Homogeneous versus heterogeneous catalytic reactions to eliminate organics from waste water using H2O2

Homogeneous (Cu²⁺ ions) and heterogeneous (Cu²⁺-pillared clay) Fenton-like catalysts have been compared in the conversion of p-coumaric acid. The performances of the two classes of catalysts are similar for an analogous amount of copper, but there are some relevant differences in terms of (i) the presence of an induction time, (ii) the turnover frequency, (iii) the efficiency in the use of H₂O₂, (iv) the initial attack of p-coumaric acid (hydroxylation on the aromatic ring or oxidative attack on the double bond of the lateral chain), and (v) the effect of dissolved oxygen on the removal of total organic carbon (TOC). These differences were interpreted in terms of reaction network of generation of radical oxygen species and of organics conversion. The possible formation of a surface peroxo adduct coordinated to a copper binulcear site was also evidenced for the solid heterogeneous catalyst.     

Catalytic activity of dispersed CuO phases towards nitrogen oxides (N2O, NO, and NO2)

A systematic reactivity study of N₂O, NO, and NO₂ on highly dispersed CuO phases over modified silica supports (SiO₂–Al₂O₃, SiO₂–TiO₂, and SiO₂–ZrO₂) has been performed. Different reaction paths for the nitrogen oxide species abatement were studied: from direct decomposition (N₂O) to selective reductions by hydrocarbons (N₂O, NO, and NO₂) and oxidation (NO to NO₂). The oxygen concentration, temperature, and contact time, were varied within suitable ranges in order to investigate the activity and in particular the selectivity in the different reactions studied. The support deeply influenced the catalytic properties of the active copper phase. The most acidic supports, SiO₂–Al₂O₃ and SiO₂–ZrO₂, led to a better activity and selectivity of CuO for the reactions of N₂O, NO, and NO₂ reductions and N₂O decomposition than SiO₂–TiO₂. The catalytic results are discussed in terms of actual turnover frequencies starting from the knowledge of the copper dispersion values.     

The phase behavior,mechanical, and rheological characteristics of blends containing nitrile polymers and poly(ethylene-co-maleic anhydride)

The phase behavior of binary blends of acrylonitrile/methyl acrylate/butadiene terpolymer (B210) and poly(ethylene-co-maleic anhydride) (PEMA) was examined based on thermal analysis and optical microscopy. Miscibility of these polymer blends was recognized over a wide range of compositions. The appearance of phase separation during subsequent heatings above the glass transition temperature (T_g) of these blends was associated with a lower critical solution temperature (LCST) behavior. Rheological characteristics such as shear storage modulus (G′), loss modulus (G″) and complex viscosity have been shown to depend on the amount of PEMA in the blend. Mechanical properties including the tensile strength and flexural modulus also were found to be related to the composition of the blend. © 1993 John Wiley & Sons, Inc.     

Motif patterns in 2D

Motif patterns consisting of sequences of intermixed solid and don’t-care characters have been introduced and studied in connection with pattern discovery problems of computational biology and other domains. In order to alleviate the exponential growth of such motifs, notions of maximal saturation and irredundancy have been formulated, whereby more or less compact subsets of the set of all motifs can be extracted, that are capable of expressing all others by suitable combinations. In this paper, we introduce the notion of maximal irredundant motifs in a two-dimensional array and develop initial properties and a combinatorial argument that poses a linear bound on the total number of such motifs. The remainder of the paper presents approaches to the discovery of irredundant motifs both by offline and incremental algorithms.     

Measuring the structural similarity among XML documents and DTDs

Measuring the structural similarity between an XML document and a DTD has many relevant applications that range from document classification and approximate structural queries on XML documents to selective dissemination of XML documents and document protection. The problem is harder than measuring structural similarity among documents, because a DTD can be considered as a generator of documents. Thus, the problem is to evaluate the similarity between a document and a set of documents. An effective structural similarity measure should face different requirements that range from considering the presence and absence of required elements, as well as the structure and level of the missing and extra elements to vocabulary discrepancies due to the use of synonymous or syntactically similar tags. In the paper, starting from these requirements, we provide a definition of the measure and present an algorithm for matching a document against a DTD to obtain their structural similarity. Finally, experimental results to assess the effectiveness of the approach are presented.     

Spray-Coating of Superhydrophobic Coatings for Advanced Applications

Superhydrophobic coatings are widely applicable, e.g., as self-cleaning surfaces or water–oil separation membranes, yet their wider usage is impeded due to costs of fabrication, size, or substrate limitation. Spray-coating is a versatile coating procedures and might offer a good solution for the fabrication of these superhydrophobic coatings, due to the fact that coatings can be fabricated on various materials in a simple, fast, and inexpensive manner. Most procedures rely on hybrid coatings of hydrophobized nanoparticles and a polymeric matrix, which have several drawbacks including the easy loss of nanoparticles and difficult waste handling. Here, the fabrication of the superhydrophobic material, called Fluoropor, for the first time, by spray-coating on various substrates including metals, tissues, concrete, and glass is presented. It is fabricated by spray-coating a mixture of a highly fluorinated monomer blended with porogens followed by photopolymerization. The superhydrophobicity of the material relies on the porous structure on the micro-/nanoscale across the bulk material and does not require any nanoparticles. Excellent self-cleaning ability of these coatings, resistance against thermal and abrasive impact, and their application as oil–water separation membranes are shown. This versatile applicability is highly promising for real-world application as self-cleaning coatings or oil–water separating membranes.     

Microfluidic device with dual-channel fluorescence acquisition for quantification/identification of cancer cells

This paper presents an optofluidic device for cell discrimination with two independent interrogation regions. Pumping light is coupled to the device, and cell fluorescence is extracted from the two interrogation zones by using optical fibers embedded in the optofluidic chip. To test the reliability of this device, AU-565 cells—expressing EpCAM and HER2 receptors—and RAMOS cells were mixed in a controlled manner, confined inside a hydrodynamic focused flow in the microfluidic chip and detected individually so that they could be discriminated as positive (signal reception from fluorescently labeled antibodies from the AU-565 cells) or negative events (RAMOS cells). A correlation analysis of the two signals reduces the influence of noise on the overall data.     

Trigger inheritance and overriding in an active object databasesystem

An active database is a database in which some operations are automatically executed when specified events happen and particular conditions are met. Several systems supporting active rules in an object oriented data model have been proposed. However, several issues related to the integration of triggers with object oriented modeling concepts have not been satisfactorily addressed. We discuss issues related to trigger inheritance and refinement in the context of the Chimera active object oriented data model. In particular, we introduce a semantics for an active object language that takes into account trigger inheritance and supports trigger overriding. Moreover, we state conditions on trigger overriding ensuring that trigger semantics is preserved in subclasses     

Redox-flexible NADH oxidase biosensor: A platform for various dehydrogenase bioassays and biosensors

A generic amperometric bioassay based on the enzymatic oxidation catalysed by the stable NADH oxidase (NAox) from Thermus thermophilus has been developed for NADH measurements. The NAox uses O₂ as its natural electron acceptor and produces H₂O₂ in a two-electron process. Electrochemical and spectrophotometric experiments showed that the NAox used in this work, presents a very good activity towards its substrate and, in contrary to previously mentioned NADH oxidases, does not require the addition of any exogenous flavin cofactor neither to promote nor to maintain its activity. In addition, the NAox used also works with artificial electron acceptors like ferrocene derivatives. O₂ was successfully replaced by redox mediators such as hydroxymethyl ferrocene (FcCH₂OH) for the regeneration of the active enzyme. Combining the NAox with the mediator and the horseradish peroxidase we developed an original, high sensitive “redox-flexible” NADH amperometric bioassay working in a large window of applied potentials in both oxidation and reduction modes. The biosensor has a continuous and complementary linearity range permitting to measure NADH concentrations starting from 5 × 10⁻⁶ M in reduction until 2 × 10³ M in oxidation. This redox-flexibility allows choosing the applied potential in order to avoid electrochemical interferences. The association of the “redox-flexible” concept with NADH dependent enzymes opens a novel strategy for dehydrogenases based bioassays and biosensors. The great number of dehydrogenases available makes the concept applicable for numerous substrates to analyse. Moreover it allows the development of a wide range of biosensors on the basis of a generic platform. This gives several advantages over the previous manufacturing techniques and offers a general and flexible scheme for the fabrication of biosensors presenting high sensitivities, wide calibration ranges and less affected by electrochemical interferences.     

Innovation at the end of the life cycle: discontinuous innovation strategies by incumbents

This paper focuses on the strategies of incumbents that seek to develop discontinuous innovations within the boundaries of a mature innovation system. Mature innovation systems do not provide support for these discontinuous innovations. This article focuses on exploring why incumbents in these setting engage in discontinuous innovation and what strategies they deploy to become successful. We analyse 10 cases of incumbents developing discontinuous innovations in the mature Dutch greenhouse horticulture sector. The results of our analysis show that the incumbents are primarily triggered by dissatisfaction with the current way of doing business and that the existing institutions are the main barrier to discontinuous innovation. In response, the incumbents try to circumvent the existing innovation system in their innovation process, but when successful also engage in changing the existing innovation system. This paper contributes to the understanding of the role of incumbents as source of discontinuous innovation in mature innovation systems.