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Aug 2022 • Optica 9 (3), 273-279, 2022

Quasi-static optical parametric amplification

Marc Jankowski, Nayara Jornod, Carsten Langrock, Boris Desiatov, Alireza Marandi, Marko Lončar, Martin M Fejer

We use dispersion-engineered PPLN nanowaveguides to demonstrate opti-cal parametric amplification without either temporal walk-off or group velocity dispersion. These quasi-static devices achieve large gains (> 145 dB/cm) across> 900 nanometers using picojoules of pump pulse energy.

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Aug 2022 • Scientific reports 12 (1), 1-9, 2022

Remote photonic detection of human senses using secondary speckle patterns

Zeev Kalyuzhner, Sergey Agdarov, Itai Orr, Yafim Beiderman, Aviya Bennett, Zeev Zalevsky

Neural activity research has recently gained signi cant attention due to its association with sensory information and behavior control. However, current methods of brain activity sensing require expensive equipment and physical contact with the subject.We propose a novel photonic-based method for remote detection of human senses. Physiological processes associated with hemodynamic activity due to activation of the cerebral cortex affected by different senses have been detected by remote monitoring of nano‐vibrations generated due to the transient blood ow to speci c regions of the brain. We have found that combination of defocused, self‐interference random speckle patterns with a spatiotemporal analysis using Deep Neural Network (DNN) allows associating between the activated sense and the seemingly random speckle patterns.

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Jul 2022 • Journal of Power Sources

Influence of loading, metallic surface state and surface protection in precious group metal hydrogen electrocatalyst for H2/Br2 redox-flow batteries

Kobby Saadi, Samuel S Hardisty, Zhanna Tatus-Portnoy, David Zitoun

Performance, durability, and abundance/cost of electrocatalytic materials are fundamental parameters in for large electrochemical storage solutions like redox-flow batteries (RFB). The acidic environment in Hydrogen–Bromine RFB (HBRFB), which targets tens of thousands of hours in durability, makes the challenge even more acute. Continuous effort to find the most effective and stable catalyst can promote HBRFB goal to become sustainable for high power storage systems. Herein, we explore the lower limits in catalyst loading for the two most active precious group metals (PGMs) – platinum and iridium (individually and in a bimetallic catalyst). The catalyst has been structurally characterized and lab-scale redox-flow cells have been cycled with a decreasing loading of PGM. Carbon support and polymeric coating on Pt catalyst shows a significant increase in the utilization of the catalyst. It enables low platinum …

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Jul 2022 • Journal of Non-Crystalline Solids

Evolution of surface relief gratings in As20Se80 amorphous chalcogenide films under laser illumination

Yu Kaganovskii, V Freilikher, M Rosenbluh

Variation of grating amplitudes on a surface of amorphous chalcogenide films (ACF) As20Se80 has been studied under illumination by a band-gap light with the purpose to understand mechanism of photo-induced (PI) mass transfer. After holographic recording of surface relief gratings (SRGs) of various periods Λ (from 3 to 15 µm) they were illuminated by a diode laser (λ = 660 nm) and their profile variation was analyzed using optical microscopy, atomic force microscopy, light scattering, and optical profilometry. The SRGs with Λ < 8 µm exponentially flattened with time of illumination, whereas amplitudes of the SRGs with Λ > 8 µm exponentially grew. Theoretical analysis of the kinetics of PI mass transfer shows that the SRG profile variation occurs by bulk diffusion of As and Se atoms as a result of competition between capillary forces and electrostatic forces created by redistribution of electrons and holes generated …

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Jun 2022 • arXiv preprint arXiv:2106.00423

Reentrant transitions in a mixture of small and big particles interacting via soft repulsive potential

Itay Azizi, Alexander Y Grosberg, Yitzhak Rabin

We report the first observation of temperature-controlled reentrant transition in simulations of mixtures of small and big particles interacting via soft repulsive potential in 2d. As temperature increases, the system passes from a fluid mixture, to a crystal of big particles in a fluid of small particles and back to a fluid mixture. Solidification is driven by entropy gain of small particles which overcomes the free energy cost of confining big ones. Melting results from enhanced interpenetration of particles at high temperature which reduces the entropic forces that stabilize the crystal.

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Jun 2022 • arXiv preprint arXiv:2106.00523

Flow of time during energy measurements and the resulting time-energy uncertainty relations

Ismael L Paiva, Augusto C Lobo, Eliahu Cohen

Uncertainty relations play a crucial role in quantum mechanics. A well-defined method exists for deriving such uncertainties for pairs of observables. It does not include, however, an important family of fundamental relations: the time-energy uncertainty relations. As a result, different approaches have been used for obtaining them in diversified scenarios. The one of interest here revolves around the idea of the existence or inexistence of a minimum duration for an energy measurement with a certain precision. In our study, we use the Page and Wooters timeless framework to investigate how energy measurements modify the relative "flow of time" between internal and external clocks. This provides a unified framework for discussing the topic, recovering previous results and leading to new ones. We also show that the evolution of the external clock with respect to the internal one is non-unitary.

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Jun 2022 • Bulletin of the American Physical Society

Multichannel nature of Efimov physics with ultracold 7Li atoms

Jose D'Incao, Yaakov Yudkin, Paul Julienne, Lev Khaykovich

We present our current understanding of various aspects of Efimov physics originating from the complex multichannel hyperfine structure and overlap of Feshbach resonances for 7Li atoms. This further help us to explain puzzling experimental observations with ultracold gases. We have characterized the energies of Efimov states and corresponding interference and resonance scattering phenomena associated to them as a function of an external magnetic field. Our results also indicate that Efimov states in the 7Li system can have a unique mixed hyperfine character which strongly affect their near-threshold behavior for repulsive interatomic interactions.[1] Y. Yudkin, R. Elbaz, L. Khaykovich, arXiv: 2004.02723.

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Jun 2022 • Bulletin of the American Physical Society

Multichannel nature of Efimov physics with ultracold 7Li atoms

Jose D'Incao, Yaakov Yudkin, Paul Julienne, Lev Khaykovich

We present our current understanding of various aspects of Efimov physics originating from the complex multichannel hyperfine structure and overlap of Feshbach resonances for 7Li atoms. This further help us to explain puzzling experimental observations with ultracold gases. We have characterized the energies of Efimov states and corresponding interference and resonance scattering phenomena associated to them as a function of an external magnetic field. Our results also indicate that Efimov states in the 7Li system can have a unique mixed hyperfine character which strongly affect their near-threshold behavior for repulsive interatomic interactions.[1] Y. Yudkin, R. Elbaz, L. Khaykovich, arXiv: 2004.02723.

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May 2022 • arXiv preprint arXiv:2205.01974

Restart expedites quantum walk hitting times

Ruoyu Yin, Eli Barkai

Classical first-passage times under restart are used in a wide variety of models, yet the quantum version of the problem still misses key concepts. We study the quantum first detected passage time under restart protocol using a monitored quantum walk. The restart strategy eliminates the problem of dark states, i.e. cases where the particle is not detected at all, while maintaining the ballistic propagation which is important for fast search. We find profound effects of quantum oscillations on the restart problem, namely a type of instability of the mean detection time, and optimal restart times that form staircases, with sudden drops as the rate of sampling is modified. In the absence of restart and in the Zeno limit, the detection of the walker is not possible and we examine how restart overcomes this well-known problem, showing that the optimal restart time becomes insensitive to the sampling period.

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May 2022 • Scientific Reports

Sourcing Herod the Great's calcite-alabaster bathtubs by a multi-analytic approach

Ayala Amir, Amos Frumkin, Boaz Zissu, Aren M Maeir, Gil Goobes, Amnon Albeck

May 2022 • ChemPlusChem

Promising Electrocatalytic Water and Methanol Oxidation Reaction Activity by Nickel Doped Hematite/Surface Oxidized Carbon Nanotubes Composite Structures

Bibhudatta Malik, Sumit Majumder, Roberto Lorenzi, Ilana Perelshtein, Michal Ejgenberg, Alberto Paleari, Gilbert Daniel Nessim

Tailoring the precise construction of non‐precious metals and carbon‐based heterogeneous catalysts for electrochemical oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) is crucial for energy conversion applications. Herein, this work reports the composite of Ni doped Fe2O3 (Ni−Fe2O3) with mildly oxidized multi‐walled CNT (O−CNT) as an outstanding Mott‐Schottky catalyst for OER and MOR. O−CNT acts as a co‐catalyst which effectively regulates the charge transfer in Ni−Fe2O3 and thus enhances the electrocatalytic performance. Ni−Fe2O3/O−CNT exhibits a low onset potential of 260 mV and overpotential 310 mV @ 10 mA cm−2 for oxygen evolution. Being a Mott‐Schottky catalyst, it achieves the higher flat band potential of −1.15 V with the carrier density of 0.173×1024 cm−3. Further, in presence of 1 M CH3OH, it delivers the MOR current density of 10 mA cm−2 at 1.46 V …

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May 2022 • Journal of The Electrochemical Society

Development of Electroactive and Stable Current Collectors for Aqueous Batteries

Gil Bergman, Amey Nimkar, Arka Saha, Bar Gavriel, Meital Turgeman, Fyodor Malchik, Tianju Fan, Merav Nadav Tsubery, Malachi Noked, Daniel Sharon, Netanel Shpigel

May 2022 • Carbohydrate Polymers

Non-radical synthesis of chitosan-quercetin polysaccharide: Properties, bioactivity and applications

Yevgenia Shebis, Alexander Laskavy, Anat Molad-Filossof, Hadar Arnon-Rips, Michal Natan-Warhaftig, Gila Jacobi, Elazar Fallik, Ehud Banin, Elena Poverenov

Quercetin-chitosan (QCS) polysaccharide was synthesized via non-radical reaction using L-valine-quercetin as the precursor. QCS was systematically characterized and demonstrated amphiphilic properties with self-assembling ability. In-vitro activity studies confirmed that quercetin grafting does not diminish but rather increases antimicrobial activity of the original chitosan (CS) and provided the modified polysaccharide with antioxidative properties. QCS applied as a coating on fresh-cut fruit reduced microbial spoilage and oxidative browning of coated melon and apple, respectively. Notably, QCS-based coatings prevented moisture loss, a major problem with fresh produce (2%, 12% and 18% moisture loss for the QCS-coated, CS-coated and uncoated fruit, respectively).The prepared QCS polysaccharide provides advanced bioactivity and does not involve radical reactions during its synthesis, therefore, it has …

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May 2022 • Pharmaceutics

Photothermal Therapy with HER2-Targeted Silver Nanoparticles Leading to Cancer Remission

Victoria O Shipunova, Mariia M Belova, Polina A Kotelnikova, Olga N Shilova, Aziz B Mirkasymov, Natalia V Danilova, Elena N Komedchikova, Rachela Popovtzer, Sergey M Deyev, Maxim P Nikitin

Nanoparticles exhibiting the localized surface plasmon resonance (LSPR) phenomenon are promising tools for diagnostics and cancer treatment. Among widely used metal nanoparticles, silver nanoparticles (Ag NPs) possess the strongest light scattering and surface plasmon strength. However, the therapeutic potential of Ag NPs has until now been underestimated. Here we show targeted photothermal therapy of solid tumors with 35 nm HER2-targeted Ag NPs, which were produced by the green synthesis using an aqueous extract of Lavandula angustifolia Mill. Light irradiation tests demonstrated effective hyperthermic properties of these NPs, namely heating by 10 С in 10 min. To mediate targeted cancer therapy, Ag NPs were conjugated to the scaffold polypeptide, affibody Z HER2: 342, which recognizes a clinically relevant oncomarker HER2. The conjugation was mediated by the PEG linker to obtain Ag-PEG-HER2 nanoparticles. Flow cytometry tests showed that Ag-PEG-HER2 particles successfully bind to HER2-overexpressing cells with a specificity comparable to that of full-size anti-HER2 IgGs. A confocal microscopy study showed efficient internalization of Ag-PEG-HER2 into cells in less than 2 h of incubation. Cytotoxicity assays demonstrated effective cell death upon exposure to Ag-PEG-HER2 and irradiation, caused by the production of reactive oxygen species. Xenograft tumor therapy with Ag-PEG-HER2 particles in vivo resulted in full primary tumor regression and the prevention of metastatic spread. Thus, for the first time, we have shown that HER2-directed plasmonic Ag nanoparticles are effective sensitizers for targeted …

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May 2022 • Protein Science

Allostery‐driven changes in dynamics regulate the activation of bacterial copper transcription factor

Idan Yakobov, Alysia Mandato, Lukas Hofmann, Kevin Singewald, Yulia Shenberger, Lada Gevorkyan‐Airapetov, Sunil Saxena, Sharon Ruthstein

Metalloregulators bind and respond to metal ions by regulating the transcription of metal homeostasis genes. Copper efflux regulator (CueR) is a copper‐responsive metalloregulator that is found in numerous Gram‐negative bacteria. Upon Cu(I) coordination, CueR initiates transcription by bending the bound DNA promoter regions facilitating interaction with RNA polymerase. The structure of Escherichia coli CueR in presence of DNA and metal ion has been reported using X‐ray crystallography and cryo‐EM, providing information about the mechanism of action. However, the specific role of copper in controlling this transcription mechanism remains elusive. Herein, we use room temperature electron paramagnetic resonance (EPR) experiments to follow allosterically driven dynamical changes in E. coli CueR induced by Cu(I) binding. We suggest that more than one Cu(I) ion binds per CueR monomer, leading to …

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May 2022 • Colloids and Surfaces A: Physicochemical and Engineering Aspects

Design of Silane-Based UV-absorbing Thin Coatings on Polyethylene Films

Taly Iline-Vul, Naftali Kanovsky, Daniel Yom-Tov, Merav Nadav-Tsubery, Shlomo Margel

UV-absorbing surfaces have received much attention and focus due to their relevance in a variety of research applications and industrial fields. However, these surfaces currently suffer from drawbacks such as instability due to leakage of the entrapped UV-absorbing compounds, complicated non-green synthetic processes, and/or lack of good optical properties. We propose a modified Stöber method where UV absorbing silane monomers containing the group2-hydroxy-4-(3-triethoxysilylpropoxy) diphenylketone (SiUV) in presence of the mesoporous producing surfactant cetyltrimethyl ammonium chloride (CTAC) was polymerized in an ethanol/water continuous phase under basic conditions. UV absorbing thin coatings onto polyethylene (PE) films were then spread with the former dispersion on corona-treated PE, followed by a thermal drying process. These films were highly UV absorbent and durable with …

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May 2022 • Communications Biology

Statistical parametrization of cell cytoskeleton reveals lung cancer cytoskeletal phenotype with partial EMT signature

Arkaprabha Basu, Manash K Paul, Mitchel Alioscha-Perez, Anna Grosberg, Hichem Sahli, Steven M Dubinett, Shimon Weiss

Epithelial–mesenchymal Transition (EMT) is a multi-step process that involves cytoskeletal rearrangement. Here, developing and using an image quantification tool, Statistical Parametrization of Cell Cytoskeleton (SPOCC), we have identified an intermediate EMT state with a specific cytoskeletal signature. We have been able to partition EMT into two steps:(1) initial formation of transverse arcs and dorsal stress fibers and (2) their subsequent conversion to ventral stress fibers with a concurrent alignment of fibers. Using the Orientational Order Parameter (OOP) as a figure of merit, we have been able to track EMT progression in live cells as well as characterize and quantify their cytoskeletal response to drugs. SPOCC has improved throughput and is non-destructive, making it a viable candidate for studying a broad range of biological processes. Further, owing to the increased stiffness (and by inference invasiveness …

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May 2022 • Heart Rhythm


Tomer Mann, Eli Eisenberg, Erez Levanon

BackgroundRNA editing is an inflammatory modulator with high activity in the cardiovascular system. It is mainly active in noncoding genomic areas, but also invokes changes in coding genes, mimicking a mutation and altering protein function. Although RNA editing is implicated in atherosclerosis and cardiomyopathy, its role in atriopathy and AF is unknown.Objective

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May 2022 • Optics Express

Coalescence of Anderson-localized modes at an exceptional point in 2D random media

Nicolas Bachelard, A Schumer, B Kumar, C Garay, J Arlandis, R Touzani, P Sebbah

In non-Hermitian settings, the particular position at which two eigenstates coalesce in the complex plane under a variation of a physical parameter is called an exceptional point. An open disordered system is a special class of non-Hermitian system, where the degree of scattering directly controls the confinement of the modes. Herein a non-perturbative theory is proposed which describes the evolution of modes when the permittivity distribution of a 2D open dielectric system is modified, thereby facilitating to steer individual eigenstates to such a non-Hermitian degeneracy. The method is used to predict the position of such an exceptional point between two Anderson-localized states in a disordered scattering medium. We observe that the accuracy of the prediction depends on the number of localized states accounted for. Such an exceptional point is experimentally accessible in practically relevant disordered photonic systems.

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Apr 2022 • arXiv preprint arXiv:2204.02888

Towards a controllable SQUID

Alex Khanukov, Itay Mangel, Shai Wissberg, Amit Keren, Beena Kalisky

Josephson junctions and superconducting quantum interference devices (SQUID) are important electronic elements, which are based on normal conductor sandwiched between two superconductors. These junctions are produced by evaporation techniques, and once they are embedded in an electronic circuit, their properties are fixed. Using SQUIDs as a tunable component requires the ability to generate Josephson junctions in situ in a reversible controllable manner. In this work we demonstrated how a normal (metallic) region along a line traversing a superconductor can be turned on and off externally thus potentially generating a controllable Josephson junction or a SQUID. The concept is based on a long, current-carrying excitation coil, piercing a ring shaped superconductor with nucleation points. The vector potential produced by this coil generates a circular current that destroys superconductivity along a radial line starting at the nucleation point. Unlike the destruction of superconductivity with magnetic field, the vector potential method is reversible and reproducible; full superconductivity is recovered upon removing the current from the coil and different cool-downs yield the same normal lines.

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Apr 2022 • arXiv preprint arXiv:2204.04657

Tunable Magnetic Scattering and Ferroelectric Switching at the LaAlO/EuTiO/SrCaTiO Interface

Gal Tuvia, Sapir Weitz Sobelman, Shay Sandik, Beena Kalisky, Yoram Dagan

Ferroelectric and ferromagnetic orders rarely coexist, and magnetoelectric coupling is even more scarce. A possible avenue for combining these orders is by interface design, where orders formed at the constituent materials can overlap and interact. Using a combination of magneto-transport and scanning SQUID measurements, we explore the interactions between ferroelectricity, magnetism, and the 2D electron system (2DES) formed at the novel LaAlO/EuTiO/SrCaTiO heterostructure. We find that the electrons at the interface experience magnetic scattering appearing along with a diverging Curie-Weiss-type behaviour in the EuTiO layer. The 2DES is also affected by the switchable ferroelectric polarization at the SrCaTiO bulk. While the 2DES interacts with both magnetism and ferroelectricity, we show that the presence of the conducting electrons has no effect on magnetization in the EuTiO layer. Our results provide a first step towards realizing a new multiferroic system where magnetism and ferroelectricity can interact via an intermediate conducting layer.

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