at room temperature, collected with a cultivation loop, and washed using phosphate buffered saline. An aliquot of the cell pellet was fast-frozen on the sample holder in the sample introduction chamber to a temperature of 103 K and kept frozen throughout the measurement. Survey spectra and high-resolution spectra of Na 1s, O 1s, N 1s, C 1s, Cl 2p, S 2p, and P 2p are reported. The spectra obtained from the analyzed cells represent a combined signal from O, N, C, and S atoms in proteins, lipids, and polysaccharides at the cell surface. Furthermore, signal from P, Na, K, and Cl atoms was present both originating from processes in the cell envelope and remnants from the wash buffer.

Place, publisher, year, edition, pages
AVS Science and Technology Society, 2022
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-193343 (URN)10.1116/6.0001575 (DOI)000780202400001 ()2-s2.0-85127307826 (Scopus ID)
Available from: 2022-03-28 Created: 2022-03-28 Last updated: 2023-03-24Bibliographically approved
Luong, N. T., Ilton, E. S., Shchukarev, A. & Boily, J.-F. (2022). Water film-driven Mn (oxy)(hydr)oxide nanocoating growth on rhodochrosite. Geochimica et Cosmochimica Acta, 329, 87-105
Open this publication in new window or tab >>Water film-driven Mn (oxy)(hydr)oxide nanocoating growth on rhodochrosite
2022 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 329, p. 87-105Article in journal (Refereed) Published
Abstract [en]

Minerals exposed to moist air stabilize thin water films that drive a score of chemical reactions of great importance to water-unsaturated terrestrial environments. In this study, we identified Mn (oxy)(hydr)oxide nanocoatings formed by the dissolution, oxidation and precipitation of Mn in oxygenated water films grown on rhodochrosite (MnCO3) microparticles. Nanocoatings that could be identified by vibrational spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and (scanning and transmission) electron microscopy formed in water films containing the equivalent of at least 7 monolayers (∼84 H2O/nm2). These films were formed by exposing microparticles to moist air with at least 50% relative humidity (RH). Films of neutral pH reacted up to 14% of the MnII located in the topmost ∼5 nm region of the microparticles in atmospheres of up to 90% RH for 7 d. These reactions produced MnOOH, birnessite (MnO2) and hausmannite (Mn3O4) nanoparticles of low crystallinity, while exposure to atmospheric air for 1 yr. converted only 2% of MnII in this region to MnOOH. In contrast, reactions in alkaline water films converted up to ∼75% of the MnII but only after 16 d of reaction. These films produced MnOOH and MnO2 of low crystallinity, as well as crystalline hausmannite. Kinetic modeling of the time-resolved growth of the Mn[sbnd]O stretching vibrational bands of these nanocoatings revealed two concurrent reaction processes. A 1rst-order process was assigned to nucleation events terminating only after a few hours, and a 0-order process was assigned to the sustained growth of nanocoatings from these nuclei over longer reaction time. By identifying nanocoatings formed by water film-driven reactions on rhodochrosite, our study adds new insight into mineralogical transformations relevant to anoxic–oxic boundaries in water-unsaturated environments.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Oxidation, Precipitation, Rhodochrosite, Water films
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-203210 (URN)10.1016/j.gca.2022.05.019 (DOI)000818523300006 ()2-s2.0-85132406337 (Scopus ID)
Funder
Swedish Research Council, 2020-04853Swedish Research Council, 2016-03808Umeå University
Available from: 2023-01-18 Created: 2023-01-18 Last updated: 2023-09-04Bibliographically approved
Shchukarev, A., Backman, E., Watts, S., Salentinig, S., Urban, C. F. & Ramstedt, M. (2021). Applying Cryo-X-ray Photoelectron Spectroscopy to Study the Surface Chemical Composition of Fungi and Viruses. Frontiers in Chemistry, 9, Article ID 666853.
Open this publication in new window or tab >>Applying Cryo-X-ray Photoelectron Spectroscopy to Study the Surface Chemical Composition of Fungi and Viruses
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2021 (English)In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 9, article id 666853Article in journal (Refereed) Published
Abstract [en]

Interaction between microorganisms and their surroundings are generally mediated via the cell wall or cell envelope. An understanding of the overall chemical composition of these surface layers may give clues on how these interactions occur and suggest mechanisms to manipulate them. This knowledge is key, for instance, in research aiming to reduce colonization of medical devices and device-related infections from different types of microorganisms. In this context, X-ray photoelectron spectroscopy (XPS) is a powerful technique as its analysis depth below 10 nm enables studies of the outermost surface structures of microorganism. Of specific interest for the study of biological systems is cryogenic XPS (cryo-XPS). This technique allows studies of intact fast-frozen hydrated samples without the need for pre-treatment procedures that may cause the cell structure to collapse or change due to the loss of water. Previously, cryo-XPS has been applied to study bacterial and algal surfaces with respect to their composition of lipids, polysaccharides and peptide (protein and/or peptidoglycan). This contribution focuses onto two other groups of microorganisms with widely different architecture and modes of life, namely fungi and viruses. It evaluates to what extent existing models for data treatment of XPS spectra can be applied to understand the chemical composition of their very different surface layers. XPS data from model organisms as well as reference substances representing specific building blocks of their surface were collected and are presented. These results aims to guide future analysis of the surface chemical composition of biological systems.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2021
Keywords
cryo-XPS, virus, fungi, reference data, bacteriophage, surface chemistry, cell wall
National Category
Other Chemistry Topics Biophysics Physical Chemistry Microbiology Other Medical Biotechnology
Identifiers
urn:nbn:se:umu:diva-183667 (URN)10.3389/fchem.2021.666853 (DOI)000660083200001 ()34124001 (PubMedID)2-s2.0-85107576942 (Scopus ID)
Funder
The Kempe Foundations, JCK-1720
Available from: 2021-05-28 Created: 2021-05-28 Last updated: 2023-03-24Bibliographically approved
Yun, J., Kumar, A., Removski, N., Shchukarev, A., Link, N., Boily, J.-F. & Bertram, A. K. (2021). Effects of Inorganic Acids and Organic Solutes on the Ice Nucleating Ability and Surface Properties of Potassium-Rich Feldspar. ACS Earth and Space Chemistry, 5(5), 1212-1222
Open this publication in new window or tab >>Effects of Inorganic Acids and Organic Solutes on the Ice Nucleating Ability and Surface Properties of Potassium-Rich Feldspar
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2021 (English)In: ACS Earth and Space Chemistry, E-ISSN 2472-3452, Vol. 5, no 5, p. 1212-1222Article in journal (Refereed) Published
Abstract [en]

Mineral dust particles can initiate the freezing of cloud droplets in the atmosphere. The freezing efficiency of these particles can, however, be strongly affected by solutes, such as inorganic acids, polyols, and carboxylic acids. Here, we report the effects of inorganic acids (HNO3 and HCl), polyols, and carboxylic acids at low concentrations on the ice nucleating ability of potassium-rich feldspar (K-rich feldspar) using the droplet freezing technique. The inorganic acids and carboxylic acids decreased the median freezing temperature of droplets containing K-rich feldspar by up to 7 °C, while the polyols had no significant effect on the median freezing temperature. For the inorganic acids and carboxylic acids, the median freezing temperature was a strong function of the pH of the droplets, with the median freezing temperature decreasing as the pH decreased. By examining the surface properties of K-rich feldspar exposed to different concentrations of HCl with cryogenic X-ray photoelectron spectroscopy, we show that the decrease in the ice nucleating ability of K-rich feldspar by the inorganic acids and carboxylic acids was likely caused by ion exchange (H3O+ with parent K+ in microcline) and the incongruent dissolution of Al with respect to Si at K-rich feldspar surfaces. The decrease in the ice nucleating ability of K-rich feldspar by the carboxylic acids only related to the pH of the droplets rather than the type of carboxylic acid and their expected binding mechanisms on K-rich feldspar. This study focuses on rare ice nucleating active sites (with an ice nucleating active site density of 10-600 cm-2) of the K-rich feldspar and short exposure times between the solutes and the K-rich feldspar. Further studies are needed to investigate more abundant ice nucleating active sites and longer exposure times, as well as K-rich feldspar samples from different sources.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2021
Keywords
feldspar, ice nucleating particles, immersion freezing, inorganic acids, organic solutes, pH
National Category
Physical Chemistry Inorganic Chemistry Meteorology and Atmospheric Sciences
Identifiers
urn:nbn:se:umu:diva-183560 (URN)10.1021/acsearthspacechem.1c00034 (DOI)000655638500021 ()2-s2.0-85105722667 (Scopus ID)
Available from: 2021-06-15 Created: 2021-06-15 Last updated: 2023-09-05Bibliographically approved
Barišić, A., Lützenkirchen, J., Bebić, N., Li, Q., Hanna, K., Shchukarev, A. & Begović, T. (2021). Experimental Data Contributing to the Elusive Surface Charge of Inert Materials in Contact with Aqueous Media. Colloids and interfaces, 5(1), Article ID 6.
Open this publication in new window or tab >>Experimental Data Contributing to the Elusive Surface Charge of Inert Materials in Contact with Aqueous Media
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2021 (English)In: Colloids and interfaces, E-ISSN 2504-5377, Vol. 5, no 1, article id 6Article in journal (Other academic) Published
Abstract [en]

We studied the charging of inert surfaces (polytetrafluoroethylene, i.e., PTFE; graphite; graphene; and hydrophobic silica) using classical colloid chemistry approaches. Potentiometric titrations showed that these surfaces acquired less charge from proton-related reactions than oxide minerals. The data from batch-type titrations for PTFE powder did not show an effect of ionic strength, which was also in contrast with results for classical colloids. In agreement with classical colloids, the electrokinetic results for inert surfaces showed the typical salt level dependence. In some cases, the point of zero net proton charge as determined from mass and tentatively from acid–base titration differed from isoelectric points, which has also been previously observed, for example by Chibowski and co-workers for ice electrolyte interfaces. Finally, we found no evidence for surface contaminations of our PTFE particles before and after immersion in aqueous solutions. Only in the presence of NaCl-containing solutions did cryo-XPS detect oxygen from water. We believe that our low isoelectric points for PTFE were not due to impurities. Moreover, the measured buffering at pH 3 could not be explained by sub-micromolar concentrations of contaminants. The most comprehensive explanation for the various sets of data is that hydroxide ion accumulation occurred at the interfaces between inert surfaces and aqueous solutions.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
surface charge, zeta-potential, PTFE, graphite, graphene
National Category
Physical Chemistry Materials Chemistry Other Chemistry Topics Inorganic Chemistry Theoretical Chemistry
Identifiers
urn:nbn:se:umu:diva-179388 (URN)10.3390/colloids5010006 (DOI)000633103200001 ()2-s2.0-85104877929 (Scopus ID)
Available from: 2021-02-01 Created: 2021-02-01 Last updated: 2023-09-05Bibliographically approved
Martínez-Klimov, M. E., Mäki-Arvela, P., Vajglova, Z., Alda-Onggar, M., Angervo, I., Kumar, N., . . . Murzin, D. Y. (2021). Hydrodeoxygenation of Isoeugenol over Carbon-Supported Pt and Pt-Re Catalysts for Production of Renewable Jet Fuel. Energy & Fuels, 35(21), 17755-17768
Open this publication in new window or tab >>Hydrodeoxygenation of Isoeugenol over Carbon-Supported Pt and Pt-Re Catalysts for Production of Renewable Jet Fuel
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2021 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 35, no 21, p. 17755-17768Article in journal (Refereed) Published
Abstract [en]

A series of monometallic platinum and bimetallic platinum–rhenium catalysts supported on mesoporous carbon Sibunit, which is a type of mesoporous, microcrystalline carbon, were investigated for hydrodeoxygenation (HDO) of isoeugenol (IE) at 200–300 °C and 30 bar of H2, using dodecane as a solvent. Catalytic activity was tested in a batch reactor to screen the catalysts and, for comparison, also in the continuous mode. For batch experiments, complete conversion, and a high yield of the desired product, propylcyclohexane (PCH), were obtained for all bimetallic PtRe/Sibunit in 240 min, with the highest yield of PCH when Pt:Re ratio was 1:1 or 1:3. The results for Pt–Re (1:1) were reproducible, in terms of catalytic activity and reusability of catalysts, which showed no deactivation. Monometallic Pt catalysts displayed low activity. Continuous experiments were performed with PtRe(1:1)/Sibunit at 30 bar H2, 0.5 mL/min of the liquid flow, and temperatures between 75 °C and 200 °C. The distribution of products showed deoxygenation at higher temperatures, while at lower temperatures, mainly oxygenated products were formed. XPS results confirmed the presence of ReOx species, where an increase in the platinum loading resulted in a decrease in the fraction of ReOx species and subsequently lower PCH yield.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2021
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:umu:diva-189627 (URN)10.1021/acs.energyfuels.1c02656 (DOI)000716453500053 ()2-s2.0-85118760514 (Scopus ID)
Available from: 2021-11-17 Created: 2021-11-17 Last updated: 2021-12-30Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-4766-2672

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