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Concepts in magnetic resonance最新文献

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The NOE factor in heteronuclear A { X 2 }, A { XX '}, A { XY } spin- 1 2 systems 异核A {x2}， A {XX '}， A {XY}自旋- 12体系的NOE因子
Concepts in magnetic resonance Pub Date : 1999-04-01 DOI: 10.1002/(SICI)1099-0534(1999)11:3<111::AID-CMR1>3.3.CO;2-U
D. Canet
{"title":"The NOE factor in heteronuclear A { X 2 }, A { XX '}, A { XY } spin- 1 2 systems","authors":"D. Canet","doi":"10.1002/(SICI)1099-0534(1999)11:3<111::AID-CMR1>3.3.CO;2-U","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1999)11:3<111::AID-CMR1>3.3.CO;2-U","url":null,"abstract":"","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"91 2","pages":"111-119"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50681302","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: 1
Multipulse NMR part III. INADEQUATE pulse sequence 多脉冲核磁共振第三部分。脉冲序列不充分
Concepts in magnetic resonance Pub Date : 1999-03-01 DOI: 10.1002/(SICI)1099-0534(1999)11:2<97::AID-CMR4>3.3.CO;2-5
I. S. Podkorytov
{"title":"Multipulse NMR part III. INADEQUATE pulse sequence","authors":"I. S. Podkorytov","doi":"10.1002/(SICI)1099-0534(1999)11:2<97::AID-CMR4>3.3.CO;2-5","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1999)11:2<97::AID-CMR4>3.3.CO;2-5","url":null,"abstract":"This is the concluding part of a short introduction to multipulse NMR. The product operator formalism considered in Parts I and II (Concepts Magn. Reson., 1996, 8, 17–32; 1997, 9,117–137) is applied to the description of the INADEQUATE (incredible natural-abundance double-quantum experiment) pulse sequence. The basic one-dimensional INADEQUATE pulse technique, two-dimensional and selective modifications of this method, and the INADEQUATE with composite-refocusing pulse train are discussed. ©1999 John Wiley & Sons, Inc. Concepts Magn Reson 11: 97–110, 1999","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"95 5","pages":"97-110"},"PeriodicalIF":0.0,"publicationDate":"1999-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50681277","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: 2
Magnetization transfer experiments employing continuous RF fields 采用连续射频场的磁化转移实验
Concepts in magnetic resonance Pub Date : 1999-03-01 DOI: 10.1002/(SICI)1099-0534(1999)11:2<89::AID-CMR3>3.3.CO;2-3
E. Johnston
{"title":"Magnetization transfer experiments employing continuous RF fields","authors":"E. Johnston","doi":"10.1002/(SICI)1099-0534(1999)11:2<89::AID-CMR3>3.3.CO;2-3","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1999)11:2<89::AID-CMR3>3.3.CO;2-3","url":null,"abstract":"","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"102 4","pages":"89-95"},"PeriodicalIF":0.0,"publicationDate":"1999-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50681195","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: 2
Direct determination of quadrupolar and dipolar NMR correlation times from spin-lattice and spin-spin relaxation rates 从自旋-晶格和自旋-自旋弛豫速率直接测定四极和偶极核磁共振相关时间
Concepts in magnetic resonance Pub Date : 1999-01-01 DOI: 10.1002/(SICI)1099-0534(1999)11:1<51::AID-CMR3>3.3.CO;2-V
W. R. Carper
{"title":"Direct determination of quadrupolar and dipolar NMR correlation times from spin-lattice and spin-spin relaxation rates","authors":"W. R. Carper","doi":"10.1002/(SICI)1099-0534(1999)11:1<51::AID-CMR3>3.3.CO;2-V","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1999)11:1<51::AID-CMR3>3.3.CO;2-V","url":null,"abstract":"Recent developments in the mathematical solution of nuclear magnetic resonance (NMR) relaxation equations describing rotational motion allow investigators to determine correlation times, τ, on the nanosecond time scale. NMR rotational correlation equations for quadrupolar and dipolar relaxation can be solved for nuclei in moderately viscous media using R2/R1 ratios. In the case of quadrupolar nuclei, the R2/R1 ratios can be used to solve the rotational correlation equations directly. For dipolar nuclei including 1H, 13C, 15N, 19F, 31P, and 113Cd, it is necessary to solve the rotational correlation time equations at each magnetic field strength using iterative methods. The resulting solutions are fitted to pairs of polynomials (R2/R1=1.1–20 and 20–1200) at individual magnetic field strengths (4.7, 6.35, 7.05, 9.4, 11.75, and 14.1 T). The investigator determines the R2/R1 ratio at a specific magnetic field and uses the appropriate polynomial to determine the rotational correlation time. Correlation times are used to study molecular interactions where dipolar relaxtion occurs and to determine quadrupole coupling constants, χ, where quadrupole relaxation is the predominant mechanism. 1H-NMR diffusion constants can be compared with NMR correlation times to provide data about the transport properties of the system being studied. ©1999 John Wiley & Sons, Inc. Concepts Magn Reson 11: 51–60, 1999","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"12 4","pages":"51-60"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50681256","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: 15
Signal intensities and T 1 calculations in multiple-echo sequences with imperfect pulses 不完全脉冲多重回波序列的信号强度和t1计算
Concepts in magnetic resonance Pub Date : 1999-01-01 DOI: 10.1002/(SICI)1099-0534(1999)11:1<29::AID-CMR2>3.3.CO;2-D
P. Kingsley
{"title":"Signal intensities and T 1 calculations in multiple-echo sequences with imperfect pulses","authors":"P. Kingsley","doi":"10.1002/(SICI)1099-0534(1999)11:1<29::AID-CMR2>3.3.CO;2-D","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1999)11:1<29::AID-CMR2>3.3.CO;2-D","url":null,"abstract":"Formulas are derived for longitudinal magnetization in multiple-echo inversion recovery (IR), saturation recovery, and progressive saturation pulse sequences with imperfect pulses. The effects of imperfect pulses on the signal intensities and on the calculated T1 relaxation times are discussed. Relaxation data from all three methods can be fitted with an equation of the form: Signal intensity=[a+b exp(−TX/T1)]/[1+c exp(−TX/T1)], where TX is a variable delay time and the values of T1, a, b, and c are adjusted to optimize the fit. Only three parameters need to be fitted for progressive saturation with no echoes because b=−a. For modified fast IR (with constant repetition time TR), c=0 and a three-parameter fit suffices even if several non–steady-state signals are acquired and a range of flip angles is present within the sample. The advantages of the modified fast IR method for multiple-slice measurements of T1 in magnetic resonance imaging (MRI) are reviewed. Other applications of these formulas include estimating errors in T1 calculations, finding the flip angles (“Ernst angles”), echo spacing, and TR that maximize the signal-to-noise ratio in multiple-echo sequences, optimizing contrast between tissues in MRI, and determining how quickly a steady state is approached. ©1999 John Wiley & Sons, Inc. Concepts Magn Reson 11: 29–49, 1999","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"27 2","pages":"29-49"},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50680764","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: 52
Resolution improvement in NMR spectra: application and significance of chemical shift upscaling in multidimensional NMR experiments 核磁共振光谱分辨率的提高:化学位移上尺度在多维核磁共振实验中的应用及意义
Concepts in magnetic resonance Pub Date : 1998-10-01 DOI: 10.1002/(SICI)1099-0534(1998)10:6<355::AID-CMR3>3.3.CO;2-Y
P. Khandelwal, A. Majumdar, R. Hosur
{"title":"Resolution improvement in NMR spectra: application and significance of chemical shift upscaling in multidimensional NMR experiments","authors":"P. Khandelwal, A. Majumdar, R. Hosur","doi":"10.1002/(SICI)1099-0534(1998)10:6<355::AID-CMR3>3.3.CO;2-Y","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1998)10:6<355::AID-CMR3>3.3.CO;2-Y","url":null,"abstract":"An analysis of resolution in nuclear magnetic resonance (NMR) spectra in terms of separation, linewidth, and limited digitization capability is presented. The effect of scaling up of frequencies on resolution is considered, and criteria useful for determining whether two peaks are resolvable in continuous-wave and digitized spectra are derived. Finally, a new pulse sequence based on upscaling of chemical shifts is described for resolution improvement along the F1 dimension in heteronuclear correlation NMR spectra. The performance of the sequence is demonstrated by experimental data on large proteins, and simulations are performed for its optimization. ©1998 John Wiley & Sons, Inc. Concepts Magn Reson 10: 355–368, 1998","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"40 3","pages":"355-368"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50680574","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: 1
Counting echoes: application of a complete reciprocal-space description of NMR spin dynamics 计数回声:核磁共振自旋动力学的完全互向空间描述的应用
Concepts in magnetic resonance Pub Date : 1998-10-01 DOI: 10.1002/(SICI)1099-0534(1998)10:6<331::AID-CMR1>3.3.CO;2-H
Richard J. Nelson, Y. Maguire, Daniel F. Caputo, G. Leu, Yun-Ju Kang, M. Pravia, D. Tuch, Y. Weinstein, David G. Cory
{"title":"Counting echoes: application of a complete reciprocal-space description of NMR spin dynamics","authors":"Richard J. Nelson, Y. Maguire, Daniel F. Caputo, G. Leu, Yun-Ju Kang, M. Pravia, D. Tuch, Y. Weinstein, David G. Cory","doi":"10.1002/(SICI)1099-0534(1998)10:6<331::AID-CMR1>3.3.CO;2-H","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1998)10:6<331::AID-CMR1>3.3.CO;2-H","url":null,"abstract":"","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"7 1","pages":"331-341"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50680021","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
Measurement of translational molecular diffusion using ultrahigh magnetic field gradient NMR 利用超高磁场梯度核磁共振测量平移分子扩散
Concepts in magnetic resonance Pub Date : 1998-08-01 DOI: 10.1002/(SICI)1099-0534(1998)10:5<299::AID-CMR3>3.3.CO;2-O
B. Geil
{"title":"Measurement of translational molecular diffusion using ultrahigh magnetic field gradient NMR","authors":"B. Geil","doi":"10.1002/(SICI)1099-0534(1998)10:5<299::AID-CMR3>3.3.CO;2-O","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1998)10:5<299::AID-CMR3>3.3.CO;2-O","url":null,"abstract":"Nuclear magnetic resonance field gradient methods provide a powerful tool with which to study translational molecular diffusion. Techniques described use the huge static field gradients available in the stray field of superconducting magnets or in specially designed anti-Helmholtz magnets. The experimental concepts and the dynamical ranges of these methods are discussed in detail and carefully compared with established pulsed-field gradient methods. Large-magnitude static field gradients combined with short radiofrequency-pulse spacings give access to very small diffusion coefficients (down to 10−15 m2 s−1) and a high spatial resolution (molecular displacements down to 10 nm). The advantages of static field gradient techniques are demonstrated with several experimental applications selected from the fields of polymer physics, supercooled melts, and biomedical research. ©1998 John Wiley & Sons, Inc. Concepts Magn Reson 10: 299–321, 1998","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"41 6","pages":"299-321"},"PeriodicalIF":0.0,"publicationDate":"1998-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50680118","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: 50
On the calculation of spectral density functions for spin interactions without axial symmetry 非轴对称自旋相互作用谱密度函数的计算
Concepts in magnetic resonance Pub Date : 1998-08-01 DOI: 10.1002/(SICI)1099-0534(1998)10:5<291::AID-CMR2>3.3.CO;2-E
D. Canet
{"title":"On the calculation of spectral density functions for spin interactions without axial symmetry","authors":"D. Canet","doi":"10.1002/(SICI)1099-0534(1998)10:5<291::AID-CMR2>3.3.CO;2-E","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1998)10:5<291::AID-CMR2>3.3.CO;2-E","url":null,"abstract":"","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"46 11","pages":"291-297"},"PeriodicalIF":0.0,"publicationDate":"1998-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50680005","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: 14
Introduction to rotational-echo, double-resonance NMR 旋转回声、双共振核磁共振简介
Concepts in magnetic resonance Pub Date : 1998-08-01 DOI: 10.1002/(SICI)1099-0534(1998)10:5<277::AID-CMR1>3.3.CO;2-1
T. Gullion
{"title":"Introduction to rotational-echo, double-resonance NMR","authors":"T. Gullion","doi":"10.1002/(SICI)1099-0534(1998)10:5<277::AID-CMR1>3.3.CO;2-1","DOIUrl":"https://doi.org/10.1002/(SICI)1099-0534(1998)10:5<277::AID-CMR1>3.3.CO;2-1","url":null,"abstract":"Rotational-echo, double-resonance nuclear magnetic resonance (REDOR) is a magic-angle spinning experiment for measuring internuclear distances between heteronuclear spin pairs. The basic principles of the REDOR technique are presented. The experimental requirements necessary for quantitative REDOR measurements are also provided. ©1998 John Wiley & Sons, Inc. Concepts Magn Reson 10: 277–289, 1998","PeriodicalId":89665,"journal":{"name":"Concepts in magnetic resonance","volume":"52 7","pages":"277-289"},"PeriodicalIF":0.0,"publicationDate":"1998-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50680315","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: 144
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