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Zusammenfassung Die Fliessgeschwindigkeit der Lymphe im ductus thoracicus und der Gehalt an Phospholipiden, Cholesterin und Triglyceriden wurde vor und nach akutem Blutverlust in anaesthesierten, splenektomierten Hunden bestimmt. Vor allem nach grossen Blutverlusten wurde eine starke Erhöhung des Lipidgehaltes der Lymphe nachgewiesen. 相似文献
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Nanotechnology: high-speed integrated nanowire circuits 总被引:1,自引:0,他引:1
Macroelectronic circuits made on substrates of glass or plastic could one day make computing devices ubiquitous owing to their light weight, flexibility and low cost. But these substrates deform at high temperatures so, until now, only semiconductors such as organics and amorphous silicon could be used, leading to poor performance. Here we present the use of low-temperature processes to integrate high-performance multi-nanowire transistors into logical inverters and fast ring oscillators on glass substrates. As well as potentially enabling powerful electronics to permeate all aspects of modern life, this advance could find application in devices such as low-cost radio-frequency tags and fully integrated high-refresh-rate displays. 相似文献
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Correction of feline arylsulphatase B deficiency (mucopolysaccharidosis VI) by bone marrow transplantation 总被引:3,自引:0,他引:3
P W Gasper M A Thrall D A Wenger D W Macy L Ham R E Dornsife K McBiles S L Quackenbush M L Kesel E L Gillette 《Nature》1984,312(5993):467-469
Feline and human mucopolysaccharidosis VI (MPS VI or Maroteaux-Lamy syndrome) are inherited autosomal recessive deficiencies of lysosomal enzyme arylsulphatase B. Affected cats and children exhibit lesions caused by incompetent degradation, retinal atrophy and excessive urinary excretion of dermatan facial dysmorphia, corneal stromal opacities, leukocyte granulation, retinal atrophy and excessive urinary excretion of dermatan sulphate--and usually die before adulthood. Most attempts to treat humans affected with MPS VI or other mucopolysaccharidoses have been ineffective or logistically prohibitive, but allogeneic bone marrow transplantation (BMT) offers promise for cure of certain inborn errors of metabolism. Engraftment of normal donor marrow may endow the enzyme-deficient recipient with a continuous source of enzyme-competent blood cells and tissue macrophages to facilitate degradation of stored substrate and to prevent genesis of further malformations. To test this hypothesis, we performed allogeneic BMT in a 2-year-old male Siamese cat with advanced MPS VI. Here we describe BMT-induced correction of this hereditary enzyme deficiency. 相似文献
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从弹性理论和波动理论出发,推导出考虑阻尼的旋转盘形锥齿轮波动振动响应的模态解。得到波动共振和倍频共振转速的计算公式。最后给出计算和实测的比较。 相似文献
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Metamaterials with negative refractive indices can manipulate electromagnetic waves in unusual ways, and can be used to achieve, for example, sub-diffraction-limit focusing, the bending of light in the 'wrong' direction, and reversed Doppler and Cerenkov effects. These counterintuitive and technologically useful behaviours have spurred considerable efforts to synthesize a broad array of negative-index metamaterials with engineered electric, magnetic or optical properties. Here we demonstrate another route to negative refraction by exploiting the inertia of electrons in semiconductor two-dimensional electron gases, collectively accelerated by electromagnetic waves according to Newton's second law of motion, where this acceleration effect manifests as kinetic inductance. Using kinetic inductance to attain negative refraction was theoretically proposed for three-dimensional metallic nanoparticles and seen experimentally with surface plasmons on the surface of a three-dimensional metal. The two-dimensional electron gas that we use at cryogenic temperatures has a larger kinetic inductance than three-dimensional metals, leading to extraordinarily strong negative refraction at gigahertz frequencies, with an index as large as -700. This pronounced negative refractive index and the corresponding reduction in the effective wavelength opens a path to miniaturization in the science and technology of negative refraction. 相似文献
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Ro DK Paradise EM Ouellet M Fisher KJ Newman KL Ndungu JM Ho KA Eachus RA Ham TS Kirby J Chang MC Withers ST Shiba Y Sarpong R Keasling JD 《Nature》2006,440(7086):940-943
Malaria is a global health problem that threatens 300-500 million people and kills more than one million people annually. Disease control is hampered by the occurrence of multi-drug-resistant strains of the malaria parasite Plasmodium falciparum. Synthetic antimalarial drugs and malarial vaccines are currently being developed, but their efficacy against malaria awaits rigorous clinical testing. Artemisinin, a sesquiterpene lactone endoperoxide extracted from Artemisia annua L (family Asteraceae; commonly known as sweet wormwood), is highly effective against multi-drug-resistant Plasmodium spp., but is in short supply and unaffordable to most malaria sufferers. Although total synthesis of artemisinin is difficult and costly, the semi-synthesis of artemisinin or any derivative from microbially sourced artemisinic acid, its immediate precursor, could be a cost-effective, environmentally friendly, high-quality and reliable source of artemisinin. Here we report the engineering of Saccharomyces cerevisiae to produce high titres (up to 100 mg l(-1)) of artemisinic acid using an engineered mevalonate pathway, amorphadiene synthase, and a novel cytochrome P450 monooxygenase (CYP71AV1) from A. annua that performs a three-step oxidation of amorpha-4,11-diene to artemisinic acid. The synthesized artemisinic acid is transported out and retained on the outside of the engineered yeast, meaning that a simple and inexpensive purification process can be used to obtain the desired product. Although the engineered yeast is already capable of producing artemisinic acid at a significantly higher specific productivity than A. annua, yield optimization and industrial scale-up will be required to raise artemisinic acid production to a level high enough to reduce artemisinin combination therapies to significantly below their current prices. 相似文献
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