Morphology and thermo-mechanical properties of new hybrid coatings based on polyester/melamine resin and pyrogenic silica

Polyester/melamine (PM)-based formulations used in coil-coating applications were modified with pyrogenic silicas of different types. The influence of the chemical modification of the silica surface on various properties was investigated. The viscosity of filled PM formulations was measured. Transmission electron microscopy and dynamic mechanical measurements were used to characterize nanocomposite films. Roughness and gloss measurements were done on nanocomposite coatings. The results show that the viscosity and morphology observed are directly linked to the balance and nature of the interactions developed between the silica surface and the organic medium. Both hydrophilic and hydrophobic silica lead to too high viscosity of the filled formulation, to different silica dispersion and, as a consequence, to low gloss coatings. However with an adequate organo-modification of the silica, formulations compatible with the process and having a high gloss can be obtained. Additionally, the surface modification of silica has no obvious influence on the dynamic mechanical properties.     

Submicrometric gratings fabrication from photosensitive organo-silica-hafnia thin films elaborated by sol-gel processing

The aim of this study is the elaboration of a high index sol-gel material in order to prepare submicrometric grating. The gratings were obtained after few seconds of UV exposure in one step using an organically modified silica-hafnia matrix. The chemical composition of thin films after UV and annealing treatments were studied using Fourier Transform Infrared Spectroscopy and X-Ray Photoelectron Spectroscopy. The study of optical properties revealed that the annealed films are transparent from 200 to 1000 nm and have a refractive index from 1.550 to 1.701 depending on the hafnium concentration.     

Influence of maturation and cooking treatments on the nutritional value of bovine meats: Water losses and vitamin B12

The aim of the study was to determine the influence of maturation and of cooking processes on water losses and on the vitamin B12 content of meat. Three types of muscle (Longissimus lumborum, Longissimus thoracis and Triceps brachii) were sampled from a total of 16 animals, representative of animals raised for meat production in France. Three durations of maturation were compared: 1, 3 and 14 days. Different cooking processes were applied: Longissimus lumborum was deep-fat fried or roasted, Longissimus thoracis was pan fried or grilled and Triceps brachii was braised. The cooking yield averaged 55-56% for Triceps brachii, 73-77% for Longissimus lumborum and 85-87% for Longissimus thoracis. Vitamin B12 concentration in raw meat was significantly higher in Triceps brachii than in Longissimus lumborum and Longissimus thoracis (20.86, 11.53 and 9.21ng/g wet tissue, in the same respective order). When expressed on a wet weight basis, all concentrations were significantly increased by cooking. When expressed on a lipid-free dry basis, significant losses in vitamin B12 were measured only in the braised Triceps brachii (-25%) and in the deep-fat fried Longissimus lumborum (-5.5%) as a result of long duration and high temperature of cooking, respectively. Maturation did not affect the vitamin B12 content of meat, whether raw or cooked.     

Impact of 20∶4n−6 supplementation on the fatty acid composition and hemocyte parameters of the pacific oyster crassostrea gigas

Arachidonic acid (20∶4n−6, ArA) and its eicosanoid metabolites have been demonstrated to be implicated in immune functions of vertebrates, fish, and insects. Thus, the aim of this study was to assess the impact of ArA supplementation on the FA composition and hemocyte parameters of oysters Crassostrea gigas. Oyster dietary conditioning consisted of direct addition of ArA solutions at a dose of 0, 0.25, or 0.41 μg ArA per mL of seawater into tanks in the presence or absence of T-Iso algae. Results showed significant incorporation of ArA into gill polar lipids when administered with algae (up to 19.7%) or without algae (up to 12.1%). ArA supplementation led to an increase in hemocyte numbers, phagocytosis, and production of reactive oxygen species by hemocytes from ArA-supplemented oysters. Moreover, the inhibitory effect of Vibrio aestuarianus extracellular products on the adhesive proprieties of hemocytes was lessened in oysters fed ArA-supplemented T-Iso. All changes in oyster hemocyte parameters reported in the present study suggest that ArA and/or eicosanoid metabolites affect oyster hemocyte functions.     

Functionally Graded,Bone‐ and Tendon‐Like Polyurethane for Rotator Cuff Repair

Critical considerations in engineering biomaterials for rotator cuff repair include bone‐tendon‐like mechanical properties to support physiological loading and biophysicochemical attributes that stabilize the repair site over the long‐term. In this study, UV‐crosslinkable polyurethane based on quadrol (Q), hexamethylene diisocyante (H), and methacrylic anhydride (M; QHM polymers), which are free of solvent, catalyst, and photoinitiator, is developed. Mechanical characterization studies demonstrate that QHM polymers possesses phototunable bone‐ and tendon‐like tensile and compressive properties (12–74 MPa tensile strength, 0.6–2.7 GPa tensile modulus, 58–121 MPa compressive strength, and 1.5–3.0 GPa compressive modulus), including the capability to withstand 10 000 cycles of physiological tensile loading and reduce stress concentrations via stiffness gradients. Biophysicochemical studies demonstrate that QHM polymers have clinically favorable attributes vital to rotator cuff repair stability, including slow degradation profiles (5–30% mass loss after 8 weeks) with little‐to‐no cytotoxicity in vitro, exceptional suture retention ex vivo (2.79–3.56‐fold less suture migration relative to a clinically available graft), and competent tensile properties (similar ultimate load but higher normalized tensile stiffness relative to a clinically available graft) as well as good biocompatibility for augmenting rat supraspinatus tendon repair in vivo. This work demonstrates functionally graded, bone‐tendon‐like biomaterials for interfacial tissue engineering.     

EUA and sCER phase II price drivers: Unveiling the reasons for the existence of the EUA–sCER spread

This article studies the price relationships between EU emissions allowances (EUAs) – valid under the EU Emissions Trading Scheme (EU ETS) – and secondary Certified Emissions Reductions (sCERs)—established from primary CERs generated through the Kyoto Protocol's Clean Development Mechanism (CDM). Given the price differences between EUAs and sCERs, financial and industrial operators may benefit from arbitrage strategies by buying sCERs and selling EUAs (i.e. selling the EUA–sCER spread) to cover their compliance position as industrial operators are allowed to use sCERs towards compliance with their emissions cap within the European system up to 13.4%. Our central results show that the spread is mainly driven by EUA prices and market microstructure variables and less importantly, as we would expect, by emissions-related fundamental drivers. This might be justified by the fact that the EU ETS remains the greatest source of CER demand to date.     

Targeted heat treatment of additively manufactured Ti-6Al-4V for controlled formation of Bi-lamellar microstructures

Laser powder bed fusion (L-PBF) was utilized to produce specimens in Ti-6Al-4V,which were subjected to a bi-lamellar heat treatment,which produces microstructures consisting of primary α-lamellae and a fine secondary α-phase inside the inter-lamellar β-regions.The bi-lamellar microstructure was obtained as (i)a direct bi-lamellar heat treatment from the asbuilt condition or (ii) a bi-lamellar heat treatment preceded by a β-homogenization.For the bi-lamellar treatment with β-homogenization,cooling rates in the range 1-500 K/min were applied after homogenization in β-region followed by inter-critical annealing in the α + β region at various temperatures in the range 850-950 ℃.The microstructures were characterized using various microscopical techniques.Mechanical testing with Vickers hardness indentation and tensile testing was performed.The bi-lamellar microstructure was harder when compared to a soft fully lamellar microstructure,because of the presence of fine α-platelets inside the β-lamellae.Final low temperature ageing provided an additional hardness increase by precipitation hardening of the primary α-regions.The age hardened bi-lamellar microstructure shows a similar hardness as the very fine,as-built martensitic microstructure.The bi-lamellar microstructure has more favorable mechanical properties than the as-built condition,which has high strength,but poor ductility.After the bi-lamellar heat treatment,the elongation was improved by more than 250 ％.Due to the very high strength of the as-built condition,loss of tensile strength is unavoidable,resulting in a reduction of tensile strength of～18 ％.     

From Molecular Machines to Stimuli-Responsive Materials

Artificial molecular machines are able to produce and exploit precise nanoscale actuations in response to chemical or physical triggers. Recent scientific efforts have been devoted to the integration, orientation, and interfacing of large assemblies of molecular machines in order to harness their collective actuations at larger length scale and up to the generation of macroscopic motions. Making use of such “hierarchical mechanics” represents a fundamentally new approach for the conception of stimuli-responsive materials. Furthermore, because some molecular machines can function as molecular motors—which are capable of cycling a unidirectional motion out of thermodynamic equilibrium and progressively increasing the work delivered to their environment—one can expect unique opportunities to design new kinds of mechanically active materials and devices capable of autonomous behavior when supplied by an external source of energy. Recently reported achievements are summarized, including the integration of molecular machines at surfaces and interfaces, in 3D self-assembled materials, as well as in liquid crystals and polymer materials. Their detailed functioning principles as well as their functional properties are discussed along with their potential applications in various domains such as sensing, drug delivery, electronics, optics, plasmonics, and mechanics.     

ONTOLOGY-BASED USER MODELING AND E-PORTFOLIO GRID LEARNING SERVICES

Several challenges need to be met by a new generation of learning services. On one hand, they need to fit into a ubiquitous and serendipitous learning vision, to adapt to different types of users with different backgrounds and needs. On the other hand, they need to integrate modern pedagogical approaches of learning. These services will probably rely on the cooperation of different distributed, autonomous, goal-oriented entities, and they can be Grid- or Web-Oriented. In this paper, we show how core technologies can contribute to the development of a next generation of learning services. In particular, we focus our attention on personalized services delivery for learning by employing an ontological perspective and user modeling techniques. This paper presents some preliminary results obtained within Elegi FP6 project.