Université catholique de Louvain

About: Université catholique de Louvain is a education organization based out in Louvain-la-Neuve, Belgium. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 25319 authors who have published 57360 publications receiving 2172080 citations. The organization is also known as: University of Louvain & UCLouvain.

A Practical Implementation of the Timing Attack

Abstract: When the running time of a cryptographic algorithm is non-constant, timing measurements can leak information about the secret key. This idea, first publicly introduced by Kocher, is developed here to attack an earlier version of the CASCADE smart card. We propose several improvements on Kocher’s ideas, leading to a practical implementation that is able to break a 512-bit key in few hours, provided we are able to collect 300000 timing measurements (128-bit keys can be recovered in few seconds using a personal computer and less than 10000 samples). We therefore show that the timing attack represents an important threat against cryptosystems, which must be very seriously taken into account.

Feature extraction and selection for objective gait analysis and fall risk assessment by accelerometry

Abstract: Falls in the elderly is nowadays a major concern because of their consequences on elderly general health and moral states. Moreover, the aging of the population and the increasing life expectancy make the prediction of falls more and more important. The analysis presented in this article makes a first step in this direction providing a way to analyze gait and classify hospitalized elderly fallers and non-faller. This tool, based on an accelerometer network and signal processing, gives objective informations about the gait and does not need any special gait laboratory as optical analysis do. The tool is also simple to use by a non expert and can therefore be widely used on a large set of patients.

Increased susceptibility of EDL muscles from mdx mice to damage induced by contractions with stretch.

Abstract: Absence of dystrophin in mdx muscles may render the muscle more susceptible to damage when submitted to high stress levels. To test this, typically slow (soleus) and fast (EDL) limb muscles of dystrophic (mdx) and normal (C57BL/10) mice were submitted (in vitro) to a series of isometric contractions, followed by a series of contractions with stretches. Muscle injury was assessed by monitoring the force signal. Membrane damage was evaluated by bathing the muscle in Procion Red, a dye that does not penetrate intact fibres, and subsequent analysis by light microscopy. After isometric contractions, only a very small force drop (< 3% of maximal isometric force) was observed which indicated that no injury had occurred in soleus and EDL muscles in either mdx or C57 strains. After contractions with a stretch, a force drop of 10% was observed in soleus muscles from both strains and in EDL muscles from C57 mice. However, in mdx mice EDL muscles displayed an irreversible force drop of 40-60%. Histological analysis of the muscles indicates that force drop is associated with membrane damage. These results show that EDL muscles from mdx mice are more vulnerable than their controls, supporting the structural role hypothesis for dystrophin. Furthermore, they suggest that contractions with stretches may contribute to the muscle damage and degeneration observed in DMD-patients.

Control of liver cell fate decision by a gradient of TGFβ signaling modulated by Onecut transcription factors

Abstract: During liver development, hepatocytes and biliary cells differentiate from common progenitors called hepatoblasts. The factors that control hepatoblast fate decision are unknown. Here we report that a gradient of activin/TGFbeta signaling controls hepatoblast differentiation. High activin/TGFbeta signaling is required near the portal vein for differentiation of biliary cells. The Onecut transcription factors HNF-6 and OC-2 inhibit activin/TGFbeta signaling in the parenchyma, and this allows normal hepatocyte differentiation. In the absence of Onecut factors, the shape of the activin/TGFbeta gradient is perturbed and the hepatoblasts differentiate into hybrid cells that display characteristics of both hepatocytes and biliary cells. Thus, a gradient of activin/TGFbeta signaling modulated by Onecut factors is required to segregate the hepatocytic and the biliary lineages.

Density of Demodex-folliculorum in Rosacea - a Case-control Study Using Standardized Skin-surface Biopsy

Abstract: A standardized skin-surface biopsy (1 cm2) of the cheek was performed in 49 patients with rosacea [13 with erythematotelangiectatic rosacea (ETR), three with squamous rosacea (SR), 33 with papulopustular rosacea (PPR)], and 45 controls. A mean density of 0.7 Demodex folliculorum/cm2 was found in controls, 98% of whom had less than five Demodex/cm2. When all clinical types of rosacea were considered collectively, the density of Demodex was significantly higher in patients with rosacea than in controls (mean = 10.8/cm2; P < 0.001). When the various clinical types of rosacea were considered separately, Demodex density was statistically significantly higher than in controls only in the PPR patients (mean = 12.8/cm2; P < 0.001). The same type of comparison was also made for three other groups of subjects-patients with isolated inflammatory papules (n = 4), rhinophyma (n = 3), and HIV infection (n = 21), respectively: in these groups, the Demodex density did not differ significantly from controls. The present study demonstrates a high density of D. folliculorum in PPR, and supports its pathogenic role in the papulopustular phase of rosacea. The study suggests that standardized surface biopsy could be a useful diagnostic tool for PPR, with a 98% specificity when Demodex density is higher than 5/cm2.