BINA

Humidity is often reported to compromise the stability of lead halide perovskites or of devices based on them. Here we measure the humidity dependence of the elastic modulus and hardness for two series of lead halide perovskite single crystals, varying either by cation or by anion type. The results reveal a dependence on bond length between, hydrogen bonding with, and polarizability/polarization of these ions. The results show an intriguing inverse relation between modulus and hardness, in contrast to their positive correlation for most other materials. This anomaly persists and is strengthened by the effect of humidity. This, and our overall findings are ascribed to the materials’ unique atomic-scale structure and properties, viz nano-polar domains and strong dynamic disorder, yet high-quality average order. Our conclusions are based on comparing results obtained from several different nano-indentation …

Metal–semiconductor interfaces are ubiquitous in modern electronics. These quantum-confined interfaces allow for the formation of atomically thin polarizable metals and feature rich optical and optoelectronic phenomena, including plasmon-induced hot-electron transfer from metal to semiconductors. Here, we report on the metal–semiconductor interface formed during the intercalation of zero-valent atomic layers of tin (Sn) between layers of MoS2, a van der Waals layered material. We demonstrate that Sn interaction leads to the emergence of gap states within the MoS2 band gap and to corresponding plasmonic features between 1 and 2 eV (0.6–1.2 μm). The observed stimulation of the photoconductivity, as well as the extension of the spectral response from the visible regime toward the mid-infrared suggests that hot-carrier generation and internal photoemission take place.

Superhydrophobic coatings on polymeric films are in high demand due to their various real-world applications in a number of different fields. However, reported coatings lack durability or have complicated processes rendering them impractical. Here, tetraethylorthosilicate is polymerized via a modified Stöber method in the presence of a corona treated PP film (in-situ) which results in a thin silica-structured layer, covalently bonded to the PP film. Fluorocarbon silanes are then further reacted with the silica layer. The high surface roughness of the silica structures and low surface energy of the fluorocarbon silanes produce superhydrophobic surfaces. PP films coated with flake-like silica structures resulted in higher surface roughness and superhydrophobicity than the particle-like coating. Additionally, the flake-like silica coating exhibited good self-cleaning properties and durability to sandpaper abrasion tests. This …

Li-rich Mn-based layered oxide cathodes with a high discharge capacity hold great promise for high energy density lithium-ion batteries. However, application is hampered by voltage and capacity decay and gas evolution during cycling due to interfacial side reactions. Here, we report coating by oxygen-deficient perovskite La0.9Sr0.1CoO3 using the Pechini process. X-ray photoelectron spectroscopy and scanning transmission electron microscopy both exhibit a uniform coating layer with a high oxygen vacancy concentration. The coating effectively mitigates the first cycle irreversible capacity loss and voltage decay while increasing cyclability. Optimized coating improves capacity retention from 55.6% to 84.8% after 400 cycles at 2 C. Operando differential electrochemical mass spectroscopy shows that such a coating can significantly mitigate the release of oxygen and carbon dioxide. Electrochemical impedance …

A superconducting (SC) mixed state occurs in type-II superconductors where the upper critical field H c 2 is higher than the thermodynamic critical field H c. When an applied field is in between these fields, the free energy depends weakly on the order parameter which therefore can be small (SC state) or zero (normal state) at different parts of the sample. In this paper we demonstrate how a normal state along a line traversing a superconductor can be turned on and off externally in zero field. The concept is based on a long, current-carrying excitation coil, piercing a ring-shaped superconductor. The ring experiences zero field, but the vector potential produced by the coil generates a circular current that destroys superconductivity along a radial line starting at preexisting nucleation points in the sample. Unlike the destruction of superconductivity with magnetic field, the vector potential method is reversible and …

Protein degradation mediated by the ubiquitin-proteasome pathway regulates signaling events in many physiological and pathological conditions. In vitro degradation assays have been instrumental in the understanding of how cell proliferation and other fundamental cellular processes are regulated. These assays are direct, time-specific and highly informative but also laborious, typically relying on low-throughput polyacrylamide gel-electrophoresis followed by autoradiography or immunoblotting. We present protein degradation on chip (pDOC), a MITOMI-based integrated microfluidic technology for discovery and analysis of proteins degradation in cell-free extracts. The platform accommodates hundreds of microchambers on which protein degradation is assayed quickly, simultaneously and using minute amounts of reagents in one or many physiochemical environments. Essentially, pDOC provides a sensitive …

Lithium-ion batteries are commonly charged following the constant current-constant voltage (CC-CV) protocol. Current flow during charging implies an equivalent ionic flow through the battery materials. Intercalation and de-intercalation of Li+ are accompanied by concentration gradients that are reflected by the rise in the cells' potentials that is required to maintain the constant current during the CC regime. In this work, two new pulsed charging protocols were tested. First, a square current pulse is applied to the cell until the cut-off voltage is reached, followed by a pulsed square voltage protocol (PV). The second methodology keeps the same current pulse; however, after the limiting voltage was reached, the pulsing regime consisted in alternating between a maximum voltage value and a minimum, non-zero, constant current value. Different voltage pulse widths and frequencies were tested, in order to study the …

In nanophotonics, small mode volume and high-quality factor (Q-factor) resonances fundamentally scales with high refractive index values. Topological insulators (TI) are a new class of materials possessing narrow bulk bandgap and gapless Dirac surface states, and exhibit ultra high permittivity values. In this work, I will discuss our latest results on Bi2Te3 and Bi2Se3 TI meta-optics. Using polarized far-field and near field Nanospectroscopy we reveal that Bi2Se3 nanobeams exhibit mid-infrared resonant modes with 2pi phase shifts across the resonance. We further demonstrate that Bi2Te3 metasurfaces exhibit deep subwavelength resonant modes utilizing their record high index value peaking at n~11.

Silicon-photonic integrated circuits are a pivotal technology for the continued growth of data communications. A main task of silicon photonics is the wavelength division multiplexing of communication channels to aggregate bandwidths that exceed the working rates available in electronics. In this work, we design and implement a 16-channel, wavelength division multiplexing device in silicon-on-insulator. The device operates at the O-band wavelengths, centered at 1310 nm, which are favored by many data center applications. The spacing between adjacent channels is 0.96 nm (167 GHz), close to those of dense wavelength division multiplexing standards in the 1550 nm wavelength range (C band). The layout consists of 15 Mach-Zehnder interferometers, cascaded in a four-stage tree topology. The differential phase delay within each interferometer is precisely trimmed post-fabrication, through local illumination of a photosensitive upper cladding layer of As 2 Se 3 chalcogenide glass. Trimming is performed subject to closed-loop feedback of transfer functions measurements. The devices can be useful in data center optical communications.

The changes occurring in mRNA organization during nucleo-cytoplasmic transport and export, are not well understood. Moreover, directionality of mRNA passage through the nuclear pore complex (NPC) has not been examined within individual NPCs. Here we find that an mRNP is compact during nucleoplasmic travels compared to a more open structure after transcription and at the nuclear periphery. Compaction levels of nuclear transcripts can be modulated by varying levels of SR proteins and by changing genome organization. Nuclear mRNPs are mostly rod-shaped with distant 5'/3'-ends, although for some, the ends are in proximity. The latter is more abundant in the cytoplasm and can be modified by translation inhibition. mRNAs and lncRNAs exiting the NPC exhibit predominant 5’-first export. In some cases, several adjacent NPCs are engaged in export of the same mRNA suggesting 'gene gating' …

Among extensively studied Li‐ion cathode materials, LiCoO2 (LCO) remains dominant for portable electronic applications. Although its theoretical capacity (274 mAh g−1) cannot be achieved in Li cells, high capacity (≤240 mAh g−1) can be obtained by raising the charging voltage up to 4.6 V. Unfortunately, charging Li‐LCO cells to high potentials induces surface and structural instabilities that result in rapid degradation of cells containing LCO cathodes. Yet, significant stabilization is achieved by surface coatings that promote formation of robust passivation films and prevent parasitic interactions between the electrolyte solutions and the cathodes particles. In the search for effective coatings, the authors propose RbAlF4 modified LCO particles. The coated LCO cathodes demonstrate enhanced capacity (>220 mAh g−1) and impressive retention of >80/77% after 500/300 cycles at 30/45 °C. A plausible mechanism …

The optimal performance of organic electrodes for aqueous batteries requires their full compatibility with selected electrolyte solutions. Electrode materials having 1–3-dimensional structures of variable rigidity possess a confined space in their structure filled with water and electrolyte solutions. Depending on the rigidity and confined space geometry, insertion and extraction of ions into electrode structures are often coupled with incorporation/withdrawal of water molecules. Aside from the scientific interest in understanding the charging mechanism of such systems, co-insertion of solvent molecules affects strongly the charge storage capability of the electrodes for energy storage devices. We present herein in situ electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) investigations of polyaniline (PANI) electrodes operating in various aqueous Na+-containing electrolytes, namely, Na2SO4 …

A superconducting (SC) mixed state occurs in type-II superconductors where the upper critical field H c 2 is higher than the thermodynamic critical field H c. When an applied field is in between these fields, the free energy depends weakly on the order parameter which therefore can be small (SC state) or zero (normal state) at different parts of the sample. In this paper we demonstrate how a normal state along a line traversing a superconductor can be turned on and off externally in zero field. The concept is based on a long, current-carrying excitation coil, piercing a ring-shaped superconductor. The ring experiences zero field, but the vector potential produced by the coil generates a circular current that destroys superconductivity along a radial line starting at preexisting nucleation points in the sample. Unlike the destruction of superconductivity with magnetic field, the vector potential method is reversible and …

The velocity distribution of a classical gas of atoms in thermal equilibrium is the normal Maxwell distribution. It is well known that for sub-recoiled laser cooled atoms L\'evy statistics and deviations from usual ergodic behaviour come into play. Here we show how tools from infinite ergodic theory describe the cool gas. Specifically, we derive the scaling function and the infinite invariant density of a stochastic model for the momentum of laser cooled atoms using two approaches. The first is a direct analysis of the master equation and the second following the analysis of Bertin and Bardou using the lifetime dynamics. The two methods are shown to be identical, but yield different insights into the problem. In the main part of the paper we focus on the case where the laser trapping is strong, namely the rate of escape from the velocity trap is for and . We construct a machinery to investigate the time averages of physical observables and their relation to ensemble averages. The time averages are given in terms of functionals of the individual stochastic paths, and here we use a generalisation of L\'evy walks to investigate the ergodic properties of the system. Exploring the energy of the system, we show that when it exhibits a transition between phases where it is either an integrable or non integrable observable, with respect to the infinite invariant measure. This transition corresponds to very different properties of the mean energy, and to a discontinuous behaviour of the fluctuations. Since previous experimental work showed that both and are attainable we believe that both phases could be explored also experimentally.

Plasmonic nano-objects have shown great potential in enhancing biological and chemical sensing, light harvesting and energy transfer, and optical and quantum computing to name a few. Therefore, an extensive effort has been vested in optimizing plasmonic systems and exploiting their field enhancement properties. Super-resolution imaging with quantum dots (QDs) is a promising method to probe plasmonic near-fields, but is hindered by the distortion of the emission intensity and radiation pattern. Here we investigate the interaction between QDs and 'L-shaped' gold nanoantennas, and demonstrate both theoretically and experimentally that this strong interaction can induce polarization-dependent modifications to the apparent QD emission intensity, polarization and localization. Based on FDTD simulations and polarization-modulated single-molecule microscopy, we show that the displacement of the emitter's localization is due to the interference between the emitter and the induced dipole and can be up to 100 nm. We also discovered that the emission polarization can rotate towards the symmetry axis or one arm of the L-shape because of the scattering. Our results could assist in paving a pathway for higher precision plasmonic near-field mapping and its underlying applications.

The seven-transmembrane superfamily member 3 protein (TM7SF3) is a p53-regulated homeostatic factor that attenuates cellular stress and the unfolded protein response. Here we show that TM7SF3 localizes to nuclear speckles; eukaryotic nuclear bodies enriched in splicing factors. This unexpected location for a trans-membranal protein enables formation of stable complexes between TM7SF3 and pre-mRNA splicing factors including DHX15, LARP7, HNRNPU, RBM14, and HNRNPK. Indeed, TM7SF3 regulates alternative splicing of >330 genes, mainly at the 3’end of introns by directly modulating the activity of splicing factors such as HNRNPK. These effects are observed both in cell lines and primary human pancreatic islets. Accordingly, silencing of TM7SF3 results in differential expression of 1465 genes (about 7% of the human genome); with 844 and 621 genes being up- or down-regulated, respectively …

Copper is an essential element in nature but in excess it is toxic to the living cell. The human metallochaperone Atox1 participates in copper homeostasis and is responsible for copper transmission. In a previous multiscale simulation study, we noticed a change in the coordination state of the Cu(I) ion, from 4 bound cysteine residues to 3, in agreement with earlier studies. Here we perform and analyse classical molecular dynamic simulations of various coordination states: 2, 3, and 4. The main observation is an increase in protein flexibility as a result of a decrease in coordination state. Additionally, we identified several populated conformations that correlate well with double electron‐electron resonance distance distributions or an X‐ray structure of Cu(I)‐bound Atox1. We suggest that the increased flexibility might benefit the process of ion transmission between interacting proteins. Further experiments can …

Increasing the production capacity of electrical energy to fulfill the continuously rising global demand, while simultaneously trying to avoid greenhouse gas emissions in the process, and being environmentally sound, is one of the largest challenges of this era.One way to achieve it is to rely on hydrogen for energy storage. Nowadays, most of the hydrogen produced is mainly from fossil fuels, and the emission of detrimental gasses is only shifted. To get to a true green hydrogen, it is necessary to produce it in emissions-free processes.One method to achieve this is to use renewable energies in combination with electrochemical water electrolyzers, in which two distinct chemical reactions take place: the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER). Both reaction require catalysts to execute at high rates, and while the HER is considered to be relatively facile and takes …

MethodRat pups' brains were dissected and placed on a chilled petri dish. They then entered the experimental protocol. The suspended synaptosomes were divided equally into four experimental groups (control, high potassium" surrogate to hypoxic stimulation," cocaine, and cocaine+ high K). Reversed-phase high-performance liquid chromatography analyzed glutamate with fluorescent detectionResultsThe glutamate level was lowest in the cocaine-only group, with a level of 1.96× 10 4, compared to the control and high potassium group. However, combining cocaine with high potassium seemed to generate a synergistic effect, achieving the highest glutamate level of all groups with a value of 5.31× 10 4.

In this chapter, the analysis of forward stimulated Brillouin scattering in fibers comprised of multiple cores is presented. In such multi-core fibers, guided acoustic waves may be stimulated by optical fields in one core and induce photoelastic scattering of light waves in a different one. The photoelastic scattering leads to cross-phase modulation among optical fields in spatially distinct cores, which is mediated by the stimulation of guided acoustic modes. Cross-phase modulation may take place even among cores that are spaced far apart, where the direct coupling of optical power is arbitrarily weak. The process is quantified in terms of the spectrum of forward Brillouin scattering coefficient, defined earlier with respect to single-mode fibers. The spectrum of cross-phase modulation between the inner, on-axis core and an outer, off-axis core is mediated by guided acoustic modes of radial symmetry and torsional-radial …

In the first chapter of this book, the opto-mechanical effect of forward Brillouin scattering is introduced within a broader context of propagation effects in fibers and of interactions between optical and acoustic waves. A review of linear and nonlinear scattering phenomena is provided, including the mechanisms of Rayleigh, Raman, and Brillouin scattering, and the optical Kerr effect. Scattering from short-period and long-period grating devices is discussed as well. The potential applications and implications of the various mechanisms in optical fiber communications, sensing, signal processing, and lasing are briefly addressed. Next, the physical principles of opto-mechanics are introduced. These include the stimulation of elastic waves by electrostrictive bulk forces and radiation pressures and the scattering of optical waves through photoelasticity and moving boundary effects. Specific formalisms are developed for the …