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Sep 2020 • Journal of Solid State Electrochemistry

Selected future tasks in electrochemical research related to advanced power sources

David Malka, Netanel Shpigel, Ran Attias, Doron Aurbach

The purpose of this short paper is to outline important research tasks related to electrochemical power sources. In fact, we can mention four main avenues related to electrochemical science connected to energy challenges, ie energy harvesting by photovoltaic cells, hydrogen economy (hydrogen production by electrolysis, followed by its effective storage and use in fuel cells), the energy-water nexus which is related to capacitive interactions (including important topics such as capacitive deionisation and the field of supercapacitors and related devices) and electrochemical energy storage and conversion by batteries.

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Sep 2020 • Developmental Neurobiology

SEM/FIB Imaging for Studying Neural Interfaces

Itai Henn, Ayelet Atkins, Amos Markus, Gal Shpun, Hannah‐Noa Barad, Nairouz Farah, Yossi Mandel

Tissue and neural engineering for various regenerative therapies are rapidly growing fields. Of major interest is studying the complex interface between cells and various 3D structures by scanning electron microscopy with focused ion beam. Notwithstanding its unrivaled resolution, the optimal fixation, dehydration, and staining protocols of the samples while preserving the complex cell interface in its natural form, are highly challenging. The aim of this work was to compare and optimize staining and sample drying procedures in order to preserve the cells in their “life‐like state” for studying the cell interface with either 3D well‐like structures or gold‐coated mushroom‐shaped electrodes. The process involved chemical fixation using a combination of glutaraldehyde and formaldehyde, followed by gentle drying techniques in which we compared four methods: (critical point drying, hexamethyldisiloxane, repeats of …

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Sep 2020 • Journal of The Electrochemical Society

Stabilization of Lithium Cobalt Phosphate Cathodes via Artificial Interphases

Sarah Taragin, Jan L Allen, Lin Ma, Malachi Noked, Marshall A Schroeder

Olivine LiCoPO 4 (LCP) exhibits a rare combination of high theoretical capacity (167 mAh g− 1), excellent thermal stability, and high redox potential (4.8 V vs vs Li/Li+), making it a promising candidate for high voltage lithium batteries. Despite these attractive properties, practical implementation of this electrode chemistry has been limited by stability issues at the cathode-electrolyte interface, including parasitic electrolyte reactions, surface decomposition of the electrode material, and Co dissolution. Carbon coating and substitutions of Co by Fe and other cations improve the performance, however the cycling stability needs further improvement. In an effort to address these issues, we deposited thin, conformal metal oxide surface coatings on substituted LCP powder and investigated the effects of these coatings on the performance of carbon-coated substituted LCP/MCMB graphite full cells with a standard carbonate …

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Sep 2020 • Scientific reports

Osteopontin regulates biomimetic calcium phosphate crystallization from disordered mineral layers covering apatite crystallites

Taly Iline-Vul, Raju Nanda, Borja Mateos, Shani Hazan, Irina Matlahov, Ilana Perelshtein, Keren Keinan-Adamsky, Gerhard Althoff-Ospelt, Robert Konrat, Gil Goobes

Details of apatite formation and development in bone below the nanometer scale remain enigmatic. Regulation of mineralization was shown to be governed by the activity of non-collagenous proteins with many bone diseases stemming from improper activity of these proteins. Apatite crystal growth inhibition or enhancement is thought to involve direct interaction of these proteins with exposed faces of apatite crystals. However, experimental evidence of the molecular binding events that occur and that allow these proteins to exert their functions are lacking. Moreover, recent high-resolution measurements of apatite crystallites in bone have shown that individual crystallites are covered by a persistent layer of amorphous calcium phosphate. It is therefore unclear whether non-collagenous proteins can interact with the faces of the mineral crystallites directly and what are the consequences of the presence of a disordered …

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Sep 2020 • ACS omega

Synthesis and Characterization of Poly (RGD) Proteinoid Polymers and NIR Fluorescent Nanoparticles of Optimal d, l-Configuration for Drug-Delivery Applications—In Vitro Study

Elad Hadad, Safra Rudnick-Glick, Igor Grinberg, Michal Kolitz-Domb, Jordan H Chill, Shlomo Margel

RGD sequence is a tripeptide composed of three amino acids: arginine (R), glycine (G), and aspartic acid (D). The RGD peptide has a high affinity to the integrin alpha v beta 3, which is overexpressed on the membrane of many cancer cells and is attracted to areas of angiogenesis. Proteinoids are biodegradable polymers based on amino acids which are formed by bulk thermal step-growth polymerization mechanism. Hollow proteinoid nanoparticles (NPs) may be formed via self-assembly process of the proteinoid polymers. We propose using novel RGD-based proteinoid polymers to manufacture NPs in which the RGD motif is self-incorporated in the proteinoid backbone. Such P(RGD) NPs can act both as a drug carrier (by encapsulation of a desired drug) and as a targeting delivery system. This article presents the synthesis of four RGD proteinoids with different RGD optical configurations, (d) or (l) arginine …

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Sep 2020 • Carbohydrate Polymers

Antibacterial activities of microwave-assisted synthesized polypyrrole/chitosan and poly (pyrrole-N-(1-naphthyl) ethylenediamine) stimulated by C-dots

Moorthy Maruthapandi, Kusha Sharma, John HT Luong, Aharon Gedanken

Polypyrrole grafted with chitosan (PPy-g-CS) and poly (pyrrole-N-(1-naphthyl) ethylenediamine, a copolymer, (COP) have been synthesized by a one-step microwave procedure with carbon dots(C-Dots) as initiators. The electrostatic interaction between the positively charged polymers and negatively charged microbial cell membranes is widely anticipated to be responsible for cellular lysis. However, Escherichia coli exposed to PPy-g-CS (zeta potential = +46.9 mV) was completely perished after 3 h while COP (zeta potential = +64.1 mV) exhibited no antimicrobial effect. The two polymers were capable of eradicating Staphylococcus aureus, implying the charged effect is the main mechanism of cell death. The two polymers could also chelate calcium and other nutrients as well as form an external barrier to suppress the penetration of essential nutrients to support microbial survival and proliferation. In particular …

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Sep 2020 • Advanced Functional Materials

Rationally Designed Vanadium Pentoxide as High Capacity Insertion Material for Mg‐Ion

Ayan Mukherjee, Sarah Taragin, Hagit Aviv, Ilana Perelshtein, Malachi Noked

Owing to high energy density and economic viability, rechargeable Mg batteries are considered alternatives to lithium ion batteries. However besides the chevrel phase, none of the conventional inorganic cathode materials demonstrate reversible intercalation/deintercalation of Mg+2 ions in an anhydrous electrolyte system. The lack of high voltage and high capacity cathode frustrates the realization of Mg batteries. Previous studies indicate that vanadium pentoxide (V2O5) has the potential to reversibly insert/extract Mg ions. However, many attempts to utilize V2O5 demonstrate limited electrochemical response, due to hindered Mg ion mobility in solid. Here, monodispersed spherical V2O5 with a hierarchical architecture is rationally designed, through a facile and scalable approach. The V2O5 spheres exhibit initial discharge capacity of 225 mA h g−1 which stabilizes at ≈190 mA h g−1 at 10 mA g−1, much higher …

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Sep 2020 • Engineering Research Express

Analyzing the requirements of high-speed camera parameters for enhanced laser speckle sensing of flow dynamics

Mark Golberg, Ran Califa, Javier Garcia, Zeev Zalevsky

A novel method for optimizing fast camera parameters to sense flow dynamics is presented. A wide-field statistic of the temporal auto-correlation intensity function from sample back-scattered laser light can be obtained from the high-end fast cameras that have come on to the market in recent years. Although these statistics can reveal flow dynamics within different sample regions, these cameras can be very costly. Here we investigated the impact of several key camera features such as camera frame rate, sensor exposure time, etc, on the output data (auto-correlation decay time and function fit models). The post-processing algorithm steps are described in detail, followed by the findings from in-vitro and in-vivo experiments investigating ways to re-leaf the camera parameters. The experimental results define fast-camera minimum specification requirements for the correct monitoring of normal blood flow conditions …

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Sep 2020 • Photonics

The significance of carrier leakage for stable lasing in split-well direct phonon terahertz quantum cascade lasers

Nathalie Lander Gower, Silvia Piperno, Asaf Albo

We studied the temperature performance of split-well direct phonon terahertz quantum cascade lasers and found that it is limited by a lasing instability that becomes significant as the temperature increases. When the hot electrons of the upper laser level cannot scatter effectively to excited states due to the high radiative barriers of the structures, a lasing instability occurs, which limits the temperature performance. View Full-Text

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Sep 2020 • Journal of functional biomaterials

Antimicrobial properties of the polyaniline composites against Pseudomonas aeruginosa and Klebsiella pneumoniae

Moorthy Maruthapandi, Arumugam Saravanan, John HT Luong, Aharon Gedanken

CuO, TiO 2, or SiO 2 was decorated on polyaniline (PANI) by a sonochemical method, and their antimicrobial properties were investigated for two common Gram-negative pathogens: Pseudomonas aeruginosa (PA) and Klebsiella pneumoniae (KP). Without PANI, CuO, TiO 2, or SiO 2 with a concentration of 220 µg/mL exhibited no antimicrobial activities. In contrast, PANI-CuO and PANI-TiO 2 (1 mg/mL, each) completely suppressed the PA growth after 6 h of exposure, compared to 12 h for the PANI-SiO 2 at the same concentration. The damage caused by PANI-SiO 2 to KP was less effective, compared to that of PANI-TiO 2 with the eradication time of 12 h versus 6 h, respectively. This bacterium was not affected by PANI-CuO. All the composites bind tightly to the negative groups of bacteria cell walls to compromise their regular activities, leading to the damage of the cell wall envelope and eventual cell lysis. View Full-Text

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Sep 2020 • ChemPhysChem

Nanoscale Structure in Short‐Chain Ionic Liquids

Diego Pontoni, Marco DiMichiel, Moshe Deutsch

The temperature (T) and cationic chain length (n) evolution of the nanoscale structure of the sub‐layering‐threshold members of a model family of room temperature ionic liquids (RTILs) is investigated by x‐ray scattering. The measured curves are computer‐resolved into individual Teubner‐Strey‐like lineshapes. The polar‐apolar layering is found to start at . Opposite n‐trends are found at for the spacings and correlation lengths associated with the diffraction patterns’ two main peaks, and assigned to a shift of balance between the two main interactions, Coulomb and van der Waals, and to increasing packing constraints due to the addition of methylenes. The spacings’ thermal expansion coefficients are found to deviate from the macroscopically‐measured values, and to anomalously decrease with increasing temperature. Finally, the reduced temperature scale, , ( melting temperature), is demonstrated to render …

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Sep 2020 • Chaos, Solitons & Fractals

Infinite ergodic theory meets Boltzmann statistics

Erez Aghion, David A Kessler, Eli Barkai

We investigate the overdamped stochastic dynamics of a particle in an asymptotically flat external potential field, in contact with a thermal bath. For an infinite system size, the particles may escape the force field and diffuse freely at large length scales. The partition function diverges and hence the standard canonical ensemble fails. This is replaced with tools stemming from infinite ergodic theory. Boltzmann-Gibbs statistics, even though not normalized, still describes integrable observables, like energy and occupation times. The Boltzmann infinite density is derived heuristically using an entropy maximization principle, as well as via a first-principles calculation using an eigenfunction expansion in the continuum of low-energy states. A generalized virial theorem is derived, showing how the virial coefficient describes the delay in the diffusive spreading of the particles, found at large distances. When the process is non …

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Sep 2020 • Gut microbes

β-arrestin 2 quenches TLR signaling to facilitate the immune evasion of EPEC

Zijuan Chen, Ruixue Zhou, Yihua Zhang, Doudou Hao, Yu Wang, Shichao Huang, Ningning Liu, Chunmei Xia, Nissan Yissachar, Feng Huang, Yiwei Chu, Dapeng Yan

The protein translocated intimin receptor (Tir) from enteropathogenic Escherichia coli shares sequence similarity with the host cellular immunoreceptor tyrosine-based inhibition motifs (ITIMs). The ITIMs of Tir are required for Tir-mediated immune inhibition and evasion of host immune responses. However, the underlying molecular mechanism by which Tir regulates immune inhibition remains unclear. Here we demonstrated that β-arrestin 2, which is involved in the G-protein-coupled receptor (GPCR) signal pathway, interacted with Tir in an ITIM-dependent manner. For the molecular mechanism, we found that β-arrestin 2 enhanced the recruitment of SHP-1 to Tir. The recruited SHP-1 inhibited K63-linked ubiquitination of TRAF6 by dephosphorylating TRAF6 at Tyr288, and inhibited K63-linked ubiquitination and phosphorylation of TAK1 by dephosphorylating TAK1 at Tyr206, which cut off the downstream signal …

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Aug 2020 • Nature communications

Synchronization of complex human networks

Shir Shahal, Ateret Wurzberg, Inbar Sibony, Hamootal Duadi, Elad Shniderman, Daniel Weymouth, Nir Davidson, Moti Fridman

The synchronization of human networks is essential for our civilization and understanding its dynamics is important to many aspects of our lives. Human ensembles were investigated, but in noisy environments and with limited control over the network parameters which govern the network dynamics. Specifically, research has focused predominantly on all-to-all coupling, whereas current social networks and human interactions are often based on complex coupling configurations. Here, we study the synchronization between violin players in complex networks with full and accurate control over the network connectivity, coupling strength, and delay. We show that the players can tune their playing period and delete connections by ignoring frustrating signals, to find a stable solution. These additional degrees of freedom enable new strategies and yield better solutions than are possible within current models such as the …

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Aug 2020 • Biotechnology Advances 44, 107611, 2020

Remotely controlled magneto-regulation of therapeutics from magnetoelastic gel matrices

Sayan Ganguly, Shlomo Margel

Surface active magnetic nanoparticles especially superparamagnetic iron oxides are already occupying a major domain in medical therapeutics. Arresting of these magnetic nanoparticles into polymer hydrogel is a spatial assembly of nanoparticles that serves the precise delivery of drug molecules. Magnetic hydrogels are very less cultured area still in the biomedical field. This review embraces how the external magnetic field (either static or oscillating) affects the payload release from the hydrogel matrix and their magneto-regulative deformation. Besides these, we also discussed how the ferrosponge and biphasic ferrogel based scaffold type systems impact over the release kinetics and tunability of drug release behaviours.

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Aug 2020 • arXiv preprint arXiv:2008.04085

Gain As configurable disorder-adaptive pumping for control of multimode fiber amplifiers and lasers

Tom Sperber, Vincent Billault, Bernard Dussardier, Sylvain Gigan, Patrick Sebbah

Media featuring both optical gain and disorder, such as random lasers, represent formidable challenges as subjects of research due to the high complexity of the light propagation within them; however, dramatic advances in this nascent field have been furnished by the paradigm of applying wavefront shaping techniques to the beam pumping the system. We present here a theoretical and experimental study employing this approach in a gain medium where the disorder arises not from random scattering but rather from the multimodality of a waveguide: an amplifying multimode fiber. The shaping of the core-guided pump prior to its injection affects the complex, speckle-like patterns of excitation within the fiber volume. Thus we are offered the intriguing prospect of manipulating the spatially heterogeneous gain in a system where the disorder, albeit highly complex, may be fully understood in terms of the discrete eigenmodes of a well-known waveguide. We study our medium in two different configurations: as an optical amplifier, and as a fiber laser. In the first configuration we show that dependence upon the pump configuration, of the amplifier transmission function, surprisingly survives several physical mechanisms which at first sight would appear to severely limit it. This insight is then carried on to the lasing cavity configuration, where we find striking parallels between the behavior of the system and that of random lasers; more importantly, the pump shaping shows a strong ability to control the complex emission, in particular - to selectively favor individual spectral lines and stabilize single-mode operation.

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Aug 2020 • ChemistrySelect

Boosting Electrocatalytic Hydrogen Evolution of Nickel foam Supported Nickel Hydroxide by Ruthenium Doping

Hari Krishna Sadhanala, Ilana Perelshtein, Aharon Gedanken

Hydrogen evolution reaction (HER) in acid electrolytes has advantages for electrolysis of water due to large supply of hydrogen ions. Herein, we report the synthesis of ruthenium doped nickel hydroxide on commercial nickel foam (Ru−Ni(OH)2/NF) by using simple hydrothermal method. Due to integrated assembly and porous structure, as prepared Ru−Ni(OH)2/NF is explored as an electrocatalyst for HER in 0.5 M H2SO4 solution at room temperature. The Ru−Ni(OH)2/NF showed excellent electrocatalytic HER activity with Tafel slope of 94 mV/dec. The overpotential of Ru−Ni(OH)2/NF required to deliver 10 mAcm−2 current density was calculated to be 27 mV, which is smaller than that of commercial Pt/C/NF catalyst (33 mV). Furthermore, the Ru−Ni(OH)2/NF has shown decent stability and notable durability. The enhanced HER activity of Ru−Ni(OH)2/NF is attributed to Ru doping Ni(OH)2/NF and effective …

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Aug 2020 • Acta Biomaterialia

Peptides from diatoms and grasses harness phosphate ion binding to silica to help regulate biomaterial structure

Nurit Adiram-Filiba, Yasmin Geiger, Santosh Kumar, Keren Keinan-Adamsky, Rivka Elbaum, Gil Goobes

Many life forms generate intricate submicron biosilica structures with various important biological functions. The formation of such structures, from the silicic acid in the waters and in the soil, is thought to be regulated by unique proteins with high repeats of specific amino acids and unusual sidechain modifications.Some silicifying proteins are characterized by high prevalence of basic amino acids in their primary structures. Lysine-rich domains are found, for instance, in diatom silaffin proteins and in the sorghum grass siliplant1 protein. These domains exhibit catalytic activity in silica chain condensation, owing to molecular interactions of the lysine amine groups with the forming mineral. The use of amine chemistry by two very remote organisms has motivated us to seek other molecular biosilicification processes that may be common to the two life forms.In diatom silaffins, domains rich in phosphoserine residues are …

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Aug 2020 • Optics Express

X-ray imaging of fast dynamics with single-pixel detector

O Sefi, Y Klein, E Strizhevsky, IP Dolbnya, S Shwartz

We demonstrate experimentally the ability to use a single-pixel detector for two-dimensional high-resolution x-ray imaging of fast dynamics. We image the rotation of a spinning chopper at 100 kHz and at spatial resolution of about 40 microns by using the computational ghost imaging approach. The technique we develop can be used for the imaging of fast dynamics of periodic and periodically stimulated effects with a large field of view and at low dose.

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Aug 2020 • ChemistrySelect

Boosting Electrocatalytic Hydrogen Evolution of Nickel foam Supported Nickel Hydroxide by Ruthenium Doping

Hari Krishna Sadhanala, Ilana Perelshtein, Aharon Gedanken

Hydrogen evolution reaction (HER) in acid electrolytes has advantages for electrolysis of water due to large supply of hydrogen ions. Herein, we report the synthesis of ruthenium doped nickel hydroxide on commercial nickel foam (Ru−Ni(OH)2/NF) by using simple hydrothermal method. Due to integrated assembly and porous structure, as prepared Ru−Ni(OH)2/NF is explored as an electrocatalyst for HER in 0.5 M H2SO4 solution at room temperature. The Ru−Ni(OH)2/NF showed excellent electrocatalytic HER activity with Tafel slope of 94 mV/dec. The overpotential of Ru−Ni(OH)2/NF required to deliver 10 mAcm−2 current density was calculated to be 27 mV, which is smaller than that of commercial Pt/C/NF catalyst (33 mV). Furthermore, the Ru−Ni(OH)2/NF has shown decent stability and notable durability. The enhanced HER activity of Ru−Ni(OH)2/NF is attributed to Ru doping Ni(OH)2/NF and effective …

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Aug 2020 • New Journal of Physics

Coherent dynamics in frustrated coupled parametric oscillators

Marcello Calvanese Strinati, Igal Aharonovich, Shai Ben-Ami, Emanuele G Dalla Torre, Leon Bello, Avi Pe’er

We explore the coherent dynamics in a small network of three coupled parametric oscillators and demonstrate the effect of frustration on the persistent beating between them. Since a single-mode parametric oscillator represents an analogue of a classical Ising spin, networks of coupled parametric oscillators are considered as simulators of Ising spin models, aiming to efficiently calculate the ground state of an Ising network—a computationally hard problem. However, the coherent dynamics of coupled parametric oscillators can be considerably richer than that of Ising spins, depending on the nature of the coupling between them (energy preserving or dissipative), as was recently shown for two coupled parametric oscillators. In particular, when the energy-preserving coupling is dominant, the system displays everlasting coherent beats, transcending the Ising description. Here, we extend these findings to three …

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