Mesure de la perméabilité aux gaz des revêtements de pyrocarbone isotrope

Gas permeability of pyrocarbon (PyC) coatings of Biso fuel particles for high temperature gas cooled reactors has been evaluated by various methods both physical and physical chemistry measurements. It was established that the gaseous chlorine leach method associated with ceramographic examinations of ThO₂ kernels is more suitable than PyC texture tests for routine control; the flow measurement of a labelled gas (¹⁴CO₂) accross the PyC coating is a technique available only in the laboratory. Moreover, it seems that the pore volume-size distribution is related to the permeability which would be rather attributed to the micropores.     

X-ray tomographic observations of microcracking patterns in fibre-reinforced mortar during tension stiffening tests

For the last decades, new reparation or fabrication processes have been studied to replace traditional rebar by roving of different mineral or organic fibres to avoid corrosion issues. Such materials refer to the family of cementitious composite. Their tensile strength would directly depend on the proportion of reinforcement and strongly on the interfacial mechanical properties between fibres and cementitious matrix. From now, evaluation of interfacial properties was mostly limited to the use of force–displacement curves obtained from mechanical experiments. This work presents a new methodology using micromechanical tension stiffening tests combined with X-ray computed tomography (XRCT) observations, performed at the Anatomix beamline at Synchrotron SOLEIL, and specific image processing procedures. Multi-XRCT acquisitions with suitable scanning strategy are used to image the whole fibre-matrix interface along centimetric samples at four to five different levels of loading magnitude. Intensive image processing is then performed on tomographic images including digital volume correlation (DVC), image subtraction and Hessian-based filtering. This experiment allows to study damage mechanisms at small scale. The proposed methodology shows great potential to provide both qualitative and quantitative elements on interfacial mechanical behaviour such as crack growth and crack orientation. The interface between mortar and sufficiently small multi-fibre yarn used in this paper is shown to behave in certain condition as traditional rebar interface producing conical cracks in the surrounding matrix rather than debonding in mode 2, permitting a much higher energy dissipation during debonding. According to this study, conical cracks repartition and geometry are mostly influenced by the cementitious matrix. The spacing between cracks goes from 50 to 100 μm, and the angle between crack normal vector and yarn orientation goes from 35° to 50°.     

Molecularly Hybridized Conduction in DPP-Based Donor–Acceptor Copolymers toward High-Performance Iono-Electronics

Iono-electronics, that is, transducing devices able to translate ionic injection into electrical output, continue to demand a variety of mixed ionic–electronic conductors (MIECs). Though polar sidechains are widely used in designing novel polymer MIECs, it remains unclear to chemists how much balance is needed between the two antagonistic modes of transport (ion permeability and electronic charge transport) to yield high-performance materials. Here, the impact of molecularly hybridizing ion permeability and charge mobility in semiconducting polymers on their performance in electrochemical and synaptic transistors is investigated. A series of diketopyrrolopyrrole (DPP)-based copolymers are employed to demonstrate the multifunctionality attained by controlling the density of polar sidechains along the backbone. Notably, efficient electrochemical signal transduction and reliable synaptic plasticity are demonstrated via controlled ion insertion and retention. The newly designed DPP-based copolymers further demonstrate unprecedented thermal tolerance among organic mixed ionic–electronic conductors, a key property in the manufacturing of organic electronics.     

Organoleptic characterization and PAH content of salmon (Salmo salar) fillets smoked according to four industrial smoking techniques

Four industrial processes for smoking food were studied through their effects on the organoleptic properties of smoked salmon and on the occurrence of 20 polycyclic aromatic hydrocarbons (PAHs) known as being contaminants of smoking processes. The contamination by PAHs of the food might be measured by their corresponding toxic equivalent quantity (TEQ) expressed in µg kg^?1. The results show a significant correlation between the smoking process parameters, the odour of the smoked fish and the presence of PAHs. Smouldering, thermostated plates and friction smoking processes allow smoked fish with very close odorant characteristics to be obtained. However, differences of pyrolysis temperature (between 380 and 500 °C) causes significant differences of PAHs concentration even if the contents are under the legal threshold concerning benzo(a)pyrene (5 µg kg^?1). Smoked fish obtained by liquid smoke vaporisation presented the lowest level of PAHs but benzo(a)pyrene concentration is nevertheless important. The odours brought by the liquid smoke process are more ‘cold smoke’ and ‘vegetal/green’ than the other techniques, which are smokier and fishier. Copyright © 2007 Society of Chemical Industry     

Turbo Product Code Decoder Without Interleaving Resource: From Parallelism Exploration to High Efficiency Architecture

This article proposes to explore parallelism in Turbo-Product Code (TPC) decoding through a parallelism level classification and characterization. From this design space exploration, an innovative TPC decoder architecture without any interleaving resource is presented. This architecture includes a fully-parallel SISO decoder capable of processing n symbols in one clock period. Syntheses results show the better efficiency of such an architecture compared with existing solutions. Considering a six-iteration turbo decoder of a BCH(32,26)² product code, synthesized in 90 nm CMOS technology, 10 Gb/s can be achieved with an area of 600 Kgates. Moreover, a second architecture enhancing parallelism rate is described. The throughput is 50 Gb/s while an area estimation gives 2.2 Mgates. Finally, comparisons with existing TPC decoders and existing LDPC decoders are performed. They validate the potential of proposed TPC decoder for Gb/s optical fiber transmission systems.     

A Bayesian hierarchical correlation model for fMRI cluster analysis

Data-driven cluster analysis is potentially suitable to search for, and discriminate between, distinct response signals in blood oxygenation level-dependent functional magnetic resonance imaging (BOLD fMRI), which appear during cerebrovascular disease. In contrast to model-driven methods, which test for a particular BOLD signal whose shape must be given beforehand, data-driven methods generate a set of BOLD signals directly from the fMRI data by clustering voxels into groups with correlated time signals. Here, we address the problem of selecting only the clusters that represent genuine responses to the experimental stimulus by modeling the correlation structure of the clustered data using a Bayesian hierarchical model. The model is empirically justified by demonstrating the hierarchical organization of the voxel correlations after cluster analysis. BOLD signal discrimination is demonstrated using: 1) simulations that contain multiple pathological BOLD response signals; and 2) fMRI data acquired during an event-related motor task. These demonstrations are compared with results from a model-driven method based on the general linear model. Our simulations show that the data-driven method can discriminate between the BOLD response signals, while the model-driven method only finds one signal. For fMRI, the data-driven method distinguishes between the BOLD signals appearing in the sensorimotor cortex and those in basal ganglia and putamen, while the model-driven method combines these signals into one activation map. We conclude that the proposed data-driven method provides an objective framework to identify and discriminate between distinct BOLD response signals.     

High-throughput droplet digital PCR system for absolute quantitation of DNA copy number

Digital PCR enables the absolute quantitation of nucleic acids in a sample. The lack of scalable and practical technologies for digital PCR implementation has hampered the widespread adoption of this inherently powerful technique. Here we describe a high-throughput droplet digital PCR (ddPCR) system that enables processing of ~2 million PCR reactions using conventional TaqMan assays with a 96-well plate workflow. Three applications demonstrate that the massive partitioning afforded by our ddPCR system provides orders of magnitude more precision and sensitivity than real-time PCR. First, we show the accurate measurement of germline copy number variation. Second, for rare alleles, we show sensitive detection of mutant DNA in a 100,000-fold excess of wildtype background. Third, we demonstrate absolute quantitation of circulating fetal and maternal DNA from cell-free plasma. We anticipate this ddPCR system will allow researchers to explore complex genetic landscapes, discover and validate new disease associations, and define a new era of molecular diagnostics.     

Improved nursing home end-stage renal disease patient participation in physical therapy with onsite,more frequent dialysis

Introduction

For end-stage renal disease (ESRD) patients residing in skilled nursing facilities (SNFs), the logistics and physical exhaustion of life-saving hemodialysis therapy often conflict with rehabilitation goals. Integration of dialysis care with rehabilitation programs in a scalable and cost-efficient manner has been a significant challenge. SNF-resident ESRD patients receiving onsite, more frequent hemodialysis (MFD) have reported rapid post-dialysis recovery. We examined whether such patients have improved Physical Therapy (PT) participation.

Methods

We conducted a retrospective electronic medical records review of SNF-resident PT participation rates within a multistate provider of SNF rehabilitation care from January 1, 2022 to June 1, 2022. We compared three groups: ESRD patients receiving onsite MFD (Onsite-MFD), ESRD patients receiving offsite, conventional 3×/week dialysis (Offsite-Conventional-HD), and the general non-ESRD SNF rehabilitation population (Non-ESRD). We evaluated physical therapy participation rates based on a predefined metric of missed or shortened (<15 min) therapy days. Baseline demographics and functional status were assessed.

Findings

Ninety-two Onsite-MFD had 2084 PT sessions scheduled, 12,916 Non-ESRD had 225,496 PT sessions scheduled, and 562 Offsite-Conventional-HD had 9082 PT sessions scheduled. In mixed model logistic regression, Onsite-MFD achieved higher PT participation rates than Offsite-Conventional-HD (odds ratio: 1.8, CI: 1.1–3.0; p < 0.03), and Onsite-MFD achieved equivalent PT participation rates to Non-ESRD (odds ratio: 1.2, CI: 0.3–1.9; p < 0.46). Baseline mean ± SD Charlson Comorbidity score was significantly higher in Onsite-MFD (4.9 ± 2.0) and Offsite-Conventional-HD (4.9 ± 1.8) versus Non-ESRD (2.6 ± 2.0; p < 0.001). Baseline mean self-care and mobility scores were significantly lower in Onsite-MFD versus Non-ESRD or Offsite-Conventional-HD.

Discussion

SNF-resident ESRD patients receiving MFD colocated with rehabilitation had higher PT participation rates than those conventionally dialyzed offsite and equivalent PT participation rates to the non-ESRD SNF-rehabilitation general population, despite being sicker, less independent, and less mobile. We report a scalable program integrating dialysis and rehabilitation care as a potential solution for ESRD patients recovering from acute hospitalization.