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Batarchuk V, Shepelytskyi Y, Grynko V, Kovacs AH, Hodgson A, Rodriguez K, Aldossary R, Talwar T, Hasselbrink C, Ruset IC, DeBoef B, Albert MS. Hyperpolarized Xenon-129 Chemical Exchange Saturation Transfer (HyperCEST) Molecular Imaging: Achievements and Future Challenges. Int J Mol Sci 2024; 25:1939. [PMID: 38339217 PMCID: PMC10856220 DOI: 10.3390/ijms25031939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 01/25/2024] [Accepted: 01/28/2024] [Indexed: 02/12/2024] Open
Abstract
Molecular magnetic resonance imaging (MRI) is an emerging field that is set to revolutionize our perspective of disease diagnosis, treatment efficacy monitoring, and precision medicine in full concordance with personalized medicine. A wide range of hyperpolarized (HP) 129Xe biosensors have been recently developed, demonstrating their potential applications in molecular settings, and achieving notable success within in vitro studies. The favorable nuclear magnetic resonance properties of 129Xe, coupled with its non-toxic nature, high solubility in biological tissues, and capacity to dissolve in blood and diffuse across membranes, highlight its superior role for applications in molecular MRI settings. The incorporation of reporters that combine signal enhancement from both hyperpolarized 129Xe and chemical exchange saturation transfer holds the potential to address the primary limitation of low sensitivity observed in conventional MRI. This review provides a summary of the various applications of HP 129Xe biosensors developed over the last decade, specifically highlighting their use in MRI. Moreover, this paper addresses the evolution of in vivo applications of HP 129Xe, discussing its potential transition into clinical settings.
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Affiliation(s)
- Viktoriia Batarchuk
- Chemistry Department, Lakehead University, Thunder Bay, ON P7B 5E1, Canada; (V.B.)
- Thunder Bay Regional Health Research Institute, Thunder Bay, ON P7B 6V4, Canada
| | - Yurii Shepelytskyi
- Chemistry Department, Lakehead University, Thunder Bay, ON P7B 5E1, Canada; (V.B.)
- Thunder Bay Regional Health Research Institute, Thunder Bay, ON P7B 6V4, Canada
| | - Vira Grynko
- Thunder Bay Regional Health Research Institute, Thunder Bay, ON P7B 6V4, Canada
- Chemistry and Materials Science Program, Lakehead University, Thunder Bay, ON P7B 5E1, Canada
| | - Antal Halen Kovacs
- Applied Life Science Program, Lakehead University, Thunder Bay, ON P7B 5E1, Canada
| | - Aaron Hodgson
- Physics Program, Lakehead University, Thunder Bay, ON P7B 5E1, Canada
| | - Karla Rodriguez
- Chemistry Department, Lakehead University, Thunder Bay, ON P7B 5E1, Canada; (V.B.)
| | - Ruba Aldossary
- Thunder Bay Regional Health Research Institute, Thunder Bay, ON P7B 6V4, Canada
| | - Tanu Talwar
- Chemistry Department, Lakehead University, Thunder Bay, ON P7B 5E1, Canada; (V.B.)
| | - Carson Hasselbrink
- Chemistry & Biochemistry Department, California Polytechnic State University, San Luis Obispo, CA 93407-005, USA
| | | | - Brenton DeBoef
- Department of Chemistry, University of Rhode Island, Kingston, RI 02881, USA
| | - Mitchell S. Albert
- Chemistry Department, Lakehead University, Thunder Bay, ON P7B 5E1, Canada; (V.B.)
- Thunder Bay Regional Health Research Institute, Thunder Bay, ON P7B 6V4, Canada
- Faculty of Medical Sciences, Northern Ontario School of Medicine, Thunder Bay, ON P7B 5E1, Canada
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Shepelytskyi Y, Grynko V, Batarchuk V, Hasselbrink CL, Kovacs AH, Ruset IC, Rodriguez K, Al Taradeh N, Talwar T, DeBoef B, Albert MS. R3-Noria-methanesulfonate: A Molecular Cage with Superior Hyperpolarized Xenon-129 MRI Contrast. ACS Sens 2023; 8:4707-4715. [PMID: 38064687 DOI: 10.1021/acssensors.3c01791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Hyperpolarized (HP) xenon-129 (129Xe) magnetic resonance imaging (MRI) has the potential to be used as a molecular imaging modality. For this purpose, numerous supramolecular cages have been developed and evaluated in the past. Herein, we report a novel and unique macrocycle that can be successfully utilized for xenon MRI, the resorcinarene trimer methanesulfonate (R3-Noria-MeSO3H). This molecule is capable of two different contrast mechanisms for xenon-MRI, resulting from an increase in the effective spin-spin relaxation and hyperpolarized chemical exchange saturation transfer (HyperCEST). We have demonstrated a superior negative contrast caused by R3-Noria-MeSO3H on HP 129Xe MRI at 3.0 T as well as HyperCEST imaging of the studied macrocycle. Additionally, we have found that the complex aggregation behaviors of R3-Noria-methanesulfonate and its impact on xenon-129 relaxivity are an area for future study.
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Affiliation(s)
- Yurii Shepelytskyi
- Chemistry Department, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
- Thunder Bay Regional Health Research Institute, 980 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
| | - Vira Grynko
- Thunder Bay Regional Health Research Institute, 980 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
- Chemistry and Materials Science Program, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
| | - Viktoriia Batarchuk
- Chemistry Department, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
- Thunder Bay Regional Health Research Institute, 980 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
| | - Carson L Hasselbrink
- Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Antal H Kovacs
- Applied Life Science Program, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
| | - Iulian C Ruset
- Xemed LCC, 16 Strafford Avenue, Durham, New Hampshire 03824, United States
| | - Karla Rodriguez
- Chemistry Department, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
| | - Nedal Al Taradeh
- Chemistry Department, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
| | - Tanu Talwar
- Chemistry Department, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
| | - Brenton DeBoef
- Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Mitchell S Albert
- Chemistry Department, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
- Thunder Bay Regional Health Research Institute, 980 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
- Northern Ontario School of Medicine, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
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Abstract
Noble gases have well-established biological effects, yet their molecular mechanisms remain poorly understood. Here, we investigated, both experimentally and computationally, the molecular modes of xenon (Xe) action in bacteriophage T4 lysozyme (T4L). By combining indirect gassing methods with a colorimetric lysozyme activity assay, a reversible, Xe-specific (20 ± 3)% inhibition effect was observed. Accelerated molecular dynamic simulations revealed that Xe exerts allosteric inhibition on the protein by expanding a C-terminal hydrophobic cavity. Xe-induced cavity expansion results in global conformational changes, with long-range transduction distorting the active site where peptidoglycan binds. Interestingly, the peptide substrate binding site that enables lysozyme specificity does not change conformation. Two T4L mutants designed to reshape the C-terminal Xe cavity established a correlation between cavity expansion and enzyme inhibition. This work also highlights the use of Xe flooding simulations to identify new cryptic binding pockets. These results enrich our understanding of Xe-protein interactions at the molecular level and inspire further biochemical investigations with noble gases.
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Affiliation(s)
- Jiayi He
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Ivan J Dmochowski
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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Ghanmi C, Nakbi H, Al-Qarni HJ, Alharzali N, Berriche H. Structure, energetics, and spectroscopy of the K 2+(X 2Σ +g) interacting with the noble gas atoms Ar, Kr and Xe. J Mol Graph Model 2023; 120:108413. [PMID: 36758327 DOI: 10.1016/j.jmgm.2023.108413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/31/2022] [Accepted: 01/12/2023] [Indexed: 02/05/2023]
Abstract
The structure, energetic, and spectroscopy properties of the ionic system K2+(X2Σ+g) interacting with the noble gas atoms Argon, Krypton and Xenon are studied. The computations are done by an accurate ab initio approach based on the pseudo-potential technique, Gaussian basis sets, parameterized l-dependent polarization potentials and an analytic potential form for the K+Ar, K+Kr and K+Xe interactions. These interactions are added via the CCSD(T) potential taken from literature and fitted applying the analytical expression of Tang and Toennies. The application of the pseudo-potential approach reduces the number of active electrons of each complex to only one electron. The potential energy surfaces are analyzed on a large range of the Jacobi coordinates, R and θ. By the general interpolation outline based on the RKHS (Reproducing Kernel Hilbert Space) procedure, we have reproduced for each complex from our ab initio results the two-dimensional contour plots of an analytical potential. To evaluate the stability of each complex, we have determined from the potential energy surfaces the equilibrium distance (Re), the well depth (De), the quantum energy (D0), the zero-point-energy (ZPE) and the ZPE%. The results showed that the linear configurations, where the noble gas atom connected to the K2+(X2Σ+g) system, are the more stable.
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Affiliation(s)
- Chedli Ghanmi
- Laboratory of Interfaces and Advanced Materials, Faculty of Science, University of Monastir, 5019, Monastir, Tunisia.
| | - Haifa Nakbi
- Laboratory of Interfaces and Advanced Materials, Faculty of Science, University of Monastir, 5019, Monastir, Tunisia
| | - Hind Jahman Al-Qarni
- Physics Department, College of Science and Arts, Balqarn, Bisha University, Saudi Arabia
| | - Nisrin Alharzali
- Laboratory of Interfaces and Advanced Materials, Faculty of Science, University of Monastir, 5019, Monastir, Tunisia
| | - Hamid Berriche
- Laboratory of Interfaces and Advanced Materials, Faculty of Science, University of Monastir, 5019, Monastir, Tunisia; Mathematics and Natural Sciences Department, School of Arts and Sciences, American University of Ras Al Khaimah, Ras Al Khaimah, United Arab Emirates.
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Schmidt P, Vogel A, Schwarze B, Seufert F, Licha K, Wycisk V, Kilian W, Hildebrand PW, Mitschang L. Towards Probing Conformational States of Y2 Receptor Using Hyperpolarized 129Xe NMR. Molecules 2023; 28:molecules28031424. [PMID: 36771089 PMCID: PMC9919357 DOI: 10.3390/molecules28031424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/20/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
G protein-coupled receptors can adopt many different conformational states, each of them exhibiting different restraints towards downstream signaling pathways. One promising strategy to identify and quantify this conformational landscape is to introduce a cysteine at a receptor site sensitive to different states and label this cysteine with a probe for detection. Here, the application of NMR of hyperpolarized 129Xe for the detection of the conformational states of human neuropeptide Y2 receptor is introduced. The xenon trapping cage molecule cryptophane-A attached to a cysteine in extracellular loop 2 of the receptor facilitates chemical exchange saturation transfer experiments without and in the presence of native ligand neuropeptide Y. High-quality spectra indicative of structural states of the receptor-cage conjugate were obtained. Specifically, five signals could be assigned to the conjugate in the apo form. After the addition of NPY, one additional signal and subtle modifications in the persisting signals could be detected. The correlation of the spectroscopic signals and structural states was achieved with molecular dynamics simulations, suggesting frequent contact between the xenon trapping cage and the receptor surface but a preferred interaction with the bound ligand.
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Affiliation(s)
- Peter Schmidt
- Institute of Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Haertelstrasse 16-18, 04107 Leipzig, Germany
| | - Alexander Vogel
- Institute of Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Haertelstrasse 16-18, 04107 Leipzig, Germany
| | - Benedikt Schwarze
- Institute of Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Haertelstrasse 16-18, 04107 Leipzig, Germany
| | - Florian Seufert
- Institute of Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Haertelstrasse 16-18, 04107 Leipzig, Germany
| | - Kai Licha
- Institute of Chemistry and Biochemistry, Freie Universitaet Berlin, Takustrasse 3, 14195 Berlin, Germany
| | - Virginia Wycisk
- Institute of Chemistry and Biochemistry, Freie Universitaet Berlin, Takustrasse 3, 14195 Berlin, Germany
| | - Wolfgang Kilian
- Physikalisch-Technische Bundesanstalt Braunschweig und Berlin (PTB), Abbestrasse 2-12, 10587 Berlin, Germany
| | - Peter W. Hildebrand
- Institute of Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Haertelstrasse 16-18, 04107 Leipzig, Germany
| | - Lorenz Mitschang
- Physikalisch-Technische Bundesanstalt Braunschweig und Berlin (PTB), Abbestrasse 2-12, 10587 Berlin, Germany
- Correspondence:
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Bryden N, McHugh CT, Kelley M, Branca RT. Longitudinal nuclear spin relaxation of 129 Xe in solution and in hollow fiber membranes at low and high magnetic field strengths. Magn Reson Med 2022; 88:2005-2013. [PMID: 35726363 PMCID: PMC9420755 DOI: 10.1002/mrm.29362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/04/2022] [Accepted: 05/26/2022] [Indexed: 11/12/2022]
Abstract
PURPOSE To measure dissolved-phase 129 Xe T1 values at high and low magnetic fields and the field dependence of 129 Xe depolarization by hollow fiber membranes used to infuse hyperpolarized xenon in solution. METHODS Dissolved-phase T1 measurements were made at 11.7T and 2.1 mT by bubbling xenon in solution and by using a variable delay to allow spins to partially relax back to thermal equilibrium before probing their magnetization. At high field, relaxation values were compared to those obtained by using the small flip angle method. For depolarization studies, we probed the magnetization of the polarized gas diffusing through an exchange membrane module placed at different field strengths. RESULTS Total loss of polarization was observed for xenon diffusing through hollow fiber membranes at low field, while significant polarization loss (>20%) was observed at magnetic fields up to 2T. Dissolved-phase 129 Xe T1 values were found consistently shorter at 2.1 mT compared to 11.7T. In addition, both O2 and Xe gas concentrations in solution were found to significantly affect dissolved-phase 129 Xe T1 values. CONCLUSION Dissolved-phase 129 Xe measurements are feasible at low field, but to assess the feasibility of in vivo dissolved-phase imaging and spectroscopy the T1 of xenon in blood will need to be measured. Both O2 and Xe concentrations in solution are found to greatly affect dissolved-phase 129 Xe T1 values and may explain, along with RF miscalibration, the large discrepancy in previously reported results.
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Affiliation(s)
- Nicholas Bryden
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Christian T McHugh
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Michele Kelley
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Rosa T Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Khan AS, Harvey RL, Birchall JR, Irwin RK, Nikolaou P, Schrank G, Emami K, Dummer A, Barlow MJ, Goodson BM, Chekmenev EY. Enabling Clinical Technologies for Hyperpolarized 129 Xenon Magnetic Resonance Imaging and Spectroscopy. Angew Chem Int Ed Engl 2021; 60:22126-22147. [PMID: 34018297 PMCID: PMC8478785 DOI: 10.1002/anie.202015200] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Indexed: 11/06/2022]
Abstract
Hyperpolarization is a technique that can increase nuclear spin polarization with the corresponding gains in nuclear magnetic resonance (NMR) signals by 4-8 orders of magnitude. When this process is applied to biologically relevant samples, the hyperpolarized molecules can be used as exogenous magnetic resonance imaging (MRI) contrast agents. A technique called spin-exchange optical pumping (SEOP) can be applied to hyperpolarize noble gases such as 129 Xe. Techniques based on hyperpolarized 129 Xe are poised to revolutionize clinical lung imaging, offering a non-ionizing, high-contrast alternative to computed tomography (CT) imaging and conventional proton MRI. Moreover, CT and conventional proton MRI report on lung tissue structure but provide little functional information. On the other hand, when a subject breathes hyperpolarized 129 Xe gas, functional lung images reporting on lung ventilation, perfusion and diffusion with 3D readout can be obtained in seconds. In this Review, the physics of SEOP is discussed and the different production modalities are explained in the context of their clinical application. We also briefly compare SEOP to other hyperpolarization methods and conclude this paper with the outlook for biomedical applications of hyperpolarized 129 Xe to lung imaging and beyond.
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Affiliation(s)
- Alixander S Khan
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Rebecca L Harvey
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Jonathan R Birchall
- Intergrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), 5101 Cass Avenue, Detroit, MI, 48202, USA
| | - Robert K Irwin
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | - Geoffry Schrank
- Northrup Grumman Space Systems, 45101 Warp Drive, Sterling, VA, 20166, USA
| | | | | | - Michael J Barlow
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Boyd M Goodson
- Department of Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL, 62901, USA
- Materials Technology Center, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL, 62901, USA
| | - Eduard Y Chekmenev
- Intergrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), 5101 Cass Avenue, Detroit, MI, 48202, USA
- Russian Academy of Sciences, Leninskiy Prospekt 14, Moscow, 119991, Russia
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Jin J, Li M, Li J, Li B, Duan L, Yang F, Gu N. Xenon Nanobubbles for the Image-Guided Preemptive Treatment of Acute Ischemic Stroke via Neuroprotection and Microcirculatory Restoration. ACS Appl Mater Interfaces 2021; 13:43880-43891. [PMID: 34493044 DOI: 10.1021/acsami.1c06014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Early lesion site diagnosis and neuroprotection are crucial to the theranostics of acute ischemic stroke. Xenon (Xe), as a nontoxic gaseous neuroprotectant, holds great promise for ischemic stroke therapy. In this study, Xe-encapsulated lipid nanobubbles (Xe-NBs) have been prepared for the real-time ultrasound image-guided preemptive treatment of the early stroke. The lipids are self-assembled at the interface of free Xe bubbles, and the mean diameter of Xe-NBs is 225 ± 11 nm with a Xe content of 73 ± 2 μL/mL. The in vitro results show that Xe-NBs can protect oxygen/glucose-deprived PC12 cells against apoptosis and oxidative stress. Based on the ischemic stroke mice model, the biodistribution, timely ultrasound imaging, and the therapeutic effects of Xe-NBs for stroke lesions were investigated in vivo. The accumulation of Xe-NBs to the ischemic lesion endows ultrasound contrast imaging with the lesion area. The cerebral blood flow measurement indicates that the administration of Xe-NBs can improve microcirculatory restoration, resulting in reduced acute microvascular injury in the lesion area. Furthermore, local delivery of therapeutic Xe can significantly reduce the volume of cerebral infarction and restore the neurological function with reduced neuron injury against apoptosis. Therefore, Xe-NBs provide a novel nanosystem for the safe and rapid theranostics of acute ischemic stroke, which is promising to translate into the clinical management of stroke.
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Affiliation(s)
- Juan Jin
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 211166, P. R. China
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Mei Li
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 211166, P. R. China
- The Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, P. R. China
| | - Jing Li
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Bin Li
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Lei Duan
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 211166, P. R. China
| | - Fang Yang
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
| | - Ning Gu
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 211166, P. R. China
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
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Abstract
Noble gas (or aerogen) bond (NgB) can be outlined as the attractive interaction between an electron-rich atom or group of atoms and any element of Group-18 acting as an electron acceptor. The IUPAC already recommended systematic nomenclature for the interactions of groups 17 and 16 (halogen and chalcogen bonds, respectively). Investigations dealing with noncovalent interactions involving main group elements (acting as Lewis acids) have rapidly grown in recent years. They are becoming acting players in essential fields such as crystal engineering, supramolecular chemistry, and catalysis. For obvious reasons, the works devoted to the study of noncovalent Ng-bonding interactions are significantly less abundant than halogen, chalcogen, pnictogen, and tetrel bonding. Nevertheless, in this short review, relevant theoretical and experimental investigations on noncovalent interactions involving Xenon are emphasized. Several theoretical works have described the physical nature of NgB and their interplay with other noncovalent interactions, which are discussed herein. Moreover, exploring the Cambridge Structural Database (CSD) and Inorganic Crystal Structure Database (ICSD), it is demonstrated that NgB interactions are crucial in governing the X-ray packing of xenon derivatives. Concretely, special attention is given to xenon fluorides and xenon oxides, since they exhibit a strong tendency to establish NgBs.
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Affiliation(s)
- Antonio Frontera
- Department of Chemistry, Universitat de les Illes Balears, Crta de valldemossa km 7.5, 07122 Palma de Mallorca (Baleares), Spain
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Jayapaul J, Schröder L. Nanoparticle-Based Contrast Agents for 129Xe HyperCEST NMR and MRI Applications. Contrast Media Mol Imaging 2019; 2019:9498173. [PMID: 31819739 PMCID: PMC6893250 DOI: 10.1155/2019/9498173] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/15/2019] [Indexed: 02/06/2023]
Abstract
Spin hyperpolarization techniques have enabled important advancements in preclinical and clinical MRI applications to overcome the intrinsic low sensitivity of nuclear magnetic resonance. Functionalized xenon biosensors represent one of these approaches. They combine two amplification strategies, namely, spin exchange optical pumping (SEOP) and chemical exchange saturation transfer (CEST). The latter one requires host structures that reversibly bind the hyperpolarized noble gas. Different nanoparticle approaches have been implemented and have enabled molecular MRI with 129Xe at unprecedented sensitivity. This review gives an overview of the Xe biosensor concept, particularly how different nanoparticles address various critical aspects of gas binding and exchange, spectral dispersion for multiplexing, and targeted reporter delivery. As this concept is emerging into preclinical applications, comprehensive sensor design will be indispensable in translating the outstanding sensitivity potential into biomedical molecular imaging applications.
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Affiliation(s)
- Jabadurai Jayapaul
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
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Fgaier S, de Almeida Lopes MM, de Oliveira Silva E, Aarrouf J, Urban L. Xenon lamps used for fruit surface sterilization can increase the content of total flavonols in leaves of Lactuca sativa L. without any negative effect on net photosynthesis. PLoS One 2019; 14:e0223787. [PMID: 31634363 PMCID: PMC6802843 DOI: 10.1371/journal.pone.0223787] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 09/27/2019] [Indexed: 11/18/2022] Open
Abstract
One (1P), two (2P), three (3P) or four (4P) pulses of light supplied by a xenon lamp, were applied to young lettuce plants grown in pots. The lamp used in the trial was similar to those used for fruit surface sterilization. Total flavonols were measured in leaves using the Dualex method. In a first trial conducted in greenhouse conditions, 6 days after the pulsed light (PL) treatment, flavonols were increased by 312% and 525% in the 3P and 4P treatments, respectively, in comparison to the those in the untreated control. Changes in the chlorophyll fluorescence parameters suggest that the PL treatment may induce limited and transient damage to the photosynthetic machinery and that the damage increases with the increasing number of pulses. The performance parameters were not significantly affected by PL and recovered fully by 6 days after the treatments. The 1P and the 2P treatments 6 days after the treatment showed a 28.6% and a 32.5% increase, respectively, in net photosynthetic assimilation, when compared to that of the control. However, 8 days after the treatment, there was no longer a difference between the treatments and the control in net photosynthetic assimilation. Eight days after the light treatment, the 3P treatment showed a 38.4% increase in maximal net photosynthetic assimilation over that of the control, which is an indication of positive long-term adaptation of photosynthetic capacity. As a whole, our observations suggest that PL could be used on field or greenhouse crops to increase their phytochemical content. No long-lasting or strong negative effects on photosynthesis were associated with PL within the range of doses we tested; some observations even suggest that certain treatments could result in an additional positive effect. This conclusion is supported by a second trial conducted in phytotrons. More studies are required to better understand the roles of the different wavelengths supplied by PL and their interactions.
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Affiliation(s)
- Salah Fgaier
- UMR 95 Qualisud/Laboratoire de Physiologie des Fruits et Légumes, Avignon Université, Avignon, France
- NOVAGENETIC, Anjou Actiparc, Longué Jumelle, France
| | | | | | - Jawad Aarrouf
- UMR 95 Qualisud/Laboratoire de Physiologie des Fruits et Légumes, Avignon Université, Avignon, France
| | - Laurent Urban
- UMR 95 Qualisud/Laboratoire de Physiologie des Fruits et Légumes, Avignon Université, Avignon, France
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Mari E, Bousmah Y, Boutin C, Léonce E, Milanole G, Brotin T, Berthault P, Erard M. Bimodal Detection of Proteins by 129 Xe NMR and Fluorescence Spectroscopy. Chembiochem 2019; 20:1450-1457. [PMID: 30650230 DOI: 10.1002/cbic.201800802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Indexed: 11/10/2022]
Abstract
A full understanding of biological phenomena involves sensitive and noninvasive detection. Herein, we report the optimization of a probe for intracellular proteins that combines the advantages of fluorescence and hyperpolarized 129 Xe NMR spectroscopy detection. The fluorescence detection part is composed of six residues containing a tetracysteine tag (-CCXXCC-) genetically incorporated into the protein of interest and of a small organic molecule, CrAsH. CrAsH becomes fluorescent if it binds to the tetracysteine tag. The part of the biosensor that enables detection by means of 129 Xe NMR spectroscopy, which is linked to the CrAsH moiety by a spacer, is based on a cryptophane core that is fully suited to reversibly host xenon. Three different peptides, containing the tetracysteine tag and four organic biosensors of different stereochemistry, are benchmarked to propose the best couple that is fully suited for the in vitro detection of proteins.
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Affiliation(s)
- Emilie Mari
- NIMBE, CEA, CNRS, Université de Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
- Laboratoire de Chimie Physique, CNRS, Université Paris-Sud, Université Paris-Saclay, Batiment 349, 91405, Orsay, France
| | - Yasmina Bousmah
- Laboratoire de Chimie Physique, CNRS, Université Paris-Sud, Université Paris-Saclay, Batiment 349, 91405, Orsay, France
| | - Céline Boutin
- NIMBE, CEA, CNRS, Université de Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
| | - Estelle Léonce
- NIMBE, CEA, CNRS, Université de Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
| | - Gaelle Milanole
- SCBM, Université Paris-Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
| | - Thierry Brotin
- Université Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR 5182, Université Lyon 1, Laboratoire de Chimie, 46 allée d'Italie, 69364, Lyon, France
| | - Patrick Berthault
- NIMBE, CEA, CNRS, Université de Paris Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
| | - Marie Erard
- Laboratoire de Chimie Physique, CNRS, Université Paris-Sud, Université Paris-Saclay, Batiment 349, 91405, Orsay, France
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Winkler DA, Katz I, Farjot G, Warden AC, Thornton AW. Decoding the Rich Biological Properties of Noble Gases: How Well Can We Predict Noble Gas Binding to Diverse Proteins? ChemMedChem 2018; 13:1931-1938. [PMID: 30003691 DOI: 10.1002/cmdc.201800434] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Indexed: 12/19/2022]
Abstract
The chemically inert noble gases display a surprisingly rich spectrum of useful biological properties. Relatively little is known about the molecular mechanisms behind these effects. It is clearly not feasible to conduct large numbers of pharmacological experiments on noble gases to identify activity. Computational studies of the binding of noble gases and proteins can address this paucity of information and provide insight into mechanisms of action. We used bespoke computational grid calculations to predict the positions of energy minima in the interactions of noble gases with diverse proteins. The method was validated by quantifying how well simulations could predict binding positions in 131 diverse protein X-ray structures containing 399 Xe and Kr atoms. We found excellent agreement between calculated and experimental binding positions of noble gases. 94 % of all crystallographic xenon atoms were within 1 Xe van der Waals (vdW) diameter of a predicted binding site, and 97 % lay within 2 vdW diameters. 100 % of crystallographic krypton atoms were within 1 Kr vdW diameter of a predicted binding site. We showed the feasibility of large-scale computational screening of all ≈60 000 unique structures in the Protein Data Bank. This will elucidate biochemical mechanisms by which these novel 'atomic drugs' elicit their valuable biochemical properties and identify new medical uses.
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Affiliation(s)
- David A Winkler
- Manufacturing Business Unit, CSIRO, Bayview Avenue, Clayton, 3168, Australia
- Biochemistry and Genetics, La Trobe University, Kingsbury Drive, Bundoora, 3086, Australia
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Australia
| | - Ira Katz
- Early Drug Development, Air Liquide Santé International, Centre de Recherche Paris-Saclay, Jouy-en-Josas, France
- Department of Mechanical Engineering, Lafayette College, Easton, PA, USA
| | - Géraldine Farjot
- Early Drug Development, Air Liquide Santé International, Centre de Recherche Paris-Saclay, Jouy-en-Josas, France
| | - Andrew C Warden
- Manufacturing Business Unit, CSIRO, Bayview Avenue, Clayton, 3168, Australia
| | - Aaron W Thornton
- Manufacturing Business Unit, CSIRO, Bayview Avenue, Clayton, 3168, Australia
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Döpfert J, Schnurr M, Kunth M, Rose HM, Hennig A, Schröder L. Time-resolved monitoring of enzyme activity with ultrafast Hyper-CEST spectroscopy. Magn Reson Chem 2018; 56:679-688. [PMID: 29274298 DOI: 10.1002/mrc.4702] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/07/2017] [Accepted: 12/10/2017] [Indexed: 06/07/2023]
Abstract
We propose a method to dynamically monitor the progress of an enzymatic reaction using NMR of hyperpolarized 129 Xe in a host-guest system. It is based on a displacement assay originally designed for fluorescence experiments that exploits the competitive binding of the enzymatic product on the one hand and a reporter dye on the other hand to a supramolecular host. Recently, this assay has been successfully transferred to NMR, using xenon as a reporter, cucurbit[6]uril as supramolecular host, and chemical exchange saturation transfer with hyperpolarized Xe (Hyper-CEST) as detection technique. Its advantage is that the enzyme acts on the unmodified substrate and that only the product is detected through immediate inclusion into the host. We here apply a method that drastically accelerates the acquisition of Hyper-CEST spectra in vitro using magnetic field gradients. This allows monitoring the dynamic progress of the conversion of lysine to cadaverine with a temporal resolution of ~30 s. Moreover, the method only requires to sample the very early onset of the reaction (<0.5% of substrate conversion where the host itself is required only at μM concentrations) at comparatively low reaction rates, thus saving enzyme material and reducing NMR acquisition time. The obtained value for the specific activity agrees well with previously published results from fluorescence assays. We furthermore outline how the Hyper-CEST results correlate with xenon T2 measurements performed during the enzymatic reaction. This suggests that ultrafast Hyper-CEST spectroscopy can be used for dynamically monitoring enzymatic activity with NMR.
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Affiliation(s)
- Jörg Döpfert
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Matthias Schnurr
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Martin Kunth
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Honor May Rose
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Andreas Hennig
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
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15
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Burant A, Antonacci M, McCallister D, Zhang L, Branca RT. Effects of superparamagnetic iron oxide nanoparticles on the longitudinal and transverse relaxation of hyperpolarized xenon gas. J Magn Reson 2018; 291:53-62. [PMID: 29702362 PMCID: PMC5975651 DOI: 10.1016/j.jmr.2018.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/26/2018] [Accepted: 04/04/2018] [Indexed: 06/08/2023]
Abstract
SuperParamagnetic Iron Oxide Nanoparticles (SPIONs) are often used in magnetic resonance imaging experiments to enhance Magnetic Resonance (MR) sensitivity and specificity. While the effect of SPIONs on the longitudinal and transverse relaxation time of 1H spins has been well characterized, their effect on highly diffusive spins, like those of hyperpolarized gases, has not. For spins diffusing in linear magnetic field gradients, the behavior of the magnetization is characterized by the relative size of three length scales: the diffusion length, the structural length, and the dephasing length. However, for spins diffusing in non-linear gradients, such as those generated by iron oxide nanoparticles, that is no longer the case, particularly if the diffusing spins experience the non-linearity of the gradient. To this end, 3D Monte Carlo simulations are used to simulate the signal decay and the resulting image contrast of hyperpolarized xenon gas near SPIONs. These simulations reveal that signal loss near SPIONs is dominated by transverse relaxation, with little contribution from T1 relaxation, while simulated image contrast and experiments show that diffusion provides no appreciable sensitivity enhancement to SPIONs.
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Affiliation(s)
- Alex Burant
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, USA; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, USA
| | - Michael Antonacci
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, USA; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, USA
| | - Drew McCallister
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, USA; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, USA
| | - Le Zhang
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, USA; Department of Applied Physical Science, University of North Carolina at Chapel Hill, USA
| | - Rosa Tamara Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, USA; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, USA.
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Klegerman ME, Moody MR, Hurling JR, Peng T, Huang SL, McPherson DD. Gas chromatography/mass spectrometry measurement of xenon in gas-loaded liposomes for neuroprotective applications. Rapid Commun Mass Spectrom 2017; 31:1-8. [PMID: 27689777 PMCID: PMC5154815 DOI: 10.1002/rcm.7749] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 09/16/2016] [Accepted: 09/25/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE We have produced a liposomal formulation of xenon (Xe-ELIP) as a neuroprotectant for inhibition of brain damage in stroke patients. This mandates development of a reliable assay to measure the amount of dissolved xenon released from Xe-ELIP in water and blood samples. METHODS Gas chromatography/mass spectrometry (GC/MS) was used to quantify xenon gas released into the headspace of vials containing Xe-ELIP samples in water or blood. In order to determine blood concentration of xenon in vivo after Xe-ELIP administration, 6 mg of Xe-ELIP lipid was infused intravenously into rats. Blood samples were drawn directly from a catheterized right carotid artery. After introduction of the samples, each vial was allowed to equilibrate to 37°C in a water bath, followed by 20 minutes of sonication prior to headspace sampling. Xenon concentrations were calculated from a gas dose-response curve and normalized using the published xenon water-gas solubility coefficient. RESULTS The mean corrected percent of xenon from Xe-ELIP released into water was 3.87 ± 0.56% (SD, n = 8), corresponding to 19.3 ± 2.8 μL/mg lipid, which is consistent with previous independent Xe-ELIP measurements. The corresponding xenon content of Xe-ELIP in rat blood was 23.38 ± 7.36 μL/mg lipid (n = 8). Mean rat blood xenon concentration after intravenous administration of Xe-ELIP was 14 ± 10 μM, which is approximately 15% of the estimated neuroprotective level. CONCLUSIONS Using this approach, we have established a reproducible method for measuring dissolved xenon in fluids. These measurements have established that neuroprotective effects can be elicited by less than 20% of the calculated neuroprotective xenon blood concentration. More work will have to be done to establish the protective xenon pharmacokinetic range. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Melvin E. Klegerman
- University of Texas Health Science Center - Houston, Department of Internal Medicine, Division of Cardiovascular Medicine, 1941 East Road, Houston, Texas 77054, U.S.A
| | - Melanie R. Moody
- University of Texas Health Science Center - Houston, Department of Internal Medicine, Division of Cardiovascular Medicine, 1941 East Road, Houston, Texas 77054, U.S.A
| | - Jermaine R. Hurling
- University of Texas Health Science Center - Houston, Department of Internal Medicine, Division of Cardiovascular Medicine, 1941 East Road, Houston, Texas 77054, U.S.A
| | - Tao Peng
- University of Texas Health Science Center - Houston, Department of Internal Medicine, Division of Cardiovascular Medicine, 1941 East Road, Houston, Texas 77054, U.S.A
| | - Shao-Ling Huang
- University of Texas Health Science Center - Houston, Department of Internal Medicine, Division of Cardiovascular Medicine, 1941 East Road, Houston, Texas 77054, U.S.A
| | - David D. McPherson
- University of Texas Health Science Center - Houston, Department of Internal Medicine, Division of Cardiovascular Medicine, 1941 East Road, Houston, Texas 77054, U.S.A
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Sauguet L, Fourati Z, Prangé T, Delarue M, Colloc'h N. Structural Basis for Xenon Inhibition in a Cationic Pentameric Ligand-Gated Ion Channel. PLoS One 2016; 11:e0149795. [PMID: 26910105 PMCID: PMC4765991 DOI: 10.1371/journal.pone.0149795] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/04/2016] [Indexed: 12/15/2022] Open
Abstract
GLIC receptor is a bacterial pentameric ligand-gated ion channel whose action is inhibited by xenon. Xenon has been used in clinical practice as a potent gaseous anaesthetic for decades, but the molecular mechanism of interactions with its integral membrane receptor targets remains poorly understood. Here we characterize by X-ray crystallography the xenon-binding sites within both the open and "locally-closed" (inactive) conformations of GLIC. Major binding sites of xenon, which differ between the two conformations, were identified in three distinct regions that all belong to the trans-membrane domain of GLIC: 1) in an intra-subunit cavity, 2) at the interface between adjacent subunits, and 3) in the pore. The pore site is unique to the locally-closed form where the binding of xenon effectively seals the channel. A putative mechanism of the inhibition of GLIC by xenon is proposed, which might be extended to other pentameric cationic ligand-gated ion channels.
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Affiliation(s)
- Ludovic Sauguet
- Unité de Dynamique Structurale des Macromolécules (UMR 3528 CNRS) Institut Pasteur, Paris, France
| | - Zeineb Fourati
- Unité de Dynamique Structurale des Macromolécules (UMR 3528 CNRS) Institut Pasteur, Paris, France
| | - Thierry Prangé
- Laboratoire de cristallographie et RMN biologiques (UMR 8015 CNRS), Paris, France
| | - Marc Delarue
- Unité de Dynamique Structurale des Macromolécules (UMR 3528 CNRS) Institut Pasteur, Paris, France
- * E-mail:
| | - Nathalie Colloc'h
- CNRS, UMR 6301, ISTCT CERVOxy group, GIP Cyceron, Caen, France
- UNICAEN, Normandie Univ., UMR 6301 ISTCT, Caen, France
- CEA, DSV/I2BM, UMR 6301 ISTCT, Caen, France
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18
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Al-Gharabli S, Engeßer P, Gera D, Klein S, Oppenländer T. Engineering of a highly efficient Xe₂*-excilamp (xenon excimer lamp, λmax=172 nm, η=40%) and qualitative comparison to a low-pressure mercury lamp (LP-Hg, λ=185/254 nm) for water purification. Chemosphere 2016; 144:811-815. [PMID: 26414741 DOI: 10.1016/j.chemosphere.2015.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 09/02/2015] [Accepted: 09/05/2015] [Indexed: 06/05/2023]
Abstract
Excilamps are mercury-free gas-discharge sources of non-coherent VUV or UV radiation with high radiant power and a long lifetime. The most efficient excilamp that is currently available on the market is a VUV xenon excilamp system (Xe2(*)-excimer lamp, λ(max) = 172 nm) with a stated radiant efficiency η of 40% at an electrical input power P(el) of 20 W, 50 W or 100 W. In this paper, the use of this highly efficient Xe2(*)-excilamp (P(el) = 20 W) for water treatment is demonstrated using a recirculating laboratory photoreactor system with negative radiation geometry. The efficiency in the 172 nm initiated bleaching of aqueous solutions of Rhodamine B is compared to that initiated by a common low-pressure mercury (LP-Hg) lamp (185 nm, TNN 15/32). The dependence of the pseudo zero order rate constant k´ of decolorization of RhB on the flow rate and on the initial concentration of RhB was investigated. Both lamps exhibited dependences of k´ on the initial concentration of RhB, which represents a typical saturation kinetical behavior. The saturation kinetics was very prominent in the case of the Xe2(*)-excilamp. Also, the Xe2(*)-excilamp treatment exhibited a significant influence on the flow rate of the RhB aqueous solution, which was not the case during the LP-Hg lamp initiated bleaching of RhB. The results of this paper demonstrate that Xe2(*)-excilamps can be used for VUV-initiated water purification. However, to reach the maximum efficacy of the Xe2(*)-excilamp for photo-initiated water purification further engineering optimization of the photoreactor concept is necessary.
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Affiliation(s)
- Samer Al-Gharabli
- German Jordanian University, Chemical-Pharmaceutical Engineering Department, School of Applied Medical Sciences, 35247, Amman, 11180, Jordan.
| | - Patrick Engeßer
- Hochschule Furtwangen University, Campus Villingen-Schwenningen, Jakob-Kienzle-Str. 17, 78054 Villingen-Schwenningen, Germany
| | - Diana Gera
- Hochschule Furtwangen University, Campus Villingen-Schwenningen, Jakob-Kienzle-Str. 17, 78054 Villingen-Schwenningen, Germany
| | - Sandra Klein
- Hochschule Furtwangen University, Campus Villingen-Schwenningen, Jakob-Kienzle-Str. 17, 78054 Villingen-Schwenningen, Germany
| | - Thomas Oppenländer
- Hochschule Furtwangen University, Campus Villingen-Schwenningen, Jakob-Kienzle-Str. 17, 78054 Villingen-Schwenningen, Germany.
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Thomae R, Conradie J, Fourie D, Mira J, Nemulodi F, Kuechler D, Toivanen V. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS. Rev Sci Instrum 2016; 87:02A731. [PMID: 26931949 DOI: 10.1063/1.4935630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.
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Affiliation(s)
- R Thomae
- iThemba LABS, P.O. Box 722, Somerset West 7130, South Africa
| | - J Conradie
- iThemba LABS, P.O. Box 722, Somerset West 7130, South Africa
| | - D Fourie
- iThemba LABS, P.O. Box 722, Somerset West 7130, South Africa
| | - J Mira
- iThemba LABS, P.O. Box 722, Somerset West 7130, South Africa
| | - F Nemulodi
- iThemba LABS, P.O. Box 722, Somerset West 7130, South Africa
| | - D Kuechler
- CERN, BE/ABP/HSL, 1211 Geneva 23, Switzerland
| | - V Toivanen
- CERN, BE/ABP/HSL, 1211 Geneva 23, Switzerland
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Abstract
Neutron diffraction measurements demonstrate that hydrostatic pressure promotes liquid-ordered (Lo) domain formation in lipid membranes prepared as both oriented multilayers and unilamellar vesicles made of a canonical ternary lipid mixture for which demixing transitions have been extensively studied. The results demonstrate an unusually large dependence of the mixing transition on hydrostatic pressure. Additionally, data at 28 °C show that the magnitude of increase in Lo caused by 10 MPa pressure is much the same as the decrease in Lo produced by twice minimum alveolar concentrations (MAC) of general anesthetics such as halothane, nitrous oxide, and xenon. Therefore, the results may provide a plausible explanation for the reversal of general anesthesia by hydrostatic pressure.
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Affiliation(s)
- David L Worcester
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg 20899, Maryland, United States
- Department of Physiology and Biophysics, University of California , Irvine 92697, California, United States
| | - Michael Weinrich
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg 20899, Maryland, United States
- Eunice Kennedy Shriver National Center of Child Health and Human Development, National Institutes of Health , 31 Center Drive, Bethesda 20892, Maryland, United States
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Shishova NV, Fesenko EE. [Prospects for Application of Gases and Gas Hydrates to Cryopreservation]. Biofizika 2015; 60:947-974. [PMID: 26591607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In the present review, we tried to evaluate the known properties of gas hydrates and gases participating in the formation of gas hydrates from the point of view of the mechanisms of cryoinjury and cryoprotection, to consider the papers on freezing biological materials in the presence of inert gases, and to analyze the perspectives for the development of this direction. For the purpose, we searched for the information on the physical properties of gases and gas hydrates, compared processes occured during the formation of gas hydrates and water ice, analyzed the influence of the formation and growth of gas hydrates on the structure of biological objects. We prepared a short review on the biological effects of xenon, krypton, argon, carbon dioxide, hydrogen sulfide, and carbon monoxide especially on hypothermal conditions and probable application of these properties in cryopreservation technologies. The description of the existing experiments on cryopreservation of biological objects with the use of gases was analyzed. On the basis of the information we found, the most perspective directions of work in the field of cryopreservation of biological objects with the use of gases were outlined. An attempt was made to forecast the potential problems in this field.
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Teng F, Liu Z, Zhang A, Li M. Photocatalytic Performances of Ag3PO4 Polypods for Degradation of Dye Pollutant under Natural Indoor Weak Light Irradiation. Environ Sci Technol 2015; 49:9489-9494. [PMID: 25807447 DOI: 10.1021/acs.est.5b00735] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
It is still a big challenge for Ag3PO4 to be applied in practice mainly because of its low stability resistant to photo corrosion, although it is an efficient photocatalyst. Herein, we have mainly investigated its activity and stability under indoor weak light for the degradation of dye pollutants. It is amazing that under indoor weak light irradiation, rhodamine B (RhB) can be completely degraded by Ag3PO4 polypods after 36 h, but only 18% of RhB by N-doped TiO2 after 120 h. It is found that under indoor weak light irradiation, the degradation rate (0.08099 h(-1)) of RhB over Ag3PO4 polypods are 46 times higher than that (0.00173 h(-1)) of N-doped TiO2. The high activity of Ag3PO4 polypods are mainly attributed to the three-dimensional branched nanostructure and high-energy {110} facets exposed. After three cycles, surprisingly, Ag3PO4 polypods show a high stability under indoor weak light irradiation, whereas Ag3PO4 have been decomposed into Ag under visible light irradiation with an artificial Xe light source. This natural weak light irradiation strategy could be a promising method for the other unstable photocatalysts in the degradation of environmental pollutants.
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Abstract
A lack of molecular contrast agents has slowed the application of ultrasensitive hyperpolarized (129)Xe NMR methods. Here, we report that commercially available cucurbit[6]uril (CB[6]) undergoes rapid xenon exchange kinetics at 300 K, and is detectable by Hyper-CEST NMR at 1.8 pM in PBS and at 1 μM in human plasma where many molecules, including polyamines, can compete with xenon for CB[6] binding.
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Affiliation(s)
- Yanfei Wang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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Laptev DS, Polezhaeva TV, Zaitseva OO, Khudyakov AN, Utemov SV, Knyazev MG, Kostyaev AA. [Effect of inert gas xenon on the functional state of nucleated cells of peripheral blood during freezing]. Fiziol Cheloveka 2015; 41:109-112. [PMID: 26027341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A new method of preservation of nucleated cells in the electric refrigerator with xenon. After slow freezing and storage is even one day at -80 °C persists for more than 60% leukocytes. Cell membranes are resistant to the vital dye. In 85% of granulocytes stored baseline lysosomal-cationic protein, reduced lipid peroxidation and antioxidant activity. Cryopreservation of biological objects in inert gases is a promising direction in the practice of medicine and can be an alternative to the traditional method using liquid nitrogen.
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Darkhalil ID, Paquet C, Waqas M, Gounev TK, Durig JR. Conformational stability, r(0) structural parameters, vibrational assignments and ab initio calculations of ethyldichlorophosphine. Spectrochim Acta A Mol Biomol Spectrosc 2015; 136 Pt A:42-50. [PMID: 24618201 DOI: 10.1016/j.saa.2014.01.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 01/07/2014] [Accepted: 01/09/2014] [Indexed: 06/03/2023]
Abstract
Variable temperature (-60 to -100 °C) studies of ethyldichlorophosphine, CH3CH2PCl2, of the infrared spectra (4000-400 cm(-1)) dissolved in liquid xenon have been carried out. From these data, the two conformers have been identified and the enthalpy difference has been determined between the more stable trans conformer and the less stable gauche form to be 88±9 cm(-1) (1.04±0.11 kJ/mol). The percentage of abundance of the gauche conformer is estimated to be 57% at ambient temperature. The conformational stabilities have been predicted from ab initio calculations by utilizing many different basis sets up to aug-cc-pVTZ for both MP2(full) and density functional theory calculations by the B3LYP method. Vibrational assignments have been provided for both conformers which have been predicted by MP2(full)/6-31G(d) ab initio calculations to predict harmonic force fields, wavenumbers of the fundamentals, infrared intensities, Raman activities and depolarization ratios for both conformers. Estimated r0 structural parameters have been obtained from adjusted MP2(full)/6-311+G(d,p) calculations. The results are discussed and compared to the corresponding properties of some related molecules.
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Affiliation(s)
- Ikhlas D Darkhalil
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Charles Paquet
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Mohammad Waqas
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Todor K Gounev
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - James R Durig
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
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Ünsalan O, Kuş N, Jarmelo S, Fausto R. Trans- and cis-stilbene isolated in cryogenic argon and xenon matrices. Spectrochim Acta A Mol Biomol Spectrosc 2015; 136 Pt A:81-94. [PMID: 24211173 DOI: 10.1016/j.saa.2013.10.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 08/30/2013] [Accepted: 10/10/2013] [Indexed: 06/02/2023]
Abstract
Monomers of trans- (TS) and cis-stilbene (CS) were isolated in cryogenic argon and xenon matrices, and their infrared (IR) spectra were fully assigned and interpreted. The interpretation of the vibrational spectra received support from theoretical calculations undertaken at the DFT(B3LYP)/6-311++G(d,p) level of theory. In situ broadband UV irradiation of the matrix-isolated CS led to its isomerization to TS, which appeared in the photolysed matrices in both non-planar and planar configurations. The non-planar species was found to convert into the more stable planar form upon subsequent annealing of the matrices at higher temperature. TS was found to be photostable under the used experimental conditions. The structure of the non-planar TS form was assigned based on the comparison of its observed IR spectrum with those theoretically predicted for different conformations of TS. Chemometrics was used to make this assignment. Additional reasoning on the structure of the studied stilbenes is presented taking as basis results of the Natural Bond Orbital analysis.
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Affiliation(s)
- Ozan Ünsalan
- Department of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal; Department of Physics, Faculty of Sciences, University of Istanbul, Turkey
| | - Nihal Kuş
- Department of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal; Department of Physics, Anadolu University, Eskişehir, Turkey
| | - Susana Jarmelo
- Department of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal
| | - Rui Fausto
- Department of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal.
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27
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Durig JR, Klaassen JJ, Sawant DK, Deodhar BS, Panikar SS, Gurusinghe RM, Darkhalil ID, Tubergen MJ. Microwave, structural, conformational, vibrational studies and ab initio calculations of isocyanocyclopentane. Spectrochim Acta A Mol Biomol Spectrosc 2015; 136 Pt A:3-15. [PMID: 24480667 DOI: 10.1016/j.saa.2013.12.078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Revised: 12/08/2013] [Accepted: 12/09/2013] [Indexed: 06/03/2023]
Abstract
The infrared and Raman spectra (3200-50 cm(-1)) of the gas, liquid or solution, and solid have been recorded of isocyanocyclopentane, c-C5H9NC. FT-microwave studies have also been carried out and 23 transitions were recorded for the envelope-axial (Ax) conformer. Variable temperature (-65 to -100 °C) studies of the infrared spectra (3200-400 cm(-1)) dissolved in liquid xenon have been carried out. From these data, both the Ax and envelope-equatorial (Eq) conformers have been identified and their relative stabilities obtained. The enthalpy difference has been determined to be 102±10 cm(-1) (1.21±0.11 kJ mol(-1)) with the Ax conformer the more stable form. The percentage of the Eq conformer is estimated to be 38±1% at ambient temperature. The conformational stabilities have been predicted from ab initio calculations by utilizing several different basis sets up to aug-cc-pVTZ from both MP2(full) and density functional theory calculations by the B3LYP method. Vibrational assignments have been made for the observed bands for both conformers with initial predictions by MP2(full)/6-31G(d) ab initio calculations to obtain harmonic force constants, wavenumbers, infrared intensities, Raman activities and depolarization ratios for both conformers. The structural parameter values for the Ax form are; for the heavy atom distances (Å): C≡N = 1.176 (3); Cα-N=1.432 (3); Cα-Cβ,Cβ'=1.534 (3); Cβ-Cγ,Cγ'=1.542 (3); Cγ-Cγ'=1.554 (3) and angles (°):∠Cα-N≡C=177.8 (5); ∠CβCα-N=110.4 (5); <CβCαCβ' = 102.9 (5); ∠CαCβCγ=103.6 (5); <CβCγCγ' = 105.9 (5). The results are discussed and compared to the corresponding properties of some related molecules.
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Affiliation(s)
- James R Durig
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
| | - Joshua J Klaassen
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Dattatray K Sawant
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Bhushan S Deodhar
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Savitha S Panikar
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | | | - Ikhlas D Darkhalil
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110, USA
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Borocci S, Cecchi P, Giordani M, Grandinetti F. Complexes of the noble gases with H3O+: a theoretical investigation on Ng(H3O+) (Ng = He-Xe). Eur J Mass Spectrom (Chichester) 2015; 21:171-181. [PMID: 26307697 DOI: 10.1255/ejms.1354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The geometries, harmonic vibrational frequencies, and binding energies (Bes) of the Ng(H(3)O(+)) complexes (Ng = He-Xe) were investigated at the coupled cluster level of theory, and their bonding situation was assayed by various methods of bonding analysis. The effects of Ng on H(3)O(+) progressively increase from He to Xe, and only He can be regarded as an essentially "innocent" ligand. The binding energies also increase in the same periodic order, and are by far dominated by the "noncovalent" ion-induced dipole interaction arising from the H(3)O(+)-induced polarization of Ng. For Ne, Ar, Kr, and Xe, this term has a larger contribution from the p orbital lying on the bond axis, and two smaller contributions from the p orbitals perpendicular to the bond axis. For the heaviest Ar(H(3)O(+)), Kr(H(3)O(+)), and Xe(H(3)O(+)), BE also has a "covalent" component, which is ascribed to the relatively-appreciable charge transfer from Ng to H(3)O(+).
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Affiliation(s)
- Stefano Borocci
- Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali (DIBAF), Università della Tuscia, L.go dell'Università, s.n.c., 01100 Viterbo, Italy. Istituto per le Metodologie Chimiche del CNR, Via Salaria, Km 29.500, 00015, Monterotondo, RM, Italy.
| | - Patrizio Cecchi
- Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali (DIBAF), Università della Tuscia, L.go dell'Università, s.n.c., 01100 Viterbo, Italy.
| | - Maria Giordani
- Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali (DIBAF), Università della Tuscia, L.go dell'Università, s.n.c., 01100 Viterbo, Italy. Istituto per le Metodologie Chimiche del CNR, Via Salaria, Km 29.500, 00015, Monterotondo, RM, Italy.
| | - Felice Grandinetti
- Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali (DIBAF), Università della Tuscia, L.go dell'Università, s.n.c., 01100 Viterbo, Italy. Istituto per le Metodologie Chimiche del CNR, Via Salaria, Km 29.500, 00015, Monterotondo, RM, Italy.
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Juranić PN, Stepanov A, Ischebeck R, Schlott V, Pradervand C, Patthey L, Radović M, Gorgisyan I, Rivkin L, Hauri CP, Monoszlai B, Ivanov R, Peier P, Liu J, Togashi T, Owada S, Ogawa K, Katayama T, Yabashi M, Abela R. High-precision x-ray FEL pulse arrival time measurements at SACLA by a THz streak camera with Xe clusters. Opt Express 2014; 22:30004-12. [PMID: 25606930 DOI: 10.1364/oe.22.030004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The accurate measurement of the arrival time of a hard X-ray free electron laser (FEL) pulse with respect to a laser is of utmost importance for pump-probe experiments proposed or carried out at FEL facilities around the world. This manuscript presents the latest device to meet this challenge, a THz streak camera using Xe gas clusters, capable of pulse arrival time measurements with an estimated accuracy of several femtoseconds. An experiment performed at SACLA demonstrates the performance of the device at photon energies between 5 and 10 keV with variable photon beam parameters.
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Nikolaou P, Coffey AM, Barlow MJ, Rosen MS, Goodson BM, Chekmenev EY. Temperature-ramped (129)Xe spin-exchange optical pumping. Anal Chem 2014; 86:8206-12. [PMID: 25008290 PMCID: PMC4139178 DOI: 10.1021/ac501537w] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 06/26/2014] [Indexed: 12/12/2022]
Abstract
We describe temperature-ramped spin-exchange optical pumping (TR-SEOP) in an automated high-throughput batch-mode (129)Xe hyperpolarizer utilizing three key temperature regimes: (i) "hot"-where the (129)Xe hyperpolarization rate is maximal, (ii) "warm"-where the (129)Xe hyperpolarization approaches unity, and (iii) "cool"-where hyperpolarized (129)Xe gas is transferred into a Tedlar bag with low Rb content (<5 ng per ∼1 L dose) suitable for human imaging applications. Unlike with the conventional approach of batch-mode SEOP, here all three temperature regimes may be operated under continuous high-power (170 W) laser irradiation, and hyperpolarized (129)Xe gas is delivered without the need for a cryocollection step. The variable-temperature approach increased the SEOP rate by more than 2-fold compared to the constant-temperature polarization rate (e.g., giving effective values for the exponential buildup constant γSEOP of 62.5 ± 3.7 × 10(-3) min(-1) vs 29.9 ± 1.2 × 10(-3) min(-1)) while achieving nearly the same maximum %PXe value (88.0 ± 0.8% vs 90.1% ± 0.8%, for a 500 Torr (67 kPa) Xe cell loading-corresponding to nuclear magnetic resonance/magnetic resonance imaging (NMR/MRI) enhancements of ∼3.1 × 10(5) and ∼2.32 × 10(8) at the relevant fields for clinical imaging and HP (129)Xe production of 3 T and 4 mT, respectively); moreover, the intercycle "dead" time was also significantly decreased. The higher-throughput TR-SEOP approach can be implemented without sacrificing the level of (129)Xe hyperpolarization or the experimental stability for automation-making this approach beneficial for improving the overall (129)Xe production rate in clinical settings.
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Affiliation(s)
- Panayiotis Nikolaou
- Department
of Radiology, Vanderbilt University Institute of Imaging
Science, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Aaron M. Coffey
- Department
of Radiology, Vanderbilt University Institute of Imaging
Science, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Biomedical
Engineering, Department of Biochemistry, and Vanderbilt-Ingram
Cancer Center, Vanderbilt University, Nashville, Tennessee 37205, United States
| | - Michael J. Barlow
- Sir Peter Mansfield
Magnetic Resonance Centre, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Matthew S. Rosen
- Athinoula A. Martinos
Center for Biomedical Imaging, Massachusetts General
Hospital, Boston, Massachusetts 02129, United States
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Boyd M. Goodson
- Department
of Chemistry and Biochemistry, Southern
Illinois University, Carbondale, Illinois 62901, United States
| | - Eduard Y. Chekmenev
- Department
of Radiology, Vanderbilt University Institute of Imaging
Science, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Biomedical
Engineering, Department of Biochemistry, and Vanderbilt-Ingram
Cancer Center, Vanderbilt University, Nashville, Tennessee 37205, United States
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Dawid A, Górny K, Wojcieszyk D, Dendzik Z, Gburski Z. Collision-induced light scattering in a thin xenon layer between graphite slabs - MD study. Spectrochim Acta A Mol Biomol Spectrosc 2014; 129:594-600. [PMID: 24755364 DOI: 10.1016/j.saa.2014.03.101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 03/14/2014] [Accepted: 03/22/2014] [Indexed: 06/03/2023]
Abstract
The collision-induced light scattering many-body correlation functions and their spectra in thin xenon layer located between two parallel graphite slabs have been investigated by molecular dynamics computer simulations. The results have been obtained at three different distances (densities) between graphite slabs. Our simulations show the increased intensity of the interaction-induced light scattering spectra at low frequencies for xenon atoms in confined space, in comparison to the bulk xenon sample. Moreover, we show substantial dependence of the interaction-induced light scattering correlation functions of xenon on the distances between graphite slabs. The dynamics of xenon atoms in a confined space was also investigated by calculating the mean square displacement functions and related diffusion coefficients. The structural property of confined xenon layer was studied by calculating the density profile, perpendicular to the graphite slabs. Building of a fluid phase of xenon in the innermost part of the slot was observed. The nonlinear dependence of xenon diffusion coefficient on the separation distance between graphite slabs has been found.
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Affiliation(s)
- A Dawid
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland.
| | - K Górny
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
| | - D Wojcieszyk
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Z Dendzik
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Z Gburski
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
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Thevis M, Piper T, Geyer H, Thomas A, Schaefer MS, Kienbaum P, Schänzer W. Measuring xenon in human plasma and blood by gas chromatography/mass spectrometry. Rapid Commun Mass Spectrom 2014; 28:1501-1506. [PMID: 24861600 DOI: 10.1002/rcm.6926] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 04/16/2014] [Accepted: 04/17/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE Due to the favorable pharmacokinetic properties and minimal side effects of xenon, its use in modern anesthesia has been well accepted, and recent studies further demonstrated the intra- and postoperative neuro-, cardio-, and reno-protective action of the noble gas. Since the production of the hypoxia-inducible factor 1α (HIF-1α) and its downstream effector erythropoietin as well as noradrenalin reuptake inhibition have been found to play key roles in this context, the question arose as to whether the use of xenon is a matter for doping controls and preventive doping research. The aim of the present study was hence to evaluate whether the (ab)use of xenon can be detected from doping control samples with the instrumentation commonly available in sports drug testing laboratories. METHODS Plasma was saturated with xenon according to reported protocols, and the target analyte was measured by means of gas chromatography/time-of-flight and triple quadrupole mass spectrometry with headspace injection. Recording the accurate mass of three major xenon isotopes at m/z 128.9048, 130.9045 and 131.9042 allowed for the unequivocal identification of the analyte and the detection assay was characterized concerning limit of detection (LOD), intraday precision, and specificity as well as analyte recovery under different storage conditions. RESULTS Xenon was detected in fortified plasma samples with detection limits of approximately 0.5 nmol/mL to 50 nmol/mL, depending on the type of mass spectrometer used. The method characteristics of intraday precision (coefficient of variation <20%) and specificity demonstrated the fitness-for-purpose of the analytical approach to unambiguously detect xenon at non-physiological concentrations in human plasma and blood. Eventually, authentic plasma and blood samples collected pre-, intra-, and post-operative (4, 8, and 24 h) were positively analyzed after storage for up to 30 h, and provided proof-of-concept for the developed assay. CONCLUSIONS If relevant to doping controls, xenon can be determined from plasma and blood samples, i.e. common specimens of routine sports drug testing in the context of Athlete Biological Passport (ABP) analyses. Optimization of sampling and analytical procedures will allow the detection limit to be further improved and potentially enable accurate quantification of the anesthetic agent.
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Affiliation(s)
- Mario Thevis
- Center for Preventive Doping Research - Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany; European Monitoring Center for Emerging Doping Agents (EuMoCEDA), Cologne/Bonn, Germany
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Thompson AE, Meredig B, Wolverton C. An improved interatomic potential for xenon in UO2: a combined density functional theory/genetic algorithm approach. J Phys Condens Matter 2014; 26:105501. [PMID: 24553248 DOI: 10.1088/0953-8984/26/10/105501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We have created an improved xenon interatomic potential for use with existing UO2 potentials. This potential was fit to density functional theory calculations with the Hubbard U correction (DFT + U) using a genetic algorithm approach called iterative potential refinement (IPR). We examine the defect energetics of the IPR-fitted xenon interatomic potential as well as other, previously published xenon potentials. We compare these potentials to DFT + U derived energetics for a series of xenon defects in a variety of incorporation sites (large, intermediate, and small vacant sites). We find the existing xenon potentials overestimate the energy needed to add a xenon atom to a wide set of defect sites representing a range of incorporation sites, including failing to correctly rank the energetics of the small incorporation site defects (xenon in an interstitial and xenon in a uranium site neighboring uranium in an interstitial). These failures are due to problematic descriptions of Xe-O and/or Xe-U interactions of the previous xenon potentials. These failures are corrected by our newly created xenon potential: our IPR-generated potential gives good agreement with DFT + U calculations to which it was not fitted, such as xenon in an interstitial (small incorporation site) and xenon in a double Schottky defect cluster (large incorporation site). Finally, we note that IPR is very flexible and can be applied to a wide variety of potential forms and materials systems, including metals and EAM potentials.
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Affiliation(s)
- Alexander E Thompson
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
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Ohkura Y, Weisse JM, Cai L, Zheng X. Flash ignition of freestanding porous silicon films: effects of film thickness and porosity. Nano Lett 2013; 13:5528-5533. [PMID: 24175629 DOI: 10.1021/nl403114g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report the first successful xenon flash ignition of freestanding porous Si films in air. The minimum flash ignition energy (Emin) first decreases and then increases with increasing the porous Si film thickness due to the competition between light absorption and heat loss. The Emin is lower for higher porosity film because high porosity reduces both the heat capacity and the thermal conductivity, facilitating the temperature rise. These results are important for initiating controlled porous Si combustion and preventing their unwanted combustion for safety reasons.
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Affiliation(s)
- Yuma Ohkura
- Department of Mechanical Engineering, Stanford University , Stanford, California 94305, United States
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Tanwar AS, Goyal VD, Choudhary D, Panjikar S, Anand R. Importance of hydrophobic cavities in allosteric regulation of formylglycinamide synthetase: insight from xenon trapping and statistical coupling analysis. PLoS One 2013; 8:e77781. [PMID: 24223728 PMCID: PMC3815217 DOI: 10.1371/journal.pone.0077781] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 09/12/2013] [Indexed: 11/19/2022] Open
Abstract
Formylglycinamide ribonucleotide amidotransferase (FGAR-AT) is a 140 kDa bi-functional enzyme involved in a coupled reaction, where the glutaminase active site produces ammonia that is subsequently utilized to convert FGAR to its corresponding amidine in an ATP assisted fashion. The structure of FGAR-AT has been previously determined in an inactive state and the mechanism of activation remains largely unknown. In the current study, hydrophobic cavities were used as markers to identify regions involved in domain movements that facilitate catalytic coupling and subsequent activation of the enzyme. Three internal hydrophobic cavities were located by xenon trapping experiments on FGAR-AT crystals and further, these cavities were perturbed via site-directed mutagenesis. Biophysical characterization of the mutants demonstrated that two of these three voids are crucial for stability and function of the protein, although being ∼20 Å from the active centers. Interestingly, correlation analysis corroborated the experimental findings, and revealed that amino acids lining the functionally important cavities form correlated sets (co-evolving residues) that connect these regions to the amidotransferase active center. It was further proposed that the first cavity is transient and allows for breathing motion to occur and thereby serves as an allosteric hotspot. In contrast, the third cavity which lacks correlated residues was found to be highly plastic and accommodated steric congestion by local adjustment of the structure without affecting either stability or activity.
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Affiliation(s)
- Ajay Singh Tanwar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, India
| | - Venuka Durani Goyal
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, India
| | - Deepanshu Choudhary
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, India
| | - Santosh Panjikar
- Australian Synchrotron, Clayton, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
| | - Ruchi Anand
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, India
- * E-mail:
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Mizuno N, Makino M, Kumasaka T. A convenient tool for gas derivatization using fine-needle capillary mounting for protein crystals. J Synchrotron Radiat 2013; 20:999-1002. [PMID: 24121356 PMCID: PMC3795572 DOI: 10.1107/s0909049513021584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/02/2013] [Indexed: 06/02/2023]
Abstract
Gas derivatization of protein crystals is useful not only to analyse gas-binding proteins but also to solve the phase problem of X-ray crystallography by using noble gases. However, the gas pressurization tools for these experiments are often elaborate and need to release the gas before flash-cooling. To simplify this step, a procedure using a fine-needle capillary to mount and flash-cool protein crystals under the pressurization of gases has been developed. After the crystals are picked up with the capillary, the capillary is sealed with an adhesive and then connected directly to a gas regulator. The quality of the diffraction data using this method is comparable with that of data from conventional pressurization procedures. The preparation of xenon-derivatives of hen egg-white lysozyme using this method was a success. In the derivatives, two new xenon binding sites were found and one of their sites vanished by releasing the gas. This observation shows the availability of flash-cooling under gas pressurization. This procedure is simple and useful for preparing gas-derivative crystals.
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Affiliation(s)
- Nobuhiro Mizuno
- Structural Biology Group, Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), 1-1-1 Kouto, Sayo, Hyogo 6795198, Japan
| | - Masatomo Makino
- Structural Biology Group, Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), 1-1-1 Kouto, Sayo, Hyogo 6795198, Japan
| | - Takashi Kumasaka
- Structural Biology Group, Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), 1-1-1 Kouto, Sayo, Hyogo 6795198, Japan
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Pourfathi M, Kuzma NN, Kara H, Ghosh RK, Shaghaghi H, Kadlecek SJ, Rizi RR. Propagation of dynamic nuclear polarization across the xenon cluster boundaries: elucidation of the spin-diffusion bottleneck. J Magn Reson 2013; 235:71-76. [PMID: 23981341 PMCID: PMC3832897 DOI: 10.1016/j.jmr.2013.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 06/24/2013] [Accepted: 07/09/2013] [Indexed: 06/02/2023]
Abstract
Earlier Dynamic Nuclear Polarization (DNP) experiments with frozen xenon/1-propanol/trityl mixtures have demonstrated spontaneous formation of pure xenon clusters above 120 K, enabling spectrally-resolved real-time measurements of (129)Xe nuclear magnetization in the clusters and in the surrounding radical-rich matrix. A spin-diffusion bottleneck was postulated to explain the peculiar time evolution of (129)Xe signals in the clusters as well as the apparent discontinuity of (129)Xe polarization across the cluster boundaries. A self-contained ab initio model of nuclear spin diffusion in heterogeneous systems is developed here, incorporating the intrinsic T1 relaxation towards the temperature-dependent equilibrium polarization and the spin-diffusion coefficients based on the measured NMR line widths and the known atomic densities in each compartment. This simple model provides the physical basis for the observed spin-diffusion bottleneck and is in a good quantitative agreement with the earlier measurements. A simultaneous fit of the model to the time-dependent NMR data at two different DNP frequencies provides excellent estimates of the cluster size, the intrinsic sample temperature, and (129)Xe T1 constants. The model was also applied to the NMR data acquired during relaxation towards the thermal equilibrium after the microwaves were turned off, to estimate T1 relaxation time constants inside and outside the clusters. Fitting the model to the data during and after DNP provides consistent estimates of the cluster size.
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Affiliation(s)
- M Pourfathi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, United States.
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38
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Abstract
Fluorination can alter the electronic properties of graphene and activate sites for subsequent chemistry. Here, we show that graphene fluorination depends on several variables, including XeF2 exposure and the choice of substrate. After fluorination, fluorine content declines by 50-80% over several days before stabilizing. While highly fluorinated samples remain insulating, mildly fluorinated samples regain some conductivity over this period. Finally, this loss does not reduce reactivity with alkylamines, suggesting that only nonvolatile fluorine participates in these reactions.
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Affiliation(s)
- Rory Stine
- Nova Research , 1900 Elkins Street Suite 230, Alexandria, Virginia 22308, United States
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39
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Lilburn DM, Pavlovskaya GE, Meersmann T. Perspectives of hyperpolarized noble gas MRI beyond 3He. J Magn Reson 2013; 229:173-186. [PMID: 23290627 PMCID: PMC3611600 DOI: 10.1016/j.jmr.2012.11.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/12/2012] [Accepted: 11/15/2012] [Indexed: 05/29/2023]
Abstract
Nuclear Magnetic Resonance (NMR) studies with hyperpolarized (hp) noble gases are at an exciting interface between physics, chemistry, materials science and biomedical sciences. This paper intends to provide a brief overview and outlook of magnetic resonance imaging (MRI) with hp noble gases other than hp (3)He. A particular focus are the many intriguing experiments with (129)Xe, some of which have already matured to useful MRI protocols, while others display high potential for future MRI applications. Quite naturally for MRI applications the major usage so far has been for biomedical research but perspectives for engineering and materials science studies are also provided. In addition, the prospects for surface sensitive contrast with hp (83)Kr MRI is discussed.
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40
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Tu H, Xu Y. A post silicon-on-insulator compatible smart tube technology. Lab Chip 2013; 13:1027-1030. [PMID: 23370972 DOI: 10.1039/c2lc41281k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This paper reports a technology to fabricate micro-parylene tubes with integrated sensors. The unique advantage of this new technology is its ability to incorporate high-temperature solid-state materials. Standard CMOS and MEMS devices can be fabricated first on the silicon wafers and then the smart tubes are formed by taking advantage of XeF(2) isotropic silicon etching and conformal parylene coating.
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Affiliation(s)
- Hongen Tu
- Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI 48202, USA
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41
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Booker RD, Sum AK. Biophysical changes induced by xenon on phospholipid bilayers. Biochim Biophys Acta 2013; 1828:1347-56. [PMID: 23376329 DOI: 10.1016/j.bbamem.2013.01.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 12/28/2012] [Accepted: 01/22/2013] [Indexed: 12/20/2022]
Abstract
Structural and dynamic changes in cell membrane properties induced by xenon, a volatile anesthetic molecule, may affect the function of membrane-mediated proteins, providing a hypothesis for the mechanism of general anesthetic action. Here, we use molecular dynamics simulation and differential scanning calorimetry to examine the biophysical and thermodynamic effects of xenon on model lipid membranes. Our results indicate that xenon atoms preferentially localize in the hydrophobic core of the lipid bilayer, inducing substantial increases in the area per lipid and bilayer thickness. Xenon depresses the membrane gel-liquid crystalline phase transition temperature, increasing membrane fluidity and lipid head group spacing, while inducing net local ordering effects in a small region of the lipid carbon tails and modulating the bilayer lateral pressure profile. Our results are consistent with a role for nonspecific, lipid bilayer-mediated mechanisms in producing xenon's general anesthetic action.
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Affiliation(s)
- Ryan D Booker
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
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42
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Bilir V, Frohn HJ. C6F5XeY molecules (Y = F and Cl): new synthetic approaches. first structural proof of the organoxenon halide molecule C6F5XeF. Acta Chim Slov 2013; 60:505-512. [PMID: 24169704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
The arylxenonium salt [C6F5Xe][BF4] reacts with different sources of nucleophiles, Y (naked fluoride, [N(CH3)4]F, the silanes, (CH3)3SiCl and (C2H5)3SiH, and the cadmiumorganyl, Cd(C6F5)2), in coordinating solvents (C2H5CN, CH3CN, CD3CN). While the products C6F5XeF, C6F5XeCl, and (C6F5)2Xe are well defined molecules, in reactions with (C2H5)3SiH only decomposition products presumably derived from <C6F5XeH> and <C6F5XeC2H5> are found. Molecular parameters and intermolecular contacts in the single crystal X-ray structure of C6F5XeF are discussed.
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43
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Tamadon F, Seidel S, Seppelt K. Reactions of xenon with iridium- and Osmiumhexafluoride. Acta Chim Slov 2013; 60:491-494. [PMID: 24169702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
Xenon and Iridiumhexafluoride react at temperatures above room temperature forming XeF+IrF6-. In presence of SbF5 FXe+IrSbF11- is formed. Xenon and Osmiumhexafluoride form in solution a blue charge transfer complex that cannot be isolated as a solid.
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Matafonova GG, Batoev VB, Linden KG. Photocatalytic-based inactivation of E. coli by UV 282 nm XeBr Excilamp. J Environ Sci Health A Tox Hazard Subst Environ Eng 2013; 48:1670-1676. [PMID: 23947705 DOI: 10.1080/10934529.2013.815492] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The impact of suspended TiO2 particles on the efficiency of UV inactivation of E. coli by XeBr excilamp (282 nm) was assessed using direct and integrating sphere spectroscopy for absorbance measurements in the calculations of UV doses. Complete disinfection (no quantifiable E. coli colonies) was observed at 30 (0.25 g/L of TiO2) and 40 mJ/cm(2) (0.1 g/L of TiO2), whereas UV alone and the treatment in the presence of 0.5 g/L of TiO2 produced tailing in the dose-response curves. The optimum concentration of TiO2 was found to be 0.25 g/L, which correlates with the highest •OH exposure (CT value) and steady state concentration of •OH. This study demonstrates the importance of proper calculation of UV dose and inclusion of •OH exposure effects when reporting results from disinfection studies using technologies with multiple modes of inactivation such as with UV/TiO2.
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Affiliation(s)
- Galina G Matafonova
- Analytical Center, Baikal Institute of Nature Management, Siberian Branch of Russian Academy of Sciences, Ulan-Ude, Russia.
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45
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Guirgis GA, Klaassen JJ, Deodhar BS, Sawant DK, Panikar SS, Dukes HW, Wyatt JK, Durig JR. Structure and conformation studies from temperature dependent infrared spectra of xenon solutions and ab initio calculations of cyclobutylgermane. Spectrochim Acta A Mol Biomol Spectrosc 2012; 99:266-278. [PMID: 23085284 DOI: 10.1016/j.saa.2012.09.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/09/2012] [Accepted: 09/16/2012] [Indexed: 06/01/2023]
Abstract
The infrared spectra (3500-220 cm(-1)) of cyclobutylgermane, c-C(4)H(7)GeH(3) have been recorded of the gas. Also variable temperature (-65 to -100 °C) studies of the infrared spectra (3500-400 cm(-1)) of the sample dissolved in liquid xenon were recorded and both the equatorial and axial conformers were identified. The enthalpy difference has been determined from 10 band pairs 8 temperatures to give 112 ± 11 cm(-1) (1.34 ± 0.13 kJ mol(-1)) with the equatorial conformer the more stable form. The percentage of the axial conformer present at ambient temperature is estimated to be 37 ± 1%. From ab initio calculations conformational stabilities have been predicted from both MP2(full) and density functional theory calculations from a variety of basic sets. The r(0) structure parameters have been obtained for both conformers from the previously reported rotational constants from the three isotopologues. The determined heavy atom distances for the equatorial [axial] form are (Å) Ge-C(α)=1.952(3) [1.950(3)], [Formula: see text] , [Formula: see text] [1.551(3)] and angles in degrees (°) ∠GeC(α)C(β)=118.6(5) [113.4(5)], [Formula: see text] , ∠C(α)C(β)C(γ)=87.8(5) [88.8(5)], [Formula: see text] and a puckering angle of 29.1(5) [25.1(5)]. Data from ab initio calculations were used to predict vibrational harmonic force constants, fundamental wavenumbers, infrared intensities, Raman activities and depolarization ratios for both conformers. The results are compared to the corresponding properties of some related molecules.
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Affiliation(s)
- Gamil A Guirgis
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424, USA
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46
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Araujo-Andrade C, Giuliano BM, Gómez-Zavaglia A, Fausto R. Structure and UV-induced photochemistry of 2-furaldehyde dimethylhydrazone isolated in rare gas matrices. Spectrochim Acta A Mol Biomol Spectrosc 2012; 97:830-837. [PMID: 22902581 DOI: 10.1016/j.saa.2012.07.061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 07/11/2012] [Accepted: 07/13/2012] [Indexed: 06/01/2023]
Abstract
In this work, a combined matrix isolation FTIR and theoretical DFT(B3LYP)/6-311++G(d,p) study of 2-furaldehyde dimethylhydrazone (2FDH) was performed. According to calculations, two E and two Z conformers exist, the E forms having considerably lower energy than the Z forms. The absence of relevant sterical hindrance between the two substituents around the CN bond (dimethylamino and 2-furyl) in the E structures and an extended π-p electron delocalization in the hydrazone moiety determines the higher stability of these species relatively to the Z structures. In the lowest energy form (E-AG) the O-C-CN and CN-N-Lp (Lp=lone electron pair of amine nitrogen atom) dihedral angles are predicted by the calculations to be -177.2° and 93.7°, respectively. The weak (NC)-H⋯O hydrogen bond type interaction (H⋯O distance: 252.2 pm) in form E-AG, together with the absence in this form of the destabilizing interaction between the lone electron pairs of the oxygen and nitrogen atoms existing in E-SG, explains its lower energy in comparison with this latter form. Both E-AG and E-SG conformers could be trapped from room temperature gas phase in low temperature argon and xenon matrices. The high E-SG→E-AG energy barrier (>25 kJ mol(-1)) explains that, upon increasing the temperature of the matrices no conformational isomerization could be observed. After irradiation of 2FDH with UV-light at λ>328 and λ>234 nm, two different photochemistries were observed. Irradiation at lower energy (λ>328nm) induced the E-AG→E-SG isomerization. Further irradiation at higher energy (λ>234 nm) led to a quick consumption of 2FDH and production of furan and dimethylisocyanide.
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Affiliation(s)
- C Araujo-Andrade
- Unidad Académica de Física de la Universidad Autónoma de Zacatecas, Zacatecas, Mexico
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47
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Marques JMC, Pereira FB. A detailed investigation on the global minimum structures of mixed rare-gas clusters: Geometry, energetics, and site occupancy. J Comput Chem 2012; 34:505-17. [PMID: 23108580 DOI: 10.1002/jcc.23161] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 09/20/2012] [Accepted: 09/28/2012] [Indexed: 11/07/2022]
Affiliation(s)
- Jorge M C Marques
- Departamento de Química, Universidade de Coimbra, Coimbra 3004-535, Portugal.
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48
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Yasui K, Kato K. Bubble dynamics and sonoluminescence from helium or xenon in mercury and water. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 86:036320. [PMID: 23031026 DOI: 10.1103/physreve.86.036320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 09/03/2012] [Indexed: 05/11/2023]
Abstract
Numerical simulations of bubble pulsation and sonoluminescence (SL) have been performed for helium or xenon bubbles in mercury and water under the experimental conditions of Futakawa et al. [M. Futakawa, T. Naoe, and M. Kawai, in Nonlinear Acoustics-Fundamentals and Applications: 18th International Symposium on Nonlinear Acoustics (ISNA 18), AIP Conf. Proc. No. 1022, edited by B. O. Enflo, C. M. Hedberg, and L. Kari (AIP, New York, 2008), p. 197]. The results of the numerical simulations have revealed that the bubble expansion is much larger in water than in mercury mainly because the density of water is one order of magnitude smaller than that of mercury. The SL intensity is higher in water than that in mercury although the maximum bubble temperature is lower. This is caused by the much larger amount of vapor inside a bubble as the saturated vapor pressure of water is four orders of magnitude larger than that of mercury at room temperature. The SL intensity from xenon is much larger than that from helium due both to lower ionization potential and higher bubble temperature due to lower thermal conductivity. The instantaneous SL power may be as large as 200 W from xenon in water. The maximum temperature inside a xenon bubble in mercury may be as high as about 80 000 K. It is suggested that the maximum pressure in mercury due to shock waves emitted from bubbles increases as the SL intensity increases, although they are not simply correlated in water because the amount of water vapor trapped inside a bubble influences the SL intensity in a complex way.
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Affiliation(s)
- Kyuichi Yasui
- National Institute of Advanced Industrial Science and Technology, 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan.
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49
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Abstract
Krypton (Kr) and xenon (Xe) adsorption on two partially fluorinated metal-organic frameworks (FMOFCu and FMOFZn) with different cavity size and topologies are reported. FMOFCu shows an inversion in sorption selectivity toward Kr at temperatures below 0 °C while FMOFZn does not. The 1D microtubes packed along the (101) direction connected through small bottleneck windows in FMOFCu appear to be the reason for this peculiar behavior. The FMOFCu shows an estimated Kr/Xe selectivity of 36 at 0.1 bar and 203 K.
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Affiliation(s)
- Carlos A Fernandez
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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50
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Chaste J, Eichler A, Moser J, Ceballos G, Rurali R, Bachtold A. A nanomechanical mass sensor with yoctogram resolution. Nat Nanotechnol 2012; 7:301-4. [PMID: 22466856 DOI: 10.1038/nnano.2012.42] [Citation(s) in RCA: 293] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 02/29/2012] [Indexed: 05/22/2023]
Abstract
Nanomechanical resonators have been used to weigh cells, biomolecules and gas molecules, and to study basic phenomena in surface science, such as phase transitions and diffusion. These experiments all rely on the ability of nanomechanical mass sensors to resolve small masses. Here, we report mass sensing experiments with a resolution of 1.7 yg (1 yg = 10(-24) g), which corresponds to the mass of one proton. The resonator is a carbon nanotube of length ∼150 nm that vibrates at a frequency of almost 2 GHz. This unprecedented level of sensitivity allows us to detect adsorption events of naphthalene molecules (C(10)H(8)), and to measure the binding energy of a xenon atom on the nanotube surface. These ultrasensitive nanotube resonators could have applications in mass spectrometry, magnetometry and surface science.
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Affiliation(s)
- J Chaste
- Catalan Institute of Nanotechnology, CIN2(ICN-CSIC), Campus de la UAB, 08193 Bellaterra, Barcelona, Spain
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