scholarly journals Study on the Effects of Sorbitol on Water Holding Capacity of Meat by NMR

2021 ◽  
Author(s):  
Xiaolei Yan ◽  
Bin Du ◽  
Juan Lu ◽  
Wenkun Zhang
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Free Water ◽  
Fresh Meat ◽  
Low Field ◽  
Test Parameters ◽  
Sampling Points ◽  
Repetition Time ◽  
Echo Time ◽  
Water Holding

The distribution and changes of constitutional water, immobilized water and free water and the effects of the sorbitol on three kinds of water during the curing of fresh meat were studied in this paper. The low-field Nuclear Magnetic Resonance were used to measure water and its distribution in meat. The test parameters are as follows: magnetic field strength of the NMR spectrometer is 0.5Tesla, corresponding resonance frequency for protons is 22MHz, sampling points is 160128, repeated scanning number is 16, repetition time is 1.6s, echo time is 1.6s. The results showed that: the relaxation time T2 can be divided into three parts: T21 (0∼10ms), T22 (10∼100ms), T23 (100∼1000ms). And the area of T21, T22, T23 represents the contents of constitutional water, immobilized water and free water. The addition of sorbitol can keep water during curing. The sorbitol can reduce the activity of the immobilized water and free water during curing of the fresh meat.

scholarly journals Effective Suppression of Residual Magnetic Interference in a Conductive Shielded Room for Ultra-Low Field Nuclear Magnetic Resonance

2020 ◽  
Vol 10 (11) ◽  
pp. 3745
Author(s):  
Yiqiu Tan ◽  
Danfeng Zhou ◽  
Mengxiao Song ◽  
Jie Li
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Eddy Currents ◽  
Small Scale ◽  
Signal Loss ◽  
Low Field ◽  
Residual Magnetic Field ◽  
Control Electronics ◽  
Nuclear Magnetic

Residual magnetic interference induced by applied magnetic field pulses inside a conductive shielded room (SR) has been a common issue in ultra-low-field (ULF) nuclear magnetic resonance (NMR). The rapid cutoff of the applied pre-polarizing field (Bp) induces eddy currents in the walls of the SR, which produces a decaying residual magnetic interference that may cause severe image distortions and signal loss. In this study, a pair of cancellation coils (CC) and control electronics were designed for the suppression of the residual magnetic interference in a SR. Simulations show that this method was effective in suppressing the residual magnetic field (Br) after removal of the pre-polarizing magnetic field. Then, a small-scale SR was designed and the effectiveness of this cancellation scheme was experimentally verified. The test results showed a good agreement with the simulation, which indicated that the cancellation scheme was capable of reducing Br field to a much lower level. The scheme proposed in this study provides a solution for suppressing the residual magnetic field in the ULF NMR system. After decoupling the eddy–current field, the effect of the suppression may be further improved by optimization of the cancellation coil in further work.

scholarly journals Pulsed magnetic field generation suited for low-field unilateral nuclear magnetic resonance systems

AIP Advances ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 056814 ◽  
Author(s):  
Neelam Prabhu Gaunkar ◽  
Jayaprakash Selvaraj ◽  
Wei-Shen Theh ◽  
Robert Weber ◽  
Mani Mina
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pulsed Magnetic Field ◽  
Magnetic Field Generation ◽  
Field Generation ◽  
Low Field ◽  
Nuclear Magnetic

scholarly journals The states of water in Norway spruce (Picea abies (L.) Karst.) studied by low-field nuclear magnetic resonance (LFNMR) relaxometry: assignment of free-water populations based on quantitative wood anatomy

Holzforschung ◽  
2017 ◽  
Vol 71 (1) ◽  
pp. 77-90 ◽  
Author(s):  
Maria Fredriksson ◽  
Lisbeth Garbrecht Thygesen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Cell Wall ◽  
Magnetic Resonance ◽  
Picea Abies ◽  
Wood Anatomy ◽  
Free Water ◽  
Sorption Isotherms ◽  
The Other ◽  
Low Field ◽  
Water Saturated

Abstract Low-field nuclear magnetic resonance (LFNMR) relaxometry was applied to determine the spin-spin relaxation time (T2) of water-saturated Norway spruce (Picea abies (L.) Karst.) specimens cut from mature sapwood (sW) and mature and juvenile heartwood (hW), where earlywood (EW) and latewood (LW) were separated. In combination with quantitative wood anatomy data focusing on the void volumes in various morphological regions, the NMR data served for a more reliable assignment of free-water populations found in water-saturated solid wood. Two free-water populations were identified within most sample types. One was assigned to water in the tracheid lumen and the other to water inside bordered pits. Whether water in the ray cell lumina was included in one or the other of these two populations depends on the curve-fit method applied (continuous or discrete). In addition, T2 differences between the different tissue types were studied and, for comparison, sorption isotherms were measured by means of a sorption balance. There was a significant difference between EW and LW as well as between juvenile wood and mature wood in terms of T2 related to the cell wall water. However, no differences were seen between the sorption isotherms, which indicates that the observed T2 differences were not due to differences in cell wall moisture content (MC).

scholarly journals Effects of Hydrocolloid Injection on the Eating Quality of Pork Analyzed Based on Low-Field Nuclear Magnetic Resonance (LF-NMR)

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Shengmei Gai ◽  
Zhonghui Zhang ◽  
Yufeng Zou ◽  
Dengyong Liu
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Distribution ◽  
Free Water ◽  
Color Difference ◽  
Eating Quality ◽  
Low Field ◽  
Lf Nmr ◽  
Nuclear Magnetic

This study investigated the effects of hydrocolloid injection on the eating quality of porcine meat based on low-field nuclear magnetic resonance (LF-NMR). The eating quality and water distribution of hydrocolloid-injected pork were compared with control, and the principle component analysis (PCA) was applied for the identification of hydrocolloid-injected pork. Total color difference (ΔE∗), cooking loss, and moisture content of hydrocolloid-injected pork were significantly increased compared with the control (p<0.05). LF-NMR indicated that significant differences in the relaxation time and peak area proportion of immobilized water (T21, P21) and free water (T22, P22) were detected among hydrocolloid-injected samples and the control (p<0.05). The first two principal components (PCs) of PCA accounted for 54.07% and 33.56% of the observed variation, respectively. Based on the two PCs, the hydrocolloid-injected pork could be differentiated from the control. Therefore, LF-NMR combined with PCA offers an effective method for the analysis and detection of hydrocolloid-injected pork.

Using low-field NMR and MRI to characterize water status and distribution in modified wood during water absorption

Holzforschung ◽  
2019 ◽  
Vol 73 (11) ◽  
pp. 997-1004 ◽  
Author(s):  
Wang Wang ◽  
Jinyu Chen ◽  
Jinzhen Cao
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Absorption ◽  
Loblolly Pine ◽  
Combined Treatment ◽  
Free Water ◽  
Paraffin Wax ◽  
Low Field ◽  
First Case ◽  
Nuclear Magnetic

Abstract In this study, synergism between two wood modification methods was investigated with the aim of providing insights into improving wood hydrophobicity. Loblolly pine (Pinus taeda) was modified using two variants of the same treatment procedure: in the first case, paraffin wax emulsion (PWE) impregnation was followed by thermal modification (TM); in the second case, the order was reversed, and TM was followed by PWE impregnation. The treated samples were then immersed in distilled water for 1, 6, 24, 48 or 96 h. Low-field nuclear magnetic resonance (LF-NMR) and nuclear magnetic resonance imaging (MRI) were employed to evaluate the concentration of different water components, as well as the water distribution. The results indicated that the combined treatment showed much better performance than either treatment individually, particularly when PWE impregnation was followed by TM. Moreover, through the use of MRI, we characterized the role of both methods in the synergistic relationship, which showed that the PWE impregnation increased the wood hydrophobicity through decreasing free water absorption, while the TM performed the same function through bound water absorption. In addition, paraffin wax penetrated the newly formed cracks caused by TM, which also contributed to the synergistic mechanism between PWE impregnation and TM.

scholarly journals Surprising absence of strong homonuclear coupling at low magnetic field explored by two-field nuclear magnetic resonance spectroscopy

2020 ◽  
Vol 1 (2) ◽  
pp. 237-246
Author(s):  
Ivan V. Zhukov ◽  
Alexey S. Kiryutin ◽  
Ziqing Wang ◽  
Milan Zachrdla ◽  
Alexandra V. Yurkovskaya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
External Magnetic Field ◽  
Strong Coupling ◽  
Polarization Transfer ◽  
Strong Coupling Regime ◽  
Low Field ◽  
Spin Interactions ◽  
Proton Decoupling

Abstract. Strong coupling of nuclear spins, which is achieved when their scalar coupling 2πJ is greater than or comparable to the difference Δω in their Larmor precession frequencies in an external magnetic field, gives rise to efficient coherent longitudinal polarization transfer. The strong coupling regime can be achieved when the external magnetic field is sufficiently low, as Δω is reduced proportional to the field strength. In the present work, however, we demonstrate that in heteronuclear spin systems these simple arguments may not hold, since heteronuclear spin–spin interactions alter the Δω value. The experimental method that we use is two-field nuclear magnetic resonance (NMR), exploiting sample shuttling between the high field, at which NMR spectra are acquired, and the low field, where strong couplings are expected and at which NMR pulses can be applied to affect the spin dynamics. By using this technique, we generate zero-quantum spin coherences by means of a nonadiabatic passage through a level anticrossing and study their evolution at the low field. Such zero-quantum coherences mediate the polarization transfer under strong coupling conditions. Experiments performed with a 13C-labeled amino acid clearly show that the coherent polarization transfer at the low field is pronounced in the 13C spin subsystem under proton decoupling. However, in the absence of proton decoupling, polarization transfer by coherent processes is dramatically reduced, demonstrating that heteronuclear spin–spin interactions suppress the strong coupling regime, even when the external field is low. A theoretical model is presented, which can model the reported experimental results.

Nuclear magnetic resonance microscopy

1989 ◽  
Vol 47 ◽  
pp. 828-829
Author(s):  
Paul C. Lauterbur
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
Signal To Noise ◽  
Field Gradients ◽  
Useful Signal ◽  
Magnetic Field Gradients ◽  
Observation Times ◽  
Nuclear Magnetic

Nuclear magnetic resonance imaging can reach microscopic resolution, as was noted many years ago, but the first serious attempt to explore the limits of the possibilities was made by Hedges. Resolution is ultimately limited under most circumstances by the signal-to-noise ratio, which is greater for small radio receiver coils, high magnetic fields and long observation times. The strongest signals in biological applications are obtained from water protons; for the usual magnetic fields used in NMR experiments (2-14 tesla), receiver coils of one to several millimeters in diameter, and observation times of a number of minutes, the volume resolution will be limited to a few hundred or thousand cubic micrometers. The proportions of voxels may be freely chosen within wide limits by varying the details of the imaging procedure. For isotropic resolution, therefore, objects of the order of (10μm) may be distinguished.Because the spatial coordinates are encoded by magnetic field gradients, the NMR resonance frequency differences, which determine the potential spatial resolution, may be made very large. As noted above, however, the corresponding volumes may become too small to give useful signal-to-noise ratios. In the presence of magnetic field gradients there will also be a loss of signal strength and resolution because molecular diffusion causes the coherence of the NMR signal to decay more rapidly than it otherwise would. This phenomenon is especially important in microscopic imaging.

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