Magnetic resonance (Gottingen, Germany)最新文献

{"title":"Fluorine NMR study of proline-rich sequences using fluoroprolines.","authors":"Davy Sinnaeve, Abir Ben Bouzayene, Emile Ottoy, Gert-Jan Hofman, Eva Erdmann, Bruno Linclau, Ilya Kuprov, José C Martins, Vladimir Torbeev, Bruno Kieffer","doi":"10.5194/mr-2-795-2021","DOIUrl":"10.5194/mr-2-795-2021","url":null,"abstract":"<p><p>Proline homopolymer motifs are found in many proteins; their peculiar conformational and dynamic properties are often directly involved in those proteins' functions. However, the dynamics of proline homopolymers is hard to study by NMR due to a lack of amide protons and small chemical shift dispersion. Exploiting the spectroscopic properties of fluorinated prolines opens interesting perspectives to address these issues. Fluorinated prolines are already widely used in protein structure engineering - they introduce conformational and dynamical biases - but their use as <math><msup><mi></mi><mn>19</mn></msup></math>F NMR reporters of proline conformation has not yet been explored. In this work, we look at model peptides where C<math><mi>γ</mi></math>-fluorinated prolines with opposite configurations of the chiral C<math><mi>γ</mi></math> centre have been introduced at two positions in distinct polyproline segments. By looking at the effects of swapping these (4<math><mi>R</mi></math>)-fluoroproline and (4<math><mi>S</mi></math>)-fluoroproline within the polyproline segments, we were able to separate the intrinsic conformational properties of the polyproline sequence from the conformational alterations instilled by fluorination. We assess the fluoroproline <math><msup><mi></mi><mn>19</mn></msup></math>F relaxation properties, and we exploit the latter in elucidating binding kinetics to the SH3 (Src homology 3) domain.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":"2 2","pages":"795-813"},"PeriodicalIF":0.0,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10539733/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71415918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of conformational exchange processes using methyl-TROSY-based Hahn echo measurements of quadruple-quantum relaxation.","authors":"Christopher A Waudby, John Christodoulou","doi":"10.5194/mr-2-777-2021","DOIUrl":"10.5194/mr-2-777-2021","url":null,"abstract":"<p><p>Transverse nuclear spin relaxation is a sensitive probe of chemical exchange on timescales on the order of microseconds to milliseconds. Here we present an experiment for the simultaneous measurement of the relaxation rates of two quadruple-quantum transitions in <math><msup><mi></mi><mn>13</mn></msup></math>CH<math><msub><mi></mi><mn>3</mn></msub></math>-labelled methyl groups. These coherences are protected against relaxation by intra-methyl dipolar interactions and so have unexpectedly long lifetimes within perdeuterated biomacromolecules. However, these coherences also have an order of magnitude higher sensitivity to chemical exchange broadening than lower order coherences and therefore provide ideal probes of dynamic processes. We show that analysis of the static magnetic field dependence of zero-, double- and quadruple-quantum Hahn echo relaxation rates provides a robust indication of chemical exchange and can determine the signed relative magnitudes of proton and carbon chemical shift differences between ground and excited states. We also demonstrate that this analysis can be combined with established Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion measurements, providing improved precision in parameter estimates, particularly in the determination of <math><msup><mi></mi><mn>1</mn></msup></math>H chemical shift differences.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":"2 2","pages":"777-793"},"PeriodicalIF":0.0,"publicationDate":"2021-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10583286/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71415916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insight into the structure of black coatings of ancient Egyptian mummies by advanced Electron magnetic resonance of vanadyl complexes","authors":"Charles-Emmanuel Dutoit, L. Binet, H. Vezin, Océane Anduze, A. Lattuati-Derieux, D. Gourier","doi":"10.21203/rs.3.rs-1023443/v1","DOIUrl":"https://doi.org/10.21203/rs.3.rs-1023443/v1","url":null,"abstract":"\u0000 Advanced EPR techniques such as ENDOR and pulsed EPR are used to investigate the enigmatic black coatings of ancient Egyptian mummies, consisting in a complex and heterogeneous mixtures of conifer resins, wax, fat and oil with variable amounts of bitumen. Natural bitumen always contains traces of vanadyl porphyrin complexes that we used here as internal probes to explore the nanoscale environment of V4+ ions in these black coatings by hyperfine spectroscopy. Four types of vanadyl porphyrins were identified from the analysis of 14N hyperfine interactions. Three types (referred to as VO-P1, VO-P2 and VO-P3) are present in natural bitumen from the Dead Sea, among which VO-P1 and VO-P2 are also present in black coatings of mummies. The absence of VO-P3 in mummies, which is replaced by another complex VO-P4, may be due to its transformation during preparation of the black matter for embalming. Analysis of 1H hyperfine interaction shows that bitumen and other natural substances are intimately mixed in these black coatings, with bitumen aggregate sizes not larger than a few nanometres.","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41965183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anomalous amide proton chemical shifts as signatures of hydrogen bonding to aromatic sidechains.","authors":"Kumaran Baskaran, Colin W Wilburn, Jonathan R Wedell, Leonardus M I Koharudin, Eldon L Ulrich, Adam D Schuyler, Hamid R Eghbalnia, Angela M Gronenborn, Jeffrey C Hoch","doi":"10.5194/mr-2-765-2021","DOIUrl":"10.5194/mr-2-765-2021","url":null,"abstract":"<p><p>Hydrogen bonding between an amide group and the p-<math><mi>π</mi></math> cloud of an aromatic ring was first identified in a protein in the 1980s. Subsequent surveys of high-resolution X-ray crystal structures found multiple instances, but their preponderance was determined to be infrequent. Hydrogen atoms participating in a hydrogen bond to the p-<math><mi>π</mi></math> cloud of an aromatic ring are expected to experience an upfield chemical shift arising from a shielding ring current shift. We surveyed the Biological Magnetic Resonance Data Bank for amide hydrogens exhibiting unusual shifts as well as corroborating nuclear Overhauser effects between the amide protons and ring protons. We found evidence that Trp residues are more likely to be involved in p-<math><mi>π</mi></math> hydrogen bonds than other aromatic amino acids, whereas His residues are more likely to be involved in in-plane hydrogen bonds, with a ring nitrogen acting as the hydrogen acceptor. The p-<math><mi>π</mi></math> hydrogen bonds may be more abundant than previously believed. The inclusion in NMR structure refinement protocols of shift effects in amide protons from aromatic sidechains, or explicit hydrogen bond restraints between amides and aromatic rings, could improve the local accuracy of sidechain orientations in solution NMR protein structures, but their impact on global accuracy is likely be limited.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":"2 2","pages":"765-775"},"PeriodicalIF":0.0,"publicationDate":"2021-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10539802/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71415917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The relation between crystal structure and the occurrence of quantum-rotor-induced polarization.","authors":"Corinna Dietrich, Julia Wissel, Oliver Lorenz, Arafat Hossain Khan, Marko Bertmer, Somayeh Khazaei, Daniel Sebastiani, Jörg Matysik","doi":"10.5194/mr-2-751-2021","DOIUrl":"10.5194/mr-2-751-2021","url":null,"abstract":"<p><p>Among hyperpolarization techniques, quantum-rotor-induced polarization (QRIP), also known as the Haupt effect, is a peculiar one. It is, on the one hand, rather simple to apply by cooling and heating a sample. On the other hand, only the methyl groups of a few substances seem to allow for the effect, which strongly limits the applicability of QRIP. While it is known that a high tunnel frequency is required, the structural conditions for the effect to occur have not been exhaustively studied yet. Here we report on our efforts to heuristically recognize structural motifs in molecular crystals able to allow to produce QRIP.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":" ","pages":"751-763"},"PeriodicalIF":0.0,"publicationDate":"2021-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10539751/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44968591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms of coherent re-arrangement for long-lived spin order.","authors":"Florin Teleanu,&nbsp;Paul R Vasos","doi":"10.5194/mr-2-741-2021","DOIUrl":"10.5194/mr-2-741-2021","url":null,"abstract":"<p><p>Long-lived spin order-based approaches for magnetic resonance rely on the transition between two magnetic environments of different symmetries, one governed by the magnetic field of the spectrometer and the other where this strong magnetic field is inconsequential. Research on the excitation of magnetic-symmetry transitions in nuclear spins is a scientific field that debuted in Southampton in the year 2000. We advanced in this field carrying the baggage of pre-established directions in NMR spectroscopy. We propose to reveal herein the part of discoveries that may have been obscured by our choice to only look at them through the experience of such pre-established directions at the time. The methodological developments that are emphasised herein are the mechanisms of translation between the symmetric and non-symmetric environments with respect to the main magnetic field <math><mrow><msub><mi>B</mi><mn>0</mn></msub></mrow></math>. More specifically, we look again thoroughly at zero-quantum rotations in the starting blocks of long-lived state populations, magnetisation transfers between hyperpolarised heteronuclei, and protons. These pulse sequences seed subsequent magnetic mechanisms that contribute to further applications. For instance, we show how some of the introduced coherence rotations were combined with classical pulse blocks to obtain two-dimensional correlations between protons and heteronuclei. We hope the pulse sequence building blocks discussed herein will open further perspectives for magnetic resonance experiments with long-lived spin order.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":"2 2","pages":"741-749"},"PeriodicalIF":0.0,"publicationDate":"2021-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10539845/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71415919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supplementary material to \"Localising individual atoms of tryptophan side chains in the metallo-β-lactamase IMP-1 by pseudocontact shifts from paramagnetic lanthanoid tags at multiple sites\"","authors":"H. Orton, Iresha D Herath, A. Maleckis, Shereen Jabar, M. Szabó, B. Graham, Colum Breen, Lydia Topping, Stephen J. Butler, G. Otting","doi":"10.5194/mr-2021-63-supplement","DOIUrl":"https://doi.org/10.5194/mr-2021-63-supplement","url":null,"abstract":"Abstract. The metallo-β-lactamase IMP-1 features a flexible loop near the active site that assumes different conformations in single crystal structures, which may assist in substrate binding and enzymatic activity. To probe the position of this loop, we labelled the tryptophan residues of IMP-1 with 7-13C-indole and the protein with lanthanoid tags at three different sites. The magnetic susceptibility anisotropy (Δχ) tensors were determined by measuring pseudocontact shifts (PCS) of backbone amide protons. The Δχ tensors were subsequently used to identify the atomic coordinates of the tryptophan side chains in the protein. The PCSs were sufficient to determine the location of Trp28, which is located in the active site loop targeted by our experiments, with high accuracy. Its average atomic coordinates showed barely significant changes in response to the inhibitor captopril. It was found that localisation spaces could be defined with better accuracy by including only the PCSs of a single paramagnetic lanthanoid ion for each tag and tagging site. The effect was attributed to the shallow angle with which PCS isosurfaces tend to intersect if generated by tags and tagging sites that are identical except for the paramagnetic lanthanoid ion.\u0000","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48934164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Signal-to-noise ratio in diffusion-ordered spectroscopy: how good is good enough?","authors":"Jamie Guest,&nbsp;Peter Kiraly,&nbsp;Mathias Nilsson,&nbsp;Gareth A Morris","doi":"10.5194/mr-2-733-2021","DOIUrl":"10.5194/mr-2-733-2021","url":null,"abstract":"<p><p>Diffusion-ordered NMR spectroscopy (DOSY) constructs multidimensional spectra displaying signal strength as a function of Larmor frequency and of diffusion coefficient from experimental measurements using pulsed field gradient spin or stimulated echoes. Peak positions in the diffusion domain are determined by diffusion coefficients estimated by fitting experimental data to some variant of the Stejskal-Tanner equation, with the peak widths determined by the standard error estimated in the fitting process. The accuracy and reliability of the diffusion domain in DOSY spectra are therefore determined by the uncertainties in the experimental data and thus in part by the signal-to-noise ratio of the experimental spectra measured. Here the Cramér-Rao lower bound, Monte Carlo methods, and experimental data are used to investigate the relationship between signal-to-noise ratio, experimental parameters, and diffusion domain accuracy in 2D DOSY experiments. Experimental results confirm that sources of error other than noise put an upper limit on the improvement in diffusion domain accuracy obtainable by time averaging.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":"2 2","pages":"733-739"},"PeriodicalIF":0.0,"publicationDate":"2021-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10539768/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71415924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid assessment of Watson-Crick to Hoogsteen exchange in unlabeled DNA duplexes using high-power SELOPE imino ¹H CEST.","authors":"Bei Liu, Atul Rangadurai, Honglue Shi, Hashim M Al-Hashimi","doi":"10.5194/mr-2-715-2021","DOIUrl":"10.5194/mr-2-715-2021","url":null,"abstract":"<p><p>In duplex DNA, Watson-Crick A-T and G-C base pairs (bp's) exist in dynamic equilibrium with an alternative Hoogsteen conformation, which is low in abundance and short-lived. Measuring how the Hoogsteen dynamics varies across different DNA sequences, structural contexts and physiological conditions is key for identifying potential Hoogsteen hot spots and for understanding the potential roles of Hoogsteen base pairs in DNA recognition and repair. However, such studies are hampered by the need to prepare <math><msup><mi></mi><mn>13</mn></msup></math>C or <math><msup><mi></mi><mn>15</mn></msup></math>N isotopically enriched DNA samples for NMR relaxation dispersion (RD) experiments. Here, using SELective Optimized Proton Experiments (SELOPE) <math><msup><mi></mi><mn>1</mn></msup></math>H CEST experiments employing high-power radiofrequency fields (<math><mrow><msub><mi>B</mi><mn>1</mn></msub></mrow></math> <math><mo>></mo></math> 250 Hz) targeting imino protons, we demonstrate accurate and robust characterization of Watson-Crick to Hoogsteen exchange, without the need for isotopic enrichment of the DNA. For 13 residues in three DNA duplexes under different temperature and pH conditions, the exchange parameters deduced from high-power imino <math><msup><mi></mi><mn>1</mn></msup></math>H CEST were in very good agreement with counterparts measured using off-resonance <math><msup><mi></mi><mn>13</mn></msup></math>C <math><mo>/</mo></math> <math><msup><mi></mi><mn>15</mn></msup></math>N spin relaxation in the rotating frame (<math><mrow><msub><mi>R</mi><mrow><mn>1</mn><mi>ρ</mi></mrow></msub></mrow></math>). It is shown that <math><msup><mi></mi><mn>1</mn></msup></math>H-<math><msup><mi></mi><mn>1</mn></msup></math>H NOE effects which typically introduce artifacts in <math><msup><mi></mi><mn>1</mn></msup></math>H-based measurements of chemical exchange can be effectively suppressed by selective excitation, provided that the relaxation delay is short (<math><mo>≤</mo></math> 100 ms). The <math><msup><mi></mi><mn>1</mn></msup></math>H CEST experiment can be performed with <math><mo>∼</mo></math> 10<math><mo>×</mo></math> higher throughput and <math><mo>∼</mo></math> 100<math><mo>×</mo></math> lower cost relative to <math><msup><mi></mi><mn>13</mn></msup></math>C <math><mo>/</mo></math> <math><msup><mi></mi><mn>15</mn></msup></math>N <math><mrow><msub><mi>R</mi><mrow><mn>1</mn><mi>ρ</mi></mrow></msub></mrow></math> and enabled Hoogsteen chemical exchange measurements undetectable by <math><mrow><msub><mi>R</mi><mrow><mn>1</mn><mi>ρ</mi></mrow></msub></mrow></math>. The results reveal an increased propensity to form Hoogsteen bp's near terminal ends and a diminished propensity within A-tract motifs. The <math><msup><mi></mi><mn>1</mn></msup></math>H CEST experiment provides a basis for rapidly screening Hoogsteen breathing in duplex DNA, enabling identification of unusual motifs for more in-depth characterization.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":" ","pages":"715-731"},"PeriodicalIF":0.0,"publicationDate":"2021-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10539785/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47842256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the modeling of amplitude-sensitive electron spin resonance (ESR) detection using voltage-controlled oscillator (VCO)-based ESR-on-a-chip detectors.","authors":"Anh Chu,&nbsp;Benedikt Schlecker,&nbsp;Michal Kern,&nbsp;Justin L Goodsell,&nbsp;Alexander Angerhofer,&nbsp;Klaus Lips,&nbsp;Jens Anders","doi":"10.5194/mr-2-699-2021","DOIUrl":"10.5194/mr-2-699-2021","url":null,"abstract":"<p><p>In this paper, we present an in-depth analysis of a voltage-controlled oscillator (VCO)-based sensing method for electron spin resonance (ESR) spectroscopy, which greatly simplifies the experimental setup compared to conventional detection schemes. In contrast to our previous oscillator-based ESR detectors, where the ESR signal was encoded in the oscillation frequency, in the amplitude-sensitive method, the ESR signal is sensed as a change of the oscillation amplitude of the VCO. Therefore, using VCO architecture with a built-in amplitude demodulation scheme, the experimental setup reduces to a single permanent magnet in combination with a few inexpensive electronic components. We present a theoretical analysis of the achievable limit of detection, which uses perturbation-theory-based VCO modeling for the signal and applies a stochastic averaging approach to obtain a closed-form expression for the noise floor. Additionally, the paper also introduces a numerical model suitable for simulating oscillator-based ESR experiments in a conventional circuit simulator environment. This model can be used to optimize sensor performance early on in the design phase. Finally, all presented models are verified against measured results from a prototype VCO operating at 14 <math><mrow><mi>GHz</mi></mrow></math> inside a 0.5 <math><mrow><mi>T</mi></mrow></math> magnetic field.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":" ","pages":"699-713"},"PeriodicalIF":0.0,"publicationDate":"2021-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10539732/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46739464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}