Numerical Simulations and the Design of Magnetic Field-Enhanced Electron Impact Ion Source with Hollow Cylinder Structure.

An electron impact ion source-adopted magnetic field-enhanced technology has been designed for enhancing the electron intensity and the ionization efficiency. Based on the ion optic focus mechanism, an electron impact ionization source was designed, and the electron entrance into the ionization chamber was designed with a hollow cylinder structure to improve the ion extraction efficiency. Numerical simulation and optimal geometry were optimized by SIMION 8.0 to provide higher electron intensity and ion transmission efficiency. To improve the electron intensity, the influence of the filament potential and magnetic intensity was investigated, and the values of 70 eV and 150 Gs were chosen in our apparatus. Based on the optimal parameters, the air in the lab and oxygen gas was detected by the homemade apparatus, and the ion intensity was detected in the positive and negative ion modes, respectively. The homemade electron impact ion source apparatus has the potential to enhance ionization efficiency applied in the mass spectrometer ionization source.

[Effects and mechanisms of autophagy of trophoblast cells in severe preeclampsia].

AIM: To investigate the occurrence law of autophagy in trophoblast cells from severe preeclampsia and its possible mechanisms of wrecking cells. METHODS: 23 cases of placenta tissues were collected from women suffer from severe preeclampsia and normal pregnant women respectively. Surface villous of placental was observed by scanning electron microscope, and ultrastructure and autophagosome of trophoblast cells were observed by transmission electron microscopic. The expressions of Beclin-1 and LC3II in placenta tissues were detected by Immunohistochemical technique, then its relevance whit weight of fetus and placental was analyzed. RESULTS: Compared with the control group, villous were decrease in placenta tissue from patients suffer from severe preeclampsia, and its arrangement was disordered; typical autophagosomes of trophoblast cells were observed by transmission electron microscope. The expression of Beclin-1, LC3IIwere significantly up-regulated in placenta tissue from patients suffer from severe preeclampsia.The correlation coefficient of Beclin-1, LC3II and placental weight, fetal weight respectively were -0.977, -0.930, -0.812, -0.849. CONCLUSION: Autophagy were significantly up-regulated in trophoblast cells from patients suffer from severe preeclampsia by increasing expression of Beclin-1, LC3II protein, and its expression was negatively related to weight of fetus and placental.