共查询到17条相似文献,搜索用时 109 毫秒
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建议了一种E.COSY型的13C-1H相关实验.在相应的13C-1H相关谱中,31P核对13C,1H核的被动偶合给出E.COSY型的谱峰裂分,可用于准确测定含磷化合物中的31P-1H和31P-13C偶合常数及其相对符号.测定了果糖-1,6-二磷酸根离子的31P-1H和31P-13C偶合常数。 相似文献
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本文将自旋回波技术用于识别直接与31P核偶合(31P-1H)和远程偶合(31P-O-C-1H)的氢类型。例举了二烷基二硫代磷酸、二烷基磷酸酯及其他几种产物中自旋回波方法归属的结果。 相似文献
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核磁共振研究大叶蛇葡萄提取物蛇葡萄素 总被引:3,自引:0,他引:3
通过质子检测的13C-1H异核多键化学位移相关谱、13C-1H异核多量子化学位移相关谱和质子相敏交换谱等NMR二维方法确定了传统中草药大叶蛇葡萄提取物的结构为蛇葡萄素(3,3',4',5,5',7-六羟基双氢黄酮醇),得到了更加准确的1H和13C化学位移归属,并观测和讨论了这一体系中溶剂二甲亚砜的质子化现象. 相似文献
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一种脑代谢研究的有效方法——高分辨率磁共振波谱分析 总被引:2,自引:0,他引:2
介绍了一种脑代谢研究的有效方法.成年大鼠脑经漏斗法液氮冷冻,制备脑组织高氯酸提取物并冷冻干燥,所得固体溶于D2O后用1H和31P磁共振波谱(MRS)检测.结果表明:脑高氯酸提取物的磁共振波谱有着极好的分辨率,31P MRS可以分辨出ATP、ADP、磷酸肌酸(PCr)、无机磷以及多种磷酯和糖磷;1H MRS可以分辨出乳酸(Lac)、N-乙酰天冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)、GABA、肌醇(Ino)、琥珀酸(Suc)以及多种氨基酸.各波峰积分后得到各种物质的相对含量,而这些代谢中间产物的相对含量变化可以反应脑内的代谢状况和脑受损伤情况. 相似文献
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Renata Longo Adelma Giorgini Silvia Magnaldi Lorenzo Pascazio Claudio Ricci 《Magnetic resonance imaging》1993,11(8):1209-1215
Two patients affected by severe Alzheimer's disease (AD) were investigated by MRI and image-guided 31P MRS. In one case, 1H MRS was additionally performed. In both cases the diagnosis of AD was confirmed, post mortem, by the pathologist. The spectral parameters of the 31P MR spectra were estimated by fitting the 31P MR signals in the time domain. Our 31P MRS results suggest that it is possible to detect the membrane catabolism, as indexed with the level of PDE resonances visible in in vivo 31P MRS, at least in severe AD cases. The 1H spectrum from AD brain showed a marked decrease of NAA signal respect to choline. 相似文献
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Laurent Delevoye Christian Fernandez Cludia M. Morais Jean-Paul Amoureux Valrie Montouillout Joo Rocha 《Solid state nuclear magnetic resonance》2002,22(4):306-512
27Al decoupling has been used to remove residual J-coupling interactions between31 P and 27Al in microporous aluminophosphates AlPO4-14 and AlPO4-40. In combination with 1H high-power decoupling, 27Al adapted decoupling yields 31P spectra with optimal sensitivity and resolution. The importance of double-resonance decoupling is further demonstrated by incorporating this technique in the MQHETCOR sequence. Unambiguous assignment of all the AlPO4-14 nuclear magnetic resonances is achieved by combining multiple-quantum evolution in the 27Al dimension and double-resonance decoupling in the 31P acquisition domain. 相似文献
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Shukla-Dave A Degaonkar M Roy R Murthy PK Murthy PS Raghunathan P Chatterjee RK 《Magnetic resonance imaging》1999,17(10):1437-1509
Metabolite mapping of human filarial parasite, Brugia malayi was carried out in vitro as well as in situ in host Mastomys coucha by 31P nuclear magnetic resonance (NMR) spectroscopy. Detection of parasites by visualizing contrast spots due to pathologic changes was observed by 1H magnetic resonance imaging (MRI). Major metabolites of adult B. malayi observed by 31P-NMR spectroscopy were of sugar phosphates (SP), phosphomonoesters (PME), glycerophosphoryl-ethanolamine (GPE), -choline (GPC), phosphoenolpyruvate (PEP), inorganic phosphate (Pi), nucleoside diphosphosugar and nucleotides-mono, -di and -tri phosphates. PEP and GPC were present in high concentration; PEP being the major energy reservoir and GPC the major phospholipid in this species of filaria. The 31P NMR spectra of testis of mastomys, showed seven major peaks of SP, PME, phosphocreatine (PCr), phosphodiesters (PDE), Pi, and nucleotides di- and tri-phosphates. The 31P-NMR spectra of testis of B. malayi infected animal also consisted of seven major peaks with significant decrease in the SP and PME peak showing changes in the carbohydrate and lipid metabolism of filaria infected testis. Thus, in vivo 31P MRS provided a non-invasive assessment of tissue bioenergetics and phospholipid metabolism. 相似文献
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The primary goal of this study was to establish a rigorous approach for determining and comparing the NMR detection sensitivity of in vivo 31P MRS at different field strengths (B0). This was done by calculating the signal-to-noise ratio (SNR) achieved within a unit sampling time at a given field strength. In vivo 31P spectra of human occipital lobe were acquired at 4 and 7 T under similar experimental conditions. They were used to measure the improvement of the human brain 31P MRS when the field strength increases from 4 to 7 T. The relaxation times and line widths of the phosphocreatine (PCr) resonance peak and the RF coil quality factors (Q) were also measured at these two field strengths. Their relative contributions to SNR at a given field strength were analyzed and discussed. The results show that in vivo 31P sensitivity was significantly improved at 7 T as compared with 4 T. Moreover, the line-width of the PCr resonance peak showed less than a linear increase with increased B0, which leads to a significant improvement in 31P spectral resolution. These findings indicate the advantage of high-field strength to improve in vivo 31P MRS quality in both sensitivity and spectral resolution. This advantage should improve the reliability and applicability of in vivo 31P MRS in studying high-energy phosphate metabolism, phospholipid metabolism and cerebral biogenetics in the human at both normal and diseased states noninvasively. Finally, the approach used in this study for calculating in vivo 31P MRS sensitivity provides a general tool in estimating the relative NMR detection sensitivity for any nuclear spin at a given field strength. 相似文献
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Agnieszka Kaflak Dariusz Chmielewski Andrzej Górecki Waclaw Kolodziejski 《Solid state nuclear magnetic resonance》1998,10(4):191-195
Bloch-decay and cross-polarization (CP) 31P nuclear magnetic resonance (NMR) spectra of healthy human trabecular bone were acquired under magic-angle spinning (MAS) at 3 kHz. A single peak at 3.1 ppm was detected. Variable-contact time 1H → 31P CP experiments revealed three signal components growing at various rates. The fast, moderate and slow components were assigned and assessed in P atom % to proton-rich (24%), hydroxyapatite (58%) and proton-deficient (18%) phosphate domains, respectively. Examination of CP kinetics is useful for the chemical characterization of bone tissue. 相似文献
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The relaxation time T1 values and nuclear Overhauser enhancement factor for 31P signal were determined in model solutions of metabolites ATP, PCr and Pi, and AMP at two frequencies and in H2O and 2H2O solutions. The data were analyzed to resolve the contribution of different relaxation mechanisms. A knowledge of NOE is important in the light of recent applications of double resonance methods to enhance the sensitivity of in vivo 31P spectroscopy. The results show that chemical shift anisotropy is the dominant mechanism for 31P in ATP at the high field, whereas the dipolar interaction mechanism is the main feature for the 31P relaxation of PCr and Pi. The dipolar mechanism responsible for NOE originates from interactions of solvent water with 31P moiety. Implications for in vivo spectroscopy are indicated. 相似文献