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Zusammenfassung Immunologische Toleranz konnte in Mäusen durch hohe Dosen vonE. coli Lipopolysaccharid erreicht werden. Der Effekt war mit Hilfe der passiven hämolytischen «plaque»-Methode besser zu erfassen als im direkten bakteriologischen System.

Supported in part by grants from the U.S. National Science Foundation and the National Institutes of Health, Bethesda, Maryland.  相似文献   
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Peripartum cardiomyopathy (PPCM) is an often fatal disease that affects pregnant women who are near delivery, and it occurs more frequently in women with pre-eclampsia and/or multiple gestation. The aetiology of PPCM, and why it is associated with pre-eclampsia, remain unknown. Here we show that PPCM is associated with a systemic angiogenic imbalance, accentuated by pre-eclampsia. Mice that lack cardiac PGC-1α, a powerful regulator of angiogenesis, develop profound PPCM. Importantly, the PPCM is entirely rescued by pro-angiogenic therapies. In humans, the placenta in late gestation secretes VEGF inhibitors like soluble FLT1 (sFLT1), and this is accentuated by multiple gestation and pre-eclampsia. This anti-angiogenic environment is accompanied by subclinical cardiac dysfunction, the extent of which correlates with circulating levels of sFLT1. Exogenous sFLT1 alone caused diastolic dysfunction in wild-type mice, and profound systolic dysfunction in mice lacking cardiac PGC-1α. Finally, plasma samples from women with PPCM contained abnormally high levels of sFLT1. These data indicate that PPCM is mainly a vascular disease, caused by excess anti-angiogenic signalling in the peripartum period. The data also explain how late pregnancy poses a threat to cardiac homeostasis, and why pre-eclampsia and multiple gestation are important risk factors for the development of PPCM.  相似文献   
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本文讨论利用三类纳米材料对癌症进行诊断和治疗(简称诊治学)。这三类材料包含纳米金属、过渡金属氧化物和金属有机配合物,它们可通过化学湿法来制备。纳米技术具有精确构建细小材料的优越性,所以纳米材料被用来从细胞和基因水平上靶向攻击癌细胞,其精确度高、副作用小。目前的挑战在于对转移性癌症、抗药性癌症和肿瘤干细胞的治疗,通过有效设计作为载体的纳米材料,可以实现药物定向传递,进而实现对成体干细胞、胸腺T细胞的免疫治疗。作者讨论了上述纳米材料以及它们在癌症诊治中的应用,重点讨论了纳米材料的湿化学合成、性能及应用,该类材料具有独特的拓扑结构和孔隙度,因而具有高效靶向药物输送功能。另外,该类材料(特别是金属有机配合物)具有可调的颗粒大小、形状及组成,在靶向癌症治疗中,显示出循环半衰期长的优点。该文也就材料对肿瘤的诊治效率及纳米材料运作机制进行了探讨,以期克服目前所使用纳米材料的局限性。  相似文献   
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简述了近期能源的发展动向,特别以氢能源为重点,就产氢、储氢及利用氢三个方面进行阐述。氢气作为高能量密度的燃料载体在提供能量的过程中可实现或接近实现无碳排放。作者及团队发现,将分散式电解水产氢技术应用在燃料电池模型汽车上,模型车的运行速度及里程可提高30%以上。  相似文献   
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利用人工神经网络对化学传感器的晶格畸变进行了深入研究.实验结果表明:传感原件钙掺杂钛酸铅薄膜材料随合成参数的变化而呈现不同的晶格畸变度,该参数通过X射线粉末衍射精细结构确定,并作为人工神经网络的输出变量;合成参数作为输入变量,以MatlabTM作为操作平台,利用三层识别方法对传感元件的纳米结构进行评估与预测.实验结果与...  相似文献   
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应用两亲软化学法,将纳米铂有效地分散在多层碳纳米管阵列(ACNT)表面,使其得以修饰,形成了高活性的阴极催化材料,用于制备结构膜阴极组合件(MEA)。对MEA进行的形态学和电化学测试,证明可以大大改善质子交换膜燃料电池(PEMFC)的纳米结构和电化学性能。该种阴极催化材料除了表面均匀及高活性之外,还表现出比目前设计出的PEMFC高出约6倍的输出功率,在一定电位下的氧气中可以达到900 mW·cm-2,而贵金属铂搭载量则显著降低至0.14~0.19 mg·cm-2。实验结果表明,由于碳纳米管阵列的厌水性保证了电极性能的稳定性,从而为提高PEMFC电池的长期稳定性及降低成本提供了一条新的解决思路,具有一定的学术研究价值和经济应用价值。  相似文献   
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Environmental tobacco smoke (ETS) is a well- known reason of many adverse health consequences in pregnant women. Exposure of ETS during pregnancy may increase the risk of some fetal diseases in pregnant women and/or birth defects in neonates. Many countries have implemented laws to control smoking and free of second hand smoke in all enclosed workplaces. In China, anti- smoking law was enforced in March 2010. We aimed to assess the exposure of pregnant women to cotinine after anti-smoking law was implemented in China. The urine samples were collected from 2,100 volunteers from Zhejiang Province, China and urinary concentration of cotinine was measured using gas chromatography and mass spectrometry. Cotinine was detected in 87 % of the pregnant women. The GM and 95th percentile concentration in pregnant women were 4.28 and 44.00 μg/L, respectively. Similarly, the GM and 95th concentration of cotinine were significantly higher in smoking group than in non-smoking group (P 〈 0.0001). Our results indicate that pregnant women in China are at the high risk of exposure ETS. Further attempts are required to make strategies to find out the sources of ETS exposure and prevent smoking at public places especially during pregnancy.  相似文献   
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