A Key-Recovery Attack on SOBER-128

In this talk we consider linear approximations of layered cipher constructions with secret key-dependent constants that are inserted between layers, and where the layers have strong interdependency. Then clearly, averaging over the constant would clearly be wrong as it will break the interdependencies, and the Piling Up-lemma cannot be used. We show how to use linear approximations to divide the constants into constant classes, not necessary determined by a linear relation. As an example, a nonlinear filter generator SOBER-128 is considered and we show how to extend Matsui\u27s Algorithm I in this case. Also the possibility of using multiple linear approximations simultaneously is considered

An upper bound for the linearity of Exponential Welch Costas functions

AbstractThe maximum correlation between a function and affine functions is often called the linearity of the function. In this paper, we determine an upper bound for the linearity of Exponential Welch Costas functions using Fourier analysis on Zn. Exponential Welch Costas functions are bijections on Zp−1, where p is an odd prime, defined using an exponential function of Zp. Their linearity properties were recently studied by Drakakis, Requena, and McGuire (2010) [1] who conjectured that the linearity of an Exponential Welch Costas function on Zp−1 is bounded from above by O(p0.5+ϵ), where ϵ is a small constant. We prove that the linearity is upper bounded by 2πplnp+4p, which is asymptotically strictly less than what was previously conjectured

Momentum distributions of electron-positron pairs annihilating at vacancy clusters in Si

We report calculations of momentum densities of electron-positron pairs annihilating at various vacancy clusters in Si. The densities integrated along one direction, i.e., those corresponding to the spectra measured by the two-dimensional angular correlation of the annihilation radiation method, are shown to be isotropic if the positron is captured by a small vacancy cluster. The densities integrated along two directions correspond to the one-dimensional angular-correlation distribution or the Doppler-broadened annihilation radiation line shape. The characteristic narrowing of these one-dimensional distributions at vacancy clusters is demonstrated. The line-shape parameters S and W describing mainly the annihilations with valence and core electrons, respectively, are calculated and compared quantitatively with experimental data. We find a systematic increase in the S and a decrease in the W parameter as the size of the vacancy increases.Peer reviewe

Correlation effects for electron-positron momentum density in solids

A method describing the calculation of the momentum density of annihilating electron-positron pairs in solids has been developed. One-electron states, which are not perturbed by the positron, are used. The effects due to the enhancement of the electron density near the positron are taken into account by a factor depending on the electron state in the annihilating pair. This enhancement is used both for the valence and core electron states. The calculated momentum densities are in good agreement with the two-dimensional angular correlation of the annihilation radiation measurements in defect-free Cu and GaAs.Peer reviewe

Theoretical and experimental study of positron annihilation with core electrons in solids

A theory for calculating the momentum distribution of annihilating positron-electron pairs in solids is presented. To test the theory, momentum distributions are measured by the Doppler broadening of the annihilation radiation for several bulk metals and semiconductors, as well as for semiconductor alloys and for positrons trapped at vacancies in semiconductors. The theory is based on a two-particle description of the annihilating electron-positron pair. Then, the electron-positron correlation effects, i.e., the enhancement of the electron density at the positron, depend on the electronic state in question. The theory is suited for calculating the high-momentum part of the annihilation spectrum that arises from the core electrons and which can be measured by the Doppler broadening using coincidence techniques. The ideas of the theory are justified by a good agreement between theory and experiment in the case of positron annihilation in undefected bulk lattices. Moreover, the comparison of the theoretical and experimental spectra for alloys and vacancy defects tests the theoretical description for the positron distribution in delocalized and localized states, respectively.Peer reviewe

Influence of enzyme immobilization and skin-sensor interface on non-invasive glucose determination from interstitial fluid obtained by magnetohydrodynamic extraction

We integrated a magnetohydrodynamic fluid extractor with an amperometric glucose biosensor to develop a wearable device for non-invasive glucose monitoring. Reproducible fluid extraction through the skin and efficient transport of the extracted fluid to the biosensor surface are prerequisites for non-invasive glucose monitoring. We optimized the enzyme immobilization and the interface layer between the sensing device and the skin. The monitoring device was evaluated by extracting fluid through porcine skin followed by glucose detection at the biosensor. The biosensor featured a screen-printed layer of Prussian Blue that was coated with a layer containing glucose oxidase. Both physical entrapment of glucose oxidase in chitosan and tethering of glucose oxidase to electrospun nanofibers were evaluated. Binding of glucose oxidase to nanofibers under mild conditions provided a stable biosensor with analytical performance suitable for accurate detection of micromolar concentrations of glucose. Hydrogels of varying thickness (95-2000 mu m) as well as a thin (30 mu m) nanofibrous polycaprolactone mat were studied as an interface layer between the biosensor and the skin. The effect of mass transfer phenomena at the biosensor-skin interface on the analytical performance of the biosensor was evaluated. The sensing device detected glucose extracted through porcine skin with an apparent (overall) sensitivity of-0.8 mA/(M.cm(2)), compared to a sensitivity of-17 mA/(M.cm(2)) for measurement in solution. The amperometric response of the biosensor correlated with the glucose concentration in the fluid that had been extracted through porcine skin with the magnetohydrodynamic technique.Peer reviewe

Sampling of fluid through skin with magnetohydrodynamics for noninvasive glucose monitoring

Out of 463 million people currently with diabetes, 232 million remain undiagnosed. Diabetes is a threat to human health, which could be mitigated via continuous self-monitoring of glucose. In addition to blood, interstitial fluid is considered to be a representative sample for glucose monitoring, which makes it highly attractive for wearable on-body sensing. However, new technologies are needed for efficient and noninvasive sampling of interstitial fluid through the skin. In this report, we introduce the use of Lorentz force and magnetohydrodynamics to noninvasively extract dermal interstitial fluid. Using porcine skin as an ex-vivo model, we demonstrate that the extraction rate of magnetohydrodynamics is superior to that of reverse iontophoresis. This work seeks to provide a safe, effective, and noninvasive sampling method to unlock the potential of wearable sensors in needle-free continuous glucose monitoring devices that can benefit people living with diabetes.Peer reviewe

The variability of urban aerosol size distributions and optical properties in São Paulo – Brazil: new particle formation events occur at the site

Non peer reviewe

Pilot study in human healthy volunteers on the use of magnetohydrodynamics in needle-free continuous glucose monitoring

The benefits of continuous glucose monitoring (CGM) in diabetes management are extensively documented. Yet, the broader adoption of CGM systems is limited by their cost and invasiveness. Current CGM devices, requiring implantation or the use of hypodermic needles, fail to offer a convenient solution. We have demonstrated that magnetohydrodynamics (MHD) is effective at extracting dermal interstitial fluid (ISF) containing glucose, without the use of needles. Here we present the first study of ISF sampling with MHD for glucose monitoring in humans. We conducted 10 glucose tolerance tests on 5 healthy volunteers and obtained a significant correlation between the concentration of glucose in ISF samples extracted with MHD and capillary blood glucose samples. Upon calibration and time lag removal, the data indicate a Mean Absolute Relative Difference (MARD) of 12.9% and Precision Absolute Relative Difference of 13.1%. In view of these results, we discuss the potential value and limitations of MHD in needle-free glucose monitoring.Peer reviewe