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Friedman Y, Steiner JM, Livshitz S, Perez E, Nowik I, Felner I, Wille HC, Wortmann G, Efrati O, Finkelstein A, Petitgirard S, Chumakov AI, Bessas D. The validity of an experiment testing the influence of acceleration on time dilation using a rotating Mössbauer absorber and a Synchrotron Mössbauer Source. J Synchrotron Radiat 2019; 26:473-482. [PMID: 30855258 DOI: 10.1107/s1600577519000857] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 01/17/2019] [Indexed: 06/09/2023]
Abstract
Three experiments are reviewed, performed (in 2014-2016) at ID18 of ESRF to measure the influence of acceleration on time dilation by measuring the relative shift between the absorption lines of two states of the same rotating absorber with accelerations anti-parallel and parallel to the incident beam. Statistically significant data for rotation frequencies up to 510 Hz in both directions of rotation were collected. For each run with high rotation, a stable statistically significant `vibration-free' relative shift between the absorption lines of the two states was measured. This may indicate the influence of acceleration on time dilation. However, the measured relative shift was also affected by the use of a slit necessary to focus the beam to the axis of rotation to a focal spot of sub-micrometre size. The introduction of the slit broke the symmetry in the absorption lines due to the nuclear lighthouse effect and affected the measured relative shift, preventing to claim conclusively the influence of acceleration on time dilation. Assuming that this loss of symmetry is of first order, the zero value of the relative shift, corrected for this loss, falls always within the experimental error limits, as predicted by Einstein's clock hypothesis. The requirements and an indispensable plan for a conclusive experiment, once the improved technology becomes available, is presented. This will be useful to future experimentalists wishing to pursue this experiment or a related rotor experiment involving a Mössbauer absorber and a synchrotron Mössbauer source.
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Affiliation(s)
- Y Friedman
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - J M Steiner
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - S Livshitz
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - E Perez
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - I Nowik
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - I Felner
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - H C Wille
- Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg, Germany
| | - G Wortmann
- Department Physik, Universität Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany
| | - O Efrati
- Colibri Spindles Ltd, Industrial Park Lavon, Bikat Bet Hakerem, Israel
| | - A Finkelstein
- Colibri Spindles Ltd, Industrial Park Lavon, Bikat Bet Hakerem, Israel
| | - S Petitgirard
- Bayerisches Geo-Institut, Universitätsstrasse 30, 95447 Bayreuth, Germany
| | - A I Chumakov
- ESRF - The European Synchrotron, CS40220, 38043 Grenoble Cédex 9, France
| | - D Bessas
- ESRF - The European Synchrotron, CS40220, 38043 Grenoble Cédex 9, France
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Friedman Y, Nowik I, Felner I, Steiner JM, Yudkin E, Livshitz S, Wille HC, Wortmann G, Chumakov AI. Advances in testing the effect of acceleration on time dilation using a synchrotron Mössbauer source. J Synchrotron Radiat 2017; 24:661-666. [PMID: 28452758 DOI: 10.1107/s1600577517002405] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/12/2017] [Indexed: 06/07/2023]
Abstract
New results, additional techniques and know-how acquired, developed and employed in a recent HC-1898 experiment at the Nuclear Resonance Beamline ID18 of ESRF are presented, in the quest to explore the acceleration effect on time dilation. Using the specially modified Synchrotron Mössbauer Source and KB-optics together with a rotating single-line semicircular Mössbauer absorber on the rim of a specially designed rotating disk, the aim was to measure the relative spectral shift between the spectra of two states when the acceleration of the absorber is anti-parallel and parallel to the source. A control system was used for the first time and a method to quantify the effects of non-random vibrations on the spectral shift was developed. For several runs where the effect of these vibrations was negligible, a stable statistically significant non-zero relative shift was observed. This suggests the influence of acceleration on time.
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Affiliation(s)
- Y Friedman
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - I Nowik
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - I Felner
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - J M Steiner
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - E Yudkin
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - S Livshitz
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - H C Wille
- Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg, Germany
| | - G Wortmann
- Department Physik, Universität Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany
| | - A I Chumakov
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France
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Friedman Y, Yudkin E, Nowik I, Felner I, Wille HC, Röhlsberger R, Haber J, Wortmann G, Arogeti S, Friedman M, Brand Z, Levi N, Shafir I, Efrati O, Frumson T, Finkelstein A, Chumakov AI, Kantor I, Rüffer R. Synchrotron radiation Mössbauer spectra of a rotating absorber with implications for testing velocity and acceleration time dilation. J Synchrotron Radiat 2015; 22:723-728. [PMID: 25931089 DOI: 10.1107/s1600577515001411] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 01/22/2015] [Indexed: 06/04/2023]
Abstract
Many Mössbauer spectroscopy (MS) experiments have used a rotating absorber in order to measure the second-order transverse Doppler (TD) shift, and to test the validity of the Einstein time dilation theory. From these experiments, one may also test the clock hypothesis (CH) and the time dilation caused by acceleration. In such experiments the absorption curves must be obtained, since it cannot be assumed that there is no broadening of the curve during the rotation. For technical reasons, it is very complicated to keep the balance of a fast rotating disk if there are moving parts on it. Thus, the Mössbauer source on a transducer should be outside the disk. Friedman and Nowik have already predicted that the X-ray beam finite size dramatically affects the MS absorption line and causes its broadening. We provide here explicit formulas to evaluate this broadening for a synchrotron Mössbauer source (SMS) beam. The broadening is linearly proportional to the rotation frequency and to the SMS beam width at the rotation axis. In addition, it is shown that the TD shift and the MS line broadening are affected by an additional factor assigned as the alignment shift which is proportional to the frequency of rotation and to the distance between the X-ray beam center and the rotation axis. This new shift helps to align the disk's axis of rotation to the X-ray beam's center. To minimize the broadening, one must focus the X-ray on the axis of the rotating disk and/or to add a slit positioned at the center, to block the rays distant from the rotation axis of the disk. Our experiment, using the (57)Fe SMS, currently available at the Nuclear Resonance beamline (ID18) at the ESRF, with a rotating stainless steel foil, confirmed our predictions. With a slit installed at the rotation axis (reducing the effective beam width from 15.6 µm to 5.4 µm), one can measure a statistically meaningful absorption spectrum up to 300 Hz, while, without a slit, such spectra could be obtained up to 100 Hz only. Thus, both the broadening and the alignment shift are very significant and must be taken into consideration in any rotating absorber experiment. Here a method is offered to measure accurately the TD shift and to test the CH.
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Affiliation(s)
- Y Friedman
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - E Yudkin
- Jerusalem College of Technology, POB 16031, Jerusalem 91160, Israel
| | - I Nowik
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - I Felner
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - H-C Wille
- Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg, Germany
| | - R Röhlsberger
- Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg, Germany
| | - J Haber
- Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg, Germany
| | - G Wortmann
- Department Physik, Universität Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany
| | - S Arogeti
- Ben-Gurion University of the Negev, Ber Sheva, Israel
| | - M Friedman
- Ben-Gurion University of the Negev, Ber Sheva, Israel
| | - Z Brand
- Nuclear Research Center Negev, Ber Sheva, Israel
| | - N Levi
- Nuclear Research Center Negev, Ber Sheva, Israel
| | - I Shafir
- Nuclear Research Center Negev, Ber Sheva, Israel
| | - O Efrati
- Colibri Spindles Ltd, Industrial Park Lavon, Bdg 1, MP Bikat Bet Hakerem 2011800, Israel
| | - T Frumson
- Colibri Spindles Ltd, Industrial Park Lavon, Bdg 1, MP Bikat Bet Hakerem 2011800, Israel
| | - A Finkelstein
- Colibri Spindles Ltd, Industrial Park Lavon, Bdg 1, MP Bikat Bet Hakerem 2011800, Israel
| | - A I Chumakov
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France
| | - I Kantor
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France
| | - R Rüffer
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France
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Retuerto M, Li MR, Go Y, Ignatov A, Croft M, Ramanujachary K, Herber R, Nowik I, Hodges J, Dachraoui W, Hadermann J, Greenblatt M. Corrigendum to “High magnetic ordering temperature in the perovskites Sr4−La Fe3ReO12 (x=0.0, 1.0, 2.0)” [J. Solid State Chem. 194 (2012) 48–58]. J SOLID STATE CHEM 2013. [DOI: 10.1016/j.jssc.2012.09.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Retuerto M, Li MR, Go YB, Ignatov A, Croft M, Ramanujachary KV, Hadermann J, Hodges JP, Herber RH, Nowik I, Greenblatt M. Magnetic and Structural Studies of the Multifunctional Material SrFe0.75Mo0.25O3−δ. Inorg Chem 2012; 51:12273-80. [DOI: 10.1021/ic301550m] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Retuerto
- Department of Chemistry and
Chemical Biology, Rutgers, The State University of New Jersey, 610
Taylor Road, Piscataway, New Jersey, 08854, United States
| | - M.-R. Li
- Department of Chemistry and
Chemical Biology, Rutgers, The State University of New Jersey, 610
Taylor Road, Piscataway, New Jersey, 08854, United States
| | - Y. B. Go
- Department of Chemistry and
Chemical Biology, Rutgers, The State University of New Jersey, 610
Taylor Road, Piscataway, New Jersey, 08854, United States
| | - A. Ignatov
- Department of Physics and Astronomy,
Rutgers, The State University of New Jersey, 136 Frelinghuysen Road,
Piscataway, New Jersey, 08854, United States
| | - M. Croft
- Department of Physics and Astronomy,
Rutgers, The State University of New Jersey, 136 Frelinghuysen Road,
Piscataway, New Jersey, 08854, United States
| | - K. V. Ramanujachary
- Department of Chemistry and Physics,
Rowan University, 210 Mullica Hill Road, Glassboro, New Jersey, 08028,
United States
| | - J. Hadermann
- EMAT, University
of Antwerp,
Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - J. P. Hodges
- Instrument and Source Design
Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831,
United States
| | - R. H. Herber
- Racah Institute
of Physics, Hebrew
University, Jerusalem, 91904 Israel
| | - I. Nowik
- Racah Institute
of Physics, Hebrew
University, Jerusalem, 91904 Israel
| | - M. Greenblatt
- Department of Chemistry and
Chemical Biology, Rutgers, The State University of New Jersey, 610
Taylor Road, Piscataway, New Jersey, 08854, United States
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Nowik I, Felner I, Ren Z, Cao GH, Xu ZA. Coexistence of ferromagnetism and superconductivity: magnetization and Mössbauer studies of EuFe₂(As₁ - xPx)₂. J Phys Condens Matter 2011; 23:065701. [PMID: 21406932 DOI: 10.1088/0953-8984/23/6/065701] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Magnetization and (57)Fe and (151)Eu Mössbauer studies of EuFe(2)(As(1 - x)P(x))(2) (x = 0-1.0) at temperatures (5-300 K) have been performed. The magnetization studies show a decrease of the divalent Eu sublattice antiferromagnetic transition temperature from T(AFM) = 20 K for x = 0 to 16 K at x≈0.2. For x > 0.2, the Eu sublattice is ferromagnetically ordered at T(FM), which increases up to 27 K for x = 1.0. For 0.2 < x < 0.5, the system becomes superconducting. (151)Eu Mössbauer studies in the antiferromagnetic range show a constant saturation hyperfine field of 26.2 T and that the magnetization is almost perpendicular to the c-axis. On the other hand, in the ferromagnetic range, the hyperfine field increases up to 30.8 T (for x = 1) and the easy axis is almost parallel to the c-axis. In both regions the magnetic axis seems to be tilted from the basal plane or the c-axis by ∼ 20°. The (57)Fe Mössbauer studies show no magnetism in the iron site for x > 0.2, yet at 5 K exhibit transferred magnetic hyperfine fields (∼1 T) from the ferromagnetically ordered Eu sublattice, even in the superconducting region. Superconductivity in the presence of ferromagnetism is generally not observable. However, transferred magnetic hyperfine fields in the superconducting state are observed here for the first time.
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Affiliation(s)
- I Nowik
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
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Sivakumar M, Gedanken A, Zhong W, Jiang YH, Du YW, Brukental I, Bhattacharya D, Yeshurun Y, Nowik I. Sonochemical synthesis of nanocrystalline LaFeO3. ACTA ACUST UNITED AC 2004. [DOI: 10.1039/b310110j] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Perkas N, Palchik O, Brukental I, Nowik I, Gofer Y, Y.Koltypin, and, A.Gedanken*. A Mesoporous Iron−Titanium Oxide Composite Prepared Sonochemically. J Phys Chem B 2003. [DOI: 10.1021/jp022447v] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Perkas
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel, Department of Physics, Bar-Ilan University, Ramat-Gan, 52900, Israel, and Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - O. Palchik
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel, Department of Physics, Bar-Ilan University, Ramat-Gan, 52900, Israel, and Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - I. Brukental
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel, Department of Physics, Bar-Ilan University, Ramat-Gan, 52900, Israel, and Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - I. Nowik
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel, Department of Physics, Bar-Ilan University, Ramat-Gan, 52900, Israel, and Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - Y. Gofer
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel, Department of Physics, Bar-Ilan University, Ramat-Gan, 52900, Israel, and Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - Y.Koltypin, and
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel, Department of Physics, Bar-Ilan University, Ramat-Gan, 52900, Israel, and Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - A.Gedanken*
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel, Department of Physics, Bar-Ilan University, Ramat-Gan, 52900, Israel, and Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
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Bauminger ER, Treffry A, Quail MA, Zhao Z, Nowik I, Harrison PM. Stages in iron storage in the ferritin of Escherichia coli (EcFtnA): analysis of Mössbauer spectra reveals a new intermediate. Biochemistry 1999; 38:7791-802. [PMID: 10387019 DOI: 10.1021/bi990377l] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron uptake into the nonheme ferritin of Escherichia coli (EcFtnA) and its site-directed variants have been investigated by Mössbauer spectroscopy. EcFtnA, like recombinant human H chain ferritin (HuHF), oxidized Fe(II) at a dinuclear ferroxidase center situated at a central position within each subunit. As with HuHF, Mössbauer subspectra observed between 1 min and 24 h after Fe(II) addition were assigned to Fe(III) monomers, "c", mu-oxo-bridged dimers, "b", and clusters, "a", the latter showing magnetically split spectra, "d", at 4.1 K. Like those of HuHF, the mu-oxo-bridged dimers were formed at the ferroxidase centers. However, the analysis also revealed the presence of a new type of dimer, "e" (QS1 = 0.38 mm/s, IS1 = 0.51 mm/s and QS2 = 0.72 mm/s, IS2 = 0.50 mm/s), and this was also assigned to the ferroxidase center. Dimers "b" appeared to be converted to dimers "e" over time. Subspectra "e" became markedly asymmetric at temperatures above 90 K, suggesting that the two Fe(III) atoms of dimers "e" were more weakly coupled than in the mu-oxo-bridged dimers "b", possibly due to OH- bridging. Monomeric Fe(III), giving relaxation spectra "c", was assigned to a unique site C that is near the dinuclear center. In EcFtnA all three iron atoms seemed to be oxidized together. In contrast to HuHF, no Fe(III) clusters were observed 24 h after the aerobic addition of 48 Fe(II) atoms/molecule in wild-type EcFtnA. This implies that iron is more evenly distributed between molecules in the bacterial ferritins, which may account for its greater accessibility.
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Affiliation(s)
- E R Bauminger
- Racah Institute of Physics, The Hebrew University, Jerusalem, Israel.
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Gałazka-Friedman J, Bauminger ER, Friedman A, Barcikowska M, Hechel D, Nowik I. Iron in parkinsonian and control substantia nigra--a Mössbauer spectroscopy study. Mov Disord 1996; 11:8-16. [PMID: 8771061 DOI: 10.1002/mds.870110104] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We used Mössbauer spectroscopy to study the iron content, the redox state, and the binding site of iron in substantia nigra (SN) from parkinsonian (PD) and control brains. Measurements performed on fresh-frozen, formalin-fixed, and lyophilized samples demonstrated the presence of ferric (Fe3+) iron only, both in PD and control SN. Ferrous iron, if present at all, may represent at most 5% of the total iron. We found no difference in the total amount of iron in SN between PD and control brains. The Mössbauer spectra observed at 4.1 K in fresh (frozen or lyophilized) samples were different from those obtained in formalin-fixed (frozen or lyophilized) samples. In the fresh samples, only ferritin-like iron was observed, whereas in the samples frozen or lyophilized from formalin, non-ferritin iron was detected.
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Friedman A, Bauminger ER, Gałazka-Friedman J, Barcikowska M, Hechel D, Nowik I, Marczewska M. Is iron involved in pathogenesis of Parkinson's disease--Mössbauer spectroscopy study of substantia nigra in control and disease brains. Neurol Neurochir Pol 1996; 30 Suppl 2:95-103. [PMID: 9100247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- A Friedman
- Department of Neurology, Warsaw Medical Academy
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Felner I, Asaf U, Nowik I, Bauminger ER, Goren SD, Korn C, Lütgemeier H, Schmenn S, Schone H. Magnetic order induced by hydrogen in superconducting RBa2Cu4O8 (R=Y,Gd) studied by Mössbauer and NQR techniques. Phys Rev B Condens Matter 1994; 50:15858-15863. [PMID: 9975954 DOI: 10.1103/physrevb.50.15858] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bauminger ER, Barcikowska M, Friedman A, Galazka-Friedman J, Hechel D, Nowik I. Does iron play a role in Parkinson's disease? ACTA ACUST UNITED AC 1994. [DOI: 10.1007/bf02064618] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bauminger ER, Treffry A, Hudson AJ, Hechel D, Hodson NW, Andrews SC, Levi S, Nowik I, Arosio P, Guest JR. Iron incorporation into ferritins: evidence for the transfer of monomeric Fe(III) between ferritin molecules and for the formation of an unusual mineral in the ferritin of Escherichia coli. Biochem J 1994; 302 ( Pt 3):813-20. [PMID: 7945207 PMCID: PMC1137303 DOI: 10.1042/bj3020813] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Iron that has been oxidized by H-chain ferritin can be transferred into other ferritin molecules before it is incorporated into mature ferrihydrite iron cores. Iron(III) dimers are formed at the ferroxidase centres of ferritin H chains at an early stage of Fe(II) oxidation. Mössbauer spectroscopic data now show that the iron is transferred as monomeric species arising from dimer dissociation and that it binds to the iron core of the acceptor ferritin. Human H-chain ferritin variants containing altered threefold channels can act as acceptors, as can the ferritin of Escherichia coli (Ec-FTN). A human H-chain ferritin variant with a substituted tyrosine (rHuHF-Y34F) can act as a donor of Fe(III). Since an Fe(III)-tyrosinate (first identified in bullfrog H-chain ferritin) is absent from variant rHuHF-Y34F, the Fe(III) transferred is not derived from this tyrosinate complex. Mössbauer parameters of the small iron cores formed within Ec-FTN are significantly different from those of mammalian ferritins. Analysis of the spectra suggests that they are derived from both ferrihydrite and non-ferrihydrite components. This provides further evidence that the ferritin protein shell can influence the structure of its iron core.
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Affiliation(s)
- E R Bauminger
- Racah Institute of Physics, Hebrew University, Jerusalem, Israel
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Wynter CI, Evans BJ, Thompson GK, Oliver FR, Spijkerman JJ, Stadelmaier ΗH, Lacey RA, Nowik I. Short Communication. Resolution of Ambiguous Magnetic Susceptibility Data by Means of Mössbauer Spectroscopy. RADIOCHIM ACTA 1994. [DOI: 10.1524/ract.1994.65.2.149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- C. I. Wynter
- Chemistry Department, Nassau Community College, Garden City, NY 11530
| | - B. J. Evans
- Chemistry Department, Michigan University, Ann Arbor, MI 48109-1055
| | - G. K. Thompson
- Chemistry Department, Michigan University, Ann Arbor, MI 48109-1055
| | - F. R. Oliver
- Physics Department, Morgan State University, Baltimore, MD 21239
| | | | - Η. H. Stadelmaier
- Department of Materials Science and Engineering, North Carolina State University, P.O. Box 7916, Raleigh, NC 27695-7916
| | - R. A. Lacey
- Chemistry Department, Stony Brook University, Stony Brook, NY 11790
| | - I. Nowik
- Racah Institute of Physics, The Hebrew University, Jerusalem, IL-91904, Israel
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Harrison PM, Bauminger ER, Hechel D, Hodson NW, Nowik I, Treffry A, Yewdall SJ. Mechanism of Fe(II) oxidation and core formation in ferritin. Adv Exp Med Biol 1994; 356:1-12. [PMID: 7887213 DOI: 10.1007/978-1-4615-2554-7_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- P M Harrison
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, U.K
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Bauminger ER, Harrison PM, Hechel D, Hodson NW, Nowik I, Treffry A, Yewdall SJ. Iron (II) oxidation and early intermediates of iron-core formation in recombinant human H-chain ferritin. Biochem J 1993; 296 ( Pt 3):709-19. [PMID: 8280069 PMCID: PMC1137754 DOI: 10.1042/bj2960709] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The paper describes a study of Fe(II) oxidation and the formation of Fe(III)-apoferritin complexes in recombinant human H-chain ferritin and its variants. The effects of site-directed changes in the conserved residues associated with a proposed ferroxidase centre have been investigated. A change in any of these residues is shown to reduce the rate of Fe(II) oxidation, confirming the importance of the ferroxidase centre in the catalysis of Fe(II) oxidation. Mössbauer and u.v.-difference spectroscopy show that in the wild-type protein Fe(II) oxidation gives rise to Fe(III) monomers, dimers and larger clusters. The formation of Fe(III) mu-oxo-bridged dimers occurs at the ferroxidase centre and is associated with fast oxidation: in three variants in which Fe(II) oxidation is especially slow, no Fe(III) dimers are seen. Within the time scale 0.5-20 min in wild-type human H-chain ferritin, dimer formation precedes that of the monomer and the progression dimer-->monomer-->cluster is observed, although not to completion. In a preliminary investigation of oxidation intermediates using a stopped-flow instrument, an Fe(III)-tyrosine complex reported by Waldo et al. (1993), is attributed to Tyr-34, a residue at the ferroxidase centre. The Fe(III)-Tyr-34 complex, forms in 0.5 s and then decays, as dimer absorbance increases. The relationship between Fe(III)-tyrosinate and the formation of Fe(III) dimers is uncertain.
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Affiliation(s)
- E R Bauminger
- Racah Institute of Physics, Hebrew University of Jerusalem, Israel
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Treffry A, Bauminger ER, Hechel D, Hodson NW, Nowik I, Yewdall SJ, Harrison PM. Defining the roles of the threefold channels in iron uptake, iron oxidation and iron-core formation in ferritin: a study aided by site-directed mutagenesis. Biochem J 1993; 296 ( Pt 3):721-8. [PMID: 7506527 PMCID: PMC1137755 DOI: 10.1042/bj2960721] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This paper aims to define the role of the threefold intersubunit channels in iron uptake and sequestration processes in the iron-storage protein, ferritin. Iron uptake, measured as loss of availability of Fe(II) to ferrozine (due to oxidation), has been studied in recombinant human H-chain ferritins bearing amino acid substitutions in the threefold channels or ferroxidase centres. Similar measurements with recombinant horse L-chain ferritin are compared. It is concluded that significant Fe(II) oxidation occurs only at the H-chain ferroxidase centres and not in the threefold channels, although this route is used by Fe(II) for entry. Investigations by Mössbauer and u.v.-difference spectroscopy show that part of the iron oxidized by H-chain ferritin returns to the threefold channels as Fe(III). This monomeric Fe(III) can be displaced by addition of Tb(III). Fe(III) also moves into the cavity for formation of the iron-core mineral, ferrihydrite. Iron incorporated into ferrihydrite becomes kinetically inert.
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Affiliation(s)
- A Treffry
- Racah Institute of Physics, Hebrew University of Jerusalem, Israel
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Felner I, Nowik I, Yaron U, Cohen O, Bauminger ER, Kroener T, Czjzek G. Magnetic properties, Mössbauer, and specific-heat studies of RBa2Fe3O8 (R=Y,Eu) compounds. Phys Rev B Condens Matter 1993; 48:16040-16046. [PMID: 10008164 DOI: 10.1103/physrevb.48.16040] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Felner I, Hechel D, Nowik I. Oxygen dependence of the antiferromagnetic order in La8-xSrxCu8Oy. Phys Rev B Condens Matter 1993; 47:5367-5372. [PMID: 10006703 DOI: 10.1103/physrevb.47.5367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Nowik I, Jacob I, Moreh R. Mössbauer study of crystallographic and magnetic phase transitions, phonon softening, and hyperfine interactions in Zr(AlxFe1-x)2. Phys Rev B Condens Matter 1993; 47:723-726. [PMID: 10005546 DOI: 10.1103/physrevb.47.723] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Nowik I, Felner I, Bauminger ER. Magnetic order and superconductivity in Bi2Sr2Ca1-xYxCu2O8. Phys Rev B Condens Matter 1992; 45:4912-4915. [PMID: 10002131 DOI: 10.1103/physrevb.45.4912] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Jacob I, Nowik I, Moreh R. A Mössbauer Evaluation of the 57Fe Debye Temperatures in the Zr(Al xFe 1− x) 2System*. Z PHYS CHEM 1992. [DOI: 10.1524/zpch.1992.1.1.595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Bauminger ER, Harrison PM, Hechel D, Nowik I, Treffry A. Mössbauer spectroscopic investigation of structure-function relations in ferritins. Biochim Biophys Acta 1991; 1118:48-58. [PMID: 1764477 DOI: 10.1016/0167-4838(91)90440-b] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ferritin plays an important role in iron metabolism and our aim is to understand the mechanisms by which iron is sequestered within its protein shell as the mineral ferrihydrite. We present Mössbauer spectroscopic data on recombinant human and horse spleen ferritin from which we draw the following conclusions: (1) that apoferritin catalyses Fe(II) oxidation as a first step in ferrihydrite deposition, (2) that the catalysis of Fe(II) oxidation is associated with residues situated within H chains, at the postulated 'ferroxidase centre' and not in the 3-fold inter-subunit channels previously suggested as the initial Fe(II) binding and oxidation site; (3) that both isolated Fe(III) and Fe(III) mu-oxo-bridged dimers found previously by Mössbauer spectroscopy to be intermediates in iron-core formation in horse spleen ferritin, are located on H chains; and (4) that these dimers form at ferroxidase centres. The importance of the ferroxidase centre is suggested by the conservation of its ligands in many ferritins from vertebrates, invertebrates and plants. Nevertheless iron-core formation does occur in those ferritins that lack ferroxidase centres even though the initial Fe(II) oxidation is relatively slow. We compare the early stages of core formation in such variants and in horse spleen ferritin in which only 10-15% of its chains are of the H type. We discuss our findings in relation to the physiological role of isoferritins in iron storage processes.
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Affiliation(s)
- E R Bauminger
- Racah Institute of Physics, Hebrew University, Jerusalem, Israel
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Artymiuk P, Bauminger E, Harrison P, Hechel D, Lawson D, Nowik I, Treffry A, Yewdall S. Understanding ferritin function with the help of Escherichia.coli: Mossbauer spectroscopic and structural studies of recombinant ferritins. J Inorg Biochem 1991. [DOI: 10.1016/0162-0134(91)84126-t] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
The iron-storage molecule ferritin can sequester up to 4500 Fe atoms as the mineral ferrihydrite. The iron-core is gradually built up when FeII is added to apoferritin and allowed to oxidize. Here we present evidence, from Mössbauer spectroscopic measurements, for the surprising result that iron atoms that are not incorporated into mature ferrihydrite particles, can be transferred between molecules. Experiments were done with both horse spleen ferritin and recombinant human ferritin. Mössbauer spectroscopy responds only to 57Fe and not to 56Fe and can distinguish chemically different species of iron. In our experiments a small number of 57FeII atoms were added to two equivalent apoferritin solutions and allowed to oxidize (1-5 min or 6 h). Either ferritin containing a small iron-core composed of 56Fe, or an equal volume of NaCl solution, was added and the mixture frozen in liquid nitrogen to stop the reaction at a chosen time. Spectra of the ferritin solution to which only NaCl was added showed a mixture of species including 57FeIII in solitary and dinuclear sites. In the samples to which 150 56FeIII-ferritin had been added the spectra showed that all, or almost all, of the 57FeIII was in large clusters. In these solutions 57FeIII initially present as intermediate species must have migrated to molecules containing large clusters. Such migration must now be taken into account in any model of ferritin iron-core formation.
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Affiliation(s)
- E R Bauminger
- Racah Institute of Physics, Hebrew University of Jerusalem, Israel
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Felner I, Nowik I, Brosh B, Hechel D, Bauminger ER. Superconductivity and magnetic order in the Cu(2) planes in Fe-doped YBa2Cu4O8. Phys Rev B Condens Matter 1991; 43:8737-8740. [PMID: 9996534 DOI: 10.1103/physrevb.43.8737] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Wortmann G, Nowik I, Perscheid B, Kaindl G, Felner I. Critical evaluation of Eu valences from LIII-edge x-ray-absorption and Mössbauer spectroscopy of EuNi2Si2-xGex. Phys Rev B Condens Matter 1991; 43:5261-5268. [PMID: 9997918 DOI: 10.1103/physrevb.43.5261] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Felner I, Nowik I, Bauminger ER, Hechel D, Yaron U. Competition between superconductivity and antiferromagnetism in Cu(2) layers of Y1-xPrxBa2Cu3-yMyOz, M=Fe,Co,Zn. Phys Rev Lett 1990; 65:1945-1948. [PMID: 10042404 DOI: 10.1103/physrevlett.65.1945] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Hechel D, Nowik I, Bauminger ER, Felner I. Magnetic order and superconductivity in YBa2Cu3-yMyOz (M=Fe,Co). Phys Rev B Condens Matter 1990; 42:2166-2173. [PMID: 9995661 DOI: 10.1103/physrevb.42.2166] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Felner I, Yaron U, Nowik I, Bauminger ER, Wolfus Y, Yacoby ER, Hilscher G, Pillmayr N. Magnetic order and superconductivity in Y1-xPrxBa2Cu3O7. Phys Rev B Condens Matter 1989; 40:6739-6744. [PMID: 9991047 DOI: 10.1103/physrevb.40.6739] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bauminger ER, Harrison PM, Nowik I, Treffry A. Mössbauer spectroscopic study of the initial stages of iron-core formation in horse spleen apoferritin: evidence for both isolated Fe(III) atoms and oxo-bridged Fe(III) dimers as early intermediates. Biochemistry 1989; 28:5486-93. [PMID: 2775718 DOI: 10.1021/bi00439a025] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Ferritin stores iron within a hollow protein shell as a polynuclear Fe(III) hydrous oxide core. Although iron uptake into ferritin has been studied previously, the early stages in the creation of the core need to be clarified. These are dealt with in this paper by using Mössbauer spectroscopy, a technique that enables several types of Fe(II) and Fe(III) to be distinguished. Systematic Mössbauer studies were performed on samples prepared by adding 57Fe(II) atoms to apoferritin as a function of pH (5.6-7.0), n [the number of Fe/molecule (4-480)], and tf (the time the samples were held at room temperature before freezing). The measurements made at 4.1 and 90 K showed that for samples with n less than or equal to 40 at pH greater than or equal to 6.25 all iron was trivalent at tf = 3 min. Four different Fe(III) species were identified: solitary Fe(III) atoms giving relaxation spectra, which can be identified with the species observed before by EPR and UV difference spectroscopy; oxo-bridged dimers giving doublet spectra with large splitting, observed for the first time in ferritin; small Fe(III) clusters giving doublets of smaller splitting and larger antiferromagnetically coupled Fe(III) clusters, similar to those found previously in larger ferritin iron cores, which, for samples with n greater than or equal to 40, gave magnetically split spectra at 4.1 K. Both solitary Fe(III) and dimers diminished with time, suggesting that they are intermediates in the formation of the iron core. Two kinds of divalent iron were distinguished for n = 480, which may correspond to bound and free Fe(II).
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Affiliation(s)
- E R Bauminger
- Racah Institute of Physics, Hebrew University, Jerusalem, Israel
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Nowik I, Kowitt M, Felner I, Bauminger ER. Magnetic order and superconductivity in RBa2Cu3Oz. Phys Rev B Condens Matter 1988; 38:6677-6682. [PMID: 9945344 DOI: 10.1103/physrevb.38.6677] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Yariv J, Kalb AJ, Helliwell JR, Papiz MZ, Bauminger ER, Nowik I. Chemical and Mössbauer spectroscopic evidence that iron-containing concanavalin A is a ferritin. J Biol Chem 1988; 263:13508-10. [PMID: 2458347] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We report here the preparation of iron-containing concanavalin A. It has a protein-to-iron ratio of 2.0, and the iron compound it contains is particulate with an average diameter of 85 A. Iron-containing concanavalin A interacts reversibly with dextran and with methyl alpha-D-glucoside. The molecular basis of these findings is discussed and a possible mechanism suggested where one of the molecular forms of concanavalin A has the structure of an apoferritin into which iron is deposited in the form of ferrihydrite.
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Affiliation(s)
- J Yariv
- Department of Biophysics, Weizmann Institute of Science, Rehovot, Israel
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Nowik I, Felner I, Voiron J, Beille J, Najib A, Gratz G. Pressure, substitution, and magnetic-field dependence of the valence phase transition in Yb0.4In. Phys Rev B Condens Matter 1988; 37:5633-5638. [PMID: 9943758 DOI: 10.1103/physrevb.37.5633] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Felner I, Nowik I, Yeshurun Y. Effects of substitution of O by S and Cu by Fe on superconductivity in YBa2Cu. Phys Rev B Condens Matter 1987; 36:3923-3925. [PMID: 9943339 DOI: 10.1103/physrevb.36.3923] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Felner I, Nowik I, Vaknin D, Potzel U, Moser J, Kalvius GM, Wortmann G, Schmiester G, Hilscher G, Gratz E, Schmitzer C, Pillmayr N, Prasad KG, Pinto H. Ytterbium valence phase transition in YbxIn1-xCu2. Phys Rev B Condens Matter 1987; 35:6956-6963. [PMID: 9940955 DOI: 10.1103/physrevb.35.6956] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Nowik I, Bauminger ER, Cohen SG, Ofer S. Spectral shapes of Mössbauer absorption and incoherent neutron scattering from harmonically bound nuclei in Brownian motion: Applications to macromolecular systems. Phys Rev A Gen Phys 1985; 31:2291-2299. [PMID: 9895761 DOI: 10.1103/physreva.31.2291] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Abstract
Diffusive motions of the magnetosomes (enveloped Fe3O4 particles) in the magnetotactic bacterium Aquaspirillum magnetotacticum result in a very broad-line Mössbauer spectrum (T approximately 100 mm/s) above freezing temperatures. The line width increases with increasing temperature. The data are analyzed using a bounded diffusion model to yield the rotational and translational motions of the magnetosomes as well as the effective viscosity of the material surrounding the magnetosomes. The results are [theta 2] l/2 less than 1.5 degrees and [x2] 1/2 less than 8.4 A for the rotational and translational motions, respectively, implying that the particles are fixed in whole cells. The effective viscosity is 10 cP at 295 K and increases with decreasing temperature. Additional Fe3+ material in the cell is shown to be associated with the magnetosomes. Fe2+ material in the cell appears to be associated with the cell envelope.
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Bauminger ER, Cohen SG, Nowik I, Ofer S, Yariv J. Evidence for temperature dependent anisotropic diffusive motion of heme iron in crystals of myoglobin through Mossbauer spectroscopy. ACTA ACUST UNITED AC 1983. [DOI: 10.1007/bf02147385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bauminger ER, Cohen SG, Nowik I, Ofer S, Yariv J. Dynamics of heme iron in crystals of metmyoglobin and deoxymyoglobin. Proc Natl Acad Sci U S A 1983; 80:736-40. [PMID: 6572364 PMCID: PMC393454 DOI: 10.1073/pnas.80.3.736] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The 57Fe gamma-ray resonance absorption spectra have been measured in crystals of metmyoglobin and deoxymyoglobin over a wide range of temperatures. Above a critical temperature common to both proteins (220 K), the dynamics of heme iron display a dramatic change, in that two kinds of thermal fluctuations come into play--a fast fluctuation associated with a steep decrease of the total fluctuation of characteristic time 10(-8) sec, associated with bounded diffusive motion. By using both discrete jump and continuous diffusion models, the latter based on the Brownian motion of an overdamped harmonic oscillator, the essential parameters of the iron motion (mean square displacement and jump frequency or diffusion constant) can be derived as a function of temperature. Thus, for deoxy Mb at 288 K, the mean square displacement for the fast fluctuation is about 6 X 10(-2) A2 and for the diffusive motion is 1.6 X 10(-2) A2; the diffusion constant is 4 X 10(-10) cm2/sec. The diffusive process is associated with an activation energy of about 0.75 kcal/mol. Although the same general kinds of phenomena are observed in crystals of MetMb and deoxy Mb, significant differences in behavior are found, which suggest that the main dynamical phenomenon observed reflects internal large-scale motions of the protein.
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Atzmony U, Bauminger ER, Nowik I, Ofer S, Wernick JH. Isomer Shifts and Mössbauer-Effect Efficiencies in Intermetallic Compounds of Europium. ACTA ACUST UNITED AC 1967. [DOI: 10.1103/physrev.156.262] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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