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Feb 2022 • Applied Surface Science

Energy hot spots distribution on groove surface, elucidated by hybrid optical model in illuminated SOI photo-polarized-activated modulator

David Glukhov, Avihu Zechariah Levi, Zeev Zalevsky, Avi Karsenty

A polarizer transistor sharing a groove filtering aperture was developed. In the device, entitled Silicon-On-Insulator Photo-Polarized Activated Modulator (SOIP2AM), one could think that the larger the V-groove, the higher is the absorbed illumination, and consequently the higher is the amount of new generated pairs of electrons-holes inside the device. In fact, the higher the illumination, the higher the destructive interference points inside the V-groove. Establishing a strong correlation between electrical and optical phenomena, two physical assumptions are presented. The first one is that observed “hot spots” (i.e. intense electrical field areas), are in fact the mirror of optical constructive interferences near the walls of the V-groove. The second assumption is that the closer the hot spots near the wall, the higher the generation of pairs of electrons-holes, since more absorbed photons. A new method, based on analytical …

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Feb 2022 • Biophysical Journal

Dynamical interplay between the human high-affinity copper transporter hCtr1 and its cognate metal ion

Gulshan Walke, Jana Aupič, Hadeel Kashoua, Pavel Janoš, Shelly Meron, Yulia Shenberger, Zena Qasem, Lada Gevorkyan-Airapetov, Alessandra Magistrato, Sharon Ruthstein

Abnormal cellular copper levels have been clearly implicated in genetic diseases, cancer, and neurodegeneration. Ctr1, a high affinity copper transporter, is an homotrimeric integral membrane protein that provides the main route for cellular copper uptake. Together with a sophisticated copper transport system, Ctr1 regulates Cu(I) metabolism in eukaryotes. Despite its pivotal role in normal cell function, the molecular mechanism of copper uptake and transport via Ctr1 remains elusive. In this study, electron paramagnetic resonance (EPR), UV-visible spectroscopy, and all-atom simulations were employed to explore Cu(I) binding to full-length human Ctr1 (hCtr1), thereby elucidating how metal binding at multiple distinct sites affects the hCtr1 conformational dynamics. We demonstrate that each hCtr1 monomer binds up to 5 Cu(I) ions and that progressive Cu(I) binding triggers a marked structural rearrangement in the …

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Feb 2022 • The Journal of Physical Chemistry A

Vibrational Strong Light–Matter Coupling in an Open Microcavity Based on Reflective Germanium Coatings

Rena Yitzhari, Omree Kapon, Yaakov R Tischler

Open microcavities (OMCs) enable tuning of the optical resonances of a system and insertion of different materials between the mirrors. They are of large scientific interest due to their many potential applications. Using OMCs, we can observe strong light–matter coupling while tuning the cavity wavelength. Typically, dielectric Bragg reflectors (DBRs) and Au mirrors are used to form microcavities and observe vibrational strong coupling (VSC) in the middle-infrared (MIR) spectral region. Here, we make the mirrors of the OMC using thin film coatings of the semiconducting material germanium (Ge) and demonstrate VSC in the MIR region. We deposited a uniform coating of poly(methyl methacrylate) (PMMA) on one of the OMC mirrors’ inner surfaces, and then we tuned the cavity to the carbonyl stretch mode resonance at 1731 cm–1. Comparing VSC using Ge mirrors to DBRs or Au mirrors, we achieve enhanced optical …

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Feb 2022 • Physical Review E

Generalized virial equation for nonlinear multiplicative Langevin dynamics: Application to laser-cooled atoms

Gianmaria Falasco, Eli Barkai, Marco Baiesi

The virial theorem, and the equipartition theorem in the case of quadratic degrees of freedom, are handy constraints on the statistics of equilibrium systems. Their violation is instrumental in determining how far from equilibrium a driven system might be. We extend the virial theorem to nonequilibrium conditions for Langevin dynamics with nonlinear friction and multiplicative noise. In particular, we generalize it for confined laser-cooled atoms in the semiclassical regime. The resulting relation between the lowest moments of the atom position and velocity allows to measure in experiments how dissipative the cooling mechanism is. Moreover, its violation can reveal the departure from a strictly harmonic confinement or from the semiclassical regime.

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Feb 2022 • ACS nano

Wafer-Scalable Single-Layer Amorphous Molybdenum Trioxide

Md Hasibul Alam, Sayema Chowdhury, Anupam Roy, Xiaohan Wu, Ruijing Ge, Michael A Rodder, Jun Chen, Yang Lu, Chen Stern, Lothar Houben, Robert Chrostowski, Scott R Burlison, Sung Jin Yang, Martha I Serna, Ananth Dodabalapur, Filippo Mangolini, Doron Naveh, Jack C Lee, Sanjay K Banerjee, Jamie H Warner, Deji Akinwande

Feb 2022 • arXiv preprint arXiv:2202.10358

Efimov resonance position near a narrow Feshbach resonance in a mixture

Ang Li, Yaakov Yudkin, Paul S Julienne, Lev Khaykovich

In the vicinity of a narrow Feshbach resonances Efimov features are expected to be characterized by the resonance's properties rather than the van der Waals length of the interatomic potential. Although this theoretical prediction is well-established by now, it still lacks experimental confirmation. Here, we apply our recently developed three-channel model [Yudkin and Khaykovich, Phys. Rev. A 103, 063303 (2021)] to the experimental result obtained in a mass-imbalanced Li-Cs mixture in the vicinity of the narrowest resonance explored to date [Johansen at. al. Nat. Phys. 13, 731 (2017)]. We confirm that the observed position of the Efimov resonance is dictated mainly by the resonance physics while the influence of the van der Waals tail of the interatomic potential is minor. We show that the resonance position is strongly influenced by the presence of another Feshbach resonance which significantly alters the effective background scattering length at the narrow resonance position.

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Feb 2022 • Biophysical Journal

Characterization of a large gated SPAD array for widefield NIR fluorescence lifetime imaging in vitro and in vivo

Jason T Smith, Alena Rudkouskaya, Shan Gao, Arin Ulku, Claudio Bruschini, Edoardo Charbon, Shimon Weiss, Margarida MR Barroso, Xavier Intes, Xavier Michalet

Optical imaging (OI) has become the most used alternative imaging tool for pre-clinical studies. Among all molecular imaging modalities, fluorescence optical imaging is central thanks to its high sensitivity, the numerous molecular probes available (either endogenous or exogenous) and its ability to simultaneously image multiple biomarkers or biological processes at various spatio-temporal scales. Especially, fluorescence lifetime imaging (FLI) has become an increasingly popular method, as it provides unique insights into the cellular micro-environment by non-invasively examining numerous intracellular parameters such as metabolic status, reactive oxygen species and intracellular pH. Moreover, FLI’s exploitation of native fluorescent signatures has been extensively investigated for enhanced diagnostic of numerous pathologies. However, to perform such measurements in intact, live specimen, it is required to …

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Feb 2022 • Proc. of SPIE Vol 11979, 1197901-1, 2022

Frontiers in Biological Detection: From Nanosensors to Systems XIV

Benjamin L Miller, Sharon M Weiss

The papers in this volume were part of the technical conference cited on the cover and title page. Papers were selected and subject to review by the editors and conference program committee. Some conference presentations may not be available for publication. Additional papers and presentation recordings may be available online in the SPIE Digital Library at SPIEDigitalLibrary. org.

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Feb 2022 • Physical Review Applied

Visualizing Current in Superconducting Networks

X Wang, M Laav, I Volotsenko, A Frydman, B Kalisky

We present an experimental study of local magnetic imaging in order to visualize the current flow in superconducting networks. We track the evolution of the spatial distribution of the current flow as the network is driven from fully superconducting to fully normal phases. Our results highlight the factors that contribute to the disordered flow in superconducting networks during their collapse, and demonstrate that the current is never uniformly distributed in the network. These results can assist the design and development of circuits based on superconductors and Josephson junctions.

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Feb 2022 • Optics Express

Classification of fluorescent anisotropy decay based on the distance approach in the frequency domain

Gilad Yahav, Yitzchak Weber, Hamootal Duadi, Shweta Pawar, Dror Fixler

Frequency domain Analysis of FI and FA decays and S2. Mathematical formulation of FI and FA decays

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Feb 2022 • Biophysical Journal

Bacterial resting membrane potential: a case study with Bacillus subtilis

Debjit Roy, Xavier Michalet, Evan W Miller, Robert P Gunsalus, Robert T Clubb, Shimon Weiss

Bacterial membrane potential changes (Δψ) play an important role in bacterial metabolism and cellular processes as well as cell to cell communications in a biofilm. However, existing tools for reading Δψ quantitatively in individual bacterial cells as well as in bacterial communities are limited. A fluorescence lifetime imaging microscopy (FLIM) technique in combination with photo-induced electron transfer (PeT) based small molecule voltage sensitive dyes have been employed to quantify absolute resting membrane potential for individual Bacillus subtilis cells. The local electrostatic potential affects the relative extent of PeT in these dyes and thus alters fluorescence quantum yield (and hence fluorescence intensity as well as fluorescence lifetime). When localized into the bacterial cell membrane, the extent of PeT gets modulated by the resting membrane potential of the system. The suitability and voltage sensitivity of …

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Feb 2022 • Analytical Chemistry

Identification of Enantiomers Using Low-Frequency Raman Spectroscopy

Vinayaka Harshothama Damle, Hagit Aviv, Yaakov R Tischler

Distinguishing between d and l enantiomers is of important scientific interest, especially for the pharmaceutical industry. Enantiomeric differentiation in the solid form is repeatedly presented as a challenge in the research community. Raman spectroscopy is a nondestructive tool, widely used for the characterization of different materials by probing their vibrational modes. The low-frequency region of the Raman spectrum reveals lattice-level interactions and global fluctuations in the molecule. Lower frequencies correspond to vibrations arising from weaker bonds and long-range interactions and hence are very susceptible to polarization changes. This work presents low-frequency Raman (LFR) spectroscopy as a facile technique to identify enantiomers. The optical setup of conventional Raman spectroscopy is engineered such that the excitation and collection geometries use an asymmetrical focal cone. In addition, a …

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Jan 2022 • Univ. of California, Los Angeles, CA (United States), 2022

Data for" In vitro and in vivo NIR Fluorescence Lifetime Imaging with a time-gated SPAD camera"

Jason T Smith, Alena Rudkouskaya, Shan Gao, Juhi M Gupta, Arin Ulku, Claudio Bruschini, Edoardo Charbon, Shimon Weiss, Margarida Barroso, Xavier Intes, Xavier Michalet

Near-infrared (NIR) fluorescence lifetime imaging (FLI) provides a unique contrast mechanism to monitor biological parameters and molecular events in vivo. Single-photon avalanche diode (SPAD) cameras have been recently demonstrated in FLI microscopy (FLIM) applications, but their suitability for in vivo macroscopic FLI (MFLI) in deep tissues remains to be demonstrated. Herein, we report in vivo NIR MFLI measurement with SwissSPAD2, a large time-gated SPAD camera. We first benchmark its performance in well-controlled in vitro experiments, ranging from monitoring environmental effects on fluorescence lifetime, to quantifying Förster resonant energy transfer (FRET) between dyes. Next, we use it for in vivo studies of target-drug engagement in live and intact tumor xenografts using FRET. Information obtained with SwissSPAD2 was successfully compared to that obtained with a gated intensified charge-coupled device (ICCD) camera, using two different approaches. Our results demonstrate that SPAD cameras offer a powerful technology for in vivo preclinical applications in the NIR window.

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Jan 2022 • Optics Continuum

Analysis and simulation of optical spectral phase encoding using an array of Fabri-Perot interferometers and code division multiplexing

Shay Yederman, Zeev Zalevsky

This paper proposes a method for a scheme of spectral phase encoding with resolution of up to 10 MHz and addressability of 40GHz, for a typical wide-band optical data carrying signal, by means of optical instruments and prior knowledge about the signal. The setup includes an array of Fabri-Perot Interferometers (FPI) which bypass the grating limitations, and a phase-only spatial light modulator (SLM) to properly encode the diffracted light. Their arrangement along with the method of Optical Code Division Multiple Access (OCDMA) was simulated, and promised fine results for various encoding schemes.

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Jan 2022 • bioRxiv

Electrically Controlling and Optically Observing the Membrane Potential of Supported Lipid Bilayers

Shimon Yudovich, Adan Marzouqe, Joseph Kantorovitsch, Eti Teblum, Tao Chen, Jorg Enderlein, Evan W Miller, Shimon Weiss

Supported lipid bilayers are a well-developed model system for the study of membranes and their associated proteins, such as membrane channels, enzymes, and receptors. These versatile model membranes can be made from various components, ranging from simple synthetic phospholipids to complex mixtures of constituents, mimicking the cell membrane with its relevant physiochemical and molecular phenomena. In addition, the high stability of supported lipids bilayers allows for their study via a wide array of experimental probes. In this work, we describe a platform for supported lipid bilayers that is accessible both electrically and optically. We show that the polarization of the supported membrane can be electrically controlled and optically probed using voltage-sensitive dyes. Membrane polarization dynamics is understood through electrochemical impedance spectroscopy and the analysis of the equivalent electrical circuit. We also describe the effect of the conducting electrode layer on the fluorescence of the optical probe through metal-induced energy transfer. We conclude with a discussion on possible applications of this platform for the study of voltage-dependent membrane proteins and other processes in membrane biology and surface science.

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Jan 2022 • Optics Express

Single-shot analysis of amplified correlated light

Sara Meir, Avi Klein, Hamootal Duadi, Eliahu Cohen, Moti Fridman

Correlated beams are important in classical and quantum communication as well as other technologies. However, classical amplifiers, which are essential for long transmission of correlated beams, degrade the correlation due to noise and due to the amplifier spectral response. We measure, with a novel high resolution single-shot measurement system, the impact of amplifiers on correlated beams. We develop a new method for analyzing the correlation between the signal and idler beams by choosing peaks in the pulses according to their power levels. We demonstrate how to tailor the correlation after the amplifier to obtain either higher or lower correlation. Our research may influence the future use of amplifiers in non-classical communication systems as well as the transmission of quantum information over long distances.

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Jan 2022 • bioRxiv

Reliability and accuracy of single-molecule FRET studies for characterization of structural dynamics and distances in proteins

Ganesh Agam, Christian Gebhardt, Milana Popara, Rebecca Maechtel, Julian Folz, Ben Ambrose, Neharika Chamachi, Sang Yoon Chung, Timothy D Craggs, Marijn de Boer, Dina Grohmann, Taekjip Ha, Andreas Hartmann, Jelle Hendrix, Verena Hirschfeld, Christian G Huebner, Thorsten Hugel, Dominik Kammerer, Hyun Seo Kang, Achillefs Kapanidis, Georg Krainer, Kevin Kramm, Edward Lemke, Eitan Lerner, Emmanuel Margeat, Kirsten Martens, Jens Michaelis, Jaba Mitra, Gustavo G Moya Munoz, Robert Quast, Nicole Robb, Michael Sattler, Michael Schlierf, Jonathan Schneider, Tim Schroeder, Anna Sefer, Piau Siong Tan, Johann Thurn, Philip Tinnefeld, John van Noort, Shimon Weiss, Nicolas Wendler, Anders Barth, Claus AM Seidel, Don C Lamb, Thorben Cordes

Single-molecule FRET (smFRET) has become an established tool to study biomolecular structure and dynamics in vitro and in live cells. We performed a worldwide blind study involving 19 labs to assess the uncertainty of FRET experiments for proteins with respect to the measured FRET efficiency histograms, determination of distances, and the detection and quantification of structural dynamics. Using two protein systems that undergo distinct conformational changes, we obtained an uncertainty of the FRET efficiency of less than 0.06, corresponding to an interdye distance precision of less than 0.2 nm and accuracy of less than 0.5 nm. We further discuss the limits for detecting distance fluctuations with sensitivity down to less than 10% of the Foerster distance and provide guidelines on how to detect potential dye perturbations. The ability of smFRET experiments to simultaneously measure distances and avoid averaging of conformational dynamics slower than the fluorescence lifetime is unique for dynamic structural biology.

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Jan 2022 • bioRxiv

Long chain lipids facilitate insertion of large nanoparticles into membranes of small unilamellar vesicles

Adan Marzouq, Lion Morgenstein, Shimon Yudovich, Ayelet Atkins, Asaf Grupi, Weiss Shimon

Insertion of hydrophobic nanoparticles into phospholipid bilayers is limited to small particles that can incorporate into the hydrophobic membrane core in between the two lipid leaflets. Incorporation of nanoparticles above this size limit requires development of challenging surface engineering methodologies. In principle, increasing membrane thickness should facilitate incorporation of larger nanoparticles. Here we explore the effect of very long phospholipids (C24:1) in small unilamellar vesicles, on the membrane insertion efficiency of nanoparticles in the range of 5-13 nm in diameter. To this end, we improved an existing vesicle preparation protocol and utilized cryogenic electron microscopy imaging to examine the mode of interaction and to evaluate the membrane insertion efficiency of membrane-inserted nanoparticles.

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Jan 2022 • ACS Applied Materials & Interfaces

Chemical Vapor Deposition of Spherical Amorphous Selenium Mie Resonators for Infrared Meta-Optics

Danveer Singh, Michal Poplinger, Avraham Twitto, Rafi Snitkoff, Pilkhaz Nanikashvili, Ori Azolay, Adi Levi, Chen Stern, Gili Cohen Taguri, Asaf Albo, Doron Naveh, Tomer Lewi

Applying direct growth and deposition of optical surfaces holds great promise for the advancement of future nanophotonic technologies. Here, we report on a chemical vapor deposition (CVD) technique for depositing amorphous selenium (a-Se) spheres by desorption of selenium from Bi2Se3 and re-adsorption on the substrate. We utilize this process to grow scalable, large area Se spheres on several substrates and characterize their Mie-resonant response in the mid-infrared (MIR) spectral range. We demonstrate size-tunable Mie resonances spanning the 2–16 μm spectral range for single isolated resonators and large area ensembles. We further demonstrate strong absorption dips of up to 90% in ensembles of particles in a broad MIR range. Finally, we show that ultra-high-Q resonances arise in the case where Se Mie-resonators are coupled to low-loss epsilon-near-zero (ENZ) substrates. These findings …

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Jan 2022 • Journal of The Electrochemical Society

A Study of Composite Solid Electrolytes: The Effect of Inorganic Additives on the Polyethylene Oxide-Sodium Metal Interface

Shaul Bublil, Yuval Elias, Diana Golodnitsky, Miryam Fayena-Greenstein, Doron Aurbach

High electrolyte-electrode interface stability is essential for solid state batteries to avoid side reactions that form interphases and voids, leading to loss of contact and increased impedance. Such detrimental situations increase overvoltage, reduce cycling efficiency, and shorten battery cycle life. While composite solid electrolytes were studied extensively, the effect of inorganic additives in the polymer matrix on the electrolyte-anode interface remains unclear. Here, solid electrolyte was studied for batteries with sodium metal anode based on polyethylene oxide (PEO) polymeric matrix containing ceramic additive. Extensive electrochemical analyses under both AC and DC conditions were performed, and chemical reactions between sodium metal and the PEO matrix, which produce interphases at the electrode-electrolyte interface, were investigated. Addition of sodium beta aluminate in the matrix appears to mitigate …

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Jan 2022 • Journal of Composites Science 6 (1), 15, 2022

A Review on Synthesis Methods of Phyllosilicate-and Graphene-Filled Composite Hydrogels

Sayan Ganguly, Shlomo Margel

This review discusses, in brief, the various synthetic methods of two widely-used nanofillers; phyllosilicate and graphene. Both are 2D fillers introduced into hydrogel matrices to achieve mechanical robustness and water uptake behavior. Both the fillers are inserted by physical and chemical gelation methods where most of the chemical gelation, ie, covalent approaches, results in better physical properties compared to their physical gels. Physical gels occur due to supramolecular assembly, van der Waals interactions, electrostatic interactions, hydrophobic associations, and H-bonding. For chemical gelation, in situ radical triggered gelation mostly occurs.

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