BINA

Disordered quantum systems feature an energy scale known as the Thouless energy. For energy ranges below this scale, the properties of the energy spectrum can be described by random matrix theory. Above this scale a different behavior sets in. For a metallic system it was shown long ago by Altshuler and Shklovskii [Sov. Phys. JETP 64, 127 (1986)] that the number variance should increase as a power law with power dependent on only the dimensionality of the system. Although tantalizing hints at this behavior were seen in previous numerical studies, it is quite difficult to verify this prediction using the standard local unfolding methods. Here we use a different unfolding method, ie, singular value decomposition, and establish a connection between the power law behavior of the scree plot (the singular values ranked by their amplitude) and the power law behavior of the number variance. Thus, we are able to …

Disordered quantum systems feature an energy scale known as the Thouless energy. For energy ranges below this scale, the properties of the energy spectrum can be described by random matrix theory. Above this scale a different behavior sets in. For a metallic system it was shown long ago by Altshuler and Shklovskii [Sov. Phys. JETP 64, 127 (1986)] that the number variance should increase as a power law with power dependent on only the dimensionality of the system. Although tantalizing hints at this behavior were seen in previous numerical studies, it is quite difficult to verify this prediction using the standard local unfolding methods. Here we use a different unfolding method, ie, singular value decomposition, and establish a connection between the power law behavior of the scree plot (the singular values ranked by their amplitude) and the power law behavior of the number variance. Thus, we are able to …

Graphene unique physicochemical properties made it prominent among other allotropic forms of carbon, in many areas of research and technological applications. Interestingly, in recent years, many studies exploited the use of graphene family nanomaterials (GNMs) for biomedical applications such as drug delivery, diagnostics, bioimaging, and tissue engineering research. GNMs are successfully used for the design of scaffolds for controlled induction of cell differentiation and tissue regeneration. Critically, it is important to identify the more appropriate nano/bio material interface sustaining cells differentiation and tissue regeneration enhancement. Specifically, this review is focussed on graphene‐based scaffolds that endow physiochemical and biological properties suitable for a specific tissue, the nervous system, that links tightly morphological and electrical properties. Different strategies are reviewed to exploit …

Inactivating mutations in the Methyl-CpG Binding Protein 2 (MECP2) gene are the main cause of Rett syndrome (RTT). Despite extensive research into MECP2 function, no treatments for RTT are currently available. Here, we used an evolutionary genomics approach to construct an unbiased MECP2 gene network, using 1028 eukaryotic genomes to prioritize proteins with strong co-evolutionary signatures with MECP2. Focusing on proteins targeted by FDA-approved drugs led to three promising targets, two of which were previously linked to MECP2 function (IRAK, KEAP1) and one that was not (EPOR). The drugs targeting these three proteins (Pacritinib, DMF, and EPO) were able to rescue different phenotypes of MECP2 inactivation in cultured human neural cell types, and appeared to converge on Nuclear Factor Kappa B (NF-kB) signaling in inflammation. This study highlights the potential of comparative genomics to accelerate drug discovery, and yields potential new avenues for the treatment of RTT.

Here we report a type of dynamic effect that is at the core of the so called “counterfactual computation” and especially “counterfactual communication” quantum effects that have generated a lot of interest recently. The basic feature of these counterfactual setups is the fact that particles seem to be affected by actions that take place in locations where they never (more precisely, only with infinitesimally small probability) enter. Specifically, the communication/computation takes place without the quantum particles that are supposed to be the information carriers travelling through the communication channel or entering the logic gates of the computer. Here we show that something far more subtle is taking place: It is not necessary for the particle to enter the region where the controlling action takes place; it is enough for the controlled property of the particle,(ie, the property that is being controlled by actions in the control …

In sufficiently strong scattering media, light transport is suppressed and modes are exponentially localized. Anderson-like localized states have long been recognized as potential candidates for high-Q optical modes for low-threshold, cost-effective random lasers. Operating in this regime remains, however, a challenge since Anderson localization is difficult to achieve in optics, and nonlinear mode interaction compromises its observation. Here, we exhibit individually each lasing mode of a low-dimension solid-state random laser by applying a non-uniform optical gain. By undoing gain competition and cross-saturation, we demonstrate that all lasing modes are spatially localized. We find that selective excitation significantly reduces the lasing threshold, while lasing efficiency is greatly improved. We show further how their spatial locations are critical to boost laser power efficiency. By …

We investigate a tight binding quantum walk on a graph. Repeated stroboscopic measurements of the position of the particle yield a measured "trajectory", and a combination of classical and quantum mechanical properties for the walk are observed. We explore the effects of the measurements on the spreading of the packet on a one dimensional line, showing that except for the Zeno limit, the system converges to Gaussian statistics similarly to a classical random walk. A large deviation analysis and an Edgeworth expansion yield quantum corrections to this normal behavior. We then explore the first passage time to a target state using a generating function method, yielding properties like the quantization of the mean first return time. In particular, we study the effects of certain sampling rates which cause remarkable change in the behavior in the system, like divergence of the mean detection time in finite systems and a decomposition of the phase space into mutually exclusive regions, an effect that mimics ergodicity breaking, whose origin here is the destructive interference in quantum mechanics. For a quantum walk on a line we show that in our system the first detection probability decays classically like , this is dramatically different compared to local measurements which yield a decay rate of , indicating that the exponents of the first passage time depends on the type of measurements used.

We present measurements of the polarization dependencies of the x-ray signal photons generated by the effect of parametric down-conversion of x rays into ultraviolet radiation. The results exhibit pronounced discrepancies with the classical model for the nonlinearity but qualitatively agree with a recently developed quantum mechanical theory for the nonlinear interaction. Our work shows that the reconstruction of the atomic scale charge distribution of valence electrons in crystals by using nonlinear interaction between x rays and longer wavelength radiation, as was suggested in previous works, requires the knowledge of polarization of the generated x-ray signal beam. The results presented in this work indicate a methodology for the study of properties of the Wannier functions in crystals.

Copper is essential for proper functioning of cells but is dangerous in unregulated concentrations. One of the members in the bacterial system responsible for facilitating copper homeostasis is the copper efflux regulator (CueR) protein. Upon copper binding, CueR induces transcription of additional copper homeostasis proteins via a cascade of events. There are some available crystal structures of CueR, in the holo (copper-bound), active (copper- and DNA-bound), and repressed (only DNA-bound) states, and these structures suggest that transcription initiation involves a distortion in the promoter DNA strand. In this work, we study the dynamic behavior of the protein, using molecular dynamics simulations, and compare with available electron paramagnetic resonance measurements for validation. We develop simple force-field parameters to describe the copper-binding motif, thus enabling the use of simplified …

Zinc-based batteries are gaining attention as a promising candidate for large-scale energy storage systems due to their safety, abundance of elemental zinc, low cost, and ease of handling in air. However, only a few zinc storage materials, namely, intercalation cathode materials, were reported, and there is a need to develop host structures with improved performance. Here, we investigate copper vanadate as a cathode material and uncover its proton and zinc storage behavior by combined electrochemical characterization, XRD analysis, and ion migration barrier calculations for the cation diffusion pathways. The material showed a highly reversible capacity of ∼315 mA h/g at 20 mA/g with a good capacity retention.

The functionality of a nanoscale silicon-based optoelectronic modulator is deeply analyzed while it appears that two competing processes, thermal and photonic, are occurring at the same time, and are preventing the optimization of the electro-optics coupling. While an incident illumination-beam first process is translated into photons, generating pairs of electrons-holes, a second process of thermal generation, creating phonons enables a loss of energy. Complementary studies, combining strong analytical models and numerical simulations, enabled to better understand this competition between photonic and thermal activities, in order to optimize the modulator. Moreover, in order to prevent unnecessary heating effects and to present a proposed solution, a picosecond pulsed laser is suggested and demonstrated as the ultimate solution so no energy will be wasted in heat, and still the photonic energy will be fully used. First everanalytical solution to the heating produced due to the laser illumination applied on a nano-photonic device, while the illumination is produced in a periodic time changing function, eg a pulsed illumination, is presented. The present case study and proposed adapted solution can serve as a basis of generic approach in sensors’ activation towards optimized photonics absorption.

Protein immobilization on material surfaces is emerging as a powerful tool in the design of devices and active materials for biomedical and pharmaceutical applications as well as for catalysis. Preservation of the protein’s biological functionality is crucial to the design process and is dependent on the ability to maintain its structural and dynamical integrity while removed from the natural surroundings. The scientific techniques to validate the structure of immobilized proteins are scarce and usually provide limited information as a result of poor resolution. In this work, we benchmarked the ability of standard solid-state NMR techniques to resolve the effects of binding to dissimilar silica materials on a model protein. In particular, the interactions between ubiquitin and the surfaces of MCM41, SBA15, and silica formed in situ were tested for their influence on the structure and dynamics of the protein. It is shown that the …

High‐voltage all‐solid‐state lithium batteries (HVASSLBs) are considered attractive systems for portable electronics and electric vehicles, due to their theoretically high energy density and safety. However, realization of HVASSLBs with sulfide solid electrolytes (SEs) is hindered by their limited electrochemical stability, resulting in sluggish interphase dynamics. Here, a bidirectionally compatible buffering layer design scheme is proposed to overcome the interfacial challenges of sulfide‐based HVASSLBs. As a proof of concept, it is found that NASICON‐type LixZr2(PO4)3 surprisingly exhibit great compatibility with both 4.5 V LiCoO2 and Li6PS5Cl, based on the results of first‐principles calculations and various in situ/ex situ characterizations. This compatibility significantly restrains the interface reactivity and boosts interfacial Li‐ion transport. Therefore, 4.5 V sulfide‐based HVASSLBs can exhibit remarkably …

Zinc-based batteries are gaining attention as a promising candidate for large-scale energy storage systems due to their safety, abundance of elemental zinc, low cost, and ease of handling in air. However, only a few zinc storage materials, namely, intercalation cathode materials, were reported, and there is a need to develop host structures with improved performance. Here, we investigate copper vanadate as a cathode material and uncover its proton and zinc storage behavior by combined electrochemical characterization, XRD analysis, and ion migration barrier calculations for the cation diffusion pathways. The material showed a highly reversible capacity of ∼315 mA h/g at 20 mA/g with a good capacity retention.

The spillover of animal coronaviruses (aCoVs) to humans has caused SARS, MERS, and COVID-19. While antibody responses displaying cross-reactivity between SARS-CoV-2 and seasonal/common cold human coronaviruses (hCoVs) have been reported, potential cross-reactivity with aCoVs and the diagnostic implications are incompletely understood. Here, we probed for antibody binding against all seven hCoVs and 49 aCoVs represented as 12,924 peptides within a phage-displayed antigen library. Antibody repertoires of 269 recovered COVID-19 patients showed distinct changes compared to 260 unexposed pre-pandemic controls, not limited to binding of SARS-CoV-2 antigens but including binding to antigens from hCoVs and aCoVs with shared motifs to SARS-CoV-2. We isolated broadly reactive monoclonal antibodies from recovered COVID-19 patients that bind a shared motif of SARS-CoV-2, hCoV …

Calcium-based battery systems are promising postlithium candidates; however, only a few amenable calcium materials were reported in nonaqueous electrolytes. Here, reversible storage of Ca2+ ions in aqueous and nonaqueous electrolyte solutions is shown for crystalline 3,4,9,10-perylene tetracarboxylic dianhydride. The carbonyl functional groups and the π-electrons constitute redox centers, which can reversibly interact with divalent ions. This phenomenon was clearly uncovered by combined electrochemistry, Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and ex situ X-ray diffraction analyses. Very promising calcium storage performances are shown with a highly reversible capacity around ∼158 mAh g–1 at a rate of 10 mA g–1 with an average voltage of ∼2.3 V band sufficient capacity retention in saturated Ca …

Understanding the charge transport properties of proteins at the molecular scale is crucial for the development of novel bioelectronic devices. In this contribution, we report on the preparation and electrical characterization of thin films of bacteriorhodopsin grafted on the surface of titanium nitride via aminophosphonate linkers. Thickness analysis using atomic force microscopy revealed a protein film thickness of 8.2±1.5 nm, indicating the formation of a protein bilayer. Electrical measurements were carried out in the dry state, in a vertical arrangement with a eutectic gallium-indium (EGaIn) or an evaporated Ti/Au top contact. DC current-voltage measurements yielded comparable effective tunneling decay constants for the EGaIn top contact and for the Ti/Au top contact. The results presented herein may establish a novel platform for studying charge transport via protein molecules in a solid-state …

Understanding the charge transport properties of proteins at the molecular scale is crucial for the development of novel bioelectronic devices. In this contribution, we report on the preparation and electrical characterization of thin films of bacteriorhodopsin grafted on the surface of titanium nitride via aminophosphonate linkers. Thickness analysis using atomic force microscopy revealed a protein film thickness of 8.2±1.5 nm, indicating the formation of a protein bilayer. Electrical measurements were carried out in the dry state, in a vertical arrangement with a eutectic gallium-indium (EGaIn) or an evaporated Ti/Au top contact. DC current-voltage measurements yielded comparable effective tunneling decay constants for the EGaIn top contact and for the Ti/Au top contact. The results presented herein may establish a novel platform for studying charge transport via protein molecules in a solid-state …

We study the aberrations of four-wave mixing based time lenses resulting from the cross-phase modulations of the pump wave. These temporal aberrations have no spatial equivalent and are important when imaging weak signals with strong pump waves. We show that as the pump power increases, the cross-phase modulations of the pump are responsible for shifting, defocusing, and imposing temporal coma aberrations on the image. We present experimental results of these aberrations with high agreement to analytical and numerical calculations.