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A pair of enantiomeric 15-nordolabellane diterpenoids, (−)- and (+)-caseadolabellols A (1aand 1b), three dolabellane diterpenoids, caseadolabellols B–D (2–4), two dolastane diterpenoids, caseadolastols A and B (5and 6), 10 clerodane diterpenoids, caseakurzins A–J (7–16), and nine known diterpenoids (17–25) were isolated from the twigs and leaves of Casearia kurzii. The structures of the new compounds were established on the basis of extensive spectroscopic data, and those of compounds 1a, 1b, and 2were verified by single-crystal X-ray crystallographic analysis. The enantiomers 1aand 1bwere separated by chiral-phase HPLC. The absolute configurations were determined by experimental and calculated ECD data, the modified Mosher’s method, or literature comparison. Compounds 1aand 5showed significant quinone reductase-inducing activity in Hepa 1c1c7 cells, while 1bshowed moderate activity. Molecular docking studies showed that 1ahad greater binding affinity with Nrf2 protein (5FNQ) than 1b. The cytotoxic activity of compounds 1a, 1b, 2–12, 15, and 16was evaluated, among which compounds 8and 16exhibited significant inhibitory activity against the A549 cell line. Compounds 8and 16induced the A549 cells to arrest at G2/M and S phases, respectively, and both compounds induced apoptosis in A549 cells.

The phytochemical study of Euphorbia proliferaled to the isolation of two tiglianes (1and 2) and 23 mysrinanes (3–25). Most of these isolates showed significant antiadipogenic activity in 3T3-L1 adipocyte without apparent cytotoxicity. Subsequent structural modification yielded 10 derivatives, among which 1a, the 5-O-acetyl derivative of 1, turned out to be the most active compound with improved triglyceride-lowering activity (EC50for 1and 1a: 0.61 and 0.32 μM, respectively) and reduced cytotoxicity (selectivity index for 1and 1a: 28 and 312, respectively). The structure–activity relationship study revealed that the trans-fused 5/7/6 ring system in an angular shape was important to the activity. A mechanistic study indicated that 1and 1acould inhibit the glucocorticoid receptor α-Dexras1 axis in adipocyte, leading to the retardation of cell differentiation at the early stage. These findings may provide a new type of lipid-lowering agents for future antiobesity drug development.

The proton beam energy determines the range of particles and thus where the dose is deposited. According to the depth of tumors, an energy degrader is needed to modulate the proton beam energy in proton therapy facilities based on cyclotrons, because the energy of beam extracted from the cyclotron is fixed. The energy loss was simulated for the graphite degrader used in the beamline at the superconducting cyclotron of 200 MeV in Hefei (SC200). After adjusting the mean excitation energy of the graphite used in the degrader to 76 eV, we observed an accurate match between the simulations and measurements. We also simulated the energy spread of the degraded beam and the transmission of the degrader using theoretical formulae. The results agree well with the Monte Carlo simulation.

The design, field quality optimization, multipole field analysis, and field measurement of a dipole for a newly developed superconducting proton cyclotron (SC200) beamline are presented in this paper. The maximum magnetic field of the dipole is 1.35 T; the bending radius is 1.6 m with a proton beam energy in the range of 70–200 MeV. The magnetic field was calculated with 2D and 3D simulations, and measured with a Hall mapping system. The pole shim and end chamfer were optimized to improve the field quality. Based on the simulated results, the multipole field components in the good-field region were studied to evaluate the field quality. The results showed that the field quality is better than ± 5 × 10−4at 1.35 T with shimming and chamfering. For the transverse field homogeneity, the third-order (B3) and fifth-order (B5) components should be controlled with symmetrical shims. The second-order (B2) component was the main disturbance for the integral field homogeneity; it could be improved with an end chamfer. The magnet manufacturing and field measurement were performed in this project. The measurement results demonstrated that the magnetic design and field quality optimization of the 45° dipole magnet can achieve the desired high field quality and satisfy the physical requirements.

To meet the demands on proton therapy in Russia and China, JINR and ASIPP have started to develop a proton therapy facility based on an isochronous superconducting proton accelerator. A 200 MeV/500 nA proton beam will be extracted from the SC200 superconducting proton cyclotron. Due to the energy of the cyclotron being fixed, an energy selection system (ESS) is employed to degrade such energy in order to match the particle energy to a shallower depth. In this article, calculation of beam optics, analysis of beam transmission, and correction of orbit distortion are presented. Studies show that the main factors influencing transmission efficiency of the SC200 ESS beamline are the degrader, collimator, slit, vacuum system, beam diagnostic system, and trajectory correction system. Through the beam optics study, the designed ESS beamline can provide 70–200 MeV proton beam to a treatment room, with a maximum emittance of 24 π mm mrad. Also, the controllable momentum spread ranges from 0.1 to 1.0%, which is equivalent to an energy spread from 0.193 to 1.93%. The transmission efficiency about 0.204% can be obtained when the emittance is 24 π mm mrad with an energy spread of ± 0.6%.

Studies on beam optics and the isocenter property in the gantry system for the SC200 (Superconducting Isochronous Cyclotron of 200 MeV in Hefei, China) are presented in this paper. The physical design of the isocentric gantry system is developed with the software TRANSPORT, which realizes a beam with a circular shape at the isocenter and a full width at half maximum of 4–10 mm. For stereotactic radiosurgery, the isocenter deviation of the gantry system should be less than 1 mm in diameter. In order to explore the property of the isocenter, an electromagnetic structure coupling analysis has been conducted given the self-gravity and the electromagnetic (EM) force of the magnets on the gantry beam line. The correlation between the isocenter property and the EM force has also been carefully studied. This paper puts forward two methods to obtain the isocenter deviation based on the characteristics of the nozzle installation structure and the calculation of the optical path after the nozzle, respectively. The results show that the maximum isocenter deviation is less than 0.33 mm with a safety factor of 1.5, and the deviation caused by the EM force is 0.05 mm. The latter result indicates that the impact of the EM force is negligible. This paper puts forward one possible way to realize real-time acquisition of the isocenter deviation in practical application. The gantry of SC200 is under construction at ASIPP.

Two polyprenylated acylcyclopentanone racemates, evodialones A (1) and B (2), featuring a 3-ethyl-1,1-diisopentyl-4-methylcyclopentane skeleton, were isolated from an extract of the aerial parts of Evodia lepta. Evodialone A (1) was resolved by chiral-phase HPLC to afford a pair of enantiomers, (+)- and (−)-evodialones A (1b/1a), while evodialone B (2) could not be resolved. Their structures were elucidated by spectroscopic analysis and a combination of computational techniques including gauge-independent atomic orbital calculation of 1D NMR data and experimental and TDDFT-calculated ECD spectra. A putative biosynthetic pathway of 1and 2starting from the monocyclic polyprenylated acylphloroglucinols is proposed. All the isolates were screened for the antimicrobial activity in vitro, and 1aand 1bshowed moderate inhibitory activities against several pathogenic fungi with MICs values of 17.1–68.3 μM.

A systematic cutting test was conducted turning normalized AISI1045 carbon steel with two kinds of Ti (C, N)-based cermet cutters, which were made with micron and nanometer TiC powders. And the cutting performance and abrasion mechanism was discussed in the article. The effect of tool orthogonal clearance on tool life was also researched in this paper. Results showed that: The tool life was affected seriously by tool orthogonal clearance angle, and the optimum tool orthogonal clearance angle of Ti (C, N)-based cermet cutter was 5°when cutting normalized AISI1045 steel. The cutting Performance of Ti (C, N)-based cermet cutters which were made with nanoTiC powders was better than the ones which were made with micron TiC powders obviously. And the primary wear behaviors were wear.

Four kinds of X100 grade pipeline steels containing different chromium content were designed and corrosion behavior were studied in order to confirm the influence of Cr on the properties of high grade pipeline steel. The corrosion experiments demonstrated that Corrosion rates of Four steels in the experiment decrease with the increasing of Cr content, and the scales on the four steels have a two-layer structure under the corrosion of CO2 and H2S. The outer layer is mainly composed of FeS or FeS1-x and the inner layer consisted of FeCO3. Cr enriches in the inner layer and Cr content of the inner layer increases with the Cr content in matrix. The Cr enrichment enhanced the compactness of the scales further hindered the diffusion of ions from liquid to the surface of steel. The corrosion scale with Cr(OH)3 is anion-selective and reduce the amount of anion reaches metal surface, thus reducing corrosion rate.

The influence of Sn on mechanical properties and CO2 corrosion resistance of oil tube was investigated by TEM, EBSD and electrochemical measurement. The results show that the addition of 0.05%Sn can improve the corrosion-resistance of tested steel, but decrease the elongation and impact energy. Sn affected the activity of tested steels, moved corrosion potential to negative potential and decreased corrosion current density. Consequently, the polarization resistance of electrode reaction increased and corrosion reaction was slowed down due to the effect of Sn. In addition, Sn increased the proportion of low boundary, which improved the corrosion resistance of steel, and accordingly decreased the proportion of large angle grain boundary, which contaminated the elongation and impact energy of steel. However, Sn had little influence on the microstructure, precipitates of steel. And thus the strength of steel did not change obviously.