Polyethylene/carbon nanotube nano hybrid shish-kebab obtained by solvent evaporation and thin-film crystallization

Crystallization of polymers on carbon nanotubes (CNTs) has resulted in a novel nano hybrid shish kebab (NHSK) structure, within which CNTs serve as the nucleation sites (shish) and polymer lamellar crystals form the kebabs. Previously reported NHSK structures were obtained by solution crystallization, bulk crystallization and physical vapor deposition methods. Herein we report a simple, rapid, yet effective approach to produce NHSK materials using solvent evaporation and thin film crystallization. Polyethylene (PE) was used as the model polymer. PE solution was drop cast on CNT-coated carbon films, and upon solvent evaporation, PE crystallized onto/near CNTs, following the template of the latter and NHSK structure was then formed. The final morphology was found to result from the competition between heterogeneous nucleation and homogeneous nucleation of PE. The formation of NHSK also strongly depends on the structure of CNTs as well as the molecular weight of PE. This work shows a facile method to form NHSK and to study CNT-induced crystallization under nonequilibrium conditions.     

From driving cycle analysis to understanding battery performance in real-life electric hybrid vehicle operation

This paper proposes a methodology and approach to understand battery performance and life through driving cycle and duty cycle analyses from electric and hybrid vehicle (EHV) operation in real-world situations. Conducting driving cycle analysis with trip data collected from EHV operation in real life is very difficult and challenging. In fact, no comprehensive approach has been accepted to date, except those using standard driving cycles on a dynamometer or a track. Similarly, analyzing duty cycle performance of a battery under real-life operation faces the same challenge. A successful driving cycle analysis, however, can significantly enhance our understanding of EHV performance in real-life driving. Likewise, we also expect similar results through duty cycle analysis for batteries. Since 1995, we have been developing tools to analyze EHV and power source performance. In particular, we were able to collect data from a fleet of 15 Hyundai Santa Fe electric sports utility vehicles (e-SUVs) operated on Oahu, Hawaii; from July 2001 to June 2003 to allow driving and duty cycle analyses in order to understand battery pack performance from a variety of EHV operating conditions. We thus developed a comprehensive approach that comprises fuzzy logic pattern recognition (FL-PR) techniques to perform driving and duty cycle analyses. This approach has been successfully applied to EHV performance analysis via the creation of a compositional driving profile called “driving cycle profile” (DrCP) for each trip. The same approach was used to analyze battery performance via the construction of “duty cycle profile” (DuCP) to express battery usage under various operating conditions. The combination of the two analyses enables us to understand both the usage profile of EHV and battery performance in synergetic details and in a systematic manner using a pattern recognition technique.     

Origin of an intermediate peak in DMTA analysis of multilayer ABS/PC samples

Three layers film shaped by thermocompression of acrylonitrile butadiene styrene copolymer and polycarbonate have been analyzed in dynamic mechanical thermal analysis in tensile mode. They present two peaks as the film is loaded perpendicularly to the layers and three peaks as the film is loaded in parallel to the layers. Numerical computations confirm that the origin of this peak is not related to a mechanical issue such as the transmission of the imposed deformation from one layer to the other. Using this method, it is demonstrated that this third peak can only be obtained assuming a material transition with its own behavior between layers. Tan δ measurements provide a simple and useful experimental tool to understand more about the interfacial zone in polymer blends.     

Dissolved and particulate metals (Fe, Zn, Cu, Cd, Pb) in two habitats from an active hydrothermal field on the EPR at 13 degrees N

The distribution of Fe, Cu, Zn, Pb, Cd between the dissolved (<2 microm) and the particulate (>2 microm) fractions was measured after in-situ filtration in two hydrothermal habitats. The total metal concentration ranges exhibit a clear enrichment compared with the seawater concentration, accounting for the hydrothermal input for all the metals considered. Iron is the predominant metal (5-50 microM) followed by Zn and Cu. Cd and Pb are present at the nM level. At the scale studied, the behavior of temperature, pH and dissolved iron is semi-conservative whereas the other dissolved and particulate metals are characterized by non-conservative patterns. The metal enrichment of the >2 microm fraction results from the settlement and accumulation of particulate matter close to the organisms, acting as a secondary metal source. The enrichment observed in the dissolved fraction can be related to the dissolution or oxidation of particles (mainly polymetallic sulfide) or to the presence of small particles and large colloids not retained on the 2 microm frit. SEM observations indicate that the bulk particulate observed is characteristic of crystalline particles settling rapidly from the high temperature smoker (sphalerite, wurtzite and pyrite), amorphous structures and eroded particles formed in the external zone of the chimney. Precipitation of Zn, Cu, Cd and Pb with Fe as wurtzite, sphalerite and pyrite is the main process taking place within the area studied and is semi-quantitative. The distribution of the dominant observed fauna has been related to the gradient resulting from the dilution process, with the alvinellids worms colonizing the hotter and more variable part of the mixing zone, but also to the metallic load of the mixing zone. Dissolved and particulate metal concentrations are therefore necessary abiotic factors to be studied in a multiparametric approach to understand the faunal distribution in hydrothermal ecosystems.     

Influence of surface roughness on the supercooling degree: Case of selected water/ethanol solutions frozen on aluminium surfaces

This paper presents a study on the impact of the roughness of a metallic surface on the magnitude of the supercooling during freezing of an aqueous solution. Aqueous solutions of ethanol (5%, 10% and 15% w/w) were used as model solutions. Five tubes of aluminium (internal diameter 8 mm) were machined to obtain a roughness between 0.63 and 13.3 μm. These tubes were immersed in a refrigerated bath with a programmable temperature scan. Thermocouples located at the inner surface of the tubes and in the solution were used to measure the magnitude of supercooling. Crystallisations were monitored and supercooling released calculated for each experiments. Our experimental results reveal that roughness is the influencing parameter of the supercooling released: larger the roughness, lower the supercooling. Moreover, a power law correlation between the roughness and supercooling was deduced.     

Enhancing the implementation of mathematical formulas for fixed-point and floating-point arithmetics

This article introduces some techniques to estimate and to improve the numerical quality of computations performed using different computer arithmetics. A general methodology is introduced and it is applied to the fixed-point and floating-point formats. We show how to globally measure the quality of the implementation of a formula with respect to some quality indicators. In the case of the floating-point arithmetic, the indicator measures the distance between the computer and exact results in the worst case. In the case of the fixed-point arithmetic, the indicator bounds the number of digits needed to represent all the intermediary results. Next, we show how the operations which make mostly decrease the quality of an indicator can be identified. This information helps the programmer to improve the implementation by underlying the main sources of degradation. Finally, we introduce a fully automatic expression transformation technique to rewrite a formula into a better, mathematically equivalent one. The new formula is more accurate than the original one with respect to the chosen quality indicator.     

Protein Alterations in Cardiac Ischemia/Reperfusion Revealed by Spatial-Omics

Myocardial infarction is the most common cause of death worldwide. An understanding of the alterations in protein pathways is needed in order to develop strategies that minimize myocardial damage. To identify the protein signature of cardiac ischemia/reperfusion (I/R) injury in rats, we combined, for the first time, protein matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) and label-free proteomics on the same tissue section placed on a conductive slide. Wistar rats were subjected to I/R surgery and sacrificed after 24 h. Protein MALDI-MSI data revealed ischemia specific regions, and distinct profiles for the infarct core and border. Firstly, the infarct core, compared to histologically unaffected tissue, showed a significant downregulation of cardiac biomarkers, while an upregulation was seen for coagulation and immune response proteins. Interestingly, within the infarct tissue, alterations in the cytoskeleton reorganization and inflammation were found. This work demonstrates that a single tissue section can be used for protein-based spatial-omics, combining MALDI-MSI and label-free proteomics. Our workflow offers a new methodology to investigate the mechanisms of cardiac I/R injury at the protein level for new strategies to minimize damage after MI.     

The Conversion of UDP-Glc to UDP-Man: In Silico and Biochemical Exploration To Improve the Catalytic Efficiency of CDP-Tyvelose C2-Epimerases

A promiscuous CDP-tyvelose 2-epimerase (TyvE) from Thermodesulfatator atlanticus (TaTyvE) belonging to the nucleotide sugar active short-chain dehydrogenase/reductase superfamily (NS-SDRs) was recently discovered. TaTyvE performs the slow conversion of NDP-glucose (NDP-Glc) to NDP-mannose (NDP-Man). Here, we present the sequence fingerprints that are indicative of the conversion of UDP-Glc to UDP-Man in TyvE-like enzymes based on the heptagonal box motifs. Our data-mining approach led to the identification of 11 additional TyvE-like enzymes for the conversion of UDP-Glc to UDP-Man. We characterized the top two wild-type candidates, which show a 15- and 20-fold improved catalytic efficiency, respectively, on UDP-Glc compared to TaTyvE. In addition, we present a quadruple variant of one of the identified enzymes with a 70-fold improved catalytic efficiency on UDP-Glc compared to TaTyvE. These findings could help the design of new nucleotide production pathways starting from a cheap sugar substrate like glucose or sucrose.     

Fermented Pineapple Juice Consumption Limits Metabolic Disorders Associated to Sugary Drinks on High-Fat Diet-Fed Mice

Scope

Lactic acid fermentation (LAF) modulates the composition of food, leading to changes in safety, sensory, and nutritional properties. The effects of lactic fermented pineapple juice (FJ) supplementation on energetic metabolism of high-fat diet (HFD) fed mice are compared with either water (control), sweetened water (SW), bacteria in SW, and pineapple juice (J) supplementation.

Methods and results

Drink consumption and body weight are measured during the 6 weeks of experiment, whereas glycemia and lipid content are determined at the beginning and at the end of the experiment. Total energy intake is similar between all groups though the volume of juice consumed is lower than that of SWs. Weight gain is higher for mice provided with sugary drinks (5.65 ± 1.32 to 7.74 ± 2.98 g) compared to water (4.68 ± 0.93 g). The FJ is less detrimental to blood carbohydrate regulation than other sugary drinks. Triglyceride (TG) and total cholesterol content are not modified following fermented juice or water consumption, contrarily to other sugary drinks. Whatever the drink, intestinal permeability is preserved. Lactic acid bacterium (LAB) population in feces is not affected by the beverage but species composition is modified.

Conclusion

From a health perspective, FJ is preferable to other sugary drinks to limit metabolic disorders related to HFD.     

Laser-Driven Transient Phase Oscillations in Individual Spin Crossover Particles

An unusual expansion dynamics of individual spin crossover nanoparticles is studied by ultrafast transmission electron microscopy. After exposure to nanosecond laser pulses, the particles exhibit considerable length oscillations during and after their expansion. The vibration period of 50–100 ns is of the same order of magnitude as the time that the particles need for a transition from the low-spin to the high-spin state. The observations are explained in Monte Carlo calculations using a model where elastic and thermal coupling between the molecules within a crystalline spin crossover particle govern the phase transition between the two spin states. The experimentally observed length oscillations are in agreement with the calculations, and it is shown that the system undergoes repeated transitions between the two spin states until relaxation in the high-spin state occurs due to energy dissipation. Spin crossover particles are therefore a unique system where a resonant transition between two phases occurs in a phase transformation of first order.