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861.
J. L. John 《Cellular and molecular life sciences : CMLS》1994,50(Z1):15-22
Despite being a major organ of the immune system, the spleen's role in resisting, controlling or simply ameliorating nematode infections has been neglected. A review of both filarial and gastrointestinal nematodes suggests that though it is difficult to fully assess or quantify the organ's importance in vivo, the spleen is prominent in acting against nematode parasites in mammals. One manifestation of this is that transfer of lymphocytes from the spleen of immunised individuals can protect recipients against the disease. Expansion of splenic lymphoid tissue also alludes to its activity during nematode infection. There is a considerable need for investigation of the spleen under natural conditions as well as much more rigorously controlled experiments even in mammals besides birds and other vertebrates. 相似文献
862.
In colour measurement ralated industry, reflectance spectrophotometer is the one of the popular measuring machine for measuring colour and quality control. Colour communications is frequently confusing. This is because the colour appearance is subject to the influence of at least three different phenomena: the light source, the object and the visual system. The variation in either the radiant quantity or the spectral distribution of the source can alter the observed colour. Because of this reason, the objective quantitative tool, colour measurement equipment and communication method; become more important in evaluating of the colour. In fact, based on the advanced in computer system and electronic device, the colour measurement becomes more and more accuracy, especially in spectrophotometer measurement. In this paper, we will focus on the review of modern spectrophotometers in coloration industries. 相似文献
863.
Prediction of central nervous system embryonal tumour outcome based on gene expression. 总被引:75,自引:0,他引:75
Scott L Pomeroy Pablo Tamayo Michelle Gaasenbeek Lisa M Sturla Michael Angelo Margaret E McLaughlin John Y H Kim Liliana C Goumnerova Peter M Black Ching Lau Jeffrey C Allen David Zagzag James M Olson Tom Curran Cynthia Wetmore Jaclyn A Biegel Tomaso Poggio Shayan Mukherjee Ryan Rifkin Andrea Califano Gustavo Stolovitzky David N Louis Jill P Mesirov Eric S Lander Todd R Golub 《Nature》2002,415(6870):436-442
Embryonal tumours of the central nervous system (CNS) represent a heterogeneous group of tumours about which little is known biologically, and whose diagnosis, on the basis of morphologic appearance alone, is controversial. Medulloblastomas, for example, are the most common malignant brain tumour of childhood, but their pathogenesis is unknown, their relationship to other embryonal CNS tumours is debated, and patients' response to therapy is difficult to predict. We approached these problems by developing a classification system based on DNA microarray gene expression data derived from 99 patient samples. Here we demonstrate that medulloblastomas are molecularly distinct from other brain tumours including primitive neuroectodermal tumours (PNETs), atypical teratoid/rhabdoid tumours (AT/RTs) and malignant gliomas. Previously unrecognized evidence supporting the derivation of medulloblastomas from cerebellar granule cells through activation of the Sonic Hedgehog (SHH) pathway was also revealed. We show further that the clinical outcome of children with medulloblastomas is highly predictable on the basis of the gene expression profiles of their tumours at diagnosis. 相似文献
864.
M. C. Jackson 《Systemic Practice and Action Research》1990,3(4):357-364
This paper unpeels two influential contributions to modern systems thinking, Beer's viable system model (VSM) and Checkland's soft systems methodology (SSM), and finds inside a critical kernel. It is argued, indeed, that these approaches become coherent only when liberated from their regulative shells and interpreted from the critical position. So much does the critical kernel lie at the very heart of modern systems thinking. 相似文献
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Presented are estimates of demand equations and producer revenue projections for rural farm electricity consumers in the USA. Statistical tests include a Box-Cox comparison of functional form, a Koyck-distributed lag, and a contrast of average versus marginal prices. Producer revenue projections take account of the estimated demand equation and non-continuous rate schedules for each of the electricity distributors. Multiple price equilibria result from differences in administered price schedules between sellers. The ‘effective’ price elasticity based upon forecasts which take account of the market circumstances is lower than the simple demand point elasticity but higher than found in some previous studies. 相似文献
867.
从我开始能够阅读有关科学内容书籍的时候起,我就希望将来可以成为一名科学家。由于对数学方面有着特殊的爱好,使我最终转向了理论物理学的学习。研究金属电子的性质听起来有些平常,但这是真事。事实上要进行这方面的研究,对量子理论知识有着很高的要求,因此我始终将这些原理当作从未被发 相似文献
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