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Dec 2019 • MRS Bulletin

There’sa lithium battery in your future

Rachel Berkowitz, Doron Aurbach

Battery technology has come a long way since September 1899, when Ferdinand Porsche’s electric powered car won its first road race. The “Egger-Lohner electric C.2 Phaeton” carried a Tudor brand lead-acid battery that weighed 500 kg and propelled the 1350-kg vehicle with 3 hp (2.2 kW for 3–5 h) for 80 km.

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Dec 2019 • Journal of biophotonics

Contact‐free endoscopic photoacoustic sensing using speckle analysis

Benjamin Lengenfelder, Fanuel Mehari, Martin Hohmann, Cita Löhr, Maximilian J Waldner, Michael Schmidt, Zeev Zalevsky, Florian Klämpfl

Photoacoustic endoscopy (PAE) is an emerging imaging modality, which offers a high imaging penetration and a high optical contrast in soft tissue. Most of the developed endoscopic photoacoustic sensing systems use miniaturized contact ultrasound transducers or complex optical approaches. In this work, a new fiber‐based detection technique using speckle analysis for contact‐free signal detection is presented. Phantom and ex vivo experiments are performed in transmission and reflection mode for proof of concept. In summary, the potential of the technique for endoscopic photoacoustic signal detection is demonstrated. The new technique might help in future to broaden the applications of PAE in imaging or guiding minimally invasive laser procedures.

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Dec 2019 • Cell reports

SIRT6 promotes hepatic beta-oxidation via activation of PPARα

Shoshana Naiman, Frank K Huynh, Reuven Gil, Yair Glick, Yael Shahar, Noga Touitou, Liat Nahum, Matan Y Avivi, Asael Roichman, Yariv Kanfi, Asaf A Gertler, Tirza Doniger, Olga R Ilkayeva, Ifat Abramovich, Orly Yaron, Batia Lerrer, Eyal Gottlieb, Robert A Harris, Doron Gerber, Matthew D Hirschey, Haim Y Cohen

The pro-longevity enzyme SIRT6 regulates various metabolic pathways. Gene expression analyses in SIRT6 heterozygotic mice identify significant decreases in PPARα signaling, known to regulate multiple metabolic pathways. SIRT6 binds PPARα and its response element within promoter regions and activates gene transcription. Sirt6+/− results in significantly reduced PPARα-induced β-oxidation and its metabolites and reduced alanine and lactate levels, while inducing pyruvate oxidation. Reciprocally, starved SIRT6 transgenic mice show increased pyruvate, acetylcarnitine, and glycerol levels and significantly induce β-oxidation genes in a PPARα-dependent manner. Furthermore, SIRT6 mediates PPARα inhibition of SREBP-dependent cholesterol and triglyceride synthesis. Mechanistically, SIRT6 binds PPARα coactivator NCOA2 and decreases liver NCOA2 K780 acetylation, which stimulates its activation of …

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Dec 2019 • Nanomaterials

Advanced Surface Probing Using a Dual-Mode NSOM–AFM Silicon-Based Photosensor

Matityahu Karelits, Emanuel Lozitsky, Avraham Chelly, Zeev Zalevsky, Avi Karsenty

A feasibility analysis is performed for the development and integration of a near-field scanning optical microscope (NSOM) tip–photodetector operating in the visible wavelength domain of an atomic force microscope (AFM) cantilever, involving simulation, processing, and measurement. The new tip–photodetector consists of a platinum–silicon truncated conical photodetector sharing a subwavelength aperture, and processing uses advanced nanotechnology tools on a commercial silicon cantilever. Such a combined device enables a dual-mode usage of both AFM and NSOM measurements when collecting the reflected light directly from the scanned surface, while having a more efficient light collection process. In addition to its quite simple fabrication process, it is demonstrated that the AFM tip on which the photodetector is processed remains operational (ie, the AFM imaging capability is not altered by the process). The AFM–NSOM capability of the processed tip is presented, and preliminary results show that AFM capability is not significantly affected and there is an improvement in surface characterization in the scanning proof of concept. View Full-Text

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Dec 2019 • Carbon

Abnormal electrochemical behavior of rounded graphite

Ortal Lavi, Ortal Haik, Daniel Hirshberg, Yosef Talyosef, Ella Zinigard, Boris Markovsky, Yulia Vestfrid, Yuval Elias, Doron Aurbach, Daniela Kovacheva

Round-shaped natural graphite is commonly used as anode material for rechargeable lithium-ion batteries. We report atypical electrochemical behavior of round-shaped graphite anodes in Li-ion batteries: an intriguing phenomenon whereby substantial progressive increase in capacity is observed over tens of cycles. To understand the reasons underlying this abnormal behavior, we investigated the surface and bulk structure properties using HRSEM, XRD and Raman spectroscopy. Graphite particles with tense structure undergo exfoliation and fracture due to multiple transformations in intercalation/deintercalation processes. The increased capacity may result from enhanced particle exfoliation, compared with non-rounded graphite, which is accompanied by appearance of graphene sheets and fracture.

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Dec 2019 • Journal of Low Temperature Physics

Niobium nitride thin films for very low temperature resistive thermometry

Tuyen Nguyen, Adib Tavakoli, Sebastien Triqueneaux, Rahul Swami, Aki Ruhtinas, Jeremy Gradel, Pablo Garcia-Campos, Klaus Hasselbach, Aviad Frydman, Benjamin Piot, Mathieu Gibert, Eddy Collin, Olivier Bourgeois

We investigate thin-film resistive thermometry based on metal-to-insulator transition (niobium nitride) materials down to very low temperature. The variation of the NbN thermometer resistance has been calibrated versus temperature and magnetic field. High sensitivity in temperature variation detection is demonstrated through efficient temperature coefficient of resistance. The nitrogen content of the niobium nitride thin films can be tuned to adjust the optimal working temperature range. In the present experiment, we show the versatility of the NbN thin-film technology through applications in very different low-temperature use cases. We demonstrate that thin-film resistive thermometry can be extended to temperatures below 30 mK with low electrical impedance.

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Dec 2019 • Nanomaterials

Antibacterial activity against methicillin-resistant staphylococcus aureus of colloidal polydopamine prepared by carbon dot stimulated polymerization of dopamine

Moorthy Maruthapandi, Michal Natan, Gila Jacobi, Ehud Banin, John HT Luong, Aharon Gedanken

A simple one-step process for the polymerization of dopamine has been developed using nitrogen-doped carbon dots ([email protected]–dots) as the sole initiator. The synthesized amorphous polydopamine (PDA)-doped [email protected]–dots (PDA–[email protected]–dots composite) exhibited a negative charge of–39 mV with particle sizes ranging from 200 to 1700 nm. The stable colloidal solution was active against methicillin-resistant Staphylococcus aureus (MRSA), a Gram-negative bacterium. The strong adhesion of the polymer to the bacterial membrane resulted in a limited diffusion of nutrients and wastes in and out of the cell cytosol, which is a generic mechanism to trigger cell death. Another possible route is the autoxidation of the catechol moiety of PDA to form quinone and release reactive oxygen species (ROS) such as superoxide radicle and hydrogen peroxide, two well-known ROS with antimicrobial properties against both Gram-negative and Gram-positive bacteria. View Full-Text

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Antibody repertoire sequencing and genomic DNA analysis reveal a large number of polymorphisms in the variable immunoglobulin genes

Ivana Mikocziova, Moriah Gidoni, Ida Lindeman, Omri Snir, Gur Yaari, Ludvig M Sollid

Dec 2019 • PloS one

Inhibiting the copper efflux system in microbes as a novel approach for developing antibiotics

Aviv Meir, Veronica Lepechkin-Zilbermintz, Shirin Kahremany, Fabian Schwerdtfeger, Lada Gevorkyan-Airapetov, Anna Munder, Olga Viskind, Arie Gruzman, Sharon Ruthstein

Five out of six people receive at least one antibiotic prescription per year. However, the ever-expanding use of antibiotics in medicine, agriculture, and food production has accelerated the evolution of antibiotic-resistant bacteria, which, in turn, made the development of novel antibiotics based on new molecular targets a priority in medicinal chemistry. One way of possibly combatting resistant bacterial infections is by inhibiting the copper transporters in prokaryotic cells. Copper is a key element within all living cells, but it can be toxic in excess. Both eukaryotic and prokaryotic cells have developed distinct copper regulation systems to prevent its toxicity. Therefore, selectively targeting the prokaryotic copper regulation system might be an initial step in developing next-generation antibiotics. One such system is the Gram-negative bacterial CusCFBA efflux system. CusB is a key protein in this system and was previously reported to play an important role in opening the channel for efflux via significant structural changes upon copper binding while also controlling the assembly and disassembly process of the entire channel. In this study, we aimed to develop novel peptide copper channel blockers, designed by in silico calculations based on the structure of CusB. Using a combination of magnetic resonance spectroscopy and various biochemical methods, we found a lead peptide that promotes copper-induced cell toxicity. Targeting copper transport in bacteria has not yet been pursued as an antibiotic mechanism of action. Thus, our study lays the foundation for discovering novel antibiotics.

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Dec 2019 • Journal of The Electrochemical Society

Corrosion resistance and acidic ORR activity of Pt-based catalysts supported on nanocrystalline alloys of molybdenum and tantalum carbide

Eliran R Hamo, Polina Tereshchuk, Melina Zysler, David Zitoun, Amir Natan, Brian A Rosen

Cathode catalysts in polymer electrolyte membrane fuel cells (PEMFCs) are often supported by carbon, which is susceptible to corrosion at operating potentials. Transition metal carbides (TMCs) are a class of material that could be used as catalyst supports to replace carbon as they are electrically conductive and can be resistant to corrosion. TMCs which show promising activity for the oxygen reduction reaction (ORR) have been shown to suffer from oxidation and dissolution, whereas corrosion-resistant carbides tend to have significantly lower ORR activities. Here we used co-reduction carburization to synthesized alloys of Mo 2 C and TaC with the aim of designing a carbide support that was both active and corrosion resistant. The addition of 15 mol% Ta to the precursor mixture used to synthesize the alloy support increased the corrosion potential by nearly 150 mV and decreased the corrosion current to 16% of …

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Dec 2019 • Emerging Photovoltaic Technologies: Photophysics and Devices, 209-250, 2019

Quantum Dot–Sensitized Solar Cells

Huifang Geng, Kaibo Zheng

The only difference between Dot–Sensitized Solar Cells (DSSCs) and Quantum DSSCs (QDSSC) is that the organic dye as photosensitizer is substituted by inorganic nanoparticle quantum dots. The electrolyte or hole transport material is used to transfer charges between photoanode and counter electrode. Counter electrode role is to transfer electrons from the external circuit to electrolyte and catalyzing the reduction reaction of electrolyte. A typical counter electrode is built on a conducting substrate with a layer of catalytic material. Photoanode is core part of a QDSSC, which is responsible for light absorption, generation of electron–hole pairs, and charge carrier transport. The mesoporous mesoporous metal oxide semiconductor film (MOS) plays two crucial roles in determining the performance of a cell device. Some popular methods in fabricating Titanium oxide molecule film include doctor blading, screen …

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Dec 2019

Rn and CO2 in Depth, as a Proxy for Pre-Seismic Activity

Hovav Zafrir, Elad Levintal, Uri Malik, Noam Weisbrod, Yochai Ben Horin, Zeev Zalevsky Zalevsky, Nimrod Inbar

Rn and CO2 in-depth, as a proxy for pre-seismic activity Hovav Zafrir1,4, Uri Malik1, Elad Levintal2, Noam Weisbrod2, Yochai Ben Horin3, Zeev Zalevsky4, Nimrod Inbar5 1Geological Survey of Israel, 32 Yesha'ayahu Leibowitz, Jerusalem 9371234, Israel, 2The Zuckerberg Institute for Water Research, Ben-Gurion University, 8499000 Sede Boqer, Israel, 3Soreq Nuclear Research Center, Yavne 81800, Israel, 4Faculty of Engineering, Bar Ilan University, Ramat-Gan 52900, Israel, 5Ariel University, Ariel 40700, Israel. (First author e-mail:; Abstract The method of long-term monitoring of subsurface gases in shallow to deep boreholes assumes that the climatic influence on geo-physicochemical parameters is limited since its energy decreases with the increase in the thickness of the geological cover. Hence, the monitoring of radon (Rn), CO2 and other constituents above and …

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Dec 2019


Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) 2016-05-16

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Dec 2019 • Physical Review B

Emergent bosons in the fermionic two-leg flux ladder

Marcello Calvanese Strinati, Richard Berkovits, Efrat Shimshoni

We study the emergence of bosonic pairs in a system of two coupled one-dimensional fermionic chains subject to a gauge flux (two-leg flux ladder), with both attractive and repulsive interaction. In the presence of strong attractive nearest-neighbor interaction and repulsive next-to-nearest-neighbor interaction, the system crosses into a regime in which fermions form tightly bound pairs, which behave as bosonic entities. By means of numerical simulations based on the density-matrix-renormalization-group (DMRG) method, we show in particular that in the strongly paired regime, the gauge flux induces a quantum phase transition of the Ising type from vortex density wave (VDW) to a charge density wave (CDW), characteristic of bosonic systems.

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Dec 2019 • Journal of biomedical optics

Corneal thickness measurement by secondary speckle tracking and image processing using machine-learning algorithms

Aviya Bennett, Elnatan Davidovitch, Yafim Beiderman, Sergey Agdarov, Yevgeny Beiderman, Avital Moshkovitz, Uri Polat, Zeev Zalevsky

Corneal thickness (CoT) is an important tool in the evaluation process for several disorders and in the assessment of intraocular pressure. We present a method enabling high-precision measurement of CoT based on secondary speckle tracking and processing of the information by machine-learning (ML) algorithms. The proposed configuration includes capturing by fast camera the laser beam speckle patterns backscattered from the corneal–scleral border, followed by ML processing of the image. The technique was tested on a series of phantoms having different thicknesses as well as in clinical trials on human eyes. The results show high accuracy in determination of eye CoT, and implementation is speedy in comparison with other known measurement methods.

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Dec 2019 • Nature communications

Observation of strong nonlinear interactions in parametric down-conversion of X-rays into ultraviolet radiation

S Sofer, O Sefi, Edward Strizhevsky, H Aknin, SP Collins, G Nisbet, B Detlefs, Ch J Sahle, S Shwartz

Nonlinear interactions between X-rays and long wavelength radiation can be used as a powerful atomic-scale probe for light-matter interactions and for properties of valence electrons. However, reported X-ray nonlinear effects were small and their observations required tremendous efforts. Here we report the observation of strong nonlinearities in parametric down-conversion (PDC) of X-rays to long wavelength radiation in gallium arsenide and lithium niobate crystals, with efficiencies about 4 orders of magnitude stronger than the efficiencies measured in any material studied before. Furthermore, we show that the efficiency in the ferroelectric phase of strontium barium niobite is two orders of magnitude stronger than in its paraelectric phase. This observation suggests that the lack of inversion symmetry is the origin for the strong observed nonlinearity. Additionally, we demonstrate the ability to use the effect for the …

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Dec 2019 • Angewandte Chemie International Edition

Heat‐Treated Aerogel as a Catalyst for Oxygen Reduction Reaction

Noam Zion, David A Cullen, Piotr Zelenay, Lior Elbaz

Aerogels are fascinating materials that can be used for a wide range of applications, one of which is electrocatalysis of the important oxygen reduction reaction. In their inorganic form, aerogels can have ultrahigh catalytic site density, high surface area, and tunable physical properties and chemical structures—important features in heterogeneous catalysis. Herein, we report on the synthesis and electrocatalytic properties of an iron–porphyrin aerogel. 5,10,15,20‐(Tetra‐4‐aminophenyl)porphyrin (H2TAPP) and FeII were used as building blocks of the aerogel, which was later heat‐treated at 600 °C to enhance electronic conductivity and catalytic activity, while preserving its macrostructure. The resulting material has a very high concentration of atomically dispersed catalytic sites (9.7×1020 sites g−1) capable of catalyzing the oxygen reduction reaction in alkaline solution (Eonset=0.92 V vs. RHE, TOF=0.25 e …

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Dec 2019 • Physical Review Research

Transport in disordered systems: the single big jump approach

Wanli Wang, Alessandro Vezzani, Raffaella Burioni, Eli Barkai

In a growing number of strongly disordered and dense systems, the dynamics of a particle pulled by an external force field exhibits superdiffusion. In the context of glass-forming systems, supercooled glasses, and contamination spreading in porous media, it was suggested that this behavior be modeled with a biased continuous-time random walk. Here we analyze the plume of particles lagging far behind the mean, with the single big jump principle. Revealing the mechanism of the anomaly, we show how a single trapping time, the largest one, is responsible for the rare fluctuations in the system. These nontypical fluctuations still control the behavior of the mean square displacement, which is the most basic quantifier of the dynamics in many experimental setups. We show how the initial conditions, describing either the stationary state or nonequilibrium case, persist forever in the sense that the rare fluctuations are …

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Dec 2019 • Journal of nanobiotechnology

In vivo MRI assessment of bioactive magnetic iron oxide/human serum albumin nanoparticle delivery into the posterior segment of the eye in a rat model of retinal degeneration

Adi Tzameret, Hadas Ketter-Katz, Victoria Edelshtain, Ifat Sher, Enav Corem-Salkmon, Itay Levy, David Last, David Guez, Yael Mardor, Shlomo Margel, Ygal Rotenstrich

Retinal degeneration diseases affect millions of patients worldwide and lead to incurable vision loss. These diseases are caused by pathologies in the retina and underlying choroid, located in the back of the eye. One of the major challenges in the development of treatments for these blinding diseases is the safe and efficient delivery of therapeutics into the back of the eye. Previous studies demonstrated that narrow size distribution core–shell near infra-red fluorescent iron oxide (IO) nanoparticles (NPs) coated with human serum albumin (HSA, IO/HSA NPs) increase the half-life of conjugated therapeutic factors, suggesting they may be used for sustained release of therapeutics. In the present study, the in vivo tracking by MRI and the long term safety of IO/HSA NPs delivery into the suprachoroid of a rat model of retinal degeneration were assessed. Twenty-five Royal College of Surgeons (RCS) pigmented rats …

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Dec 2019 • Frontiers in plant science

Spectroscopic discrimination of sorghum silica phytoliths

Victor MR Zancajo, Sabrina Diehn, Nurit Filiba, Gil Goobes, Janina Kneipp, Rivka Elbaum

Grasses accumulate silicon in the form of silicic acid, which is precipitated as amorphous silica in microscopic particles termed phytoliths. These particles comprise a variety of morphologies according to the cell type in which the silica was deposited. Despite the evident morphological differences, phytolith chemistry has mostly been analysed in bulk samples, neglecting differences between the varied types formed in the same species. In this work we extracted leaf phytoliths from mature plants of Sorghum bicolor (L.) Moench. Using solid state NMR and thermogravimetric analysis we show that the extraction methods alter greatly the silica molecular structure, its condensation degree and the trapped organic matter. Measurements of individual phytoliths by Raman and synchrotron FTIR microspectroscopies in combination with multivariate analysis separated bilobate silica cells from prickles and long cells, based on the silica molecular structures and the fraction and composition of occluded organic matter. The variations in structure and composition of sorghum phytoliths suggest that the biological pathways leading to silica deposition vary between these cell types.

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Dec 2019 • Scientific reports

Switching of multi-state magnetic structures via domain wall propagation triggered by spin-orbit torques

Shubhankar Das, Ariel Zaig, Hariharan Nhalil, Liran Avraham, Moty Schultz, Lior Klein

Spin-orbit torques emerge as a promising method for manipulating magnetic configurations of spintronic devices. Here, we show that these torques can induce a magnetization reversal via domain wall propagation which may open new ways in developing novel spintronic devices and in particular in realizing high-density multi-level magnetic memory. Our devices are bi-layer heterostructures of Ni 0.8 Fe 0.2 on top of β-Ta patterned in the form of two or three crossing ellipses which exhibit in the crossing area shape-induced biaxial and triaxial magnetic anisotropy, respectively. We demonstrate field-free switching between discrete remanent magnetic states of the structures by spin-orbit torques induced by flowing electrical current through one of the ellipses. We note switchings induced by the coupling between the ellipses where current flowing in one ellipse triggers a reversal in a neighboring ellipse which …

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