A strategy for rapid identification of the chemical constituents from crude extracts of Tribulus terrestris was proposed using an informatics platform for the UHPLC/Q-TOF MS data analyses. This strategy mainly utilizes neutral losses, characteristic fragments, and in-house library to rapidly identify the structure of the compounds. With this strategy, rapid characterization of the chemical components of T. terrestris from Beijing, China was successfully achieved. A total of 82 steroidal saponins and nine flavonoids were identified or tentatively identified from T. terrestris. Among them, 15 new components were deduced based on retention times and characteristic MS fragmentation patterns. Furthermore, the chemical components of T. terrestris, including the other two samples from Xinjiang Uygur Autonomous region, China, and Rome, Italy, were also identified with this strategy. Altogether, 141 chemical components were identified from these three samples, of which 39 components were identified or tentatively identified as new compounds, including 35 groups of isomers. It demonstrated that this strategy provided an efficient protocol for the rapid identification of chemical constituents in complex samples such as traditional Chinese medicines (TCMs) by UHPLC/Q-TOF MS with informatics platform. Graphical Abstract ᅟ.

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Twelve new steroidal saponins, including eleven furostanol saponins, terrestrinin J-T (1-11), and one spirostanol saponin, terrestrinin U (12), together with seven known steroidal saponins 13-19 were isolated from T. terrestris. The structures of the new compounds were established on the basis of spectroscopic data, including 1D and 2D NMR and HRESIMS, and comparisons with published data.

Based on Umansky’s second theory, this paper studies the torsional stress of an improved composite box girder with corrugated steel webs and considers the effective elastic modulus of the converted section. The calculation formulas of the torsional stress of a single-box multi-cell-improved composite box girder with corrugated steel webs were derived, the initial parameter solution of the generalized displacement and internal force under the restrained torsion were obtained through a model test and finite element simulation, the correctness of the theoretical formulas were verified, the distribution forms of the torsional stress on the box girder section were analyzed, and the effects of the height/width ratio, the width ratio of the cantilever plate, and the thickness of the bottom steel flange on the torsional stress were studied. The results show that the theoretical values and finite element values are in good agreement with the measured values for the torsional stress at each measuring point, and the errors are within 10%. The torsional normal stress of the bottom steel flange of the box girder is much greater than that of the top concrete flange, and the corrugated steel web hardly bears the torsional normal stress. The total shear stress of the box girder is mainly borne by the corrugated steel web on both sides and the bottom steel flange and less by the top concrete flange. The greater height/width ratio, the greater the difference between the torsional normal stress of the bottom steel flange and the top concrete flange. For a box girder with small height/width ratio, the total shear stress of each plate is significantly greater than that of a box girder with large height/width ratio.