Sep 2020 • Cells
Ella Alkalay, Chen Gam Ze Letova Refael, Irit Shoval, Noa Kinor, Ronit Sarid, Yaron Shav-Tal
RNA-binding proteins, particularly splicing factors, localize to sub-nuclear domains termed nuclear speckles. During certain viral infections, as the nucleus fills up with replicating virus compartments, host cell chromatin distribution changes, ending up condensed at the nuclear periphery. In this study we wished to determine the fate of nucleoplasmic RNA-binding proteins and nuclear speckles during the lytic cycle of the Kaposi’s sarcoma associated herpesvirus (KSHV). We found that nuclear speckles became fewer and dramatically larger, localizing at the nuclear periphery, adjacent to the marginalized chromatin. Enlarged nuclear speckles contained splicing factors, whereas other proteins were nucleoplasmically dispersed. Polyadenylated RNA, typically found in nuclear speckles under regular conditions, was also found in foci separated from nuclear speckles in infected cells. Poly (A) foci did not contain lncRNAs known to colocalize with nuclear speckles but contained the poly (A)-binding protein PABPN1. Examination of the localization of spliced viral RNAs revealed that some spliced transcripts could be detected within the nuclear speckles. Since splicing is required for the maturation of certain KSHV transcripts, we suggest that the infected cell does not dismantle nuclear speckles but rearranges their components at the nuclear periphery to possibly serve in splicing and transport of viral RNAs into the cytoplasm. View Full-Text
Show moreSep 2020 • Journal of Solid State Electrochemistry
David Malka, Netanel Shpigel, Ran Attias, Doron Aurbach
This original article contained a mistake.
Show moreSep 2020 • Review of Scientific Instruments
Yuxiao Wu, S Dutta, J Jesudasan, A Frydman, A Roy
We describe an alternating current method to measure the Nernst effect in superconducting thin films at low temperatures. The Nernst effect is an important tool in the understanding of superconducting fluctuations and, in particular, vortex motion near critical points. However, in most materials, the Nernst signal in a typical experimental setup rarely exceeds a few μV, in some cases being as low as a few nV. DC measurements of such small signals require extensive signal processing and protection against stray pickups and offsets, limiting the sensitivity of such measurements to >1 nV. Here, we describe a method utilizing a one-heater-two-thermometer setup with the heating element and thermometers fabricated on-chip with the sample, which helped to reduce the thermal load and temperature lag between the substrate and the thermometer. Using AC heating power and 2ω measurement, we are able to achieve …
Show moreSep 2020 • Journal of The Electrochemical Society
Boryann Liaw, Thomas P Barrera, Doron Aurbach
Battery reliability and safety are two key issues critically affecting the sustainability of battery technology and the entire supply chain. Reliability and safety are interrelated and inseparable. In this focus issue, sixty (60) articles have been published online. This is quite an accomplishment for the Journal of The Electrochemical Society, indicative of the importance of this subject matter. We would like to take this opportunity to emphasize the meaning of reliability and safety in a proper context. Reliability, in principle, refers to a cell’s ability to sustain its functionality for the intended use, not only in performance but also in consistency for all aspects of the functions and for resilience in the event of failures. The reliability issues could range from a material’s electrochemical stability, an electrode’s architectural stability, and a cell’s energetic stability under the influences of external stress factors (such as mechanical stresses …
Show moreSep 2020 • Langmuir
Sven Festersen, Benjamin Runge, Christian Koops, Florian Bertram, Ben Ocko, Moshe Deutsch, Bridget M Murphy, Olaf M Magnussen
Detailed in operando studies of electrochemically induced PbBrF deposition at the liquid mercury/liquid electrolyte interface are presented. The nucleation and growth were monitored using time-resolved X-ray diffraction and reflectivity combined with electrochemical measurements, revealing a complex potential-dependent behavior. PbBrF deposition commences at potentials above −0.7 V with the rapid formation of an ultrathin adlayer of one unit cell thickness, on top of which (001)-oriented three-dimensional crystallites are formed. Two potential regimes are identified. At low overpotentials, slow growth of a low surface density film of large crystals is observed. At high overpotentials, crossover to a potential-independent morphology occurs, consisting of a compact PbBrF deposit with a saturation thickness of 25 nm, which forms within a few minutes. This potential behavior can be rationalized by the increasing …
Show moreSep 2020 • Investigative Ophthalmology & Visual Science
Revital Schick, Nairouz Farah, Amos Markus, Alon Korngreen, Yossi Mandel
Purpose: Photoreceptor precursor cells (PRPs) differentiated from human embryonic stem cells can serve as a source for cell replacement therapy aimed at vision restoration in patients suffering from degenerative diseases of the outer retina, such as retinitis pigmentosa and AMD. In this work, we studied the electrophysiologic maturation of PRPs throughout the differentiation process.Methods: Human embryonic stem cells were differentiated into PRPs and whole-cell recordings were performed for electrophysiologic characterization at days 0, 30, 60, and 90 along with quantitative PCR analysis to characterize the expression level of various ion channels, which shape the electrophysiologic response. Finally, to characterize the electrically induced calcium currents, we employed calcium imaging (rhod4) to visualize intracellular calcium dynamics in response to electrical activation.Results: Our results revealed an early and steady presence (approximately 100% of responsive cells) of the delayed potassium rectifier current. In contrast, the percentage of cells exhibiting voltage-gated sodium currents increased with maturation (from 0% to almost 90% of responsive cells at 90 days). Moreover, calcium imaging revealed the presence of voltage-gated calcium currents, which play a major role in vision formation. These results were further supported by quantitative PCR analysis, which revealed a significant and continuous (3-to 50-fold) increase in the expression of various voltage-gated channels concomitantly with the increase in the expression of the photoreceptor marker CRX.Conclusions: These results can shed light on the electrophysiologic …
Show moreSep 2020 • arXiv e-prints
Gopi Nath Daptary, Eyal Walach, Efrat Shimshoni, Aviad Frydman
Two-dimensional (2D) materials, composed of single atomic layers, have attracted vast research interest since the breakthrough discovery of graphene. One major benefit of such systems is the simple ability to tune the chemical potential by back-gating, in-principle enabling to vary the Fermi level through the charge neutrality point, thus tuning between electron and hole doping. For 2D Superconductors, this means that one may potentially achieve the strongly-coupled superconducting regime described by Bose Einstein Condensation physics of small bosonic tightly bound electron pairs. Furthermore, it should be possible to access both electron and hole based superconductivity in a single system. However, in most 2D materials, an insulating gap opens up around the charge neutrality point, thus preventing approach to this regime. Graphene is unique in this sense since it is a true semi-metal in which the un …
Show moreSep 2020 • Frontiers in Optics, FTu8B. 6, 2020
Nadav Shabairou, Maor Tiferet, Zeev Zalevsky, Moshe Sinvani
We demonstrate the shaping and focusing of a probe IR (λ= 1.55 μm) laser beam in silicon. The shaping was done by a second pump laser beam at λ= 0.775 μm and 30ps pulse width which simultaneously and collinearly, illuminates the silicon surface with the IR beam. The shaped probe beam will be used in silicon nanoscopy.
Show moreSep 2020 • Laser Science, JTu1A. 17, 2020
Maor Tiferet, Nadav Shabairou, Zeev Zalevsky, Moshe Sinvani
We demonstrate a new experimental algorithm for the diffusion length all optical measurement. This Measurement method is based on a novel Plasma Dispersion Effect based on beam shaping method that we demonstrated in the past.
Show moreSep 2020 • arXiv preprint arXiv:2009.03930
Dilip Paneru, Amit Te'eni, Bar Y Peled, James Hubble, Yingwen Zhang, Avishy Carmi, Eliahu Cohen, Ebrahim Karimi
Sep 2020 • arXiv preprint arXiv:2009.14603
Gopi Nath Daptary, Eyal Walach, Efrat Shimshoni, Aviad Frydman
Two-dimensional (2D) materials, composed of single atomic layers, have attracted vast research interest since the breakthrough discovery of graphene. One major benefit of such systems is the simple ability to tune the chemical potential by back-gating, in-principle enabling to vary the Fermi level through the charge neutrality point, thus tuning between electron and hole doping. For 2D Superconductors, this means that one may potentially achieve the strongly-coupled superconducting regime described by Bose Einstein Condensation physics of small bosonic tightly bound electron pairs. Furthermore, it should be possible to access both electron and hole based superconductivity in a single system. However, in most 2D materials, an insulating gap opens up around the charge neutrality point, thus preventing approach to this regime. Graphene is unique in this sense since it is a true semi-metal in which the un-gapped Dirac point is protected by the symmetries. In this work we show that single layer graphene, in which superconducting pairing is induced by proximity to regions of a low density superconductor, can be tuned from hole to electron superconductivity through the strong coupling regime. We study, both experimentally and theoretically, the vicinity of this "Superconducting Dirac point" and find an unusual situation where reflections at interfaces between normal and superconducting regions within the graphene, suppress the conductance and, at the same time, Andreev reflections maintain a large phase breaking length. In addition, the Fermi level can be adjusted so that the momentum in the normal and superconducting regimes perfectly …
Show moreSep 2020 • Scientific reports
Taly Iline-Vul, Raju Nanda, Borja Mateos, Shani Hazan, Irina Matlahov, Ilana Perelshtein, Keren Keinan-Adamsky, Gerhard Althoff-Ospelt, Robert Konrat, Gil Goobes
Details of apatite formation and development in bone below the nanometer scale remain enigmatic. Regulation of mineralization was shown to be governed by the activity of non-collagenous proteins with many bone diseases stemming from improper activity of these proteins. Apatite crystal growth inhibition or enhancement is thought to involve direct interaction of these proteins with exposed faces of apatite crystals. However, experimental evidence of the molecular binding events that occur and that allow these proteins to exert their functions are lacking. Moreover, recent high-resolution measurements of apatite crystallites in bone have shown that individual crystallites are covered by a persistent layer of amorphous calcium phosphate. It is therefore unclear whether non-collagenous proteins can interact with the faces of the mineral crystallites directly and what are the consequences of the presence of a disordered …
Show moreSep 2020 • Chaos, Solitons & Fractals
Erez Aghion, David A Kessler, Eli Barkai
We investigate the overdamped stochastic dynamics of a particle in an asymptotically flat external potential field, in contact with a thermal bath. For an infinite system size, the particles may escape the force field and diffuse freely at large length scales. The partition function diverges and hence the standard canonical ensemble fails. This is replaced with tools stemming from infinite ergodic theory. Boltzmann-Gibbs statistics, even though not normalized, still describes integrable observables, like energy and occupation times. The Boltzmann infinite density is derived heuristically using an entropy maximization principle, as well as via a first-principles calculation using an eigenfunction expansion in the continuum of low-energy states. A generalized virial theorem is derived, showing how the virial coefficient describes the delay in the diffusive spreading of the particles, found at large distances. When the process is non …
Show moreSep 2020 • Carbohydrate Polymers
Moorthy Maruthapandi, Kusha Sharma, John HT Luong, Aharon Gedanken
Polypyrrole grafted with chitosan (PPy-g-CS) and poly (pyrrole-N-(1-naphthyl) ethylenediamine, a copolymer, (COP) have been synthesized by a one-step microwave procedure with carbon dots(C-Dots) as initiators. The electrostatic interaction between the positively charged polymers and negatively charged microbial cell membranes is widely anticipated to be responsible for cellular lysis. However, Escherichia coli exposed to PPy-g-CS (zeta potential = +46.9 mV) was completely perished after 3 h while COP (zeta potential = +64.1 mV) exhibited no antimicrobial effect. The two polymers were capable of eradicating Staphylococcus aureus, implying the charged effect is the main mechanism of cell death. The two polymers could also chelate calcium and other nutrients as well as form an external barrier to suppress the penetration of essential nutrients to support microbial survival and proliferation. In particular …
Show moreSep 2020 • Gut microbes
Zijuan Chen, Ruixue Zhou, Yihua Zhang, Doudou Hao, Yu Wang, Shichao Huang, Ningning Liu, Chunmei Xia, Nissan Yissachar, Feng Huang, Yiwei Chu, Dapeng Yan
The protein translocated intimin receptor (Tir) from enteropathogenic Escherichia coli shares sequence similarity with the host cellular immunoreceptor tyrosine-based inhibition motifs (ITIMs). The ITIMs of Tir are required for Tir-mediated immune inhibition and evasion of host immune responses. However, the underlying molecular mechanism by which Tir regulates immune inhibition remains unclear. Here we demonstrated that β-arrestin 2, which is involved in the G-protein-coupled receptor (GPCR) signal pathway, interacted with Tir in an ITIM-dependent manner. For the molecular mechanism, we found that β-arrestin 2 enhanced the recruitment of SHP-1 to Tir. The recruited SHP-1 inhibited K63-linked ubiquitination of TRAF6 by dephosphorylating TRAF6 at Tyr288, and inhibited K63-linked ubiquitination and phosphorylation of TAK1 by dephosphorylating TAK1 at Tyr206, which cut off the downstream signal …
Show moreSep 2020 • Journal of Solid State Electrochemistry
David Malka, Netanel Shpigel, Ran Attias, Doron Aurbach
The purpose of this short paper is to outline important research tasks related to electrochemical power sources. In fact, we can mention four main avenues related to electrochemical science connected to energy challenges, ie energy harvesting by photovoltaic cells, hydrogen economy (hydrogen production by electrolysis, followed by its effective storage and use in fuel cells), the energy-water nexus which is related to capacitive interactions (including important topics such as capacitive deionisation and the field of supercapacitors and related devices) and electrochemical energy storage and conversion by batteries.
Show moreSep 2020 • ChemPhysChem
Diego Pontoni, Marco DiMichiel, Moshe Deutsch
The temperature (T) and cationic chain length (n) evolution of the nanoscale structure of the sub‐layering‐threshold members of a model family of room temperature ionic liquids (RTILs) is investigated by x‐ray scattering. The measured curves are computer‐resolved into individual Teubner‐Strey‐like lineshapes. The polar‐apolar layering is found to start at . Opposite n‐trends are found at for the spacings and correlation lengths associated with the diffraction patterns’ two main peaks, and assigned to a shift of balance between the two main interactions, Coulomb and van der Waals, and to increasing packing constraints due to the addition of methylenes. The spacings’ thermal expansion coefficients are found to deviate from the macroscopically‐measured values, and to anomalously decrease with increasing temperature. Finally, the reduced temperature scale, , ( melting temperature), is demonstrated to render …
Show moreSep 2020 • Engineering Research Express
Mark Golberg, Ran Califa, Javier Garcia, Zeev Zalevsky
A novel method for optimizing fast camera parameters to sense flow dynamics is presented. A wide-field statistic of the temporal auto-correlation intensity function from sample back-scattered laser light can be obtained from the high-end fast cameras that have come on to the market in recent years. Although these statistics can reveal flow dynamics within different sample regions, these cameras can be very costly. Here we investigated the impact of several key camera features such as camera frame rate, sensor exposure time, etc, on the output data (auto-correlation decay time and function fit models). The post-processing algorithm steps are described in detail, followed by the findings from in-vitro and in-vivo experiments investigating ways to re-leaf the camera parameters. The experimental results define fast-camera minimum specification requirements for the correct monitoring of normal blood flow conditions …
Show moreSep 2020 • Photonics
Nathalie Lander Gower, Silvia Piperno, Asaf Albo
We studied the temperature performance of split-well direct phonon terahertz quantum cascade lasers and found that it is limited by a lasing instability that becomes significant as the temperature increases. When the hot electrons of the upper laser level cannot scatter effectively to excited states due to the high radiative barriers of the structures, a lasing instability occurs, which limits the temperature performance. View Full-Text
Show moreSep 2020 • arXiv preprint arXiv:2009.04477
Uri Vool, Assaf Hamo, Georgios Varnavides, Yaxian Wang, Tony X Zhou, Nitesh Kumar, Yuliya Dovzhenko, Ziwei Qiu, Christina AC Garcia, Andrew T Pierce, Johannes Gooth, Polina Anikeeva, Claudia Felser, Prineha Narang, Amir Yacoby
1 arXiv: 2009.04477 v1 [cond-mat. mes-hall] 9 Sep 2020 possible hydrodynamic candidate materials, a new class of semimetals has recently been reported to exhibit strong interactions. In this work, we study the current flow in the layered semimetal tungsten ditelluride (WTe2) by imaging the local magnetic field above it using a nitrogen-vacancy (NV) defect in diamond. Our cryogenic scanning magnetometry system allows for temperatureresolved measurement with high sensitivity enabled by the long defect spin coherence. We directly measure the spatial current profile within WTe2 and find it differs substantially from the uniform profile of a Fermi liquid, indicating hydrodynamic flow. Furthermore, our temperature-resolved current profile measurements reveal an unexpected non-monotonic temperature dependence, with hydrodynamic effects strongest at∼ 20 K. We further elucidate this behavior via ab initio calculations of electron scattering mechanisms, which are used to extract a current profile using the electronic Boltzmann transport equation. These calculations show quantitative agreement with our measurements, capturing the non-monotonic temperature dependence. The combination of experimental and theoretical observations allows us to quantitatively infer the strength of electron-electron interactions in WTe2. We show these strong electron interactions cannot be explained by Coulomb repulsion alone and are predominantly phonon-mediated. This provides a promising avenue in the search for hydrodynamic flow and strong interactions in high carrier density materials.
Show moreSep 2020 • APL Photonics
Avi Klein, Inbar Sibony, Sara Meir, Hamootal Duadi, Michelle Y Sander, Moti Fridman
We demonstrate a temporal imaging system that can capture events with unknown time-of-arrival in the time domain without the need to synchronize the signal. The temporal imaging system is based on a time-lens that uses a high repetition-rate fiber laser for the pump wave together with a time-stretch scheme. After dispersion, the timing between adjacent pump pulses is smaller than the pulse width. Therefore, the signal interacts with one of the pump pulses with high probability, regardless of its arrival time. We discuss the intensity dependence and temporal aberrations of such an imaging system and demonstrate a direct temporal imaging of the buildup dynamics of solitons.
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