Kinetic model of solute aqueous extraction from Fennel (Foeniculum vulgare) treated by pulsed electric field, electrical discharges and ultrasonic irradiations

This work investigates the aqueous extraction from Fennel (Foeniculum vulgare) assisted by pulsed electric field (PEF), electrical discharges (ED) and ultrasound irradiations (UI). It aims the improvement of the solutes yield and the extraction kinetics at room temperature.Fennel gratings of size (1.5 × 0.75 × 30-50 mm³; width × height × length), were treated by PEF (intensity: 50-1200 V/cm and number of pulses: 50-1000), ED (voltage: 40 kV and number of discharges: 10-60) and ultrasound (intensity: 400 W/cm² and treatment duration: 10-350 min). The liquid-to-solid (weight/weight) ratio equal to 2. All tests were carried out at room temperature (20 °C), under stirring at 250 rpm. The extraction kinetics was modelled using a simplified two-exponential kinetic model, which corresponds to mass transfer in two stages (rapid washing and slow diffusion).The optimal parameters of PEF, ED and UI, giving the maximal juice yield, were determined and the effect of these three treatments on the mass transfer rate was studied.     

Striped nanowires and nanorods from mixed SAMS

We investigate the use of mixed self-assembled monolayers (SAMs) for creating nanoscale striped patterns on nanowires and nanorods. Our simulations predict that SAMs comprised of an equal composition of length-mismatched, thermodynamically incompatible surfactants adsorbed on nanowire surfaces self-organize into equilibrium stripes of alternating composition always perpendicular, rather than parallel, to the nanowire axis. We support the simulation results with preliminary experimental investigations of gold nanorods coated with binary mixtures of ligand molecules, which show stripes roughly perpendicular to the rod axis in all cases.     

Bacterial Catabolism of Biphenyls: Synthesis and Evaluation of Analogues

A series of alkylated 2,3‐dihydroxybiphenyls has been prepared on the gram scale by using an effective Directed ortho Metalation–Suzuki–Miyaura cross‐coupling strategy. These compounds have been used to investigate the substrate specificity of the meta‐cleavage dioxygenase BphC, a key enzyme in the microbial catabolism of biphenyl. Isolation and characterization of the meta‐cleavage products will allow further study of related processes, including the catabolism of lignin‐derived biphenyls.     

NO emission of oxygen-enriched CH4/O2/N2 premixed flames under electric field

This work investigates the electric field effect on nitrogen oxide (NO) pollutant formation and emission composition of premixed flames in order to provide better insight on the mechanism of controlling the combustion process by electro-physical means. The present study aims to investigate experimentally the effect of radial DC electric field on premixed laminar methane flame. The electric field effect on flame shape, emission composition and NO emission index of flame is investigated experimentally under the action of direct-current electric field under varying equivalence ratio and level of oxygen enrichment. The results show that ionic wind effects cause the distortion in flame shape. The ionic wind effects diminish with increasing flow rate and level of oxygen enrichment. Minimal effects on NO are measured for flames under the influence of electric field and vanished as the level of oxygen enrichment is increased. This was well supported by the temperature profile measurement in the post flame gas showing no field-induced modification also. It seemed that the action of an electric field on a flame with a geometry that remains practically undeformed produces very minimal effect on pollutant emission.     

Large Charged Drop Levitation Against Gravity

A hybrid electrostatic-acoustic levitator that can levitate and manipulate a large liquid drop in one gravity is presented. To the authors' knowledge, this is the first time such large drops (up to 4 mm in diameter in the case of water) have been levitated against 1-gravity. This makes possible, for the first time, many new experiments both in space and in ground-based laboratories, such as 1) supercooling and superheating, 2) containerless crystal growth from various salt solutions or melts, 3) drop dynamics of oscillating or rotating liquid drops, 4) drop evaporation and Rayleigh bursting, and 5) containerless material processing in space. The digital control system, liquid drop launch process, principles of electrode design, and design of a multipurpose room temperature levitation chamber are described. Preliminary results that demonstrate drop oscillation and rotation, and crystal growth from supersaturated salt solutions are presented.     

Genes Involved in the Endoplasmic Reticulum N-Glycosylation Pathway of the Red Microalga Porphyridium sp.: A Bioinformatic Study

N-glycosylation is one of the most important post-translational modifications that influence protein polymorphism, including protein structures and their functions. Although this important biological process has been extensively studied in mammals, only limited knowledge exists regarding glycosylation in algae. The current research is focused on the red microalga Porphyridium sp., which is a potentially valuable source for various applications, such as skin therapy, food, and pharmaceuticals. The enzymes involved in the biosynthesis and processing of N-glycans remain undefined in this species, and the mechanism(s) of their genetic regulation is completely unknown. In this study, we describe our pioneering attempt to understand the endoplasmic reticulum N-Glycosylation pathway in Porphyridium sp., using a bioinformatic approach. Homology searches, based on sequence similarities with genes encoding proteins involved in the ER N-glycosylation pathway (including their conserved parts) were conducted using the TBLASTN function on the algae DNA scaffold contigs database. This approach led to the identification of 24 encoded-genes implicated with the ER N-glycosylation pathway in Porphyridium sp. Homologs were found for almost all known N-glycosylation protein sequences in the ER pathway of Porphyridium sp.; thus, suggesting that the ER-pathway is conserved; as it is in other organisms (animals, plants, yeasts, etc.).     

Synthesis and gas permeation parameters of metathesis polytricyclononenes with pendant Me3E‐groups (E = C,Si, Ge)

Metathesis polytricyclononenes were synthesized via ROMP polymerization in the presence of the 1‐st generation Grubbs catalyst and their gas‐transport properties were studied for the first time. The aim of this work was to evaluate the influence of Me₃E‐groups (E = C, Si, Ge) on gas permeation parameters of ROMP materials. New metathesis poly(3‐tert‐butyltricyclononene‐7) and poly(3‐trimethylgermyltricyclononene‐7) were obtained with high yields (up to 95%) and high‐molecular weights (M_w～3–7×10⁵ g mol^?1). The glass transition temperatures of the ROMP polytricyclononenes with Me₃E‐groups decreased when E was changed from C to Si and then to Ge. It was shown that the polytricyclononene containing Me₃Si‐groups has the highest gas permeability while the polytricyclononene containing Me₃C‐substituents has the lowest gas permeability. In addition, the gas permeation parameters were estimated for ROMP Me₃Si‐ and Me₃Ge‐substituted polytricyclonona‐3,7‐dienes. So the influence of the second double bond in the monomer units on the permeability of the polymers obtained was studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41395.     

Selective decomposition of isopropanol using as prepared and oxidized graphite nanofibers

Three types of as prepared and treated graphite nanofibers (GNFs) were used as catalysts in the decomposition of isopropanol to propene and acetone in the presence of oxygen to evaluate the surface chemistry of the fibers. As prepared herringbone fibers were found to produce higher selectivity for propene compared to the as prepared platelet and ribbon fibers at all temperatures explored. Herringbone fibers that had undergone oxidative treatment with nitric acid, phosphoric acid, ruthenium tetroxide or potassium permanganate were also evaluated at a 290 °C. Effects of oxidation treatments on fiber structure were evaluated using a host of analytical techniques including BET, SEM/EDS, TGA, XPS, and fluorescence labeling of surface species. Selectivity for acetone dehydrogenation product or propene dehydration product could be achieved by the appropriate surface treatment. Nitric acid was the mildest treatment and the treated fibers showed minimal changes. (Potassium permanganate was a harsh treatment that almost completely degraded fiber structure, creating amorphous carbon.) Phosphoric acid treated fibers were found to produce very high conversions and almost pure selectivity for propene. Ruthenium tetroxide did not appear to have a large affect on fiber morphology; however, selectivity for acetone was much higher when GNFs were treated with ruthenium tetroxide.     

Synthesis of single-walled carbon nanotubes using hemoglobin-based iron catalyst

Hemoglobin (Hb) was used as a catalyst for the growth of single-walled carbon nanotubes (SWCNTs). Hb was deposited onto a hydrophilic treated substrate by spin coating method. After oxidation at 800 °C, protein chains were decomposed and iron oxide nanoparticles remained with an average diameter of 2.29 nm. High quality SWCNTs were synthesized with an average diameter of 1.22 nm. The protein chains prevent iron atoms aggregation and so the size of the nanoparticles is smaller than that from ferritin-like proteins.     

The concept of a near-field Raman probe

This article considers the possibility to use tips, which are functionalised by Raman active molecules, as new Raman probes for near-field optics in such a way that the Raman spectrum can be recorded of such a tip. If the Raman spectrum of the probe molecules is sensitive to their immediate environment, the probe can be used to map a surface by its local influence on the Raman spectrum of the probe. This new concept may be very promising for the investigation of specific interactions at the nanoscale by an optical response. Examples of the sensitivity of such a probe to the local environment are presented as a basis for further development of such a probe.