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Soder-Walz JM, Deobald D, Vicent T, Marco-Urrea E, Adrian L. MecE, MecB, and MecC proteins orchestrate methyl group transfer during dichloromethane fermentation. Appl Environ Microbiol 2024:e0097824. [PMID: 39320083 DOI: 10.1128/aem.00978-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Accepted: 09/06/2024] [Indexed: 09/26/2024] Open
Abstract
Dichloromethane (DCM), a common hazardous industrial chemical, is anaerobically metabolized by four bacterial genera: Dehalobacter, Dehalobacterium, Ca. Dichloromethanomonas, and Ca. Formimonas. However, the pivotal methyltransferases responsible for DCM transformation have remained elusive. In this study, we investigated the DCM catabolism of Dehalobacterium formicoaceticum strain EZ94, contained in an enriched culture, using a combination of biochemical approaches. Initially, enzymatic assays were conducted with cell-free protein extracts, after protein separation by blue native polyacrylamide gel electrophoresis. In the slices with the highest DCM transformation activity, a high absolute abundance of the methyltransferase MecC was revealed by mass spectrometry. Enzymatic activity assays with heterologously expressed MecB, MecC, and MecE from strain EZ94 showed complete DCM transformation only when all three enzymes were present. Our experimental results, coupled with the computational analysis of MecB, MecC, and MecE sequences, enabled us to assign specific roles in DCM transformation to each of the proteins. Our findings reveal that both MecE and MecC are zinc-dependent methyltransferases responsible for DCM demethylation and re-methylation of a product, respectively. MecB functions as a cobalamin-dependent shuttle protein transferring the methyl group between MecE and MecC. This study provides the first biochemical evidence of the enzymes involved in the anaerobic metabolism of DCM.IMPORTANCEDichloromethane (DCM) is a priority regulated pollutant frequently detected in groundwater. In this work, we identify the proteins responsible for the transformation of DCM fermentation in Dehalobacterium formicoaceticum strain EZ94 using a combination of biochemical approaches, heterologous expression of proteins, and computational analysis. These findings provide the basis to apply these proteins as biological markers to monitor bioremediation processes in the field.
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Affiliation(s)
- Jesica M Soder-Walz
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
| | - Darja Deobald
- Department Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Teresa Vicent
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
| | - Ernest Marco-Urrea
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
| | - Lorenz Adrian
- Department Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
- Geobiotechnology, Technische Universität Berlin, Berlin, Germany
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Gonzalez-Pizarro P, Brazzi L, Koch S, Trinks A, Muret J, Sperna Weiland N, Jovanovic G, Cortegiani A, Fernandes TD, Kranke P, Malisiova A, McConnell P, Misquita L, Romero CS, Bilotta F, De Robertis E, Buhre W. European Society of Anaesthesiology and Intensive Care consensus document on sustainability: 4 scopes to achieve a more sustainable practice. Eur J Anaesthesiol 2024; 41:260-277. [PMID: 38235604 DOI: 10.1097/eja.0000000000001942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Climate change is a defining issue for our generation. The carbon footprint of clinical practice accounts for 4.7% of European greenhouse gas emissions, with the European Union ranking as the third largest contributor to the global healthcare industry's carbon footprint, after the United States and China. Recognising the importance of urgent action, the European Society of Anaesthesiology and Intensive Care (ESAIC) adopted the Glasgow Declaration on Environmental Sustainability in June 2023. Building on this initiative, the ESAIC Sustainability Committee now presents a consensus document in perioperative sustainability. Acknowledging wider dimensions of sustainability, beyond the environmental one, the document recognizes healthcare professionals as cornerstones for sustainable care, and puts forward recommendations in four main areas: direct emissions, energy, supply chain and waste management, and psychological and self-care of healthcare professionals. Given the urgent need to cut global carbon emissions, and the scarcity of evidence-based literature on perioperative sustainability, our methodology is based on expert opinion recommendations. A total of 90 recommendations were drafted by 13 sustainability experts in anaesthesia in March 2023, then validated by 36 experts from 24 different countries in a two-step Delphi validation process in May and June 2023. To accommodate different possibilities for action in high- versus middle-income countries, an 80% agreement threshold was set to ease implementation of the recommendations Europe-wide. All recommendations surpassed the 80% agreement threshold in the first Delphi round, and 88 recommendations achieved an agreement >90% in the second round. Recommendations include the use of very low fresh gas flow, choice of anaesthetic drug, energy and water preserving measures, "5R" policies including choice of plastics and their disposal, and recommendations to keep a healthy work environment or on the importance of fatigue in clinical practice. Executive summaries of recommendations in areas 1, 2 and 3 are available as cognitive aids that can be made available for quick reference in the operating room.
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Affiliation(s)
- Patricio Gonzalez-Pizarro
- From the Department of Paediatric Anaesthesia and Critical Care. La Paz University Hospital, Madrid, Spain (PGP), the Department of Anaesthesia, Intensive Care and Emergency, 'Citta' della Salute e della Scienza' University Hospital, Department of Surgical Science, University of Turin, Turin, Italy (LB), the University of Southern Denmark (SDU) Odense, Department of Anesthesia, Hospital of Nykobing Falster, Denmark (SK), the Department of Anesthesiology and Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, and Humboldt Universität zu Berlin, Campus Charité Mitte, and Campus Virchow Klinikum (SK), the Department of Anaesthesiology. LMU University Hospital, LMU Munich, Germany (AT), the Department of Anaesthesia and Intensive Care. Institute Curie & PSL Research University, Paris, France (JM), the Department of Anaesthesiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands (NSW), the Department of Anaesthesia and Perioperatve Medicine. Medical Faculty, University of Novi Sad, Novi Sad, Serbia (GJ), the Department of Surgical, Oncological and Oral Science, University of Palermo, Italy. Department of Anesthesia, Intensive Care and Emergency, University Hospital Policlinico Paolo Giaccone, Palermo, Italy (AC), the Department of Anaesthesiology, Hospital Pedro Hispano, Matosinhos, Portugal (TDF), the Department of Anaesthesiology, Intensive Care, Emergency and Pain Medicine, University Hospital Würzburg, Germany (PK), the Department of Anaesthesiology and Pain. P&A Kyriakou Children's Hospital Athens Greece (AM), Royal Alexandra Hospital. Paisley, Scotland, United Kingdom (PM), Department of Neuro-anaesthesia and Neurocritical Care, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, London, England, United Kingdom (LM), the Department of Anesthesia, Critical care and Pain Unit, Hospital General Universitario de Valencia. Research Methods Department, European University of Valencia, Spain (CR), the "Sapienza" University of Rome, Department of Anesthesiology and Critical Care, Rome, Italy (FB), the Division of Anaesthesia, Analgesia, and Intensive Care - Department of Medicine and Surgery - University of Perugia Ospedale S. Maria della Misericordia, Perugia, Italy (EDR), the Division of Anaesthesiology, Intensive Care and Emergency Medicine, Department of Anaesthesiology, University Medical Center Utrecht, Utrecht, The Netherlands (WB)
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Cheng S, Yan Z, Shan L, Huang J, Yu Z, Wei Z, Wang H, Li Z, Yang B, Shu J. Novel MCP-Windowed EUV Light Source and Its Mass Spectrometric Application for Detecting Chlorinated Methanes. Anal Chem 2023; 95:16531-16538. [PMID: 37747740 DOI: 10.1021/acs.analchem.3c02365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Various vacuum ultraviolet (VUV) lamps are simple and convenient VUV light sources for mass spectrometry and other research fields. However, the strong absorption of high-energy photons by window materials limits the application of an extreme ultraviolet (EUV) light. In this study, a novel high-flux EUV light source is developed using a microchannel plate (MCP) window to transmit 73.6 nm (16.9 eV) EUV light generated via the radio frequency (RF) inductive discharge of neon. The MCP used is a 0.5 mm thick glass plate with a regular array of microtubes (12 μm i.d.). The photon fluxes of the EUV light source with the MCP window (12 mm i.d.) and an aperture (1.8 mm i.d.) are ∼1.31 × 1014 and ∼9.80 × 1012 photons s-1, respectively, while their corresponding leakage flow rates of the discharge gas are 0.062 and 0.046 cm3 atom s-1, according to the contrast experiments. The transmission efficiency of the MCP to the EUV light is 30.2%, with a 1.2% deviation. An EUV photoionization time-of-flight mass spectrometer (EUV-PI-TOFMS) is built to validate the practicality of the MCP-windowed EUV light source further. The detection sensitivities in 30 s measurements for methyl chloride (CH3Cl), methylene chloride (CH2Cl2), trichloromethane (CHCl3), and carbon tetrachloride (CCl4) in synthetic air are 4366, 4120, 5854, and 4095 counts ppbv-1, respectively. The corresponding 3σ limits of detection (LODs) are 42, 34, 24, and 15 pptv. This study develops a new feasible method for efficiently utilizing high-energy EUV light, with many application prospects in scientific research.
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Affiliation(s)
- Shiyu Cheng
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
| | - Zitao Yan
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
| | - Lixin Shan
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
| | - Jingyun Huang
- China Nuclear Power Engineering Co., Ltd., Beijing 100840, People's Republic of China
| | - Zhangqi Yu
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
| | - Zhiyang Wei
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
| | - Haijie Wang
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
| | - Zhen Li
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
| | - Bo Yang
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
| | - Jinian Shu
- Research Center for Environmental Material and Pollution Control Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, Beijing 101408, People's Republic of China
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4
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Vijayakumar S, Wilmouth DM. Kinetics of the Reactions of Chlorinated Very Short-Lived Substances (VSLSs) with Chlorine Atoms. J Phys Chem A 2023; 127:7284-7294. [PMID: 37595126 DOI: 10.1021/acs.jpca.3c02200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
Chlorinated very short-lived substances (VSLSs), which are not controlled by the Montreal Protocol, are of current concern with regard to recovery of stratospheric ozone. Further study is needed on the temperature dependences of chlorinated VSLSs relevant to atmospheric conditions. Here, the kinetics of chlorinated VSLSs, such as chloroform (CHCl3), dichloromethane (CH2Cl2), dichloroethane (CH2ClCH2Cl), and trichloroethene (C2HCl3) reacting with chlorine atoms, were investigated between 180 and 400 K, expanding the range of temperatures relative to previous studies. RRKM/Master Equation and Canonical Variational Transition State Theory were utilized to calculate the rate coefficients using the MultiWell suite of programs. CCSD(T), QCISD(T), and M062X with aug-cc-pV(T+d)Z levels of theory were used to calculate the kinetic parameters. Arrhenius equations obtained from fits to the calculated rate coefficients are k1 = (2.66 ± 0.7) × 10-12 exp [(-927 ± 131)/T] cm3 molecule-1 s-1, k2 = (8.99 ± 0.3) × 10-12 exp [(-957 ± 19)/T] cm3 molecule-1 s-1, k3 = (1.51 ± 0.16) × 10-11 exp [(-714 ± 54)/T] cm3 molecule-1 s-1, and k4 = (9.17 ± 1.8) × 10-12 exp [(612 ± 101)/T] cm3 molecule-1 s-1 for the reactions of CHCl3, CH2Cl2, CH2ClCH2Cl, and C2HCl3 with Cl atoms, respectively. The rate coefficients for the reactions of chlorinated VSLSs with Cl atoms from this study are compared with the most recent recommended values from the NASA/JPL and IUPAC evaluations and with literature values. The reactivity trends of the reactions are discussed.
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Affiliation(s)
- S Vijayakumar
- Harvard John A. Paulson School of Engineering and Applied Sciences and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 United States
| | - David M Wilmouth
- Harvard John A. Paulson School of Engineering and Applied Sciences and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 United States
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Holland SI, Vázquez-Campos X, Ertan H, Edwards RJ, Manefield MJ, Lee M. Metaproteomics reveals methyltransferases implicated in dichloromethane and glycine betaine fermentation by ' Candidatus Formimonas warabiya' strain DCMF. Front Microbiol 2022; 13:1035247. [PMID: 36569084 PMCID: PMC9768040 DOI: 10.3389/fmicb.2022.1035247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/15/2022] [Indexed: 12/12/2022] Open
Abstract
Dichloromethane (DCM; CH2Cl2) is a widespread pollutant with anthropogenic and natural sources. Anaerobic DCM-dechlorinating bacteria use the Wood-Ljungdahl pathway, yet dechlorination reaction mechanisms remain unclear and the enzyme(s) responsible for carbon-chlorine bond cleavage have not been definitively identified. Of the three bacterial taxa known to carry out anaerobic dechlorination of DCM, 'Candidatus Formimonas warabiya' strain DCMF is the only organism that can also ferment non-chlorinated substrates, including quaternary amines (i.e., choline and glycine betaine) and methanol. Strain DCMF is present within enrichment culture DFE, which was derived from an organochlorine-contaminated aquifer. We utilized the metabolic versatility of strain DCMF to carry out comparative metaproteomics of cultures grown with DCM or glycine betaine. This revealed differential abundance of numerous proteins, including a methyltransferase gene cluster (the mec cassette) that was significantly more abundant during DCM degradation, as well as highly conserved amongst anaerobic DCM-degrading bacteria. This lends strong support to its involvement in DCM dechlorination. A putative glycine betaine methyltransferase was also discovered, adding to the limited knowledge about the fate of this widespread osmolyte in anoxic subsurface environments. Furthermore, the metagenome of enrichment culture DFE was assembled, resulting in five high quality and two low quality draft metagenome-assembled genomes. Metaproteogenomic analysis did not reveal any genes or proteins for utilization of DCM or glycine betaine in the cohabiting bacteria, supporting the previously held idea that they persist via necromass utilization.
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Affiliation(s)
- Sophie I. Holland
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Xabier Vázquez-Campos
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Haluk Ertan
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, Australia
- Department of Molecular Biology and Genetics, Istanbul University, Istanbul, Turkey
| | - Richard J. Edwards
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Michael J. Manefield
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Matthew Lee
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
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Holland SI, Ertan H, Montgomery K, Manefield MJ, Lee M. Novel dichloromethane-fermenting bacteria in the Peptococcaceae family. THE ISME JOURNAL 2021; 15:1709-1721. [PMID: 33452483 PMCID: PMC8163858 DOI: 10.1038/s41396-020-00881-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/29/2020] [Accepted: 12/09/2020] [Indexed: 01/29/2023]
Abstract
Dichloromethane (DCM; CH2Cl2) is a toxic groundwater pollutant that also has a detrimental effect on atmospheric ozone levels. As a dense non-aqueous phase liquid, DCM migrates vertically through groundwater to low redox zones, yet information on anaerobic microbial DCM transformation remains scarce due to a lack of cultured organisms. We report here the characterisation of DCMF, the dominant organism in an anaerobic enrichment culture (DFE) capable of fermenting DCM to the environmentally benign product acetate. Stable carbon isotope experiments demonstrated that the organism assimilated carbon from DCM and bicarbonate via the Wood-Ljungdahl pathway. DCMF is the first anaerobic DCM-degrading population also shown to metabolise non-chlorinated substrates. It appears to be a methylotroph utilising the Wood-Ljungdahl pathway for metabolism of methyl groups from methanol, choline, and glycine betaine. The flux of these substrates from subsurface environments may either directly (DCM, methanol) or indirectly (choline, glycine betaine) affect the climate. Community profiling and cultivation of cohabiting taxa in culture DFE without DCMF suggest that DCMF is the sole organism in this culture responsible for substrate metabolism, while the cohabitants persist via necromass recycling. Genomic and physiological evidence support placement of DCMF in a novel genus within the Peptococcaceae family, 'Candidatus Formimonas warabiya'.
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Affiliation(s)
- Sophie I Holland
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Haluk Ertan
- Department of Molecular Biology and Genetics, Istanbul University, Istanbul, Turkey
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Kate Montgomery
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Michael J Manefield
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Matthew Lee
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia.
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Bensalah N, Midassi S, Ahmad MI, Bedoui A. Degradation of hydroxychloroquine by electrochemical advanced oxidation processes. CHEMICAL ENGINEERING JOURNAL (LAUSANNE, SWITZERLAND : 1996) 2020; 402:126279. [PMID: 32834760 PMCID: PMC7363609 DOI: 10.1016/j.cej.2020.126279] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/10/2020] [Accepted: 07/12/2020] [Indexed: 05/07/2023]
Abstract
In this work, the degradation of hydroxychloroquine (HCQ) drug in aqueous solution by electrochemical advanced oxidation processes including electrochemical oxidation (EO) using boron doped diamond (BDD) and its combination with UV irradiation (photo-assisted electrochemical oxidation, PEO) and sonication (sono-assisted electrochemical oxidation, SEO) was investigated. EO using BDD anode achieved the complete depletion of HCQ from aqueous solutions in regardless of HCQ concentration, current density, and initial pH value. The decay of HCQ was more rapid than total organic carbon (TOC) indicating that the degradation of HCQ by EO using BDD anode involves successive steps leading to the formation of organic intermediates that end to mineralize. Furthermore, the results demonstrated the release chloride (Cl-) ions at the first stages of HCQ degradation. In addition, the organic nitrogen was converted mainly into NO3 - and NH4 + and small amounts of volatile nitrogen species (NH3 and NOx). Chromatography analysis confirmed the formation of 7-chloro-4-quinolinamine (CQLA), oxamic and oxalic acids as intermediates of HCQ degradation by EO using BDD anode. The combination of EO with UV irradiation or sonication enhances the kinetics and the efficacy of HCQ oxidation. PEO requires the lowest energy consumption (EC) of 63 kWh/m3 showing its cost-effectiveness. PEO has the potential to be an excellent alternative method for the treatment of wastewaters contaminated with HCQ drug and its derivatives.
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Affiliation(s)
- Nasr Bensalah
- Department of Chemistry and Earth Sciences, College of Arts and Science, Qatar University, PO Box 2713 Doha, Qatar
| | - Sondos Midassi
- Department of Chemistry, Faculty of Sciences of Gabes, University of Gabes, Gabes 6072, Tunisia
| | - Mohammad I Ahmad
- Central Laboratories Unit, Qatar University, PO Box 2713 Doha, Qatar
| | - Ahmed Bedoui
- Department of Chemistry, Faculty of Sciences of Gabes, University of Gabes, Gabes 6072, Tunisia
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Mineralization versus fermentation: evidence for two distinct anaerobic bacterial degradation pathways for dichloromethane. ISME JOURNAL 2020; 14:959-970. [PMID: 31907367 DOI: 10.1038/s41396-019-0579-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 12/11/2019] [Accepted: 12/17/2019] [Indexed: 01/03/2023]
Abstract
Dichloromethane (DCM) is an anthropogenic pollutant with ozone destruction potential that is also formed naturally. Under anoxic conditions, fermentation of DCM to acetate and formate has been reported in axenic culture Dehalobacterium formicoaceticum, and to acetate, H2 and CO2 in mixed culture RM, which harbors the DCM degrader 'Candidatus Dichloromethanomonas elyunquensis'. RM cultures produced 28.1 ± 2.3 μmol of acetate from 155.6 ± 9.3 μmol DCM, far less than the one third (i.e., about 51.9 µmol) predicted based on the assumed fermentation model, and observed in cultures of Dehalobacterium formicoaceticum. Temporal metabolite analyses using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy revealed that no 13C-labeled acetate was formed in 13C-DCM-grown RM cultures, indicating acetate was not a direct product of DCM metabolism. The data were reconciled with DCM mineralization and H2 consumption via CO2 reduction to acetate and methane by homoacetogenic and methanogenic partner populations, respectively. In contrast, Dehalobacterium formicoaceticum produced 13C-labeled acetate and formate from 13C-DCM, consistent with a fermentation pathway. Free energy change calculations predicted that organisms with the mineralization pathway are the dominant DCM consumers in environments with H2 <100 ppmv. These findings have implications for carbon and electron flow in environments where DCM is introduced through natural production processes or anthropogenic activities.
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Li Q, Borge R, Sarwar G, de la Paz D, Gantt B, Domingo J, Cuevas CA, Saiz-Lopez A. Impact of halogen chemistry on summertime air quality in coastal and continental Europe: application of the CMAQ model and implications for regulation. ATMOSPHERIC CHEMISTRY AND PHYSICS 2019; 19:15321-15337. [PMID: 32425994 PMCID: PMC7232855 DOI: 10.5194/acp-19-15321-2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Halogen (Cl, Br, and I) chemistry has been reported to influence the formation of secondary air pollutants. Previous studies mostly focused on the impact of chlorine species on air quality over large spatial scales. Very little attention has been paid to the effect of the combined halogen chemistry on air quality over Europe and its implications for control policy. In the present study, we apply a widely used regional model, the Community Multiscale Air Quality Modeling System (CMAQ), incorporated with the latest halogen sources and chemistry, to simulate the abundance of halogen species over Europe and to examine the role of halogens in the formation of secondary air pollution. The results suggest that the CMAQ model is able to reproduce the level of O3, NO2, and halogen species over Europe. Chlorine chemistry slightly increases the levels of OH, HO2, NO3, O3, and NO2 and substantially enhances the level of the Cl radical. Combined halogen chemistry induces complex effects on OH (ranging from -0.023 to 0.030 pptv) and HO2 (in the range of -3.7 to 0.73 pptv), significantly reduces the concentrations of NO3 (as much as 20 pptv) and O3 (as much as 10 ppbv), and decreases NO2 in highly polluted regions (as much as 1.7 ppbv); it increases NO2 (up to 0.20 ppbv) in other areas. The maximum effects of halogen chemistry occur over oceanic and coastal regions, but some noticeable impacts also occur over continental Europe. Halogen chemistry affects the number of days exceeding the European Union target threshold for the protection of human beings and vegetation from ambient O3. In light of the significant impact of halogen chemistry on air quality, we recommend that halogen chemistry be considered for inclusion in air quality policy assessments, particularly in coastal cities.
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Affiliation(s)
- Qinyi Li
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid 28006, Spain
| | - Rafael Borge
- Environmental Modelling Laboratory, Department of Chemical & Environmental Engineering, Universidad Politécnica de Madrid (UPM), Madrid, Spain
| | - Golam Sarwar
- National Exposure Research Laboratory, Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - David de la Paz
- Environmental Modelling Laboratory, Department of Chemical & Environmental Engineering, Universidad Politécnica de Madrid (UPM), Madrid, Spain
| | - Brett Gantt
- Office of Air Quality Planning and Standards, Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jessica Domingo
- Environmental Modelling Laboratory, Department of Chemical & Environmental Engineering, Universidad Politécnica de Madrid (UPM), Madrid, Spain
| | - Carlos A. Cuevas
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid 28006, Spain
| | - Alfonso Saiz-Lopez
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid 28006, Spain
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Clapp CE, Anderson JG. Modeling the Effect of Potential Nitric Acid Removal During Convective Injection of Water Vapor Over the Central United States on the Chemical Composition of the Lower Stratosphere. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:9743-9770. [PMID: 31763110 PMCID: PMC6853249 DOI: 10.1029/2018jd029703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 07/30/2019] [Accepted: 08/04/2019] [Indexed: 06/10/2023]
Abstract
Tropopause-penetrating convection is a frequent seasonal feature of the Central United States climate. This convection presents the potential for consistent transport of water vapor into the upper troposphere and lower stratosphere (UTLS) through the lofting of ice, which then sublimates. Water vapor enhancements associated with convective ice lofting have been observed in both in situ and satellite measurements. These water vapor enhancements can increase the probability of sulfate aerosol-catalyzed heterogeneous reactions that convert reservoir chlorine (HCl and ClONO2) to free radical chlorine (Cl and ClO) that leads to catalytic ozone loss. In addition to water vapor transport, lofted ice may also scavenge nitric acid and further impact the chlorine activation chemistry of the UTLS. We present a photochemical model that resolves the vertical chemical structure of the UTLS to explore the effect of water vapor enhancements and potential additional nitric acid removal. The model is used to define the response of stratospheric column ozone to the range of convective water vapor transported and the temperature variability of the lower stratosphere currently observed over the Central United States in conjunction with potential nitric acid removal and to scenarios of elevated sulfate aerosol surface area density representative of possible future volcanic eruptions or solar radiation management. We find that the effect of HNO3 removal is dependent on the magnitude of nitric acid removal and has the greatest potential to increase chlorine activation and ozone loss under UTLS conditions that weakly favor the chlorine activation heterogeneous reactions by reducing NOx sources.
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Affiliation(s)
- C. E. Clapp
- Department of Chemistry and Chemical BiologyHarvard UniversityCambridgeMAUSA
| | - J. G. Anderson
- Department of Chemistry and Chemical BiologyHarvard UniversityCambridgeMAUSA
- Harvard John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeMAUSA
- Department of Earth and Planetary SciencesHarvard UniversityCambridgeMAUSA
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11
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Hossaini R, Atlas E, Dhomse SS, Chipperfield MP, Bernath PF, Fernando AM, Mühle J, Leeson AA, Montzka SA, Feng W, Harrison JJ, Krummel P, Vollmer MK, Reimann S, O'Doherty S, Young D, Maione M, Arduini J, Lunder CR. Recent Trends in Stratospheric Chlorine From Very Short-Lived Substances. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:2318-2335. [PMID: 30984484 PMCID: PMC6446807 DOI: 10.1029/2018jd029400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 01/02/2019] [Accepted: 01/08/2019] [Indexed: 05/15/2023]
Abstract
Very short-lived substances (VSLS), including dichloromethane (CH2Cl2), chloroform (CHCl3), perchloroethylene (C2Cl4), and 1,2-dichloroethane (C2H4Cl2), are a stratospheric chlorine source and therefore contribute to ozone depletion. We quantify stratospheric chlorine trends from these VSLS (VSLCltot) using a chemical transport model and atmospheric measurements, including novel high-altitude aircraft data from the NASA VIRGAS (2015) and POSIDON (2016) missions. We estimate VSLCltot increased from 69 (±14) parts per trillion (ppt) Cl in 2000 to 111 (±22) ppt Cl in 2017, with >80% delivered to the stratosphere through source gas injection, and the remainder from product gases. The modeled evolution of chlorine source gas injection agrees well with historical aircraft data, which corroborate reported surface CH2Cl2 increases since the mid-2000s. The relative contribution of VSLS to total stratospheric chlorine increased from ~2% in 2000 to ~3.4% in 2017, reflecting both VSLS growth and decreases in long-lived halocarbons. We derive a mean VSLCltot growth rate of 3.8 (±0.3) ppt Cl/year between 2004 and 2017, though year-to-year growth rates are variable and were small or negative in the period 2015-2017. Whether this is a transient effect, or longer-term stabilization, requires monitoring. In the upper stratosphere, the modeled rate of HCl decline (2004-2017) is -5.2% per decade with VSLS included, in good agreement to ACE satellite data (-4.8% per decade), and 15% slower than a model simulation without VSLS. Thus, VSLS have offset a portion of stratospheric chlorine reductions since the mid-2000s.
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Affiliation(s)
- Ryan Hossaini
- Lancaster Environment CentreLancaster UniversityLancasterUK
| | - Elliot Atlas
- Rosenstiel School of Marine and Atmospheric Science (RSMAS)University of MiamiCoral GablesFLUSA
| | | | | | - Peter F. Bernath
- Department of Chemistry and BiochemistryOld Dominion UniversityNorfolkVAUSA
- Department of ChemistryUniversity of WaterlooWaterlooONCanada
| | | | - Jens Mühle
- Scripps Institution of OceanographyUniversity of California San DiegoLa JollaCAUSA
| | | | | | - Wuhu Feng
- School of Earth and EnvironmentUniversity of LeedsLeedsUK
- NCASUniversity of LeedsLeedsUK
| | - Jeremy J. Harrison
- Department of Physics and AstronomyUniversity of LeicesterLeicesterUK
- National Centre for Earth ObservationUniversity of LeicesterLeicesterUK
| | - Paul Krummel
- Climate Science CentreCSIRO Oceans and AtmosphereAspendaleVictoriaAustralia
| | - Martin K. Vollmer
- Laboratory for Air Pollution and Environmental TechnologyEmpa, Swiss Federal Laboratories for Materials Science and TechnologyDuebendorfSwitzerland
| | - Stefan Reimann
- Laboratory for Air Pollution and Environmental TechnologyEmpa, Swiss Federal Laboratories for Materials Science and TechnologyDuebendorfSwitzerland
| | | | - Dickon Young
- School of ChemistryUniversity of BristolBristolUK
| | - Michela Maione
- Department of Pure and Applied SciencesUniversity of UrbinoUrbinoItaly
| | - Jgor Arduini
- Department of Pure and Applied SciencesUniversity of UrbinoUrbinoItaly
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12
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Ruan M, Hou H, Wang B, Li W, Chen Y, Deng X, Zuo X. Computational study on the hydrolysis of halomethanes. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2389-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Detecting recovery of the stratospheric ozone layer. Nature 2018; 549:211-218. [PMID: 28905899 DOI: 10.1038/nature23681] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/31/2017] [Indexed: 11/09/2022]
Abstract
As a result of the 1987 Montreal Protocol and its amendments, the atmospheric loading of anthropogenic ozone-depleting substances is decreasing. Accordingly, the stratospheric ozone layer is expected to recover. However, short data records and atmospheric variability confound the search for early signs of recovery, and climate change is masking ozone recovery from ozone-depleting substances in some regions and will increasingly affect the extent of recovery. Here we discuss the nature and timescales of ozone recovery, and explore the extent to which it can be currently detected in different atmospheric regions.
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14
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Fate of Chloromethanes in the Atmospheric Environment: Implications for Human Health, Ozone Formation and Depletion, and Global Warming Impacts. TOXICS 2017; 5:toxics5040023. [PMID: 29051455 PMCID: PMC5750551 DOI: 10.3390/toxics5040023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/14/2017] [Accepted: 09/15/2017] [Indexed: 11/16/2022]
Abstract
Among the halogenated hydrocarbons, chloromethanes (i.e., methyl chloride, CH₃Cl; methylene chloride, CH₂Cl₂; chloroform, CHCl₃; and carbon tetrachloride, CCl₄) play a vital role due to their extensive uses as solvents and chemical intermediates. This article aims to review their main chemical/physical properties and commercial/industrial uses, as well as the environment and health hazards posed by them and their toxic decomposition products. The environmental properties (including atmospheric lifetime, radiative efficiency, ozone depletion potential, global warming potential, photochemical ozone creation potential, and surface mixing ratio) of these chlorinated methanes are also reviewed. In addition, this paper further discusses their atmospheric fates and human health implications because they are apt to reside in the lower atmosphere when released into the environment. According to the atmospheric degradation mechanism, their toxic degradation products in the troposphere include hydrogen chloride (HCl), carbon monoxide (CO), chlorine (Cl₂), formyl chloride (HCOCl), carbonyl chloride (COCl₂), and hydrogen peroxide (H₂O₂). Among them, COCl₂ (also called phosgene) is a powerful irritating gas, which is easily hydrolyzed or thermally decomposed to form hydrogen chloride.
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15
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Hossaini R, Chipperfield MP, Montzka SA, Leeson AA, Dhomse SS, Pyle JA. The increasing threat to stratospheric ozone from dichloromethane. Nat Commun 2017; 8:15962. [PMID: 28654085 PMCID: PMC5490265 DOI: 10.1038/ncomms15962] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 05/16/2017] [Indexed: 11/29/2022] Open
Abstract
It is well established that anthropogenic chlorine-containing chemicals contribute to ozone layer depletion. The successful implementation of the Montreal Protocol has led to reductions in the atmospheric concentration of many ozone-depleting gases, such as chlorofluorocarbons. As a consequence, stratospheric chlorine levels are declining and ozone is projected to return to levels observed pre-1980 later this century. However, recent observations show the atmospheric concentration of dichloromethane—an ozone-depleting gas not controlled by the Montreal Protocol—is increasing rapidly. Using atmospheric model simulations, we show that although currently modest, the impact of dichloromethane on ozone has increased markedly in recent years and if these increases continue into the future, the return of Antarctic ozone to pre-1980 levels could be substantially delayed. Sustained growth in dichloromethane would therefore offset some of the gains achieved by the Montreal Protocol, further delaying recovery of Earth’s ozone layer. Chlorine-containing species deplete stratospheric ozone and while chlorofluorocarbons have been drastically reduced, dichloromethane concentrations have recently increased rapidly. Hossaini et al. show that continued growth at this rate could result in important delays to Antarctic ozone recovery.
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Affiliation(s)
- Ryan Hossaini
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Martyn P Chipperfield
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.,National Centre for Earth Observation, University of Leeds, Leeds LS2 9JT, UK
| | - Stephen A Montzka
- National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, USA
| | - Amber A Leeson
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Sandip S Dhomse
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.,National Centre for Earth Observation, University of Leeds, Leeds LS2 9JT, UK
| | - John A Pyle
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.,National Centre for Atmospheric Science, University of Cambridge, Cambridge CB2 1EW, UK
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16
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Evidence for strong, widespread chlorine radical chemistry associated with pollution outflow from continental Asia. Sci Rep 2016; 6:36821. [PMID: 27845366 PMCID: PMC5109052 DOI: 10.1038/srep36821] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 10/21/2016] [Indexed: 11/08/2022] Open
Abstract
The chlorine radical is a potent atmospheric oxidant, capable of perturbing tropospheric oxidative cycles normally controlled by the hydroxyl radical. Significantly faster reaction rates allow chlorine radicals to expedite oxidation of hydrocarbons, including methane, and in polluted environments, to enhance ozone production. Here we present evidence, from the CARIBIC airborne dataset, for extensive chlorine radical chemistry associated with Asian pollution outflow, from airborne observations made over the Malaysian Peninsula in winter. This region is known for persistent convection that regularly delivers surface air to higher altitudes and serves as a major transport pathway into the stratosphere. Oxidant ratios inferred from hydrocarbon relationships show that chlorine radicals were regionally more important than hydroxyl radicals for alkane oxidation and were also important for methane and alkene oxidation (>10%). Our observations reveal pollution-related chlorine chemistry that is both widespread and recurrent, and has implications for tropospheric oxidizing capacity, stratospheric composition and ozone chemistry.
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17
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Habartová A, Hormain L, Pluhařová E, Briquez S, Monnerville M, Toubin C, Roeselová M. Molecular Simulations of Halomethanes at the Air/Ice Interface. J Phys Chem A 2015; 119:10052-9. [PMID: 26334558 DOI: 10.1021/acs.jpca.5b06071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Halogenated organics are emitted into the atmosphere from a variety of sources of both natural and anthropogenic origin. Their uptake at the surface of aerosols can affect their reactivity, for example, in processes that take part in ozone destruction due to production of reactive chlorine, bromine, and iodine radicals. Classical molecular dynamics (MD) simulations are carried out to investigate the interaction of small halomethane molecules of atmospheric relevance with a crystalline ice surface. The following halomethanes were studied: CH3Cl, CH2Cl2, CHCl3, CH3Br, CH2Br2, and CHBr3. MD simulations provide an invaluable insight into the adsorption behavior of halomethanes species. The adsorption energy is increasing as the number of halogen atoms is increasing. Moreover, brominated methanes exhibit a stronger interaction with the ice than their chlorinated analogs. Implications for the atmospheric chemistry are discussed.
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Affiliation(s)
- A Habartová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - L Hormain
- PhLAM Laboratory, UMR CNRS 8523, Université de Lille , Cité Scientifique, 59655 Villeneuve d'Ascq, France
| | - E Pluhařová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, 16610 Prague 6, Czech Republic.,Department of Chemistry, École Normale Supérieure, UMR ENS-CNRS-UPMC 8640 , 24 rue Lhomond, 75005 Paris, France
| | - S Briquez
- PhLAM Laboratory, UMR CNRS 8523, Université de Lille , Cité Scientifique, 59655 Villeneuve d'Ascq, France
| | - M Monnerville
- PhLAM Laboratory, UMR CNRS 8523, Université de Lille , Cité Scientifique, 59655 Villeneuve d'Ascq, France
| | - C Toubin
- PhLAM Laboratory, UMR CNRS 8523, Université de Lille , Cité Scientifique, 59655 Villeneuve d'Ascq, France
| | - M Roeselová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, 16610 Prague 6, Czech Republic
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