Akishima, Japan
Akishima, Japan

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Patent
Kyoto University and JEOL Resonance Inc. | Date: 2014-02-26

An NMR (nuclear magnetic resonance) detection module (such as an NMR probe) mounted in a vacuum vessel is offered. This module permits a transmit/receive coil to be cooled efficiently and to be placed closer to a sample container. The NMR detection module includes a core module (detection module) (54) consisting of a refrigerant block (118) and a transmit/receive coil formed on the inner surface of a detection hole (130). A sleeve (cylindrical partition wall) (122) forming a part of the vacuum vessel is inserted in the detection hole (130). A sample tube (56) is inserted in the sleeve (122). The refrigerant block (118) is connected to a heat exchanger via a support member (82). Since it is not necessary to form a bobbin inside the transmit/receive coil, the distance between the coil and the sample can be set small. Because the coil is entirely surrounded by the refrigerant block, the coil is cooled efficiently.


Patent
JEOL Resonance Inc. and Kyoto University | Date: 2014-02-26

There is disclosed a cooled NMR detection probe including a detection coil and an internal structure. If the internal structure shrinks, the position of the detection coil can be maintained. The detection coil is cooled sufficiently. The internal structure (65) mounted in a vacuum vessel (58) includes a radiation shield assembly (68), a connecting member (74), and a heat exchanger (80). The internal structure (65) is secured to the vacuum vessel (58) by a holding member (66). The holding member (66) has an elongated portion extending in an up-and-down direction such that inflow of heat via the holding member (66) is reduced to a minimum. A shield body (70) and the connecting member (74) exist in the heat conduction path going from the holding member (66) to the first heat exchanger (80). If the internal structure shrinks during cooling, the position of an upper portion of the first heat exchanger (80) hardly varies, thus suppressing displacement of a core module (54). The elongated portion can deform as the internal structure (65) shrinks (i.e., decreases in diameter).


Parthasarathy S.,University of Illinois at Chicago | Nishiyama Y.,JEOL Resonance Inc. | Ishii Y.,University of Illinois at Chicago
Accounts of Chemical Research | Year: 2013

Recent research in fast magic angle spinning (MAS) methods has drasticallyimproved the resolution and sensitivity of NMR spectroscopy of biomolecules and materials in solids. In this Account, we summarize recent and ongoing developments in this area by presenting 13C and 1H solid-state NMR (SSNMR) studies on paramagnetic systems and biomolecules under fast MAS from our laboratories.First, we describe how very fast MAS (VFMAS) at the spinning speed of at least20 kHz allows us to overcome major difficulties in 1H and 13C high-resolution SSNMR of paramagnetic systems. As a result, we can enhance both sensitivity and resolution by up to a few orders of magnitude. Using fast recycling (∼ms/scan) with short 1H T1 values, we can perform 1H SSNMR microanalysis of paramagnetic systems on the microgram scale with greatly improved sensitivity over that observed for diamagnetic systems. Second, we discuss how VFMAS at a spinning speed greater than ∼40 kHz can enhance the sensitivity and resolution of 13C biomolecular SSNMR measurements. Low-power 1H decoupling schemes under VFMAS offer excellent spectral resolution for 13C SSNMR by nominal 1H RF irradiation at ∼10 kHz. By combining the VFMAS approach with enhanced 1H T 1 relaxation by paramagnetic doping, we can achieve extremely fast recycling in modern biomolecular SSNMR experiments. Experiments with 13C-labeled ubiquitin doped with 10 mM Cu-EDTA demonstrate how effectively this new approach, called paramagnetic assisted condensed data collection (PACC), enhances the sensitivity.Lastly, we examine 13C SSNMR measurements for biomolecules under faster MAS at a higher field. Our preliminary 13C SSNMR data of Aβ amyloid fibrils and GB1 microcrystals acquired at 1H NMR frequencies of 750-800 MHz suggest that the combined use of the PACC approach and ultrahigh fields could allow for routine multidimensional SSNMR analyses of proteins at the 50-200 nmol level. Also, we briefly discuss the prospects for studying bimolecules using 13C SSNMR under ultrafast MAS at the spinning speed of ∼100 kHz. © 2013 American Chemical Society.


Patent
JEOL Resonance Inc. | Date: 2013-10-08

There is disclosed an NMR (nuclear magnetic resonance) spinner having a turbine structure and a rotor whose spinning rate can be increased. A vortical channel (44) is formed around the rotor (12). The vortical channel (44) consists of a chamber (66) and a nozzle array (68) mounted inside the chamber (66). The chamber (66) has a cross-sectional area that decreases in an upstream to downstream direction. The cross-sectional area of each nozzle also decreases in an upstream to downstream direction. Gas is introduced into the chamber (66), creating a rotating flow (76, 78, 80) in the chamber (66). Plural inwardly swirling streams are created from the inside of the rotating flow. The inwardly swirling streams are ejected from the exits of the nozzles. This results in jet streams, which are blown against the impeller of the rotor, spinning the rotor at high speed.


Patent
JEOL Resonance Inc. | Date: 2014-04-16

There is disclosed an NMR (nuclear magnetic resonance) spinner having a turbine structure and a rotor whose spinning rate can be increased. A vortical channel (44) is formed around the rotor (12). The vortical channel (44) consists of a chamber (66) and a nozzle array (68) mounted inside the chamber (66). The chamber (66) has a cross-sectional area that decreases in an upstream to downstream direction. The cross-sectional area of each nozzle also decreases in an upstream to downstream direction. Gas is introduced into the chamber (66), creating a rotating flow (76, 78, 80) in the chamber (66). Plural inwardly swirling streams are created from the inside of the rotating flow. The inwardly swirling streams are ejected from the exits of the nozzles. This results in jet streams, which are blown against the impeller of the rotor, spinning the rotor at high speed.


Patent
JEOL Resonance Inc. | Date: 2014-03-12

A method of NMR measurement is offered which achieves background suppression based on a technique employing differences in RF magnetic field strength while alleviating the problem that less latitude is allowed in setting the number of signal accumulations. This method suppresses a background-derived signal emanating from the material of an NMR probe. The method starts with applying an RF pulse sequence consisting of a 90 pulse and subsequent one or more 180 pulses to a sample to induce an NMR signal and detecting the signal. This application is repeated while varying the RF phases of the pulses to induce NMR signals in accordance with a cogwheel phase-cycling scheme to induce NMR signals. The NMR signals are detected. The detected NMR signals are accumulated.


In a magnetic resonance measurement apparatus, when a frequency of an observation nucleus falls within a high frequency band, a frequency conversion scheme is selected. In this case, an intermediate frequency signal is generated as an original signal, which is then frequency-converted to generate an RF transmission signal. An RF reception signal is converted into an intermediate frequency signal by frequency conversion, and is sampled. When the frequency of the observation nucleus falls within a low frequency band, a non-conversion scheme is selected. In this case, an RF transmission signal is generated as the original signal, and an RF reception signal is sampled.


Procedure instruction sequences (P_(1)P_(N)) in an instruction sequence (for example, an instruction sequence for an NMR spectrometer) are generated in a precedential manner, and transferred to a procedure storage area on a transmission and reception unit in a precedential manner. After the precedential transfer, a remaining portion of the instruction sequence (streaming instruction sequence (S_(M1), . . . )) is sequentially generated in predetermined units from the beginning, and sequentially transferred to a FIFO area on the transmission and reception unit. A sequencer refers to the streaming instruction sequence, executes the instruction, and refers to a procedure instruction sequence on the procedure storage area.


In a magnetic resonance measurement apparatus such as an NMR measurement apparatus, when a frequency of an observation nucleus falls within a high frequency band, an RF reception signal is converted into an intermediate frequency signal, and is input to an analog-to-digital converter. In this case, under-sampling is executed for the intermediate frequency signal in the analog-to-digital converter, and a second-order aliased signal component generated from a target signal component is observed. On the other hand, when the frequency of the observation nucleus falls within a low frequency band, over-sampling for the RF reception signal is executed.


In a magnetic resonance measurement apparatus, a plurality of transmission signals are combined to generate a digital combined signal. The digital combined signal is converted into an analog combined signal by a D/A converter. The signal includes, for example, a first pulse of a rectangular shape and a second pulse of a mountain shape. During measurement, an operation of a dynamic variable attenuator is changed immediately after the first pulse. With this process, the second pulse is suppressed, and a suppressed second pulse is generated.

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