A photochemical reaction model of focal cerebral ischemic injury in rat was demonstrated by means of T₂-weighted MRI. The NMR images were obtained by adding together the different T₂-weighted data during raw data acquisition. The ischemic injury region cna be found clearly in the T₂-weighted MRI images in one hour after the onset of the cerebral ischemia in rats. It is confirmed that the T₂-weighted MRI approach has great potential in studying the cerebral ischemia.

Objective:To study whether the changes of ³¹P MRS parameters of mouse S180 sarcoma treated by Taxol is earlier than the changes of tumor volume. Methods:Mouse S180 sarcoma (i.p.) was studied by using surface-coil ³¹P NMR. Results:After 48h following treatment, PCr/Pi and β-NTP/Pi ratios of treated groups are higher than those of control group (P <0.05), PME/β-NTP ratio of treated groups is lower than that of control group (P <0.05). The tumor volume between treated groups and control group showed no significant difference. Conclusion:³¹P MRS of mouse S180 sarcoma can offer not only quantitative information, but show also earlier response to therapy.

t₁ noise, stemming from the instabilities of pulse phases in 2D spectroscopy, has been investigated theoretically as well as experimentally. Based on the angular momentum operator I_x,I_y,I_z formalism, our deductions show that the different precessing directions of the magnetization between P-type and N-type gradient enhanced DQF-COSY experiments result in that P-type gradient enhanced DQF-COSY experiments refocus the phase errors of pulses, while N-type gradient enhanced DQF-COSY experiments strengthen the effect of the phase errors of pulses. Therefore, t₁ noise in P-type gradient enhanced DQF-COSY experiments is lower than that in N-type. In addition, the theoretical ratio of P-type to N-type is √3:√11, which is supported by our experimental results.

NMR two dimensional (2D) exchange spectroscopy (EXSY) is used to study the exchange dynamics of mobile protons in a small pseudopeptide Cbz-Ser-Tyr-OC₆H₁₃. It is shown by a quantitative study that the exchange rates for the four mobile protons in this molecule with water are in the order Ser-OH~Tyr-OH > Ser-NH > Tyr-NH, under the given experimental conditions with dimethylsulfoxide and chloroform as solvents. Local structures for the amino groups in different solutions are described.

The conformation of spirobiscalix [4] arene-crown-3 in solution is studied by NMR. Chemical shift assignments of ¹H and ¹³C indicate that this molecule takes the cone conformation at room temperature. Using the data of 2D NOESY spectra the distances between the protons are estimated by the isolated spin pair approximation through molecular modeling calculations. Exchange rates between the hydroxyl protons and the trace water in the solvent are also evaluated.

A derivative component separated from bear bile fluid was identified to be 2-[[(5β,7α)-7-hydroxy-3,24-dioxochoian-24-yl] amino]-ethanesulfonic acid using ¹H and ¹³C NMR spectroscopy. A number of two dimensional NMR methods were used for the structural determination and spectral assignment of the compound.

The relaxation character and glass transition temperature of crystalline poly (methyl methacrylate)(PMMA) have been studied by means of NMR and DSC techniques. Compared with amorphous PMMA, the ¹³C CP/MAS spectra of the crystalline one has similar band shape, band width and chemical shifts. α-CH₃ carbon resonance exhibits two bands with a very asymmetrical shape, which may be related to conformational structure in sequence of the so-called γ-gauche effect. The two values of the proton spin-lattice relaxation time in rotating frame T_1ρ (H) observed correspond to amorphous and crystaline structure respectively dectected by inverse gated decoupling. Aggregated structure wasn't detected by NMR means.

A new 3,28-bidesmosidic triterpenoid saponin was isolated from the ethanolic extract of the root of Dipsocus asperoides C.Y.Cheng et T.M.A. and its structure established as 3-O-[α-L-rhammopyranosyl(1→3)][-β-D-glycopranosyl(1→4)]-β-D-glycopranosy(1→3)-α-L-rhammopyranosyl (1→2)-β-L-arabinopyranosyl-hederagenin-28-O-β-D-glycopranosyl (1→6)-β-D-glycopranoside. The sites of glycosylation and the sequence of sugars in the glycoside can be determined unambiguously and total assignment of severely overlapping proton resonance of sugar residues were achieved by a combined use of the 1D SEMDY, NOE difference spectroscopy in rotating frame and selective long-range DEPT techniques.

EPR spectra of VO-Met and VO-Met Phen systems in glycol and water (1:1) solution at various acidities have been observed at low temperature. It was found that in different pH ranges different structural complexes were formed. According to Johnson's rule and IR, their possible structures were suggested. The bonding parameters of complexes were calculated by EPR parameters. It can be seen that the δ² of complexes decrease as the number of ligands bound to vanadium increase. This means that the covalent bonding between vanadium and ligands increase as amino acid ligands replace water ligands. Using electronic spectral data, the crystal field parameters were calculated. The coordination law was discussed. It was obtained that the coordination capacity of phen is much stronger than one of Met.

The electronic configuration of Gd(Ⅲ) is 4f⁷. Stronger Spin Spin interaction existing between 7 unpair electrons, bring about the EPR spectra overlap mutually, and results an envelope line. Useful information could not obtain practically, and limited the EPR spectra application to this field. Using a simulation program resolve out each spectrum and determine their g-values from envelope line at first, then using another program calculated the Zero-field Splitting Tensors D and E according to above obtained g-value, were reported in this paper. These two programs are edited by ourselves. Applied to analysis of EPR spectra of 5 Gd(Ⅲ) different β-diketone complexes, calculated their Zero-field Splitting Tensors D and E, satisfactory results were obtained.

In this article, ¹H and ¹³C NMR spectra of Gestodene were analyzed by using two-dimensional ¹H-¹H COSY, heteronuclear ¹H-¹³C shift correlation and HMBC, It was made possible to assign ¹H and ¹³C NMR spectra of Gestodene completely by combination of these techniques, Gestodene showed complex ¹H signal around 1.4-2.6ppm and ¹³C signals around 25.3-38.13ppm, This combination of techniques is applicable for assignment of highly overlapping signals, The HMBC spectra can provide valuable information for assignment of ¹H and ¹³C NMR signals.

Optimizing phase alternating composite π pulses were described by using Wigner rotation matrix and modified Levenberg-Marquardt algorithm. The subroutines DBCLSF and QRDCMP were programed instead of "IMSL" subroutine library to solve the non-linear least square problems. The calculations were carried out on COMPAQ 586 personal computer, it was found that the optimized results were in agreement with that reported in the reference being obtained from IBM/3600 computer and better than other existing composite π pulses.

Six new tail-porphyrin triethylamine and pyridine quaternary ammonium salts were synthesized. Their structures were confirmed by elemental analysis, NMR and IR. Some characteristics of ¹H NMR、¹³C NMR spectra among the different quaternary ammonium salts were discussed.

Six new different chain-length tail-porphyrin triethylamine and pyridyl quaternary ammonium salts were synthesized. Their structures were confirmed by elemental analysis, NMR, IR and UV. Some characteristics of ¹H NMR spectra among the different quaternary ammonium salts were discussed.