舒肝宁注射液的^(1)H-NMR指纹图谱分析

目的对舒肝宁注射液的^(1)H-NMR指纹图谱进行分析,为其质量控制标准技术升级提供参考依据。方法使用Noesygppr1d脉冲序列[recycle delay(RD)-90°-t 1-90°-t_(m)-90°-ACQ]采集1H-NMR谱图,质子共振频率为600.13 MHz,实验温度为298 K,通过方法学考察验证分析方法可靠性,采用相关系数法和夹角余弦法评价不同批次舒肝宁注射液样品的相似度。结果对舒肝宁注射液的^(1)H-NMR指纹图谱进行分析,共鉴定出88种化学成分,且不同批次的舒肝宁注射液具有较高的相似度。结论建立了一种基于^(1)H-NMR的舒肝宁注射液质量控制方法,可为舒肝宁注射液技术升级提供参考依据。

Laplace NMR谱图重建——从经典正则化到深度学习

拉普拉斯核磁共振(Laplace NMR)可以提供待测样品的扩散系数或弛豫时间等物理参数信息,是用于研究分子化学结构、动力学和相互作用的强大工具.Laplace NMR的适用性很大程度上取决于拉普拉斯逆变换相关的信号处理算法的性能.在本文中,我们首先讨论了Laplace NMR谱图重建问题的不适定性,接着回顾了经典的基于正则化约束的重建算法,并介绍了目前前沿的深度学习算法在处理Laplace反演问题方面的应用,最后总结了这些算法的优缺点,并对Laplace NMR信号处理方法未来改进方向进行了展望.

Structure and ion transport properties of organic ionic compounds revealed by NMR

Organic ionic plastic crystals(OIPCs)are emerging as an important material family for solid-state electrolytes and many other applications.They have significant advantages over conventional electrolyte materials,such as high ionic conductivity,non-flammability,and plasticity.Various nuclear magnetic resonance(NMR)spectroscopy techniques including solid-state NMR,pulsed-field gradient(PFG)NMR,and magnetic resonance imaging(MRI)etc.,provide us a versatile toolkit to understand the fundamental level structures,molecular dynamics,and ionic interactions in these materials.This article reviews the commonly used NMR methods including solid-and solution-state NMR,PFG-NMR,dynamic nuclear polarization(DNP)and the application of these methods in revealing the microscopic level structures and ion-transport mechanisms in OIPC materials.

A study on the temperature sensitivity of NMR porosity in porous media based on the intensity of magnetization Dedicated to the special issue “Magnetic Resonance in Porous Media”

The measurement of nuclear magnetic resonance(NMR)porosity is affected by temperature.Without considering the impact of NMR logging tools,this phenomenon is mainly caused by variations in magnetization intensity of the measured system due to temperature fluctuations and difference between the temperature of the porous medium and calibration sample.In this study,the effect of temperature was explained based on the thermodynamic theory,and the rules of NMR porosity responses to temperature changes were identified through core physics experiments.In addition,a method for correcting the influence of temperature on NMR porosity measurement was proposed,and the possible factors that may affect its application were also discussed.

Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-TOF)-Mass Spectrometry and^(13)C-NMR-Identified New Compounds in Paraberlinia bifoliolata(Ekop-Beli)Bark Tannins

Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial sector.The discovery of new tannins is therefore necessary.The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance(13C NMR).The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined,as was the mechanical strength of the resin hardened with Acacia nilotica extracts.Yield by successive water extraction was 35%.MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin,previously unknown in this family of extracts.These are 3-hydroxyproline acid,N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic acid.The identification of the above molecules means that this tannin can be used for industrial applications,as a resin in the manufacture of particleboard and in the formulation of green corrosion inhibitors.This information is reinforced by 13C NMR spectrometry,which indicates the presence of several polyflavonoid units,confirming the condensed nature of the tannin.Thermomechanical analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity(MOE)value of 4840 MPa at 150℃,confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.

Experimental aspects of ^(14)N overtone RESPDOR solid-state NMR spectroscopy under MAS beyond 60 kHz

Nitrogen-14(^(14)N)overtone(OT)spectroscopy under fast magic angle spinning(MAS)conditions(>60 kHz)has emerged as a powerful technique for observing correlations and distances between ^(14)N and ^(1)H,owing to the absence of the first-order quadrupolar broadenings.In addition,^(14)N^(OT) allows selective manipulation of ^(14)N nuclei for each site.Despite extensive theoretical and experimental studies,the spin dynamics of ^(14)N^(OT) remains under debate.In this study,we conducted experimental investigations to assess the spin dynamics of ^(14)N^(OT) using the rotational-echo saturation-pulse double-resonance(RESPDOR)sequence,which monitors population transfer induced by a^(14)N^(OT) pulse.The ^(14)N^(OT) spin dynamics is well represented by a model of a two-energy-level system.Unlike spin-1/2,the maximum excitation efficiency of ^(14)N^(OT) coherences of powdered solids,denoted by p,depends on the radiofrequency field(rf-field)strength due to orientation dependence of effective nutation fields even when pulse lengths are optimized.It is also found that the p factor,contributing to the ^(14)N^(OT) spin dynamics,is nearly independent of the B0 field.Consequently,the filtering efficiency of RESPDOR experiments exhibits negligible dependence on B0 when the ^(14)N^(OT) pulse length is optimized.The study also identifies the optimal experimental conditions for ^(14)N^(OT)/^(1)H RESPDOR correlation experiments.

基于小型化原子磁力计的零场NMR波谱仪搭建与测试

常规高场NMR波谱仪依托超导技术,其体积大、维护成本高,且存在样本磁化率不均匀导致的谱线展宽现象,零场或近零场NMR技术则可实现有效互补.本文自主搭建了一套基于小型原子磁力计的可移动零场NMR波谱仪,采用以多功能采集卡(National Instruments PCIe-6353)为核心的集成控制系统,仪器主磁场强度小于1nT,可实现高分辨率的J-耦合谱采集.为实现对自旋体系的有效操控,利用样品绝热初态的单脉冲激发实现对三轴脉冲线圈的精确标定.在此基础上,使用改进的组合脉冲序列实现了在^(13)C-^(1)H异核体系下的单自旋选择性操控,验证了零场NMR波谱仪的有效性.

HdeA在细菌外膜囊泡环境下的原位NMR研究

HdeA是一种定位于细菌周质的分子伴侣,在维持蛋白质稳态中起着重要的作用.以往对HdeA的研究主要是在体外条件下进行,限制了人们对HdeA在天然环境下发挥作用机制的理解.细菌外膜囊泡是细菌自发分泌到胞外环境的外膜囊泡,其内容物与周质环境相似.本研究将HdeA富集到细菌外膜囊泡(OMVs)中,通过核磁共振波谱研究HdeA在OMVs中的构象变化.结果表明,HdeA在其原位环境中表现出酸依赖性的构象变化.在低pH条件下HdeA主要通过S15、W16、T17、S27、T32、E36、G54、T57、C66、Q71、F74及D83等残基启动其分子伴侣功能.此外本研究也为原位研究其它周质分子伴侣的功能提供了新方法.

B21C7与DB21C7分子构象溶剂效应NMR研究

通过^(1)H NMR核磁波谱学方法研究了芳香冠醚B21C7和DB21C7构象的溶剂效应。结果表明,CD_(3)CN分子与两种芳香冠醚的苯环取代基存在CH^(+)…N相互作用,CD_(3)OD与冠醚环存在OH^(+)…O相互作用。由于不同溶剂分子的作用引起苯环取代基与冠醚环的相对位置改变,冠醚环在苯环取代基的屏蔽区域和去屏蔽区域间变化,产生了相应化学位移差异。

BPC6/t-BAMBP协同萃取铯机理的NMR研究

采用^(1)HNMR和^(133)CsNMR研究了BPC6和t-BAMBP协同萃取Cs^(+)的机理。结果表明,在氘代氯仿中,BPC6与Cs^(+)可形成配合物,t-BAMBP与Cs^(+)不发生配位。在BPC6/t-BAMBP与Cs^(+)进行协同萃取时,Cs^(+)首先通过与BPC6进行配位进入油相,随后由BPC6·Cs^(+)配合物向相互作用更强的t-BAMBP·Cs^(+)进行转移,且随着t-BAMBP加入量的增加,t-BAMBP的配位数增加,形成更稳定的t-BAMBP·Cs^(+)配合物。

ASSURE-NMR-HSQC实验检测保健食品中西地那非类物质

本研究通过使用灵敏度增强的带梯度形状脉冲进行异核单量子相干(HSQC)实验检测保健食品中违法添加的西地那非类物质。待测样品以甲醇溶解超声辅助提取,减压浓缩后以氘代DMSO溶解上机测试;利用Assure-NMR软件将得到的未知样品异核单量子相干(Heteronculear Single Quantum Coherence)谱图与已知西地那非类物质谱图进行模拟匹配。本方法检出限可以达到200μg·kg-1,能快速有效的对保健食品中西地那非类物质的违法添加侦察识别。该方法简便快捷,可以为食品安全监管部门提供一种新颖便捷的那非类物质监管稽查参考办法。

基于NMR的粮仓多场耦合图形化探测系统研究

粮仓是一个复杂的生态系统,其内部生物、非生物以及环境的耦合关系复杂,且只能对温度等少数参数进行探测,粮仓生态近乎“黑箱”。为了便于研究粮仓复杂的耦合关系、核实其中的基本规律,研究提出了一种基于核磁共振(Nuclear Magnetic Resonance,NMR)的粮仓多场耦合图形化探测系统。该系统由核磁共振成像分析仪、粮仓模拟装置和数据采集处理系统三部分组成,可同时实现粮堆温度、湿度和水分三参数的真实精准探测,并能通过配套云图生成软件直观、形象地呈现粮堆温度场、湿度场和水分场分布云图。该系统首次将低场核磁共振成像技术应用于粮堆多场耦合作用研究领域,为探明粮仓生态复杂的耦合关系,进一步证实相关理论研究结论提供了一种新的技术手段。该系统的提出有助于深化行业正在致力发展的粮堆多场耦合及生物场理论。

^(1)H and ^(13)C NMR spectral assignments for low-concentration bile acids in biological samples

Bile acids are the main body of enterohepatic circulation in vivo.They have essential functions such as emulsifying fat,bacteriostasis and regulating multiple metabolic pathways as signal molecules.However,the assignments of NMR signals for some lowconcentration bile acids are still needed.This study combined 1D nuclear magnetic resonance(NMR)and 2D NMR techniques including 1He1H correlation spectroscopy(COSY),1He1H total correlation spectroscopy(TOCSY),1H J-resolved spectroscopy(J-Res),1He13C heteronuclear single quantum coherence spectroscopy(HSQC),and 1He13C heteronuclear multiple bond correlation spectroscopy(HMBC)to assign the 1H and 13C signals of six bile acids in aqueous solution at physiological pH(~7.4)and nine bile acids in methanol.These data are of importance to the NMR-based studies on lipid digestion,absorption,and metabolism.

Functional group resolved NMR relaxation of 3-carbon adsorbates in mesoporous alumina

NMR relaxation analysis provides a unique and non-invasive probe of fluid dynamics within porous materials,and may be applied to the interpretation of a wide variety of material and interfacial characteristics.Here,we report two-dimensional^(1)H T_(1)-T_(2)relaxation correlation measurements of a range of three-carbon adsorbates(1-propanol,2-propanol and propanoic acid)imbibed within the mesoporous metal oxide gamma-alumina.Our data,acquired across field strengths of 2 MHz,12.7 MHz and 43 MHz,clearly reveal two populations in each measurement,identified as the alkyl and hydroxyl moieties of each adsorbate.These results expand the range of materials in which such functional group resolved relaxation is known to occur,and demonstrate the clear persistence of such phenomena using a range of typical benchtop NMR systems employed to study fluid-saturated porous media.

Evaluation of Cinnamon by Solid-State NMR Employing Relaxometry

To evaluate the molecular dynamics and the molecular regions presented in the cinnamon types it was chosen to evaluate them without any treatment, and for that it was used low-field nuclear magnetic resonance (NMR) through the pulse sequence such as MSE-FID, an NMR sequence in the time domain, and from the longitudinal relaxation time (with a time constant T1), employing the inversion-recovery pulse sequence. The low-field NMR results indicate that the techniques chosen were a very good alternative to evaluate these types of samples food and their structural organization according to their constituents. The molecular mobility is different.

米菲司酮的~1HNMR及^（13）CNMR研究

米菲司酮的１ＨＮＭＲ及１３ＣＮＭＲ研究孔漫１）贺文义韩广甸王映红（中国医学科学院中国协和医科大学药物研究所，北京１０００５０）米菲司酮（Ｍｉｆｅｐｒｉｓｔｏｎｅ，ＲＵ４８６）１１β－〔４－（Ｎ，Ｎ－二甲氨基）苯基〕－１７α－（丙炔－１）－Δ４，９－雌...

四萜Methyl Sartortuoate的分离和NMR归属

从采自海南岛三亚的扭曲肉芝软珊瑚Sarcophytontortuosum中分离得到3个新四萜和1个已知四萜methylsar-tortuoate(1).利用HMQC,1H-1HCOSY,HMBC等二维NMR方法首次对methylsartortuoate(1)的所有1H,13CNMR信号进行了完全的归属.

三维NMR谱

３ＤＮＭＲ谱是２ＤＮＭＲ谱附加一个时间周期扩展而成。３ＤＮＭＲ共振峰的重叠降低，并且灵敏度与常规的２ＤＮＯＥＳＹ实验大体相当。采集３ＤＮＭＲ数据组所需时间太长，因此迄今为止，该方法的实际应用只局限于那些浓度相当高的样品，尽管目前还十分费时，但很可能３ＤＮＭＲ不久即可成为常规的ＮＭＲ技术。

Further discussion of CO_(2) huff-n-puff mechanisms in tight oil reservoirs based on NMR monitored fluids spatial distributions

Due to the poor physical properties of tight reservoirs,CO_(2) huff-n-puff(HNP)is considered a potential enhanced oil recovery(EOR)method after primary depletion.Optimization plays a critical role in the effective implementation of CO_(2) huff-n-puff.But the optimization requires a good understanding of the EOR mechanisms.In this work,the spatial distribution of oil saturation under different experimental conditions was analyzed by the NMR method to further discuss the HNP mechanisms.According to the variation of 1D frequency signal amplitude,we divided the core into the hardly movable area and movable area,the region with the obvious signal decline was defined as the movable area,and the hardly movable area was the region with limited signal decline.Based on that the recovery characteristics of different scenarios were evaluated.Firstly,the necessity of the soaking stage was studied,where three scenarios with different soaking times were carried out.Secondly,the injection pressure was adjusted to investigate the effect of the pressure gradient.The T_(2) spectra show that soaking has significantly improved the production of crude oil in small pores,and higher oil recovery in a single cycle is observed,but it is lower when the elapsed time(total operation time)is the same.31.03% of oil can be recovered after 3 cycles HNP,which increases to 33.8% and 37.06% for the 4 cycles and 6 cycles cases.As the pressure gradient increases,more oil is removed out of the matrix,and the oil in the deep part of the reservoir can be effectively recovered.During the CO_(2) huff-n-puff process,the oil distributions are similar to the solution gas drive,the residual oil is distributed at the close end of the core and the range that the oil can be efficiently recovered is limited.

~1H，^（13）CNMR光谱在木素化学研究中的应用

木素化学结构研究是木材化学的重要内容之一．一般化学研究方法很难完全搞清木素化学结构．核磁共振技术引入木素化学研究中以后，使木素化学结构研究变得简单易行，核磁共振技术现在已成为木素研究中重要手段之一．本文介绍了１ＨＮＭＲ谱，１３ＣＮＭＲ谱，二维（２Ｄ）ＮＭＲ谱以及固体１３ＣＮＭＲＣＰ／ＭＡＳ技术在木素化学研究中的应用和进展．