{"title":"Nuclear-spin relaxation in paramagnetic solutions when the electronic zero-field splitting and zeeman interactions are of arbitrary magnitude","authors":"Robert R Sharp","doi":"10.1016/0022-2364(92)90056-D","DOIUrl":"10.1016/0022-2364(92)90056-D","url":null,"abstract":"<div><p>Expressions for the dipolar nuclear-spin relaxation rates in paramagnetic salt solutions have been derived under conditions where the electronic zero-field splitting (zfs) and Zeeman interactions are of arbitrary magnitude and when electron-spin relaxation is rapid compared to molecular reorientation. The theory is intended to provide continuity between the limiting analytical expressions previously derived for the Zeeman limit [Solomon-Bloembergen-Morgan (SBM) theory] and the zfs limit (R. Sharp, <em>J Chem. Phys.</em> <strong>93</strong>, 6921, 1990). The more general solutions parallel the forms of both of these limiting theories in that they are comprised of sums of terms, each term consisting of a mean-square dipolar coupling energy times a spectral density function at one of the transition frequencies of the coupled I-S spin system. Geometric aspects of the problem are exhibited in simplest form in terms of spherical tensors, and the resulting expressions reduce in a straightforward manner to the Zeeman- and zfs-limit equations. As in the limiting theories, the electronspin relaxation time is treated as a parameter of the theory rather than calculated in detail from the time dependence of the electron-spin Hamiltonian. The theory has been applied to the analysis of magnetic field-dependent proton relaxation data of the ligand methyl protons in solutions of tris(acetylacetonato)Mn(III). The agreement with experiment is much superior to that found for SBM theory.</p></div>","PeriodicalId":100800,"journal":{"name":"Journal of Magnetic Resonance (1969)","volume":"100 3","pages":"Pages 491-516"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-2364(92)90056-D","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74381564","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":"Temperature dependence of g values of Fe(I) and Ru (I) cyanide complexes in a KCl host lattice","authors":"C.D de Abreu, N.M Pinhal, N.V Vugman","doi":"10.1016/0022-2364(92)90064-E","DOIUrl":"10.1016/0022-2364(92)90064-E","url":null,"abstract":"","PeriodicalId":100800,"journal":{"name":"Journal of Magnetic Resonance (1969)","volume":"100 3","pages":"Pages 588-592"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-2364(92)90064-E","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88664192","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":"The equivalent of the DQF-COSY experiment, with one transient per t1 value, by use of B1 gradients","authors":"J Brondeau , D Boudot , P Mutzenhardt, D Canet","doi":"10.1016/0022-2364(92)90068-I","DOIUrl":"10.1016/0022-2364(92)90068-I","url":null,"abstract":"","PeriodicalId":100800,"journal":{"name":"Journal of Magnetic Resonance (1969)","volume":"100 3","pages":"Pages 611-618"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-2364(92)90068-I","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78127437","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":"Editor's note","authors":"","doi":"10.1016/0022-2364(92)90052-9","DOIUrl":"https://doi.org/10.1016/0022-2364(92)90052-9","url":null,"abstract":"","PeriodicalId":100800,"journal":{"name":"Journal of Magnetic Resonance (1969)","volume":"100 3","pages":"Page 451"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-2364(92)90052-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136496405","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}
Johan Kordel , Charlotta Johansson , Torbjorn Drakenberg
{"title":"113Cd NMR relaxation study of the protein calbindin D9K","authors":"Johan Kordel , Charlotta Johansson , Torbjorn Drakenberg","doi":"10.1016/0022-2364(92)90063-D","DOIUrl":"10.1016/0022-2364(92)90063-D","url":null,"abstract":"","PeriodicalId":100800,"journal":{"name":"Journal of Magnetic Resonance (1969)","volume":"100 3","pages":"Pages 581-587"},"PeriodicalIF":0.0,"publicationDate":"1992-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-2364(92)90063-D","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79371489","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":"NMR relaxation in adsorbed water","authors":"K Overloop, L van Gerven","doi":"10.1016/0022-2364(92)90263-7","DOIUrl":"https://doi.org/10.1016/0022-2364(92)90263-7","url":null,"abstract":"<div><p>The NMR relaxation behavior of the proton magnetization in adsorbed water is investigated. Longitudinal as well as transverse relaxation of the adsorbed water as a whole shows a distinct nonexponentiality and the nature of this nonexponentiality is studied. Different methods of fitting distribution of relaxation times are examined and various simulated and experimental decay curves are submitted to these fitting methods. The results of these fittings clearly indicate that both the longitudinal and the transverse relaxation of the proton magnetization in adsorbed water is related to two or three discrete components and that there is certainly no broad distribution of relaxation times present in these water-adsorbent systems.</p></div>","PeriodicalId":100800,"journal":{"name":"Journal of Magnetic Resonance (1969)","volume":"100 2","pages":"Pages 303-315"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-2364(92)90263-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90001356","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}
Joseph Augspurger , John G Pearson , Eric Oldfield , Clifford E Dykstra , Ki Deok Park , Dwight Schwartz
{"title":"Chemical-shift ranges in proteins","authors":"Joseph Augspurger , John G Pearson , Eric Oldfield , Clifford E Dykstra , Ki Deok Park , Dwight Schwartz","doi":"10.1016/0022-2364(92)90267-B","DOIUrl":"https://doi.org/10.1016/0022-2364(92)90267-B","url":null,"abstract":"<div><p>The results of ab initio derivative Hartree-Fock calculations of the dipole and quadrupole shielding polarizabilities and hyperpolarizabilities of a number of small molecules are reported, together with estimates of the electric fields and field gradients present in proteins. It is argued that weak electrical interactions, mediated via these shielding polarizabilities, make major contributions to the chemical-shift nonequivalencies observed in proteins due to folding into their native conformations. The electric-field-induced shifts may be very large (≈5 ppm for <sup>13</sup>C, ≈10 ppm for <sup>17</sup>O and <sup>17</sup>F), due to the low dielectric constants found in proteins, and in some cases they may dominate the experimentally observed spectral shifts.</p></div>","PeriodicalId":100800,"journal":{"name":"Journal of Magnetic Resonance (1969)","volume":"100 2","pages":"Pages 342-357"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-2364(92)90267-B","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90001360","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":"An artificial neural network for classifying cross peaks in two-dimensional NMR spectra","authors":"Simon A Corne, A.Peter Johnson, Julie Fisher","doi":"10.1016/0022-2364(92)90260-E","DOIUrl":"https://doi.org/10.1016/0022-2364(92)90260-E","url":null,"abstract":"<div><p>A simulated neural network is described that has been trained to classify cross peaks in the 2D NMR spectra of biological macromolecules. The trained network has then been used to classify previously unseen data. The network is able to distinguish between authentic cross peaks and spectral artifacts, such as those arising from presaturation of water, noise, and <em>t</em><sub>1</sub> noise. Moreover, the network is able to recognize genuine peaks whose shapes have been modified, for example, by overlap with other real or spurious peaks. Herein, the training and performance of the network are demonstrated for a NOESY spectrum.</p></div>","PeriodicalId":100800,"journal":{"name":"Journal of Magnetic Resonance (1969)","volume":"100 2","pages":"Pages 256-266"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-2364(92)90260-E","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91631627","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}