排序方式: 共有23条查询结果,搜索用时 0 毫秒
1.
The spacecraft Voyager 1 is at a distance greater than 85 au from the Sun, in the vicinity of the termination shock that marks the abrupt slowing of the supersonic solar wind and the beginning of the extended and unexplored distant heliosphere. This shock is expected to accelerate 'anomalous cosmic rays', as well as to re-accelerate Galactic cosmic rays and low-energy particles from the inner Solar System. Here we report a significant increase in the numbers of energetic ions and electrons that persisted for seven months beginning in mid-2002. This increase differs from any previously observed in that there was a simultaneous increase in Galactic cosmic ray ions and electrons, anomalous cosmic rays and low-energy ions. The low-intensity level and spectral energy distribution of the anomalous cosmic rays, however, indicates that Voyager 1 still has not reached the termination shock. Rather, the observed increase is an expected precursor event. We argue that the radial anisotropy of the cosmic rays is expected to be small in the foreshock region, as is observed. 相似文献
2.
Facciabene A Peng X Hagemann IS Balint K Barchetti A Wang LP Gimotty PA Gilks CB Lal P Zhang L Coukos G 《Nature》2011,475(7355):226-230
Although immune mechanisms can suppress tumour growth, tumours establish potent, overlapping mechanisms that mediate immune evasion. Emerging evidence suggests a link between angiogenesis and the tolerance of tumours to immune mechanisms. Hypoxia, a condition that is known to drive angiogenesis in tumours, results in the release of damage-associated pattern molecules, which can trigger the rejection of tumours by the immune system. Thus, the counter-activation of tolerance mechanisms at the site of tumour hypoxia would be a crucial condition for maintaining the immunological escape of tumours. However, a direct link between tumour hypoxia and tolerance through the recruitment of regulatory cells has not been established. We proposed that tumour hypoxia induces the expression of chemotactic factors that promote tolerance. Here we show that tumour hypoxia promotes the recruitment of regulatory T (T(reg)) cells through induction of expression of the chemokine CC-chemokine ligand 28 (CCL28), which, in turn, promotes tumour tolerance and angiogenesis. Thus, peripheral immune tolerance and angiogenesis programs are closely connected and cooperate to sustain tumour growth. 相似文献
3.
4.
Zusammenfassung Die bengalische «Gram»-Pflanze (Cicer arietinum L.) ist in Samenschale, Cotyledonen und Restteile des Embryos zerlegt worden. In diesen Fragmenten wurde die Verteilung von Protein, Extraktstoffen, Asche, Faseranteilen sowie Calzium, Phosphor und Eisen näher untersucht. In den relativ massiven Samenschalen fand sich auffallend viel Calcium, während die übrigen untersuchten Stoffe in den andern Pflanzenteilen (mit Ausnahme vom Faseranteil) nur geringfügig vorhanden waren. Die Cotyledonen, die mehr als 85% dieses Getreides ausmachen, zeigen chemisch ausgeglichene Verhältnisse. 相似文献
5.
6.
O. P. Lal 《Cellular and molecular life sciences : CMLS》1972,28(6):717-718
Zusammenfassung Nachweis, dass Piperonylbutoxid (0,2%) in Kombination mit Terramycin (0,2%) und dem Emulgator NP10 (0,1%) die Larvalentwicklung verlangsamt und sowohl das Gewicht wie die Reproduktionsfähigkeit der resultierenden Adulten vonAphis fabae reduziert. Durch Zugabe des allein unwirksamen Piperonylbutoxyds werden diese Effekte gesteigert.
I express my sincere thanks to Professor Dr.H. Schmutterer, Giessen University, West Germany, for advice and encouragement, and to the German Academic Exchange Service for the financial assistance. 相似文献
I express my sincere thanks to Professor Dr.H. Schmutterer, Giessen University, West Germany, for advice and encouragement, and to the German Academic Exchange Service for the financial assistance. 相似文献
7.
A reduction in volume and free and total acidity of gastric content was noted along with reduction in ulcer index, with a shift of the site of ulceration from fundus to the glandular part of the stomach, following vagotomy in pylorus-ligated rats. Low volume and acidity explains the absence of ulcers in the fundus, but the increased involvement of glandular part in ulceration is possibly due to weakening of the mucosal barrier following vagotomy. 相似文献
8.
Zusammenfassung InCassia occidentalis Linn. wurde das 1-Glukosid des 3-Methyl-6-methoxy-1,8-dihydroxy-anthrachinons nachgewiesen.
The author thanks the C.S.I.R., New Delhi, India, for financial assistance. 相似文献
The author thanks the C.S.I.R., New Delhi, India, for financial assistance. 相似文献
9.
10.