scholarly journals More than redox, biological organic ligands control iron isotope fractionation in the riparian wetland

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elaheh Lotfi-Kalahroodi ◽  
Anne-Catherine Pierson-Wickmann ◽  
Olivier Rouxel ◽  
Rémi Marsac ◽  
Martine Bouhnik-Le Coz ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Isotope Fractionation ◽  
Isotopic Fractionation ◽  
Isotopic Signature ◽  
Organic Ligands ◽  
Riparian Wetland ◽  
Fe Isotopes ◽  
Preferential Binding ◽  
Isotope Systematics

AbstractAlthough redox reactions are recognized to fractionate iron (Fe) isotopes, the dominant mechanisms controlling the Fe isotope fractionation and notably the role of organic matter (OM) are still debated. Here, we demonstrate how binding to organic ligands governs Fe isotope fractionation beyond that arising from redox reactions. The reductive biodissolution of soil Fe(III) enriched the solution in light Fe isotopes, whereas, with the extended reduction, the preferential binding of heavy Fe isotopes to large biological organic ligands enriched the solution in heavy Fe isotopes. Under oxic conditions, the aggregation/sedimentation of Fe(III) nano-oxides with OM resulted in an initial enrichment of the solution in light Fe isotopes. However, heavy Fe isotopes progressively dominate the solution composition in response to their binding with large biologically-derived organic ligands. Confronted with field data, these results demonstrate that Fe isotope systematics in wetlands are controlled by the OM flux, masking Fe isotope fractionation arising from redox reactions. This work sheds light on an overseen aspect of Fe isotopic fractionation and calls for a reevaluation of the parameters controlling the Fe isotopes fractionation to clarify the interpretation of the Fe isotopic signature.

Fe isotope fractionation between inorganic aqueous Fe(III) and a Fe siderophore complex

2008 ◽  
Vol 72 (1) ◽  
pp. 313-316 ◽  
Author(s):  
K. Dideriksen ◽  
J. A. Baker ◽  
S. L. S. Stipp
Keyword(s):  
Isotopic Composition ◽  
Isotope Fractionation ◽  
Model Compound ◽  
Organic Ligands ◽  
Desferrioxamine B ◽  
Fe Isotopes ◽  
Tracer Experiments

AbstractIn oxic waters, dissolved Fe exists dominantly as Fe(III) complexes with strongly coordinating, siderophore-like ligands. In this study, we have determined an equilibrium Fe isotope fractionation of 0.6% (∆56Fe) between inorganic Fe(III) and Fe(III) siderophore complexes using the siderophore desferrioxamine B as a model compound. The 57Fe tracer experiments show that the Fe isotopes ofthe siderophores exchange readily with dissolved inorganic Fe. The results indicate that organic ligands are likely to be important in the generation ofFe isotope signatures in oxic environments. For example, the isotopic composition ofmarine Fe-Mn nodules may largely be due to the presence of strongly coordinating ligands.

scholarly journals Extreme Zr stable isotope fractionation during magmatic fractional crystallization

2019 ◽  
Vol 5 (12) ◽  
pp. eaax8648 ◽  
Author(s):  
Mauricio Ibañez-Mejia ◽  
François L. H. Tissot
Keyword(s):  
Stable Isotope ◽  
Closed System ◽  
Isotope Fractionation ◽  
Isotope Composition ◽  
Isotopic Fractionation ◽  
Compositional Evolution ◽  
Stable Isotope Fractionation ◽  
Zircon Crystallization ◽  
Single Zircon ◽  
Isotope Systematics

Zirconium is a commonly used elemental tracer of silicate differentiation, yet its stable isotope systematics remain poorly known. Accessory phases rich in Zr4+ such as zircon and baddeleyite may preserve a unique record of Zr isotope behavior in magmatic environments, acting both as potential drivers of isotopic fractionation and recorders of melt compositional evolution. To test this potential, we measured the stable Zr isotope composition of 70 single zircon and baddeleyite crystals from a well-characterized gabbroic igneous cumulate. We show that (i) closed-system magmatic crystallization can fractionate Zr stable isotopes at the >0.5% level, and (ii) zircon and baddeleyite are isotopically heavy relative to the melt from which they crystallize, thus driving chemically differentiated liquids toward isotopically light compositions. Because these effects are contrary to first-order expectations based on mineral-melt bonding environment differences, Zr stable isotope fractionation during zircon crystallization may not solely be a result of closed-system thermodynamic equilibrium.

Anti-toxicant Properties of Saffron and Relevance to Protection from Toxins and Drugs

2020 ◽  
Vol 16 (3) ◽  
pp. 265-283
Author(s):  
Kyriaki Hatziagapiou ◽  
George I. Lambrou
Keyword(s):  
Redox Reactions ◽  
Case Reports ◽  
Meta Analysis ◽  
Reactive Oxygen ◽  
Crocus Sativus ◽  
Protective Effects ◽  
Nitrogen Species ◽  
Eligibility Criteria ◽  
Crocus Sativus L

Background: Reactive oxygen species and reactive nitrogen species, which are collectively called reactive oxygen nitrogen species, are inevitable by-products of cellular metabolic redox reactions, such as oxidative phosphorylation in the mitochondrial respiratory chain, phagocytosis, reactions of biotransformation of exogenous and endogenous substrata in endoplasmic reticulum, eicosanoid synthesis, and redox reactions in the presence of metal with variable valence. Among medicinal plants there is a growing interest in Crocus sativus L. It is a perennial, stemless herb, belonging to Iridaceae family, cultivated in various countries such as Greece, Italy, Spain, Israel, Morocco, Turkey, Iran, India, China, Egypt and Mexico. Objective: The present study aims to address the anti-toxicant role of Crocus sativus L. in the cases of toxin and drug toxification. Materials and Methods: An electronic literature search was conducted by the two authors from 1993 to August 2017. Original articles and systematic reviews (with or without meta-analysis), as well as case reports were selected. Titles and abstracts of papers were screened by a third reviewer to determine whether they met the eligibility criteria, and full texts of the selected articles were retrieved. Results: The authors focused on literature concerning the role of Crocus Sativus L. as an anti-toxicant agent. Literature review showed that Saffron is a potent anti-toxicant agent with a plethora of applications ranging from anti-oxidant properties, to chemotherapy protective effects. Conclusion: Literature findings represented in current review herald promising results for using Crocus Sativus L. and/or its active constituents as anti-toxicant, chemotherapy-induced protection and toxin protection.

scholarly journals The role of His117 in the redox reactions of azurin from Pseudomonas aeruginosa

FEBS Letters ◽  
1996 ◽  
Vol 381 (1-2) ◽  
pp. 140-142 ◽  
Author(s):  
Antonius C.F. Gorren ◽  
Tanneke den Blaauwen ◽  
Gerard W. Canters ◽  
David J. Hopper ◽  
Johannis A. Duine
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Redox Reactions

scholarly journals Technical Note: Evaluation of a low-cost evaporation protection method for portable water samplers

2020 ◽  
Author(s):  
Jana von Freyberg ◽  
Julia L. A. Knapp ◽  
Andrea Rücker ◽  
Bjørn Studer ◽  
James W. Kirchner
Keyword(s):  
Water Samples ◽  
Low Cost ◽  
Isotopic Fractionation ◽  
Field Tests ◽  
Isotopic Signature ◽  
Technical Note ◽  
Stable Water Isotopes ◽  
Sample Collection ◽  
Protection Method ◽  
Cost Efficient

Abstract. Automated field sampling of streamwater or precipitation for subsequent analysis of stable water isotopes (2H and 18O) is often conducted with off-the-shelf automated samplers. However, water samples stored in the field for days and weeks in open bottles inside autosamplers undergo isotopic fractionation and vapor mixing, thus altering their isotopic signature. We therefore designed an evaporation protection method which modifies autosampler bottles using a syringe housing and silicone tube, and tested whether this method reduces evaporative fractionation and vapor mixing in water samples stored for up to 24 days in ISCO autosamplers (Teledyne ISCO., Lincoln, US). Laboratory and field tests under different temperature and humidity conditions showed that water samples in bottles with evaporation protection were far less altered by evaporative fractionation and vapor mixing than samples in conventional open bottles. Our design is a cost-efficient approach to upgrade the 1-litre sample bottles of ISCO 6712 Full-size Portable Samplers, allowing secure water sample collection in warm and dry environments. Our design can be readily adapted (e.g., by using a different syringe size) to fit the bottles used by many other field autosamplers.

The Study on Agricultural Non-Point Nitrogen Pollution Control

2012 ◽  
Vol 573-574 ◽  
pp. 213-217
Author(s):  
Gui Lan Zhang
Keyword(s):  
Pollution Control ◽  
Yellow River ◽  
Control Function ◽  
Nitrogen Pollution ◽  
Natural State ◽  
Runoff Water ◽  
Riparian Wetland ◽  
Temporal And Spatial ◽  
Runoff Events

Purification effects of riparian wetland in a natural state on pollutants are unstable and are always influenced by hydrology, climate, and extent of wetlands development. For this reason, study of the role of the purification function of riparian wetland in a natural state is ongoing. In this study, with the Kouma section of the Yellow River wetlands as the study area, using the field experiment method and the 15N enriched technique, the agricultural non-point nitrogen pollution control function of Phragmites communis Trin in riparian wetlands was studied. Artificial runoff events enabled the collection of a temporal and spatial array of samples within the wetland so that the plume of runoff water moving through the wetland could be traced and its attenuation determined.

scholarly journals Aqueous-based Binary Sulfide Nanoparticle Inks for Cu2ZnSnS4 Thin Films Stabilized with Tin(IV) Chalcogenide Complexes

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1382
Author(s):  
Han Wang ◽  
Amrita Yasin ◽  
Nathaniel Quitoriano ◽  
George Demopoulos
Keyword(s):  
Thin Films ◽  
Nanoparticle Synthesis ◽  
Economic Feasibility ◽  
Organic Ligands ◽  
Sulfur Vapor ◽  
Optical And Electronic Properties ◽  
Photovoltaic Applications ◽  
Deposition Processes ◽  
Czts Thin Films

Cu2ZnSnS4(CZTS) is a promising semiconductor material for photovoltaic applications,with excellent optical and electronic properties while boasting a nontoxic, inexpensive, andabundant elemental composition. Previous high‐quality CZTS thin films often required eithervacuum‐based deposition processes or the use of organic ligands/solvents for ink formulation,which are associated with various issues regarding performance or economic feasibility. To addressthese issues, an alternative method for depositing CZTS thin films using an aqueous‐basednanoparticle suspension is demonstrated in this work. Nanoparticles of constituent binary sulfides(CuxS and ZnS) are stabilized in an ink using tin(IV)‐based, metal chalcogenide complexes such as[Sn2S6]4‐. This research paper provides a systematic study of the nanoparticle synthesis and inkformulation via the enabling role of the tin chalcogenide complexing power, the deposition of highqualityCZTS thin films via spin coating and annealing under sulfur vapor atmosphere, theirstructural characterization in terms of nanocrystal phase, morphology, microstructure, anddensification, and their resultant optoelectronic properties.

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