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This paper describes a novel colorimetric method for detection of nucleic acid targets in a homogeneous format with improved sensitivity by means of a system based on the combination of a tunable monochromatic light source and an amorphous/nanocrystalline silicon photodetector that detects color and light intensity changes undergone by samples/assays containing tailored gold nanoparticles probes. This new low cost, portable, fast and simple optoelectronic platform, with the possibility to be re-used, permits detection of at least 400 fentomole of specific DNA sequences without target or signal amplification and was applied to the rapid detection of human pathogens in large variety of clinical samples such as Mycobacterium tuberculosis. © 2008 Elsevier B.V. All rights reserved.

ZnO films were grown on sapphire (001) substrate by atmospheric MOCVD using diethyl zinc and tertiary butanol precursors. The influence of different carrier gases (H2 and He) on the properties was analyzed by their structural (XRD), microstructural (SEM) and compositional (SIMS) characterization. The intensity of the strongest diffraction peak from ZnO (002) plane was increased by about 2 orders of magnitude when He is used as carrier gas, indicating the significant enhancement in crystallinity. The surface of the samples grown using H2 and He carrier gases was composed of leaf-like and spherical grains respectively. Hydrogen [H] content in the film grown using H2 is higher than that using He, indicating that the [H] was influenced by the H2 carrier gas. Ultraviolet emission dominates the low temperature PL spectra. The emission from ZnO films grown using He show higher optical quality and more emission centers.

Transparent conductive oxides (TCOs) such as indium tin oxide (ITO) thin films onto glass substrates are widely used as transparent and conductive electrodes for a variety of technological applications including flat panel displays, solar cells, smart windows, touch screens, etc. ITO films on glass and polycarbonate (PC) substrates were prepared at room temperature (RT) and at different PO2. The films were characterized in terms of the surface roughness (δ), sheet resistance, the refractive index (n) and extinction coefficient (k). The free carrier density (nc) and the carrier mobility (μ) of the ITO (In2O3:Sn) films were measured and studied. The nc and μ values vary in different ratio of oxygen partial pressure (PO2) of ITO deposition. The observed changes in the ITO film resistivity are due to the combined effect of different parameter values for nc and μ. From AFM analysis and spectra calculations, the surface roughness values of the ITO films were studied and it was observed that the δ values were lower than 15 nm. The energy band gap Eg ranges from 3.26 eV to 3.66 eV as determined from the absorption spectrum. It was observed an increase on the energy band gap as the PO2 decrease in the range of 20-2% PO2. The Lorentz oscillator classical model has also been used to fit the ellipsometric spectra in order to obtain both refractive index n and extinction coefficient κ values. © 2008 Elsevier Ltd. All rights reserved.

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In the present work, we investigate the influence of hydrocarbon (CHx) thin film coating on porous silicon (PS) by plasma enhanced chemical vapor deposition (PECVD) technique to detect CO2 gas. The fabricated CHx/PS heterojunction device shows up to one and two orders of magnitude enhancement in current under CO2 gas exposure. FTIR spectroscopy measurements reveal a remarkable structural modification of the CHx/PS device during CO2 gas exposure. Further, the enhancement of CHx related absorbance bands by a factor 6.2 for the CHx/PS specimen in comparison with PS confirm the good quality of the deposited CHx thin films. © 2007 Elsevier B.V. All rights reserved.

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Abstract.  Total ionization cross sections of neutral phosphorus, arsenic, antimony, and bismuth atoms by electron impact are reported and compared to the only available experimental results by Freund et al. [Phys. Rev. A 41, 3575 (1990)]. These calculations take into account the possibilities that some target atoms used in the experiments were in metastable states close to the ground state, the excitation-autoionization of nsnp4 excited states may be substantial, and the ions produced in experiments may be in excited, low-lying metastable states. The cross sections for direct ionization calculations are based on the BEB model by Kim and Rudd [Phys. Rev. A 50, 3954 (1994)]. Plane-wave Born cross sections scaled by the method developed by Kim [Phys. Rev. A 64, 3954 032713 (2001)] are used to determine the contributions from excitation-autoionization. The combination of the BEB model and the scaled Born cross sections is in agreement with the experimental data by Freund et al. These theoretical data are useful to experimentalists and can be used to complete data tables needed for plasma or astrophysical studies.

Abstract.  Total ionization cross sections of neutral phosphorus, arsenic, antimony, and bismuth atoms by electron impact are reported and compared to the only available experimental results by Freund et al. [Phys. Rev. A 41, 3575 (1990)]. These calculations take into account the possibilities that some target atoms used in the experiments were in metastable states close to the ground state, the excitation-autoionization of nsnp4 excited states may be substantial, and the ions produced in experiments may be in excited, low-lying metastable states. The cross sections for direct ionization calculations are based on the BEB model by Kim and Rudd [Phys. Rev. A 50, 3954 (1994)]. Plane-wave Born cross sections scaled by the method developed by Kim [Phys. Rev. A 64, 3954 032713 (2001)] are used to determine the contributions from excitation-autoionization. The combination of the BEB model and the scaled Born cross sections is in agreement with the experimental data by Freund et al. These theoretical data are useful to experimentalists and can be used to complete data tables needed for plasma or astrophysical studies.

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The WORKS Project started two years ago (2005), involving the efforts of research institutes of 13 European countries with the main purpose of improving the understanding of the major changes in work in the knowledge-based society, taking account both of global forces and the regional diversity within Europe. This research meeting in Sofia (Bulgaria) aimed to present synthetically the massive amount of data collected in the case studies (occupational and organisational) and with the quantitative research during last year.

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