1975 articles

69 publishers

Join mailing list

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 …

Show more

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

Jan 2022 • bioRxiv

T cell receptor beta germline variability is revealed by inference from repertoire data

Aviv Omer, Ayelet Peres, Oscar L Rodrigues, Corey T Watson, William Lees, Pazit Polak, Andrew M Collins, Gur Yaari

T and B cell repertoires constitute the foundation of adaptive immunity. Adaptive immune receptor repertoire sequencing (AIRR-seq) is a common approach to study immune system dynamics. Understanding the genetic factors influencing the composition and dynamics of these repertoires is of major scientific and clinical importance. The chromosomal loci encoding for the variable regions of T and B cell receptors (TCRs and BCRs, respectively) are challenging to decipher due to repetitive elements and undocumented structural variants. To confront this challenge, AIRR-seq-based methods have been developed recently for B cells, enabling genotype and haplotype inference and discovery of undocumented alleles. Applying these methods to AIRR-seq data reveals a plethora of undocumented genomic variations. However, this approach relies on complete coverage of the receptors9 variable regions, and most T cell studies sequence only a small fraction of the variable region. Here, we adapted BCR inference methods to full and partial TCR sequences, and identified 38 undocumented polymorphisms in TRBV, 15 of them were also observed in genomic data assemblies. Further, we identified 31 undocumented 59 UTR sequences. A subset of these inferences was also observed using independent genomic approaches. We found the two documented TRBD2 alleles to be equally abundant in the population, and show that the single nucleotide that differentiates them is strongly associated with dramatic changes in the expressed repertoire. Our findings expand the knowledge of genomic variation in the TRB (T Cell Receptor Beta) locus and …

Show more

Jan 2022 • ACS Omega

CVD-Assisted Synthesis of 2D Layered MoSe2 on Mo Foil and Low Frequency Raman Scattering of Its Exfoliated Few-Layer Nanosheets on CaF2 Substrates

Rajashree Konar, Bharathi Rajeswaran, Atanu Paul, Eti Teblum, Hagit Aviv, Ilana Perelshtein, Ilya Grinberg, Yaakov Raphael Tischler, Gilbert Daniel Nessim

Transition-metal dichalcogenides (TMDCs) are unique layered materials with exotic properties. So, examining their structures holds tremendous importance. 2H-MoSe2 (analogous to MoS2; Gr. 6 TMDC) is a crucial optoelectronic material studied extensively using Raman spectroscopy. In this regard, low-frequency Raman (LFR) spectroscopy can probe this material’s structure as it reveals distinct vibration modes. Here, we focus on understanding the microstructural evolution of different 2H-MoSe2 morphologies and their layers using LFR scattering. We grew phase-pure 2H-MoSe2 (with variable microstructures) directly on a Mo foil using a two-furnace ambient-pressure chemical vapor deposition (CVD) system by carefully controlling the process parameters. We analyzed the layers of exfoliated flakes after ultrasonication and drop-cast 2H-MoSe2 of different layer thicknesses by choosing different concentrations of …

Show more

Jan 2022 • ACS Applied Nano Materials

Acoustic Green Synthesis of Graphene-Gallium Nanoparticles and PEDOT: PSS Hybrid Coating for Textile To Mitigate Electromagnetic Radiation Pollution

Poushali Das, Sayan Ganguly, Ilana Perelshtein, Shlomo Margel, Aharon Gedanken

Jan 2022 • The CRISPR Journal

High-throughput Imaging of CRISPR-and Recombinant Adeno-associated Virus–induced DNA Damage Response in Human Hematopoietic Stem and Progenitor Cells

Daniel Allen, Lucien E Weiss, Alon Saguy, Michael Rosenberg, Ortal Iancu, Omri Matalon, Ciaran Lee, Katia Beider, Arnon Nagler, Yoav Shechtman, Ayal Hendel

CRISPR-Cas technology has revolutionized gene editing, but concerns remain due to its propensity for off-target interactions. This, combined with genotoxicity related to both CRISPR-Cas9-induced double-strand breaks and transgene delivery, poses a significant liability for clinical genome-editing applications. Current best practice is to optimize genome-editing parameters in preclinical studies. However, quantitative tools that measure off-target interactions and genotoxicity are costly and time-consuming, limiting the practicality of screening large numbers of potential genome-editing reagents and conditions. Here, we show that flow-based imaging facilitates DNA damage characterization of hundreds of human hematopoietic stem and progenitor cells per minute after treatment with CRISPR-Cas9 and recombinant adeno-associated virus serotype 6. With our web-based platform that leverages deep learning for …

Show more

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 …

Show more

Jan 2022 • ACS Applied Nano Materials

Acoustic Green Synthesis of Graphene-Gallium Nanoparticles and PEDOT: PSS Hybrid Coating for Textile To Mitigate Electromagnetic Radiation Pollution

Poushali Das, Sayan Ganguly, Ilana Perelshtein, Shlomo Margel, Aharon Gedanken

Solid matrix-supported liquid metal nanoparticles have been drawing attention as a nanoadditive in the fabrication of electroconductive flexible and soft materials. The present work reports a facile, green, and sonochemical synthesis approach of gallium (Ga) nanoparticles embedded in reduced graphene oxide (RGO) under ambient conditions for the first time. The as-synthesized ultrasonic energy-irradiated RGO/Ga nanocomposite was studied using SEM, TEM, DSC, XRD, XPS, and solid-state NMR. Because of their electrical conductivity, RGO/Ga nanoparticles have been used as a conducting inclusion for a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) matrix and coated on cotton fabrics to develop a smart e-textile for electromagnetic (EM) radiation-shielding application. In the X-band (8.2–12.4 GHz) frequency range, the nanocomposites’ EM interference-shielding efficiency was about …

Show more

Jan 2022 • arXiv preprint arXiv:2201.12749

Large-scale behavior of energy spectra of the quantum random antiferromagnetic Ising chain with mixed transverse and longitudinal fields

Richard Berkovits

In recent years it became clear that the metallic regime of systems that exhibit a many body localization (MBL) behavior show properties which are quite different than the vanilla metallic region of the single particle Anderson regime. Here we show that the large scale energy spectrum of a canonical microscopical model featuring MBL, displays a non-universal behavior at intermediate scales, which is distinct from the deviation from universality seen in the single particle Anderson regime. The crucial step in revealing this behavior is a global unfolding of the spectrum performed using the singular value decomposition (SVD) which takes into account the sample to sample fluctuations of the spectra. The spectrum properties may be observed directly in the singular value amplitudes via the scree plot, or by using the SVD to unfold the spectra and then perform a number of states variance calculation. Both methods reveal an intermediate scale of energies which follow super Posissonian statistics.

Show more

Jan 2022 • ACS Catalysis

Recent Progress and Viability of PGM-Free Catalysts for Hydrogen Evolution Reaction and Hydrogen Oxidation Reaction

Wenjamin Moschkowitsch, Oran Lori, Lior Elbaz

The global energy demand is expected to rise continuously in the foreseeable future, and this demand cannot be fulfilled with fossil fuels if the ambitious goals for global reduction in greenhouse gas emissions are to be met. 1, 2 Therefore, it is necessary to switch to energy production from sustainable energy sources such as solar and wind. 3, 4 These sources suffer from intermittent production, producing a surplus of energy at certain hours and seasons and little to none at others. Hence, large energy storage solutions are necessary in order to store the excess energy in peak times and compensate at the lowand down-times. 4, 5One of the most promising energy storage solutions today is chemical, in the form of hydrogen, which can be used with fuel cells to generate electricity or burned to generate heat, as well as being used in the chemical industry for various applications. 5 It can be easily produced with various …

Show more

Jan 2022 • ACS Applied Energy Materials

Precious-Group-Metal-Free Energy-Efficient Urea Electrolysis: Membrane Electrode Assembly Cell Using Ni3N Nanoparticles as Catalyst

Vineesh Thazhe Veettil, Anagha Usha Vijayakumar, Aviv Ashdot, David Zitoun

The sluggish kinetics of the anodic oxygen evolution reaction (OER) limit the overall efficiency of green hydrogen production. The proposed strategy to overcome this is to replace OER with other kinetically favorable anodic reactions like urea oxidation reaction (UOR). Herein, we develop an organometallic synthesis of nickel nitride nanoparticles supported on carbon (Ni3N–C) as the catalyst for both UOR and hydrogen evolution reaction (HER). A precious group metal-free electrolyzer based on Ni3N–C catalyst (as both anode and cathode) is implemented for the first time, and the urea electrolyzer cell has a 200 mV lower overpotential compared to that of the water electrolyzer.

Show more

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.

Show more

Jan 2022 • New Biotechnology

Microfluidic tool for rapid functional characterization of CRISPR complexes

Dana Peleg-Chen, Guy Shuvali, Lev Brio, Amit Ifrach, Ortal Iancu, Efrat Barbiro-Michaely, Ayal Hendel, Doron Gerber

RNA guided nucleases are regarded as the future genome editing technologies. As such, they need to meet strong safety margins. Two major challenges in incorporating CRISPR technologies into the clinical world are off-target activity and editing efficiency. The common way to tackle such issues is to measure the binding and cleavage kinetics of the CRISPR enzyme. This can be challenging since, for example, DNA is not released from the CAS9 protein post cleavage. Here a promising new microfluidic approach to characterizing Enzymatic Interaction and Function of CRISPR complexes on a microfluidic platform (EnzyMIF) is presented. The method can rapidly detect the kd, koff, km and kcat for various RNA guided nucleases. In this work, two single guide RNAs with significantly different in-cell cleavage efficiency, RAG2 and RAG1, are used as proof-of-concept. The EnzyMIF assay results provide biochemical …

Show more

Jan 2022 • Advanced Materials Interfaces

Growth of Hybrid Chiral Thin Films by Molecular Layer Deposition Zinc/Cysteine as a Case Study

Reut Yemini, Shalev Blanga, Hagit Aviv, Ilana Perelshtein, Eti Teblum, Shahar Dery, Elad Gross, Yitzhak Mastai, Malachi Noked, Ortal Lidor‐Shalev

Jan 2022 • Science advances

Peroxisome function relies on organelle-associated mRNA translation

Noa Dahan, Yury S Bykov, Elizabeth A Boydston, Amir Fadel, Zohar Gazi, Hodaya Hochberg-Laufer, James Martenson, Vlad Denic, Yaron Shav-Tal, Jonathan S Weissman, Naama Aviram, Einat Zalckvar, Maya Schuldiner

Crucial metabolic functions of peroxisomes rely on a variety of peroxisomal membrane proteins (PMPs). While mRNA transcripts of PMPs were shown to be colocalized with peroxisomes, the process by which PMPs efficiently couple translation with targeting to the peroxisomal membrane remained elusive. Here, we combine quantitative electron microscopy with proximity-specific ribosome profiling and reveal that translation of specific PMPs occurs on the surface of peroxisomes in the yeast Saccharomyces cerevisiae. This places peroxisomes alongside chloroplasts, mitochondria, and the endoplasmic reticulum as organelles that use localized translation for ensuring correct insertion of hydrophobic proteins into their membranes. Moreover, the correct targeting of these transcripts to peroxisomes is crucial for peroxisomal and cellular function, emphasizing the importance of localized translation for cellular physiology.

Show more

Jan 2022 • Scientific Reports

Picosecond pulsed laser illumination: an ultimate solution for photonic versus thermal processes’ contest in SOI photo-activated modulator

David Glukhov, Zeev Zalevsky, Avi Karsenty

The functionality of a nanoscale silicon-based optoelectronic modulator is deeply analyzed while it appears that two competing processes, thermal and photonic, are occurring at the same time, and are preventing the optimization of the electro-optics coupling. While an incident illumination-beam first process is translated into photons, generating pairs of electrons–holes, a second process of thermal generation, creating phonons enables a loss of energy. Complementary studies, combining strong analytical models and numerical simulations, enabled to better understand this competition between photonic and thermal activities, in order to optimize the modulator. Moreover, in order to prevent unnecessary heating effects and to present a proposed solution, a picosecond pulsed laser is suggested and demonstrated as the ultimate solution so no energy will be wasted in heat, and still the photonic energy will be fully …

Show more

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.

Show more

Jan 2022 • Optica

Chemical element mapping by x-ray computational ghost fluorescence

Yishay Klein, Or Sefi, Hila Schwartz, Sharon Shwartz

Chemical element mapping is an imaging tool that provides essential information about composite materials, and it is crucial for a broad range of fields ranging from fundamental science to numerous applications. Methods that exploit x-ray fluorescence are very advantageous and are widely used, but require focusing of the input beam and raster scanning of the sample. Thus, the methods are slow and exhibit limited resolution due to focusing challenges. Here, we demonstrate an x-ray fluorescence method based on computational ghost imaging that overcomes those limitations since it does not require focusing and show that when it is combined with compressed sensing the total measurement time can be significantly reduced. Our method opens the possibility to significantly enhance the resolution of chemical element maps and to extend the applicability of x-ray fluorescence inspection to new fields where the …

Show more

Jan 2022 • Carbohydrate Polymers

Non-radical synthesis of chitosan-quercetin polysaccharide: Properties, bioactivity and applications

Yevgenia Shebis, Alexander Laskavy, Anat Molad-Filossof, Hadar Arnon-Rips, Michal Natan-Warhaftig, Gila Jacobi, Elazar Fallik, Ehud Banin, Elena Poverenov

Quercetin-chitosan (QCS) polysaccharide was synthesized via non-radical reaction using L-valine-quercetin as the precursor. QCS was systematically characterized and demonstrated amphiphilic properties with self-assembling ability. In-vitro activity studies confirmed that quercetin grafting does not diminish but rather increases antimicrobial activity of the original chitosan (CS) and provided the modified polysaccharide with antioxidative properties. QCS applied as a coating on fresh-cut fruit reduced microbial spoilage and oxidative browning of coated melon and apple, respectively. Notably, QCS-based coatings prevented moisture loss, a major problem with fresh produce (2%, 12% and 18% moisture loss for the QCS-coated, CS-coated and uncoated fruit, respectively).The prepared QCS polysaccharide provides advanced bioactivity and does not involve radical reactions during its synthesis, therefore, it has …

Show more

Jan 2022 • The Journal of Chemical Physics

Membrane potential sensing: Material design and method development for single particle optical electrophysiology

Debjit Roy, Zehavit Shapira, Shimon Weiss

We review the development of 'single' nanoparticle-based inorganic and organic voltage sensors which can eventually become a viable tool for 'non-genetic optogenetics'. The voltage sensing is accomplished with optical imaging at the fast temporal response and high spatial resolutions in a large field of view. Inorganic voltage nanosensors utilize the Quantum Confined Stark effect (QCSE) to sense local electric fields. Engineered nanoparticles achieve substantial single-particle voltage sensitivity (~2% Δ spectral Stark shift, up to ~30% ΔF/F per 160 mV) at room temperature due to enhanced charge separation. A dedicated home build fluorescence microscope records spectrally resolved images to measure QCSE induced spectral shift at the single-particle level. Biomaterial based surface ligands are designed and developed based on theoretical simulations. The hybrid nanobiomaterials satisfies anisotropic …

Show more

Jan 2022 • arXiv preprint arXiv:2201.09386

Impact of Non-Hermiticity and Nonlinear Interactions on Disordered-Induced Localized Modes

Bhupesh Kumar, Patrick Sebbah

If disorder-induced Anderson localized states have been observed experimentally in optics, their study remains challenging leaving a number of open questions unsolved. Among them, the impact on Anderson localization of non-Hermiticity, optical gain and loss, and more generally, nonlinearities has been the subject of numerous theoretical debates, without yet any conclusive experimental demonstration. Indeed, in systems where localized modes have reasonable spatial extension to be observed and investigated, their mutual interaction and coupling to the sample boundaries make it extremely difficult to isolate them spectrally and investigate them alone. Recently, we successfully exhibited localized lasing modes individually in an active disordered medium, using pump-shaping optimization technique. However, a one-to-one identification of the lasing modes with the eigenmodes of the passive system was not possible, as the impact of non-Hermiticity and nonlinear gain on these localized states was unknown. Here, we apply the pump-shaping method to fully control the non-Hermiticity of an active scattering medium. Direct imaging of the light distribution within the random laser allows us to demonstrate unequivocally that the localized lasing modes are indeed the modes of the passive system. This opens the way to investigate the robustness of localized states in the presence of nonlinear gain and nonlinear modal interactions. We show that, surprisingly, gain saturation and mode competition for gain does not affect the spatial distribution of the modes.

Show more


Powered by Articali