Scaling of fire extinguishment data

The results of small-scale tests of fire extinguishment by total flooding with Halon 1301, when compared on a normalized basis, with those of large-scale tests conducted by other organizations indicated that the small-scale test results predict accurately the amounts of hydrogen fluoride formed during the extinguishment of full-size fires.     

Progress in the Development of Platelet‐Activating Factor Receptor (PAFr) Antagonists and Applications in the Treatment of Inflammatory Diseases

Platelet‐activating factor (PAF) and its receptor (PAFr) have been implicated in a wide range of diseases and disorders that originate from the activation of inflammatory pathways. Although the exact structure of the binding site on the PAFr remains unknown, the PAFr is a well‐established therapeutic target, and an array of structurally diverse PAFr antagonists have been identified. These include compounds that are structurally similar to the natural PAF ligand, synthetic heterocycles, complex polycyclic natural products, and various metal complexes. This review provides an update on more than 20 years of progress in this area. The development and synthesis of new PAFr antagonists, structure–activity relationship studies, the biological activity of these molecules, and their therapeutic potential are discussed.     

The effect of remodelling and contractility of the actin cytoskeleton on the shear resistance of single cells: a computational and experimental investigation

The biomechanisms that govern the response of chondrocytes to mechanical stimuli are poorly understood. In this study, a series of in vitro tests are performed, in which single chondrocytes are subjected to shear deformation by a horizontally moving probe. Dramatically different probe force–indentation curves are obtained for untreated cells and for cells in which the actin cytoskeleton has been disrupted. Untreated cells exhibit a rapid increase in force upon probe contact followed by yielding behaviour. Cells in which the contractile actin cytoskeleton was removed exhibit a linear force–indentation response. In order to investigate the mechanisms underlying this behaviour, a three-dimensional active modelling framework incorporating stress fibre (SF) remodelling and contractility is used to simulate the in vitro tests. Simulations reveal that the characteristic force–indentation curve observed for untreated chondrocytes occurs as a result of two factors: (i) yielding of SFs due to stretching of the cytoplasm near the probe and (ii) dissociation of SFs due to reduced cytoplasm tension at the front of the cell. In contrast, a passive hyperelastic model predicts a linear force–indentation curve similar to that observed for cells in which the actin cytoskeleton has been disrupted. This combined modelling–experimental study offers a novel insight into the role of the active contractility and remodelling of the actin cytoskeleton in the response of chondrocytes to mechanical loading.     

Effect of sonication on the bioactive,quality and rheological characteristics of fruit smoothies

Power ultrasound was investigated as a nonthermal processing technique for fruit smoothies. Smoothies were sonicated at different amplitude levels (24.4–61.0 μm) for processing times (3–10 min). Total antioxidant capacity (TAC), total phenolics (TP), colour parameters, particle size and rheological characteristics were assessed. Sensory evaluation was conducted on selected samples for acceptability. Highest reductions in TAC (P < 0.001) and TP (P < 0.001) were observed at the maximum amplitude level (61.0 μm). Sonication reduced colour and rheological parameters and shortened particle size compared with fresh and thermal smoothies. However, sonicated samples received satisfactory (>3) sensory acceptability scores. Response surface methodology was applied to determine the effect of amplitude level and processing time on TP, TAC and colour parameters. A second‐order polynomial model fitted well to TP (R² = 0.74) and TAC (0.79) experimental data. Lower values were obtained for colour parameters, possibly because of processing limitations. Alternatives to overcome these limitations are discussed.     

An Informed Environment Dedicated to the Simulation of Virtual Humans in Urban Context

In this paper, we outline the creation of an Informed Environment, dedicated to urban life simulation.We propose methods and tools for creating and providing the information necessary for animating virtual humans in a city using an Informed Environment. The Informed Environment is based on a hierarchical decomposition of a urban scene into Environment Entities providing geometrical information as well as semantic notions, thus allowing a more realistic simulation of human behaviour. In this manner, virtual humans can integrate with a certain kind of urban knowledge.     

A decision-oriented model to evaluate the effect of land use and agricultural management on herbicide contamination in stream water

Modelling stream water pollution by herbicides in agricultural areas is a critical issue since numerous and incompletely known processes are involved. A decision-oriented model, SACADEAU-Transf, which represents water and pesticide transfer in medium-sized catchments (10–50 km²) is presented. This model aims at evaluating the effect of land use, agricultural practice and landscape on the contamination of stream water in rural catchments. The processes are represented in an easily understandable way with a moderate amount of information, producing semi-quantitative and spatialized outputs. Modelling focuses on the first few months after herbicide application when high levels of contamination are generally observed, by considering transfer through the catchment area via surface and subsurface flow. The surface flow, based on a tree plot network representation of the catchment, is controlled by soil-surface properties and saturated conditions. The subsurface flow based on Topmodel concepts is controlled by the topography. Herbicide transfer is coupled to water transfer by taking into account the main characteristics of the chemicals. The model simulates the daily water and herbicide outflow at the outlets of the farmers' fields as well as from the catchment. Preliminary results on maize herbicide transfer are presented for an agricultural catchment with an area of 17 km² located in north-western France. The relevance of SACADEAU-Transf model is discussed in view of the qualities required for the decision-oriented models developed for improving agro-environmental management.     

Microwave synthesis and properties of NaPO3–SnO–Nb2O5 glasses

Tin niobiophosphate glasses were produced using a domestic microwave oven under a nitrogen flow. The fast microwave melting method and the protective atmosphere prevent the oxidation of SnO. After 10 min of heating, the NaPO₃, SnO, and Nb₂O₅ mixtures are homogeneous and permit to obtain transparent glasses. Three series of glasses with different Sn/Nb ratio were studied to determine the influence of each oxide. The glass transition temperature increases linearly with the amount of Nb₂O₅ and SnO. These variations are more important for compositions with high metallic cation proportions and with a low Sn/Nb ratio. The same evolutions were observed for the density, Vickers hardness, and elastic modulus while the thermal expansion coefficient decreases monotonously. The simultaneous insertion of SnO and Nb₂O₅ in phosphate glass matrix leads to a progressive strengthening of the glass network. The chemical durability of the glasses also increases as a function of the amount of metal oxides. We prepared a bulk glass sample with a dissolution rate of about 3.3 × 10⁻⁸ g cm⁻² min⁻¹ in renewed water conditions at 95 °C. This durability is equivalent to those of the window glass whereas the glass transition temperature remains lower than 485 °C.