Journal of Magnetic Resonance, Series B最新文献

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Determination of the Chemical-Shift Difference between the Lactate Multiplets and Its pH Dependence 乳酸多胞胎化学位移差的测定及其对pH值的依赖性
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0136
Michael Bunse , Wulf-Ingo Jung , Günther Dietze , Otto Lutz
{"title":"Determination of the Chemical-Shift Difference between the Lactate Multiplets and Its pH Dependence","authors":"Michael Bunse ,&nbsp;Wulf-Ingo Jung ,&nbsp;Günther Dietze ,&nbsp;Otto Lutz","doi":"10.1006/jmrb.1996.0136","DOIUrl":"10.1006/jmrb.1996.0136","url":null,"abstract":"<div><p>A volume-selective NMR method is presented for very exact determination of the difference of the Larmor frequencies between the coupled resonances of homonuclear AX<sub>3</sub>spin systems, as, for example, lactate. The frequency difference can be determined with an accuracy of 0.003 ppm even if only the doublet of the spin system can be detected. The method is based on the effects of homonuclear polarization transfer which occurs in localized double-spin-echo spectroscopy. It is used for determination of the chemical-shift difference of the lactate multiplets, which depends on the degree of dissociation and consequently on pH. Measurements were performed with a 1.5 T Siemens Magnetom SP 63 whole-body imager on solutions of lactate and acetic acid in physiological sodium chloride solution with pH from 1 to 11. As a consequence of these measurements, conclusions are possible for the optimum echo time for PRESS measurements which avoid signal losses from polarization transfer. Furthermore, the possibility of localized pH determination by this effect is discussed.</p></div>","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Pages 236-239"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0136","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19781598","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}
引用次数: 3
Measuring Diffusion in the Presence of Material Strain 材料应变存在下的扩散测量
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0139
Timothy G. Reese, Van J. Wedeen, Robert M. Weisskoff
{"title":"Measuring Diffusion in the Presence of Material Strain","authors":"Timothy G. Reese,&nbsp;Van J. Wedeen,&nbsp;Robert M. Weisskoff","doi":"10.1006/jmrb.1996.0139","DOIUrl":"10.1006/jmrb.1996.0139","url":null,"abstract":"<div><p>Material strain during the course of diffusion encoding by MRI will in general change the observed diffusional signal losses. These changes will occur even when the material returns cyclically to its initial location during the diffusion-evolution period. This effect derives from the modification of the local spatial modulation k of spin phase within a sample by a material deformation fontserif=cmss10 at 10pt[formula]as k →[formula]k, resulting in an observed diffusion tensor[formula]where[formula]is the material stretch tensor. For example, when a material is compressed during pulsed-gradient diffusion encoding, the compression acts to increase the attenuation due to diffusion just as if a larger gradient were used. By using a simple gelatin phantom, the existence of this effect is demonstrated, and an effective method for its correction based on an MRI mapping of the material strain is presented. This correction is particularly relevant for inferring myofiber structure in the beating<em>in vivo</em>human heart, since the measurement of[formula]is perturbed by the deformation of myocardium during the heart's contraction.</p></div>","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Pages 253-258"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0139","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19781601","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}
引用次数: 73
Measurement of Amide15N–1H One-Bond Couplings in Proteins Using Accordion Heteronuclear-Shift-Correlation Experiments 用手风琴异核位移相关实验测量蛋白质中酰胺15n - 1h单键偶联
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0141
J.R. Tolman, J.H. Prestegard
{"title":"Measurement of Amide15N–1H One-Bond Couplings in Proteins Using Accordion Heteronuclear-Shift-Correlation Experiments","authors":"J.R. Tolman,&nbsp;J.H. Prestegard","doi":"10.1006/jmrb.1996.0141","DOIUrl":"10.1006/jmrb.1996.0141","url":null,"abstract":"","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Pages 269-274"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0141","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19887339","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}
引用次数: 48
Optimization of Transverse Gradient Coils with Coaxial Return Paths by Simulated Annealing 用模拟退火法优化具有同轴返回路径的横向梯度线圈
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0133
M.L. Buszko , M.F. Kempka , E. Szczesniak , D.C. Wang , E.R. Andrew
{"title":"Optimization of Transverse Gradient Coils with Coaxial Return Paths by Simulated Annealing","authors":"M.L. Buszko ,&nbsp;M.F. Kempka ,&nbsp;E. Szczesniak ,&nbsp;D.C. Wang ,&nbsp;E.R. Andrew","doi":"10.1006/jmrb.1996.0133","DOIUrl":"10.1006/jmrb.1996.0133","url":null,"abstract":"<div><p>Coils with coaxial return paths are used to generate transverse magnetic field gradients. This paper describes optimization of such coils by the method of simulated annealing, a method known to be able to find the global minimum of a function. The adaptive simulated annealing (ASA) program has been analyzed and applied to optimization of a family of coils with 8–16 building blocks, each carrying equal current. Positions of the blocks along the longitudinal axis of the coils were optimized. A new subclass of coils is proposed; the diameter of return paths of this subclass of coils is not fixed but may be varied. The new coils provide greater gradient uniformity than those for which only positions of the blocks are optimized. All optimized coils should find applications in high-precision and high-resolution imaging and spectroscopic experiments.</p></div>","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Pages 207-213"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19781166","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}
引用次数: 16
Chemical-Shift-Selective Acquisition of Multiple-Quantum-Filtered23Na Signal 多量子滤波23na信号的化学位移选择性采集
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0134
K.J. Jung , J. Katz
{"title":"Chemical-Shift-Selective Acquisition of Multiple-Quantum-Filtered23Na Signal","authors":"K.J. Jung ,&nbsp;J. Katz","doi":"10.1006/jmrb.1996.0134","DOIUrl":"10.1006/jmrb.1996.0134","url":null,"abstract":"<div><p>Equations describing the multiple-quantum (MQ) signal produced by an MQ pulse sequence are systematically derived in both absence and presence of refocusing RF pulses. When the RF pulses in an MQ pulse sequence satisfy certain conditions, these equations may be arranged in a factorized form. The off-resonance effects on the MQ signal due to chemical shift can then be analyzed separately during the preparation and evolution times. Using the reformulated equations, the dependence of the amplitude of an MQ signal on the phase shift induced by the resonance offset during the preparation and evolution times is demonstrated. By use of the new equations, it is shown that the off-resonance effects, occurring during both the preparation and evolution times, may be described in terms of the same physical process, i.e., interference between echo and antiecho. In applying the off-resonance effects for the elimination of the MQ signal in the presence of chemical shift, it is possible to suppress the MQ signal over a wider off-resonance bandwidth by use of the nonrefocused preparation and evolution times than by use of a single time. Furthermore, by taking an alternative approach in deriving the equations, the interference between echo and antiecho due to the resonance offset is shown to be insensitive to the flip angle of the creation RF pulse (usually the second π/2 RF pulse). The theoretical findings were experimentally verified by use of a phantom containing sodium in agarose.</p></div>","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Pages 214-227"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0134","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19781167","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}
引用次数: 6
Interaction of Daunomycin with Dipalmitoylphosphatidylcholine Model Membranes. A1H NMR Study 道诺霉素与双棕榈酰磷脂酰胆碱模型膜的相互作用。核磁共振研究
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0135
Luigi Calzolai, Elena Gaggelli, Antonella Maccotta, Gianni Valensin
{"title":"Interaction of Daunomycin with Dipalmitoylphosphatidylcholine Model Membranes. A1H NMR Study","authors":"Luigi Calzolai,&nbsp;Elena Gaggelli,&nbsp;Antonella Maccotta,&nbsp;Gianni Valensin","doi":"10.1006/jmrb.1996.0135","DOIUrl":"10.1006/jmrb.1996.0135","url":null,"abstract":"<div><p><sup>1</sup>H NMR parameters were obtained for daunomycin in water solution in the free state as well as in the presence of dipalmitoylphosphatidylcholine model membranes. Spin–lattice relaxation rates were measured under nonselective, single-selective, and double-selective irradiation modes, and 2D NOESY spectra were obtained at several values of the mixing time. Proton–proton distances were calculated and the motional correlation time was evaluated in both the free and bound states. NMR parameters were used to show that ring A and the glucosamine moiety of daunomycin strongly interact with the external surface of the bilayer, while the rest of the molecule penetrates the membrane without crossing it. The structures of both free and bound daunomycin were obtained and compared by using molecular modeling.</p></div>","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Pages 228-235"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0135","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19781168","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}
引用次数: 9
Phase-Sensitive Two-Dimensional Heteronuclear Zero- and Double-Quantum-Coherence Spectroscopy 相敏二维异核零和双量子相干光谱学
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0137
Jüri Jarvet , Peter Allard
{"title":"Phase-Sensitive Two-Dimensional Heteronuclear Zero- and Double-Quantum-Coherence Spectroscopy","authors":"Jüri Jarvet ,&nbsp;Peter Allard","doi":"10.1006/jmrb.1996.0137","DOIUrl":"10.1006/jmrb.1996.0137","url":null,"abstract":"<div><p>New pulse sequences for two-dimensional phase-sensitive detection of heteronuclear zero- and double-quantum coherence are presented for use with and without pulsed field gradients. The magnetization is phase modulated during<em>t</em><sub>1</sub>and then transferred to a proton for detection using a novel approach similar to the sensitivity-enhancement technique [Palmer<em>et al. J. Magn. Reson.</em>93, 151 (1991)]. These pulse sequences are useful for the measurement of size and relative sign of passive<em>J</em>couplings as well as for the measurement of the relaxation rates of zero- and double-quantum coherence. They can also be used as building blocks in multidimensional pulse sequences. The pulse sequences are tested on the peptide hormone motilin with a selectively<sup>13</sup>C-enriched α carbon.</p></div>","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Pages 240-244"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0137","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19781599","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}
引用次数: 10
Author Index for Volume 112 第112卷作者索引
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0147
{"title":"Author Index for Volume 112","authors":"","doi":"10.1006/jmrb.1996.0147","DOIUrl":"https://doi.org/10.1006/jmrb.1996.0147","url":null,"abstract":"","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Page 307"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0147","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136730250","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}
引用次数: 0
CW and Pulsed EPR Characterization of the Reduction of the Rieske-Type Iron–Sulfur Cluster in 2,4,5-Trichlorophenoxyacetate Monooxygenase 2,4,5-三氯苯氧乙酸单加氧酶还原rieske型铁-硫簇的连续波和脉冲EPR表征
Journal of Magnetic Resonance, Series B Pub Date : 1996-09-01 DOI: 10.1006/jmrb.1996.0144
Sergei A. Dikanov , Roman M. Davydov , Luying Xun , Michael K. Bowman
{"title":"CW and Pulsed EPR Characterization of the Reduction of the Rieske-Type Iron–Sulfur Cluster in 2,4,5-Trichlorophenoxyacetate Monooxygenase","authors":"Sergei A. Dikanov ,&nbsp;Roman M. Davydov ,&nbsp;Luying Xun ,&nbsp;Michael K. Bowman","doi":"10.1006/jmrb.1996.0144","DOIUrl":"10.1006/jmrb.1996.0144","url":null,"abstract":"","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 3","pages":"Pages 289-294"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0144","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19781603","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}
引用次数: 7
Magnetic Resonance Imaging for the Determination of Magnetic Susceptibility of Materials 磁共振成像测定材料磁化率
Journal of Magnetic Resonance, Series B Pub Date : 1996-08-01 DOI: 10.1006/jmrb.1996.0120
O. Beuf , A. Briguet , M. Lissac , R. Davis
{"title":"Magnetic Resonance Imaging for the Determination of Magnetic Susceptibility of Materials","authors":"O. Beuf ,&nbsp;A. Briguet ,&nbsp;M. Lissac ,&nbsp;R. Davis","doi":"10.1006/jmrb.1996.0120","DOIUrl":"10.1006/jmrb.1996.0120","url":null,"abstract":"<div><p>A magnetic resonance imaging method for volume magnetic susceptibility estimate of materials immersed in a liquid containing resonant nuclei is proposed. The method uses either the standard spin-echo Fourier imaging technique or the projection-reconstruction technique. Image distortions of cylindrical macroscopic susceptibility inhomomogeneities are analyzed and a correlation is established between the susceptibility value and the size of image deformation along the read gradient. For measurements, the susceptibility of the liquid surrounding the sample (here deionized water) serves as a reference, and characteristic distances between particular points, usually highlights in the distorted image, are related to the susceptibility difference between the two media. Different samples, mainly prosthetic materials with a large susceptibility range from 5 to 200 ppm in absolute value, have been investigated, and the accuracy of susceptibility determination is discussed.</p></div>","PeriodicalId":16130,"journal":{"name":"Journal of Magnetic Resonance, Series B","volume":"112 2","pages":"Pages 111-118"},"PeriodicalIF":0.0,"publicationDate":"1996-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmrb.1996.0120","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19781207","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}
引用次数: 65
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