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Nanotechnology is having a positive impact on nearly every industry, and in particular in healthcare, where it is extending the limits of molecular diagnostics to the nanoscale-nanodiagnostics. Here we describe an innovative optoelectronic platform for the colorimetric detection of nucleic acids based on oligonucleotide-derivatized gold nanoparticles. The device integrates an amorphous/nanocrystalline biosensor and a light emission source with a gold nanoprobe for specific DNA detection. This low cost, fast and simple optoelectronic platform permits detection of few picomole of nucleic acid without target or signal amplification making it suitable for application in population diagnostics and in point-of-care hand-held devices. © 2007 Elsevier B.V. All rights reserved.

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This paper presents an analytical model for CMOS delay and power estimation in deep sub micrometer technologies. In this paper the EKV transistor model is considered as a way of granting the accuracy of results in the characterization of deep submicron CMOS circuits. The analytical model proposed is valid for a ramp input signal, and takes into account all the operation regions of the transistor as well the influence of the gate-to-drain capacitance. For estimating the power consumption, a simple numerical integration process is applied to the current wave. An application example considering the use of the model for the evaluation of the delay and power consumption associated to a CMOS inverter is considered. The validity of the results obtained with the proposed model for a 1.2V TSMCN65 CMOS inverter is checked against those obtained through Hspice simulation.

N, (N+Ga) and (N+Al) doped ZnO films were deposited on c-plane sapphire substrates by RF magnetron sputtering at room temperature. The samples were characterized by their structural, surface morphological, compositional and optical properties. The x-ray diffraction studies confirmed the co-doping of (N+Ga) and (N+Al) besides showing improvement in the crystallinity when compared with the single Ndoping. The surface of the films becomes rougher after co-doping. The x-ray photoelectron spectroscopy and Rutherford back-scattering analysis indicate that the co-doping changes the chemical states and varies the amount of nitrogen (N) in ZnO. The amount of 'N' has been greatly increased for (N+Ga) co-doping, indicating that it is the best co-doping pair for p-type ZnO. Additionally, co-doping has increased the average visible transmittance (40-650nm) and the optical band gap is shifted towards shorter wavelength. In the case of (N+Al) co-doping, the band gap becomes wider than that of undoped ZnO. © IOP Publishing Ltd.

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In this work we studied indium zinc oxide (IZO) thin films deposited by r.f. magnetron sputtering at room temperature. The films were annealed at high temperature (1100 K) in vacuum, and the oxygen exodiffusion was monitored in-situ. The results showed three main peaks, one at approximately 600 K, other at approximately 850 K and the last one at 940 K, which are probably from oxygen bonded in the film surface and in the bulk, respectively. The initial amorphous structure becomes microcrystalline, according to the X-ray diffraction. The electrical conductivity of the films decreases (about 3 orders of magnitude), after the annealing treatment. This behavior could be explained by the crystallization of the structure, which affects the transport mechanism. Apart from the changes in the material structure, a small variation was observed on the absorption coefficient. © 2007 Elsevier B.V. All rights reserved.

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There is a sustained interest both from theoretical and from practical points of view to understand the isothermal charging and the isothermal discharging currents in dielectrics. The measured currents are analyzed either in terms of polarization mechanisms or in terms of charge injection/extraction at the metal-dielectric interface and the conduction current through the dielectric material. As long as we do not know the nature of the origin of the current, it is not clear what information we can get by analyzing the experimental data. We propose to measure the open-circuit isothermal charging and discharging currents just to overpass the difficulties related to the analysis of the conduction mechanisms in dielectric materials. We demonstrate that besides a polarization current, there is a current related with charge injection or extraction at the metal-dielectric contact and a reverse current related to the charge trapped into the superficial trap states of the dielectric and that can jump at the interface in a reverse way. An analytical expression for the current is proposed. By fitting the experimental data to this analytical equation, two important parameters can be determined: (i) the highest value of the relaxation time for the polarization mechanisms still involved into the transient current and (ii) the height of the potential barrier W-0 at the metal-dielectric interface at the initial time when the step voltage is applied. The value obtained for Al-polyethylene terephthalate interface is (0.43 +/- 0.02) eV. For a charging voltage of 220 V there are 6x10(14) trapped electrons/m(2). (c) 2008 American Institute of Physics.

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Software transactional memory is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM). This paper discusses how to support revertible operations, such as memory allocation and release, within software libraries that will be used in software memory transactional contexts. The proposal is based in the extension of the transaction life cycle state diagram with new states associated to the execution of user-defined handlers. The proposed approach is evaluated in terms of functionality and performance by way of a use case study and performance tests. Results demonstrate that the proposal and its current implementation are flexible, generic and efficient

Software transactional memory (STM) is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM) locations. This paper aims at discussing how to support apparently irreversible operations within a memory transaction.

The possibility of using fly ash and shale as alternative raw materials for the production of structural ceramics was investigated. Fly ash is a by-product from coal-burning power plants, and shale is a sedimentary rock that if ground finely enough can exhibit a clay-like plasticity. Ceramic samples containing 10-50 wt% fly ash were formed from mechanical mixing of both kinds of powders that were packed and sintered in the temperature range 950-1200°C It was verified that powders with larger fly ash content exhibited lower packing density resulting in compacts with a lower sintered density. Although an increase in fly ash content was associated to a larger presence of porosity in the sintered samples, as confirmed by microstructural analysis, all studied compositions when sintered at the highest temperatures exhibited satisfactory values for water absorption (< 10%), for flexural strength (20-64 MPa) and for hardness (20-30 GPa) indicating that they have potential to be applied in the production of structural ceramics.

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Thin films of molybdenum doped indium oxide (IMO) were deposited on glass at room temperature using an in-built three-source RF magnetron sputtering. The films were studied as a function of oxygen volume percentage (O2 vol. %; ranging from 0.0 to 17.5%) in the sputtering chamber. The as-deposited amorphous films were crystallized on post-annealing. The as-deposited films are low conducting and Hall coefficients were undetectable; whereas post-annealed films possess fairly high conductivity. The lowest transmittance (11.96% at 600 nm) observed from the films deposited without oxygen increased to a maximum of 88.01% (3.5 O2 vol. %); whereas this transmittance was decreased with the increasing O2 vol. % to as low as 81.04% (15.6 O2 vol. %); a maximum of 89.80% was obtained from the films annealed at 500 °C in open air (3.5 O2 vol. %). The optical band gap of 3.80 eV obtained from the films deposited without oxygen increased with increasing O2 vol. % to as high as 3.91 eV (17.5 O2 vol. %). A maximum of 3.92 eV was obtained from the films annealed at 300 °C in N2:H2 gas atmosphere (17.5 O2 vol. %). © 2008 Elsevier Ltd. All rights reserved.