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491.
The difference in the index of refraction between the receptor outer segment and the interstitial matrix has been determined to be 0.06 by making use of the waveguide properties of rat rod photoreceptors. This was done by determining the cutoff wavelength for the transition between the bilobe or annulus modal patterns and the single-lobe H E 11 modal pattern, and by measuring the diameter of the transmitting cell. These measurements were made on bleached receptors. Enoch, Scandrett, and Tobey had previously shown that bleaching only slightly alters the outer-segment index of refraction and diameter in the frog. Assuming interspecies transfer, and using Sidman's prior estimate of bleached rat rod outer-segment index of refraction, then the index of refraction of the interstitial matrix of the albino rat is estimated to be 1.3476. This estimate was made using two different media in contact with the retinal preparation, a miscible mountant tissue culture medium believed to be compatible with the rat retina, and an encapsulating nonmiscible silicone oil which allows only ocular media from the same eye in contact with the outer segments. 相似文献
492.
W.FL 《军民两用技术与产品》2007,(1):5
从国务院国资委获悉,《关于推进国有资本调整和国有企业重组的指导意见》出台十项措施促进国企改革重组,并明确到2010年中央企业调整重组至80到100户。 相似文献
493.
The HPV proteins encoded by the early viral genes, including E6 and E7, are thought to subvert the normal regulatory pathways of infected cells to accommodate viral replication. Mechanistically some of this is accomplished by protein-protein interactions between viral proteins and a number of key cellular regulatory proteins that include tumor suppressor gene products. By undermining cellular regulatory pathways the HPV oncogenes cause hyperproliferation and the perturbation of normal cellular differentiation pathways. Although expression of the high-risk HPV-encoded E6 and E7 oncoproteins may be important prerequisites for cellular transformation, it is very likely that additional cellular changes are necessary for carcinogenic progression. The elucidation of the role of the early HPV genes in the initiation and/or maintenance of carcinogenic progression will continue to be a fascinating area of investigation and may reveal new opportunities for antiviral therapy and antitumor intervention. 相似文献