Measurements and calibration method for WLAN indoor path loss modelling

International audienceFor indoor Wireless LAN systems planning, an accurate propagation modelling is required. Semi-empirical models represent an efficient approach to the coverage prediction. Based on measurement results, the model parameters are derived. In this paper we present the influence of the measurement point choice on the accuracy of the parameters estimation and thus on the model robustness

Etude du comportement rhéologique et mécanique de composites recyclés et pollués : recyclage iso fonction, rêve ou réalité ? = Study of rheological and mechanical behaviour of recycled and polluted composites : iso function recycling, dream or reality

National audienceNous étudions les effets de la pollution et du recyclage sur deux composites à matrice polypropylène. Ces effets ont été identifiés non seulement par la mesure du poids moléculaire et des propriétés rhéologiques mais aussi sur les caractéristiques mécaniques. Les polluants modèles choisis sont de l'éthylène glycol majoritairement présent dans le liquide de frein et de l'huile moteur. Ils ont été incorporés dans les composites en cours du process d'extrusion. Le recyclage a été simulé en effectuant plusieurs cycles d'extrusions successifs. Les échantillons ont été recyclés de 1 à 12 fois. Toutes ces nuances ont été testées. L'indice de fluidité, la viscosité, les propriétés en traction quasi statique ainsi que en compression dynamique ont été mesurés. Les polluants affectent davantage les propriétés rhéologiques par rapport aux propriétés mécaniques. Le recyclage thermomécanique, quant à lui, est principalement préjudiciable sur le comportement à rupture. Le résultat remarquable concerne l'effet modérateur des polluants sur la dégradation due au recyclage des propriétés des matériaux

Nucleotide diversity of the ZmPox3 maize peroxidase gene: Relationships between a MITE insertion in exon 2 and variation in forage maize digestibility

BACKGROUND: Polymorphisms were investigated within the ZmPox3 maize peroxidase gene, possibly involved in lignin biosynthesis because of its colocalization with a cluster of QTL related to lignin content and cell wall digestibility. The purpose of this study was to identify, on the basis of 37 maize lines chosen for their varying degrees of cell wall digestibility and representative of temperate regions germplasm, ZmPox3 haplotypes or individual polymorphisms possibly associated with digestibility. RESULTS: Numerous haplotypes with high diversity were identified. Frequency of nucleotide changes was high with on average one SNP every 57 bp. Nucleotide diversity was not equally distributed among site categories: the estimated π was on average eight times higher for silent sites than for non-synonymous sites. Numerous sites were in linkage disequilibrium that decayed with increasing physical distance. A zmPox3 mutant allele, carrying an insertion of a transposable element in the second exon, was found in lines derived from the early flint inbred line, F7. This element possesses many structural features of miniature inverted-repeat transposable elements (MITE). The mutant allele encodes a truncated protein lacking important functional sites. An ANOVA performed with a subset of 31 maize lines indicated that the transposable element was significantly associated with cell wall digestibility. This association was confirmed using an additional set of 25 flint lines related to F7. Moreover, RT-PCR experiments revealed a decreased amount of corresponding mRNA in plants with the MITE insertion. CONCLUSION: These results showed that ZmPox3 could possibly be involved in monolignol polymerisation, and that a deficiency in ZmPox3 peroxidase activity seemingly has a negative effect on cell wall digestibility. Also, genetic diversity analyses of ZmPox3 indicated that this peroxidase could be a relevant target for grass digestibility improvement using specific allele introgressions

Reduced skeletal muscle protein turnover and thyroid hormone metabolism in adaptive thermogenesis that facilitates body fat recovery during weight regain

Objective: The recovery of body composition after weight loss is characterized by an accelerated rate of fat recovery (preferential catch-up fat) resulting partly from an adaptive suppression of thermogenesis. Although the skeletal muscle has been implicated as an effector site for such thrifty (energy conservation) metabolism driving catch-up fat, the underlying mechanisms remain to be elucidated. We test here the hypothesis that this thrifty metabolism driving catch-up fat could reside in a reduced rate of protein turnover (an energetically costly “futile” cycle) and in altered local thyroid hormone metabolism in skeletal muscle.Methods: Using a validated rat model of semistarvation-refeeding in which catch-up fat is driven solely by suppressed thermogenesis, we measured after 1 week of refeeding in refed and control animals the following: (i) in-vivo rates of protein synthesis in hindlimb skeletal muscles using the flooding dose technique of 13C-labeled valine incorporation in muscle protein, (ii) ex-vivo muscle assay of net formation of thyroid hormone tri-iodothyronine (T3) from precursor hormone thyroxine (T4), and (iii) protein expression of skeletal muscle deiodinases (type 1, 2, and 3).Results: We show that after 1 week of calorie-controlled refeeding, the fractional protein synthesis rate was lower in skeletal muscles of refed animals than in controls (by 30–35%, p < 0.01) despite no between-group differences in the rate of skeletal muscle growth or whole-body protein deposition—thereby underscoring concomitant reductions in both protein synthesis and protein degradation rates in skeletal muscles of refed animals compared to controls. These differences in skeletal muscle protein turnover during catch-up fat were found to be independent of muscle type and fiber composition, and were associated with a slower net formation of muscle T3 from precursor hormone T4, together with increases in muscle protein expression of deiodinases which convert T4 and T3 to inactive forms.Conclusions: These results suggest that diminished skeletal muscle protein turnover, together with altered local muscle metabolism of thyroid hormones leading to diminished intracellular T3 availability, are features of the thrifty metabolism that drives the rapid restoration of the fat reserves during weight regain after caloric restriction

A first update on mapping the human genetic architecture of COVID-19

peer reviewe

n-alkanes and free fatty acids in humus and Al horizons of soils under beech, spruce and grass in the Massif-Central (Mont-Lozere), France

International audienceSoil profiles under beech, spruce and a grassland have been analysed to study the evolution of natural n-alkanes in pollution-free ecosystems. The soils had all developed on granitic bedrock, at an altitude of 1300-1500 m in the region of Mont-Lozere (southern Massif-Central, France). In contrast to the grassland soil, the two forest soils both possessed a well-developed acidic moder humus-type horizon. This could be subdivided as follows: fresh litter (OL), fragmentation (OF) and humification (OH) layers; two litters, one fresh (OL1) and one old (OL2) could actually be distinguished in the beech forest soil. The n-alkane signature of the parent plants was preserved in the top litter. Immediately underneath, in the OF layer(s) the original il-alkane signatures were progressively but rapidly replaced by a common signature composed of n-C-27 and n-C-25 With larger proportions of the former than of the latter. These two hydrocarbons were most probably produced in situ by fungi. These results appear to illustrate the action of soil microorganisms which metabolize the inherited n-alkanes and produce new compounds of the same family. Unlike the alkanes and the low molecular weight fatty acids less than or equal to C-20 (which increase greatly in the OL2 layer under beech as a result of intense microbial activity), the heavy fatty acids (>C-20) show no significant change in the organic horizon

Photoluminescence characterization of KH2PO4 crystal: Application to three-dimensional growth-sector identification

International audienc

Photoluminescence and photothermal deflection measurements in KDP crystals for high power applications

International audienc