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Apr 2021 • Advanced Functional Materials

Porphyrin aerogel catalysts for oxygen reduction reaction in anion‐exchange membrane fuel cells

Noam Zion, John C Douglin, David A Cullen, Piotr Zelenay, Dario R Dekel, Lior Elbaz

Platinum group metal (PGM)‐free catalysts for oxygen reduction reaction have shown high oxygen reduction reaction activity in alkaline media. In order to further increase the power density of anion‐exchange membrane fuel cells (AEMFCs), PGM‐free catalysts need to have a high site density to reach high current densities. Herein, synthesis, characterization, and utilization of heat‐treated iron porphyrin aerogels are reported as cathode catalysts in AEMFCs. The heat treatment effect is thoroughly studied and characterized using several techniques, and the best performing aerogel is studied in AEMFC, showing excellent performance, reaching a peak power density of 580 mW cm−2 and a limiting current density of as high as 2.0 A cm−2, which can be considered the state‐of‐the‐art for PGM‐free based AEMFCs.

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Apr 2021 • arXiv preprint arXiv:2104.10524

Observation of strong coupling between an inverse bowtie nano-antenna and a single j-aggregate

Adam Weissman, Maxim Shukharev, Adi Salomon

We demonstrate strong coupling between a single J-aggregate and an inverse bowtie plasmonic structure, when the J-aggregate is located at a specific axial distance from the metallic surface. Three hybrid modes are clearly observed, witnessing a strong interaction, with a Rabi splitting of up to 290 meV, the precise value of which significantly depends on the orientation of the J-aggregate with respect to the symmetry axis of the plasmonic structure. We repeated our experiments with a set of triangular hole arrays, showing consistent formation of three or more hybrid modes, in good agreement with numerical simulations.

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Apr 2021 • Nano-Structures & Nano-Objects

Biocompatible N-doped carbon dots for the eradication of methicillin-resistant S. aureus (MRSA) and sensitive analysis for europium (III)

Moorthy Maruthapandi, Poushali Das, Arumugam Saravanan, Michal Natan, Ehud Banin, Sriram Kannan, Shulamit Michaeli, John HT Luong, Aharon Gedanken

Plant leaves have more attracted in the preparation of carbon dots (CDs) owing to natural phytochemicals. Herein, we performed a one-pot hydrothermal process for the synthesis of Nitrogen doped CDs (N@ CDs) from glossy heart-shaped Piper betel leaves (P. betel). The prepared N@ CDs were effectively applied for the eradication of E. coli, S. aureus, and methicillin-resistant S. aureus (MRSA). The N@ CDs were also used as a sensor for lanthanides detection with notable selectivity for Eu 3+. The results revealed that the water-soluble N@ CDs displayed narrow size particle distribution with a mean diameter of 2.6 nm. The bright fluorescence was estimated to be at λ ex: 350 with λ em: 430 nm. The functional groups on N@ CDs were confirmed by FTIR and XPS. The antimicrobial effect of N@ CDs was concentration-dependent and effectively against E. coli and S. aureus at 1000 μ g/mL. The antibacterial …

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Apr 2021 • Nature Photonics

A wavelength-scale black phosphorus spectrometer

Shaofan Yuan, Doron Naveh, Kenji Watanabe, Takashi Taniguchi, Fengnian Xia

On-chip spectrometers with compact footprints are being extensively investigated owing to their promising future in critical applications such as sensing, surveillance and spectral imaging. Most existing miniaturized spectrometers use large arrays of photodetection elements to capture different spectral components of incident light, from which its spectrum is reconstructed. Here, we demonstrate a mid-infrared spectrometer in the 2–9 µm spectral range, utilizing a single tunable black phosphorus photodetector with an active area footprint of only 9× 16 µm 2, along with a unique spectral learning procedure. Such a single-detector spectrometer has a compact size at the scale of the operational wavelength. Leveraging the wavelength and bias-dependent responsivity matrix learned from the spectra of a tunable blackbody source, we reconstruct unknown spectra from their corresponding photoresponse vectors. Enabled …

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Apr 2021

Supplementary Info: Multi-parameter photon-by-photon hidden Markov modeling

Paul David Harris, Shimon Weiss, Eitan Lerner, Edmond J Safra Campus

All code and raw data (in the form of photon-HDF5 files) is available for download here:(https://zenodo. org/record/4671393 [1]). Data must be extracted from the FRETbursts [2] data structure, and cast such that the H2MM_C package [3] can process it. In the H2MM algorithm, photons are identified by an unsigned integer index, and an unsigned integer arrival time. A burst consists of two arrays of equal length, one for the indexes, and the other for the arrival times (in the form of one dimensional numpy arrays). The python function accepts as input an initiating H2MM state model (implemented as a python extension type in the H2MM_C package [3]), a python list of the arrays of the photon indexes, and a separate python list of the arrays of the photon arrival times. FRETbursts identifies streams according to the following convention: the excitation period∗ harripd@ gmail. com† eitan. lerner@ mail. huji. ac. il

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Apr 2021 • Molecular cell

Deciphering the principles of the RNA editing code via large-scale systematic probing

Anna Uzonyi, Ronit Nir, Ofir Shliefer, Noam Stern-Ginossar, Yaron Antebi, Yonatan Stelzer, Erez Y Levanon, Schraga Schwartz

Adenosine-to-inosine editing is catalyzed by ADAR1 at thousands of sites transcriptome-wide. Despite intense interest in ADAR1 from physiological, bioengineering, and therapeutic perspectives, the rules of ADAR1 substrate selection are poorly understood. Here, we used large-scale systematic probing of ∼2,000 synthetic constructs to explore the structure and sequence context determining editability. We uncover two structural layers determining the formation and propagation of A-to-I editing, independent of sequence. First, editing is robustly induced at fixed intervals of 35 bp upstream and 30 bp downstream of structural disruptions. Second, editing is symmetrically introduced on opposite sites on a double-stranded structure. Our findings suggest a recursive model for RNA editing, whereby the structural alteration induced by the editing at one site iteratively gives rise to the formation of an additional editing site …

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Apr 2021 • Polymers for Advanced Technologies

Layer by layer controlled synthesis at room temperature of tri‐modal (MRI, fluorescence and CT) core/shell superparamagnetic IO/human serum albumin nanoparticles for diagnostic …

Sayan Ganguly, Igor Grinberg, Shlomo Margel

Magnetic nanoparticles (NPs) are drawing attention since few decades because of its tunable properties. It is well known that the degradation of plasma proteins like albumin in cancer cells is significantly faster than in normal cells. Hereby, we combined the advantages of human serum albumin (HSA) and iron oxide NPs (IO NPs) to prepare mono‐, bi‐ and tri‐modal IO/HSA core‐shell NPs for diagnostic applications, to promote the smooth and precise assessment of signals obtained from diagnostic machines. HSA is well known as a physiological carrier for many biomaterials (e.g., fatty acids, metal ions, amino acids, peptides, drugs, etc.). Mono‐modal magnetic resonance imaging (MRI) IO NPs were prepared via nucleation at room temperature of IO layers onto IO‐HSA nuclei. Mono‐modal IO/HSA NPs were produced by heating the IO NPs aqueous HSA dispersion to 80°C, followed by HSA precipitation via …

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Mar 2021 • Optical and Quantum Sensing and Precision Metrology 11700, 185-197, 2021

Quantum x-ray imaging for medical and industrial applications

Brian D Yanoff, Sharon Shwartz, Eliahu Cohen, Vasil Bogdan Neculaes, Uwe Wiedmann, Jonathan Owens, Loucas Tsakalakos

We provide an introductory overview of medical and industrial x-ray imaging applications and requirements for readers whose primary background is in quantum imaging. We discuss some opportunities for quantum X-ray imaging and related techniques such as ghost imaging to provide meaningful benefits in imaging and explain some of the key challenges that remain before practical applications can reach end users.

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Mar 2021 • Bulletin of the American Physical Society

Super-Poissonian behavior of the energy specrum in the non-ergodic extended regime

Richard Berkovits

R44. 00010: Super-Poissonian behavior of the energy specrum in the non-ergodic extended regime

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Mar 2021 • Dynamics and Fluctuations in Biomedical Photonics XVIII 11641, 30-33, 2021

Assessment of tissue perfusion in the lower limbs using laser speckle analysis

Mark Golberg, Ran Califa, Sagi Polani, Orit Goldstein, Aviram Zailer, Meir Niska, Zeev Zalevsky

Diabetic foot is a well-known problem among patients suffering from peripheral arterial diseases (PAD). An optical sensor was built for a contactless measurement of the anatomical site, composing of a diode-laser and a high-speed camera. The laser illuminates the inspected tissue and the back reflected light forms time changing speckle patterns. We used second order autocorrelation function (ACF) decay time as merit for blood flow estimation. Clinical study with 15 subjects was conducted. An occlusion test was introduced to provoke a statistical parameter to distinguish between low perfused and a healthy foot.

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Mar 2021 • Journal of Neural Engineering

Cortical responses to prosthetic retinal stimulation are significantly affected by the light-adaptive state of the surrounding normal retina

Tamar Arens-Arad, Rivkah Lender, Nairouz Farah, Yossi Mandel

Objective. Restoration of central vision loss in patients with age-related macular degeneration (AMD) by implanting a retinal prosthesis is associated with an intriguing situation wherein the central prosthetic vision co-exists with natural normal vision. Of major interest are the interactions between the prosthetic and natural vision. Here we studied the effect of the light-adaptive state of the normal retina on the electrical visual evoked potentials (VEPs) arising from the retinal prosthesis. Approach. We recorded electrical VEP elicited by prosthetic retinal stimulation in wild-type rats implanted with a 1 mm photovoltaic subretinal array. Cortical responses were recorded following overnight dark adaption and compared to those recorded following bleaching of the retina by light (520 nm) at various intensities and durations. Main results. Compared to dark-adapted responses, bleaching induced a 2-fold decrease in the …

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Mar 2021 • Physical Chemistry Chemical Physics

Comment on “Bi-layering at ionic liquid surfaces: a sum – frequency generation vibrational spectroscopy – and molecular dynamics simulation-based study” by T. Iwahashi, T …

Moshe Deutsch, Olaf M. Magnussen, Julia Haddad, Diego Pontoni, Bridget M. Murphy, Benjamin M. Ocko.

Mar 2021 • Bulletin of the American Physical Society

Complex two-mode quadratures-a generalized formalism for continuous-variable quantum optics

Leon Bello, Yoad Michael, Michael Rosenbluh, Eliahu Cohen, Avi Pe'er

S31. 00013: Complex two-mode quadratures-a generalized formalism for continuous-variable quantum optics

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Mar 2021 • Bulletin of the American Physical Society

Imaging filamentary current flow near the metal-insulator transition in an oxide interface

Eylon Persky, Naor Vardi, Ana Monteiro, Thierry van Thiel, Hyeok Yoon, Yan-Wu Xie, Benoit Fauque, Andrea Caviglia, Harold Hwang, Kamran Behnia, Beena Kalisky

S44. 00005: Imaging filamentary current flow near the metal-insulator transition in an oxide interface*

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Mar 2021 • Journal of Colloid and Interface Science

Electrically conductive cotton fabric coatings developed by silica sol-gel precursors doped with surfactant-aided dispersion of vertically aligned carbon nanotubes fillers in …

Valentina Trovato, Eti Teblum, Yulia Kostikov, Andrea Pedrana, Valerio Re, Gilbert Daniel Nessim, Giuseppe Rosace

HypothesisFrom the end of the twentieth century, the growing interest in a new generation of wearable electronics with attractive application for military, medical and smart textiles fields has led to a wide investigation of chemical finishes for the production of electronic textiles (e-textiles).ExperimentsHerein, a novel method to turn insulating cotton fabrics in electrically conductive by the deposition of three-dimensional hierarchical vertically aligned carbon nanotubes (VACNT) is proposed. Two VACNT samples with different length were synthesized and then dispersed in 4-dodecylbenzenesulfonic acid combined with silica-based sol-gel precursors. The dispersed VACNT were separately compounded with a polyurethane thickener to obtain homogeneous spreadable pastes, finally coated onto cotton surfaces by the “knife-over-roll” technique.FindingsShorter VACNT-based composite showed the best electrical …

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Mar 2021 • ChemElectroChem 8 (5), 798-811, 2021

Tunnel‐Type Sodium Manganese Oxide Cathodes for Sodium‐Ion Batteries

Munseok S Chae, Yuval Elias, Doron Aurbach

Tunnel‐type sodium manganese oxide is attracting attention as a cheap and earth‐abundant cathode material for sodium‐ion batteries, offering more stable cycling performance than other layered materials due to its special structural ordering. Developments and applications in aqueous and nonaqueous electrolyte solutions are reviewed, and problems and possible solutions are discussed in detail.

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Mar 2021 • Bulletin of the American Physical Society

Mutually Reinforced Polymer-Graphene Bilayer Membrane for Energy-Efficient Acoustic Transduction

Guoliang Liu, Gabriel Zeltzer, Doron Naveh, Gavriel Speyer, Assad Ullah Khan, Zacary Croft

We present a lightweight, flexible, transparent, and conductive bilayer composite of polyimide and single-layer graphene suspended on the centimeter scale with an unprecedentedly high aspect-ratio of 1e5. The coupling of the two components leads to mutual reinforcement and creates an ultra-strong membrane that supports 30,000 times its own weight. Upon electromechanical actuation, the membrane pushes a massive amount of air and generates high-quality acoustic sound. The energy efficiency is~ 10-100 times better than state-of-the-art electrodynamic speakers. The bilayer membrane’s combined properties of electrical conductivity, mechanical strength, optical transparency, thermal stability, and chemical resistance will promote applications in electronics, mechanics, and optics.

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Mar 2021 • Frontiers in behavioral neuroscience

Transcriptome analysis of NPFR neurons reveals a connection between proteome diversity and social behavior

Julia Ryvkin, Assa Bentzur, Anat Shmueli, Miriam Tannenbaum, Omri Shallom, Shiran Dokarker, Jennifer IC Benichou, Mali Levi, Galit Shohat-Ophir

Social behaviors are mediated by the activity of highly complex neuronal networks, the function of which is shaped by their transcriptomic and proteomic content. Contemporary advances in neurogenetics, genomics, and tools for automated behavior analysis make it possible to functionally connect the transcriptome profile of candidate neurons to their role in regulating behavior. In this study we used Drosophila melanogaster to explore the molecular signature of neurons expressing receptor for neuropeptide F (NPF), the fly homologue of neuropeptide Y (NPY). By comparing the transcription profile of NPFR neurons to those of nine other populations of neurons, we discovered that NPFR neurons exhibit a unique transcriptome, enriched with receptors for various neuropeptides and neuromodulators, as well as with genes known to regulate behavioral processes, such as learning and memory. By manipulating RNA editing and protein ubiquitination programs specifically in NPFR neurons, we demonstrate that the proper expression of their unique transcriptome and proteome is required to suppress male courtship and certain features of social group interaction. Our results highlight the importance of transcriptome and proteome diversity in the regulation of complex behaviors and pave the path for future dissection of the spatiotemporal regulation of genes within highly complex tissues, such as the brain.

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Mar 2021 • Nature communications 12 (1), 6162, 2021

Aging power spectrum of membrane protein transport and other subordinated random walks

Zachary Fox, Eli Barkai, Diego Krapf

Single-particle tracking offers detailed information about the motion of molecules in complex environments such as those encountered in live cells, but the interpretation of experimental data is challenging. One of the most powerful tools in the characterization of random processes is the power spectral density. However, because anomalous diffusion processes in complex systems are usually not stationary, the traditional Wiener-Khinchin theorem for the analysis of power spectral densities is invalid. Here, we employ a recently developed tool named aging Wiener-Khinchin theorem to derive the power spectral density of fractional Brownian motion coexisting with a scalefree continuous time random walk, the two most typical anomalous diffusion processes. Using this analysis, we characterize the motion of voltage-gated sodium channels on the surface of hippocampal neurons. Our results show aging where the power spectral density can either increase or decrease with observation time depending on the specific parameters of both underlying processes.

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Mar 2021 • Crystals

Improving compactness of 3d metallic microstructures printed by laser-induced forward transfer

Niv Gorodesky, Sharona Sedghani-Cohen, Ofer Fogel, Amir Silber, Maria Tkachev, Zvi Kotler, Zeev Zalevsky

Laser-induced forward transfer (LIFT) has been shown to be a useful technique for the manufacturing of micron-scale metal structures. LIFT is a high-resolution, non-contact digital printing method that can support the fabrication of complex shapes and multi-material structures in a single step under ambient conditions. However, LIFT printed metal structures often suffer from inferior mechanical, electrical, and thermal properties when compared to their bulk metal counterparts, and often are prone to enhanced chemical corrosion. This is due mostly to their non-compact structures, which have voids and inter-droplet delamination. In this paper, a theoretical framework together with experimental results of achievable compactness limits is presented for a variety of metals. It is demonstrated that compactness limits depend on material properties and jetting conditions. It is also shown how a specific choice of materials can yield compact structures, for example, when special alloys are chosen along with a suitable donor construct. The example of printed amorphous ZrPd is detailed. This study contributes to a better understanding of the limits of implementing LIFT for the fabrication of metal structures, and how to possibly overcome some of these limitations. View Full-Text

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Mar 2021 • ChemElectroChem 8 (5), 798-811, 2021

Tunnel‐Type Sodium Manganese Oxide Cathodes for Sodium‐Ion Batteries

Munseok S Chae, Yuval Elias, Doron Aurbach

Tunnel‐type sodium manganese oxide is attracting attention as a cheap and earth‐abundant cathode material for sodium‐ion batteries, offering more stable cycling performance than other layered materials due to its special structural ordering. Developments and applications in aqueous and nonaqueous electrolyte solutions are reviewed, and problems and possible solutions are discussed in detail.

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