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PatentDOI

Adiabatic pulses for wideband inversion and broadband decoupling

Eriks Kupče1
26 Jul 1996-Journal of Magnetic Resonance, Series A (Academic Press)-Vol. 115, Iss: 2, pp 273-276
TL;DR: In this article, an inversion pulse for wideband application is obtained from a simple nonlinear amplitude modulation wherein the amplitude is modulated in accord with A(t)=A 0 {1-| sin βt| n } and the entire pulse is frequency modulated such that the phase varies as φ(t) =φ 0 + 1/2 kt 2
About: This article is published in Journal of Magnetic Resonance, Series A.The article was published on 1996-07-26. It has received 538 citations till now. The article focuses on the topics: Amplitude modulation & Amplitude.
Citations
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Journal ArticleDOI
TL;DR: It is found that a stepwise variation of the phase angle in the TPPM sequence offers even better results, and the application of this new method to a liquid crystalline compound and a solid, L-tyrosine hydrochloride, is reported.

1,698 citations

Journal ArticleDOI
TL;DR: The classical adiabatic rapid passage is analyzed using vector models in different rotating frames of reference and ways to tailor modulation functions to best satisfy specific experimental needs are demonstrated.

848 citations


Additional excerpts

  • ...5Tp) [25] F1(t) = tanh(2β(1− t/Tp)) (0....

    [...]

01 Jan 2001
TL;DR: In this article, the classical adiabatic rapid passage is analyzed using vector models in different rotating frames of reference, and two methods to optimize adabaticity are described, and ways to tailor modulation functions to best satisfy specific experimental needs are demonstrated.
Abstract: Frequency-modulated (FM) pulses that function according to adiabatic principles are becoming increasingly popular in many areas of NMR. Often adiabatic pulses can extend experimental capabilities and minimize annoying experimental imperfections. Here, adiabatic principles and some of the current methods used to create these pulses are considered. The classical adiabatic rapid passage, which is a fundamental element upon which all adiabatic pulses and sequences are based, is analyzed using vector models in different rotating frames of reference. Two methods to optimize adiabaticity are described, and ways to tailor modulation functions to best satisfy specific experimental needs are demonstrated. Finally, adiabatic plane rotation pulses and frequency-selective multiple spin-echo sequences are considered.

721 citations

Journal ArticleDOI
TL;DR: It is demonstrated for different protein samples that 2D 1H-15N correlation NMR spectra can be recorded in a few seconds of acquisition time using a new band-selective optimized flip-angle short-transient heteronuclear multiple quantum coherence experiment.
Abstract: We demonstrate for different protein samples that 2D 1H−15N correlation NMR spectra can be recorded in a few seconds of acquisition time using a new band-selective optimized flip-angle short-transient heteronuclear multiple quantum coherence experiment. This has enabled us to measure fast hydrogen−deuterium exchange rate constants along the backbone of a small globular protein fragment by real-time 2D NMR.

587 citations

Journal ArticleDOI
TL;DR: Improved spectra are obtained relative to data recorded with other purging schemes and structural information obtained for a complex of the amino-terminal arginine rich domain of the N protein from bacteriophage λ and boxB RNA using the new methodology is presented.
Abstract: New pulse schemes for recording intermolecular NOEs in a molecular complex consisting of 15N,13C labeled and unlabeled components are presented. The pulse sequences select for magnetization transferred from protons on the unlabeled component to proximal protons of the labeled molecule. Filtering (suppression of signal from 13C labeled molecules) is accomplished using adiabatic 13C inversion pulses which are swept at a rate which is tuned according to the one-bond 1H−13C scalar coupling vs carbon chemical shift profile of the labeled molecule in the complex. Significantly improved spectra are obtained relative to data recorded with other purging schemes. Improvements are demonstrated in experiments where intermolecular NOEs between labeled RNA-unlabeled peptide and labeled protein−unlabeled peptide are recorded. A discussion of structural information obtained for a complex of the amino-terminal arginine rich domain of the N protein from bacteriophage λ and boxB RNA using the new methodology is presented.

582 citations

References
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PatentDOI
TL;DR: In this paper, a radio-frequency pulse is tuned to the frequency of the nuclear species, such as 1 H, to be decoupled or saturated and has a bandwidth adjusted to correspond to the entire chemical shift spectrum, minimizing the amount of radiofrequency power transmitted into a volume of the irradiated sample.

29 citations

Patent
06 Oct 1990
TL;DR: In this article, a method for generating a spectrum of NMR signals with rectangular characteristic in the frequency space by radiating a sequence of RF pulses onto a sample in the homogeneous magnetic field is presented.
Abstract: A method for generating a spectrum of NMR signals with rectangular characteristic in the frequency space by radiating a sequence of RF pulses onto a sample in the homogeneous magnetic field is presented. The RF pulses of the sequence are amplitude modulated and the enveloping function of the sequence consists of a superposition of bell-curve-shaped RF pulses with optimized positions of the maxima, pulse widths and peak amplitudes. The response signals, in dependence on the standardized frequency, shift, approximate virtually ideally, a rectangular function. The method is applicable with success especially in image generation for NMR tomography, in multidimensional NMR spectroscopy, as well as in volume selective NMR spectroscopy.

7 citations

PatentDOI
TL;DR: In this article, the authors proposed a method for broadband decoupling in nuclear magnetic resonance with chirp and other RF pulses, where the sample is placed in a static field, and a first cycle of chirps pulses are generated, followed by a second cycle of pulses generated by a supercycle of the first and second cycles.

6 citations

Patent
08 Dec 1993
TL;DR: In this article, a method for exciting transverse magnetization by irradiating a nuclear spin system subjected to a constant magnetic field with a frequency-modulated rf-pulse ("chirp"-pulse) and with a further frequency-modified rfpulse (further chirppulse), for refocusing the magnetization, is characterized in that the rf pulse-(P1) and the further pulse (P2) overlap each other in time at least partially.
Abstract: A method for exciting transverse magnetization by irradiating a nuclear spin system subjected to a constant magnetic field with a frequency-modulated rf-pulse ("chirp"-pulse) and with a further frequency-modulated rf-pulse (further chirp-pulse) for refocusing the magnetization, is characterized in that the rf-pulse-(P1) and the further rf-pulse (P2) overlap each other in time at least partially. Thus, the duration of the pulses can be reduced.

5 citations

PatentDOI
Michael Deimling1
TL;DR: In this paper, a spin system with a frequency-selective radio-frequency (RF) pulse was used for magnetic resonance spectroscopy and imaging, and the shape of the pulse was optimized.

4 citations