Journal of magnetic resonance最新文献

{"title":"Accurate reconstruction of 4D spectral–spatial images from sparse-view data in continuous-wave EPRI","authors":"Zheng Zhang ,&nbsp;Boris Epel ,&nbsp;Buxin Chen ,&nbsp;Dan Xia ,&nbsp;Emil Y. Sidky ,&nbsp;Howard Halpern ,&nbsp;Xiaochuan Pan","doi":"10.1016/j.jmr.2024.107654","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107654","url":null,"abstract":"<div><p>In continuous-wave electron paramagnetic resonance imaging (CW EPRI), data are collected generally at densely sampled views sufficient for achieving accurate reconstruction of a four dimensional spectral–spatial (4DSS) image by use of the conventional filtered-backprojection (FBP) algorithm. It is desirable to minimize the scan time by collection of data only at sparsely sampled views, referred to as sparse-view data. Interest thus remains in investigation of algorithms for accurate reconstruction of 4DSS images from sparse-view data collected for potentially enabling fast data acquisition in CW EPRI. In this study, we investigate and demonstrate optimization-based algorithms for accurate reconstruction of 4DSS images from sparse-view data. Numerical studies using simulated and real sparse-view data acquired in CW EPRI are conducted that reveal, in terms of image visualization and physical-parameter estimation, the potential of the algorithms developed for yielding accurate 4DSS images from sparse-view data in CW EPRI. The algorithms developed may be exploited for enabling sparse-view scans with minimized scan time in CW EPRI for yielding 4DSS images of quality comparable to, or better than, that of the FBP reconstruction from data collected at densely sampled views.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"361 ","pages":"Article 107654"},"PeriodicalIF":2.2,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140138570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fast spin echo MRI of reservoir core plugs with a variable field magnet","authors":"Rheya Rajeev ,&nbsp;Andrés Ramírez Aguilera ,&nbsp;Florea Marica ,&nbsp;Laura Romero-Zerón ,&nbsp;Bruce J. Balcom","doi":"10.1016/j.jmr.2024.107637","DOIUrl":"10.1016/j.jmr.2024.107637","url":null,"abstract":"<div><p>Fast Spin Echo MRI is now widely employed in biomedicine for proton density and <em>T</em>₂ contrast imaging. Fast Spin Echo methods provide rapid data acquisition by employing multiple echoes to determine multiple k-space lines with single excitations. Due to the multi-exponential behavior of <em>T</em>₂ in typical porous media, and the strong dependence of <em>T</em>₂ on the details of the experiment, acquiring a proton density image with Fast Spin Echo methods requires favorable sample and acquisition parameters. In recent years, we have shown the value of pure phase encode Free Induction Decay based methods such as SPRITE. However, in a reservoir rock, a typical <em>T</em>₂* is hundreds of µs, whereas a typical <em>T</em>₂ is hundreds of ms. Hence, there is merit in considering spin echo-based MRI measurements such as the Fast Spin Echo for rock core plug studies.</p><p>A variable field superconducting magnet was employed in this study. This is a new class of magnet for MR/MRI. These magnets have the flexibility of operation in the field range of 0.01 Tesla to 3 Tesla. This is advantageous when working with rock core plugs, as it allows one to maximize sample magnetization, by increasing the static field while controlling magnetic susceptibility mismatch effects, and thereby <em>T</em>_<em>2</em> and <em>T</em>_<em>2</em><em>*</em>, through reducing the static field. The magnetic fields employed in the study were 0.79, 1.5, and 3 Tesla.</p><p>Measurements were undertaken on five brine-saturated reservoir rock core plugs (Bentheimer, Berea, Buff Berea, Nugget, and Wallace). The results show that Fast Spin Echo measurements are more sensitive than SPRITE methods in amenable samples and usually feature higher resolution. Quantification of saturation with Fast Spin Echo methods requires correction for <em>T</em>₂ attenuation. The results also show that 3 Tesla is too high a static field in general for rock core MRI studies with either method. While the current study is focused on five representative reservoir rock cores, the conclusions which result are general for MRI of fluids in porous media.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"360 ","pages":"Article 107637"},"PeriodicalIF":2.2,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139819275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral diffusion of electron spin polarization in glasses doped with radicals for DNP","authors":"W.Th. Wenckebach","doi":"10.1016/j.jmr.2024.107651","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107651","url":null,"abstract":"<div><p>Spectral diffusion of electron spin polarization plays a key part in dynamic nuclear polarization (DNP). It determines the distribution of polarization across the electron spin resonance (ESR) line and consequently the polarization that is available for transfer to the nuclear spins. Various authors have studied it experimentally by means of electron–electron double resonance (ELDOR) and proposed and used macroscopic models to interpret these experiments. However, microscopic models predicting the rate of spectral diffusion are scarce. The present article is an attempt to fill this gap. It derives a spectral diffusion equation from first principles and uses Monte Carlo simulations to determine the parameters in this equation.</p><p>The derivation given here builds on an observation made in a previous article on nuclear dipolar relaxation: spectral diffusion is also spatial diffusion and the random distribution of spins in space limits the former. This can be modelled assuming that rapid flip-flop transitions between a spin and its nearest neighbour do not contribute to diffusion of polarization across the ESR spectrum. The present article presents predictions of the spectral diffusion constant and shows that this limitation may lower the spectral diffusion constant by several orders of magnitude. As a check the constant is determined from first principles for a sample containing 40 mM TEMPOL. Including the limitation then results in a value that is close to that obtained from an analysis of previously reported ELDOR experiments.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"360 ","pages":"Article 107651"},"PeriodicalIF":2.2,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140014641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Directional TV algorithm for fast EPR imaging","authors":"Chenyun Fang ,&nbsp;Yarui Xi ,&nbsp;Boris Epel ,&nbsp;Howard Halpern ,&nbsp;Zhiwei Qiao","doi":"10.1016/j.jmr.2024.107652","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107652","url":null,"abstract":"<div><p>Precise radiation guided by oxygen images has demonstrated superiority over the traditional radiation methods. Electron paramagnetic resonance (EPR) imaging has proven to be the most advanced oxygen imaging modality. However, the main drawback of EPR imaging is the long scan time. For each projection, we usually need to collect the projection many times and then average them to achieve high signal-to-noise ratio (SNR). One approach to fast scan is to reduce the repeating time for each projection. While the projections would be noisy and thus the traditional commonly-use filtered backprojection (FBP) algorithm would not be capable of accurately reconstructing images. Optimization-based iterative algorithms may accurately reconstruct images from noisy projections for they may incorporate prior information into optimization models. Based on the total variation (TV) algorithms for EPR imaging, in this work, we propose a directional TV (DTV) algorithm to further improve the reconstruction accuracy. We construct the DTV constrained, data divergence minimization (DTVcDM) model, derive its Chambolle–Pock (CP) solving algorithm, validate the correctness of the whole algorithm, and perform evaluations via simulated and real data. The experimental results show that the DTV algorithm outperforms the existing TV and FBP algorithms in fast EPR imaging. Compared to the standard FBP algorithm, the proposed algorithm may achieve 10 times of acceleration.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"361 ","pages":"Article 107652"},"PeriodicalIF":2.2,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140062850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A simple 1H (12C/13C) filtered experiment to quantify and trace isotope enrichment in complex environmental and biological samples","authors":"Katrina Steiner ,&nbsp;Wolfgang Bermel ,&nbsp;Ronald Soong ,&nbsp;Daniel H. Lysak ,&nbsp;Amy Jenne ,&nbsp;Katelyn Downey ,&nbsp;William W. Wolff ,&nbsp;Peter M. Costa ,&nbsp;Kiera Ronda ,&nbsp;Vincent Moxley-Paquette ,&nbsp;Jacob Pellizzari ,&nbsp;Andre J. Simpson","doi":"10.1016/j.jmr.2024.107653","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107653","url":null,"abstract":"<div><p>Nuclear magnetic resonance (NMR) based ¹³C tracing has broad applications across medical and environmental research. As many biological and environmental samples are heterogeneous, they experience considerable spectral overlap and relatively low signal. Here a 1D ¹H–¹²C/¹³C is introduced that uses “in-phase/opposite-phase” encoding to simultaneously detect and discriminate both protons attached to ¹²C and ¹³C at full ¹H sensitivity in every scan. Unlike traditional approaches that focus on the ¹²C/¹³C satellite ratios in a ¹H spectrum, this approach creates separate sub-spectra for the ¹²C and ¹³C bound protons. These spectra can be used for both quantitative and qualitative analysis of complex samples with significant spectral overlap. Due to the presence of the ¹³C dipole, faster relaxation of the ¹H–¹³C pairs results in slight underestimation compared to the ¹H–¹²C pairs. However, this is easily compensated for, by collecting an additional reference spectrum, from which the absolute percentage of ¹³C can be calculated by difference. When combined with the result, ¹²C and ¹³C percent enrichment in both ¹H–¹²C and ¹H–¹³C fractions are obtained. As the approach uses isotope filtered ¹H NMR for detection, it retains nearly the same sensitivity as a standard ¹H spectrum. Here, a proof-of-concept is performed using simple mixtures of ¹²C and ¹³C glucose, followed by suspended algal cells with varying ¹²C /¹³C ratios representing a complex mixture. The results consistently return ¹²C/¹³C ratios that deviate less than 1 % on average from the expected. Finally, the sequence was used to monitor and quantify ¹³C% enrichment in <em>Daphnia magna</em> neonates which were fed a ¹³C diet over 1 week. The approach helped reveal how the organisms utilized the ¹²C lipids they are born with vs. the ¹³C lipids they assimilate from their diet during growth. Given the experiments simplicity, versatility, and sensitivity, we anticipate it should find broad application in a wide range of tracer studies, such as fluxomics, with applications spanning various disciplines.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"361 ","pages":"Article 107653"},"PeriodicalIF":2.2,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1090780724000375/pdfft?md5=136568fdc7e8212556005d4d32e40998&pid=1-s2.0-S1090780724000375-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140104054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperpolarized long-lived spin state of methylene protons of 2-bromoethanol obtained from ethylene with non-equilibrium nuclear spin order","authors":"Simon V. Babenko ,&nbsp;Sergey V. Sviyazov ,&nbsp;Dudari B. Burueva ,&nbsp;Igor V. Koptyug","doi":"10.1016/j.jmr.2024.107648","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107648","url":null,"abstract":"<div><p>In this work we achieve a significant overpopulation (P_LLS≈1%) of the long-lived spin state (LLS) of methylene protons in 2-bromoethan(²H)ol (BrEtOD) obtained in a reaction between ethylene with non-equilibrium nuclear spin order and bromine water. Given all protons in ethylene are magnetically equivalent, its nuclear states are classified into nuclear spin isomers (NSIM) with total spin I = 2,1,0. Addition of parahydrogen to acetylene produces ethylene with a population of only those NSIMs with I = 1,0. As a result of the reaction with bromine water the non-equilibrium spin order of ethylene is partly transferred to the singlet LLS involving the two methylene groups of BrEtOD. The ¹H NMR signal enhancement (SE≈200) obtained as a result of the LLS readout is approximately equal to the SE of the hyperpolarized BrEtOD obtained with a single π/4 pulse. The LLS relaxation time (T_LLS) was shown to be approximately 40 s (≈8T₁) in the argon-bubbled sample.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"360 ","pages":"Article 107648"},"PeriodicalIF":2.2,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139936185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A detunable wireless resonator insert for high-resolution TMJ MRI at 1.5 T","authors":"Haoqin Zhu ,&nbsp;Qiang Zhang ,&nbsp;Rangsong Li ,&nbsp;Yuanyuan Chen ,&nbsp;Gong Zhang ,&nbsp;Ruilin Wang ,&nbsp;Ming Lu ,&nbsp;Xinqiang Yan","doi":"10.1016/j.jmr.2024.107650","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107650","url":null,"abstract":"<div><p>MRI is essential for evaluating and diagnosing various conditions affecting the temporomandibular joint (TMJ) and surrounding structures, as it provides highly detailed images that enable healthcare professionals to assess the joints and surroundings in great detail. While commercial MRI scanners typically come equipped with basic receive coils, such as the head receive array, RF coils tailored for specialized applications like TMJ MRI must be obtained separately. Consequently, TMJ MRI scans are often conducted using the head receive array, yet this configuration proves suboptimal due to the lack of specialized coils. In this study, we introduce a simple, low-cost, and easy-to-reproduce wireless resonator insert to enhance the quality of TMJ MRI at 1.5 T. The wireless resonator shows a significant improvement in signal-to-noise ratio (SNR) and noticeably better imaging quality than the head array alone configuration in both phantom and in vivo images.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"360 ","pages":"Article 107650"},"PeriodicalIF":2.2,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139985742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-efficiency low-power 13C-15N cross polarization in MAS NMR","authors":"Gal Porat-Dahlerbruch ,&nbsp;Jochem Struppe ,&nbsp;Tatyana Polenova","doi":"10.1016/j.jmr.2024.107649","DOIUrl":"10.1016/j.jmr.2024.107649","url":null,"abstract":"<div><p>Biomolecular solid-state magic angle spinning (MAS) NMR spectroscopy frequently relies on selective ¹³C-¹⁵N magnetization transfers, for various kinds of correlation experiments. Introduced in 1998, spectrally induced filtering in combination with cross polarization (SPECIFIC-CP) is a selective heteronuclear magnetization transfer experiment widely used for biological applications. At MAS frequencies below 20 kHz, commonly used for ¹³C-detected MAS NMR experiments, SPECIFIC-CP transfer between amide ¹⁵N and ¹³C^α atoms (NCA) is typically performed with radiofrequency (rf) fields set higher than the MAS frequency for both ¹³C and ¹⁵N channels, and high-power ¹H decoupling rf field is simultaneously applied. Here, we experimentally explore a broad range of NCA zero-quantum (ZQ) SPECIFIC-CP matching conditions at the MAS frequency of 14 kHz and compare the best high- and low-power matching conditions with respect to selectivity, robustness, and sensitivity at lower ¹H decoupling rf fields. We show that low-power NCA SPECIFIC-CP matching condition gives rise to 20% sensitivity enhancement compared to high-power conditions, in 2D NCA spectra of microcrystalline assemblies of HIV-1 CA_CTD-SP1 protein with inositol hexakis-phosphate (IP6).</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"361 ","pages":"Article 107649"},"PeriodicalIF":2.2,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139966542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation of transmission wave with low AM noise for sub-GHz CW-EPR spectrometer","authors":"Hideo Sato-Akaba ,&nbsp;Tsukasa Sakai ,&nbsp;Hiroshi Hirata","doi":"10.1016/j.jmr.2024.107633","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107633","url":null,"abstract":"<div><p>This study describes a technique to clean amplitude modulation (AM) noise of RF transmission waves, which is used to observe the sub-GHz CW-EPR spectrum. An RF transmitter amplifier that has the function of cleaning AM noise has been developed. Cleaning of the AM noise was owing to saturation of the output at the amplifier. Three stages of the amplifiers in series could effectively suppress the AM noise to about –176 dBc/Hz and –183 dBc/Hz at offset frequency of 10 kHz and 100 kHz, respectively at the carrier frequency of 750 MHz and the output power of 29 dBm. Since phase modulation (PM) noise is suppressed by phase sensitive detection, the AM noise in the transmission is dominant cause of the noise in the sub-GHz CW-EPR absorption spectrum using a reflection bridge, which depends on the quality factor of the resonator and the power of the RF transmission. The additive phase modulation (PM) noise of this amplifier was –171 dBc/Hz at an offset frequency of 100 kHz, which indicated that the frequency modulation (FM) of the transmission wave was not distorted with this amplifier. Therefore, conventional CW-EPR spectrometers that typically require FM for automatic frequency control or automatic tunning control can use this technique to increase sensitivity.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"360 ","pages":"Article 107633"},"PeriodicalIF":2.2,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139936187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic field dependence of the para-ortho conversion rate of molecular hydrogen in SABRE experiments","authors":"Alexander V. Snadin ,&nbsp;Natalia O. Chuklina ,&nbsp;Alexey S. Kiryutin ,&nbsp;Nikita N. Lukzen ,&nbsp;Alexandra V. Yurkovskaya","doi":"10.1016/j.jmr.2024.107630","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107630","url":null,"abstract":"<div><p>The use of parahydrogen – the isomer of molecular hydrogen with zero nuclear spin – is important for promising and actively developing methods for spin hyperpolarization of nuclei called parahydrogen induced polarization (PHIP). However, the dissolved parahydrogen in PHIP experiments quickly loses its spin order, resulting in the formation of orthohydrogen and reduction of the overall nuclear polarization of the substrate. This process is due to the difference of chemical shifts of hydride protons, as well as spin–spin couplings between nuclei, in the intermediate catalytic complexes, and it has not been rigorously explained so far. We proposed a new experimental technique based on magnetic field cycling for measuring the rate of molecular hydrogen para–ortho conversion in solution and applied it for non-hydrogenative PHIP Signal Amplification By Reversible Exchange (SABRE) experiments. The para–ortho conversion rate was measured over a wide range of magnetic field from 0.5 mT to 9.4 T. It was found that the conversion rate strongly depends on the magnetic field in which the reaction occurs, as well as on the concentrations of reactants. The rate decreases with increasing the concentration of pyridine ligand and increases with increasing the concentration of iridium catalyst. The model, which takes into account the reversible exchange of molecular hydrogen with the catalyst, nuclear spin–spin interaction of hydride protons with nuclei of ligands within catalytic complex and nuclear Zeeman interactions, qualitatively describes the experimental data. Two types of complexes with different spin system symmetry contribute to the molecular hydrogen conversion. In asymmetric complexes possessing hydride protons with different chemical shifts due to the presence of chlorine anion ligand the para–ortho conversion rate increases with magnetic field, while for symmetric complexes this mechanism is not operable. In the magnetic field where level anti-crossing occurs the resonant feature for the rate of para–ortho conversion is found. The results of this work can be utilized for finding the optimal conditions for obtaining the maximum hyperpolarization in the experiments employing parahydrogen.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"360 ","pages":"Article 107630"},"PeriodicalIF":2.2,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139744305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}