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Mar 2019 • Experimental eye research

An optimized protocol for generating labeled and transplantable photoreceptor precursors from human embryonic stem cells

Amos Markus, Astar Shamul, Yoav Chemla, Nairouz Farah, Lital Shaham, Ronald S Goldstein, Yossi Mandel

Cell replacement therapy is a promising approach for treatment of retinal degenerative diseases. Several protocols for the generation of photoreceptor precursors (PRP) from human embryonic stem cells (hESC) have been reported with variable efficiency. Herein, we show the advantages of use of size-controlled embryoid bodies in the ESC differentiation process using two differentiation protocols. We further explored cell-labeling methods for following the survival of PRP transplanted subretinally in rat eyes. Size-controlled embryoid bodies (EBs) generated using microwell dishes and non-size-controlled EBs generated using V-shaped 96-well plates were differentiated into PRP using two differentiation protocols. The differentiation protocols utilized two different combinations of growth factors. The first, Dkk1, Noggin, and IGF1, and the second protocol used IWR1e, SAG, and CHIR99021. Differentiation efficiency to …

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Mar 2019 • Chemical reviews 119 (5), 3349-3417, 2019

Halide perovskites: is it all about the interfaces?

Philip Schulz, David Cahen, Antoine Kahn

Design and modification of interfaces, always a critical issue for semiconductor devices, has become a primary tool to harness the full potential of halide perovskite (HaP)-based optoelectronics, including photovoltaics and light-emitting diodes. In particular, the outstanding improvements in HaP solar cell performance and stability can be primarily ascribed to a careful choice of the interfacial layout in the layer stack. In this review, we describe the unique challenges and opportunities of these approaches (section 1). For this purpose, we first elucidate the basic physical and chemical properties of the exposed HaP thin film and crystal surfaces, including topics such as surface termination, surface reactivity, and electronic structure (section 2). This is followed by discussing experimental results on the energetic alignment processes at the interfaces between the HaP and transport and buffer layers. This section includes …

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Mar 2019 • International Society for Optics and Photonics

Plasma dispersion effect based super-resolved imaging in silicon

Maor Tiferet, Hadar Pinhas, Omer Wagner, Yossef Danan, Meir Danino, Zeev Zalevsky, Moshe Sinvani

In this paper we present a new method for shaping of a pulsed IR (λ=1550 nm) laser beam in silicon. The shaping is based on plasma dispersion effect (PDE). The shaping is done by a second pulsed pump laser beam at 532 nm which simultaneously and collinearly illuminates the silicon’s surface with the IR beam. Following the PDE, and in proportion to its spatial intensity distribution, the 532 nm laser beam shapes the point spread function (PSF) by controlling the lateral transmission of the IR probe beam. The use of this probe in laser scanning microscope allows imaging and wide range of contactless electrical measurements in silicon integrated circuits (IC) being under operation e.g. for failure analysis purposes. We propose this shaping method to overcome the diffraction resolution limit in silicon microscopy on and deep under the silicon surface depending on the wavelength of the pump laser and its temporal …

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Mar 2019 • Neural Imaging and Sensing 2019 10865, 87-98, 2019

A leech brain in the dish: a method for detailed analysis of specifically labeled single cells

Sharon Cohen, Koby Baranes, Orit Shefi

One of the major goals in neuroscience is to identify the enormous diversity of neurons, depict their heterogeneity, and explore their function under normal and pathological conditions. To date, the repetitive study of specific neurons in the vertebrate nervous system is almost impossible. Invertebrate nervous systems, on the other hand, have provided an opportunity to study single identified neurons for decades. However, simple methods to study the identified neurons in cell culture are still lacking. In this research study we developed a simple method, based on microinjection, to study and manipulate single identified neurons in culture. The concept behind this method is to utilize the advantages and simplicity of the leech nervous system. Within the leech ganglion, neurons are arranged in a characteristic and stereotypical manner. Their location, size, and biophysical properties are highly characterized. This allows …

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Mar 2019 • arXiv preprint arXiv:1903.02824

Multiple fourier component analysis of x-ray second harmonic generation in diamond

P Chakraborti, B Senfftleben, B Kettle, SW Teitelbaum, PH Bucksbaum, S Ghimire, JB Hastings, H Liu, S Nelson, T Sato, S Shwartz, Y Sun, C Weninger, D Zhu, DA Reis, M Fuchs

The unprecedented brilliance of X-ray free-electron lasers (XFELs) [1, 2] has enabled first studies of nonlinear interactions in the hard X-ray range. In particular, X-ray-optical mixing [3], X-ray second harmonic generation (XSHG) [4] and nonlinear Compton scattering (NLCS) [5] have been recently observed for the first time using XFELs. The former two experiments as well as X-ray parametric downconversion (XPDC)[6, 7] are well explained by nonlinearities in the impulse approximation[8], where electrons in a solid target are assumed to be quasi free for X-ray interactions far from atomic resonances. However, the energy of the photons generated in NLCS at intensities reaching up to 4 x 1020 W/cm2 exhibit an anomalous red-shift that is in violation with the free-electron model. Here we investigate the underlying physics of X-ray nonlinear interactions at intensities on order of 1016 W/cm2. Specifically, we perform a systematic study of XSHG in diamond. While one phase-matching geometry has been measured in Shwartz et al.[4], we extend these studies to multiple Fourier components and with significantly higher statistics, which allows us to determine the second order nonlinear structure factor. We measure the efficiency, angular dependence, and contributions from different source terms of the process. We find good agreement of our measurements with the quasi-free electron model.

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Mar 2019 • FlatChem 14, 100084, 2019

Irradiation-induced metal-insulator transition in monolayer graphene

I Shlimak, E Zion, A Butenko, Yu Kaganovskii, V Richter, A Sharoni, E Kogan, M Kaveh

A brief review of experiments directed to study a gradual localization of charge carriers and metal-insulator transition in samples of disordered monolayer graphene is presented. Disorder was induced by irradiation with different doses of heavy and light ions. Degree of disorder was controlled by measurements of the Raman scattering spectra. The temperature dependences of conductivity and magnetoresistance (MR) showed that at low disorder, conductivity is governed by the weak localization and antilocalization regime. Further increase of disorder leads to strong localization of charge carriers, when the conductivity is described by the variable-range-hopping (VRH) mechanism. It was observed that MR in the VRH regime is negative in perpendicular fields and is positive in parallel magnetic fields which allowed to reveal different mechanisms of hopping MR. Theoretical analysis is in a good agreement with …

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Mar 2019 • ChemCatChem

Ultrafine ruthenium oxide nanoparticles supported on molybdenum oxide nanosheets as highly efficient electrocatalyst for hydrogen evolution in acidic medium

Hari Krishna Sadhanala, Villa Krishna Harika, Tirupathi Rao Penki, Doron Aurbach, Aharon Gedanken

Notably, compared to MoO3 or RuO2, the composite exhibited high exchange current density of 0.57 mAcmÀ 2, and a current density of 10 mAcmÀ 2 was achieved at low overpotential of 110mV in 0.5 MH2so4. The Tafel slope of the MoO3@ RuO2 catalyst was 62 mVdecÀ 1 and it showed excellent stability. This remarkable performance can be attributed to the synergetic effect generated by the strong interaction between MoO3 nanosheets and RuO2 nanoparticles, which resulted in enhanced long-term stability as well.

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Mar 2019 • Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XVI …, 2019

Insulin-coated gold nanoparticles as an effective approach for bypassing the blood-brain barrier

Oshra Betzer, Malka Shilo, Menachem Motiei, Rachela Popovtzer

A major challenge for treatment of neurodegenerative disorders is the need to overcome the restrictive mechanism of the blood-brain-barrier (BBB) for delivery of therapeutic agents into the brain. Our goal was to develop an efficient nanoparticle-based system with the ability to bypass the BBB by targeting insulin receptors. We demonstrate that insulincoated gold-nanoparticles (INS-GNPs) can serve as an effective endogenous BBB transport system for delivering therapeutics into the brain. We further conducted a quantitative in-vivo investigation of the effect of nanoparticle size (20, 50 and 70nm) on the ability of INS-GNPs to cross the BBB. The most widespread bio-distribution and highest accumulation within the brain (5% of the injected dose) was observed using 20nm INS-GNPs, two hours post-injection. In-vivo CT imaging revealed that particles migrated to specific brain regions, rich in insulin receptors, which …

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Mar 2019 • Journal of the American Chemical Society

Discovering monoterpene catalysis inside nanocapsules with multiscale modeling and experiments

Efrat Pahima, Qi Zhang, Konrad Tiefenbacher, Dan T Major

Large-scale production of natural products, such as terpenes, presents a significant scientific and technological challenge. One promising approach to tackle this problem is chemical synthesis inside nanocapsules, although enzyme-like control of such chemistry has not yet been achieved. In order to better understand the complex chemistry inside nanocapsules, we design a multiscale nanoreactor simulation approach. The nanoreactor simulation protocol consists of hybrid quantum mechanics–molecular mechanics-based high temperature Langevin molecular dynamics simulations. Using this approach we model the tail-to-head formation of monoterpenes inside a resorcin[4]arene-based capsule (capsule I). We provide a rationale for the experimentally observed kinetics of monoterpene product formation and product distribution using capsule I, and we explain why additional stable monoterpenes, like camphene …

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Mar 2019 • The Journal of infectious diseases

Highly sensitive and specific Zika virus serological assays using a magnetic modulation biosensing system

Yehudit Michelson, Yaniv Lustig, Shira Avivi, Eli Schwartz, Amos Danielli

BackgroundZika virus has created global alarm because it has been associated with catastrophic fetal abnormalities, including microcephaly, spontaneous abortion, and intrauterine growth restriction. Current serological assays that detect antiviral antibodies suffer from low sensitivity and high cross-reactivity among different flaviviruses.MethodsIn this study, utilizing a novel magnetic modulation biosensing (MMB) system and the Zika nonstructural 1 protein, we show highly sensitive and specific Zika serological assays. We blindly tested 60 reverse-transcription polymerase chain reaction Zika-positive samples and healthy patients’ serum samples, as well as 44 serum samples from enzyme-linked immunosorbent assay (ELISA) West Nile- and dengue-positive patients. The Zika-positive samples were collected from Israeli travelers returning from Zika-endemic areas …

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Mar 2019 • Chemistry Letters

Trimodal nanoparticle contrast agent for ct, mri and spect imaging: Synthesis and characterization of radiolabeled core/shell iron oxide@ gold nanoparticles

Menachem Motiei, Tamar Dreifuss, Tamar Sadan, Noam Omer, Tamar Blumenfeld-Katzir, Eirini Fragogeorgi, George Loudos, Rachela Popovtzer, Noam Ben-Eliezer

Recently, nanoparticles have emerged as promising contrast agents for various imaging applications. In this paper, we present the synthesis and characterization of a novel hybrid nano-structure, consisting of an iron oxide@gold nanoparticle, labeled with technetium-99m, for trimodal SPECT/CT/MRI imaging. The particles showed efficient capabilities as CT/MRI imaging agent and high radiochemical yield, indicating a potential single hybrid material for multimodal SPECT/CT/MRI.

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Mar 2019 • Carbon

Imidazole decorated reduced graphene oxide: A biomimetic ligand for selective oxygen reduction electrocatalysis with Metalloporphyrins

Rifael Z Snitkoff, Naomi Levy, Inbal Ozery, Sharon Ruthstein, Lior Elbaz

We propose herein a bio-mimetic catalytic structure as a new approach to increase the oxygen reduction catalytic selectivity of transition metal complexes. As in biological systems, where there is a series of mediators between the active site and the surface, that lowers the activation energy of the overall reaction and increases its selectivity, we use here a structure where a molecular catalyst Fe(III)tetrakis(1-methyl-4-pyridyl) porphyrin is bonded to a surface via a benzimidazole mediator. Using electron paramagnetic resonance (EPR), UV–vis spectroscopy and electrochemical measurements, we compared the ORR activity of the molecular catalyst with and without benzimidazole and show that this ligand strongly influences the selectivity of the reaction and shifts it from the 2 to the 2+2-electron reduction.

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Mar 2019 • Nucleic acids research

Small nucleolar RNAs controlling rRNA processing in Trypanosoma brucei

Vaibhav Chikne, K Shanmugha Rajan, Moran Shalev-Benami, Kathryn Decker, Smadar Cohen-Chalamish, Hava Madmoni, Viplov K Biswas, Sachin Kumar Gupta, Tirza Doniger, Ron Unger, Christian Tschudi, Elisabetta Ullu, Shulamit Michaeli

In trypanosomes, in contrast to most eukaryotes, the large subunit (LSU) ribosomal RNA is fragmented into two large and four small ribosomal RNAs (srRNAs) pieces, and this additional processing likely requires trypanosome-specific factors. Here, we examined the role of 10 abundant small nucleolar RNAs (snoRNAs) involved in rRNA processing. We show that each snoRNA involved in LSU processing associates with factors engaged in either early or late biogenesis steps. Five of these snoRNAs interact with the intervening sequences of rRNA precursor, whereas the others only guide rRNA modifications. The function of the snoRNAs was explored by silencing snoRNAs. The data suggest that the LSU rRNA processing events do not correspond to the order of rRNA transcription, and that srRNAs 2, 4 and 6 which are part of LSU are processed before srRNA1. Interestingly, the 6 snoRNAs that affect srRNA1 …

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Mar 2019 • Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XVI …, 2019

An optical method to detect tissue scattering: theory, experiments and biomedical applications

I Yariv, H Duadi, D Fixler

In vivo physiological sensing is typically done either by imaging thin tissues or by examining changes in the attenuation coefficient. One known technique for thin tissue in vivo applications is the optical coherence tomography (OCT). However, deep tissue methods are usually based on diffusion reflection (DR), which correlates the optical properties to the reflected light intensity. The attenuation coefficient is composed of tissue absorption and scattering. We present a noninvasive nanophotonics technique, the iterative multi-plane optical property extraction (IMOPE) for extracting the scattering properties from a turbid medium. The reflectance-based IMOPE is most relevant for in vivo applications, hence, in this research we suggest a new theoretical description of phase accumulation in deep tissue, which is rarely mentioned in the literature, using a modified DR theory that represents the phase based on the effective …

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Mar 2019 • Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XVI …, 2019

The scattering of gold nanorods in identification of macrophages

R Chakraborty, D Leshem-Lev, D Fixler

Currently, gold nanorods (GNRs), with versatile optical behaviors, are in the immense study to achieve a variety of applications in the fields of diagnostics and therapy. Macrophages, the proficient phagocytic immune cells, mainly differentiated from monocytes, play a major role in our innate immunity. Depending on the state of a disease, an enhancement of local macrophage population occurs as a normal protective measure of our body. We want to monitor this increased level and use it as a prediction index of a disease. The advantage of working with macrophages is that they willingly internalize GNRs by phagocytosis. Now, the macrophages with GNRs can be identified by Flow Cytometric technique through the high scattering of GNRs. Moreover, the surface charge of GNRs can significantly change the uptake and cytotoxicity pattern of GNRs. Here we compared the uptake of GNRs, with different zeta potentials …

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Mar 2019 • JOSA B

Difference frequency generation of ultraviolet from X-ray pulses in opaque materials

Eviatar Minerbi, S Shwartz

We suggest a new approach for observing x-ray nonlinear wave mixing in opaque materials. We focus on difference frequency generation of ultraviolet radiation from two short x-ray pulses by measuring the depletion of the pumping pulses. Like other processes involving nonlinear interactions between x-rays and longer wavelengths, our method can lead to the development of a probe for spectroscopy of valence electrons at the atomic scale resolution. The two main advantages of the method we propose over the direct observation of the generated signal are the ability to probe the properties of materials at wavelengths where they are opaque and the higher predicted efficiency in the ultraviolet regime. We describe a possible experimental setup with realistic specifications optimized with respect to the characteristics of the input pulses. We expect that experimental observations of the effect will be feasible with the …

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Mar 2019 • Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XVI …, 2019

Frequency domain analysis of time-resolved fluorescence measurements using the squared distance approach

G Yahav, HH Diamandi, E Preter, D Fixler

Frequency domain analysis of time-resolved fluorescence measurements (TRFM) is an extremely rapid technique for medical diagnostics thanks to its unique sensitivity to a wide variety of physical and chemical features. Nevertheless, the determination of the underlying fluorescence lifetime (FLT) data of samples by their frequency response data (FRD), demands fitting algorithms. Therefore, the interpretation of the precise changes in the FLT of complex environments in term of biochemical processes is a challenge as it involves uncertainties associated with the chosen fitting algorithm. This research suggests a novel characterization procedure based on the squared distance (D2) between the FRD of the samples that avoid the inherent blurring caused by the transformation of the FRD into FLT data. The D2 approach was validated through simulated data of 6 classes with similar FLT characteristics, where the …

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Mar 2019 • Angewandte Chemie

Innentitelbild: EPR Spectroscopy Detects Various Active State Conformations of the Transcriptional Regulator CueR (Angew. Chem. 10/2019)

Hila Sameach, Shreya Ghosh, Lada Gevorkyan‐Airapetov, Sunil Saxena, Sharon Ruthstein

Cu II-NTA-Spinmarkierung des Transkriptionsregulators CueR, eines Kupfer erkennenden Proteins aus E. coli, ermöglichte die hochaufgelöste Detektion seiner verschiedenen Konformationszustände, wie S. Ruthstein et al. in ihrer Zuschrift auf S. 3085 demonstrieren. Zwei der Zustände, Aktivator 1 und 2, repräsentieren CueR in seiner Bindung an DNA und Cu I-Ionen. Aus den berechneten Strukturen lässt sich schließen, dass einer der beiden Zustände an der DNA stärker komprimiert ist und der Übergang zwischen den beiden Zuständen von der Cu I-Konzentration in der Bakterienzelle abhängt.

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Mar 2019 • Optical, Opto-Atomic, and Entanglement-Enhanced Precision Metrology 10934 …, 2019

Stimulated phononic oscillators in multi-core fibers (Conference Presentation)

Hilel Hagai Diamandi, Yosef London, Gil Bashan, Arik Bergman, Avinoam Zadok

SPIE Digital Library Proceedings.

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Mar 2019 • Advances in Photonics of Quantum Computing, Memory, and Communication XII …, 2019

Experimental validation of new bounds on nonlocal correlations (Conference Presentation)

Eliahu Cohen

First it will be shown that the nonlocal correlations of any hypothetical theory obeying two basic assumptions, namely, generalized uncertainty and relativistic causality, are bounded by the known quantum mechanical bounds. Then, novel bounds on quantum nonlocal correlations will be presented, including multipartitie and continuous variables scenarios. Experimental tests of some new bounds and concepts (performed with the Genovese and Karimi groups using SPDC photons) will be discussed. Finally, a few fundamental and practical implications on quantum entangled systems will be presented. This talk is based on past and on-going works with Avishy Carmi and the aforementioned experimental groups.

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Mar 2019 • 2019 12th German Microwave Conference (GeMiC), 170-173, 2019

Sinc-shaped, Nyquist Channel Demultiplexing with Silicon Photonics

Arijit Misra, Dvir Munk, Moshe Katzman, Stefan Preubler, Avi Zadok, Thomas Schneider

Sinc-shaped Nyquist pulses have a rectangular spectrum. In the spectral domain, adjacent Nyquist wavelength division multiplexed (WDM) channels can be multiplexed without any guard band. Theoretically, they can be used to transmit the maximum possible symbol and data rate. The demultiplexing of channels requires filters with transfer functions that are as close as possible to rectangular shapes. Here we present the successful demultiplexing of rectangular-shaped optical Nyquist dense wavelength division multiplexed channels, modulated with an advanced modulation format, with an eight-channel integrated silicon photonics device.

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