Environmental risk to health of the population

Researches of the last years in the field of ecological epidemiology and the analysis of risk for health allow to claim with confidence that the polluted environment is one of the important factors defining changes of a state of health of the population. Expert opinions on the scale of this influence differ considerably now. These estimations vary from small shares of percent to several percent, reaching in some cases 30-50%. An attempt to elaborate economic approaches to a risk assessment to health of the population has been made in this work. The main reason which demands development of special approaches for an assessment of an environmental risk is that quantitative estimation of risk for health from environmental pollution is difficult to be realized. As a rule, population is affected by the whole set of the polluting substances from the atmosphere, drinking water, food, etc. For effective risk management it is necessary to assess and compare diverse risks caused by action of various pollutants coming to an organism in different ways. The stated methodical materials give an idea of possibility of the stage-by-stage multilevel risk analysis at the solution of environmental problems. Further comparative analysis connected with definition and comparison of various dangers can be done by means of the results received at a risk evaluation stage. © 2016 Anopchenko et al

Biosensing platform combining label-free and labelled analysis using Bloch surface waves

Bloch surface waves (BSW) propagating at the boundary of truncated photonic crystals (1D-PC) have emerged as an attractive approach for label-free sensing in plasmon-like sensor configurations. Due to the very low losses in such dielectric thin film stacks, BSW feature very low angular resonance widths compared to the surface plasmon resonance (SPR) case. Besides label-free operation, the large field enhancement and the absence of quenching allow utilizing BSW coupled fluorescence detection to additionally sense the presence of fluorescent labels. This approach can be adapted to the case of angularly resolved resonance detection, thus giving rise to a combined label-free / labelled biosensor platform. It features a parallel analysis of multiple spots arranged as a one-dimensional array inside a microfluidic channel of a disposable chip. Application of such a combined biosensing approach to the detection of the Angiopoietin-2 cancer biomarker in buffer solutions is reported

Erbium implanted silicon rich oxide thin films suitable for slot waveguides applications

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Electrical behavior of MIS devices based on Si nanoclusters embedded in SiOxNy and SiO2 films

We examined and compared the electrical properties of silica (SiO2) and silicon oxynitride (SiOxNy) layers embedding silicon nanoclusters (Sinc) integrated in metal-insulator-semiconductor (MIS) devices. The technique used for the deposition of such layers is the reactive magnetron sputtering of a pure SiO2 target under a mixture of hydrogen/argon plasma in which nitrogen is incorporated in the case of SiOxNy layer. Al/SiOxNy-Sinc/p-Si and Al/SiO2-Sinc/p-Si devices were fabricated and electrically characterized. Results showed a high rectification ratio (>104) for the SiOxNy-based device and a resistive behavior when nitrogen was not incorporating (SiO2-based device). For rectifier devices, the ideality factor depends on the SiOxNy layer thickness. The conduction mechanisms of both MIS diode structures were studied by analyzing thermal and bias dependences of the carriers transport in relation with the nitrogen content

1.54 μm Er doped light emitting devices: Role of silicon content

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Engineering silicon nanocomposites for efficient light emitting diodes

We will discuss few perspective directions in engineering and optimization of Er-doped and undoped Si nanocomposites to develop efficient light-emitting diodes for infrared and visible light applications, respectively

Erbium implanted silicon rich oxide thin films suitable for slot waveguides applications

Thin (50 nm) erbium implanted silicon rich oxide films suitable for slot waveguides applications have been produced and studied by means of optical spectroscopy and structural characterisation techniques. Comparison between different deposition techniques in terms of light emitting properties of erbium ions is presented. Special attention is given to the efficiency improvement of the energy transfer from silicon nanoclusters to erbium ions where the type of annealing treatment is proven to be of crucial importance

Low dimensional silicon to enable silicon photonics

In this chapter we will review the photonic applications of nanos- tructured silicon. As we change the dimensionality of silicon very fasci- nating and new optical properties of the material appear. In particular, light emission starts to be a very e\ub1cient process in nanostructured silicon and light emitting diodes with e\ub1ciency in excess of 1% have been fabricated. Optical ampli\uafcation has been also observed when silicon nanocrystals are embed into a dielectric matrix. In addition to electronic property variations, nanostructured silicon can be also used as a nanodielectric material. Some examples will be discussed where photonic Bloch oscillations, photonic Zener tunnelling and high quality microcavities are demonstrated

Polarization strategies to improve the emission of Si-based light sources emitting at 1.55 um

We present a electroluminescence (EL) study of the Si-rich silicon oxide (SRSO) LEDs with and without Er3+ ions under different polarization schemes: direct current (DC) and pulsed voltage (PV). The power efficiency of the devices and their main optical limitations are presented. We show that under PV polarization scheme, the devices achieve one order of magnitude superior performance in comparison with DC. Time-resolved measurements have shown that this enhancement is met only for active layers in which annealing temperature is high enough (>1000 ◦C) for silicon nanocrystal (Si-nc) formation. Modeling of the system with rate equations has been done and excitation cross-sections for both Si-nc and Er3+ ions have been extracted

Effect of the annealing treatments on the transport and electroluminescence properties of SiO2 layers doped with Er and Si nanoclusters

We studied the effect of rapid thermal processing and furnace annealing on the transport properties and electroluminescence (EL) of SiO2 layers doped with Si and Er ions. The results show that for the same annealing temperature, furnace annealing decreases the electrical conductivity and increases the probability of impact excitation, which leads to an improved external quantum efficiency. Correlations between predictions from phenomenological transport models, annealing regimes and erbium EL are observed and discusse