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31.
A number of factors affecting the stability of propranolol HC1 during electrophoretic control were investigated. It was found that significant degradation of propranolol HC1 and hydrolysis of water occurred when a current of 15 mA was used with platinized electrodes. This degradation was thought to be due to decomposition of propranolol HC1 at the electrodes. Degradation could be significantly reduced by using uncoated platinum electrodes and currents in the range of 0 to 2.5 mA, while still allowing control of drug delivery rates. Electrode reaction processes were found at high ionic strengths and high drug concentrations but were not thought to be associated with drug decomposition. 相似文献
32.
荔枝壳红色素的提取及稳定性观察 总被引:4,自引:0,他引:4
以荔枝壳为原料,在酸性条件下浸提荔枝壳红色素,并对其稳定性进行了研究,结果表明,该色素在酸性条件下对光、热、常用食品添加剂均具有较好的稳定性。 相似文献
33.
单一的稳定剂并不能解决甘蓝复合果蔬汁的稳定性问题,而多种稳定剂的稳定效果较好,为此挑选出较好的3种稳定剂,对其进行不同比例的复配,观察一段时间的相对粘度及浊度变化,发现两种稳定剂的复配就能达到稳定的效果,最佳添加量(质量分数)为果胶0.07%,黄原胶0 03%. 相似文献
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T. K. Moroz J. B. Finlay C. H. Rorabeck R. B. Bourne 《Medical & biological engineering & computing》1988,26(3):271-276
Detailed data of the stability of external fixation devices are needed by the orthopaedic surgeon to predict successful healing
of a fracture. The stability (rigidity, yield and failure criteria) of four half-frame configurations (single, stacked, double
and delta) of the original Hoffmann and AO tubular frame have been analysed under four loading conditions: axial compression,
torsion, and both AP- and ML-bending. Overall the two systems' rigidities were the same between similar configurations. Both
systems' single half-frames were particularly weak; however, as the number of components (rods, pins, clamps, couplings) on
the frame increased, the rigidity of the frame increased. The difference in performance between the two systems lies in their
yield and failure characteristics. The AO system exhibited excellent failure criteria in all modes of loading, i.e. no configuration
failed within the test limits, whereas most Hoffman frames yielded and failed at low loads. 相似文献
36.
本文用生物伯德图分析了血压稳定性。按照经典的控制理论,讨论了生物系统的稳定性,提出了血压控制的数学模型。根据生物特点,建立了生物伯德图的表达式。作为系统稳定性的指标,增益裕量和相位裕量可以用作图法求得,也可以用计算机求解。实验结果与理论分析能很好地符合。 相似文献
37.
妊娠相关血浆蛋白A水平与不稳定心绞痛患者冠状动脉狭窄病变形态的关系 总被引:2,自引:2,他引:0
[目的]探讨不稳定型心绞痛患者妊娠相关血浆蛋白(PAPP-A)水平与高敏C-反应蛋白(hs-CRP)及动脉粥样硬化斑块稳定性的关系.[方法]不稳定型心绞痛组患者42例,稳定型心绞痛组38例.冠状动脉造影前检测PAPP-A和hs-CRP,根据造影结果将冠状动脉病变分为复杂狭窄和光滑狭窄.[结果]稳定型心绞痛组有28例(74%)患者至少有1支血管狭窄≥70%,多于不稳定型心绞痛组的24例(57%),P<0.05;不稳定型心绞痛组中33例(79%)有1处以上的复杂狭窄,多于稳定型心绞痛组(22例,58%,P<0.05);PAPP-A与hs-CRP正相关(r=0.44,P<0.001);不稳定型心绞痛组与稳定型心绞痛组相比,hs-CRP(4.40 mg/L±0.003 mg/L vs 0.48 mg/L±0.016mg/L,P<0.001)和PAPP-A(18.40×10-3 U/L±0.002×10-3U/Lvs 7.79×10-3 U/L±0.001×10-3 U/L,P<0.001),差异均有统计学意义;两组中有复杂狭窄者的PAPP-A和hs-CRP水平显著高于无复杂狭窄者.[结论]PAPP-A可作为评估冠状动脉斑块稳定性的血清学指标之一. 相似文献
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PURPOSE: To evaluate the effects of dissolvable collagen punctal plugs on the symptoms, tear stability and volume in aqueous deficient dry eyes. METHODS: Sixty-two aqueous deficient dry eye patients of mixed aetiology underwent lacrimal punctal occlusion with dissolvable collagen plugs. The subjects were randomly allocated to one of two treatment groups: group I (n = 36) had their lower puncta occluded and group II (n = 26) had both their upper and lower puncta occluded. The effectiveness of this treatment was clinically assessed by (1). scoring subject symptoms and (2). measuring the tear parameters of tear thinning time (TTT) and tear meniscus height (TMH) as indicators of tear stability and volume, respectively. Following baseline measurements, patients were reviewed at time intervals of 5 and 12 days post-occlusion. A group of age- and gender-matched normals (n = 45) was recruited for comparison (group III). RESULTS: Tear volume and stability were significantly higher in group III compared with I and II at baseline. In the treated groups on both days 5 and 12: (1). symptom score reduced significantly from a median value of 7 to 3 (p = <0.001); (2). tear stability increased significantly from a median value of 3 to 5 s by day 5 (p stability in group III at all times; (c). tear volume increased significantly by day 5 in both treatment groups from a median value of 0.13 to 0.20 mm (pstability. CONCLUSION: Collagen plugs improved tear status in the aqueous deficient dry eyes. Occluding both upper and lower puncta with temporary collagen plugs offers no practical beneficial gain compared with occluding just the lower punctum. 相似文献