Solid-state nuclear magnetic resonance (NMR) of aligned samples has been rapidly -emerged as a successful and important spectroscopic approach for high-resolution structural characterization of membrane-bound proteins and peptides in their “native-like” hydrated lipid bilayers. Because the structures, dynamics, and functions of membrane-bound proteins and peptides are highly associated with heterogeneous native environments, proteins and peptides are prepared for solid-state NMR measurements in the presence of either bilayers that are mechanically aligned on glass plates or magnetically aligned bicelles. Orientation dependent anisotropic spin nuclear interactions from these aligned proteins and peptides can be obtained. These orientational restraints can be assembled into high-resolution threedimensional structures. Driven by significant advances in sample preparation protocols as well as NMR probes and other methodology developments in the past decade, the aligned sample NMR approach has been well developed and become an effective way for structural characterization of membrane-bound proteins and peptides. This review introduces high resolution solid-state NMR spectroscopy of aligned samples and summarizes recent methodology developments in this arena.

Chiral recognition of β-cyclodextrin (β-CD) to chiral drug D/L-10-camphoric sulfonic acid (CSA) was investigated using high resolution liquidstate NMR spectroscopy. It was found that CSA can enter the hydrophobic cavity of β-CD and interact with it chirally. The results of 2D ROESY experiments suggested that the enantiomers of CSA enter into the hydrophobic cavity of β-CD from its wide brim, not from its narrow brim. Stoichiometry result showed a 1∶1 complex between the host and the guest. It was demonstrated that β-CD can be used to discriminate the enantiomers of CSA.

¹H chemical shifts of sodium dodecyl sulfate (SDS) and Triton X-100 (TX-100) were measured in their mixed aqueous solutions with different molar ratios. The critical micelle concentrations (cmc^*₁, cmc^*₂) of the two surfacents and the critical mixed micelle concentrations (cmc^*) at different molar ratios were calculated by simulating the chemical shift data using a two-state exchange model.  The interaction parameters (β_M) and the composition of mixed micelles were evaluated. The mixed-micellization processes were discussed on the basis of the results obtained.

Quadrature receiver coils are often used in magnetic resonance imaging. However, the imbalance of the detection sensitivity between the Ichannel and the Q-channel in these coils can affect the overall signal to noise ratio (SNR) of the images obtained. In order to solve this imbalance problem, we propose a digital method for combining the signals from the two channels of the quadrature coils, in which the weighted coefficients of the I and Q channels are determined dynamically in the K-space. It was demonstrated that optimal SNR can be obtained with the present method.

Type-I diabetes was induced in rats by a single injection of streptozotocin (STZ). Directional diffusion-weighted imaging on the optic nerves were performed one month later to monitor the early optic neuropathy (e.g., axonal injury and myelin sheaths damage) induced by diabetes. Water diffusivities parallel and perpendicular to the axonal tracts were measured by apparent diffusion coefficients ADC_∥ and ADC_⊥, respectively. Compared to the control animals, the STZ-treated animals showed a trend of reduced ADC_⊥ in bilateral optic nerves, but less consistent changes in ADC_∥.

Oligomerization of Aβ peptides and fibril formation play critical roles in the pathology of Alzheimer’s disease (AD). Aβ_(1-42) is the most toxic species of the  Aβ peptides. Disruption of Aβ aggregation is a promising approach in developing therapeutics for AD. In our previous studies, some compounds were found to be able to bind to Aβ_(12-28). In this work, two-dimensional NMR methods were used to assign the ¹H and ¹⁵N chemical shifts of Aβ_(12-28) peptide. The results should provide a basis for the interaction study of Aβ_(12-28) peptide with small molecule inhibitors.

A software system used for the consoles of NMR spectrometers, designed -using a multi-layer architecture, is presented. The software system is divided into five layers: Linux driver layer, driver interface layer, BZ logic layer, socket layer and protocol control layer. Each layer has a specific function and is maintained independently. It was shown that multilayer architecture design not only reduces coupling in the system and simplifies the system structure, but also allows developing different layers simultaneously, thus improving the programming efficiency and reducing the development cycle time. The software system was debugged on the hardwares developed independently in the lab and passed rigorous testing.

Natural abundance N-phosphoryl amino acids were studied by  ¹⁵N NMR spectroscopy. ¹⁵N NMR chemical shifts and coupling constants were determined by ¹⁵N-¹H heteronuclear HSQC and HMBC techniques. The stereosensitive ¹J (¹⁵N-³¹P) and ¹J(¹⁵N-¹H) coupling constants were used to analyze the geometry of nitrogen atoms in these compounds. The structural and ¹⁵N NMR spectroscopic characteristics of N-phosphoryl amino acids were discussed.

Nuclear quadrupole qesonance (NQR) methods can be used to detect hidden explosive, with advantages such as high accuracy, low false alarm rate and non-radioactive contamination. However, the practical use of the NQR methods for explosive detection are limited by low signal-to-noise ratio. In this work, a signal process method for NQR signals is presented, which is based on wavelet transform and specially designed for the detection of pentaerythritol tetranitrate (PETN) with NQR. It was shown that this method can eliminate the interferences from external noises, and improve the accuracy of PETN detection.

Polymerizable 1, 8-naphthalimides derivatives, 4-dimethylamino-N-allyl-1, 8-naphthalic anhydride,  4 nitro-N-allyl-1, 8-naphthalic anhydride  and 4-nitro-N-[(3-trimethoxysilane)-propyl]-1, 8-naphthalic anhydride, all containing polymerizable carbon-carbon double bond or 3-trimethoxysilane groups, were synthesized from 4-bromine-1, 8-naphthalic anhydride and 4-nitro-1, 8-naphthalic anhydride. The structure of these compounds were determined by 1D (¹H and ¹³C NMR) and 2D NMR techniques, including ¹H-¹H COSY、HMBC and HSQC. The ¹H and ¹³C NMR chemical shifts of the compounds were assigned. The photo-physical properties of the compounds were studied by ultraviolet absorption spectroscopy and fluorescence emission spectroscopy. The substituent effects on the fluorescence intensities of the compounds were discussed.

The molecular structures of pentaerythritol diacetals with chiral axes were -elucidated- by 1D and 2D NMR techniques, including ¹H NMR, ¹³C NMR, DEPT, ¹H-¹H COSY, HSQC and HMBC. The chemical environment of the eight hydrogen atoms in the four methylenes were analyzed. The ¹H and ¹³C chemical shifts of 3, 3′-bis (2, 4-dichlorophenyl)-2, 4, 2′, 4′-tetraoxaspiro\[5.5\] undecane were assigned. The results should provide a basis for elucidating molecular structures of other pentaerythritol diacetals and diketals.

Single-scan ultrafast method can be used to obtain two-dimensional and multi-dimensional NMR spectra within a single scan via spatially encoding technique, thus greatly shortening the experimental time. It has found wide applications in the NMR field. In this review, the discrete spatially encoding single-scan ultrafast method was taken as an example to elucidate the underlying principles. Some novel single-scan methods such as continuous amplitude-modulated encoding and continuous phase-modulated encoding were discussed. The applications of the single-scan methods were introduced and their limitations were analyzed. The perspective of this technique was briefly discussed.

This review paper introduces 2D NMR pulse trains frequently used in petroleum logging and their applications, as well as relevant relaxation mechanisms. In NMR logging, often a set of data is acquired at different CPMG echo spacing in the presence of constant gradient magnetic field. Twodimensional mathematical inversion is then applied to solve the dataset, yielding two-imensional NMR map (D-T₂). In the meanwhile, 2D NMR technique can be used to measure the property parameters of formation fluid and the petrophysics parameters directly, such as diffusion coefficient, relaxation time, crude oil viscosity, oil saturation, free water saturation, porosity, permeability and so on. The 2D NMR map can also be used to differentiate oil, gas and water, determine internal gradient field in and judge wettability of the sample. 2D NMR techniques offer powerful tools for identifying fluid type in NMR logging.