Composite Anion Exchange Membranes Containing a Long-Side Chain Ionomer and Exfoliated Lamellar Double Hydroxides.

Anion Exchange Membranes (AEMs) are promising materials for electrochemical devices, such as fuel cells and electrolyzers. However, the main drawback of AEMs is their low durability in alkaline operating conditions. A possible solution is the use of composite ionomers containing inorganic fillers stable in a basic environment.

Heavy Metal Detection and Removal by Composite Carbon Quantum Dots/Ionomer Membranes.

The combination of ion exchange membranes with carbon quantum dots (CQDs) is a promising field that could lead to significant advances in water treatment. Composite membranes formed by sulfonated poly(ether ether ketone) (SPEEK) with embedded CQDs were used for the detection and removal of heavy metal ions, such as lead and cadmium, from water. SPEEK is responsible for the capture of heavy metals based on the cation exchange mechanism, while CQDs detect their contamination by exhibiting changes in fluorescence.

Leaf morpho-anatomical adjustments in a Quercus pubescens forest after 10 years of partial rain exclusion in the field.

In the Mediterranean region, a reduction of annual precipitation and a longer and drier summer season are expected with climate change by the end of the century, eventually endangering forest survival. To cope with such rapid changes, trees may modulate their morpho-anatomical and physiological traits. In the present study, we focused on the variation in leaf gas exchange and different leaf morpho-anatomical functional traits of Quercus pubescens Willd.

Electrodeposited Ionomer Protection Layer for Negative Electrodes in Zinc-Air Batteries.

The protection of zinc anodes in zinc-air batteries (ZABs) is an efficient way to reduce corrosion and Zn dendrite formation and improve cyclability and battery efficiency. Anion-conducting poly(N-vinylbenzyl N,N,N-trimethylammonium)chloride (PVBTMA) thin films were electrodeposited directly on zinc metal using cyclic voltammetry. This deposition process presents a combination of advantages, including selective anion transport in PVBTMA reducing zinc crossover, high interface quality by electrodeposition improving the corrosion protection of zinc and high ionomer stiffness opposing zinc dendrite perforation.

A Short Overview of Biological Fuel Cells.

This short review summarizes the improvements on biological fuel cells (BioFCs) with or without ionomer separation membrane. After a general introduction about the main challenges of modern energy management, BioFCs are presented including microbial fuel cells (MFCs) and enzymatic fuel cells (EFCs). The benefits of BioFCs include the capability to derive energy from waste-water and organic matter, the possibility to use bacteria or enzymes to replace expensive catalysts such as platinum, the high selectivity of the electrode reactions that allow working with less complicated systems, without the need for high purification, and the lower environmental impact.

Nanostructured, Metal-Free Electrodes for the Oxygen Reduction Reaction Containing Nitrogen-Doped Carbon Quantum Dots and a Hydroxide Ion-Conducting Ionomer.

In this work, we studied the combination of nitrogen-doped carbon quantum dots (N-CQD), a hydroxide-ion conducting ionomer based on polysulfone (PSU) and polyaniline (PANI), to explore the complementary properties of these materials in high-performance nanostructured electrodes for the oxygen reduction reaction (ORR) in alkaline solution. N-CQD were made by hydrothermal synthesis from glucosamine hydrochloride (GAH) or glucosamine hydrochloride and N-Octylamine (GAH-Oct), and PSU were quaternized with trimethylamine (PSU-TMA). The nanocomposite electrodes were prepared on carbon paper by drop-casting.

Aliphatic Anion Exchange Ionomers with Long Spacers and No Ether Links by Ziegler-Natta Polymerization: Properties and Alkaline Stability.

In this work we report the synthesis of poly(vinylbenzylchloride-co-hexene) copolymer grafted with N,N-dimethylhexylammonium groups to study the effect of an aliphatic backbone without ether linkage on the ionomer properties. The copolymerization was achieved by the Ziegler-Natta method, employing the complex ZrCl (THF) as a catalyst. A certain degree of crosslinking with N,N,N',N'-tetramethylethylenediamine (TEMED) was introduced with the aim of avoiding excessive swelling in water.

Pharmacological Dissection of the Crosstalk between Na and Ca Channels in GH3b6 Cells.

Thanks to the crosstalk between Na and Ca channels, Na and Ca homeostasis interplay in so-called excitable cells enables the generation of action potential in response to electrical stimulation. Here, we investigated the impact of persistent activation of voltage-gated Na (Na) channels by neurotoxins, such as veratridine (VTD), on intracellular Ca concentration ([Ca]) in a model of excitable cells, the rat pituitary GH3b6 cells, in order to identify the molecular actors involved in Na-Ca homeostasis crosstalk. By combining RT-qPCR, immunoblotting, immunocytochemistry, and patch-clamp techniques, we showed that GH3b6 cells predominantly express the Na1.

Laser Ablation-Assisted Synthesis of Plasmonic Si@Au Core-Satellite Nanocomposites for Biomedical Applications.

Owing to strong plasmonic absorption and excellent biocompatibility, gold nanostructures are among best candidates for photoacoustic bioimaging and photothermal therapy, but such applications require ultrapure Au-based nanoformulations of complex geometry (core-shells, nanorods) in order to shift the absorption band toward the region of relative tissue transparency (650-1000 nm). Here, we present a methodology for the fabrication of Si@Au core-satellite nanostructures, comprising of a Si core covered with small Au nanoparticles (NP), based on laser ablative synthesis of Si and Au NPs in water/ethanol solutions, followed by a chemical modification of the Si NPs by 3-aminopropyltrimethoxysilane (APTMS) and their subsequent decoration by the Au NPs. We show that the formed core-satellites have a red-shifted plasmonic absorption feature compared to that of pure Au NPs (520 nm), with the position of the peak depending on APTMS amount, water-ethanol solvent percentage and Si-Au volume ratio.

Chemometric Discrimination of the Geographical Origin of Three Greek Cultivars of Olive Oils by Stable Isotope Ratio Analysis.

Α stable isotope ratio mass spectrometer was used for stable isotope ratio (i.e., δC, δO, and δH) measurements, achieving geographical discrimination using orthogonal projections to latent structures discriminant analysis.

Thermoelectric Properties of Sb-S System Compounds from DFT Calculations.

By combining density functional theory, quantum theory of atoms in molecules and transport properties calculations, we evaluated the thermoelectric properties of Sb-S system compounds and shed light on their relationships with electronic structures. The results show that, for SbS, the large density of states (DOS) variation induces a large Seebeck coefficient. Taking into account the long-range weak bonds distribution, SbS should exhibit low lattice thermal conductivity.

Controlling Two-Photon Action Cross Section by Changing a Single Heteroatom Position in Fluorescent Dyes.

The optimization of nonlinear optical properties for "real-life" applications remains a key challenge for both experimental and theoretical approaches. In particular, for two-photon processes, maximizing the two-photon action cross section (TPACS), the figure of merit for two-photon bioimaging spectroscopy, requires simultaneously controlling all its components. In the present Letter, a series of difluoroborates presenting various heterocyclic rings as an electron acceptor have been synthesized and their absorption, fluorescence, photoisomerization, and two-photon absorption features have been analyzed using both experimental and theoretical approaches.

CpHMD-Then-QM/MM Identification of the Amino Acids Responsible for the Anabaena Sensory Rhodopsin pH-Dependent Electronic Absorption Spectrum.

Anabaena Sensory Rhodopsin (ASR), a microbial photoactive protein featuring the retinal chromophore in two different conformations, exhibits a pH-dependent electronic absorption spectrum. Using the recently developed CpHMD-then-QM/MM multiscale protocol applied to ASR embedded in a membrane model, the pH-induced changes in its maximum absorption wavelength have been reproduced and analyzed. While the acidic tiny red-shift is essentially correlated with the deprotonation of an aspartic acid located on the ASR extracellular side, the larger blue-shift experimentally reported at pH values larger than 5 involves a cluster of titrating residues sitting on the cytoplasmic side.

Sonochemical synthesis and crystal structure of di-methyl-ammonium bis-[3-carb-oxy-2-(di-methyl-amino)-propano-ato-κ , ]chlorido-chromium(II) monohydrate.

The title complex, [(CH)NH][Cr(CHNO)Cl]·HO, was synthesized sonochemically. The complex anion consists of a chromium(II) ion ligated by two 3-carb-oxy-2-(di-methyl-amino)-propano-ate anions. They coordinate in a bidentate manner, with a carboxyl-ate oxygen atom and the nitro-gen atom to each other in the equatorial plane, while the apical position is occupied by a Cl ion.

"Intrinsic" Anion Exchange Polymers through the Dissociation of Strong Basic Groups: PPO with Grafted Bicyclic Guanidines.

We synthesized anion exchange polymers by a reaction of chloromethylated poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) with strongly basic 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

Cloaking through cancellation of diffusive wave scattering.

A new cloaking mechanism, which makes enclosed objects invisible to diffusive photon density waves, is proposed. First, diffusive scattering from a basic core-shell geometry, which represents the cloaked structure, is studied. The conditions of scattering cancellation in a quasi-static scattering regime are derived.

Molding acoustic, electromagnetic and water waves with a single cloak.

We describe two experiments demonstrating that a cylindrical cloak formerly introduced for linear surface liquid waves works equally well for sound and electromagnetic waves. This structured cloak behaves like an acoustic cloak with an effective anisotropic density and an electromagnetic cloak with an effective anisotropic permittivity, respectively. Measured forward scattering for pressure and magnetic fields are in good agreement and provide first evidence of broadband cloaking.

Thermal invisibility based on scattering cancellation and mantle cloaking.

We theoretically and numerically analyze thermal invisibility based on the concept of scattering cancellation and mantle cloaking. We show that a small object can be made completely invisible to heat diffusion waves, by tailoring the heat conductivity of the spherical shell enclosing the object. This means that the thermal scattering from the object is suppressed, and the heat flow outside the object and the cloak made of these spherical shells behaves as if the object is not present.