Non-invasive measurement of cholesterol in human blood by impedance technique: an investigation by 2D finite element field modelling

This paper concerns detection of solid particles suspended in conductive media by impedance technique. The technique is based on changes in impedance measured between two electrodes placed across a given volume of conducting medium. It presents a methodology for modelling and investigation of the feasibility of such a technique for particle detection by 2D finite element (FE) field modelling. This is based on modelling and computation of electric field distribution between the above electrodes. It establishes the modelling approach, the complexity involved and justifies the need for modelling in 3D to incorporate some of the effects that cannot be taken into account in 2D models. It reports on the modelling investigation for a specific case of detecting, by impedance technique cholesterol particles suspended in human blood and points to a possible instrument for non-invasive measurement of blood cholesterol level

Uncertainty quantification for kinetic models in socio-economic and life sciences

Kinetic equations play a major rule in modeling large systems of interacting particles. Recently the legacy of classical kinetic theory found novel applications in socio-economic and life sciences, where processes characterized by large groups of agents exhibit spontaneous emergence of social structures. Well-known examples are the formation of clusters in opinion dynamics, the appearance of inequalities in wealth distributions, flocking and milling behaviors in swarming models, synchronization phenomena in biological systems and lane formation in pedestrian traffic. The construction of kinetic models describing the above processes, however, has to face the difficulty of the lack of fundamental principles since physical forces are replaced by empirical social forces. These empirical forces are typically constructed with the aim to reproduce qualitatively the observed system behaviors, like the emergence of social structures, and are at best known in terms of statistical information of the modeling parameters. For this reason the presence of random inputs characterizing the parameters uncertainty should be considered as an essential feature in the modeling process. In this survey we introduce several examples of such kinetic models, that are mathematically described by nonlinear Vlasov and Fokker--Planck equations, and present different numerical approaches for uncertainty quantification which preserve the main features of the kinetic solution.Comment: To appear in "Uncertainty Quantification for Hyperbolic and Kinetic Equations

Combined analysis of 635 patients confirms an age-related association of the serotonin 2A receptor gene with tardive dyskinesia and specificity for the non-orofacial subtype

Tardive dyskinesia (TD) is an important limiting factor in the use of typical antipsychotic drugs. Genetic variability in the serotonin 2A (5-HT2A) receptor may influence risk for TD but the results of prior studies are not confirmatory. The objective of this study was to determine association of T102C and His452Tyr polymorphisms in the 5-HT2A receptor gene (HTR2A) with TD in a large, multicentre patient sample. The design employed case-control analysis controlling for possible confounders using pooled, original data from published and available unpublished samples and employing logistic regression, analysis of variance and meta-analysis. The study sample consisted of 635 patients with schizophrenia or schizoaffective disorder (256 with TD and 379 without TD) drawn from five research centres, divided into six groups based on population origin. The main outcome measure was association of a categorical diagnosis of TD based on the Research Diagnostic Criteria for TD with HTR2A T102C and His452Tyr genotypes and haplotypes. The findings indicate significant association of TD with HTR2A T102C genotype (p = 0.002) over and above the effect of population group, also when controlling for age and gender (p = 0.0008), but not with His452Tyr genotype. The T102C genotype was significantly associated with TD in older (> median age 47 yr, p = 0.002) but not younger patients and in patients with non-orofacial (limb-truncal) (p=0.001) but not orofacial TD. By meta-analysis the Mantel-Haenszel (M-H) pooled odds ratio (OR) across all the available data was 1.64. A T102C-His452Tyr haplotype was significantly associated with TD (p = 0.0008). These findings confirm that genetic variability in HTR2A contributes a small but significant degree of risk for the expression of TD, particularly in older patients and specifically for the non-orofacial (limb-truncal) type. Together with other genetic variants associated with TD the findings could be used to assess risk in patients who are candidates for treatment with typical antipsychotic medications

LHC1: a semiconductor pixel detector readout chip with internal, tunable delay providing a binary pattern of selected events

The Omega3/LHCl pixel detector readout chip comprises a matrix of 128 X 16 readout cells of 50 mu m X 500 mu m and peripheral functions with 4 distinct modes of initialization and operation, together more than 800 000 transistors. Each cell contains a complete chain of amplifier, discriminator with adjustable threshold and fast-OR output, a globally adjustable delay with local fine-tuning, coincidence logic and memory. Every cell can be individually addressed for electrical test and masking, First results have been obtained from electrical tests of a chip without detector as well as from source measurements, The electronic noise without detector is similar to 100 e(-) rms. The lowest threshold setting is close to 2000 e(-) and non-uniformity has been measured to be better than 450 e(-) rms at 5000 e(-) threshold. A timewalk of < 10 ns and a precision of < 6 ns rms on a delay of 2 mu s have been measured. The results may be improved by further optimization

Multi-dimensional modeling and simulation of semiconductor nanophotonic devices

Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semiclassical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperature. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources