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Seltzer AM, Shackleton SA, Bourg IC. Solubility Equilibrium Isotope Effects of Noble Gases in Water: Theory and Observations. J Phys Chem B 2023; 127:9802-9812. [PMID: 37937341 DOI: 10.1021/acs.jpcb.3c05651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
The abundance and isotopic composition of noble gases dissolved in water have many applications in the geosciences. In recent years, new analytical techniques have opened the door to the use of high-precision measurements of noble gas isotopes as tracers for groundwater hydrology, oceanography, mantle geochemistry, and paleoclimatology. These analytical advances have brought about new measurements of solubility equilibrium isotope effects (SEIEs) in water (i.e., the relative solubilities of noble gas isotopes) and their sensitivities to the temperature and salinity. Here, we carry out a suite of classical molecular dynamics (MD) simulations and employ the theoretical method of quantum correction to estimate SEIEs for comparison with experimental observations. We find that classical MD simulations can accurately predict SEIEs for the isotopes of Ar, Kr, and Xe to order 0.01‰, on the scale of analytical uncertainty. However, MD simulations consistently overpredict the SEIEs of Ne and He by up to 40% of observed values. We carry out sensitivity tests at different temperatures, salinities, and pressures and employ different sets of interatomic potential parameters and water models. For all noble gas isotopes, the TIP4P water model is found to reproduce observed SEIEs more accurately than the SPC/E and TIP4P/ice models. Classical MD simulations also accurately capture the sign and approximate magnitude of temperature and salinity sensitivities of SEIEs for heavy noble gases. We find that experimental and modeled SEIEs generally follow an inverse-square mass dependence, which implies that the mean-square force experienced by a noble gas atom within a solvation shell is similar for all noble gases. This inverse-square mass proportionality is nearly exact for Ar, Kr, and Xe isotopes, but He and Ne exhibit a slightly weaker mass dependence. We hypothesize that the apparent dichotomy between He-Ne and Ar-Kr-Xe SEIEs may result from atomic size differences, whereby the smaller noble gases are more likely to spontaneously fit within cavities of water without breaking water-water H-bonds, thereby experiencing softer collisions during translation within a solvation shell. We further speculate that the overprediction of simulated He and Ne SEIEs may result from the neglection of higher-order quantum corrections or the overly stiff representation of van der Waals repulsion by the widely used Lennard-Jones 6-12 potential model. We suggest that new measurements of SEIEs of heavy and light noble gases may represent a novel set of constraints with which to refine hydrophobic solvation theories and optimize the set of interatomic potential models used in MD simulations of water and noble gases.
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Affiliation(s)
- Alan M Seltzer
- Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543-1050,United States
| | - Sarah A Shackleton
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544,United States
| | - Ian C Bourg
- Department of Civil and Environmental Engineering (CEE) and High Meadows Environmental Institute (HMEI), Princeton University, Princeton, New Jersey 08544,United States
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At least three xenon binding sites in the glycine binding domain of the N-methyl D-aspartate receptor. Arch Biochem Biophys 2022; 724:109265. [DOI: 10.1016/j.abb.2022.109265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 11/21/2022]
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Owais C, John C, Swathi RS. A swarm intelligence modeling approach reveals noble gas cluster configurations confined within carbon nanotubes. Phys Chem Chem Phys 2020; 22:20693-20703. [PMID: 32901628 DOI: 10.1039/d0cp03014g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Confinement of atoms and molecules brings forth fascinating properties to chemical systems that are otherwise not known in the bulk. Carbon nanotubes (CNTs) and fullerenes are excellent hosts for probing the confinement effects. Herein, we explore the potential energy surfaces of large noble gas clusters, Ngn (Ng = He, Ne and Ar; n = 10, 20, 30, 40, and 50), in the confines of CNTs of various lengths. Our implementation involves integrating the continuum approximation for CNTs with the well-known swarm intelligence technique, particle swarm optimization (PSO), followed by a deterministic local optimization. Global search techniques such as PSO have been increasingly utilized in recent times to track down minimum energy configurations on highly rugged potential energy surfaces. Aside from the position vectors of the noble gas atoms, we have considered the radius of the CNTs as a design variable. Such an approach enabled us to predict the optimal CNT radii for the encapsulation of each of the clusters. Confined cluster geometries ranging from linear, zig-zag, and double-helical to spiral configurations are obtained on encapsulation, in sharp contrast to their bare cluster geometries. On increasing the CNT length, our approach yielded quasi-linear geometries, suggesting that the length of the CNTs plays a crucial role in determining the stable cluster configurations on confinement.
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Affiliation(s)
- Cheriyacheruvakkara Owais
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India.
| | - Chris John
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India.
| | - Rotti Srinivasamurthy Swathi
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India.
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Faure A, Bruzzese L, Steinberg JG, Jammes Y, Torrents J, Berdah SV, Garnier E, Legris T, Loundou A, Chalopin M, Magalon G, Guieu R, Fenouillet E, Lechevallier E. Effectiveness of pure argon for renal transplant preservation in a preclinical pig model of heterotopic autotransplantation. J Transl Med 2016; 14:40. [PMID: 26847569 PMCID: PMC4743167 DOI: 10.1186/s12967-016-0795-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 01/20/2016] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND In kidney transplantation, the conditions of organ preservation following removal influence function recovery. Current static preservation procedures are generally based on immersion in a cold-storage solution used under atmospheric air (approximately 78 kPa N2, 21 kPa O2, 1 kPa Ar). Research on static cold-preservation solutions has stalled, and modifying the gas composition of the storage medium for improving preservation was considered. Organoprotective strategies successfully used noble gases and we addressed here the effects of argon and xenon on graft preservation in an established preclinical pig model of autotransplantation. METHODS The preservation solution Celsior saturated with pure argon (Argon-Celsior) or xenon (Xenon-Celsior) at atmospheric pressure was tested versus Celsior saturated with atmospheric air (Air-Celsior). The left kidney was removed, and Air-Celsior (n = 8 pigs), Argon-Celsior (n = 8) or Xenon-Celsior (n = 6) was used at 4 °C to flush and store the transplant for 30 h, a duration that induced ischemic injury in our model when Air-Celsior was used. Heterotopic autotransplantation and contralateral nephrectomy were performed. Animals were followed for 21 days. RESULTS The use of Argon-Celsior vs. Air-Celsior: (1) improved function recovery as monitored via creatinine clearance, the fraction of excreted sodium and tubulopathy duration; (2) enabled diuresis recovery 2-3 days earlier; (3) improved survival (7/8 vs. 3/8 pigs survived at postoperative day-21); (4) decreased tubular necrosis, interstitial fibrosis, apoptosis and inflammation, and preserved tissue structures as observed after the natural death/euthanasia; (5) stimulated plasma antioxidant defences during the days following transplantation as shown by monitoring the "reduced ascorbic acid/thiobarbituric acid reactive substances" ratio and Hsp27 expression; (6) limited the inflammatory response as shown by expression of TNF-alpha, IL1-beta and IL6 as observed after the natural death/euthanasia. Conversely, Xenon-Celsior was detrimental, no animal surviving by day-8 in a context where functional recovery, renal tissue properties and the antioxidant and inflammation responses were significantly altered. Thus, the positive effects of argon were not attributable to the noble gases as a group. CONCLUSIONS The saturation of Celsior with argon improved early functional recovery, graft quality and survival. Manipulating the gas composition of a preservation medium constitutes therefore a promising approach to improve preservation.
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Affiliation(s)
- Alice Faure
- Department of Urology and Kidney Transplantation, Aix-Marseille University, APHM, Marseille, France.
| | - Laurie Bruzzese
- UMR MD2 & IRBA, Aix-Marseille University, Marseille, France.
| | | | - Yves Jammes
- UMR MD2 & IRBA, Aix-Marseille University, Marseille, France.
| | - Julia Torrents
- Department of Pathology, Aix-Marseille University, APHM, Marseille, France.
| | - Stephane V Berdah
- C.E.R.C, Aix-Marseille University, Faculty of Medicine, Marseille, France.
| | - Emmanuelle Garnier
- C.E.R.C, Aix-Marseille University, Faculty of Medicine, Marseille, France.
| | - Tristan Legris
- Department of Nephrology and Kidney Transplantation, Aix-Marseille University, APHM, Marseille, France.
| | - Anderson Loundou
- Public Health Laboratory, Aix-Marseille University, Marseille, France.
| | - Matthieu Chalopin
- Air Liquide Medical Gases Group, Air Liquide sante International-Claude Delorme Research Center, Jouy-en-Josas, France.
| | - Guy Magalon
- Department of Plastic Surgery, Aix-Marseille University, APHM, Marseille, France.
| | - Regis Guieu
- UMR MD2 & IRBA, Aix-Marseille University, Marseille, France.
| | - Emmanuel Fenouillet
- UMR MD2 & IRBA, Aix-Marseille University, Marseille, France. .,Institut des Sciences Biologiques, CNRS, Paris, France.
| | - Eric Lechevallier
- Department of Urology and Kidney Transplantation, Aix-Marseille University, APHM, Marseille, France.
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Hahn C, Kann ZR, Faust JA, Skinner JL, Nathanson GM. Super-Maxwellian helium evaporation from pure and salty water. J Chem Phys 2016; 144:044707. [PMID: 26827228 DOI: 10.1063/1.4940144] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Helium atoms evaporate from pure water and salty solutions in super-Maxwellian speed distributions, as observed experimentally and modeled theoretically. The experiments are performed by monitoring the velocities of dissolved He atoms that evaporate from microjets of pure water at 252 K and 4-8.5 molal LiCl and LiBr at 232-252 K. The average He atom energies exceed the flux-weighted Maxwell-Boltzmann average of 2RT by 30% for pure water and 70% for 8.5m LiBr. Classical molecular dynamics simulations closely reproduce the observed speed distributions and provide microscopic insight into the forces that eject the He atoms from solution. Comparisons of the density profile and He kinetic energies across the water-vacuum interface indicate that the He atoms are accelerated by He-water collisions within the top 1-2 layers of the liquid. We also find that the average He atom kinetic energy scales with the free energy of solvation of this sparingly soluble gas. This free-energy difference reflects the steeply decreasing potential of mean force on the He atoms in the interfacial region, whose gradient is the repulsive force that tends to expel the atoms. The accompanying sharp decrease in water density suppresses the He-water collisions that would otherwise maintain a Maxwell-Boltzmann distribution, allowing the He atom to escape at high energies. Helium is especially affected by this reduction in collisions because its weak interactions make energy transfer inefficient.
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Affiliation(s)
- Christine Hahn
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA
| | - Zachary R Kann
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA
| | - Jennifer A Faust
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA
| | - J L Skinner
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA
| | - Gilbert M Nathanson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA
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