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This paper studies two-step synthetic process of TEX (4,10-dinitro-2,6, 8,12-tetraoxa-4, 10-diazatetracyclo-[5. 5. 0. 05,9 03,11]-dodecane) and the effects of key factors on the yield of DFTHP (intermediate) and TEX. The results show that the yield of DFTHP could reach to 68. 3% when the adjusted pH value of reaction solution reaches to 9 by saturated NaOH solution. When the volume ratio of fuming HNO3 to concentrated H2SO4 is 3 : 2, and the ratio of nitrating agent (mL) to DFTHP(g) is 3 : 1, the yield of TEX raises to 59. 7% . The optimized overall yield of TEX obtained from two-step synthetic process could be 40. 8%. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of DDD pacing on vasovagal syncope (VVS)., Methods: Eleven patients diagnosed VVS (7 with heart inhibiton type, 4 with combination type)by tilt table test (TTT) in Shanghai Chest Hospital were selected into the study. They all were implanted DDD pacemaker in whom 9 with rate-drop response (RDR) function. All of them were prescribed beta-receptor blocker. The patients were followed-up at 1, 3, 6, 12, 24 months after being discharged., Results: All the 11 patients with pacemaker implantation were free from syncope, in whom 4 still had pre-syncope discomfort, but the symptoms were slightly. Six patients took TTT again after pacemaker implantation. It was observed that pacing at an elevated rate started immediately when heart rate dropping to the lower threshold, and as a result syncope were prevented., Conclusion: In the VVS patients with recurrent syncope and severe heart inhibition, DDD pacing with RDR function could prevent from syncope efficiently.