BINA

Nanoporous layers are widely spread in nature and among artificial devices. However, complex characterization of extensively nanoporous thin films showing porosity-dependent softening lacks consistency and reliability when using different analytical techniques. We introduce herein, a facile and precise method of such complex characterization by multi-harmonic QCM-D (Quartz Crystal Microbalance with Dissipation Monitoring) measurements performed both in the air and liquids (Au-Zn alloy was used as a typical example). The porosity values determined by QCM-D in air and different liquids are entirely consistent with that obtained from parallel RBS (Rutherford Backscattering Spectroscopy) and GISAXS (Grazing-Incidence Small-Angle Scattering) characterizations. This ensures precise quantification of the nanolayer porosity simultaneously with tracking their viscoelastic properties in liquids, significantly …

Decorating emulsion droplets by particles stabilizes foodstuff and pharmaceuticals. Interfacial particles also influence aerosol formation, thus impacting atmospheric CO2 exchange. While studies of particles at disordered droplet interfaces abound in the literature, such studies for ubiquitous ordered interfaces are not available. Here, we report such an experimental study, showing that particles residing at crystalline interfaces of liquid droplets spontaneously self-position to specific surface locations, identified as structural topological defects in the crystalline surface monolayer. This monolayer forms at temperature T = Ts, leaving the droplet liquid and driving at Td < Ts a spontaneous shape-change transition of the droplet from spherical to icosahedral. The particle’s surface position remains unchanged in the transition, demonstrating these positions to coincide with the vertices of the sphere-inscribed icosahedron …

A frequency‐domain (FD) analysis of fluorescence lifetime (FLT) is a unique and rapid method for cellular and intracellular classifications that can serve for medical diagnostics purposes. Nevertheless, its data analysis process demands nonlinear fitting algorithms that may distort the resolution of the FLT data and hence diminish the classification ability of the method. This research suggests a sample classification technique that is unaffected by the analysis process as it is based on the squared distance (D2) between the raw frequency response data (FRD). In addition, it presents the theory behind this technique and its validation in two simulated data sets of six groups with similar widely and closely spaced FLT data as well as in experimental data of 43 samples from bacterial and viral infected and non‐infected patients. In the two simulated tests, the classification accuracy was above 95% for all six groups. In the …

A quantum walker on a graph, prepared in the state , e.g. initially localized at node , is repeatedly probed, with fixed frequency , to test its presence at some target node until the first successful detection. This is a quantum version of the first-passage problem. We investigate the total detection probability , i.e. the probability to eventually detect the particle after an arbitrary number of detection attempts. It is demonstrated that this total detection probability is less than unity in symmetric systems, where it is possible to find initial states which are shielded from the detector by destructive interference, so-called dark states. The identification of physically equivalent initial states yields an upper bound for in terms of the reciprocal of the number of physically equivalent states. The relevant subgroup of the system's symmetry operations is found to be the stabilizer of the detection state. Using this, we prove that all bright, i.e. surely detectable, states are symmetric with respect to the stabilizer. This implies that can be obtained from a diagonalization of the "symmetrized" Hamiltonian, instead of having to find all eigenstates of the Hamiltonian.

Detection of biomarkers at low concentrations is essential for early diagnosis of numerous diseases. In many sensitive assays, the target molecules are tagged using fluorescently labeled probes and captured using magnetic beads. Magnetic beads facilitate washing and separation steps, are well suited for automation, and improve the assay sensitivity. Current devices rely on quantifying the target molecules by detecting the fluorescence signal from individual beads. Thus, to detect low concentrations of target molecules, these devices require sophisticated optical detectors, making them bulky and expensive. Here, we propose a compact fluorescence-based system that simply uses a small permanent magnet with a conic tip to aggregate the magnetic beads, forming a cluster of fluorescently labeled probes whose fluorescence signal is much greater than that of a single bead. Using the magnetically aggregated …

Operando Sb K–edge X–ray absorption spectroscopy and 57Fe Synchrotron Mössbauer Spectroscopy, used for the first time in the field of operando energy storage materials, assisted by operando magnetic measurements, were combined to clarify the role of iron and antimony in the electrochemical reaction mechanism of FeSb2 as negative electrode material for sodium–ion batteries (SIB). Both datasets were analyzed using an innovative chemometric approach involving principal component analysis (PCA) and multivariate curve resolution – alternating least square analysis (MCR–ALS) yielding new insights on the sodiation reaction. Our findings show that the reaction of Na with FeSb2 during discharge leads to the formation of Na3Sb along with superparamagnetic Fe amorphous nanoparticles which contain small amounts of Sb dissolved in their lattice. During the following desodiation, the pristine material FeSb2 is not recovered while iron nanoparticles grow in size, and continue growing also along the following discharge. Here, even though such iron nanoparticles remain electrochemically inactive, they play a key role in the reduction and stabilization of the polarization as well as in the reversibility of the electrochemical sodiation of antimony.

High solubility of lithium-polysulfides (Li 2 S n) intermediate species in the electrolyte solution in rechargeable lithium-sulfur batteries, results in their reaction with lithium anode to form insoluble lithium polysulfides (PS). These PS sediment on the lithium surface and form new interphase on the lithium anode. Therefore, it is important to investigate the effect of PS dissolution on the reversibility of Li metal stripping/plating. The diffusion of dissolved Li 2 S n and their reduction to PS on the anode, poses the biggest challenge toward the realization of practical Li-S batteries. Due to the need of great focus on cathode design and recently anode protection, the aspect of lithium reversibility in presence of PS is remained overlooked. Here, we designed experimental protocols and study the influence of the PS dissolution and crossover, on the reversibility of Li anode by accurately controlling the lithium source in the cell. Using …

We study the anomalous Hall effect (AHE) and anisotropic magnetoresistance (AMR) in a series of ultra-thin Pt/Co (x)/Pt trilayers (0.1 nm⩽ x⩽ 0.5 nm). We find that the AHE exhibits a significant increase at low temperatures (T). This increase cannot be attributed to a trivial increase in magnetization or resistivity. A similar T dependence is observed in the AMR measurements. Interestingly, these effects show almost no dependence on cobalt thickness. Our measurements indicate that the deviation from common behavior can be attributed to an induced magnetic proximity effect in the Pt layers that increases at low temperatures, in agreement with previous reports. An alternative explanation related to the evolution of a non-continuous magnetic layer is considered as well.

One of the many challenges in the study of chiral nanosurfaces and nanofilms is the design of accurate and controlled nanoscale films with enantioselective activity. Controlled design of chiral nanofilms creates the opportunity to develop chiral materials with nanostructured architecture. Molecular layer deposition (MLD) is an advanced surface-engineering strategy for the preparation of hybrid inorganic–organic thin films, with a desired embedded property; in our study this is chirality. Previous attempts to grow enantioselective thin films were mostly focused on self-assembled monolayers or template-assisted synthesis, followed by removal of the chiral template. Here, we report a method to prepare chiral hybrid inorganic–organic nanoscale thin films with controlled thickness and impressive enantioselective properties. We present the use of an MLD reactor for sequenced vapor deposition to produce enantioselective …

We study the anomalous Hall effect (AHE) and anisotropic magnetoresistance (AMR) in a series of ultra-thin Pt/Co (x)/Pt trilayers (0.1 nm⩽ x⩽ 0.5 nm). We find that the AHE exhibits a significant increase at low temperatures (T). This increase cannot be attributed to a trivial increase in magnetization or resistivity. A similar T dependence is observed in the AMR measurements. Interestingly, these effects show almost no dependence on cobalt thickness. Our measurements indicate that the deviation from common behavior can be attributed to an induced magnetic proximity effect in the Pt layers that increases at low temperatures, in agreement with previous reports. An alternative explanation related to the evolution of a non-continuous magnetic layer is considered as well.

We introduce a large-scale nanoporous metallic network whose building blocks are assembled into an effective nonlinear conductive material, with a considerable conversion efficiency in a wide range of optical wavelengths. The high nonlinear response results from the complexity of the three-dimensional (3D) network structure having a large surface area as well as hot spots in deeper focal plans of the metallic network. Broadband responses of the metallic network are observed by both second harmonic generation (SHG) and cathodoluminescence (CL). The large-scale dimension and generation of randomized hot spots make this 3D metallic network a promising platform for applications like photocatalysis, sensing, or optical imaging such as structured illumination microscopy.

We summarize herein our four years’ experience in application of Electrochemical Quartz Crystal Microbalance with Dissipation Monitoring (EQCM-D) method used to characterize the electrode materials for energy storage and conversion. A special focus of this review is on the fundamental aspects of acoustic probing of electrode films rigidly attached to the surface of a quartz crystal sensor oscillating in thickness shear mode on multiple overtone orders. It is shown that the concept of acoustic load impedance and the related complex frequency change is of key importance to collect and quantitatively analyze diverse information on in situ acoustic properties of real energy storage electrodes. We provide a comprehensive description of the principles of hydrodynamic modeling of acoustic load impedance related to stiff electrodes with complex geometry/morphology (e.g. rough and porous structures), and viscoelastic …

Antimicrobial textiles can contribute to the fighting against antibiotic resistance pathogenic microorganisms. Polypyrrole is a conjugated polymer that exerts a biocidal action thanks to positive charges on its backbone chain produced during it synthesis. In this work, dispersions of stable polypyrrole nanoparticles were produced by chemical oxidative polymerization at room temperature in water. An ultrasound-assisted coating process was then used to effectively treat a polyester fabric with the nanoparticles to obtain an optimal antibacterial coating which efficiently eradicates the bacteria. The results showed that the treated fabric with about 4 g/m2 of polypyrrole had log bacteria reductions of 6.0 against Staphylococcus aureus and 7.5 against Escherichia coli. The combination of a polypyrrole synthesis in the form of water nanoparticles dispersions and a continuous coating of fabrics supported by ultrasound …

Detection of evanescent waves through Near-field Scanning Optical Microscopy (NSOM) has been simulated in the past, using Finite Elements Method (FEM) and 2D advanced simulations of a silicon Schottky diode, shaped as a truncated trapezoid photodetector, and sharing a subwavelength pin hole aperture. Towards enhanced resolution and next applications, the study of polarization’s influence was added to the scanning. The detector has been horizontally shifted across a vertically oriented Gaussian beam while several E-field modes, are projected on the top of the device. Both electrical and electro-optical simulations have been conducted. These results are promising towards the fabrication of a new generation of photodetector devices which can serve for Time-Spectral based Polarization-Encoding for Spatial-Temporal Super-Resolved NSOM Readout, as developed in the study.

Terpene cyclases are responsible for the initial cyclization cascade in the multistep synthesis of a large number of terpenes. CotB2 is a diterpene cyclase from Streptomyces melanosporofaciens, which synthesizes the formation of cyclooctat-9-en-7-ol, a precursor to the next-generation anti-inflammatory drug, cyclooctatin. In this work, we present evidence for a significant role of the active site residues in CotB2 on the reaction energetics using quantum mechanics calculations in an active site cluster model. The results using the active site model reveal the significant effect of the active site residues on the relative electronic energy of the intermediates and transition state (TS) structures with respect to gas phase data. A detailed understanding of the role of the enzyme environment on the CotB2 reaction cascade can provide important

Translocation of mRNA through the nuclear pore complex (NPC) requires interactions with different NPC regions. To determine the interactions that are crucial for effective mRNA export in living cells, we examined mRNA export within individual pores by applying various types of mRNA export blocks that stalled mRNPs at different stages of transition. Focusing on the major mRNA export factor NXF1, we found that initial mRNP binding to the NPC did not require NXF1 in the NPC, whereas release into the cytoplasm did. NXF1 localization in the NPC did not require RNA or RNA binding. Superresolution microscopy showed that NXF1 consistently occupied positions on the cytoplasmic side of the NPC. Interactions with specific nucleoporins were pinpointed using FLIM-FRET for measuring protein–protein interactions inside single NPCs, showing that Dbp5 helicase activity of mRNA release is conserved in yeast and …

Metasurfaces allow unprecedented control of light through engineering the amplitude, phase and polarization across arrays of meta-atom resonators. Adding dynamic tunability to metasurface components would boost their potential and unlock a vast array of new application possibilities such as dynamic beam steering, LIDAR, tunable metalenses and reconfigurable meta-holograms, to name a few. We present here high-index reconfigurable metaatoms, resonators and metasurfaces that can dynamically and continuously tune their frequency, amplitude and phase, across the near to mid-infrared spectral ranges. We highlight the importance of narrow linewidth resonances along with peak performance of tunable mechanisms for efficient and practical reconfigurable devices.

Silicon is predicted to become a significant component of high energy density Li-ion anodes. Mn-based cathodes for Li-ion batteries have been widely investigated in past years and Mn dissolution into the electrolyte, migration, and deposition on the anode’s solid electrolyte interphase present a major challenge. In this work, we intentionally synthesize manganese oxide with several nanoscale thicknesses on a Si nanomaterial and follow the electrochemical behavior of the core–shell nanoparticles as Li-ion anode. The structure of the nanocomposites is investigated using high-resolution scanning electron microscopy, high-resolution transition electron microscopy, X-ray diffraction, and electron paramagnetic resonance. The synthesis yields uniform nanoshells of Mn3O4 haussmanite phase. We demonstrate that the haussmanite phase is electrochemically active, and its presence improves the lithiation process …

THIS JOURNAL OF LIGHTWAVE TECHNOLOGY Special Issue contains expanded versions of selected papers that were presented during the 26th International Conference on Optical Fibre Sensors (OFS-26). From a modest conference, established in 1983 and attended by some tens of pioneers, the International Conference on Optical Fibre Sensors (OFS) has turned in this past decade into a major event gathering more than 500 actors from both the academia and industry. It has thus become an essential event in a community, which finally witnesses years of dedicated research and development translated into widely accepted, commercially available fibre-based sensors, offering unmatched solutions of unique performance in many fields of applications.The 26th edition of this successful conference (https://www. ofs26. org) was held in the glittering scenery of lakes and moun-tains, where the city of Lausanne …

In the past couple of decades great advancements have been made in the development of PGM-free catalysts based on earth-abundant elements, nitrogen, carbon and transition metals (usually Fe or Co), inspired by biological systems such as porphyrins and phthalocyanines.1-6 In order to overcome the poor stability and low catalytic activity of transition-metal complexes, a new class of high temperature-treated (HT-treated) catalysts, composed of the same elements, i.e., a transition metal, carbon and nitrogen, was developed. Although HT-treated PGM-free catalysts exhibit improved activity and stability, their performance remains inferior to PGM catalysts, calling for further improvements to make them a viable alternative to the state-of-the-art materials. In this work, we designed, synthesized and characterized ORR catalysts based on iron, carbon and nitrogen in a well-defined, high surface-area …