Toll-like receptor 4-dependent activation of dendritic cells by beta-defensin 2   总被引：1，自引：0，他引：1  

Biragyn A  Ruffini PA  Leifer CA  Klyushnenkova E  Shakhov A  Chertov O  Shirakawa AK  Farber JM  Segal DM  Oppenheim JJ  Kwak LW 《Science (New York, N.Y.)》2002,298(5595):1025-1029

beta-Defensins are small antimicrobial peptides of the innate immune system produced in response to microbial infection of mucosal tissue and skin. We demonstrate that murine beta-defensin 2 (mDF2beta) acts directly on immature dendritic cells as an endogenous ligand for Toll-like receptor 4 (TLR-4), inducing up-regulation of costimulatory molecules and dendritic cell maturation. These events, in turn, trigger robust, type 1 polarized adaptive immune responses in vivo, suggesting that mDF2beta may play an important role in immunosurveillance against pathogens and, possibly, self antigens or tumor antigens.  相似文献   

Early local last glacial maximum in the tropical Andes   总被引：1，自引：0，他引：1  

Smith JA  Seltzer GO  Farber DL  Rodbell DT  Finkel RC 《Science (New York, N.Y.)》2005,308(5722):678-681

The local last glacial maximum in the tropical Andes was earlier and less extensive than previously thought, based on 106 cosmogenic ages (from beryllium-10 dating) from moraines in Peru and Bolivia. Glaciers reached their greatest extent in the last glacial cycle approximately 34,000 years before the present and were retreating by approximately 21,000 years before the present, implying that tropical controls on ice volumes were asynchronous with those in the Northern Hemisphere. Our estimates of snowline depression reflect about half the temperature change indicated by previous widely cited figures, which helps resolve the discrepancy between estimates of terrestrial and marine temperature depression during the last glacial cycle.  相似文献   

The convergence of computing and telecommunications systems     

Farber D  Baran P 《Science (New York, N.Y.)》1977,195(4283):1166-1170

Since we do not know of any completely workable solutions to the problems we have considered, we shall settle for a few general observations: 1) The public availability of socially useful computer communications services is and has been held back by legal battles that are now under way between the potential suppliers. 2) No simple resolution of these issues in the near future seems likely in view of the past conceptual separation of computers and communications doctrines. 3) The current policy is to determine whether the nation shall or shall not have certain computer communications services, by the adversary process. In this process, often only the voices of the loudest adversary suppliers are heard. 4) Although there can be no certainty that better alternatives cannot be devised, we believe that such a possibility assumes a higher probability if the key actors come from the technical community sectors more representative of the future consumers. 5) If we are to have the new services that are possible, we need an approach that makes better use of the technologists' dreams and goals rather than have future prospects excessively bound by lawyers paid to preserve the interests of their clients, irrespective of any secondary consequences. 6) We cannot be sanguine about this possibility, as technological statesmanship is too easily corrupted by the same forces that have placed us in this predicament. Furthermore, even if not corrupted, beneficial cooperation can too readily be regarded as simply collusion. 7) Although we do not have any clear answer, we do know that present approaches are not taking us where we want to go very rapidly and that alternative approaches should at least be considered.  相似文献   

Local dispersal of Puccinia striiformis f. sp. tritici from isolated source lesions          下载免费PDF全文

D. H. Farber  J. Medlock  C. C. Mundt 《Plant pathology》2017,66(1):28-37

Understanding how disease foci arise from single source lesions has not been well studied. Here, single wheat leaves were inoculated with Puccinia striiformis f. sp. tritici urediniospores, and all wheat leaves within two intersecting 0.3 × 3.0 m transects were sampled in eight replicates over 3 years. The lesions observed on each of the top three leaves on plants within 1.5 m from the source lesion were three‐dimensionally mapped. The total number of lesions within a 1.5 m radius was estimated by dividing the number of lesions observed within each 0.025 m‐wide annulus by the fraction of the annulus sampled. The estimated total number of lesions produced within 1.5 m of a single source lesion ranged from 27 to 776, with a mean of 288 lesions. Eighty percent of the lesions were recorded within 0.69 m of the source infection. The proportion of total lesions observed at a given distance from the source was fitted well by the Lomax and Weibull distributions, reflecting the large proportion of lesions arising close to the source, and when fitted by an inverse power distribution had a slope (b) of 2.5. There were more lesions produced on leaves higher in the canopy than on lower leaves, with more lesions being detected above than below the point of inoculation. Simultaneous measurement of lesion gradients and spore dispersal in the final year of the study suggests that this pattern is due to greater susceptibility of upper leaves, rather than increased dispersal to upper leaves.  相似文献