Conformation of Gemini 16-4-16 in heavy water solutions at concentrations close to the critical micellar concentration (cmc) was studied by NMR relaxation, self-diffusion and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY). In forming micelles, the protons of the spacer group and a part of hydrophobic protons next to the polar head group are involved in the surface layer of the micellar core. The hydrophobic protons away from the polar head group are situated internal in the micellar core. The motion of the molecules are relatively more restricted than their monomeric homologue CTAB. 2D NOESY experiments show cross peaks between the protons in or close to the spacer group. The inter-proton distances thus calculated show deviation from those of the intra-molecular ones, calculated by HYPERCHEM. Therefore, inter-molecular interaction is responsible for these strong cross peaks. The corresponding proton pairs are in near vicinity. Accordingly we postulate a special arrangement of the molecules in the spherical 16-4-16 micelles.

The structure of tolperisone hydrochloride was elucidated by 1D and 2D NMR techniques (i.e., gCOSY, gNOESY, gHSQC and gHMBC). The ¹H and ¹³C chemical shifts of this compound were completely assigned, and its stereochemistry was investigated by NOESY.

The interactions between α-cyclodextrin and four ligands (salicylic acid, salicylate, phenol and benzoate) was studied by NMR diffusion measurements. The diffusion coefficients of the ligands in the solution, which reflects the affinity of association between α-cyclodextrin and them, were found to decrease as the concentration of α-cyclodextrin increased. Together with 2D-ROESY experiments, it was demonstrated that in forming inclusion complex, the hydrophobic interaction is predominant among various possible interactions between α-cyclodextrin and the ligands.

The structures of 1, 4∶3, 6-dianhydro-β-D- fructofuranosyl 4-chloro-4-deoxy-α-D-galactopyranoside( 1),  1, 4∶3, 6-dianhydro-β-D-fructofuranosyl 3, 6-anhydro-4-chloro-4-deoxy-α-D-galactopyranoside (2) and 1, 6-dichloro-1, 6-dideoxy-β-D-fructofuranosyl 3, 6-anhydro-4-chloro-4-deoxy-α-D-galactopyranoside (3) were elucidated using 1D and 2D NMR spectroscopy (¹H NMR,  ¹³C NMR,  DEPT-135,  ¹H-¹H COSY,  HSQC,  HMBC) and HRMS spectra. ¹H and ¹³C chemical shifts of these compounds were assigned.

A new diterpene，lasiodonin acetonide，was isolated from Chinese medicinal herb Rabdosia rubescens (Hems L.). Referring to the ¹H and ¹³C NMR spectra of lasiodonin，maoecrystal T，wikstroemioidin B and rabdocoetsin A，its structure was determined to be  1α，6β，7β，11β-tetrahydroxy-cyclic，1，11-(1-methyl- ethylidene acetal)-7，20-epoxy- Kaur-16-en-15-one by 1D (¹H，¹³C NMR and DEPT) and 2D (¹H-¹H COSY，HMQC and HMBC) NMR techniques.

A novel method based on atomic electronegativity interaction vector (AEIV) was developed to describe chemical environment and atomic state in amino acids, and to predict ¹³C chemical shifts. One hundred and three ¹³C chemical shifts for twenty natural amino acids were calculated by the method. The precision of calculation is cross-validated using the chemical shifts calculated by established methods, including molecular modeling, the leave-one-out (LOO) method and the leave-molecule-out (LMO) method. The correlation coefficients (R) obtained are R_MM=0.966, R_LOO=0.958 and R_LOO=0.950, respectively. The model developed was also applied to predict fifteen ¹³C NMR chemical shifts for two newly discovered natural amino acids.

This study measured ¹³C NMR chemical shifts of 348 carbon atoms in 64 alcoholic compounds, and studied their relationship with the atomic ionicity index, the polarizability effect index and the structural information parameters Nⁱ_H(i=α、β、γ) and γ_OH of the compounds. The results indicated that the ¹³C NMR chemical shifts of alcoholic compounds can be described by following equation: 
         δ_C=[-2.3-0.8577(INI)+10.623 3(∑PEI)+0.563 0(INI/∑PEI) -0.420 8(∑PEI/INI)

                +0.197 9 N^α_H-7.462 5 N^β_H+24.446 7N^γ_H+0.256 3 γ_OH]×（-53.169）

which provides a new method for calculating ¹³C NMR chemical shifts of alcoholic compounds.

This paper presents an equation: δ_cal=615.0+Δ_α for calculating ¹⁷O-NMR chemical shifts of carbonyls of aldehydes and derivatives of formic acid. Twenty-one substituent parameters for the equation were obtained by linear least square regression analysis. The validity of the equation was checked by 32 aldehydes and derivatives of formic acid. A confidence limit of 99.5% was obtained and the calculating errors for all compounds tested were less than 5.0 (relative errors 0.5%).

Receiver plays an extremely important role in a magnetic resonance imaging system as it's precision and stability directly determine the qualities of the images obtained. In this study, an all-digital receiving algorithm based on general floating point DSP was developed for low-field MRI systems, and shown to be highly precise and efficient. Amplified echo signal was first directly digitalized, and then sent to DSP where digital quadrature demodulation, filtering and decimation were carried out. Cascaded data filtering was done with filters with high computational efficiency including integrator-comb filter (CIC), half band filter (HB) and equiripple FIR filter. Single precision floating point format was used in the whole process so that high precision and large dynamic range were maintained. The algorithm developed was implemented with a DSP program in ANSI C and inline assembler. Simulation on CCS2.2 proved that it can be used for real time detection and meets the requirements for practical use.

Three compounds were isolated from the active fraction of Alisma orientalis (Sam.) Juze extract that inhibits urinary oxalate calcium calculi formation, and identified to be alisol F 24-acetate, alisol A 24-acetate and alismoxide. The proton chemical shifts of alisol F 24-acetate were assigned by using 2D NMR techniques including ¹H-¹H COSY、HMQC and HMBC.

Severe spectral overlap occurs in the NMR spectrum of thymopoietin because the composing amino acid residuals have similar chemical shifts. In this paper, the structure of thymopoietin was determined by modified DPFGSE 1D-TOCSY and 1D-NOESY NMR techniques, which was then confirmed by computer simulation. The results demonstrate that DPFGSE 1D-TOCSY and 1D-NOE are efficient tools for structural elucidation of thymopoietin.

The Atheron-Todd reaction has been used extensively for synthesis of phosphates and phosphoroamidates. In this study, we show that 4-aminoantipyrine can be phosphorylated by a modified Atheron-Todd procedure in which diisopropyl phosphite (DIPPH) and tetrachloromethane mixture was dropped into a solution mixture of 4-aminoantipyrine, trithylamine and dioxane. The reaction product NDIPP-4-antiprine was obtained with good yield, its structure was elucidated by NMR, ESI-MS and X-ray crystallography.

Increasing the magnitude of RF excitation field is a commonly used method to increase excitation bandwidth in low field pulsed NMR experiments. This paper presents a RF compensation method for increasing the RF excitation bandwidth according to the distribution of static magnetic field. The validity of the method is demonstrated with the target field method.

Gemini surfactant is a new type of surfactant, with molecules made up of two amphiphilic moieties covalently connected at the level of the head group by a spacer. Because of its unique structure, Gemini surfactant often has some special properties, such as high surface activities and special micro-configurations. The results of many previous studies indicate that the length and the structure of the spacer play the most important roles in determining the surface activities of Gemini surfactant. In comparison with other methods, NMR has some unique advantages for studying the micellization and self-aggregation behaviors of Gemini surfactant.