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21.
Tumor-associated macrophages play a key role in promoting tumor progression by exerting an immunosuppressive phenotype associated with the expression of programmed cell death ligand 1 (PD-L1). It is well known that tumor-derived small extracellular vesicles (SEVs) affect the tumor microenvironment, influencing TAM behavior. The present study aimed to examine the effect of SEVs derived from colon cancer and multiple myeloma cells on macrophage functions. Non-polarized macrophages (M0) differentiated from THP-1 cells were co-cultured with SEVs derived from a colorectal cancer (CRC) cell line, SW480, and a multiple myeloma (MM) cell line, MM1.S. The expression of PD-L1, interleukin-6 (IL-6), and other inflammatory cytokines as well as of the underlying molecular mechanisms were evaluated. Our results indicate that SEVs can significantly upregulate the expressions of PD-L1 and IL-6 at both the mRNA and protein levels and can activate the STAT3 signaling pathway. Furthermore, we identified the TLR4/NF-kB pathway as a convergent mechanism for SEV-mediated PD-L1 expression. Overall, these preliminary data suggest that SEVs contribute to the formation of an immunosuppressive microenvironment.  相似文献   
22.
The paper describes and discusses the results of an extensive testing programme on the structural behaviour of timber connections under ISO‐fire. The results of reference tests performed at normal temperature are also presented. From the variety of timber connections multiple shear steel‐to‐timber connections with dowels and slotted‐in steel plates and connections with steel side plates and annular ringed shank nails were experimentally studied. Particular attention was given to the analysis of the efficiency of different strategies in order to increase the fire resistance of the timber connections. The test results showed that unprotected multiple shear steel‐to‐timber connections with dowels designed for normal temperature reached a fire resistance of about 30 min. A reduction of the load level applied during the fire did not lead to a significant increase of the fire resistance. By increasing the side timber members as well as the end distance of the dowels by 40 mm the connections reached a fire resistance of more than 70 min. Connections protected by timber boards or gypsum plasterboards showed a fire resistance of around 60 min. Thus, from a fire design point of view these strategies were favourable in order to increase the fire resistance of the connections significantly. Unprotected connections with steel side plates and annular ringed shank nails failed already after about 12 min due to large deformations of the nails and the steel side plates directly exposed to fire. By protecting the steel side plates using an intumescent paint the fire resistance of the connections was increased to around 30 min. The test results enlarged the experimental background of timber connections in fire significantly. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
23.
4-Chloro-N-(pyridin-2-ylmethyl)aniline (CPYA) was synthesized by a simple and inexpensive method and tested as a corrosion inhibitor in acid medium for mild steel by using gravimetric studies and electrochemical measurements. An average maximum efficiency of 96.0% was achieved at 4.59 mmol/L. Corrosion kinetic and thermodynamic parameters were also analyzed. Surface analyses (atomic force microscopy and scanning electron microscopy) show that protection is enabled by adsorption on the metal, forming a film. Quantum chemical calculations were performed to access information regarding the molecular structure in the corrosive medium and to support interpretation of the results obtained by experimental methods.  相似文献   
24.
The phylum Thermotogae is composed of a single class (Thermotogae), 4 orders (Thermotogales, Kosmotogales, Petrotogales, Mesoaciditogales), 5 families (Thermatogaceae, Fervidobacteriaceae, Kosmotogaceae, Petrotogaceae, Mesoaciditogaceae), and 13 genera. They have been isolated from extremely hot environments whose characteristics are reflected in the metabolic and phenotypic properties of the Thermotogae species. The metabolic versatility of Thermotogae members leads to a pool of high value-added products with application potentials in many industry fields. The low risk of contamination associated with their extreme culture conditions has made most species of the phylum attractive candidates in biotechnological processes. Almost all members of the phylum, especially those in the order Thermotogales, can produce bio-hydrogen from a variety of simple and complex sugars with yields close to the theoretical Thauer limit of 4 mol H2/mol consumed glucose. Acetate, lactate, and L-alanine are the major organic end products. Thermotagae fermentation processes are influenced by various factors, such as hydrogen partial pressure, agitation, gas sparging, culture/headspace ratio, inoculum, pH, temperature, nitrogen sources, sulfur sources, inorganic compounds, metal ions, etc. Optimization of these parameters will help to fully unleash the biotechnological potentials of Thermotogae and promote their applications in industry. This article gives an overview of how these operational parameters could impact Thermotogae fermentation in terms of sugar consumption, hydrogen yields, and organic acids production.  相似文献   
25.
A steady buoyancy-driven flow of air in a partially open square 2D cavity with internal heat source, adiabatic bottom and top walls, and vertical walls maintained at different constant temperatures is investigated numerically in this work. A heat source with 1% of the cavity volume is present in the center of the bottom wall. The cold right wall contains a partial opening occupying 25%, 50% or 75% of the wall. The influence of the temperature gradient between the verticals walls was analyzed for Rae = 103–105, while the influence of the heat source was evaluated through the relation R = Rai/Rae, investigated at between 400 and 2000. Interesting results were obtained. For a low Rayleigh number, it is found that the isotherm plots are smooth and follow a parabolic shape indicating the dominance of the heat source. But as the Rae increases, the flow slowly becomes dominated by the temperature difference between the walls. It is also observed that multiple strong secondary circulations are formed for fluids with a small Rae whereas these features are absent at higher Rae. The comprehensive analysis is concluded with horizontal air velocity and temperature plots for the opening. The numerical results show a significant influence of the opening on the heat transfer in the cavity.  相似文献   
26.
This article presents an investigation into natural convection in trapezoidal cavities. It examines a cavity whose floor and upper inclined walls are both adiabatic, while the vertical walls are isothermal. For these isothermal walls, we consider two thermal boundary conditions. Under the first condition, the short wall on the left side is heated as the tall one on the right side is cooled. The second condition is the reverse of the first—the short wall is cooled as the tall one is heated. Considering laminar conditions and a two-dimensional system, steady-state computations are carried out to assess the effects of one and two baffles, the baffle's height (H b ), Rayleigh number, 103 ≤ Ra ≤ 106, and three Prandtl number values. To demonstrate the various effects, the results from several designed case studies are shown in terms of isotherms, streamlines, and local and average Nusselt numbers in order. Predictions reveal that the second baffle decreases the cavity's fluid flow and heat transfer. As the height of the baffle rises, the heat transfer drops drastically. Also, two baffles produce more pronounced thermal stratification than only one.  相似文献   
27.
Algorithms for the coalitional manipulation problem   总被引:1,自引:0,他引:1  
We investigate the problem of coalitional manipulation in elections, which is known to be hard in a variety of voting rules. We put forward efficient algorithms for the problem in Borda, Maximin and Plurality with Runoff, and analyze their windows of error. Specifically, given an instance on which an algorithm fails, we bound the additional power the manipulators need in order to succeed. We finally discuss the implications of our results with respect to the popular approach of employing computational hardness to preclude manipulation.  相似文献   
28.
A trustable and accurate ground truth is a key requirement for benchmarking self-localization and mapping algorithms; on the other hand, collection of ground truth is a complex and daunting task, and its validation is a challenging issue. In this paper we propose two techniques for indoor ground truth collection, developed in the framework of the European project Rawseeds, which are mutually independent and also independent on the sensors onboard the robot. These techniques are based, respectively, on a network of fixed cameras, and on a network of fixed laser scanners. We show how these systems are implemented and deployed, and, most importantly, we evaluate their performance; moreover, we investigate the possible fusion of their outputs.  相似文献   
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