3692 articles

75 publishers

Join mailing list

Mar 2022 • APL Photonics

Reduced material loss in thin-film lithium niobate waveguides

Amirhassan Shams-Ansari, Guanhao Huang, Lingyan He, Zihan Li, Jeffrey Holzgrafe, Marc Jankowski, Mikhail Churaev, Prashanta Kharel, Rebecca Cheng, Di Zhu, Neil Sinclair, Boris Desiatov, Mian Zhang, Tobias Kippenberg, Marko Loncar

Thin-film lithium niobate has shown promise for scalable applications ranging from single-photon sources to high-bandwidth data communication systems.Realization of the next generation high-performance classical and quantum devices, however, requires much lower optical losses than the current state of the art resonator (Q-factor of 10 million). Yet material limitations of ion-sliced thin film lithium niobate have not been explored, and therefore it is unclear how high the quality factor can be achieved in this platform. Here, using our newly developed characterization method, we find out that the material limited quality factor of thin film lithium niobate photonic platform can be improved using post-fabrication annealing, and can be as high as Q~1.6×108 at telecommunication wavelengths, corresponding to a propagation loss of ~0.2 dB/m.

Show more

Mar 2022 • Polymers for Advanced Technologies

Electrospinning of polymer nanofibers based on chiral polymeric nanoparticles

Meir Abuaf, Yitzhak Mastai

Chiral polymeric nanoparticles (NPs) have emerged as a new and exciting field of research and in the last years due to their possible use for many applications in chiral chemistry however the efficiency of separating enantiomerically pure compounds has been always challenging. In this article, we focus on electrospun nanofibers formed by chiral functional NPs based on leucine or phenylalanine amino acids with polysulfone (PSF). Combining chiral functional NPs with PSF in electrospinning method provides us to get intertwined electrospun membranes with chiral property and used them for separation of racemic mixtures. We have also studied chiral functional conventional membranes formed by PSF and NPs. The NPs were prepared by miniemulsion polymerization and were characterized by DLS, SEM, MS, and NMR and display spherical structure with a narrow size distribution in the range of 200 to 250 nm …

Show more

Mar 2022 • Proceedings of the National Academy of Sciences

Halide perovskite dynamics at work: Large cations at 2D-on-3D interfaces are mobile

Sujit Kumar, Lothar Houben, Katya Rechav, David Cahen

Ultra-thin hydrophobic capping layers of two-dimensional (2D) onto three-dimensional (3D) metal halide perovskites (HaPs) are an attractive strategy for preventing ambient-induced degradation and minimizing interfacial non-idealities of 3D HaPs. However, it is not obvious in how far the unusual 3D HaP lattice dynamics affect 2D-on-3D HaP composites’ stability, especially at their interface, an issue important for devices made with such composites. Using low electron–fluence, four-dimensional scanning transmission electron microscopy and nanobeam electron diffraction, we show formation of the 2D (n = 1) phase on top of 3D perovskite, using focused-ion beam-prepared cross-sections, under conditions that minimize radiation damage. The 2D-on-3D HaP composites were prepared by controlled gas-phase surface cation exchange of 3D MAPbI3 films to form A2PbI4, where A = (fluoro-)phenyl-ethyl-ammonium …

Show more

Mar 2022 • Nanomaterials 12 (6), 898, 2022

Synthesis of doped/hybrid carbon dots and their biomedical application

Vijay Bhooshan Kumar, Ze’ev Porat, Aharon Gedanken

Carbon dots (CDs) are a novel type of carbon-based nanomaterial that has gained considerable attention for their unique optical properties, including tunable fluorescence, stability against photobleaching and photoblinking, and strong fluorescence, which is attributed to a large number of organic functional groups (amino groups, hydroxyl, ketonic, ester, and carboxyl groups, etc.). In addition, they also demonstrate high stability and electron mobility. This article reviews the topic of doped CDs with organic and inorganic atoms and molecules. Such doping leads to their functionalization to obtain desired physical and chemical properties for biomedical applications. We have mainly highlighted modification techniques, including doping, polymer capping, surface functionalization, nanocomposite and core-shell structures, which are aimed at their applications to the biomedical field, such as bioimaging, bio-sensor applications, neuron tissue engineering, drug delivery and cancer therapy. Finally, we discuss the key challenges to be addressed, the future directions of research, and the possibilities of a complete hybrid format of CD-based materials.

Show more

Mar 2022 • Inorganics

Improved Electrochemical Behavior and Thermal Stability of Li and Mn-Rich Cathode Materials Modified by Lithium Sulfate Surface Treatment

Hadar Sclar, Sandipan Maiti, Rosy Sharma, Evan M Erickson, Judith Grinblat, Ravikumar Raman, Michael Talianker, Malachi Noked, Aleksandr Kondrakov, Boris Markovsky, Doron Aurbach

High-energy cathode materials that are Li- and Mn-rich lithiated oxides—for instance, 0.35Li2MnO3.0.65LiNi0.35Mn0.45Co0.20O2 (HE-NCM)—are promising for advanced lithium-ion batteries. However, HE-NCM cathodes suffer from severe degradation during cycling, causing gradual capacity loss, voltage fading, and low-rate capability performance. In this work, we applied an effective approach to creating a nano-sized surface layer of Li2SO4 on the above material, providing mitigation of the interfacial side reactions while retaining the structural integrity of the cathodes upon extended cycling. The Li2SO4 coating was formed on the surface of the material by mixing it with nanocrystalline Li2SO4 and annealing at 600 °C. We established enhanced electrochemical behavior with ~20% higher discharge capacity, improved charge-transfer kinetics, and higher rate capability of HE-NCM cathodes due to the presence of the Li2SO4 coating. Online electrochemical mass spectrometry studies revealed lower CO2 and H2 evolution in the treated samples, implying that the Li2SO4 layer partially suppresses the electrolyte degradation during the initial cycle. In addition, a ~28% improvement in the thermal stability of the Li2SO4-treated samples in reactions with battery solution was also shown by DSC studies. The post-cycling analysis allowed us to conclude that the Li2SO4 phase remained on the surface and retained its structure after 100 cycles.

Show more

Mar 2022 • Cell

Tumor-reactive antibodies evolve from non-binding and autoreactive precursors

Roei D Mazor, Nachum Nathan, Amit Gilboa, Liat Stoler-Barak, Lihee Moss, Inna Solomonov, Assaf Hanuna, Yalin Divinsky, Merav D Shmueli, Hadas Hezroni, Irina Zaretsky, Michael Mor, Ofra Golani, Gad Sabah, Ariella Jakobson-Setton, Natalia Yanichkin, Meora Feinmesser, Daliah Tsoref, Lina Salman, Effi Yeoshoua, Eyal Peretz, Inna Erlich, Netta Mendelson Cohen, Jonathan M Gershoni, Natalia Freund, Yifat Merbl, Gur Yaari, Ram Eitan, Irit Sagi, Ziv Shulman

The tumor microenvironment hosts antibody-secreting cells (ASCs) associated with a favorable prognosis in several types of cancer. Patient-derived antibodies have diagnostic and therapeutic potential; yet, it remains unclear how antibodies gain autoreactivity and target tumors. Here, we found that somatic hypermutations (SHMs) promote antibody antitumor reactivity against surface autoantigens in high-grade serous ovarian carcinoma (HGSOC). Patient-derived tumor cells were frequently coated with IgGs. Intratumoral ASCs in HGSOC were both mutated and clonally expanded and produced tumor-reactive antibodies that targeted MMP14, which is abundantly expressed on the tumor cell surface. The reversion of monoclonal antibodies to their germline configuration revealed two types of classes: one dependent on SHMs for tumor binding and a second with germline-encoded autoreactivity. Thus, tumor-reactive …

Show more

Mar 2022 • Journal of the American Chemical Society

Biogenic guanine crystals are solid solutions of guanine and other purine metabolites

Noam Pinsk, Avital Wagner, Lilian Cohen, Christopher JH Smalley, Colan E Hughes, Gan Zhang, Mariela J Pavan, Nicola Casati, Anne Jantschke, Gil Goobes, Kenneth DM Harris, Benjamin A Palmer

Highly reflective crystals of the nucleotide base guanine are widely distributed in animal coloration and visual systems. Organisms precisely control the morphology and organization of the crystals to optimize different optical effects, but little is known about how this is achieved. Here we examine a fundamental question that has remained unanswered after over 100 years of research on guanine: what are the crystals made of? Using solution-state and solid-state chemical techniques coupled with structural analysis by powder XRD and solid-state NMR, we compare the purine compositions and the structures of seven biogenic guanine crystals with different crystal morphologies, testing the hypothesis that intracrystalline dopants influence the crystal shape. We find that biogenic “guanine” crystals are not pure crystals but molecular alloys (aka solid solutions and mixed crystals) of guanine, hypoxanthine, and …

Show more

Mar 2022 • Materials Today Sustainability

Methyl formate and dimethyl ether electro-oxidation on PtPdSn catalyst supported on carbon nanotube decorated with carbon dots

VB Kumar, D Kashyap, H Teller, MG Gebru, A Gedanken, A Schechter

In this work, methyl formate (MF) and dimethyl ether (DME) electro-oxidation was studied on equimolar ratio Ptsingle bondPdsingle bondSn catalyst supported on Vulcan Carbon XC-72, carbon nanotubes (CNT), and CNT–nitrogen-doped carbon dots (NCDs) composite. The ternary catalyst was synthesized by the ethylene glycol-assisted thermal reduction method and NCDs were synthesized by a hydrothermal method in the presence of CNT to form CNT-NCDs composite, in which the NCDs are incorporated onto the CNT surface. The activity of the catalyst in the oxidation of MF and DME was analyzed using cyclic voltammetry and chronoamperometry techniques. The ternary catalyst supported on CNT-NCDs composite (Pt1Pd1Sn1/CNT-NCDs) showed a peak oxidation current of 75 mA/mg and 365 mA/mg for DME and MF, respectively, highest among the studied Pt1Pd1Sn1/XC-72 and Pt1Pd1Sn1/CNT. The …

Show more

Mar 2022 • Energy Storage Materials

Double gas treatment: A successful approach for stabilizing the Li and Mn-rich NCM cathode materials’ electrochemical behavior

Sandipan Maiti, Hadar Sclar, Judith Grinblat, Michael Talianker, Maria Tkachev, Merav Tsubery, Xiaohan Wu, Malachi Noked, Boris Markovsky, Doron Aurbach

Herein, a systematic surface modification approach via double gas (SO2 and NH3) treatment at elevated temperatures is described, aimed to achieve a stable electrochemical performance of Li and Mn-rich NCM cathode materials of a typical composition 0.33Li2MnO3·0.67LiNi0.4Co0.2Mn0.4O2 (HE-NCM). Partial surface reduction of Mn4+ and the formation of a modified interface comprising Li-ions conductive nano-sized Li2SO4/Li2SO3 phases are established. Li-coin cells’ prolonged cycling performance demonstrated significantly improved capacity retention (∼2.2 times higher than untreated cathode materials) for the double-gas-treated cathodes after 400 cycles at a 1.0 C rate. Stable discharge potential and lower voltage hysteresis during cycling were also achieved through the double gas treatment. Comparative electrochemical studies in full-pouch cells [vs. Graphite anodes] also demonstrated considerably …

Show more

Mar 2022 • Materials

Effects of a ZnCuO-Nanocoated Ti-6Al-4V Surface on Bacterial and Host Cells

Kamal Dabbah, Ilana Perelshtein, Aharon Gedanken, Yael Houri-Haddad, Osnat Feuerstein

This study aims to investigate the effects of a novel ZnCuO nanoparticle coating for dental implants—versus those of conventional titanium surfaces—on bacteria and host cells. A multispecies biofilm composed of Streptococcus sanguinis, Actinomyces naeslundii, Porphyromonas gingivalis, and Fusobacterium nucleatum was grown for 14 days on various titanium discs: machined, sandblasted, sandblasted and acid-etched (SLA), ZnCuO-coated, and hydroxyapatite discs. Bacterial species were quantified with qPCR, and their viability was examined via confocal microscopy. Osteoblast-like and macrophage-like cells grown on the various discs for 48 h were examined for proliferation using an XTT assay, and for activity using ALP and TNF-α assays. The CSLM revealed more dead bacteria in biofilms grown on titanium than on hydroxyapatite, and less on sandblasted than on machined and ZnCuO-coated surfaces, with the latter showing a significant decrease in all four biofilm species. The osteoblast-like cells showed increased proliferation on all of the titanium surfaces, with higher activity on the ZnCuO-coated and sandblasted discs. The macrophage-like cells showed higher proliferation on the hydroxyapatite and sandblasted discs, and lower activity on the SLA and ZnCuO-coated discs. The ZnCuO-coated titanium has anti-biofilm characteristics with desired effects on host cells, thus representing a promising candidate in the complex battle against peri-implantitis.

Show more

Mar 2022 • Ultrafast Phenomena and Nanophotonics XXVI 11999, 75-81, 2022

Amplified correlated beams

Sara Meir, Moti Fridman

We spontaneously generated idler and signal beams with four-wave mixing process. Next, we measured with a time-lens their internal structure and found that the statistics of the different peaks and the separation between the peaks follow stochastic process. This is essential first step before checking the correlation between the beams and the entanglement of the generated photons.

Show more

Mar 2022 • Proceedings of the National Academy of Sciences

Light chaotic dynamics in the transformation from curved to flat surfaces

Chenni Xu, Itzhack Dana, Li-Gang Wang, Patrick Sebbah

Light propagation on a two-dimensional curved surface embedded in a three-dimensional space has attracted increasing attention as an analog model of four-dimensional curved spacetime in the laboratory. Despite recent developments in modern cosmology on the dynamics and evolution of the universe, investigation of nonlinear dynamics of light on non-Euclidean geometry is still scarce, with fundamental questions, such as the effect of curvature on deterministic chaos, challenging to address. Here, we study classical and wave chaotic dynamics on a family of surfaces of revolution by considering its equivalent conformally transformed flat billiard, with nonuniform distribution of the refractive index. We prove rigorously that these two systems share the same dynamics. By exploring the Poincaré surface of section, the Lyapunov exponent, and the statistics of eigenmodes and eigenfrequency spectrum in the …

Show more

Mar 2022 • Real-time Measurements, Rogue Phenomena, and Single-Shot Applications VII …, 2022

Simulating the polarization dynamics of ultrafast solitons

Avi Klein, Moti Fridman

We study the polarization dynamics of ultrafast solitons in mode-locked fiber lasers. We found that when a stable soliton is generated, its state-of-polarization shifts toward a stable state, and when the soliton is generated with excess power levels it experiences relaxation oscillations in its intensity and timing. On the other hand, when a soliton is generated in an unstable state-of-polarization, it either decays in intensity until it disappears, or its temporal width decreases until it explodes into several solitons, and then it disappears. All our results are supported by both experimental measurements and calculated results. For numerically modeling the dynamics of ultrafast solitons we resort to a non-Lagrangian approach for simulating coupled complex Ginzburg-Landau equations for the two components of the electric wave vector. Here we present the numerical code and results and explain in details how we obtained them.

Show more

Mar 2022 • PLoS pathogens

Experimental evolution links post-transcriptional regulation to Leishmania fitness gain

Laura Piel, K Shanmugha Rajan, Giovanni Bussotti, Hugo Varet, Rachel Legendre, Caroline Proux, Thibaut Douché, Quentin Giai-Gianetto, Thibault Chaze, Thomas Cokelaer, Barbora Vojtkova, Nadav Gordon-Bar, Tirza Doniger, Smadar Cohen-Chalamish, Praveenkumar Rengaraj, Céline Besse, Anne Boland, Jovana Sadlova, Jean-François Deleuze, Mariette Matondo, Ron Unger, Petr Volf, Shulamit Michaeli, Pascale Pescher, Gerald F Späth

The protozoan parasite Leishmania donovani causes fatal human visceral leishmaniasis in absence of treatment. Genome instability has been recognized as a driver in Leishmania fitness gain in response to environmental change or chemotherapy. How genome instability generates beneficial phenotypes despite potential deleterious gene dosage effects is unknown. Here we address this important open question applying experimental evolution and integrative systems approaches on parasites adapting to in vitro culture. Phenotypic analyses of parasites from early and late stages of culture adaptation revealed an important fitness tradeoff, with selection for accelerated growth in promastigote culture (fitness gain) impairing infectivity (fitness costs). Comparative genomics, transcriptomics and proteomics analyses revealed a complex regulatory network associated with parasite fitness gain, with genome instability causing highly reproducible, gene dosage-independent and -dependent changes. Reduction of flagellar transcripts and increase in coding and non-coding RNAs implicated in ribosomal biogenesis and protein translation were not correlated to dosage changes of the corresponding genes, revealing a gene dosage-independent, post-transcriptional mechanism of regulation. In contrast, abundance of gene products implicated in post-transcriptional regulation itself correlated to corresponding gene dosage changes. Thus, RNA abundance during parasite adaptation is controled by direct and indirect gene dosage changes. We correlated differential expression of small nucleolar RNAs (snoRNAs) with changes in rRNA modification …

Show more

Mar 2022 • Optical and Quantum Sensing and Precision Metrology II 12016, 233-238, 2022

Characterization of second-harmonic generation in silver nanoparticles for spontaneous parametric down-conversion

Ariel Ashkenazy, Eliahu Cohen, Dror Fixler

Energy-time entangled photon pairs (EPPs), which are at the heart of numerous quantum light applications, are commonly generated in nonlinear crystals. Some highly sensitive quantum applications require the use of ultra-broadband entangled photons that cannot be generated in nonlinear crystals due to phase-matching requirements. Here, we investigate the possibility of using metallic nanoparticles (MNPs) as a means for generating entangled photons through spontaneous parametric down-conversion (SPDC). MNPs are known for their strong light-matter coupling at their localized surface plasmon resonance, and since the propagation length through them is negligible relative to optical wavelengths, we consider them as excellent candidates to serve as non-phase matched sources of ultra-broadband entangled photons. To that end, we report experimental results of classical-light second-harmonic …

Show more

Mar 2022 • Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XIX …, 2022

Spectral ghost imaging with a speckle pattern

Shir Rabi, Moti Fridman

Mar 2022 • Real-time Measurements, Rogue Phenomena, and Single-Shot Applications VII …, 2022

Nonlinear aberrations in time lenses

Hamootal Duadi, Moti Fridman

We study the aberrations of four-wave mixing-based time-lenses resulting from the cross-phase modulations of the pump wave. These temporal aberrations have no spatial equivalent and are important when imaging weak signals with strong pump waves.In this work we show that as the pump power increases the cross-phase modulations of the pump are responsible for shifting, defocusing, and imposing temporal coma aberrations on the image.

Show more

Mar 2022 • Annual Review of Condensed Matter Physics 13, 385-405, 2022

Studying quantum materials with scanning SQUID microscopy

Eylon Persky, Ilya Sochnikov, Beena Kalisky

Electronic correlations give rise to fascinating macroscopic phenomena such as superconductivity, magnetism, and topological phases of matter. Although these phenomena manifest themselves macroscopically, fully understanding the underlying microscopic mechanisms often requires probing on multiple length scales. Spatial modulations on the mesoscopic scale are especially challenging to probe, owing to the limited range of suitable experimental techniques. Here, we review recent progress in scanning superconducting quantum interference device (SQUID) microscopy. We demonstrate how scanning SQUID combines unmatched magnetic field sensitivity and highly versatile designs, by surveying discoveries in unconventional superconductivity, exotic magnetism, topological states, and more. Finally, we discuss how SQUID microscopy can be further developed to answer the increasing demand for imaging …

Show more

Mar 2022 • Materials Today Energy

Ionically selective carbon nanotubes for hydrogen electrocatalysis in the hydrogen–bromine redox flow battery

Samuel S Hardisty, Kobby Saadi, Samala Nagaprasad Reddy, Ilya Grinberg, David Zitoun

Catalyst poisoning and leaching is a problem faced in almost all catalyst applications. A specific technology where catalyst poisoning and leaching are a major concern is the hydrogen bromine redox flow battery (H 2–B r 2 RFB), one of the most promising energy storage technologies. However, it is currently hindered through degradation of the hydrogen oxidation/evolution catalyst, caused by B r−/B r 3− which have crossed the membrane. To prevent this degradation, Pt nanoparticles were synthesized inside 2 nm single-walled carbon nanotubes (SWCNTs). Electrochemical and spectroscopic techniques show that the Pt@ SWCNT has a vastly improved stability and higher mass activity over a commercial 50% Pt/C catalyst. Density functional theory (DFT) calculations show that the stability results from the selective diffusion of H 2 and H+ over the B r− and B r 3− species through the SWCNT to the Pt catalyst …

Show more

Mar 2022 • Langmuir

Mussel-Inspired Polynorepinephrine/MXene-Based Magnetic Nanohybrid for Electromagnetic Interference Shielding in X-Band and Strain-Sensing Performance

Sayan Ganguly, Poushali Das, Arka Saha, Malachi Noked, Aharon Gedanken, Shlomo Margel

The current work delivers preparation of MXene-based magnetic nanohybrid coating for flexible electronic applications. Herein, we report carbon dot-triggered photopolymerized polynorepinepherene (PNE)-coated MXene and iron oxide hybrid deposited on the cellulose microporous membrane via a vacuum-assisted filtration strategy. The surface morphologies have been monitored by scanning electron microscopy analysis, and the coating thickness was evaluated by the gallium-ion-based focused ion beam method. Coated membranes have been tested against uniaxial tensile stretching and assessed by their fracture edges in order to assure flexibility and mechanical strength. Strain sensors and electromagnetic interference (EMI) shielding have both been tested on the material because of its electrical conductivity. The bending strain sensitivity has been stringent because of their fast ‘rupture and reform …

Show more

Mar 2022 • Optica

Quasi-static optical parametric amplification

Marc Jankowski, Nayara Jornod, Carsten Langrock, Boris Desiatov, Alireza Marandi, Marko Lončar, Martin M Fejer

Supplement 1 - A comprehensive theoretical treatment of quasi-static optical parametric amplification in the frequency domain, with an example waveguide design.

Show more


Powered by Articali