Blind source separation for ambulatory sleep recording.

This paper deals with the conception of a new system for sleep staging in ambulatory conditions. Sleep recording is performed by means of five electrodes: two temporal, two frontal and a reference. This configuration enables to avoid the chin area to enhance the quality of the muscular signal and the hair region for patient convenience. The electroencephalopgram (EEG), eletromyogram (EMG), and electrooculogram (EOG) signals are separated using the Independent Component Analysis approach. The system is compared to a standard sleep analysis system using polysomnographic recordings of 14 patients. The overall concordance of 67.2% is achieved between the two systems. Based on the validation results and the computational efficiency we recommend the clinical use of the proposed system in a commercial sleep analysis platform.     

Effect of extrusion-cooking on the hypoglycaemic properties of citrus fibre: An in-vitro study

Orange and lemon peels were extruded under controlled conditions of varying severity, and their physico-chemical characteristics and effect on the enzymatic hydrolysis of starch and glucose diffusion were studied. Extrusion-cooking treatment increased the soluble fraction of dietary fibre as well as solubilised pectic substances and arabino-galactomannan chains. The apparent viscosities of aqueous extracts of extruded fibre were increased slightly for orange and more markedly for lemon fibre. With both fibre sources, viscosities values were higher in Tris-maleate buffer (0.1 M) than in NaCl (154 mM). However, these modifications had no effect on starch hydrolysis and glucose diffusion in vitro.     

Specificity of Pheromonal and Kairomonal Response of the Israeli Pine Bast Scale Matsucoccus josephi and Its Predator Elatophilus hebraicus

It has been demonstrated previously that the sex pheromone of the Israeli pine bast scale, Matsucoccus josephi, (2E,5R,6E,8E)-5,7-dimethyl2,6,8-decatrien-4-one (1) is also a potent kairomone of the scale insect's predator Elatophilus hebraicus. Surprisingly, the sex pheromones of M. feytaudi (2) and M. matsumurae (3) also attract E. hebraicus. These results have prompted us to prepare a series of analogs of 1 with variations in the two moieties attached to the C=O group (4–9) in order to probe the structure–activity relationship of the pheromonal/kairomonal response of M. josephi and E. hebraicus. The most selective and active pheromone analog is 8, attracting only M. josephi males and the most selective and active kairomone analog is the M. feytaudi pheromone 2, attracting only adults of E. hebraicus. A dose–response field test of these analogs and the chiral and racemic M. josephi pheromone 1 indicates that the specificity is maintained at a broad range between 25 and 400 g corresponding to 1. Analog 5, which is neither a parapheromone nor a kairomone, and analog 8, which is only a parapheromone, are not inhibitory to M. josephi or to E. hebraicus. Our study indicates that alterations in the diene side chain of 1, common to all three Matsucoccus pheromones, strongly reduce the kairomonal activity while structural changes in the second side chain significantly reduce the pheromonal activity. The discovery of selective analogs of 1 has practical implications and enables specific monitoring of M. josephi or E. hebraicus. Particularly important is the possibility to mass-trap males of M. josephi without reducing the population of E. hebraicus.     

Structural characterization of oligomers from the polycondensation of citric acid with ethylene glycol and long‐chain aliphatic alcohols

The structural characterization of polyesters of citric acid (CA) with ethylene glycol and long‐chain aliphatic alcohols (ROH), prepared by the composition of the reaction mixture being adjusted slightly away from stoichiometric equivalence, was performed with ¹H‐ and ¹³C‐NMR spectroscopy. The aliphatic alcohols employed were 1‐decanol, 1‐dodecanol, and 1‐octadecanol. The ¹³C‐NMR carbonyl region presented four groups of signals, two corresponding to the ester groups and two corresponding to the acid groups. However, symmetric and asymmetric groups of CA moieties were identified in the ¹³C‐NMR spectra. The ester yield from ROH decreased as the number of carbon atoms in the alcohols increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 302–306, 2003     

A useful approach towards solid–liquid extraction of metal cations with unsupported calixarenes

This article describes a convenient and effective method to study the extraction properties of unsupported calixarenes used as solid extracting agents. The solid–liquid extraction properties of different functionalized calixarene derivatives were studied. This method was compared to classic liquid–liquid extractions. The reproducibility of the solid–liquid extractions was studied among with the calixarene recycling. Results obtained for Cu²⁺, Cd²⁺and Pb²⁺extractions using both methods have revealed the interest to use calixarenes as solid extracting agents. Moreover, a study of selective extraction has been carried out.     

Thermal reaction of SiC films with tungsten and tungsten–rhenium alloys

Solid-state reactions between SiC films and W–xRe (x = 0, 5 and 25 at%) substrates on thermal annealing between 1673 K and 1873 K for various durations have been investigated. SiC coatings were deposited on metallic wires by hot filament chemical vapour deposition (HFCVD) from a gas mixture of tetramethylsilane (TMS) and hydrogen at 1373 K under normal pressure. The interface zones were characterized using scanning electron and optical microscopies, X-ray diffraction and electron microprobe microanalysis. All analyses reveal that SiC reacts with substrates. Various metal silicides and carbides were formed in layered reaction and the presence of these phases was confirmed by electron probe microanalysis. The effects of rhenium on the reactivity were established by the determination of growth kinetics deducted from the thicknesses of reaction zones as a function of annealing time. It has been found that an increase in the diffusion kinetics and activation energy with the quantity of rhenium in the tungsten wire.     

Experimental study of the stacking sequence effect on polymer/composite multi-layers submitted to thermomechanical cyclic loadings

Fast filling of hydrogen pressure tank leads to thermomechanical stresses in vessel structure. In this paper, the aim is to study the thermomechanical behaviour of the material used in the vessel structure. Flat coupons made of the same constituents as the hydrogen tank materials and with different stacking sequences have been tested under quasi-static tensile tests and fatigue. Three types of fatigue tests have been performed in order to understand damage mechanisms due to interactions between thermal and mechanical stresses: thermomechanical fatigue, 1 Hz mechanical fatigue and mechanical fatigue with a constant stress level stage. Damage development has been followed by acoustic emission and microscopic observations. Results show that, whatever the applied loading, there is a significant influence of the stacking sequence of the composite part. Moreover, the comparison of the material response to the different types of fatigue has revealed the harmful role of coupled temperature/mechanical cyclic stresses.     

Optochemical Control of Bacterial Gene Expression: Novel Photocaged Compounds for Different Promoter Systems

Photocaged compounds are applied for implementing precise, optochemical control of gene expression in bacteria. To broaden the scope of UV-light-responsive inducer molecules, six photocaged carbohydrates were synthesized and photochemically characterized, with the absorption exhibiting a red-shift. Their differing linkage through ether, carbonate, and carbamate bonds revealed that carbonate and carbamate bonds are convenient. Subsequently, those compounds were successfully applied in vivo for controlling gene expression in E. coli via blue light illumination. Furthermore, benzoate-based expression systems were subjected to light control by establishing a novel photocaged salicylic acid derivative. Besides its synthesis and in vitro characterization, we demonstrate the challenging choice of a suitable promoter system for light-controlled gene expression in E. coli. We illustrate various bottlenecks during both photocaged inducer synthesis and in vivo application and possibilities to overcome them. These findings pave the way towards novel caged inducer-dependent systems for wavelength-selective gene expression.     

Performance-based indicators for controlling geosynthetic clay liners in landfill applications

The results of a project aimed at identifying performance-based indicators that can be used by landfill operators to check the suitability of GCLs for bottom barrier applications are presented. The general methodology consisted of performing detailed characterization of the prevalent GCLs used in France for landfill barrier applications, before and after prolonged contact with several fluids during oedo-permeameter tests. Results of mineralogical analysis illustrate the variety of composition of the tested bentonites, which in addition to smectite clay contain a large number of accessory minerals. For one of the GCLs tested, the proportion of smectite was lower than 30 wt%, which highlights the limitations of the generic designation “bentonite” when referring to GCLs destined to landfill applications. Results also underline the correlation between cation exchange capacity (CEC) and smectite content, the correlation between free swell volume and proportion of exchangeable sodium and the influence of the bentonite's calcium carbonate fraction on hydraulic conductivity. Transmission electron microscopy (TEM) photographs illustrate the effect of cation exchange on clay microstructure, with the formation of clay particles which lead to increased hydraulic conductivity. The exchange is also documented by exchangeable cation analyses. Results of isotopic analyses indicate that information provided by suppliers with respect to the “natural” versus “activated” nature of the bentonite, may sometimes be arbitrary and related to factors that are very difficult to check in practice, even by the suppliers themselves. This further underlines the need for performance-based indicators, rather than generic designations, to provide objective information regarding GCL suitability for landfill applications. Several performance-based indicators are selected in order to provide practical tools for checking the suitability of sodium-bentonite GCLs in bottom barrier applications and limit values are proposed.