418 research outputs found
Hepatocyte growth factor (HGF) receptor expression is inducible and is part of the delayed-early response to HGF.
The c-MET proto-oncogene encodes the tyrosine kinase receptor for hepatocyte growth factor (HGF), also known as scatter factor, a potent mitogen and motogen for epithelial cells. The level of the HGF receptor expressed by epithelial cells varies in different growth conditions, being lower in growth arrested confluent monolayers and higher in growing sparse cells. The amount of HGF receptor mRNA increases from 3- to 5-fold after stimulation of confluent monolayers by serum and up to 10-fold after stimulation of protein kinase C by 12-O-tetradecanoylphorbol-13-acetate (TPA). An increased level of the receptor mRNA was also observed after cell stimulation with nanomolar concentration of HGF itself. The effect was transient, dose, and time-dependent. Transcription of a reporter gene under control of the cloned 297 base pair c-MET promoter was also stimulated by serum, TPA, or HGF. The accumulation of specific mRNA is followed by appearance of the HGF receptor precursor protein, which is further processed to the receptor mature form. After HGF stimulation, HGF receptor expression follows c-FOS and c-JUN induction with a peak approximately 4 h. Pretreatment with the protein synthesis inhibitor puromycin strongly reduced the response to HGF, while cycloheximide alone increased the level of the receptor mRNA. These data show that c-MET behaves as a delayed early-response gene and suggest that the HGF response is autoamplified by inducing the specific receptor
Complete determination of neutron yield from 62 MeV protons on 9Be for the design of a low – power ADS
Within the European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics of future fast neutron-based reactors are very important. In this respect, an Accelerator Driven System low-power prototype, based on a 70 MeV proton beam impinging on a thick Beryllium converter, was recently proposed and designed within the INFN-E project. The world data on neutron yield from Be target are scarce in this proton energy range. This lack of data calls for a dedicated measurement which was performed at INFN Laboratori Nazionali del Sud, covering a wide angular range, from 0 to 150 degrees, and an almost complete neutron energy interval, from thermal up to the beam energy. In this contribution the results are discussed together with the description of the proposed ADS facility
Study of an intrinsically safe infrastructure for training and research on nuclear technologies
Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will illustrate the conceptual design of an Accelerator-Driven System with high safety standards, but ample flexibility for measurements. The design assumes as base option a 70MeV, 0.75mA proton cyclotron, as the one which will be installed at the INFN National Laboratory in Legnaro, Italy and a Beryllium target, with Helium gas as core coolant.
Safety is guaranteed by limiting the thermal power to 200 kW, with a neutron multiplication coefficient around 0.94, loading the core with fuel containing Uranium enriched at 20% inserted in a solid-lead diffuser. The small decay heat can be passively removed by thermal radiation from the vessel. Such a system could be used to study, among others, some specific aspects of neutron diffusion in lead, beam-core coupling, target cooling and could serve as a training facility
Delle opere di M. Giovanni Boccacci ... Il Filocopo ; volume II.
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Delle opere di M. Giovanni Boccacci ... L'ameto o ver Commedia delle ninfe fiorentine ; volume IV.
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Delle opere di M. Giovanni Boccacci ... Il comento sopra la Commedia di Dante Alighieri
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