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Jul 2019 • Polymers

Controlled Shape and Porosity of Polymeric Colloids by Photo-Induced Phase Separation

Elad Hadad, Eitan Edri, Hagay Shpaisman

The shape and porosity of polymeric colloids are two properties that highly influence their ability to accomplish specific tasks. For micro-sized colloids, the control of both properties was demonstrated by the photo-induced phase separation of droplets of NOA81—a thiol-ene based UV-curable adhesive—mixed with acetone, water, and polyethylene glycol. The continuous phase was perfluoromethyldecalin, which does not promote phase separation prior to UV activation. A profound influence of the polymer concentration on the particle shape was observed. As the photo-induced phase separation is triggered by UV radiation, polymerization drives the extracted solution out of the polymeric matrix. The droplets of the extracted solution coalesce until they form a dimple correlated to the polymer concentration, significantly changing the shape of the formed solid colloids. Moreover, control could be gained over the porosity by varying the UV intensity, which governs the kinetics of the reaction, without changing the chemical composition; the number of nanopores was found to increase significantly at higher intensities. View Full-Text

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Jul 2019 • IEEE

Label Free Super-Resolved Nanoscopy: PALM-Like, STED-Like and Hybrid AFM/NSOM

Avi Karsenty, Avraham Chelly, M Sinvani, H Pinhas, Omer Wagner, Yossef Danan, Zeev Zalevsky

In this presentation we will show three advanced techniques for label-free super-resolved nanoscopy. We will start by presenting a PALM-like concept in which localization precision is converted into spatial imaging resolution. The concept is based upon usage of metallic freely moving nano-particles interacting with the inspected sample. Their temporal-spatial properties of light scattering are used to construct the super-resolved image. This concept is a linear nanoscopy that does not use the non-linearity of fluorescence dye. Then, we will present a STED-like approach in which the non-linearity of plasma dispersion effect of silicon is used in order to generate a sub-wavelength point spread function and to scan with it the inspected silicon wafer. This approach is good for failure analysis of micro-electronic integrated chips or for biomedical imaging if instead of silicon wafers we use silicon freely moving nano-particles …

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Jul 2019 • arXiv preprint arXiv:1907.11218

Requirements for functional pn-homojunctions in lead-halide perovskite solar cells

Thomas Kirchartz, David Cahen

Cui et al. describe the fabrication and characterization of planar pn-junction solar cells based on lead-halide perovskites. The doping densities measured using Hall effect measurements vary from to for the solution-processed n-type layer and for the evaporated p-type layer. While these devices outperform their counterparts, that are supposedly un-doped, the results raise three important questions: (i) Are the reported doping densities high enough to change the electrostatic potential distribution in the device from that for the un-doped ones, (ii) are the doping densities high enough for the pn-junction to remain intact under typical photovoltaic operation conditions and (iii) is a pn-junction beneficial for photovoltaic performance given the typical properties of lead-halide perovskites.

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Jul 2019 • International Society for Optics and Photonics

Secondary speckle-based tomography and tissue probing (Conference Presentation)

Ariel Schwarz, Nisan Ozana, Ran Califa, Amir Shemer, Hadar Genish, Zeev Zalevsky

We will present how one can use the spatial-temporal analysis of secondary speckle patterns that are generated when laser light is back scattered from a tissue in order to measure the nano-vibrations (tilting associated vibrations) occurring in the tissue and in order to map its elastography. In addition to the fundamental nano-vibrations sensing capability, the proposed configuration allows by applying time multiplexing approach also to perform separation of photons coming from different depths of the tissue while externally stimulating the tissue via infra-sonic vibration. This yields a tomographic capability. The proposed configuration uses a modulated laser that allows combining a speckle pattern tracking method for surface tilting changes sensing with a Mach–Zehnder interferometer-based speckle patterns configuration to achieve z-axis detection (movement of the whole surface in the z direction). We will also …

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Jul 2019 • Electrochemical Conference on Energy and the Environment (ECEE 2019 …, 2019

Bio-inspired Electrocatalysis-Session 2

Lior Elbaz

Jul 2019 • Investigative Ophthalmology & Visual Science

Reading performance in simulated prosthetic vision

Yossi Mandel

Presentation Description: Current retinal prostheses offer a promising solution to people with degenerative diseases of the outer retina. Notwithstanding, the obtained visual acuity is still severely limited and offers very basic vision restoration. In this lecture I will describe the main limitations of current retinal prosthetic approaches and will describe the concept of" active sensing", where super-resolved vision is achieved by actively scanning the visual scene. To simulate prosthetic vision reading, we displayed pixelated word images at different phosphene densities and contrasts. We measured word recognition rate and reading speed for various phosphene densities and contrasts with and without active sensing or zoom. Our results show that active scanning can significantly increase reading performance in simulated prosthetic vision and yield super-resolving capabilities. These results highlight the importance of a …

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Jul 2019 • Investigative Ophthalmology & Visual Science

Studying the biocompatibility and 3D cell-scaffold interaction of photoreceptor precursors in a microwells array

Amos Markus, Yoav Chemla, Gal Shpun, Itai Henn, Nairouz Farah, Yossi Mandel

Purpose: Delivering cells to replace degenerate cells in degenerative disease of the outer retina in the effort to restore vision carries great hope. Many approaches for optimizing the 3D scaffold for improving the spatial orientation, function, viability and potentially the synaptic formation of transplanted cells have been pursued, and are the focus of many studies. Here we investigated, in vitro, the morphological characterization and viability of single human photoreceptors precursors cells (hPRP) cells in microwells array.Methods:–hPRP were differentiated form human embryonic stem cells following a protocol optimized by our group. GFP labeled PRP cells were seeded on an SU8 scaffold array fabricated by lithography containing 17,424 wells 20µm in diameter and 17 µm in height suitable for a single cell dimension. SU8 surfaces were treated with serum, plasma, matrigel, collagen and PEI to enhance cell …

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Jul 2019 • Cancer Research 79 (13 Supplement), 1030-1030, 2019

Regulation and role of actin dynamics in promoting premalignant cell migration

Manash K Paul, Arkaprabha Basu, Bharti Bisht, Paul Pagano, Yari Fontebasso, Kostyantyn Krysan, Linh Tran, Mitchel Alioscha-Perez, John Minna, Dino DiCarlo, Hichem Sahli, Shimon Weiss, Steven M Dubinett

Lung cancer is a highly metastatic disease. Although commonly considered to be a late event in disease pathogenesis, micrometastasis may also occur as an early phenomenon. Induction of epithelial-mesenchymal transition (EMT) is associated with changes in mechanical properties, predominantly due to increased cell contractility and actin stress fiber formation. The molecular mechanisms regulating actin dynamics during EMT in premalignant cells have not yet been defined. Using a novel constricted migration selection strategy and physomic techniques, including deformability cytometry and atomic force microscopy, we identified a highly motile (HM) subpopulation of HBECs, with enhanced heritable migratory capacity both in vitro and in vivo. The HBECs used for selection were modified with genetic changes that can be found in premalignancy (p53null, activated Kras-G12D). Thus, this sub-population of HM …

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Jul 2019 • Optics and Lasers in Engineering

3D printed hand-held refractometer based on laser speckle correlation

Vismay Trivedi, Swapnil Mahajan, Mugdha Joglekar, Vani Chhaniwal, Zeev Zalevsky, Bahram Javidi, Arun Anand

Measurement of very small refractive index changes is very important from a material's characterization point of view. This paper demosntrates a compact, simple and accurate technique for measuring refractive indices of transparent liquids, based on Snell's law and laser speckle correlation. Furthermore, considering the cutting-edge technology of 3D printing and its ability to enhance a technique's functionality by providing a sturdy framework, a 3D printed hand-held device for measurement of refractive indices is also demonstrated. The device measures very small change in refractive index by measuring the change in the objective speckle pattern arising due to the change in laser light passing the liquid solution, which is caused by the apparent shift of a point source. Change in the speckle pattern is presented in terms of correlation coefficient which is computed by comparing a speckle pattern corresponding to …

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Jul 2019 • 2019 21st International Conference on Transparent Optical Networks (ICTON), 1-1, 2019

Plasmonics in Atomically Thin Crystalline Silver

Vahagn Mkhitaryan, Zakaria M Abd El-Fattah, J Brede, L Fernández, Qiushi Guo, Cheng Li, Arnab Ghosh, Doron Naveh, Fengnian Xia, JE Ortega, F García de Abajo

Summary from only given. We report on the fabrication of few-atomic-layer-thick wafer-scale crystalline silver films, along with the observation of plasmons in the near-to-mid infrared spectral regions upon lithographic structuring. Our measured optical spectra reveal narrow plasmons (quality factor ~ 4), further supported by a low sheet resistance comparable to bulk metal in few-atomic-layer silver films down to 7 Ag(111) monolayers. Good crystal quality and plasmon narrowness are obtained despite the addition of a thin passivating dielectric, which renders our samples resilient to ambient conditions.

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Jul 2019 • Electrochemical Conference on Energy and the Environment (ECEE 2019 …, 2019

Lithium-ion Batteries: From the Design of New Electrode Materials and Electrolytes to the Performance and Recycling of Industrial Systems-Session 5

Shirley Meng, Doron Aurbach

Jul 2019 • The Journal of Physical Chemistry C

Direct formation of carbocyanine J-aggregates in organic solvent

Sivan Harazi, Omree Kapon, Amos Sharoni, Ya’akov R Tischler

J-aggregates are molecular nanoscale self-assemblies with distinct excitonic properties, such as highly delocalized excitons, making them main candidates for designing excitonic energy transfer systems. Here, we show a technique to form J-aggregates of the cyanine dye 1,1′-dioctyl-3,3′-di(4sulfobutyl)-5,5′,6,6′-tetrachloro-benzimidazolocarbocyanine (C8S4) in organic solutions of chloroform and acetone. These J-aggregates have a spectrum with three red-shifted absorption peaks and two sharp emission peaks. Spin-coated thin films of C8S4 aggregates have similar spectra. Investigation of the thin films via electron microscopy shows two morphologies of aggregates, which partially explains the complicated spectra. We have shown two ways for isolating the type of aggregate with the lowest transition energy. Atomic force microscopy and high-resolution transmission electron microscopy images of the …

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Jul 2019 • Investigative Ophthalmology & Visual Science

Cortical response to combined prosthetic and visible stimuli exhibits similarities to natural visual processing

Yossi Mandel, Tamar Arens-Arad, Nairouz Farah, Avital Moshkovitz, Rivkah Lender, Thomas Flores, Daniel V Palanker

Purpose: Prosthetic restoration of central vision in age-related macular degeneration (AMD) involves a combination of prosthetic vision in the central macula along with natural vision in the periphery. Here we study cortical interaction of visible and prosthetic stimuli, which is of great clinical and scientific importance.Methods: Subretinal implantation of 1mm-diameter photovoltaic arrays in wild-type rats induced a localized degeneration of the photoreceptors above the implant, whereas the surrounding retina was left intact, similar to the localized retinal degeneration caused by AMD. Using a customized projection system, we induced prosthetic and natural visual responses with NIR (910nm) and visible light (532nm), respectively. Each presentation was comprised of a central 1mm prosthetic or visible stimulus encircled with a 3mm visible surround. We recorded visual evoked potentials (VEP) in response to either non …

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Jul 2019 • New Journal of Physics

Bounds on nonlocal correlations in the presence of signaling and their application to topological zero modes

Avishy Carmi, Yaroslav Herasymenko, Eliahu Cohen, Kyrylo Snizhko

Bell's theorem renders quantum correlations distinct from those of any local-realistic model. Although being stronger than classical correlations, quantum correlations are limited by the Tsirelson bound. This bound, however, applies for Hermitian, commutative operators corresponding to non-signaling observables in Alice's and Bob's spacelike-separated labs. As an attempt to explore theories beyond quantum mechanics and analyze the uniqueness of the latter, we examine in this work the extent of non-local correlations when relaxing these fundamental assumptions, which allows for theories with non-local signaling. We prove that, somewhat surprisingly, the Tsirelson bound in the Bell–Clauser–Horne–Shimony–Holt scenario, and similarly other related bounds on non-local correlations, remain effective as long as we maintain the Hilbert space structure of the theory. Furthermore, in the case of Hermitian …

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Jul 2019 • Investigative Ophthalmology & Visual Science

Electrophysiological characterization of human embryonic stem cells-derived photoreceptor precursors

Nairouz Farah, Revital Schick, Amos Markus, Yossi Mandel

Purpose: Photoreceptor precursor cells (PRPs) differentiated from embryonic stem cells (ESC) can serve as a source for cell replacement therapy aimed at vision restoration in patients suffering from degenerative diseases of the outer retina, such as retinitis pigmentosa and age related macular degeneration. This work presents the thorough electrophysiological activity characterization of PRPs, and the investigation of their expression pattern of different voltage-gated ion channels.Methods: Human embryonic stem cells were differentiated into PRPs and whole-cell recordings at four time points along the differentiation process were performed for electrophysiological characterization. In addition, qPCR analysis was performed at these 4 time-points to characterize the expression pattern of various ion channels which shape the electrophysiological response. Finally, to characterize the electrically induced calcium …

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Jul 2019 • ChemElectroChem

Fluorination of Li‐Rich Lithium‐Ion‐Battery Cathode Materials by Fluorine Gas: Chemistry, Characterization, and Electrochemical Performance in Half Cells

Ulf Breddemann, Evan M Erickson, Victoria Davis, Florian Schipper, Mathias Ellwanger, Michael Daub, Anke Hoffmann, Christoph Erk, Boris Markovsky, Doron Aurbach, Ingo Krossing

Mild fluorination of high‐energy nickel‐cobalt‐manganese (HE‐NCM) materials with low pressures of elementary fluorine gas (F2) at room temperature was systematically studied. The fluorinated HE‐NCM samples were analysed by ion chromatography, inductively coupled plasma mass spectrometry, FT‐IR spectroscopy, powder X‐ray diffraction, magic angle spinning NMR spectroscopy, scanning electron microscopy, thermo‐gravimetric analysis, differential thermal analysis, electrochemical testing, and X‐ray photoelectron spectroscopy. The treatment of the cathode materials with low pressures (a few hundred mbar) of elementary fluorine gas at room temperature led to the elimination of the basic surface film (LiOH, Li2CO3, Li2O, etc.), and the resulting thin amorphous LiF film led to increased capacity and long‐term stability of the battery. Impedance built‐up was greatly reduced for these systems throughout …

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Jul 2019 • ACS omega

Does the ATSM-Cu (II) biomarker integrate into the human cellular copper cycle?

Gulshan R Walke, Sharon Ruthstein

Hypoxia is commonly encountered in the tumor microenvironment and drives proliferation, angiogenesis, and resistance to therapy. Imaging of hypoxia is important in many disease states in oncology, cardiology, and neurology. Finding clinically approved imaging biomarkers for hypoxia has proved challenging. Candidate biomarkers have shown low uptake into tumors and low signal to background ratios that adversely affect imaging quality. Copper complexes have been identified as potential biomarkers for hypoxia owing to their redox ability. Active uptake of copper complexes into cells could ensure selectivity and high sensitivity. We explored the reactivity and selectivity of the ATSM-Cu(II) biomarker to proteins that are involved in the copper cycle using electron paramagnetic resonance (EPR) spectroscopy and UV–vis measurements. We show that the affinity of the ATSM-Cu(II) complex to proteins in the …

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Jul 2019 • ACS Energy Letters 4 (8), 1907-1917, 2019

Diffusion-Induced Transient Stresses in Li-Battery Electrodes Imaged by Electrochemical Quartz Crystal Microbalance with Dissipation Monitoring and Environmental Scanning …

Netanel Shpigel, Mikhael D Levi, Xiaopeng Cheng, Tianci Cao, Rui Wu, Tyler S Mathis, Yuefei Zhang, Doron Aurbach, Yury Gogotsi

Quick charging of Li-ion batteries is often accompanied by rapid expansion of composite battery electrodes, resulting in the appearance of transient stresses inside the electrodes’ bulk. Although predicted theoretically, they have never been tracked by direct in situ measurements. Herein, using multiharmonic electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D), acoustic images of strong transient deformations in LiFePO4 electrodes were obtained in the form of giant resonance frequency and resonance width shifts. The formation of cracks was verified by scanning electron microscopy. The effects of charging rate, stiffness of the polymeric binder, and solution concentration have been identified. The attractive feature of EQCM-D is its high sensitivity for selective probing of average mechanical characteristics of the operated electrodes, especially of the particle–binder interactions, directly …

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Jul 2019 • European Polymer Journal

Poly (styryl bisphosphonate) nanoparticles with a narrow size distribution: synthesis, characterization and antibacterial applications

Hanna P Steinmetz, Safra Rudnick-Glick, Michal Natan, Ehud Banin, Shlomo Margel

Bacterial resistance to antibiotics is a major challenge in health research. A recent approach to combat this resistance is by interfering with vital bacterial functional systems. Calcium ions play an important role in bacterial functions such as bacterial cell stability, regulation of virulence genes, and in the function of various intracellular proteins. Bisphosphonate compounds have a high affinity for calcium ions and the antibacterial activity of bisphosphonates in combination with antibiotics has been recently studied. However, the antibacterial behavior of the bisphosphonate group itself has hardly been investigated. New cross-linked poly(styryl bisphosphonate) nanoparticles (poly(StBP) NPs) with a narrow size distribution and high yield were engineered using a dispersion copolymerization of styryl bisphosphonate monomer with the cross-linking monomer triethylene glycol diacrylate and the primary amino monomer N …

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Jul 2019 • ChemElectroChem

LNMO‐Graphite Cells Performance Enhancement by the Use of Acid Scavenging Separators

Yuliya Shilina, Satyanarayana Maddukuri, Anjan Banerjee, Baruch Ziv, Shalom Luski, Doron Aurbach, Ion C Halalay

The performance of cells with high‐voltage LiNi0.5Mn1.5O4 positive electrodes and graphite negative electrodes is affected most adversely by the decomposition of LiPF6‐based electrolyte solutions components and the dissolution of transition metal (TM) ions. Novel approaches to overcome the severe degradation of performance are crucial for the successful design and commercialization of LNMO‐based cells, which are very advantageous due to their high voltage (4.7 V). Acid‐scavenging separators based on poly(divinylbenzene‐4‐vinylpyridine) were tested as a mean for enhancing the stability of LNMO/graphite cells with an additives‐free standard 1 M LiPF6/EC : EMC (3 : 7 v/v) electrolyte solution. Improved cycling performance was demonstrated over reference cells containing commercial polypropylene separators during prolonged cycling at both 30 and 45 °C. Electrochemical impedance …

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Jul 2019 • European journal of medicinal chemistry

An oligonucleotide probe incorporating the chromophore of green fluorescent protein is useful for the detection of HER-2 mRNA breast cancer marker

Abed Saady, Verena Böttner, Melissa Meng, Eli Varon, Yaron Shav-Tal, Christian Ducho, Bilha Fischer

Diagnosis and treatment of breast cancer can be greatly enhanced and personalized based on the quantitative detection of mRNA markers. Here, we targeted the development of a fluorescent oligonucleotide probe to detect specifically the HER-2 mRNA breast cancer marker. We have selected the chromophore of the Green Fluorescent Protein (GFP), 4-hydroxybenzylidene imidazolinone (HBI), as a fluorophore covalently bound to an oligonucleotide probe and potentially capable of intercalating within a probe-mRNA duplex. We first synthesized the two-ring scaffold of the HBI chromophore 5 and coupled it to 2′-deoxyuridine at C5-position via a 7-atom-spacer, to give 4. Indeed, in the highly viscous glycerol used to mimic the reduced conformational flexibility of the intercalated HBI, chromophore 4 displayed a quantum yield of 0.29 and brightness of 20600 M−1cm−1, while no fluorescent signal was observed in …

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