Membrane proteins are responsible for a wide range of essential physiological processes, and important drug targets for treating diseases. However, structural study on membrane proteins lags far behind that on soluble proteins, and this, in large part, is due to technical difficulties in preparing homogeneous, stable and structurally relevant samples in a membrane-like environment. Phospholipid bilayer Nanodisc is novel model membrane derived from highdensity lipoprotein particles, and has proven to be useful in structural studies on membrane proteins. It has been shown that Nanodisc can provide a “native-like” lipid bilayer environment for many membrane proteins, such as VDAC-1 (voltage-dependent anion channel), GPCRs (G-protein-coupled receptors) and cytochrome P450s, thus enabling structural studies on these membrane proteins with NMR/surface plasmon resonance (SPR) techniques. Furthermore, with more sophisticated techniques such as modification of membrane scaffold proteins (MSP), the use of Nanodisc may yield structural and functional insights into a wide variety of membrane proteins in a biologically relevant membrane environment.

This paper introduces embedding scripting environment in NMR spectrometer software. First, the concept of scripting languages is described, and the performance of several script parsers is compared. Secondly, the architecture of NMR software system is summarized, followed by discussions on the methods used to setup scripting environment with QtScript. Thirdly, some feasible solutions for scripting within the framework of NMR spectrometer software are developed. Lastly, some test results are reported and possible methods for improvement are proposed.

In this paper, a compact and flexible signal receiving system mainly designed for low-field MRI systems is presented, which is capable of sampling multi-channel magnetic resonance signals simultaneously at a high speed and demodulating them directly. A digital down conversion chip (AD6636) was used to demodulate and decimate the signals from the four channels in a quadrature way. Digital signal processing (DSP) methods were used to complete the configuration of AD6636 and read out the I/Q data either from all channels at once, or just from one channel of interest. The sampling speed of the system could reach 100 million samples per second, giving high signal-to-noise. The system can be applied in MRI system with magnetic field strength up to 1 T. The performance of the signal receiving system was demonstrated by experimental results.

The design and implementation of a frequency synthesizer with wide-band output frequency spanning, high resolution, and low phase noise level was proposed. The frequency synthesizer contains three sections: 1) a STM32 which serves as the synthesizer’s controller and provides a CAN bus interface for remote frequency control, 2) a clock distribution section which generates fixed frequency references and provides fine output frequency resolution, and 3) a triplemix section which operates in a drift canceling loop and alters the output frequency with a 30 MHz step. The frequency synthesizer design was used on a home-built 500 MHz NMR spectrometer. Its performance was demonstrated by sensitivity tests with ¹H NMR spectroscopy.

As one of the most important part of NMR spectrometers, broadband preamplifiers determine the sensitivity of the hetero nucleus channel. On the basis of RF circuit theory and the overall parameter requirements, a broadband preamplifier for high field NMR spectrometer was designed. In the 15 MHz~300 MHz, test results demonstrate that the designed preamplifier exhibits a gain of over 38 dB，in-band fluctuation less than 1.5 dB, the noise figure less than 1.2 dB, and the switching time of RF switch under 1.5  μs. The broadband preamplifier has a good performance, as illustrated by its small in-band fluctuation, low noise figure, high isolation of protecting circuit in transmitter mode, as well as an accuracy of working condition detection circuit. Experimental results of hetero nucleus such as ¹³C and ³¹P demonstrate that the broadband amplifier has high signal to noise of NMR signals, which is comparable with those of commercial broadband amplifiers.

Downhole fluid analysis is an important tool in real-time evaluation of the reservoir. The paper introduces Halliburton’s downhole NMR fluid analysis laboratory. The key techniques used in the analyzer were discussed in detail, as well as the methods for obtained fluid characteristics. NMR fluid analysis laboratory can be used to access a variety of important parameters of fluid and achieve real-time evaluation, thus provide a valuable complement to other NMR logging tools.

After hydrocarbon zone is penetrated, one part of the oil and gas keeps in rock samples, and the other part enters into drilling fluid. There are mud logging methods for measuring oil and gas contents in rock samples, and gas content in drilling fluid. But there is no existing method for measuring oil content in drilling fluid. With the deepening of exploration degree and development of drilling technology, cuttings and gas surveying often have no showings or lower showings.  It therefore has becoming increasingly difficult to find and evaluate hydrocarbon zone. Under such circumstance, it is essential to measure the oil content in drilling fluid. In this work, we used NMR T₂ spectrum to measure the contents of light oil and medium oil, and T₂-D spectrum to measure heavy oil content in drilling fluid. These methods provide valuable complements to the existing mud logging series, and can be used to improve oil layer finding ratio and evaluation precision ratio.

The principle and method of fuzzy recognition of NMR spectra based on maximum principle of membership were reviewed. The concept of fuzzy set for NMR spectra was first introduced, and then the membership function was given. By establishing library of standard compounds and algorithm of fuzzy recognition, a quick automatic qualitative analysis was achieved. ¹H NMR spectra of 11 mixed samples composed of 4 compounds were analyzed. The results show that the compounds in the samples can be recognized accurately even when the peak positions were only calculated roughly, and the threshold of average membership took value from 0.45~0.85.

Nineteen polyester compounds were synthesized, and utilized to study the ¹H  and ¹³C NMR chemical shift characteristics of polyacid units and polyol units in polyesters. We found that the type of polyol unit connecting to the polyacid unit does not have much influence on the ¹H  and ¹³C NMR chemical shift of the polyacid unit, and vice versa. On the basis of the experimental results, we established a chemical shift database for polyester units. With the aid of this database, the composition of unknown polyester can be determined quickly.

Free radicals play important roles in the metamorphic process, spontaneous combustion, pyrolysis and liquefacton of coal. Accurate quantitative determination of the free radical content in coal is important in studying the mechanism of coal pyrolysis and liquefaction. In this work, the stability and repeatability of quantitative measurement of total free radicals in coal by ESR method were investigated. With a standard curve method, the RSD of both stability and repeatability were less than 4%. The linearity of the method was in the range of 6.12×10¹⁵~1.47×10¹⁷, and correlation coefficient above 0.99.

Fexofenzdine hydrochloride is a second generation antihistamine drug. The complete and unequivocal assignments of the ¹H  and ¹³C NMR signals of the compound are not available so far. In this paper, we assigned all protons and carbons in the compound with 1D ROESY and 1D TOCSY experiments in combination with 2D NMR techniques. The configuration of the compound was also determined.

1,2∶4,5-di-O-isopropylidene-3-C-nitromethyl-β-D-ribo-hex-2-ulo pyranose was synthesized with high stereoselectivity. Its absolute configuration was confirmed. The ¹H  and ¹³C NMR signals of the compound were assigned using 1D and 2D techniques, including ¹H NMR, ¹³C NMR, gCOSY, gHSQC, gHMBC and ROESY.

The standard samples of heparin (HP) and oversulfated chondroitin sulfate (OSCS) were analyzed by ¹H NMR. The spectra were assigned. The results showed that the acetyl-methyl peaks of heparin and OSCS have different chemical shift, at δ2.04 and δ 2.15 respectively. The experimental conditions for quantitative analysis were studied. It was shown that, OSCS content in HP solution can be accurately measured under the following conditions: 25 mg sample in 0.6 mL D₂O, 0.020%（W/V）TSP, spinning rate 12 Hz, line broadening for EM window functions 1.0, and spectrometer frequency of 500 MHz.

The human A3G (apolipoprotein B messenger-RNA editing enzyme, catalytic polypeptide-like 3G) protein belongs to a family of polynucleotide cytidine deaminases, which is a human intrinsic immune protein with anti-viral activity. During the process of HIV virions replication, A3G is effectively incorporated into budding HIV-1 virions, catalyze C→U conversions, and then block viral replication, resulting in viral infectivity. In recent years, much attention has been paid on the structure and the process of deamination of A3G by NMR or X-ray, and significant research progress has been made, which might provide new ideal for further research. In this paper, we summarized these works in order to provide new reference for the prevention and treatment of AID’s and hepatitis B virus and the relative new drug design.

Dear colleagues and friends,

On behalf of the organizing committee, I would like to invite you to participate in the 11^th International Conference on Magnetic Resonance Microscopy (ICMRM), August 14~18, Changping, Beijing, China.
The 11^th ICMRM will follow the fine tradition that has been established in 1991 starting with the very first ICMRM in Heidelberg. The conference will be devoted to the latest developments in NMR methods, equipment, and applications of spatially resolved NMR techniques; it is also designed to provide a platform to enhance scientific communication between industry and academia, and between researchers from countries spanning the globe.
We have received more than 130 abstracts from many of the fine NMR laboratories worldwide, and also invited 22 renowned scientists to give presentations on various aspects of NMR, including Sir Paul Callaghan, Prof. Warren S. Warren, Prof. Axel Haase, Prof. Eiichi Fukushima, Prof. Bernhard Blumich and Prof. Bruce Balcom. In addition, more than 20 organizations, including CNPC, Shell, Niumag, Huanding, Bruker, Agilent, Oxford Instruments, JSR, and K. C. Wong Education Foundation, Hong Kong, etc. have agreed to provide financial support to this conference. We sincerely appreciate the generous donations from our industry friends and the enthusiastic assistance from the China University of Petroleum (CUP) and other Chinese research institutes. We would also like to thank in advance all the delegates and exhibitors for their interest in presenting their highquality work. We believe that all our attendees will greatly benefit from this conference.
We, the faculty and graduate students from CUP, are honored to organize the 11^th ICMRM.  CUP specializes in petroleumrelated researches and education and is one of the best industry-oriented universities in China. NMR is widely used for petroleum and natural gas exploration and recovery in well logging, and in core analysis to measure rock porosity and permeability, or to identify pore fluids. We are delighted to incorporate contributions from the Society of Core Analysts and have created a Joint Topic Conference on NMR in Well Logging and Core Analysis, and will specially focus on unconventional oil and gas core analysis.

This year, ICMRM will for the first time be held in China. In addition to the scientific program, we hope you will enjoy your trip to Beijing and China. Chinese civilization has endured and prospered for thousands of years, and Beijing has been the capital city for nearly 900 years. It is a city of both old and young at same time. Young with inexhaustible energy and an open attitude for new developments, it is one of the greatest cities in the world. We have arranged a wonderful excursion to show you the old and the young faces of Beijing on this special occasion.

To conclude this welcome note, I would like to quote Confucius, a famous Chinese philosopher, “How happy we are to have friends from afar!”  We look forward to welcoming you to Beijing this August. For more information, please check at http:∥icmrm11.cup.edu.cn.
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Sincerely yours,
 
Lizhi Xiao, CONFERENCE CHAIR, ICMRM 11

Professor and Dean
College of Geophysics and Information Engineering
China University of Petroleum, Beijing
Executive Committee Member, SRMR, AMPERE Society
Committee Member, China Society of Magnetic Resonance