Catalytic reduction of hydrogen peroxide at metal hexacyanoferrate composite electrodes and applications in enzymatic analysis

The electrocatalytic activity of various metal hexacyanoferrates (Mhcfs) (i) immobilized on graphite electrodes, and (ii) as components of a composite electrode was investigated with respect to the reduction of hydrogen peroxide. The flow-through working electrode was a thin layer consisting of a composite of Mhcf, graphite, and polymethylmetacrylate (PMMA) as a binder, sandwiched between two Plexiglas plates. Among the pure Mhcfs immobilized on a graphite electrode, iron(III) hexacyanoferrate (Prussian blue) exhibits the highest electrocatalytic effect, whereas in the composite electrodes chromium(III) hexacyanoferrate (Crhcf) shows the highest activity and best performance and reproducibility for the electrochemical reduction of H₂O₂. The Crhcf electrode provides a linear dependence on H₂O₂ concentration in the range 2.5 × 10⁻⁶ mol L⁻¹ (LOD) to 1 × 10⁻⁴ mol L⁻¹ (phosphate buffer, pH 7). The sensor was applied for the detection of H₂O₂ enzymatically produced by glucose oxidase. The optimal conditions for the peroxide injection were 2 min after the beginning of the reaction and 25 °C with a detection limit of 7.0 × 10⁻⁶ mol L⁻¹ for glucose.     

Studies on the 12α and 26-hydroxylation of bile alcohols by rabbit liver microsomes

12α-Hydroxylation of two C₂₇-steroids by rabbit liver microsomes was studied. Optimal assay conditions were determined with 7α-hydroxy-4-cholesten-3-one and 5β-cholestane-3α,7α-diol as substrates. The rate of 12α-hydroxylation of 7α-hydroxy-4-cholesten-3-one was found to be greater than that of 5β-cholestane-3α,7α-diol by ca. 60%. Microsomal 26-hydroxylation of 5β-cholestane-3α7α-diol was also measured, and the ratio of 26-hydroxylation to 12α-hydroxylation of 5β-cholestane-3α,7α-diol was found to be ca. 0.4. Rabbit liver 12-αhydroxylase was more active than that of three other species (man, rat, monkey), explaining in part the predominance of cholic acid in rabbit bile.     

Morphological organization of the dorsal protuberance of Linepithema humile (Mayr, 1868) ant's larvae (Hymenoptera, Formicidae)

The Argentine ant Linepithema humile is an important invasive species because of the levels of infestation that it can reach; however, there is little information about its presence, histological organization, and function of the dorsal protuberance, which is found exclusively in their larvae. The objective of this study was to describe it in L. humile through scanning electron microscopy and transmission electron microscopy, bringing information about this structure. The epidermis of these larvae have cuticles covering the whole body, and is formed by a sequence of overlapping lamellas where the inner ones were thicker and presented lower electron density, whereas the outer ones were thinner and highly electron dense. Pores or pore-like channels were not observed. A thick and acellular region composed of granular material was found under the cuticular layer. Out of this region, the flattened epidermic cells formed an epithelial layer. For the dorsal protuberance region, these cells become prismatic, and similarly to the cuticle, presents significant thickening. These cells presented extended microvilli, as well as a great amount of lamellar rough endoplasmic reticulum. Under this epithelium was observed a concentration of fat body cells, more numerous in the dorsal protuberance region. This study indicated that the dorsal protuberance present in the first segment of L. humile larvae has apparently no secretory function because no pores were found. This fact allowed to conclude that in L. humile larvae the dorsal protuberance would have the function to make it easier for the worker ants to carry them within the colony.     

Stereo cloud‐top height retrieval with ASTER and MISR

The combined multi‐view photogrammetric retrieval of cloud‐top height (CTH) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Multi‐angle Imaging SpectroRadiometer (MISR) is discussed. Although ASTER was designed mainly for land applications, the synergistic use of MISR and ASTER is shown to be valuable for 3D cloud analysis. A new cloud‐adapted matching algorithm based on least‐squares matching (LSM) was used for the photogrammetric processing of both MISR and ASTER. The methods were applied to an ASTER scene over Zürich‐Kloten, Switzerland, in April 2002, which was acquired on‐demand. This case study, with coincident ASTER, MISR and Meteosat‐6 10‐minute Rapid Scans, is treated in detail. As a matching validation option it is shown that, by chance, the cloud motion error for the MISR An‐Aa and ASTER stereo CTHs is approximately the same, independent of the actual cloud height and cloud motion. It was therefore possible to evaluate the accuracy of the MISR An‐Aa matching versus the ASTER matching, independent of artefacts due to the subsequent wind correction. The results were also compared to the operational MISR L2TC stereo CTH results. The results obtained by each of these methods yield consistent values for CTH (uncorrected for wind motion).     

Combining mapping and partitioning exploration for NoC-based embedded systems

Networks on Chip (NoC) have emerged as the key paradigm for designing a scalable communication infrastructure for future Systems on Chip (SoC). An important issue in NoC design is how to map an application on this architecture and how to determine the hardware/software partition that satisfies the performance, cost and flexibility requirements. In this paper, we propose an approach that concurrently optimizes the mapping and the partitioning of streaming applications. The proposed approach exploits multiobjective evolutionary algorithms that are fed by execution performances scores corresponding to the evaluated mappings and partitioning ability to pipeline execution of the streaming application. As result, most promising solutions are highlighted for mapping multimedia applications onto a SoC architecture interconnecting 16 nodes through 2D-Mesh and Ring NoC.     

Understanding dendritic cell biology and its role in immunological disorders through proteomic profiling

Dendritic cells (DC) have always been present on the bright spot of immune research. They have been extensively studied for the last 35 years, and much is known about their different phenotypes, stimulatory capacity, and role in the immune system. During the last 15 years, great attention has been given to studies on global gene and protein expression profiles during the differentiation and maturation processes of these cells. It is well understood that studying the proteome, together with information on the role of protein post-translational modifications (PTM), will reveal the real dynamics of a living cell. The rapid increase of proteomic studies during the last decade describing the differentiation and maturation process in DCs, as well as modifications brought by the use of different compounds that either increase or decrease their immunogenicity, reflects the importance of understanding the molecular processes behind the functional properties of these cells. In the present review, we will give an overview of proteomic studies focusing on DCs. Thereby we will concentrate on the importance of these studies in understanding DC behavior from a molecular point of view and how these findings have aided in understanding the differences in functional properties of these cells.     

Minimization of Sewage Network Overflow

We are interested in the optimal control of sewage networks. It is of high public interest to minimize the overflow of sewage onto the streets and to the natural environment that may occur during periods of heavy rain. The assumption of linear flow in a discrete time setting has proven to be adequate for the practical control of larger systems. However, the possibility of overflow introduces a nonlinear and nondifferentiable element to the formulation, by means of a maximum of linear terms. This particular challenge can be addressed by smoothing methods that result in a nonlinear program (NLP) or by logical constraints that result in a mixed integer linear program (MILP). We discuss both approaches and present a novel tailored branch-and-bound algorithm that outperforms competing methods from the literature for a set of realistic rain scenarios.     

MIGA, A Software Tool for Nonlinear System Modelling with Modular Neural Networks

This paper presents a software tool suitable for dynamic system modelling. The models generated by this tool are modular neural networks, see [1]. Each module behaves like a functional block and is connected to the other modules like in classical block diagrams. This tool allows the inclusion of a priori knowledge and, furthermore, to extract physical information from the models, once the system has learned. The modelling tool is capable of automatic model generation, parameter estimation and model validation.     

Excluded volume effect in polyacrylonitrile solutions

Summary The paper discusses the validity criteria of the theories on the excluded volume effect for high molecular weight (Z) polyacrylonitrile. The experimental data obtained for both the interpenetration function (Z) and the hydrodynamic function II(Z) satisfactorily approach the theoretical predictions of the renormalized two-parameter theory for high excluded volume.