X-ray microanalysis of native airway surface liquid collected by cryotechnique

The airway surface liquid (ASL) that lines the surface epithelium of the tracheobronchial tree is of vital importance to the airway defence against microbial invasion and damage due to environmental factors. Little is known about the ASL collected in situ in native conditions, owing to difficulties in collecting ASL without causing damage to the airway mucosa. We have developed a method to collect and analyse the elemental composition of tracheal ASL in pathogen-free mice. A specially designed cryoprobe, adapted to the internal curvature of the mouse trachea, was used to collect the native ASL from the tracheal surface. The complete ASL elemental composition including [Na] = 5.5 ± 0.3, [Cl] = 1.3 ± 0.3, [K] = 1.1 ± 0.2, [Ca] = 1.2 ± 0.3, [P] = 1.5 ± 0.8, [S] = 1.7 ± 0.4 and [Mg] = 1.3 ± 0.4 mmol L¹ was determined by X-ray microanalysis. We demonstrate here that the technique that we used for ASL collection maintained perfectly the airway epithelial integrity and functionality.     

Computerized histomorphometric study of the splenic collagen polymorphism: A control‐tissue for polarization microscopy

Previous articles have pointed out the presence of type III collagen within the extracellular structure of the parenchymatous organs. This study aimed to quantitatively characterize the collagen polymorphism at the capsule and parenchymal trabeculae of the largest lymphoid organ of the body i.e., the spleen, in mouse, rat, and rabbit models. Following a Picrosirius Red‐Polarization procedure and computer assisted image analysis of paraffin sections, the results showed (1) a predominant and significantly higher amount of type III collagen in the trabeculae area compared to the capsule area in the three species, (2) no statistical difference among the three species concerning the parenchymal collagen polymorphism or the type I/type III collagen ratio, (3) a heterogeneous type I/type III collagen ratio varying from 0.86 (mouse) to 6.62 (rabbit) in the fibromuscular capsule region. A qualitative analysis corroborated these histomorphometric results. In conclusion, the spleen may be used as (1) a control tissue to qualitatively visualize type I and III collagen under polarization microscopy and to validate the quality of PSR staining (2) an aid to accurately calibrate the angle of polarization before quantitative measurements of type I and type III collagen. Among the studied species, the rabbit spleen appeared to be the most appropriate control tissue as it showed the highest amount of type I collagen in the capsule and a similarly high amount of type III collagen in the parenchymal trabeculae. Microsc. Res. Tech. 78:900–907, 2015. © 2015 Wiley Periodicals, Inc.     

Constraint graph-based approach for the analysis and the control of time critical systems

The increasing complexity of manufacturing systems gives rise to the development of new formal methods allowing to handle their particularities. Petri nets are a powerful formalism for the specification and verification of concurrent systems including sequential systems and manufacturing systems. To deal with systems whose time issues become fundamental, different time Petri nets extensions have been developed in the literature, each one being dependent on the application considered. For the time critical systems, their correctness depends not only on the logic correctness but also on the time constraints. Timing issues are essential. In this paper, a new method of analysis and control for P-time Petri nets is proposed. It is based on the firing instant notion and exploits a constraint graph approach.     

NSR Catalysis studied using Scanning Tunnelling Microscopy

In this paper we report the fabrication of model catalysts prepared to understand the structure of the BaO surface. This utilises the ‘inverse’ catalyst method, that is, the oxide layer is fabricated onto the top of a metal single crystal surface. We show that we can atomically resolve the surface structure of BaO(111) and that it presents a (2×2) reconstruction at its surface. Under other dosing conditions we can produce a layer which is metastable at 573K, which we believe to be the peroxide, BaO₂. We have shown that the BaO layer can store NO_x from a mix of NO and oxygen, even under the extremely low exposure conditions of UHV, proving that the NOx storage process is a facile one. The results indicate that it is not necessary to have NO2 in the gas phase in order to store NO_x.     

Suitable cooling program for chicken fat dry fractionation

The impacts of the cooling program on crystal morphology, crystal suspension filtration properties and the characteristics of fractions resulting from chicken fat dry fractionation were assessed. The quality of the fractions was found to depend on the nature of the crystallized material and was also closely related to the filtration properties of the crystal suspension, which in turn were controlled by the cooling conditions. A slow cooling rate during the nucleation step was necessary to enhance process selectivity, and this rate could be accelerated once the first crystals had formed. These findings enhanced our understanding of the mechanisms involved during dry fractionation and highlighted the efficacy of a three‐phase cooling program, including (1) cooling from 70 to 26 °C, (2) slowdown in the cooling rate, and (3) a second rapid cooling down to the final temperature at which the fat is held for a specified time.     

In silico classification of HERG channel blockers: a knowledge-based strategy

The blockage of the hERG potassium channel by a wide number of diverse compounds has become a major pharmacological safety concern as it can lead to sudden cardiac death. In silico models can be potent tools to screen out potential hERG blockers as early as possible during the drug-discovery process. In this study, predictive models developed using the recursive partitioning method and created using diverse datasets from 203 molecules tested on the hERG channel are described. The first model was built with hERG compounds grouped into two classes, with a separation limit set at an IC50 value of 1 microm, and reaches an overall accuracy of 81%. The misclassification of molecules having a range of activity between 1 and 10 microM led to the generation of a tri-class model able to correctly classify high, moderate, and weak hERG blockers with an overall accuracy of 90%. Another model, constructed with the high and weak hERG-blocker categories, successfully increases the accuracy to 96%. The results reported herein indicate that a combination of precise, knowledge management resources and powerful modeling tools are invaluable to assessing potential cardiotoxic side effects related to hERG blockage.     

Microstructure and properties of pitch-based carbon composites

Pitches prepared in the laboratory by thermal treatment and air-blowing of a commercial coal-tar pitch were used as matrix precursors of carbon composites using granular petroleum coke, foundry coke, amorphous graphite and anthracite. Pitches were characterized by standard procedures (elemental analysis, softening point, solubility tests and carbon yield) and light microscopy (mesophase content). Pitch pyrolysis behaviour was monitored by thermogravimetric analysis and from the optical texture of cokes. Pitch wettability to the different carbons, at different temperatures, was also studied. Experimental conditions selected for the preparation of composites were based on pitch composition and properties. The main microstructural features of composites were determined by light microscopy and scanning electron microscopy. Composite properties were described in terms of their density, porosity and compressive strength, and related to composite microstructure and the characteristics of the precursors. Thermal treatment and air-blowing of pitch improved carbon composite structure and properties. The lowest porosities and best mechanical properties were observed in those composites obtained with the thermally treated pitches combined with foundry coke and anthracite.     

Quantitative immunolocalization of a P29 protein (GRA7), a new antigen of toxoplasma gondii

The rapid reactions of nitrosoarenes with cellular SH groups have proved to be main metabolic conversions during detoxication. Interactions of the phenacetin metabolite 4-nitrosophenetole with glutathione have been investigated in detail during the last years, revealing a complex pattern of products depending on the stoichiometry of the reactants and reaction conditions. Eight metabolites have been identified hitherto, and the present work extends this medley by six additional products. Three metastable sulfenamides, 4-ethoxy-2,N-bis(glutathion-S-yl)-aniline, N4-(glutathion-S-yl)-4-amino-4'-ethoxydiphenylamine, and N-(glutathion-S-yl)-4-aminophenol, as well as the N-sulfenylquinonimine N-(glutathion-S-yl)-1,4-benzoquinonimine were characterized by chemical reactivity, chromatographic behavior, UV/vis absorption, 1H NMR, and FAB-MS data. The structure of the sulfenamide 2,N4-bis(glutathion-S-yl)-4-amino-4'-ethoxydiphenylamine could not be proved unequivocally, but is strongly suggested due to the chemical reactivity, chromatographic behavior, and UV/vis absorption of the compound. Finally, traces of 4-aminophenol were detected. A reaction scheme is presented explaining the formation of all identified metabolites via a central sulfenamide cation. Molecular orbital calculations for this sulfenamide cation have been performed, corroborating the proposed reaction mechanisms on the basis of Klopman's generalized perturbation theory.     

All-optical regeneration techniques

Basic principles of all-optical signal regeneration are presented, and main state-of-art techniques are reviewed. Optical fiber and semiconductor based devices are addressed, and some recently reported 2R and 3R signal regeneration experiments are discussed.     

Preparation of nano‐sized silica/poly(methyl methacrylate) composite latexes by heterocoagulation: comparison of three synthetic routes

Continuing earlier work, 2,2′‐azobis(isobutyramidine) dihydrochloride (AIBA) was used as a cationic initiator to generate positively charged polymers, and promote interaction of these polymers with the negatively charged surface of colloidal silica particles in aqueous solution. Three different synthetic routes have been investigated. In a first route, emulsion polymerization of MMA, initiated by AIBA, was performed directly in an aqueous suspension of the silica beads using a non‐ionic polyoxyethylenic surfactant (NP₃₀). In a second route, AIBA was first adsorbed on the silica surface, and the free amount of initiator was discarded from the suspension. The silica‐adsorbed AIBA adduct was suspended in water with the help of surfactant, and used to initiate the emulsion polymerization of MMA. In a third route, cationic PMMA particles were synthesized separately and subsequently adsorbed on the silica surface. Whatever the approach used for their elaboration, the colloidal nanocomposites were shown to exhibit a raspberry‐like morphology. Quantitative determination of the amount of surface polymer enabled us to evaluate the efficiency of the heterocoagulation process and establish a comparison among the three synthetic routes. Copyright © 2004 Society of Chemical Industry