Human insulinoma-associated protein 1 (INSM1) is a transcriptional regulator recognizing sequence-specific DNA through its C-terminal zinc finger (ZF) domains. INSM1 contains five zinc finger domains, whose structures are still not known; therefore, the mechanisms through which it recognizes DNA also remain unclear. In this study, we designed the recombinant plasmid pET-32m-INSM1(424-497), which can express the truncated INSM1 fragment containing the zinc finger domains 4 and 5[i.e., ZF(4-5)]. Expression and purification of ZF(4-5) were explored in order to achieve high protein yield for further structural and functional study. Nuclear magnetic resonance (NMR) and circular dichroism (CD) spectra revealed that chelation of Zn²⁺ to C2H2 in the ZF(4-5) was important for its structural stability, and also confirmed that the active-sites, Zn²⁺-chelated histidines, had the δ-tautomeric form.

Aromatic carbon mole ratios[C(ar)%] in model oil samples, which consisted of 11 saturated/unsaturated compounds with known contents, were determined by quantitative carbon nuclear magnetic resonance spectroscopy (¹³C qNMR) with the design for six Sigma (DFSS) methodology. An empirical model was established between C(ar)% and sample parameters, including sample concentration (Conc.), concentration of relaxation reagent Cr(acac)₃ and relaxation delay (D1). Based on the model, the optimal condition was determined to be at sample concentration 180 mg/mL, concentration of Cr(acac)₃ 12 mg/mL and D1 10.5 s. Eight verification experiments were performed under the optimal condition, and the results showed fairly good repeatability (RSD=0.61%) and accuracy (99.0%~100.6%). The work also gave some supplementary suggestions on parameter settings for the current GB method/ASTM method.

NMR spectroscopy was used to study the behaviors of three binary surfactant micellar solutions, NP-10/DTAC, NP-10/C₁₂-C₄-C₁₂ and NP-10/C₁₂-C₈-C₁₂ respectively. Relative arrangement and the sites of interactions between the surfactant molecule pairs in the mixed micelles, as well as the differences in inter-/intra- molecular interactions were investigated. 2D NOESY experiments revealed that the number of sites of interaction varied across the different binary mixtures, and the degree of interactions increased in the following order:NP-10/C₁₂-C₈-C₁₂ > NP-10/C₁₂-C₄-C₁₂ > NP-10/DTAC. Self-diffusion coefficient experiments showed that the influence of NP-10 on the hydro-dynamic radius of the mixed micelles was greater than that of quaternary ammonium salts. Spin-spin relaxation time experiments indicated that, for NP-10/DTAC and NP-10/C₁₂-C_s-C₁₂ (s=4 or 8) binary systems, intra-molecular interactions dominated and inter-molecular interactions began to decrease at molar ratios 1:3 and 1:2. These points corresponded to the optimal molar ratio for synergic effects. Spatial distance measurements supported this result, confirmed that the optimal molar ratio was 1:3 and 1:2.

With 1D NMR, 2D NMR and variable-temperature ¹H NMR, the ¹H and ¹³C NMR chemical shift of two isomers (E/trans and E/cis) of a new N-acylhydrazone derivative containing benzimidazole moiety (new compound 1), naming 2-[2-(4-methylphenoxymethyl)-1H-benzimidazol-1-yl]-N'-{[4-(dimetilamino)phenyl]methylene}acetohydrazide, were assigned. Coupling constants and tautomeric ratios of the isomers were determined. Experimental results showed that compound 1 in DMSO-d₆ had both E/trans and E/cis isomers, and the ratio of the dominant E/cis isomer was 74.2%.

Ultraviolet (UV) spectrum, infrared (IR) spectrum, mass (MS) spectra and nuclear magnetic resonance (NMR) spectra (i.e., ¹H NMR, ¹³C NMR, DEPT, ¹H-¹H COSY, NOE, ¹H-¹³C HSQC and ¹H-¹³C HMBC) of Triptophnolide were collected and interpreted. All ¹H and ¹³C NMR signals were assigned. Base on the data, the structure of reference standard Triptophnolide was determined.

Ultraviolet (UV) spectrum, infrared (IR) spectrum, electrospray ionization-mass spectra (ESI-MS) and nuclear magnetic resonance (NMR) spectra (i.e., ¹H NMR, ¹³C NMR, DEPT, ¹H-¹H COSY, ¹H-¹³C HSQC and ¹H-¹³C HMBC) of bortezomib were collected and interpreted. All ¹H and ¹³C NMR signals were assigned. The structure of the compound was preliminarily determined.

A 500 MHz NMR spectrometer was successfully built in-house in Wuhan Institute of Physics and Mathematics in 2006, and it had been used for researches in many areas. However, the performance of this spectrometer in acquiring two-dimensional (2D) NMR spectra needed for structure elucidation had not been evaluated until now. In this paper, we acquired all the one-dimensional (1D) and 2D (i.e., ¹H-¹H COSY, ¹H-¹H TOCSY, J-Res, ¹H-¹³C HMQC and ¹H-¹³C HMBC) NMR spectra of taxol on this spectrometer, and used these spectra to elucidate the structure of the compound. The results showed that, with the spectra acquired on the 500 MHz NMR spectrometer built in-house, the structure of taxol could be elucidated correctly. We also corrected some incorrect NMR assignments of taxol existing in the literature.

The synthesis of flame retardant 9,10-dihydro-9-oxa-10-phosphaphen-anthrene-10-oxide (DOPO) involves many steps of chemical reactions, including esterification, Friedel-Crafts acylation, hydrolysis and dehydration. We analyzed the composition of the products from each of the steps with ³¹P NMR. The results were used to deduce the reaction routes and to optimize the reaction conditions. Based on the results, some key factors that may influence the yield and purity of DOPO were determined.

A series of substituted diaryl nitrones XArCH=N(O)ArY were synthesized, and their ¹H NMR spectra were measured. The ¹H chemical shift of the CH=N(O) bridge groups, δ_H[CH=N(O)], in each compound was determined. The effects of substituents X and Y on δ_H[CH=N(O)] were investigated quantitatively. A four parameters correlation equation was constructed to model the changes of δ_H[CH=N(O)] with substituents, yielding a standard error of 0.020. The result indicated that δ_H[CH=N(O)] in substituted diaryl nitrones are mainly affected by four factors:field/inductive effect (S) of substituent X[σ_F(X)], conjugative effect of substituent Y[σ_R(X)], substituent specific cross-interaction effect between X and Y (Δσ²) and substituent specific crossinteraction effect between X and O^-[Δσ²_(X-O^-)]. Among these factors, the contribution of Δσ²_(X-O^-) to δ_H[CH=N(O)] was more than 70%. A comparison of δ_H[CH=N(O)] in substituted diaryl nitrones to δH(CH=N) of the CH=N bridge group in diaryl Schiff base XArCH=NArY revealed no good linear relationship between δ_H[CH=N(O)] and δH(CH=N). Therefore it should be noted that one cannot simply use the change of δH(CH=N) to deduce the change of δ_H[CH=N(O)] when carrying out organic molecule structure elucidation with NMR spectra.

NMR measurement of flowing fluid is a highly effective and non-destructive online detection method, which can be widely used in pipeline fluid delivery process, chemical reaction process, river flowing process and other time-shift processes. However, flow will induce incomplete polarization and incomplete signal acquisition, such that the effects of flow rate on NMR measurement cannot be ignored. In this work, we analyzed quantitatively how factors related to the flowing state affect NMR measurement. Correction methods were proposed to achieve accurate NMR flowing fluid measurements.

High homogeneity of the magnet field is an essential prerequisite for measuring weak signals and short spin-spin relaxation time on a nuclear magnetic resonance (NMR) analyzer. In this study, we designed active shimming coils, based on a target-field approach, for low filed NMR analyzers. Constant current source was designed according to the coil power supply. An active shimming platform used in a NMR analyzer's 0.45 T magnet system was constructed over a large target-diameter-sphere-volume (25.4 mm DSV) of interest. The basic structure and operation principles of the system, as well as the shimming method, were introduced. The feasibility and practicality of the design was demonstrated by experimental measurements.

A heterogeneous dual-core receiver system that combines advanced reduced instruction set computing (RISC) machines (ARM) and field programmable gate array (FPGA) is proposed for low-field nuclear magnetic resonance (NMR) applications. This system has advantages, such as high speed analog to digital converter (ADC) acquisition and variable gain control. In this design, the system generator, a system development tool from the Xilinx Company, can implement internal signal processing functions. Experimental results showed that, compared with the traditional receiver, the digital receiver had compact structure, strong reconstruction, high sampling rate and low cost. In addition, variable gain control enabled the digital receiver to achieve a large dynamic range such that the signal-to-noise ratio (SNR) of the reconstructed image could be improved.

Due to its non-destructive characteristic, nuclear magnetic resonance (NMR) spectroscopy was used to study the fiber saturation point (FSP) of Pseudotsuga menziesii before and after heat treatment. The bound water amount in saturated wood cell wall was determined by analysis of T² relaxation time distributions measured using GPMG (Carr-Purcell-Meiboom-Gill) sequence at -3℃ and 25℃. Results showed that the FSP of Pseudotsuga menziesii treated with various temperatures are 32.82% (180℃), 29.40% (200℃), 24.90% (220℃) and 38.76% (untreated), which indicate that FSP of Pseudotsuga menziesii decreases with increased heat treatment temperature. This study reflects that NMR could provide detailed information about wood water distribution rapidly and efficiently.

Bone, as a structural organization and an important hematopoietic organ of the human body, plays critical biological roles in protecting human organs, storing calcium and phosphorus, participating in metabolism regulation and providing attachment sites for muscles. Understanding the microstructure of bone is important for intervention and treatment of bone diseases. However, experimental characterizations of the bone has been hindered by the morphological diversity of the bone, coexistence of organic and inorganic components, and sensitivity of bone samples to physical and chemical treatment. Compared with other techniques, solid-state nuclear magnetic resonance (NMR) can study the bone in-situ without any chemical pretreatment, thus avoiding changing bone structure. In addition, most of the chemical elements in the bone are magnetic resonance detectable, such as ¹H, ¹³C, ³¹P, ¹⁹F, ⁴³Ca, ²⁹Si, ²⁵Mg and ⁸⁷Sr. Therefore, high resolution solid-state NMR technique provides a powerful tool for structural studies of the bone and bone biomaterials. In this paper, we reviewed the recent progresses in the application of solid-state NMR to bone and bone biomaterials studies.