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991.
Pentisomide, 2-(2-diisopropylaminoethyl)-4-methyl-2-(pyridyl)- pentanamide, is a novel antiarrhythmic agent structurally related to disopyramide. Using a glass bead arrhythmic model, the authors studied the antiarrhythmic effect of pentisomide in dogs by monitoring the plasma concentrations. When pentisomide was infused at 1 mg/kg/min for 20 min, the ventricular tachycardia was significantly reduced at 5 min after starting the infusion; the arrhythmias were reduced to less than 5% at the end of the 20 min infusion. The plasma-free concentration of pentisomide was about 3 micrograms/ml at 5 min; it increased to about 10 micrograms/ml at the end of 20 min infusion. With 0.3 mg/kg/min infusion, the arrhythmias were reduced to about 60% but were not significant at 20 min of infusion. The plasma-free concentration of pentisomide did not reach 3 micrograms/ml until 20 min of infusion. The 3 micrograms/ml plasma-free concentration for pentisomide seems to be a critical concentration in inducing a significant antiarrhythmic effect. Pentisomide dose-dependently inhibited ischaemia-reperfusion arrhythmia at doses of 30 microM and higher concentrations in vitro. In conclusion, pentisomide inhibits arrhythmias dependent with the plasma concentration or with the concentration of the external solution. The critical plasma-free concentration for inhibition of arrhythmias was 3 micrograms/ml (not equal to 10 microM) and the in vitro effect also had a similar concentration. Therefore, the in vivo and in vitro antiarrhythmic concentrations were well correlated.  相似文献   
992.
In this study, 16 cases of unilateral alveolar cleft with cleft lip and palate were repaired with autografts of cancellous bone (13 cases) or hydroxyapatite (3 cases). The grafts were covered by reflected mucoperiosteal flaps and a mucosal flap from the upper lip. Twelve of the thirteen cases were followed up for 1-5 years. Nine of whom using cancellous bone had bony continuity of the maxilla and 7 cases erupted permanent maxillary canines within the area of autografts. None of the 3 cases using hydroxyapatite erupted a canine tooth. The results showed that autograft was better than hydroxyapatite in terms of maxillary canine eruption.  相似文献   
993.
陈正初 《大电机技术》1995,(1):55-58,F004
本文对电液调速器的人工失灵区电路进行定量分析,导出了失灵区的一套计算公式,并指出失灵区与调差率、功率偏差的内在关系。  相似文献   
994.
There is agreement on the clinical diagnostic criteria for acute inflammatory demyelinating polyneuropathy (AIDP/GBS) however, there is lack of consensus for detection of demyelination. In order to critically evaluate the prevailing criteria, sixty-six patients who fulfilled NINCDS criteria and had typical features of GBS were studied for electrophysiological abnormalities of peripheral nerves by using standard methods (median, common peroneal, sural and ulnar) between 1 to 12 weeks after the onset of symptoms. The commonest abnormality on motor nerve conduction study was prolonged distal latency (75%-83%) followed by reduction in CMAP amplitude (63%-82%), decreased velocity (48%-62%), conduction block (17%-39%) and f-wave abnormalities (37.8%-59%). Sensory conduction abnormalities were detected in over 20% of median, 25% of ulnar and 33% of sural nerves. All the patients had abnormality of at least two motor conduction parameters in one nerve when values beyond 2 SD of the mean were considered abnormal and over 70% of patients had three abnormalities in two nerves or two abnormalities in three nerves. Comparison with the prevailing criteria for demyelination revealed that the number of patients fulfilling them varied widely: Albers et al. (1985): 74.2%, Albers et al. (1989): 40.9% and Cornblath: 30.3%. We believe that the current criteria for detection of demyelination in acute neuropathy are too strict, underestimate the underlying pathology in GBS and need reassessment.  相似文献   
995.
本研究了几种不酸PH值对硅酸胶结的影响。结果表明,草酸浓度增大时,硅酸胶结速度变缓,至PH3-4时,硅酸不再胶结;而HCL浓度增大,虽然胶结速度变缓,但最终仍胶结。  相似文献   
996.
分别用7.48J/cm~2和14.96J/cm~2能量密度的氦氖激光辐照23份液氮冷冻前人的精液,冻贮三个月后复温查精子活率和毛细管穿透高度。结果:经7.48J/cm~2剂量的激光辐照后的精子活率和穿透高度明显提高,分别平均提高10.18%和8.32mm,与未受辐照组比较差异显著(P<0.05)经14.96J/cm~2辐照组,活率较未照组降低。实验结果说明适当剂量的激光辐照能够增强精子对冷冻的耐受力,提高精子的复活率和活动力。  相似文献   
997.
Protoporphyria is a genetic disorder in which patients may develop severe protoporphyrin-induced liver damage and require transplantation. Because unique problems occur in the perioperative period and because excess production of protoporphyrin by the bone marrow continues after liver transplantation, the efficacy of this procedure for protoporphyric liver disease is uncertain. We present follow-up of nine patients who underwent liver transplantation. Two patients died within 2 months of transplantation, one from complications of abdominal bleeding and the other from sepsis after bowel perforations. The remaining seven patients had follow-up at 14 months to 8 years after transplantation (mean, 3.8 years). Two of the seven had suffered skin burns from exposure to operating room lights, which healed without scarring. Three had axonal neuropathies in the postoperative period requiring prolonged mechanical ventilation, and motor defects persisted in two. Five patients had normal liver chemistries at follow-up (mean, 3.5 years), with liver biopsy results normal or showing mild portal triad abnormalities, but erythrocyte protoporphyrin levels remained significantly elevated (1,765 +/- 365 mcg/dL; normal, < 65). The other two patients, both of whom had rejection, cytomegalovirus infection, and biliary tract obstruction requiring endoscopic therapy, had a recurrence of protoporphyric liver disease as indicated by liver biopsy features. One died 5 years after transplantation from complications of the liver disease. The other was stable 3.3 years after transplantation and was being monitored for possible retransplantation. Thus, liver transplantation can be performed successfully in patients with protoporphyric liver disease, with intermediate survival rates comparable to the general transplant population. However, disease may recur in the graft, particularly if there are complications that cause cholestasis.  相似文献   
998.
999.
Extremely low frequencies (ELFs) are employed to transmit data from underground to the ground surface in the measurement-while-drilling electromagnetic (MWD-EM) telemetry system. Based on electromagnetic field theory, the present work is aimed at predicting the receivability of the signals at the surface. A unified analytic method that is suitable for vertical, directional, or horizontal wells is presented. Attenuation properties are examined for various parameters, including the Earth's conductivity, operating frequency and the length of the drill string. The frequency dependence of the receivability in reference to a noise level is illustrated for different depths of well and different cases. It is also demonstrated that the electric field distributions at the surface have the same features for the three types of well, and that the measurements should be carried out near the well heads for any type of well. A scale model experiment is made to test the authors' theoretical results. The measured data and the computed results are comparable  相似文献   
1000.
光绪三十二年(1906),新疆布政使王树木丹组织了油苗普查,引进了钻采设备,在独山子开展了新疆石油工业的草创工作,但这项新兴的事业很快随清朝的灭亡而衰落了。民国7~12年(1918~1923),新疆省长杨增新再次组织石油采炼,但因经费不足,没有很大起色,而地方人士潘祖焕在汪家沟设厂,却首创了略有盈利的采炼实业,为新疆石油工业的二次兴盛作了贡献。本世纪40年代初,中苏合作,在独山子油矿建成了相当大的生产经营规模,新疆石油工业出现了第三个鼎盛时期。后来由于盛世才投靠国民党,反共反苏,与苏联关系恶化,独山子的石油采炼如昙花一现,迅速走向衰落。  相似文献   
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