Analysis of protein domain families in Caenorhabditis elegans

The Caenorhabditis elegans genome sequencing project has completed over half of this nematode's 100-Mb genome. Proteins predicted in the finished sequence have been compiled and released in the data-base Wormpep. Presented here is a comprehensive analysis of protein domain families in Wormpep 11, which comprises 7299 proteins. The relative abundance of common protein domain families was counted by comparing all Wormpep proteins to the Pfam collection of protein families, which is based on recognition by hidden Markov models. This analysis also identified a number of previously unannotated domains. To investigate new apparently nematode-specific protein families, Wormpep was clustered into domain families on the basis of sequence similarity using the Domainer program. The largest clusters that lacked clear homology to proteins outside Nematoda were analyzed in further detail, after which some could be assigned a putative function. We compared all proteins in Wormpep 11 to proteins in the human, Saccharomyces cerevisiae, and Haemophilus influenzae genomes. Among the results are the estimation that over two-thirds of the currently known human proteins are likely to have a homologue in the whole C. elegans genome and that a significant number of proteins are well conserved between C. elegans and H. influenzae, that are not found in S. cerevisiae.     

Thin steel plate shear walls behavior and analysis

Steel plate shear walls have been used in buildings in North America and Japan. Until recently, the design practice has been to limit the strength of the wall to the buckling strength of the plate. The post-buckling strength of thin plates subjected to shear has been recognized for more than 60 years, since it was outlined by Wagner in the early 1930s. Tests of a quarter and one third scale specimens of thin steel plate shear walls under cyclic loading were performed; the tests are described and the results are summarized. An analytical model to determine the behavior of thin steel plate shear walls was developed and is given. The model is capable of depicting the behavior of walls with plates welded or bolted to the surrounding beams and columns of the building frame. Comparisons between the analytical and experimental results are made.     

A simplified sequence for observing deoxymyoglobin signals in vivo: myoglobin excitation with dynamic unexcitation and saturation of water and fat (MEDUSA)

This paper describes a new, simplified pulse sequence for observing NMR signals from deoxymyoglobin in vivo. Paramagnetically shifted resonances from deoxymyoglobin can be exploited to noninvasively calculate intracellular oxygen tension in striated muscle. However, special sequences are required to observe these weak signals against the larger water and fat signals encountered in vivo. The pulse sequence described here, which is based on inversion recovery sequences, efficiently suppresses both water and fat resonances and can be implemented with short repetition rates. Moreover, it is perfectly suited for studies with surface coils, where RF inhomogeneities render other popular suppression sequences ineffective.     

Tricyclic antidepressant-induced lipidosis in human peripheral monocytes in vitro, as well as in a monocyte-derived cell line, as monitored by spectrofluorimetry and flow cytometry after staining with Nile red

Human mono- and lymphocytes from peripheral blood and the monoblastoid cell line U-937 were used in this in vitro study of drug-induced lipidosis. Mono- and lymphocytes were exposed for 4 days to three different tricyclic antidepressants (TCAs), imipramine (25 microM), clomipramine (10 microM) and citalopram (80 microM). The lipophilic fluorophore Nile red, which stains intracellular lipid structures selectively, was used as a lipid probe. Fluorescence microscopy, spectrofluorimetry and flow cytometry were used to detect cellular lipidosis, as verified by electron microscopy. Our results demonstrate that imipramine, clomipramine and citalopram induce lipidosis in monocytes and U-937 cells, but not in lymphocytes. An accurate quantitation of induced intracellular lipidosis can be achieved by spectrofluorimetric and flow cytometric analysis.     

Non-isothermal crystallization kinetics of Ag-As2S3 semiconductor glasses

Using a differential thermal analysis technique to give single scan thermograms, the transformation mode,n, and the activation energy of crystallization,E, were determined for the chalcogenide glasses of the system Ag _x (As₂S₃)_100–x' withx=6, 15 and 25. Bothn andE were found to be compositionally dependent. The value ofn varies between 2.1 and 3.6, and that ofE between 2.4 and 3.6 eV. The crystallization kinetic data were explained using X-ray diffraction results of amorphous and crystalline structures.     

Influence of composite materials confinement on alkali aggregate expansion

The Alkali-Aggregate Reaction (AAR) is a group of physicochemical reactions which occurs in the concrete between the interstitial solution (highly alkaline) and some mineral phases in the aggregates. The damage induced by the AAR to the concrete could be very important. Many old structures are attacked or will be attacked by AAR. Remedial measures to repair or limit the problem exist but they are often only partially effective and very expensive. The aim of our research is to carry out an experimental procedure in order to evaluate the influence of advanced composite materials confinement on the expansion and the mechanical behaviour of the alkali-aggregate reactive concrete.

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Résumé L'alcali réaction est un ensemble de réactions physico-chimiques dans le béton qui peuvent se produire entre la solution interstitielle (fortement alcaline) et certaines phases minérales présentes dans les granulats. Les dommages causés au béton par l'alcali réaction peuvent être très importants. Beaucoup de structures sont attaquées ou le seront par l'alcali réaction. Les remèdes pour réparer ou diminuer l'alcali réaction existent mais ils sont souvent peu efficaces et très chers. Le but de notre travail de recherche est d'évaluer expérimentalement l'influence des matériaux composites sur l'expansion et le comportement mécanique du béton alcali-réactif.

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Editorial note Prof. Patrice Hamelin is a RILEM Senior Member. He participates in the work of RILEM TC TRC ‘Textile reinforced concrete’.     

Dry machinability of nickel-based weld-hardfacing layers for hot tooling

This paper deals with a study on the dry machinability of the nickel-based hardfacing layers used in the manufacturing of hot tooling. Several machining tests were carried out on 56NiCrMoV7 steel block with thickness of 60 mm (substrate). Five layers of Hastelloy C type with thickness varying between 2 and 3 mm were deposited on the substrate using flux cored-wire welding (pulsed semi-automatic MIG). In the accelerated machining tests (AMT), only the nature of the hardfacing layers were changed. The cutting speed V_c of 80 m/min, the axial depth of cut a_p of 0.12 mm, the radial depth of cut a_c of 12 mm and the feed rate f_z of 0.05 mm/tooth were considered in the AMT tests. It was found that the main limitation of this hardfacing in machining is associated with its highly heterogeneous metallurgical structure. This heterogeneity consists of a dendritic network (ductile nickel phase) separated by a fragile interdendritic dispersion (carbide phase and fine or coarse precipitate phases). This is expressed during cutting tests by the high hardness of the workpiece surface that involves premature wear of cutting tools. This deterioration is caused by the adhesion of the produced chips (dry sticking friction) leading to notches and very severe chipping of the cutting edge, following a crumbling of the tool material.     

IR spectroscopic study on the thermal degradation of plastic security cover sheets of some documents

The change in IR spectra of plastic security cover sheets of ethylene vinylacetate copolymer during thermal treatment was investigated. The results obtained revealed that the temperature reduced the concentration of the ester group; moreover, the carbonyl band disappeared at high temperatures from 200 to 220°C, as well as broading of the absorption aliphatic–CH band. The change in the mechanical properties, degree of swelling in water, and refractive index of the samples during thermal treatment were also investigated. © 1993 John Wiley & Sons, Inc.