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Aug 2019 • ACS omega

Media characterization under scattering conditions by nanophotonics iterative multiplane spectroscopy measurements

I Yariv, C Shapira, H Duadi, D Fixler

Characterizing materials is preferably done by multiple wavelengths. In opaque materials, the scattering poses a challenge due to the additional complexity to the spectroscopic measurements. We have previously demonstrated an iterative multiplane method for characterizing materials using the reflection from turbid media. Initial studies were performed in the red wavelength regime (632.8 nm) which is optimal for biomedical applications. However, in order to differentiate between materials, it is better to use multiple wavelengths, as spectroscopy may detect the material fingerprint. In this paper, our iterative multiplane optical property extraction (IMOPE) technique is presented in the blue regime (473 nm). Agar-based solid phantom measurements were conducted and compared to our theoretical model. Compatibility between experiments in the red and blue wavelengths shows the robustness of our technique.

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Aug 2019 • 2007 Cleantech Conference and Trade Show Cleantech 2007, 322-325, 2019

Electrochemical ‘Lab on a chip’for Toxicity Detection in Water

Rachela Popovtzer, Tova Neufeld, Judith Rishpon, Yosi Shacham-Diamand

An electrochemical ‘Lab-on-a-chip’for water toxicity detection is presented. This miniaturized device containing an array of nano liter electrochemical cells, which integrates bacteria and can emulate physiological reactions in response to different chemicals. Bacteria, which have been genetically engineered to respond to environmental stress, act as a sensor element and trigger a sequence of processes, which leads to generation of electrical current.

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Aug 2019 • The journal of physical chemistry letters

Ultrafast charge carrier relaxation in inorganic halide perovskite single crystals probed by two-dimensional electronic spectroscopy

Xuan Trung Nguyen, Daniel Timmer, Yevgeny Rakita, David Cahen, Alexander Steinhoff, Frank Jahnke, Christoph Lienau, Antonietta De Sio

Halide perovskites are promising optoelectronic materials. Despite impressive device performance, especially in photovoltaics, the femtosecond dynamics of elementary optical excitations and their interactions are still debated. Here we combine ultrafast two-dimensional electronic spectroscopy (2DES) and semiconductor Bloch equations (SBEs) to probe the room-temperature dynamics of nonequilibrium excitations in CsPbBr3 crystals. Experimentally, we distinguish between excitonic and free-carrier transitions, extracting a ∼30 meV exciton binding energy, in agreement with our SBE calculations and with recent experimental studies. The 2DES dynamics indicate remarkably short, <30 fs carrier relaxation at a ∼3 meV/fs rate, much faster than previously anticipated for this material, but similar to that in direct band gap semiconductors such as GaAs. Dynamic screening of excitons by free carriers also develops on …

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Aug 2019 • Journal of Applied Toxicology

Cytotoxic and proinflammatory responses induced by ZnO nanoparticles in in vitro intestinal barrier

Graziano Colombo, Cristina Cortinovis, Elisa Moschini, Nicholas Bellitto, Maria Chiara Perego, Marco Albonico, Emanuela Astori, Isabella Dalle‐Donne, Alessia Bertero, Aharon Gedanken, Ilana Perelsthein, Paride Mantecca, Francesca Caloni

ZnO nanoparticles (NPs) are widely used nowadays, thus the gastrointestinal exposure to ZnO NPs is likely to be relevant and the effects on the intestinal barrier should be investigated. Polarized Caco‐2 cells were exposed from the apical (Ap) and basolateral (Bl) compartments to increasing concentrations (0, 10, 50 and 100 μg/mL) of sonochemical (sono) and commercial ZnO NPs. The transepithelial electrical resistance (TEER), cell viability, proinflammatory cytokine release and presence of protein oxidative damage were evaluated after exposure. TEER was not significantly affected by Ap exposure to either sono or commercial ZnO NPs at any tested concentrations. After Bl exposure to sono ZnO NPs (all the concentrations) and to 100 μg/mL of commercial ZnO NPs TEER was decreased (P < 0.05). Ap and Bl exposure to 100 μg/mL sono ZnO NPs and Ap exposure to 50 μg/mL commercial ZnO NPs induced a …

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Aug 2019 • ACS Applied Nano Materials

Biological logic gate using gold nanoparticles and fluorescence lifetime imaging microscopy

EA Barnoy, M Motiei, C Tzror, S Rahimipour, R Popovtzer, D Fixler

Current medicine could greatly improve by intelligent treatment systems able to respond autonomously to early stages of diseases from within a patient. As an initial study en route to such a system, we describe biologically relevant logic gates based on gold nanoparticles (GNPs) and fluorescent molecules that are able to respond to multiple input parameters so as to detect specific biological conditions all through the lens of fluorescence lifetime (FLT) imaging microscopy (FLIM). By conjugating the pH-responsive Oregon Green 488 (OG) to the GNPs by a trypsin-cleavable peptide, we manufactured GNP–OG constructs, which are responsive to two separate inputs: surrounding pH and proteinase presence. The GNP–OG constructs can sensitively detect and distinguish between conditions of low pH and no enzyme, the presence of one of either raised pH or enzyme, and the presence of both. Additionally, the GNP …

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Aug 2019 • Nucleic acids research

Pseudouridines on Trypanosoma brucei spliceosomal small nuclear RNAs and their implication for RNA and protein interactions

K Shanmugha Rajan, Tirza Doniger, Smadar Cohen-Chalamish, Dana Chen, Oz Semo, Saurav Aryal, Efrat Glick Saar, Vaibhav Chikne, Doron Gerber, Ron Unger, Christian Tschudi, Shulamit Michaeli

The parasite Trypanosoma brucei, the causative agent of sleeping sickness, cycles between an insect and a mammalian host. Here, we investigated the presence of pseudouridines (Ψs) on the spliceosomal small nuclear RNAs (snRNAs), which may enable growth at the very different temperatures characterizing the two hosts. To this end, we performed the first high-throughput mapping of spliceosomal snRNA Ψs by small RNA Ψ-seq. The analysis revealed 42 Ψs on T. brucei snRNAs, which is the highest number reported so far. We show that a trypanosome protein analogous to human protein WDR79, is essential for guiding Ψ on snRNAs but not on rRNAs. snoRNA species implicated in snRNA pseudouridylation were identified by a genome-wide approach based on ligation of RNAs following in vivo UV cross-linking. snRNA Ψs are guided by single hairpin snoRNAs, also implicated in rRNA modification …

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Aug 2019 • Diamond and Related Materials

Carbon nanotubes synthesis using siliceous breccia as a catalyst source

Arun Kumar, Yulia Kostikov, Marco Zanatta, Gian Domenico Sorarù, Beate Orberger, Gilbert Daniel Nessim, Gino Mariotto

In this work, siliceous breccia, a natural rock powder composed essentially of SiO2 α-quartz, has been employed directly as a catalyst without any chemical treatment for the synthesis of carbon nanotubes (CNTs) via chemical vapor deposition (CVD). In addition to quartz, it contains dispersed micro-inclusions of iron oxide-hydroxides, goethite or hematite, which act as catalysts to dissociate the hydrocarbon precursors and form carbon nanostructures. The catalytic performance of this powder was evaluated for C2H4 decomposition at 750 °C, with and without H2 flux. Thermal oxidation stability and carbon yield were measured by means of thermogravimetric analysis. Structural and vibrational characterization of the resulting material was carried out by environmental scanning electron microscopy (ESEM) and micro Raman spectroscopy. ESEM images show that the H2 addition affects the CNT diameter. We …

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Aug 2019 • Journal of Physics A: Mathematical and Theoretical

Running measurement protocol for the quantum first-detection problem

Dror Meidan, Eli Barkai, David A Kessler

The problem of the detection statistics of a quantum walker has received increasing interest. We investigate the effect of employing a moving detector, using a projective measurement approach with fixed sampling time, with the detector moving right before every detection attempt. For a tight-binding quantum walk on the line, the moving detector allows one to target a specific range of group velocities of the walker, qualitatively modifying the behavior of the quantum first-detection probabilities. We map the problem to that of a stationary detector with a modified unitary evolution operator and use established methods for the solution of that problem to study the first-detection statistics for a moving detector on a finite ring and on an infinite 1D lattice. On the line, the system exhibits a dynamical phase transition at a critical value of, from a state where the probability of detection decreases exponentially in time and the total …

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Aug 2019 • Optics letters

Supercontinuum generation in angle-etched diamond waveguides

Amirhassan Shams-Ansari, Pawel Latawiec, Yoshitomo Okawachi, Vivek Venkataraman, Mengjie Yu, Boris Desiatov, Haig Atikian, Gary L Harris, Nathalie Picqué, Alexander L Gaeta, Marko Lončar

We experimentally demonstrate on-chip supercontinuum generation in the visible region in angle-etched diamond waveguides. We measure an output spectrum spanning 670–920 nm in a 5-mm-long waveguide using 100-fs pulses with 187 pJ of incident pulse energy. Our fabrication technique, combined with diamond’s broad transparency window, offers a potential route toward broadband supercontinuum generation in the UV domain.

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Aug 2019 • Physical Review X

Quantum enhanced X-ray detection

S Sofer, E Strizhevsky, A Schori, K Tamasaku, S Shwartz

We present the first experimental demonstration of quantum enhanced detection at x-ray wavelengths. We show that x-ray pairs that are generated by spontaneous down-conversion can be used for the generation of heralded x-ray photons and directly measure the sub-Poissonian statistics of the single photons by using photon number resolving detectors. We utilize the properties of the strong time-energy correlations of the down-converted photons to demonstrate the ability to improve the visibility and the signal-to-noise ratio of an image with a small number of photons in an environment with a noise level that is higher than the signal by many orders of magnitude. A long-term goal of this work is to demonstrate x-ray photon entanglement. However, given the technical challenges, which are much greater than in the visible regime, we take a first step in demonstrating nonclassical (sub-Poisson) photon correlations. In …

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Aug 2019 • ACS omega

Sonochemical one-step synthesis of polymer-capped metal oxide nanocolloids: antibacterial activity and cytotoxicity

Anjani P Nagvenkar, Ilana Perelshtein, Ylenia Piunno, Paride Mantecca, Aharon Gedanken

Most antibacterial agents demand their action in the form of a liquid for compatibility and ease of use in biosystems, which are mainly composed of biological fluids. Controlling the colloidal stability of metal oxide nanocolloids, in parallel with minimizing the effect of using a large amount of surfactant on their biocidal activity and cytotoxicity, remains a challenge. Here, we address the stability of nanocolloids of ZnO and CuO in the presence of polymer surfactants and the influence of the surface capping on their antibacterial activity and cytotoxicity. The metal oxide nanoparticles (NPs) were synthesized sonochemically in a single step and tested against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus to validate their biocidal efficacy. Cytotoxicity studies were performed on human alveolar epithelial cells. Polyethylene glycol- and polyvinyl alcohol-capped NPs are observed to show the …

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Aug 2019 • ACS nano

Intranasal delivery of mesenchymal stem cell derived exosomes loaded with phosphatase and tensin homolog siRNA repairs complete spinal cord injury

Shaowei Guo, Nisim Perets, Oshra Betzer, Shahar Ben-Shaul, Anton Sheinin, Izhak Michaelevski, Rachela Popovtzer, Daniel Offen, Shulamit Levenberg

Individuals with spinal cord injury (SCI) usually suffer from permanent neurological deficits, while spontaneous recovery and therapeutic efficacy are limited. Here, we demonstrate that when given intranasally, exosomes derived from mesenchymal stem cells (MSC-Exo) could pass the blood brain barrier and migrate to the injured spinal cord area. Furthermore, MSC-Exo loaded with phosphatase and tensin homolog small interfering RNA (ExoPTEN) could attenuate the expression of PTEN in the injured spinal cord region following intranasal administrations. In addition, the loaded MSC-Exo considerably enhanced axonal growth and neovascularization, while reducing microgliosis and astrogliosis. The intranasal ExoPTEN therapy could also partly improve structural and electrophysiological function and, most importantly, significantly elicited functional recovery in rats with complete SCI. The results imply that …

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Aug 2019 • arXiv preprint arXiv:1908.01592

Sub-Attosecond Metrology via X-Ray Hong-Ou-Mandel Effect

S Volkovich, S Shwartz

We show that sub-attosecond delays and sub-Angstrom optical path differences can be measured by using Hong-Ou-Mandel interference measurements with x-rays. We propose to use a system comprising a source based on spontaneous parametric down-conversion for the generation of broadband x-ray photon pairs and a multilayer-based interferometer. The correlation time of the photon pairs and the Hong-Ou-Mandel dip are shorter than 1 attosecond, hence the precision of the measurements is expected to be better than 0.1 attosecond. We anticipate that the scheme we describe in this work will lead to the development of various techniques of quantum measurements with ultra-high precision at x-ray wavelengths.

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Aug 2019 • Scientific reports

non-invasive imaging through Scattering Medium by Using a Reverse Response Wavefront Shaping technique

Abhijit Sanjeev, Yuval Kapellner, Nadav Shabairou, Eran Gur, Moshe Sinvani, Zeev Zalevsky

Fundamental challenge of imaging through a scattering media has been resolved by various approaches in the past two decades. Optical wavefront shaping technique is one such method in which one shapes the wavefront of light entering a scattering media using a wavefront shaper such that it cancels the scattering effect. It has been the most effective technique in focusing light inside a scattering media. Unfortunately, most of these techniques require direct access to the scattering medium or need to know the scattering properties of the medium beforehand. Through the novel scheme presented on this paper, both the illumination module and the detection are on the same side of the inspected object and the imaging process is a real time fast converging operation. We model the scattering medium being a biological tissue as a matrix having mathematical properties matched to the physical and biological aspects …

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Aug 2019 • arXiv preprint arXiv:1908.02495

Evidence of fermion-to-boson crossover in the fermionic two-leg flux ladder

Marcello Calvanese Strinati, Richard Berkovits, Efrat Shimshoni

We study the crossover between fermions and bosons in a system of two coupled one-dimensional chains subjected to a gauge flux (two-leg flux ladder), with both attractive and repulsive interaction. In the presence of strong attractive nearest-neighbour interaction and repulsive next-to-nearest-neighbour 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 analyze such crossover in specific limits. 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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Aug 2019 • CCS Chemistry 1 (3), 239-250, 2019

Oxygen nanoshuttles for tumor oxygenation and enhanced cancer treatment

Liangzhu Feng, Oshra Betzer, Danlei Tao, Tamar Sadan, Rachela Popovtzer, Zhuang Liu

Tumor hypoxia is one of the hostile tumor microenvironment characteristics occurring in solid tumors. This feature is closely related to tumor progression and can negatively impair the effectiveness of cancer therapeutics. Recently, various strategies have been developed that enable efficient tumor oxygenation, not only enhancing treatment outcome of oxygen-consuming cancer therapeutics such as radiotherapy and photodynamic therapy, but also reversing the immunosuppressive tumor microenvironment to promote cancer immunotherapy. This review focuses on the latest progress in design and fabrication of innovative tumor-targeted oxygen nanoshuttles that attenuate tumor hypoxia and enhance cancer therapy. Future perspectives for clinical translation of tumor-targeted oxygen nanoshuttles will be further discussed.

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Aug 2019 • ACS Photonics

Graphene Schottky varactor diodes for high-performance photodetection

Adi Levi, Moshe Kirshner, Ofer Sinai, Eldad Peretz, Ohad Meshulam, Arnab Ghosh, Noam Gotlib, Chen Stern, Shaofan Yuan, Fengnian Xia, Doron Naveh

Over the past decade graphene devices have inspired the progress of future electronic and optoelectronic technologies. The unique combination of fast carrier dynamics and intrinsic quantum capacitance of graphene is a fertile ground for implementing novel device architectures. Here, we report on a novel device architecture comprising graphene Schottky diode varactors and assess the potential applications of this type of new device in optoelectronics. We show that graphene varactor diodes exhibit significant advantages compared with existing graphene photodetectors including elimination of high dark currents and enhancement of the external quantum efficiency (EQE). Our devices demonstrate a large photoconductive gain and EQE of up to 37%, fast photoresponse, and low leakage currents at room temperature.

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Aug 2019 • Frontiers in immunology

Exclusive temporal stimulation of IL-10 expression in LPS-stimulated mouse macrophages by cAMP inducers and type I interferons

Orna Ernst, Yifat Glucksam-Galnoy, Bibek Bhatta, Muhammad Athamna, Iris Ben-Dror, Yair Glick, Doron Gerber, Tsaffrir Zor

Expression of the key anti-inflammatory cytokine IL-10 in lipopolysaccharide (LPS)-stimulated macrophages is mediated by a delayed autocrine / paracrine loop of type I interferons (IFN) to ensure timely attenuation of inflammation. We have previously shown that cAMP synergizes with early IL-10 expression by LPS, but is unable to amplify the late type I IFN-dependent activity. We now examined the mechanism of this synergistic transcription in mouse macrophages at the promoter level, and explored the crosstalk between type I IFN signaling and cAMP, using the

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Aug 2019 • Microorganisms

The algal symbiont modifies the transcriptome of the Scleractinian coral Euphyllia paradivisa during heat stress

Dalit Meron, Keren Maor-Landaw, Eviatar Weizman, Hiba Waldman Ben-Asher, Gal Eyal, Ehud Banin, Yossi Loya, Oren Levy

The profound mutualistic symbiosis between corals and their endosymbiotic counterparts, Symbiodiniaceae algae, has been threatened by the increase in seawater temperatures, leading to breakdown of the symbiotic relationship—coral bleaching. To characterize the heat-stress response of the holobiont, we generated vital apo-symbiotic Euphyllia paradivisa corals that lacked the endosymbiotic algae. Using RNA sequencing, we analyzed the gene expression of these apo-symbionts vs. symbiotic ones, to test the effect of the algal presence on the tolerance of the coral. We utilized literature-derived lists of “symbiosis differentially expressed genes” and “coral heat-stress genes” in order to compare between the treatments. The symbiotic and apo-symbiotic samples were segregated into two separate groups with several different enriched gene ontologies. Our findings suggest that the presence of endosymbionts has a greater negative impact on the host than the environmental temperature conditions experienced by the holobiont. The peak of the stress reaction was identified as 28 C, with the highest number of differentially expressed genes. We suggest that the algal symbionts increase coral holobiont susceptibility to elevated temperatures. Currently, we can only speculate whether coral species, such as E. paradivisa, with the plasticity to also flourish as apo-symbionts, may have a greater chance to withstand the upcoming global climate change challenge. View Full-Text

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Aug 2019 • PloS one

Exploring the role of the various methionine residues in the Escherichia coli CusB adapter protein

Aviv Meir, Gulshan Walke, Fabian Schwerdtfeger, Lada Gevorkyan Airapetov, Sharon Ruthstein

The dissemination of resistant pathogenic microbes has become one of the most challenging problems that modern medicine has faced. Developing novel drugs based on new molecular targets that previously were not targeted, is therefore the highest priority in antibiotics research. One approach that has been recently suggested is to inhibit copper transporters in prokaryotic systems. Copper is required for many biological pathways, but sometimes it can harm the cell. Pathogenic systems have a highly sophisticated copper-regulation network; therefore, a better understanding of how this network operates at the molecular level should assist in developing the next generation of antibiotics. The CusB protein is part of the CusCBA periplasmic Cu(I) efflux system in Gram-negative bacteria, and was recently reported to play a key role in the functioning of the whole CusCBA system, in which conformational changes as well as the assembly/disassembly process control the opening of the transporter. More knowledge of the underlying mechanism is needed to attain a full understanding of CusB functioning, which is associated with targeting specific and crucial residues in CusB. Here, we combine in-vitro structural measurements, which use EPR spectroscopy and UV-Vis measurements, with cell experiments to explore the role of the various methionine residues in CusB. We targeted two methionine residues (M227 and M241) that are essential for the proper functioning of CusB.

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Aug 2019 • Journal of The Electrochemical Society

Stable LiNi0. 8Co0. 1Mn0. 1O2| Li metal cells with practical loading at 30 degrees C and elevated temperatures

Elena Markevich, Gregory Salitra, Y Talyosef, Doron Aurbach

We report on the highly stable lithium metal| LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811) cells with practical electrodes loading of 3.4 mAh cm− 2, low amount of electrolyte solution comprising 1M LiPF 6 in fluoroethylene carbonate (FEC)/dimethyl carbonate (DMC), around 1–1.5 μL mg− 1 of active cathode material (22–33 μL cm− 2) and current density of 1 mA cm− 2 both at 30 C and elevated temperatures (45–55 C). The NCM 811 cathodes and Li metal anodes were characterized by X-ray diffraction, SEM and Fourier transform infrared spectroscopy. We demonstrate that the cathodes' active mass preserves its crystal structure and particles morphology without any signs for cracks formation both after cycling with FEC and EC based electrolyte solutions. The limiting factor for stable cycling of Li| NCM 811 cells is the formation of thick resistive films on the surface of Li anodes which is highly dependent on the electrolyte …

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