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Aug 2022 • International Journal of Hydrogen Energy

Adsorption of bromine complexing agents on platinum electrocatalysts and prevention through polydopamine coatings

Samuel S Hardisty, Nagaprasad Reddy Samala, Ilya Grinberg, David Zitoun

Bromine complexing agents (BCAs) are seen as a promising route to mitigate the potential health and environmental risks of the bromine-based redox-flow batteries, like the hydrogen bromine redox flow battery (H2–Br2 RFB). The most studied BCAs are based on the pyridinium anion, which may adsorb and inhibit the Pt catalyst required in the H2–Br2 RFB system for the hydrogen reactions. Herein the effect of two BCAs (ethyl-pyridinium bromide and hexyl-pyridinium bromide) on a Pt electrocatalyst are studied, along with a potential methodology to prevent adsorption of the BCA through a polydopamine (PDA) coating. The results show that the pyridinium anion is adsorbed on Pt throughout a large potential range (−0.02 to 1.0 V), reducing the availability of the surface for the adsorption of other species. The PDA coating prevented this adsorption, but itself experiences adsorption of the BCA leading to some …

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Aug 2022 • Proceedings of the National Academy of Sciences

The Role of Spin-Flip Collisions in a Dark-Exciton Condensate

Subhradeep Misra, Michael Stern, Vladimir Umansky, Israel Bar-Joseph

We show that a Bose–Einstein condensate consisting of dark excitons forms in GaAs coupled quantum wells at low temperatures. We find that the condensate extends over hundreds of micrometers, well beyond the optical excitation region, and is limited only by the boundaries of the mesa. We show that the condensate density is determined by spin-flipping collisions among the excitons, which convert dark excitons into bright ones. The suppression of this process at low temperature yields a density buildup, manifested as a temperature-dependent blueshift of the exciton emission line. Measurements under an in-plane magnetic field allow us to preferentially modify the bright exciton density and determine their role in the system dynamics. We find that their interaction with the condensate leads to its depletion. We present a simple rate-equations model, which well reproduces the observed temperature, power, and …

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Aug 2022 • Optical Fiber Sensors, Tu1. 4, 2022

Brillouin optical time-domain distributed analysis of cladding modes in a coated fiber

Elad Zehavi, Alon Bernstein, Gil Bashan, Yosef London, Hilel Hagai Diamandi, Kavita Sharma, Mirit Hen, A Zadok

Brillouin optical time domain analysis of coupling to cladding modes of standard, coated fiber is demonstrated. Uncertainty in local changes of effective indices is below 10-6 RIU. Local effect of acetone on coating is identified.

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Aug 2022 • Physical Review B

Nonadiabatically driven open quantum systems under out-of-equilibrium conditions: Effect of electron-phonon interaction

Jakob Bätge, Amikam Levy, Wenjie Dou, Michael Thoss

In this paper we explore the effects of nonadiabatic external driving on the dynamics of an electronic system coupled to two electronic leads and to a phonon mode, with and without damping. In the limit of slow driving, we establish nonadiabatic corrections to thermodynamic and transport quantities. In particular, we study the first-order correction to the work done by the driving, the charge current, and the vibrational excitation using a perturbative expansion. We then compare the results to the numerically exact hierarchical equations of motion (HEOM) approach. Furthermore, the HEOM analysis spans both the weak and strong system-bath coupling regime and the slow-and fast-driving limits. We show that the electronic friction and the nonadiabatic corrections to the charge current provide a clear indicator for the Franck-Condon effect and for nonresonant tunneling processes. We also discuss the validity of the …

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Aug 2022 • Advanced Functional Materials

The Saga of Water and Halide Perovskites: Evidence of Water in Methylammonium Lead Tri‐Iodide

Naga Prathibha Jasti, Gennady E Shter, Yishay Feldman, Davide Raffaele Ceratti, Adi Kama, Isaac Buchine, Gideon S Grader, David Cahen

The environment humidity effects on performance of halide perovskites (HaPs), especially MAPbI3, are known. Nevertheless, it is hard to find direct experimental evidence of H2O in the bulk materials at the levels lower than that of Monohydrate (MAPbI3.H2O). Here, for the first time, direct experimental evidence of water being released from bulk (µm‐s deep) of MAPbI3 single crystal is reported. The thermogravimetric analysis coupled with mass spectrometry (TGA‐MS) of evolved gases is used to detect the MS signal of H2O from the penetrable depth and correlate it with the TGA mass loss due to H2O leaving the material. These measurements yield an estimate of the average H2O content of 1 H2O molecule per three MAPbI3 formula units (MAPbI3.0.33H2O). Under the relatively low temperature conditions no other evolved gases that can correspond to MAPbI3 decomposition products, are observed in the MS. In …

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Aug 2022 • Catalysts 12 (8), 909, 2022

Levulinic Acid Is a Key Strategic Chemical from Biomass

Amudhavalli Victor, Pankaj Sharma, Indra Neel Pulidindi, Aharon Gedanken

Levulinic acid (LA) is one of the top twelve chemicals listed by the US Department of Energy that can be derived from biomass. It serves as a building block and platform chemical for producing a variety of chemicals, fuels and materials which are currently produced in fossil based refineries. LA is a key strategic chemical, as fuel grade chemicals and plastic substitutes can be produced by its catalytic conversion. LA derivatisation to various product streams, such as alkyl levulinates via esterification, γ-valerolactone via hydrogenation and N-substituted pyrrolidones via reductive amination and many other transformations of commercial utility are possible owing to the two oxygen functionalities, namely, carbonyl and carboxyl groups, present within the same substrate. Various biomass feedstock, such as agricultural wastes, marine macroalgae, and fresh water microalgae were successfully converted to LA in high yields. Finding a substitute to mineral acid catalysts for the conversion of biomass to LA is a challenge. The use of an ultrasound technique facilitated the production of promising nano-solid acid catalysts including Ga salt of molybophosphoric acid and Ga deposited mordenite zeolite, with optimum amounts of Lewis and Bronsted acidities needed for the conversion of glucose to LA in high yields, being 56 and 59.9 wt.% respectively. Microwave irradiation technology was successfully utilized for the accelerated production of LA (53 wt.%) from glucose in a short duration of 6 min, making use of the unique synergistic catalytic activity of ZnBr2 and HCl.

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Aug 2022 • Journal of Chemical Theory and Computation

Solvent Dependent Nuclear Magnetic Resonance Molecular Parameters Based on a Polarization Consistent Screened Range Separated Hybrid Density Functional Theory Framework

Khadiza Begam, Lilian Cohen, Gil Goobes, Barry D Dunietz

Nuclear magnetic resonance (NMR) properties of solvated molecules are significantly affected by the solvent. We, therefore, employ a polarization consistent framework that efficiently addresses the solvent polarizing environment effects. Toward this goal a dielectric screened range separated hybrid (SRSH) functional is invoked with a polarizable continuum model (PCM) to properly represent the orbital gap in the condensed phase. We build on the success of range separated hybrid (RSH) functionals to address the erroneous tendency of traditional density functional theory (DFT) to collapse the orbital gap. Recently, the impact of RSH that properly opens up the orbital gap in gas-phase calculations on NMR properties has been assessed. Here, we report the use of SRSH-PCM that produces properly solute orbital gaps in calculating isotropic nuclear magnetic shielding and chemical shift parameters of molecular …

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Aug 2022 • arXiv preprint arXiv:2208.10262

Controls that expedite scale-invariant transport in disordered systems

Marc Höll, Alon Nissan, Brian Berkowitz, Eli Barkai

Transport in disordered media, such as those involving charge carriers in amorphous semiconductors, or contaminants in hydrogeological systems, are often described by time scale-free processes. We study the statistical properties of the first passage time of biased processes in different models, and employ the big jump principle that shows the dominance of the maximum trapping time on the first passage time. Inspired by the restart paradigm, we demonstrate that the removal of this maximum significantly expedites transport. As the disorder increases, the system enters a phase where the removal shows a dramatic effect. Our results show how we may speed up transport in strongly disordered systems exploiting scale invariance.

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Aug 2022 • Optical Fiber Sensors, Tu1. 5, 2022

Direct Spatially Distributed Analysis of Forward Brillouin Scattering in Polarization Maintaining Fibers

Kavita Sharma, Elad Zehavi, Hilel Hagai Diamandi, Gil Bashan, Yosef London, Avi Zadok

Direct distributed analysis of forward Brillouin scattering is demonstrated for the first time. Intermodal scattering in a polarization maintaining fiber is mapped via a counterpropagating probe. Measurements distinguish between air and water outside coated fiber.

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Aug 2022 • Current Opinion in Electrochemistry, 101107, 2022

Electrical double layer in nano-pores of carbon electrodes: Beyond CDI; sensing and maximizing energy extraction from salinity gradients

Eran Avraham, Barak Shapira, Izaak Cohen, Doron Aurbach

The important phenomenon of electrical double layer (EDL) is often described by mathematical relations between surface charges, variation of electrostatic potentials with distance and distribution of ions across the interface between charged surfaces (or particles) and electrolyte solutions. A major advance was made in the last decade in understanding complex EDL relationships with an emphasis on nano-porous carbonaceous materials. These understandings were usually exploited for the interpretation of electro-sorption phenomena connected to capacitive deionization (CDI) processes. The aim of this short paper is to demonstrate, based on previous studies, how models of EDL in nano-porous carbons can be the basis for modification of carbonaceous materials for other applications, like sensors and energy extraction from salinity gradients.

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Aug 2022 • arXiv preprint arXiv:2108.13047

Measurement-induced quantum walks

A Didi, E Barkai

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.

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Aug 2022 • ACS Applied Bio Materials

Cuprous Oxide Nanoparticles Decorated Fabric Materials with Anti-biofilm Properties

Akanksha Gupta, Moorthy Maruthapandi, Poushali Das, Arumugam Saravanan, Gila Jacobi, Michal Natan, Ehud Banin, John HT Luong, Aharon Gedanken

Considering the global spread of bacterial infections, the development of anti-biofilm surfaces with high antimicrobial activities is highly desired. This work unraveled a simple, sonochemical method for coating Cu2O nanoparticles (NPs) on three different flexible substrates: polyester (PE), nylon 2 (N2), and polyethylene (PEL). The introduction of Cu2O NPs on these substrates enhanced their surface hydrophobicity, induced ROS generation, and completely inhibited the growth of sensitive (Escherichia coli and Staphyloccocus aureus) and drug-resistant (MDR E. coli and MRSA) planktonic and biofilm. The experimental results confirmed that Cu2O-PE exhibited complete biofilm mass reduction ability for all four strains, whereas Cu2O-N2 showed more than 99% biomass inhibition against both drug-resistant and sensitive pathogens in 6 h. Moreover, Cu2O-PEL also indicated a 99.95, 97.73, 98.00, and 99.20 …

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Aug 2022 • 2022 47th International Conference on Infrared, Millimeter and Terahertz …, 2022

The Response of Split-Well Direct-Phonon THz Quantum-Cascade Laser Structures to Changes in Doping

N Lander Gower, S Piperno, A Albo

We have studied the effect of doping on the temperature performance of a split-well (SW) direct-phonon (DP) terahertz (THz) quantum-cascade laser (QCL) scheme supporting a clean three-level system. We expected to obtain a similar improvement in the temperature performance to that observed in resonant-phonon (RP) schemes after increasing the carrier concentration from To our surprise, in the devices we checked, the results show the contrary. However, we observed a significant increase in gain broadening and a reduction in the dephasing time as the doping and temperature increased. We attribute these effects to enhanced ionized-impurity scattering (IIS). The observation and study of effects related to dephasing included in our experimental work have previously only been possible via simulation.

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Aug 2022 • Optical Fiber Sensors, Th4. 67, 2022

Forward Brillouin Point Sensor in a Multi-Core Fiber

Keren Shemer, Gil Bashan, Elad Zehavi, Hilel Hagai Diamandi, Alon Bernstein, Kavita Sharma, Yosef London, David Barrera, Salvador Sales, Avi Zadok

Forward Brillouin point sensing is demonstrated in a multi-core fiber. Acoustic waves are stimulated by light in one core and monitored using a grating in another. Measurements distinguish between ethanol and water outside the cladding.

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Aug 2022 • Catalysts 12 (8), 909, 2022

Levulinic Acid Is a Key Strategic Chemical from Biomass

Amudhavalli Victor, Pankaj Sharma, Indra Neel Pulidindi, Aharon Gedanken

Levulinic acid (LA) is one of the top twelve chemicals listed by the US Department of Energy that can be derived from biomass. It serves as a building block and platform chemical for producing a variety of chemicals, fuels and materials which are currently produced in fossil based refineries. LA is a key strategic chemical, as fuel grade chemicals and plastic substitutes can be produced by its catalytic conversion. LA derivatisation to various product streams, such as alkyl levulinates via esterification, γ-valerolactone via hydrogenation and N-substituted pyrrolidones via reductive amination and many other transformations of commercial utility are possible owing to the two oxygen functionalities, namely, carbonyl and carboxyl groups, present within the same substrate. Various biomass feedstock, such as agricultural wastes, marine macroalgae, and fresh water microalgae were successfully converted to LA in high yields. Finding a substitute to mineral acid catalysts for the conversion of biomass to LA is a challenge. The use of an ultrasound technique facilitated the production of promising nano-solid acid catalysts including Ga salt of molybophosphoric acid and Ga deposited mordenite zeolite, with optimum amounts of Lewis and Bronsted acidities needed for the conversion of glucose to LA in high yields, being 56 and 59.9 wt.% respectively. Microwave irradiation technology was successfully utilized for the accelerated production of LA (53 wt.%) from glucose in a short duration of 6 min, making use of the unique synergistic catalytic activity of ZnBr 2 and HCl. View Full-Text

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Aug 2022 • IEEE Photonics Journal

Measurement of the Second-Order Polarizability of Silver Nanoparticles With Reference-Free Hyper-Rayleigh Scattering for Entangled Photon Pair Interaction

Ariel Ashkenazy, Racheli Ron, Tchiya Zar, Hannah Aharon, Adi Salomon, Dror Fixler, Eliahu Cohen

Two-photon interactions of entangled-photon pairs with metallic nanoparticles (NPs) can be enhanced by localized surface-plasmon resonance. Recently, we have described how the properties of this quantum light-matter interaction can be deduced from classical second-harmonic generation measurements performed using a reference-free hyper-Rayleigh scattering method. Herein, we report the results of such classical-light characterization measurements. We obtain a large hyperpolarizability for the NPs, present the dependence of the hyperpolarizability on the NPs' spectral features, and show a dipolar emission pattern for the second-harmonic signal. Our results can be used to optimize entangled-photon pair interactions with metallic NPs to enable first ever detection of this process. Moreover, these results suggest that NPs may be used as source for ultra-broadband entangled-photon pairs through nonphase …

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Aug 2022 • Optical Fiber Sensors, Tu1. 4, 2022

Brillouin Optical Time-Domain Distributed Analysis of Cladding Modes in a Coated Fiber

Elad Zehavi, Alon Bernstein, Gil Bashan, Yosef London, Hilel Hagai Diamandi, Kavita Sharma, Mirit Hen, A Zadok

Brillouin optical time domain analysis of coupling to cladding modes of standard, coated fiber is demonstrated. Uncertainty in local changes of effective indices is below 10-6 RIU. Local effect of acetone on coating is identified.

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Aug 2022 • Viruses

Lytic Reactivation of the Kaposi’s sarcoma-associated herpesvirus (KSHV) is Accompanied by Major Nucleolar Alterations

Nofar Atari, K Shanmugha Rajan, Vaibhav Chikne, Smadar Cohen-Chalamish, Tirza Doniger, Odelia Orbaum, Avi Jacob, Inna Kalt, Shulamit Michaeli, Ronit Sarid

The nucleolus is a subnuclear compartment whose primary function is the biogenesis of ribosomal subunits. Certain viral infections affect the morphology and composition of the nucleolar compartment and influence ribosomal RNA (rRNA) transcription and maturation. However, no description of nucleolar morphology and function during infection with Kaposi’s sarcoma-associated herpesvirus (KSHV) is available to date. Using immunofluorescence microscopy, we documented extensive destruction of the nuclear and nucleolar architecture during the lytic reactivation of KSHV. This was manifested by the redistribution of key nucleolar proteins, including the rRNA transcription factor UBF. Distinct delocalization patterns were evident; certain nucleolar proteins remained together whereas others dissociated, implying that nucleolar proteins undergo nonrandom programmed dispersion. Significantly, the redistribution of UBF was dependent on viral DNA replication or late viral gene expression. No significant changes in pre-rRNA levels and no accumulation of pre-rRNA intermediates were found by RT-qPCR and Northern blot analysis. Furthermore, fluorescent in situ hybridization (FISH), combined with immunofluorescence, revealed an overlap between Fibrillarin and internal transcribed spacer 1 (ITS1), which represents the primary product of the pre-rRNA, suggesting that the processing of rRNA proceeds during lytic reactivation. Finally, small changes in the levels of pseudouridylation (Ψ) and 2′-O-methylation (Nm) were documented across the rRNA; however, none were localized to the functional domain. Taken together, our results suggest that …

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Aug 2022 • Current Opinion in Electrochemistry, 101107, 2022

Electrical Double Layer in Nano-Pores of Carbon Electrodes: Beyond CDI; Sensing and Maximizing Energy Extraction from Salinity Gradients

Eran Avraham, Barak Shapira, Izaak Cohen, Doron Aurbach

The important phenomenon of electrical double layer (EDL) is often described by mathematical relations between surface charges, variation of electrostatic potentials with distance and distribution of ions across the interface between charged surfaces (or particles) and electrolyte solutions. A major advance was made in the last decade in understanding complex EDL relationships with an emphasis on nano-porous carbonaceous materials. These understandings were usually exploited for the interpretation of electro-sorption phenomena connected to capacitive deionization (CDI) processes. The aim of this short paper is to demonstrate, based on previous studies, how models of EDL in nano-porous carbons can be the basis for modification of carbonaceous materials for other applications, like sensors and energy extraction from salinity gradients.

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Aug 2022 • SPring-8/SACLA Research Report

Higher-Order X-ray-Optical Wave Mixing

Priyanka Chakraborti, Ozgur Culfa, Matthias Fuchs, Johann Haber, David Reis, Sharon Shwartz, Kenji Tamasaku, Samuel Teitelbaum

The goal of the experiment was to investigate higher-order X-ray-optical sum-frequency generation (XSFG) as a means to study the dynamics of linear and nonlinear optically-induced local polarization effects in solids with Angstrom resolution. XSFG can be used as time-resolved atomic-scale probe of the dynamics of optically induced charge densities. The ability to optically control carrier dynamics in samples at the microscopic scale has the potential to become the basis of ultrafast optical switching of currents and future petahertz optoelectronic devices.

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Aug 2022 • IEEE Photonics Journal

Measurement of the Second-Order Polarizability of Silver Nanoparticles With Reference-Free Hyper-Rayleigh Scattering for Entangled Photon Pair Interaction

Ariel Ashkenazy, Racheli Ron, Tchiya Zar, Hannah Aharon, Adi Salomon, Dror Fixler, Eliahu Cohen

Two-photon interactions of entangled-photon pairs with metallic nanoparticles (NPs) can be enhanced by localized surface-plasmon resonance. Recently, we have described how the properties of this quantum light-matter interaction can be deduced from classical second-harmonic generation measurements performed using a reference-free hyper-Rayleigh scattering method. Herein, we report the results of such classical-light characterization measurements. We obtain a large hyperpolarizability for the NPs, present the dependence of the hyperpolarizability on the NPs' spectral features, and show a dipolar emission pattern for the second-harmonic signal. Our results can be used to optimize entangled-photon pair interactions with metallic NPs to enable first ever detection of this process. Moreover, these results suggest that NPs may be used as source for ultra-broadband entangled-photon pairs through nonphase …

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