Antifungal Activity of Resveratrol Derivatives against Candida Species

trans-Resveratrol (1a) is a phytoalexin produced by plants in response to infections by pathogens. Its potential activity against clinically relevant opportunistic fungal pathogens has previously been poorly investigated. Evaluated herein are the candidacidal activities of oligomers (2a, 3–5) of 1a purified from Vitis vinifera grape canes and several analogues (1b–1j) of 1a obtained through semisynthesis using methylation and acetylation. Moreover, trans-ε-viniferin (2a), a dimer of 1a, was also subjected to methylation (2b) and acetylation (2c) under nonselective conditions. Neither the natural oligomers of 1a (2a, 3–5) nor the derivatives of 2a were active against Candida albicans SC5314. However, the dimethoxy resveratrol derivatives 1d and 1e exhibited antifungal activity against C. albicans with minimum inhibitory concentration (MIC) values of 29–37 μg/mL and against 11 other Candida species. Compound 1e inhibited the yeast-to-hyphae morphogenetic transition of C. albicans at 14 μg/mL

Origami voting: a non-cryptographic approach to transparent ballot verification

International audienceOver the past four decades, fear of election manipulation and hacking has spurred the security technology community to propose a variety of voting systems to implement verifiable voting. Most of these rely on hard to understand cryptographic protocols, which can affect whether users actually verify their selections. Three-Ballot and Vote/Anti-Vote/Vote, two related systems among the few non-cryptographic end-to-end verifiable voting systems, made improvements in security while eliminating complex protocols. They unfortunately suffered from usability issues, and although they did not require cryptographic primitives, they still relied on electronic devices. To address this, we introduce three folded-paper based systems that allow verifiable voting and resist common attacks despite not relying on any cryptography or electronic devices. The proposals are based on 1) semi-translucent ballots, 2) masking tape, or 3) folding and punching. These Origami voting methods help users understand the underlying mechanisms and give them a direct geometric approach to verification

A two-step target binding and selectivity support vector machines approach for virtual screening of dopamine receptor subtype-selective ligands

10.1371/journal.pone.0039076PLoS ONE76

Statistical characterization of near-wall radiative properties of a statistically non-homogeneous and anisotropic porous medium

International audienceThe radiative properties statistical characterization method of Tancrez and Taine has been extended to statistically anisotropic and non-homogeneous porous media. When a homogenized phase of such a medium does not follow Beer's law on extinction, extinction and scattering coefficients have no physical meaning: the phase is completely characterised by an extinction cumulative distribution function, a scattering cumulative probability, a general phase function and an effective optical index. A simple expression of the emission source term, in local thermal equilibrium conditions, is given for any non-homogeneous and anisotropic porous medium. The radiative transfer can be modelled by a Generalized Radiative Transfer Equation that is also extended to non-homogeneous porous media. This characterization method has been applied to the radiative properties of a packed bed of opaque and diffuse spherical particles bounded by a wall: the local porosity strongly varies near the wall and the homogenized phase is non Beerian. In the bulk of the medium, Beer's law becomes valid and extinction, absorption and scattering coefficients have been determined

Radiative transfer within strongly non homogeneous porous media: Application to a slab of packed particles

International audienceThe original radiation transfer model is dedicated to strongly non homogeneous porous media with a transparent phase and an opaque one, characterised by a diffuse reflection law at local scale. It is only based on radiative statistical functions of extinction and scattering and a general phase function, which completely characterise the radiation properties of the medium. The model is a generalisation for these media, under integral formulation, of the Generalised Radiative Transfer Equation (GRTE). A rigorous expression of the emission source term from the radiation reciprocity principle is the key point. The model is developed and applied in the case of a slab of a packed bed of spherical particles, by using a statistical Monte Carlo method. It has been validated by comparison with results of the bibliography in the academic case of purely absorbing media and in the case of optically thick slabs. The model has finally been applied to realistic cases of scattering, absorbing and emitting porous media. The model also accurately accounts for local configurations resulting in non-monotonous temperature profiles

A Two-Layer Model for the Laser Generation of Ultrasound in Graphite-Epoxy Laminates

We previously reported the performances of a numerical simulation model [1] that calculates the mechanical displacements induced within a sample by the absorption of a laser pulse. This model solves the heat diffusion and acoustic wave propagation equations over an orthotropic slab of finite thickness with the help of temporal Laplace and spatial 2D Fourier transformations. The parallel and normal displacements predicted by the model were found to be in generally very good agreement with experimental data obtained on various samples in various excitation conditions. Among these experiments, one consisted in the CO2 laser excitation of a graphite-epoxy sample. We performed an optical study of the graphite-epoxy composite using FTIR photoacoustic spectroscopy [2] to determine the optical penetration depth spectrum of this material. This study revealed that a thin (≈ 30 μm thick) epoxy layer covered the top graphite fiber sheet of the composite, and that the optical penetration depth of the CO2 radiation in the epoxy was about 20 μm. Consequently, when a CO2laser pulse impinges on the composite, all the radiation is absorbed in the epoxy layer, and it is easy to simulate this situation with the model, using the rigidity-expansion tensor [λ] of the epoxy for the generation and the rigidity tensor [C] of the composite for the propagation (see [1]).</p

Numerical and experimental studies of the generation of ultrasound by laser

We present an analytical 1-D model of the laser generation of ultrasound that takes the optical penetration effect and the time profile of the laser pulse into account. This model leads to simple expressions for the time position and width of the precursor. The results of this model are compared to experimental data. We also present numerical and experimental directivity patterns of samples having various optical penetration depths