Lipid and Nucleic Acid Chemistries: Combining the Best of Both Worlds to Construct Advanced Biomaterials

Hybrid synthetic amphiphilic biomolecules are emerging as promising supramolecular materials for biomedical and technological applications. Herein, recent progress in the field of nucleic acid based lipids is highlighted with an emphasis on their molecular design, synthesis, supramolecular properties, physicochemical behaviors, and applications in the field of health science and technology. In the first section, the design and the study of nucleolipids are in focus and then the glyconucleolipid family is discussed. In the last section, recent contributions of responsive materials involving nucleolipids and their use as smart drug delivery systems are discussed. The supramolecular materials generated by nucleic acid based lipids open new challenges for biomedical applications, including the fields of medicinal chemistry, biosensors, biomaterials for tissue engineering, drug delivery, and the decontamination of nanoparticles.     

Damage Evaluation in Woven Glass Reinforced Polyamide 6.6/6 Composites Using Ultrasound Phase-Shift Analysis and X-ray Tomography

The paper proposes a new experimental methodology, based on ultrasonic measurements, that aims at evaluating the anisotropic damage in woven semi-crystalline polymer composites through new damage indicators. Due to their microstructure, woven composite materials are characterized by an anisotropic evolution of damage induced by different damage mechanisms occurring at the micro or mesoscopic scales. In this work, these damage modes in polyamide 6.6/6-woven glass fiber reinforced composites have been investigated qualitatively and quantitatively by X-ray micro-computed tomography (mCT) analysis on composite samples cut according to two orientations with respect to the mold flow direction. Composite samples are initially damaged at different levels during preliminary interrupted tensile tests. Ultrasonic investigations using C-scan imaging have been carried out without yielding significant results. Consequently, an ultrasonic method for stiffness constants estimation based on the bulk and guided wave velocity measurements is applied. Two damage indicators are then proposed. The first consists in calculating the Frobenius norm of the obtained stiffness matrix. The second is computed using the phase shift between two ultrasonic signals respectively measured on the tested samples and an undamaged reference sample. Both X-ray mCT and ultrasonic investigations show a higher damage evolution with respect to the applied stress for the samples oriented at \(45^{\circ }\) from the warp direction compared to the samples in the \(0^{\circ }\) configuration. The evolution of the second ultrasonic damage indicator exhibits a good correlation with the void volume fraction evolution estimated by mCT as well as with the damage calculated using the measured elastic modulus reduction. The merit of this research is of importance for the automotive industry.     

Effective viscoelastic behavior of short fibers composites using virtual DMA experiments

Mechanics of Time-Dependent Materials - May it be for environmental or economic reasons, mass reduction has become one of the main goals in mechanics. The short fiber thermoplastics composite is an...     

Decentralized estimation of forest fire spread using reactive and cognitive mobile sensors

This paper presents a study of the ability to build an observer for a complex system using a decentralized multi-agent system for the coordination of mobile sensors. The environment is modeled using a CA model representing forest fire spread. The initial distribution for the different species in the vegetation is generated using a Perlin algorithm. Implementation is realized on GPGPU. A coherence measure for the observation error is defined. The observation itself is realized with mobile sensors and a decentralized coordination of the trajectories. We analyze the balance between individual and collective behaviours of agents which is required to achieve the best performance with respect to the chosen coherence measure. Two kinds of agent’ behaviour are studied: reactive and cognitive.     

Selfishness in secure internet of things networks: 6TiSCH case study

Wireless Networks - Performance and communication security in the Internet of Things (IoT) area draw a major concern for both academic and industrial communities. Indeed, an emerging number of IoT...     

Parallel Light Speed Labeling: an efficient connected component algorithm for labeling and analysis on multi-core processors

In the last decade, many papers have been published to present sequential connected component labeling (CCL) algorithms. As modern processors are multi-core and tend to many cores, designing a CCL algorithm should address parallelism and multithreading. After a review of sequential CCL algorithms and a study of their variations, this paper presents the parallel version of the Light Speed Labeling for connected component analysis (CCA) and compares it to our parallelized implementations of State-of-the-Art sequential algorithms. We provide some benchmarks that help to figure out the intrinsic differences between these parallel algorithms. We show that thanks to its run-based processing, the LSL is intrinsically more efficient and faster than all pixel-based algorithms. We show also, that all the pixel-based are memory-bound on multi-socket machines and so are inefficient and do not scale, whereas LSL, thanks to its RLE compression can scale on such high-end machines. On a 4 × 15-core machine, and for 8192 × 8192 images, LSL outperforms its best competitor by a factor ×10.8 and achieves a throughput of 42.4 gigapixel labeled per second.     

Elastomer monolayers adsorbed on mica surfaces by nitroxide-mediated polymerisation

We reported the first synthesis of Poly(n-butyl acrylate) by in situ nitroxide-mediated polymerisation from the surface of mica while preserving its lamellar structure. To obtain this polymer adsorbed to mica surface, a free radical initiator 2,2′-azobis(isobutyramidine hydrochloride) (AIBA) was attached by ion exchange to the surface of mica, and the resulting was used as a initiator to polymerise butyl acrylate. The kinetic studies show that the initiator adsorbed to mica surface successfully initiated the radical polymerisation of butyl acrylate. Adsorbed polymer was indeed obtained, in different amounts depending on reaction time, the XRD patterns of resulting products indicate that the polymer chains did not intercalate the aluminosilicate layers, as expected.     

Poly(arylene ether sulfones) and poly(arylene ether ketones) derived from dibenzofuran

Summary New polyarylene ether ketones and polyarylene ether sulfones were prepared by polycondensation of various bisphenols with two new dihalide monomers including dibenzofuran structure, respectively 3,6 bis (4-fluorophenylcarbonyl) dibenzofuran and 3,6 bis (4-fluorophenylsulfonyl) dibenzofuran. Most of these thermoplastic polyethers are soluble in NMP and in chlorinated soluents. They exhibit Tgs up to 234°C for the polyetherketones and up to 262°C for the polysulfones, so over 50°C higher than the Tgs of classical available polyethers.