Miniaturized ionization gas sensors from single metal oxide nanowires

Gas detection experiments were performed with individual tin dioxide (SnO2) nanowires specifically configured to observe surface ion (SI) emission response towards representative analyte species. These devices were found to work at much lower temperatures (T≈280 °C) and bias voltages (V≈2 V) than their micro-counterparts, thereby demonstrating the inherent potential of individual nanostructures in building functional nanodevices. High selectivity of our miniaturized sensors emerges from the dissimilar sensing mechanisms of those typical of standard resistive-type sensors (RES). Therefore, by employing this detection principle (SI) together with RES measurements, better selectivity than that observed in standard metal oxide sensors could be demonstrated. Simplicity and specificity of the gas detection as well as low-power consumption make these single nanowire devices promising technological alternatives to overcome the major drawbacks of solid-state sensor technologies.     

Downlink capacity and interference statistics of wideband code division multiple access microcells for trains in long tunnels

The wideband code division multiple access downlink interference statistics and the capacity of equally spaced tunnel cigar-shaped microcells, used to serve users travelling in trains or metros, are analysed. The hybrid propagation model, with two defined modes, is used in the analysis. Fast fading because of multipath interference is superimposed with the main value of the loss and the slow fading up to a certain distance beyond which it can be neglected. To calculate the interference statistics and the capacity, a scenario with ten cigar-shaped microcells has been considered. The downlink capacity is then derived for different sector radii, train lengths, break point distances and propagation parameters. It is found that increasing the sector range up to 1250 m increases the sector downlink capacity. It is noticed that the maximum downlink capacity can be obtained for a sector radius of 1250-1750 m. It is also found that the increment of the propagation parameter gamma reduces the sector downlink capacity. It is also noticed that increasing the train length increases the downlink capacity. It is also found that the bend loss increases the downlink capacity and reduces the maximum sector range.     

Controls for microgrids with storage: Review,challenges, and research needs

The interest on microgrid has increased significantly triggered by the increasing demand of reliable, secure, efficient, clean, and sustainable electricity. More research and implementation of microgrid will be conducted in order to improve the maturity of microgrid technology. Among different aspects of microgrid, this paper focuses on controls of microgrid with energy storage. A comprehensive review on current control technology is given with a discussion on challenges of microgrid controls. Basic simulation results are also presented to enhance and support the analysis. Finally, research needs and roadmap for microgrid control are also described.     

Parameterization of an acousto-optic programmable dispersive filter for closed-loop learning experiments

A representation of the search space in optical pulse shaping problems employing an acousto-optic programmable dispersive filter (AOPDF) is presented for use in closed-loop learning experiments where the optimal spectral phase function to some control problem is determined by an iterative learning algorithm. The representation allows the algorithm to select a value for the optical chirp at each frequency control point such that only acoustic grating functions which preserve the spectrum of the shaped pulses are tested. The limits of this space with respect to the rate of applied optical chirp, optical bandwidth and acoustic power are examined and tested through diffraction efficiency studies performed using a commercial AOPDF. The main benefits of this representation are the elimination of undesirable frequency mixing effects, reduction of diffraction efficiency variation between arbitrary pulse shapes and faster convergence of the evolutionary algorithm.     

Combining Invariant Features and the ALV Homing Method for Autonomous Robot Navigation Based on Panoramas

Biologically inspired homing methods, such as the Average Landmark Vector, are an interesting solution for local navigation due to its simplicity. However, usually they require a modification of the environment by placing artificial landmarks in order to work reliably. In this paper we combine the Average Landmark Vector with invariant feature points automatically detected in panoramic images to overcome this limitation. The proposed approach has been evaluated first in simulation and, as promising results are found, also in two data sets of panoramas from real world environments.     

Growth factors, CD34 positive cells, and fibrin network analysis in concentrated growth factors fraction

An interesting clinical option for optimizing healing tissue is the use of platelet concentrate. Platelets contain high quantities of growth factors, among these TGF-β1 and VEGF, which are known to be implicated in tissue regeneration. CGF is produced by processing blood samples with a special centrifuge device; three layers are formed: top acellular plasma (PPP), middle CGF and bottom red blood cells (RBC) layers. Given that to date there are no data concerning the biological characteristic of CGF, the aim of this study was to evaluate the presence of TGF-β1 and VEGF in CGF and also in PPP and RBC layers. In addition, since circulating stem cells are recruited from blood to injured tissue for healing we also evaluated the presence of CD34 positive cells. Our data show the presence of TGF-β1 and VEGF in CGF and RBC layers. In addition, we show CD34 positive cells in CGF.     

Efficient sequence-specific purification of Listeria innocua mRNA species by triplex affinity capture with parallel tail-clamps

Parallel clamps can interact in a sequence-specific manner with homopyrimidine DNA and RNA oligonucleotides to form triplexes. For longer nucleic acids, we have previously demonstrated the inhibitory effect of DNA-target secondary structures on triplex formation. We further designed a modification of these molecules-that is, tail-clamps formed by addition of a tail sequence to the parallel clamp-and proved efficient binding of the molecules with structured single-stranded DNA targets. Here we explore the possible application of the tail-clamp strategy for triplex formation with RNA targets, which are typically found as strongly folded single-stranded molecules. Efficient and specific binding of a tail-clamp designed to form a parallel triplex with Listeria innocua iap mRNA sequences has been verified by UV melting curves and triplex affinity capture techniques. Furthermore, we show for the first time the formation of stable complexes of mRNA with tail-clamps not only under acidic but also under neutral and slightly basic pH conditions. These results signify a further step towards the possible applications of triplexes with mRNA molecules; research, analytical, and therapeutic uses can be envisaged. As an example, our tail-clamp-based triplex affinity capture assay allowed the specific capture and recovery of iap mRNA molecules from an L. innocua total RNA solution with 45 % yield.     

Electrochemical Synthesis of Poly(3,4-ethylenedioxythiophene) on Steel Electrodes: Properties and Characterization

Electrodeposition of poly(3,4-ethylenedioxythiophene) by electrochemical polymerization of 3,4-ethylenedioxythiophene has been performed on steel electrodes rather than on the typically used inert electrodes (Pt, Au, graphite carbon). The polymer was generated by cyclic voltammetry, chronopotentiometry and chronoamperometry from a 10 mM monomer solution in acetonitrile with 0.1 M LiClO₄. Elemental analysis of the generated polymer indicated that the monomeric units support 0.54 positive charges balanced with CIO₄ ¹⁴⁻ counterions. Electrochemical, electrical and structural properties of the prepared material have been characterized. The good adherence of films combined with its excellent properties indicate that poly(3,4-ethylenedioxythiophene) can be a suitable material for anticorrosion applications.