Circulating Monocyte Subsets and Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR), as an alternative to open heart surgery, has revolutionized the treatment of severe aortic valve stenosis (AVS), the most common valvular disorder in the elderly. AVS is now considered a form of atherosclerosis and, like the latter, partly of inflammatory origin. Patients with high-grade AVS have a highly disturbed blood flow associated with high levels of shear stress. The immediate reopening of the valve during TAVR leads to a sudden restoration of a normal blood flow hemodynamic. Despite its good prognosis for patients, TAVR remains associated with bleeding or thrombotic postprocedural complications, involving mechanisms that are still poorly understood. Many studies report the close link between blood coagulation and inflammation, termed thromboinflammation, including monocytes as a major actor. The TAVR procedure represents a unique opportunity to study the influence of shear stress on human monocytes, key mediators of inflammation and hemostasis processes. The purpose of this study was to conduct a review of the literature to provide a comprehensive overview of the impact of TAVR on monocyte phenotype and subset repartition and the association of these parameters with the clinical outcomes of patients with severe AVS who underwent TAVR.     

Correlation between configuration/conformation of zirconocenes on the stereoselectivity of the propylene polymerization reaction

Summary The catalytic performance (activity and polymer properties) of metallocenes with different symmetries in combination with methylaluminoxane (MAO) in the polymerization of propylene has been investigated at different temperatures, under standardized reaction conditions. The zirconocene rac-ethylene (⁵-1-indenyl) zirconium (IV) dichloride, with C₂ symmetry, produces isotatic polypropylene and isopropylidene(⁵-cyclopentadienyl (⁵-9-fluorenyl) zirconium (IV) dichloride, with C _S symmetry, syndiotactic polypropylene. The degree of the tacticity of these polymers increases with decreasing polymerization temperature. Only atactic polypropylene was formed with the unbridged zirconocenes bis(⁵-cyclopentadienyl) zirconium (IV) dichloride and bis(⁵-indenyl zirconium (IV) dichloride at any temperature investigated (10–60°C).     

Remote control of a robot in a map network

The automated control of manufacturing devices on a common communications network is a necessity for the factory of the future. The manufacturing automation protocol (MAP) represents a major effort by a group of companies towards meeting this need, and apparently is becoming a standard for factory-floor communications. In this project, an ASEA 2000 robot was used with a computer-controlled ply-cutting machine in a simulated factory sheet-metal cell to demonstrate coordinated inter- and intra-cell communications. Both machines used a MAP network to send and receive information from the cell-controller computer, and to coordinate cell operation. The methodology, hardware and software required to adapt the ASEA robot to the MAP network are described. This methodology will be useful in adapting other computer-controlled manufacturing devices to MAP networks.     

Protein structure alignment by incremental combinatorial extension (CE) of the optimal path

A new algorithm is reported which builds an alignment between two proteinstructures. The algorithm involves a combinatorial extension (CE) of analignment path defined by aligned fragment pairs (AFPs) rather than themore conventional techniques using dynamic programming and Monte Carlooptimization. AFPs, as the name suggests, are pairs of fragments, one fromeach protein, which confer structure similarity. AFPs are based on localgeometry, rather than global features such as orientation of secondarystructures and overall topology. Combinations of AFPs that representpossible continuous alignment paths are selectively extended or discardedthereby leading to a single optimal alignment. The algorithm is fast andaccurate in finding an optimal structure alignment and hence suitable fordatabase scanning and detailed analysis of large protein families. Themethod has been tested and compared with results from Dali and VAST using arepresentative sample of similar structures. Several new structuralsimilarities not detected by these other methods are reported. Specificone-on-one alignments and searches against all structures as found in theProtein Data Bank (PDB) can be performed via the Web athttp://cl.sdsc.edu/ce.html.     

Model selection for covariance structures analysis in nursing research

Covariance structures analysis is often used in nursing research to appraise statistical models reflecting complex human health processes. The model selection approach in covariance structures analysis is designed to select the "best" model from a specified set of theoretically defensible, competing alternatives, all of which are viewed as approximations. Model selection criteria explicitly incorporate both model misfit in the population and sampling error to evaluate the set of models. The result is that interpretability of model parameters and goodness-of-fit are enhanced simultaneously. Relative merits of the model selection approach are identified in light of technical concerns, parsimony, and use of scientific theory in nursing.     

The stretch zone of automotive steel sheets

The paper deals with an experimental determination of the stretch zone dimensions in the notch tip in thin steel sheets. The stretch zone dimensions depend on steel grade, on the rolling direction as well as on the loading rate. Stretch zones were observed and measured on three steel grades. Fracture area and stretch zones were analysed by SEM. Stable crack growth was monitored by videoextensometry techniques on CT (Compact Tension) specimens. Specimens were loaded under two loading rates by eccentric tension, whereby the deformation in the notch surrounding area was recorded using a non-contact measurement–videoextensometry technique. Linear relation between the stretch zone dimensions was determined.     

Dynamic simulation and experimental evaluation of EPDM terpolymerization with vanadium-based catalyst

The development of a simplified kinetic model describing some effects observed in catalyzed olefin terpolymerization is presented. Based on the method of moments, the model describes the influence of Al/V ratio and diene concentration on reaction yield and on polymer characteristics such as molecular weight, ethylene incorporation, and polydispersity. In order to verify the model validity, the terpolymerization reactions were performed using VOCl₃–Al₂Et₃Cl₃ systems and 2-ethylidenebi-cyclo[2.2.1]hept-5-ene (ENB) as diene. The results of dynamic simulation fit well the experimental data for Al/V up to 15, but the model fails under high diene concentration, where branching reactions, neglected by reason of simplification, become significant. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1173–1189, 1998     

Mesoporous Cr2O3 as negative electrode in lithium batteries: TEM study of the texture effect on the polymeric layer formation

Mesoporous single crystal (PSC) oxides have been reported as presenting higher electrochemical performances than bulk materials in lithium ion batteries operating via intercalation processes. Here, we extend this study to the electrochemical behaviour of mesoporous Cr₂O₃ versus Li⁺/Li⁰. We confirm that the Cr₂O₃ reacts towards Li through a conversion reaction mechanism leading, upon discharge, to the formation of large metallic chromium nanoparticles (10 nm); the latter are embedded into a Li₂O matrix together with, in this specific case, a copious amount of polymeric materials coming from electrolyte degradation, surrounding the particles, and filling the pores. During the following charge, re-oxidation of the nanoparticles occurs with the formation of CrO_1−x, with the main difference, as opposed to bulk Cr₂O₃ electrodes, being the preservation of the polymeric layer at the end of the charge. We believe the material mesoporosity, via capillary effects, to be at the origin of such a difference. These electrolyte degradation products are shown to help in maintaining the material mesoporosity for a great number of cycles; and interestingly they are not detrimental to the cell performance in terms of capacity retention while presenting great advantages in terms of charge transfer by reducing diffusion lengths, namely for Li⁺ ions. The positive attributes of mesoporous material-based electrodes noticed for insertion reactions can then be extended to conversion reaction electrodes as long as we can master their synthesis while controlling their mesoporosity through either soft or hard templating techniques.     

Near-optimal parameterization of the intersection of quadrics: III. Parameterizing singular intersections

We conclude, in this third part, the presentation of an algorithm for computing an exact and proper parameterization of the intersection of two quadrics. The coordinate functions of the parameterizations in projective space are polynomial, whenever it is possible. They are also near-optimal in the sense that the number of distinct square roots appearing in the coefficients of these functions is minimal except in a small number of cases (characterized by the real type of the intersection) where there may be an extra square root.     

环氧树脂涂料用脂肪族二胺加成物固化剂

介绍了一类性能独特的脂肪族和脂环族二胺加成物环氧固化剂,其毒性低、气味小。用其制备的涂料具有良好的耐化学腐蚀性、高硬度和良好的光泽性。