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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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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 • 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 • arXiv preprint arXiv:2104.03816

Transitions in the ergodicity of subrecoil-laser-cooled gases

Eli Barkai, Günter Radons, Takuma Akimoto

With subrecoil-laser-cooled atoms one may reach nano-Kelvin temperatures while the ergodic properties of these systems do not follow usual statistical laws. Instead, due to an ingenious trapping mechanism in momentum space, power-law-distributed sojourn times are found for the cooled particles. Here, we show how this gives rise to a statistical-mechanical framework based on infinite ergodic theory, which replaces ordinary ergodic statistical physics of a thermal gas of atoms. In particular, the energy of the system exhibits a sharp discontinuous transition in its ergodic properties. Physically this is controlled by the fluorescence rate, but more profoundly it is a manifestation of a transition for any observable, from being an integrable to becoming a non-integrable observable, with respect to the infinite (non-normalised) invariant density.

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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 • 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 • Advanced Functional Materials

Bipyridine Modified Conjugated Carbon Aerogels as a Platform for the Electrocatalysis of Oxygen Reduction Reaction

Leigh Peles‐Strahl, Noam Zion, Oran Lori, Naomi Levy, Galit Bar, Adi Dahan, Lior Elbaz

Aerogels offer a great platform for heterogeneous electrocatalysis owing to their high surface area and porosity. Atomically dispersed transition metal ions can be imbedded in these platforms at ultra‐high site density to make them catalytically active for various reactions. Herein, the synthesis of a new class of conjugated microporous organic aerogels that are used as covalent 3D frameworks for the electrocatalysis of oxygen reduction reaction (ORR) is reported. Modified aerogels functionalized with bipyridine ligands enable copper ion complexation in a single‐step synthesis. The aerogels’ structures are fully characterized using a wide array of spectroscopic and microscopic methods, and heat‐treated in order to make them electronically conductive. After heat treatment at 600 °C, the aerogels maintained their macrostructure and became active ORR catalysts in alkaline environment, showing high mass activity …

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Apr 2021

Solving the Conundrum of Active Site Density of PGM-free ORR Catalysts in situ Fuel Cells Using Fourier Transform Alternating Current Voltammetry

Rifael Snitkoff, Ariel Friedman, Yan Yurko, Piotr Zelenay, Alan Bond, Lior Elbaz

Advances in the development of Pt-group metal-free (PGM-free) catalysts for oxygen reduction reaction in fuel cells produced active catalysts that allow to reduce the performance gap to the incumbent Ptbased materials. However, the utilization of the state-of-the-art PGM-free catalysts in commercial applications is currently impeded by their relatively low durability. Methods designed to study catalyst degradation in operating fuel cells are critical for the understanding and ultimately solving the durability issues. This work is the first report on the use of Fourier-transformed alternating current voltammetry (FTacV) as an electrochemical method for accurately quantifying the electrochemical site density of PGM-free ORR catalysts, and following their degradation during the operation of polymer electrolyte fuel cells. Using this method we were capable of detecting changes in performance of electrochemically active species (electrocatalytic centers in this case), allowing us, for the first time, to calculate the electrochemical active site density (EASD) which is necessary for the elucidation of the degradation mechanisms of PGM-free ORR catalysts in situ fuel cells.

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Apr 2021 • ChemSusChem

Control of Molecular Catalysts for Oxygen Reduction by Variation of pH and Functional Groups

Ariel Friedman, Nagaprasad Reddy Samala, Hilah C Honig, Mariusz Tasior, Daniel T Gryko, Lior Elbaz, Ilya Grinberg

In the search for replacement of the platinum‐based catalysts for fuel cells, MN4 molecular catalysts based on abundant transition metals play a crucial role in modeling and investigation of the influence of the environment near the active site in platinum‐group metal‐free (PGM‐free) oxygen reduction reaction (ORR) catalysts. To understand how the ORR activity of molecular catalysts can be controlled by the active site structure through modification by the pH and substituent functional groups, the change of the ORR onset potential and the electron number in a broad pH range was examined for three different metallocorroles. Experiments revealed a switch between two different ORR mechanisms and a change from 2e− to 4e− pathway in the pH range of 3.5‐6. This phenomenon was shown by density functional theory (DFT) calculations to be related to the protonation of the nitrogen atoms and carboxylic acid …

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Apr 2021 • Immunologic Research

Exploring genetic defects in adults who were clinically diagnosed as severe combined immune deficiency during infancy

Ido Somekh, Atar Lev, Ortal Barel, Yu Nee Lee, Ayal Hendel, Amos J Simon, Raz Somech

Genetic diagnostic tools including whole-exome sequencing (WES) have advanced our understanding in human diseases and become common practice in diagnosing patients with suspected primary immune deficiencies. Establishing a genetic diagnosis is of paramount importance for tailoring adequate therapeutic regimens, including identifying the need for hematopoietic stem cell transplantation (HSCT) and genetic-based therapies. Here, we genetically studied two adult patients who were clinically diagnosed during infancy with severe combined immune deficiency (SCID). Two unrelated patients, both of consanguineous kindred, underwent WES in adulthood, 2 decades after their initial clinical manifestations. Upon clinical presentation, immunological workup was performed, which led to a diagnosis of SCID. The patients presented during infancy with failure to thrive, generalized erythematous rash, and …

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Apr 2021 • ChemistryOpen

Cellular Uptake of the ATSM− Cu (II) Complex under Hypoxic Conditions

Gulshan R Walke, Dr Shelly Meron, Yulia Shenberger, Lada Gevorkyan‐Airapetov, Sharon Ruthstein

The Cu (II)‐diacetyl‐bis (N4‐methylthiosemicarbazone) complex (ATSM− Cu (II)) has been suggested as a promising positron emission tomography (PET) agent for hypoxia imaging. Several in‐vivo studies have shown its potential to detect hypoxic tumors. However, its uptake mechanism and its specificity to various cancer cell lines have been less studied. Herein, we tested ATSM− Cu (II) toxicity, uptake, and reduction, using four different cell types:(1) mouse breast cancer cells (DA‐3),(2) human embryonic kidney cells (HEK‐293),(3) breast cancer cells (MCF‐7), and (4) cervical cancer cells (Hela) under normoxic and hypoxic conditions. We showed that ATSM− Cu (II) is toxic to breast cancer cells under normoxic and hypoxic conditions; however, it is not toxic to normal HEK‐293 non‐cancer cells. We showed that the Cu (I) content in breast cancer cell after treatment with ATSM− Cu (II) under hypoxic conditions is …

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Apr 2021 • Journal of Laser Micro/Nanoengineering

Influence of Nanosecond Pulse Bursts at High Repetition Rates on Ablation Process.

John Linden, Sharona Cohen, Yuval Berg, Zvi Kotler, Zeev Zalevsky

Nanosecond laser pulsed ablation is a common technique for micromachining of microelectronics. Recent laser technologies use temporal shaping of single pulses to create ‘pulse bursts’ of several short consecutive pulses at several times the laser repetition rate with a reduced peak power, achieving significantly higher average powers. In this study we tested the effects of pulse bursts on ablation of multilayer PCB. We show that by implementing temporal beam shaping, we were able to increase the throughput by a factor of 40%. To gain a deeper insight of the laser mater interactions of ablation with pulse bursts, we studied the plasma emissions and monitor the process with a time resolution of several nanoseconds. These results demonstrate the importance of temporal pulse shapes for laser micromachining in the microelectronics industry.

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Apr 2021 • OSA Continuum

Fiber based all-optical infinite impulse response filter tuned via stimulated Brillouin scattering

Sagie Asraf, Marko Šprem, Zeev Zalevsky

In this paper, we present a novel configuration for an all-fiber tunable infinite impulse response optical filter using stimulated Brillouin scattering. By applying the Brillouin acoustic waves within the coupling area of an optical coupler, we can control its transmissivity and so to affect the spectral response of the IIR optical filter. In this paper, we explain the principle of operation of the proposed device and experimentally demonstrate the ability to control the spectral response of an optical filter based on fiber ring resonator configuration.

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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 • Viruses

The Portal Vertex of KSHV Promotes Docking of Capsids at the Nuclear Pores

Daniela Dünn-Kittenplon, Asaf Ashkenazy-Titelman, Inna Kalt, Jean-Paul Lellouche, Yaron Shav-Tal, Ronit Sarid

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a cancer-related herpesvirus. Like other herpesviruses, the KSHV icosahedral capsid includes a portal vertex, composed of 12 protein subunits encoded by open reading frame (ORF) 43, which enables packaging and release of the viral genome into the nucleus through the nuclear pore complex (NPC). Capsid vertex-specific component (CVSC) tegument proteins, which directly mediate docking at the NPCs, are organized on the capsid vertices and are enriched on the portal vertex. Whether and how the portal vertex is selected for docking at the NPC is unknown. Here, we investigated the docking of incoming ORF43-null KSHV capsids at the NPCs, and describe a significantly lower fraction of capsids attached to the nuclear envelope compared to wild-type (WT) capsids. Like WT capsids, nuclear envelope-associated ORF43-null capsids co-localized with different nucleoporins (Nups) and did not detach upon salt treatment. Inhibition of nuclear export did not alter WT capsid docking. As ORF43-null capsids exhibit lower extent of association with the NPCs, we conclude that although not essential, the portal has a role in mediating the interaction of the CVSC proteins with Nups, and suggest a model whereby WT capsids can dock at the nuclear envelope through a non-portal penton vertex, resulting in an infection ‘dead end’. View Full-Text

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Apr 2021 • OSA Continuum

Ultra-fast remote photoacoustic imaging with a non-scanning speckle-based setup

Matan Benyamin, Hadar Genish, Ran Califa, Nisan Ozana, Benjamin Lengenfelder, Florian Klämpfl, Zeev Zalevsky

A method for fast non-scanning remote photoacoustic imaging is presented and experimentally demonstrated. The approach is based on speckle contrast measurement, proceeding the previously developed method for speckle contrast based photoacoustic detection. This previously developed method is now presented without the need for raster scanning of the sample, an advantage rarely found in optical photoacoustic detection, and offers 50 times faster as well as a simpler remote photoacoustic scheme in respect to interferometric available solutions.

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Apr 2021 • Advanced Functional Materials 31 (15), 2009266, 2021

Pulse dynamics of flexural waves in transformed plates

Kun Tang, Chenni Xu, Sebastien Guenneau, Patrick Sebbah

Coordinate‐transformation‐inspired optical devices have been mostly examined in the continuous‐wave regime: the performance of an invisibility cloak, which has been demonstrated for monochromatic excitation, is likely to deteriorate for short pulses. Here, pulse dynamics of flexural waves propagating in transformed plates is investigated. A practical realization of a waveshifter and a rotator for flexural waves based on the coordinate transformation method is proposed. Time‐resolved measurements reveal how the waveshifter deviates a short pulse from its initial trajectory, with no reflection at the bend and no spatial and temporal distortion of the pulse. Extending the strategy to cylindrical coordinates, a wave rotator is designed. It is demonstrated experimentally how a pulsed plane wave is twisted inside the rotator, while its wavefront is recovered behind the rotator and the pulse shape is preserved, with no extra …

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Apr 2021 • Journal of Medical Engineering & Technology

Validation of a novel contact-free heart and respiratory rate monitor

Ofer Havakuk, Ben Sadeh, Ilan Merdler, Zeev Zalevsky, Javier Garcia-Monreal, Sagi Polani, Yaron Arbel

There is a growing need for remote monitoring of patients due to a lack of resources and infection control. Current systems use sensors that require constant physical contact with the user, which may result in discomfort or lack of adherence. In the present study, we evaluated the accuracy of a new contact-free system to monitor heart and respiratory rate. Study participants were measured simultaneously using two devices: a contact-free optical system that measures nano-vibrations and movements (investigational device, “Gili Pro BioSensor”) and a standard reference bed-side monitor, inclusive of an electrocardiogram and capnograph modules (Mindray®). Co-primary endpoints included HR and RR accuracy in subjects without active arrhythmias for HR, and for all study populations for RR (i.e., for subjects with and without active arrhythmias). Confirmatory secondary endpoints included HR scored continuously for …

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Apr 2021 • IEEE Photonics Journal

Comment on “Rapid Image Reconstruction of Structured Illumination Microscopy Directly in the Spatial Domain” and More About Point Spread Function Shaping for Enhanced Imaging …

Dror Fixler, Zeev Zalevsky

During the past several decades, a variety of imaging modalities in fluorescence microscopy have emerged as powerful tools for probing the spatial and temporal dimensions in fixed and living cells and tissues to uncover structural and dynamic information. Recently, our journal accepted a paper in this topic, and we received comments. We found it as opportunity to discuss this important topic for additional angles. We believe that this discussion will be interesting and helpful to the whole community.

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Apr 2021 • arXiv preprint arXiv:2104.09321

Nonlocality in quantum time via modular operators

Ismael L Paiva, Marcin Nowakowski, Eliahu Cohen

Apr 2021 • OSA Continuum

Optical analysis of facial nerve degeneration in Bell’s palsy

Hadas Lupa Yitzhak, Michael Wolf, Nisan Ozana, Yarden Tzabari Kelman, Zeev Zalevsky

This paper is an initial proof of concept for an optical speckled-based method for the evaluation of facial nerve paralysis. Differences between the affected and the healthy sides of the face were measured in patients with Bell's palsy—a peripheral facial nerve paralysis. The patients’ faces were illuminated with two symmetrical spots on their nasolabial folds and the reflected speckle patterns were analyzed. Muscle activity was evaluated by muscle tone contraction-release motion inducing associated skin tilting movements. The skin movements were imaged with a defocused lens, which enables extraction of the speckle pattern's time changing trajectory. We found an asymmetry ratio expression that may be the key for the estimation of the degeneration level in Bell's palsy.

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