排序方式: 共有76条查询结果,搜索用时 62 毫秒
51.
研究了Er, Co-卟啉配合物((TMOPP)Er[P(=O)(OEt)2]3Co(η5-C5H5))的电化学行为, 并比较了它与相应的单核配合物电化学行为的差异.该配合物在 CH2Cl2 溶液中有四对氧化还原峰, 其氧化还原过程分别与配合物的中心离子和配体有关.而当该配合物修饰的玻碳电极于NaClO4溶液中时, 同样出现四对氧化还原峰, 但是峰的位置、形状、大小与前者比较发生了很大的变化.进一步实验又表明, 溶液的电解质浓度、酸碱性、种类以及膜的厚度等对修饰电极的反应行为都产生影响. 相似文献
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Ultrasound-mediated transdermal drug delivery of fluorescent nanoparticles and hyaluronic acid into porcine skin in vitro
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Transdermal drug delivery(TDD) can effectively bypass the first-pass effect. In this paper, ultrasound-facilitated TDD on fresh porcine skin was studied under various acoustic parameters, including frequency, amplitude, and exposure time. The delivery of yellow–green fluorescent nanoparticles and high molecular weight hyaluronic acid(HA) in the skin samples was observed by laser confocal microscopy and ultraviolet spectrometry, respectively. The results showed that,with the application of ultrasound exposures, the permeability of the skin to these markers(e.g., their penetration depth and concentration) could be raised above its passive diffusion permeability. Moreover, ultrasound-facilitated TDD was also tested with/without the presence of ultrasound contrast agents(UCAs). When the ultrasound was applied without UCAs,low ultrasound frequency will give a better drug delivery effect than high frequency, but the penetration depth was less likely to exceed 200 μm. However, with the help of the ultrasound-induced microbubble cavitation effect, both the penetration depth and concentration in the skin were significantly enhanced even more. The best ultrasound-facilitated TDD could be achieved with a drug penetration depth of over 600 μm, and the penetration concentrations of fluorescent nanoparticles and HA increased up to about 4–5 folds. In order to get better understanding of ultrasound-facilitated TDD, scanning electron microscopy was used to examine the surface morphology of skin samples, which showed that the skin structure changed greatly under the treatment of ultrasound and UCA. The present work suggests that, for TDD applications(e.g., nanoparticle drug carriers, transdermal patches and cosmetics), protocols and methods presented in this paper are potentially useful. 相似文献
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选取医学基础化学课程中的2个章节,组织PBL-TBL-CBL组和LBL组进行教学实验,通过成绩考核、教师评价和问卷调查进行教学效果评价,探讨PBL-TBL-CBL整合模式在医学基础化学课程中理论和实验教学上的应用。通过对比分析,证实PBL-TBL-CBL整合模式教学可以充分调动学生的积极主动性,增强自学和团队合作能力,提高实验操作技能,准确掌握教学大纲要求的知识点,提升学生对化学学习的乐趣和自信。建议对基础化学的部分章节采用PBL-TBL-CBL整合模式教学,同时结合LBL传统教学共同来完成大纲要求的教学任务。 相似文献
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利用扫描电镜观察710 mm~2碳纤维复合芯导线(ACCC)过滑车试验后股线的磨损形貌,分析滑车底径对股线损伤的影响及股线损伤机制.同时,考虑股线间的接触与摩擦行为,建立导线全尺寸模型进行导线过滑车非线性动力学有限元分析.试验结果表明:导线过滑车后股线出现塑性变形与磨损,在股线表面初始磨损处以黏着磨损的形式扩展,且股线损伤随滑车底径的增大有所改善;数值分析表明:股线等效塑性应变与摩擦能量损耗开始于导线过滑车时的弯曲过程,且随滑车底径增大而减小,股线损伤的模拟结果与试验情况吻合.在此基础上,研究股线间摩擦系数对股线损伤影响,得到股线损伤随摩擦系数的减小而减小.研究初步认为滑车底径为30倍导线直径时股线损伤在可接受范围内. 相似文献
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利用内源荧光、1-苯氨基萘-8-磺酸(ANS)荧光、远紫外-圆二色光谱以及酶活力测定等手段研究了精氨酸激酶在1,1,1,3,3,3-六氟异丙醇(HFIP)溶液中变性后结构与活性的变化.为避免蛋白质聚沉的出现,实验中采用的变性剂浓度低于8%.当六氟异丙醇浓度为0.5%~1.5%时,蛋白质的二级结构和内源荧光发射峰位都没有发生明显的变化,而外源ANS荧光强度则显著增强.继续提高变性剂浓度至6%后,内源荧光发射峰位明显红移、二级结构含量增大、外源荧光减弱、酶活力完全丧失.内源荧光和外源ANS荧光的变化证明:在0.5%~1.5%六氟异丙醇浓度范围内,蛋白质分子以一种结构相对稳定并类似于天然蛋白结构的熔球态中间体的状态存在.这种熔球态中间体也是精氨酸激酶在去折叠过程中出现的一个平衡态中间体. 相似文献
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富硒蛹虫草的抗氧化活性研究 总被引:1,自引:0,他引:1
采用现代分离技术从富硒蛹虫草中提取硒多糖,然后以苯酚-硫酸法、电感耦合等离子体质谱(ICP—MS)法对硒多糖中多糖含量和硒含量进行测定;在Fenton体系的最佳实验条件下,研究了硒多糖对羟自由基的清除作用及硒多糖对支撑磷脂双层膜(Supported Bilayer Lipid Membranes,s—BLM)的保护作用。结果表明:硒多糖清除羟自由基的效果比与之相同浓度的无机硒、多糖都要明显。其中硒多糖对羟自由基的最高清除率可达38.02%,硒多糖具有很强的抗脂质过氧化、保护支撑磷脂双层膜的作用。 相似文献
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利用kHz激光与固体靶相互作用产生了平均流强为1.3×107 photons·sr-1·s-1的X射线源, 研究了激光的对比度和能量对激光与固体靶相互作用产生的X射线能谱及Kα 产额的影响, 使用刀边成像技术测量了X射线源的源尺寸, 并进行了初步的成像实验. 实验中观察到对于非相对论级别的激光脉冲, 降低激光的对比度有利于提高Kα 产额, 而使用高对比度高强度激光, 更有利于获得高通量高信噪比X射线源.
关键词:
kHz激光
固体靶
X射线 相似文献