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41.
Modern high-power lasers can generate extreme states of matter that are relevant to astrophysics, equation-of-state studies and fusion energy research. Laser-driven implosions of spherical polymer shells have, for example, achieved an increase in density of 1,000 times relative to the solid state. These densities are large enough to enable controlled fusion, but to achieve energy gain a small volume of compressed fuel (known as the 'spark') must be heated to temperatures of about 108 K (corresponding to thermal energies in excess of 10 keV). In the conventional approach to controlled fusion, the spark is both produced and heated by accurately timed shock waves, but this process requires both precise implosion symmetry and a very large drive energy. In principle, these requirements can be significantly relaxed by performing the compression and fast heating separately; however, this 'fast ignitor' approach also suffers drawbacks, such as propagation losses and deflection of the ultra-intense laser pulse by the plasma surrounding the compressed fuel. Here we employ a new compression geometry that eliminates these problems; we combine production of compressed matter in a laser-driven implosion with picosecond-fast heating by a laser pulse timed to coincide with the peak compression. Our approach therefore permits efficient compression and heating to be carried out simultaneously, providing a route to efficient fusion energy production.  相似文献   
42.
Columns for visual features of objects in monkey inferotemporal cortex.   总被引:21,自引:0,他引:21  
I Fujita  K Tanaka  M Ito  K Cheng 《Nature》1992,360(6402):343-346
At early stages of the mammalian visual cortex, neurons with similar stimulus selectivities are vertically arrayed through the thickness of the cortical sheet and clustered in patches or bands across the surface. This organization, referred to as a 'column', has been found with respect to one-dimensional stimulus parameters such as orientation of stimulus contours, eye dominance of visual inputs, and direction of stimulus motion. It is unclear, however, whether information with extremely high dimensions, such as visual shape, is organized in a similar columnar fashion or in a different manner in the brain. Here we report that the anterior inferotemporal area of the monkey cortex, the final station of the visual cortical stream crucial for object recognition, consists of columns, each containing cells responsive to similar visual features of objects.  相似文献   
43.
Summary A significant antitumor activity of oridonin (1) and lasiokaurin (2), the kaurene-type diterpenoids ofIsodon species, was shown by their i.p. injection to the test mice inoculated by Ehrlich ascites carcinoma. Enmein (8), compounds9 and3 were also active under larger dose. Subsequently, the relationship between their chemical structure and antitumor activity was investigated, and the activity of oridonin (1) and lasiokaurin (2) was rationalized in terms of their structural feature.  相似文献   
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J Fujita  O Yoshida  Y Yuasa  J S Rhim  M Hatanaka  S A Aaronson 《Nature》1984,309(5967):464-466
DNA-mediated gene transfer (transfection) studies using NIH 3T3 cells as recipients have demonstrated the presence of transforming genes (oncogenes) in diverse human tumours. A large proportion of oncogenes so far detected by DNA transfection are related to the Ha-ras onc gene of Harvey (and BALB) murine sarcoma viruses (MSV), Ki-ras, the oncogene of Kirsten MSV, and a third member of the ras gene family, N-ras. Individual tumours of many different organs have been associated with the activation of members of the ras gene family. We now present the first systematic survey of human urinary tract tumours processed immediately after surgery, as well as normal tissues from the same patients, to detect the presence of such genes. We demonstrate activation of Ha-ras as an oncogene in around 10% of randomly selected urinary tract tumours as well as direct evidence that oncogene activation is the result of a somatic event which is selected for within the tumour cell population.  相似文献   
46.
Systems for protein degradation are essential for tight control of the inflammatory immune response. Autophagy, a bulk degradation system that delivers cytoplasmic constituents into autolysosomes, controls degradation of long-lived proteins, insoluble protein aggregates and invading microbes, and is suggested to be involved in the regulation of inflammation. However, the mechanism underlying the regulation of inflammatory response by autophagy is poorly understood. Here we show that Atg16L1 (autophagy-related 16-like 1), which is implicated in Crohn's disease, regulates endotoxin-induced inflammasome activation in mice. Atg16L1-deficiency disrupts the recruitment of the Atg12-Atg5 conjugate to the isolation membrane, resulting in a loss of microtubule-associated protein 1 light chain 3 (LC3) conjugation to phosphatidylethanolamine. Consequently, both autophagosome formation and degradation of long-lived proteins are severely impaired in Atg16L1-deficient cells. Following stimulation with lipopolysaccharide, a ligand for Toll-like receptor 4 (refs 8, 9), Atg16L1-deficient macrophages produce high amounts of the inflammatory cytokines IL-1beta and IL-18. In lipopolysaccharide-stimulated macrophages, Atg16L1-deficiency causes Toll/IL-1 receptor domain-containing adaptor inducing IFN-beta (TRIF)-dependent activation of caspase-1, leading to increased production of IL-1beta. Mice lacking Atg16L1 in haematopoietic cells are highly susceptible to dextran sulphate sodium-induced acute colitis, which is alleviated by injection of anti-IL-1beta and IL-18 antibodies, indicating the importance of Atg16L1 in the suppression of intestinal inflammation. These results demonstrate that Atg16L1 is an essential component of the autophagic machinery responsible for control of the endotoxin-induced inflammatory immune response.  相似文献   
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48.
We found that aloe extract contains a lectin-like substance which reacts with serum proteins of various animals. Furthermore, in human serum 2 proteins, alpha2-macroglobulin and alpha1-antitrypsin, were shown to be reactive with aloe extract.  相似文献   
49.
Summary The amount of tyrosine hydroxylase protein in the adrenal medulla, which was estimated by a quantitative immunofluorescence method, was higher in spontaneously hypertensive rats than in normotensive control Wistar-Kyoto rats at 4 and 16 weeks of age before and after the development of hypertension.This study was supported by grants from the Ministry of Education, Science and Culture, Japan (No. 59570018). Reprint requests to I.N., Department of Anatomy, School of Medicine, Fujita-Gakuen Health University, Toyoake, Aichi 470-11 (Japan).  相似文献   
50.
The amount of tyrosine hydroxylase protein in the adrenal medulla, which was estimated by a quantitative immunofluorescence method, was higher in spontaneously hypertensive rats than in normotensive control Wistar-Kyoto rats at 4 and 16 weeks of age before and after the development of hypertension.  相似文献   
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