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排序方式: 共有277条查询结果,搜索用时 15 毫秒
81.
Chiara Urbinati Maria Milanesi Nicola Lauro Cinzia Bertelli Guido David Pasqualina DUrsi Marco Rusnati Paola Chiodelli 《Molecules (Basel, Switzerland)》2021,26(24)
HIV-1 transactivating factor Tat is released by infected cells. Extracellular Tat homodimerizes and engages several receptors, including integrins, vascular endothelial growth factor receptor 2 (VEGFR2) and heparan sulfate proteoglycan (HSPG) syndecan-1 expressed on various cells. By means of experimental cell models recapitulating the processes of lymphocyte trans-endothelial migration, here, we demonstrate that upon association with syndecan-1 expressed on lymphocytes, Tat triggers simultaneously the in cis activation of lymphocytes themselves and the in trans activation of endothelial cells (ECs). This “two-way” activation eventually induces lymphocyte adhesion and spreading onto the substrate and vascular endothelial (VE)-cadherin reorganization at the EC junctions, with consequent endothelial permeabilization, leading to an increased extravasation of Tat-presenting lymphocytes. By means of a panel of biochemical activation assays and specific synthetic inhibitors, we demonstrate that during the above-mentioned processes, syndecan-1, integrins, FAK, src and ERK1/2 engagement and activation are needed in the lymphocytes, while VEGFR2, integrin, src and ERK1/2 are needed in the endothelium. In conclusion, the Tat/syndecan-1 complex plays a central role in orchestrating the setup of the various in cis and in trans multimeric complexes at the EC/lymphocyte interface. Thus, by means of computational molecular modelling, docking and dynamics, we also provide a characterization at an atomic level of the binding modes of the Tat/heparin interaction, with heparin herein used as a structural analogue of the heparan sulfate chains of syndecan-1. 相似文献
82.
Simona Bronco Monica Bertoldo Elisa Taburoni Cinzia Cepek Massimo Sancrotti 《Macromolecular Symposia》2004,218(1):71-80
A cold plasma feed with either oxygen or nitrogen was used to modify thin Low Density Polyethylene films. The treatment improved both the surface wettability and the curing kinetic of a polyurethane based adhesive spread on the surface. The chemical functionalities responsible of the observed behaviours were investigated and monitored over time by high resolution x-ray photoelectron spectroscopy. Atomic force microscopy were used to compare the effects of the two feeding gases on the surface morphology of films exposed (to the plasma) for equal times. The effect on the treated films of the atmosphere exposure and of the aging time were also considered. 相似文献
83.
Maulucci N De Riccardis F Botta CB Casapullo A Cressina E Fregonese M Tecilla P Izzo I 《Chemical communications (Cambridge, England)》2005,(10):1354-1356
The synthesis of a new class of amphiphilic calix[4]arene-based ionophores, relying on direct reductive amination as a key step, and the evaluation of their H+ and Na+ transporting properties is described. 相似文献
84.
The northern and southern polar oceans have very different oceanographic features. Taking advantage of the information available on haemoglobin structure and function, we analysed the evolutionary history of the alpha and beta globins of Antarctic and Arctic haemoglobins as a basis for reconstructing the phylogenetic relationships among species. 相似文献
85.
de Pasquale F Testa C Soldaini R Casieri C Podo F De Luca F 《Magnetic resonance imaging》2005,23(4):577-584
We propose an application of a Bayesian methodology to dynamic MR images of protons J-coupled to 13C nuclei for monitoring the in vivo 13C-glucose uptake of mouse brain. The very low population of these protons and the random noise make the analysis of these images extremely difficult. The proposed method restores the images and provides an "activation" map of the mouse brain by means of a hypothesis testing procedure. The restoration step is performed in the Bayesian framework so that among the other advantages of a stochastic approach, it is possible to model spatial and temporal information about neighboring pixels. This leads to a restoration procedure able to reduce the noise level while preserving the information about the edges of signal areas. Based on the restored images, the testing procedure provides us with a reliable map of pixels characterized by the 13C-glucose uptake. 相似文献
86.
Cinzia Bonotto Dr. 《ZDM》2001,33(3):75-84
In this paper we present an explorative study for which special cultural artifacts have been used, i.e. supermarket receipts, to try to construct with 9-year old pupils (fourth class of primary school) a new mathematical knowledge, i.e. the algorithm for multiplication of decimal numbers. Furthermore also estimation and approximation processes have been introduced, procedures that are not commonly used in ordinary teaching activity. In our study the receipts, through some modifications, have become more explicitly tools of mediation and integration between in and out-of school knowledge, so they can be utilized to create new mathematical goals, thus becoming real mathematizing tools and constituting a didactic interface between in and out-of-school mathematics. In agreement with ethnomathematical perspective we deem that it is a task for the teacher to know, in order to be able to profitably take account of the teaching, the life experienced by the pupil. Future mathematics teachers should be prepared a) to see mathematics incorporated into real world, b) to investigate mathematical ideas and practices of their pupils, and c) to look for ways to incorporate into the curriculum elements belonging to the sociocultural environment of the pupils, as a starting point for mathematical activities in the classroom. In this way the motivation, interest and curiosity of the pupils will be increased and the attitude towards mathematics of both pupils and teachers will be changed. 相似文献
87.
Valter Castelvetro Francesco Ciardelli Cinzia De Vita Antonio Puppo 《Macromolecular rapid communications》2006,27(8):619-625
Summary: The synthesis of aqueous dispersions of hybrid acrylic copolymer particles with either a monofunctional or a multifunctional polyhedral oligomeric silsesquioxane methacrylate comonomer has been performed by free radical heterophase polymerization. The miniemulsion process gives stable latexes, whereas the less controlled emulsion route results in colloidal instability of the products. The thermal and mechanical properties of the nanocomposite latex films have been preliminarily investigated.
88.
Summary: A comparative study of the performances of (bpzmp)ZrBz3 ( 1 ) and (hppzm)ZrBz3 ( 2 ) activated with B(C6F5)3 or [Ph3C][B(C6F5)4] in ethylene polymerisation pointed out that the steric properties of the metal complex and the boron activator affect the productivity of the catalyst and, more remarkably, the microstructure of the polyethylenes produced. A polymerisation mechanism accounting for these results has been proposed.
89.
Starting from a 3-dimensional projective space we construct divisible designs admitting GL(3,q) as an automorphism group. 相似文献
90.
Since Markowitz (1952) formulated the portfolio selection problem, many researchers have developed models aggregating simultaneously several conflicting attributes such as: the return on investment, risk and liquidity. The portfolio manager generally seeks the best combination of stocks/assets that meets his/her investment objectives. The Goal Programming (GP) model is widely applied to finance and portfolio management. The aim of this paper is to present the different variants of the GP model that have been applied to the financial portfolio selection problem from the 1970s to nowadays. 相似文献