The regulation requirements for upholstered furniture are nationally defined and lead to very different safety levels across Europe. This paper studies the fire performance of upholstered furniture across Europe and demonstrates the differences in the fire safety of sofas in different countries. Real sofas were purchased over Europe and tested first alone then for several of them in a room scenario. The fire performance of such upholstered furniture is related to their constitution and possibly to the improvement of their performance by physical and/or chemical means. Results are presented from a performance point of view and not focusing on the different technical solutions that can be envisaged, such as fire barriers or flame retardants. The results clearly show the effect of stricter regulations, not necessarily on the maximum heat release but mainly on the time available to escape, which is critical in many fire scenarios. Such regulations may have a positive effect, but they have to be performance-based, evaluated properly, and implemented considering market surveillance. 相似文献
Blood rheology is a key determinant of tissue perfusion at rest and during exercise. The present study investigated the effects of race distance on hematological, blood rheological, and red blood cell (RBC) senescence parameters. Eleven runners participated in the Martigny–Combes à Chamonix 40 km race (MCC, elevation gain: 2300 m) and 12 others in the Ultra-Trail du Mont Blanc (UTMB, 171 km, elevation gain: 10,000 m). Blood samples were collected before and after the races. After the UTMB, the percentage of RBC phosphatidylserine (PS) exposure was not affected while RBC CD235a levels decreased and RBC-derived microparticles increased. In contrast, after the MCC, RBC PS exposure increased, while RBC CD235a and RBC-derived microparticles levels were not affected. The free hemoglobin and hemolysis rate did not change during the races. RBC aggregation and blood viscosity at moderate shear rates increased after the MCC. RBC deformability, blood viscosity at a high shear rate, and hematocrit decreased after the UTMB but not after the MCC. Our results indicate that blood rheology behavior is different between a 40 km and a 171 km mountain race. The low blood viscosity after the ultra-marathon might facilitate blood flow to the muscles and optimize aerobic performance. 相似文献
Multilayered polymer films are increasingly used in the daily life, but their macroscopic properties are always limited by the layer–layer interfacial compatibility. In this work, the influence of interface modification through in situ layer–layer interfacial reaction during a multilayered assembly is revealed from micro‐ to nanolayer films, based on maleated poly(vinylidene fluoride) and polyamide‐6. In the presence of interfacial reaction and confinement, layer architecture and microstructure are highly dependent on the number of layers. Specifically, for nanolayer films having smaller layer thicknesses and higher reaction extent, layer integrity is reduced with the occurrence of interfacial instabilities. Depending on the microstructural evolution from multilayer assembly, those films exhibit quantitatively different extensional rheological and dielectric properties from micro‐ to nanolayers. More importantly, dielectric spectroscopy reveals the contribution of copolymer‐rich interphases to the dielectric performance of micro/nanolayered films. Additionally, charge transport dynamics in nanolayered films also differ significantly from their microlayered counterparts. They are attributed to the strong dependence of interfacial reaction extent and resulting microstructure on the number of layers and layer thicknesses. This work clearly illustrates how the control of layer–layer interfacial reaction in micro/nanolayer assembly can tune the interfacial, microstructure, and macroscopic properties of multilayered products. 相似文献
Extracellular vesicles (EVs) are membranous particles released by all cell types. Their role as functional carrier of bioactive molecules is boosted by cells that actively secrete them in biological fluids or in the intercellular space (interstitial EVs, iEVs). Here we have optimised a method for the isolation and characterization of zebrafish iEVs from whole melanoma tissues. Zebrafish melanoma iEVs are around 140 nm in diameter, as determined by nanoparticle tracking and transmission electron microscopy (TEM) analysis. Western blot analysis shows enrichment for CD63 and Alix in the iEV fraction, but not in melanoma cell lysates. Super resolution and confocal microscopy reveal that purified zebrafish iEVs are green fluorescent protein positive (GFP+), indicating that they integrate the oncogene GFP-HRASV12G used to induce melanoma in this model within their vesicular membrane or luminal content. Analysis of RNA-Seq data found 118 non-coding (nc)RNAs differentially distributed between zebrafish melanoma and their iEVs, with only 17 of them being selectively enriched in iEVs. Among these, the RNA components of RNAses P and MRP, which process ribosomal RNA precursors, mitochondrial RNAs, and some mRNAs, were enriched in zebrafish and human melanoma EVs, but not in iEVs extracted from brain tumours. We found that melanoma iEVs induce an inflammatory response when injected in larvae, with increased expression of interferon responsive genes, and this effect is reproduced by MRP- or P-RNAs injected into circulation. This suggests that zebrafish melanoma iEVs are a source of MRP- and P-RNAs that can trigger inflammation in cells of the innate immune system. 相似文献
Most of malware detectors are based on syntactic signatures that identify known malicious programs. Up to now this architecture
has been sufficiently efficient to overcome most of malware attacks. Nevertheless, the complexity of malicious codes still
increase. As a result the time required to reverse engineer malicious programs and to forge new signatures is increasingly
longer. This study proposes an efficient construction of a morphological malware detector, that is a detector which associates
syntactic and semantic analysis. It aims at facilitating the task of malware analysts providing some abstraction on the signature
representation which is based on control flow graphs. We build an efficient signature matching engine over tree automata techniques.
Moreover we describe a generic graph rewriting engine in order to deal with classic mutations techniques. Finally, we provide
a preliminary evaluation of the strategy detection carrying out experiments on a malware collection. 相似文献
In this work, we use an hybrid atomistic–continuum (HAC) simulation method to study transient and steady isothermal flows
of Lennard-Jones fluids near interfaces. Our hybrid method is based on a domain decomposition algorithm. The flow domain is
composed of two overlapping regions: an atomistic region described by molecular dynamics, and a continuum region described
by a finite volume discretization of the incompressible Navier–Stokes equations. To show the interest of such an hybrid method
to compute flows near fluid/solid interface, we first applied our hybrid scheme to the classical Couette flow, where the moving
wall is modelled at the atomistic scale. In addition, we also studied an oscillatory shear flow. Then, to compute flows near
fluid/fluid interface, we applied our method to a two-phase Couette flow (liquid/gas), where the interface is modelled at
the molecular scale. We show that hybrid results can sometimes differ from those provided by analytical solutions deduced
from continuum mechanics equations combined with usual boundary/interface relations. For the Couette and oscillatory shear
flows, a good agreement is found between hybrid simulations and macroscopic analytical solutions, however, we noticed that
the fluid in contact with the wall can be more entailed than what expected. For the liquid/gas Couette flow, the hybrid simulation
exhibits an unexpected jump of the velocity in the interfacial region, corresponding to a partial slip between the two fluid
phases. Those interesting results highlight the interest of using an HAC method to deal with systems for which surfaces/interfaces
effects are important. 相似文献
Indoor settled dust may result in substantial human exposure to chemicals, especially by ingestion following hand-to-mouth or hand-to-object-to-mouth contact. As with other environmental media related to exposure, dust may thus be subject to regulation. An international scientific workshop was convened in Paris in September 2019 firstly to assess the relevance for public health of setting guidelines for indoor settled dust, and secondly to discuss scientific and technical challenges related to such guidelines. The main discussions and conclusions, with consensus achieved, are reported herein. Discussions concerned general considerations, objectives and definitions, relevance for a health-based guideline, units of measure, and finally derivation of the guideline. These points should be addressed when considering an indoor settled dust guideline as part of a policy to reduce exposure indoors to a given chemical or group of chemicals. 相似文献
In the design of medium and low voltage equipment such as cable accessories, generator, motor end windings or bushings, issues with electrical field enhancement occur at interfaces between insulators and conductors, resulting in accelerated material ageing. The purpose of this paper is to present a novel dielectric composite material which has the properties to mitigate this local amplification. It is a functional dielectric which resistivity decreases by several orders with electric field from 1014 to 109 Ωm up to 1 kV?mm?1 while the dielectric constant decreases from 15 to 12 in the 10–2–106 Hz range. This novel material is made with graphite nanoplatelets. It may be used as a resistive or capacitive field grading material in electrical applications.
New 5-substituted vitamin E derivatives were semisynthesized, and their antibacterial activity against human Gram-positive and Gram-negative pathogens was evaluated. Several vitamin E analogues were active against methicillin-resistant Staphylococcus aureus (MRSA) and/or methicillin-resistant Staphylococcus epidermidis (MRSE); structure-activity relationships (SARs) are discussed. As a result, it is shown that the presence of a carboxylic acid function at the C-5 position and/or at the end of the side chain is crucial for the antibacterial activity. The bactericidal or bacteriostatic action of three compounds against MRSA and MRSE was confirmed in a time-kill kinetics study, and the cytotoxicity on human cells was evaluated. The preliminary mechanism study by confocal microscopy indicated that those vitamin E analogues led to bacterial cell death through membrane disruption. 相似文献