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Apr 2019 • Nano letters

Nanostructures, faceting, and splitting in nanoliter to yoctoliter liquid droplets

Shani Guttman, Ellina Kesselman, Avi Jacob, Orlando Marin, Dganit Danino, Moshe Deutsch, Eli Sloutskin

Contrary to everyday experience, where all liquid droplets assume rounded, near-spherical shapes, the temperature-tuning of liquid droplets to faceted polyhedral shapes and to spontaneous splitting has been recently demonstrated in oil-in-water emulsions. However, the elucidation of the mechanism driving these surprising effects, as well as their many potential applications, ranging from faceted nanoparticle synthesis through new industrial emulsification routes to controlled-release drug delivery within the human body, have been severely hampered by the micron-scale resolution of the light microscopy employed to date in all in situ studies. Thus, the thickness of the interfacially frozen crystalline monolayer, suggested to drive these effects, could not be directly measured, and the low limit on the droplet size still showing these effects remained unknown. In this study, we employ a combination of super-resolution …

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Apr 2019 • Solid state nuclear magnetic resonance

Dynamics in hydrophilic and hydrophobic molecular chains tethered to MCM41-type mesoporous silica upon wetting and dehydration processes

Lee Ghindes-Azaria, Ofer Melamed, Merav Nadav-Tsubery, Esthy Levy, Keren Keinan-Adamsky, Gil Goobes

Surface modified mesoporous silica materials are important materials for heterogeneous catalysis and are attracting attention as potential drug carriers. The functionality of these materials relies on the physical and chemical properties of the tethers attached to MCM41 silica surface. These chemically linked tails act as molecular brushes, that can capture pollutant molecules, anchor points for catalysts and can host drug molecules. To utilize the full potential of the tailored silica surfaces, one should infer their properties at different levels of solvation. Here, 1H MAS NMR spectroscopy is used to monitor the dynamic properties of two modified MCM41 materials, an aminopropyl tethered MCM41 and an octyl tethered MCM41, through the process of controlled hydration. The surface site resolved measurements demonstrate how the chemical nature of the two tethers governs the way water molecules are directed to the …

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Apr 2019 • Nature Reviews Materials 4 (4), 269-285, 2019

Photovoltaic solar cell technologies: analysing the state of the art

Pabitra K Nayak, Suhas Mahesh, Henry J Snaith, David Cahen

The remarkable development in photovoltaic (PV) technologies over the past 5 years calls for a renewed assessment of their performance and potential for future progress. Here, we analyse the progress in cells and modules based on single-crystalline GaAs, Si, GaInP and InP, multicrystalline Si as well as thin films of polycrystalline CdTe and CuIn x Ga 1− x Se 2. In addition, we analyse the PV developments of the more recently emerged lead halide perovskites together with notable improvements in sustainable chalcogenides, organic PVs and quantum dots technologies. In addition to power conversion efficiencies, we consider many of the factors that affect power output for each cell type and note improvements in control over the optoelectronic quality of PV-relevant materials and interfaces and the discovery of new material properties. By comparing PV cell parameters across technologies, we appraise how far …

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Apr 2019 • Beilstein journal of nanotechnology

Tungsten disulfide-based nanocomposites for photothermal therapy

Tzuriel Levin, Hagit Sade, Rina Ben-Shabbat Binyamini, Maayan Pour, Iftach Nachman, Jean-Paul Lellouche

Nanostructures of transition-metal dichalcogenides (TMDC) have raised scientific interest in the last few decades. Tungsten disulfide (WS 2) nanotubes and nanoparticles are among the most extensively studied members in this group, and are used for, eg, polymer reinforcement, lubrication and electronic devices. Their biocompatibility and low toxicity make them suitable for medical and biological applications. One potential application is photothermal therapy (PTT), a method for the targeted treatment of cancer, in which a light-responsive material is irradiated with a laser in the near-infrared range. In the current article we present WS 2 nanotubes functionalized with previously reported ceric ammonium nitrate–maghemite (CAN-mag) nanoparticles, used for PTT. Functionalization of the nanotubes with CAN-mag nanoparticles resulted in a magnetic nanocomposite. When tested in vitro with two types of cancer cells, the functionalized nanotubes showed a better PTT activity compared to non-functionalized nanotubes, as well as reduced aggregation and the ability to add a second-step functionality. This ability is demonstrated here with two polymers grafted onto the nanocomposite surface, and other functionalities could be additional cancer therapy agents for achieving increased therapeutic activity.

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Apr 2019 • Frontiers in pharmacology

Zinc-doped copper oxide nanocomposites inhibit the growth of pancreatic cancer by inducing autophagy through AMPK/mTOR pathway

Xiao Li, Huanli Xu, Cong Li, Gan Qiao, Ammad Ahmad Farooqi, Aharon Gedanken, Xiaohui Liu, Xiukun Lin

Zinc doped copper oxide nanocomposites (Zn-CuO NPs) is a novel doped metal nanomaterial synthesized by our group using the sonochemical method. Our previous studies have shown that Zn-CuO NPs could inhibit cancer cell proliferation by inducing apoptosis via ROS-mediated pathway. In the present study, we studied the anticancer effect of Zn-CuO NPs on human pancreatic cancer cells. MTS assay revealed that Zn-CuO NPs was able to inhibit cancer cell growth. TEM, flow cytometry and fluorescence microscope analysis showed that Zn-CuO NPs induced autophagy significantly; the number of autophagosomes increased obviously in cells treated with Zn-CuO NPs. Western blot analysis revealed that treatment with the NPs resulted in activation of AMPK/mTOR pathway in both AsPC-1 and MIA Paca-2 cells in dose dependent manners. Moreover, in the presence of AMPK activator AMPKinone, the protein level of p-AMPK, p-ULK1, Beclin-1 and LC3-II/LC3-I increased, while the protein expression of p-AMPK, p-ULK1, Beclin-1 and LC3-II/LC3-I decreased in the presence of AMPK inhibitor Compound C. In vivo study using xenograft mice revealed that Zn-CuO NPs significantly inhibited tumor growth with low toxicity. Our study confirms that Zn-CuO NPs inhibit the tumor growth both in vitro and in vivo for pancreatic cancer. AMPK/mTOR pathway plays an important role in the NPs induced inhibition of tumor growth.

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Apr 2019 • Phase Transitions

Magnetic phase transitions around room temperature in Cu9S5

Annette Setzer, Pablo D Esquinazi, Lukas Botsch, Oliver Baehre, Eti Teblum, Anat Itzhak, Olga Girshevitz, Gilbert Daniel Nessim

We have studied the magnetization of a recently synthesized CuS compound and found two phase transitions around room temperature. The phase transitions in the crystalline structure, characterized by XRD studies, are accompanied by changes also in the electrical resistivity. A hysteretic first-order phase transition has been found between 260 and 320 K, from a low-temperature paramagnetic anilite phase to a diamagnetic high-temperature low-digenite phase. A second order phase transition was recognized at ≃ 352 K from low digenite to a paramagnetic high-digenite structure at high temperatures.

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

Metal-based nanoparticles as carriers of mTHPC drug for effective photodynamic therapy

Elina Haimov, Yifat Harel, Shlomi Polani, Hana Weitman, David Zitoun, Jean-Paul Lellouche, Orit Shefi

Photodynamic therapy (PDT) is a promising therapeutic modality for cancer treatment. It considered to be minimallyinvasive and nontoxic. Clinical PDT involves systemic administration of photosensitizer drugs, which accumulate at the tumor area and are light sensitive. When laser illuminates the tumor area in the presence of molecular oxygen, highly reactive singlet oxygen is generated, causing to direct killing of the tumor. Despite the advantages of the classical PDT, it suffers from several limitations, impeding its clinical outcome. Thus, developing targeted delivery systems for photosensitizer drugs that will enhance the selectivity is urgently needed. We develop functionalized metal nanoparticles (NPs) as carriers of mTHPC photosensitizer drug. Herein we use NPs composed of either gold or magnetically responsive carries like Ce-doped and Yb-doped -γ-Fe2O3 maghemite NPs (MNPs). All nanocomposites form …

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Mar 2019 • Optica

Ultra-low-loss integrated visible photonics using thin-film lithium niobate

Boris Desiatov, Amirhassan Shams-Ansari, Mian Zhang, Cheng Wang, Marko Lončar

Integrated photonics is a powerful platform that can improve the performance and stability of optical systems while providing low-cost, small-footprint, and scalable alternatives to implementations based on free-space optics. While great progress has been made on the development of low-loss integrated photonics platforms at telecom wavelengths, the visible wavelength range has received less attention. Yet, many applications utilize visible or near-visible light, including those in optical imaging, optogenetics, and quantum science and technology. Here we demonstrate an ultra-low-loss integrated visible photonics platform based on thin-film lithium niobate on an insulator. Our waveguides feature ultra-low propagation loss of 6 dB/m, while our microring resonators have an intrinsic quality factor of 11 million, both measured at 637 nm wavelength. Additionally, we demonstrate an on-chip visible intensity modulator …

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Mar 2019 • Silicon Photonics XIV 10923, 1092309, 2019

Direct thermo-optical tuning of silicon photonic devices (Conference Presentation)

Paul Chevalier, Lara Koehler, Euijae Shim, Boris Desiatov, Amirhassan Shams-Ansari, Marco Piccardo, Marko Loncar, Michal Lipson, Alexander Gaeta, Federico Capasso

Thanks to its high Kerr non-linearity and its low linear absorption, silicon is a material of choice for optical devices in the mid-infrared (from 3 to 5 microns) such as microresonators. In this wavelength range, the available optical sources such as quantum cascade lasers have a limited tunability. Tuning the refractive index of silicon can be achieved by a temperature change of the chip and has been previously demonstrated on ring resonators using integrated heaters or thermo-electric elements. We present a new method for thermo-optical tuning of silicon devices by directly using the light from a laser diode operating at 450 nm. The blue light focused on the silicon induces a local elevation of temperature and thus the refractive index locally increases. When applying this method on silicon ring resonator, the elevation of temperature leads to a decreasing free-spectral range and thus shift the resonances to lower …

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Mar 2019 • Journal of colloid and interface science

Self-faceting of emulsion droplets as a route to solid icosahedra and other polyhedra

Orlando Marin, Maria Alesker, Shani Guttman, Gregory Gershinsky, Eitan Edri, Hagay Shpaisman, Rodrigo E Guerra, David Zitoun, Moshe Deutsch, Eli Sloutskin

Hypothesis Temperature-controlled self-faceting of liquid droplets has been recently discovered in surfactant-stabilized alkane-in-water emulsions. We hypothesize that similar self-faceting may occur in emulsion droplets of UV-polymerizable linear hydrocarbons. We further hypothesize that the faceted droplet shapes can be fixed by UV-initiated polymerization, thus providing a new route towards the production of solid polyhedra. Experiments Temperature-induced shape variations were studied by optical microscopy in micron-size emulsion droplets of UV-polymerizable alkyl acrylate. When polymerized, the resultant solid particles’ 3D shape and internal structure were determined by combined scanning electron microscopy (SEM) and focused ion beam (FIB) slicing. The SEM and FIB nanoscale resolution provided a far greater detail imaging than that achievable for the liquid droplets, which could only be studied …

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Mar 2019 • Journal of Membrane Science

Modification of a polypropylene feed spacer with metal oxide-thin film by chemical bath deposition for biofouling control in membrane filtration

Chidambaram Thamaraiselvan, Yacov Carmiel, Gary Eliad, Chaim N Sukenik, Raphael Semiat, Carlos G Dosoretz

Surface modification of polypropylene feed spacers typical of spiral wound membrane modules was studied by generation of crystalline ZnO nanorods. A seeding layer made by deposition of ZnO nanoparticles (20–40–60 nm diameter) from aqueous dispersions served as nucleation centers for crystallization. A uniform layer of ZnO nanorods was grown on the seeding layer by chemical bath deposition from a zinc acetate solution. Biocidal activity was estimated by antibacterial tests in static liquid culture against Escherichia coli and antibiofouling tests in flow-through/cross-flow mode against a mixture of Pseudomonas fluorescens and Bacillus subtilis. Best biocidal activity was displayed by 20 nm ZnO particles, suggesting a tradeoff between surface coverage, roughness and particle size. Although the seed layer itself displayed acceptable antibacterial activity, a marked improvement was achieved by the …

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Mar 2019 • Bioinformatics

A cluster robustness score for identifying cell subpopulations in single cell gene expression datasets from heterogeneous tissues and tumors

Itamar Kanter, Piero Dalerba, Tomer Kalisky

Motivation A major aim of single cell biology is to identify important cell types such as stem cells in heterogeneous tissues and tumors. This is typically done by isolating hundreds of individual cells and measuring expression levels of multiple genes simultaneously from each cell. Then, clustering algorithms are used to group together similar single-cell expression profiles into clusters, each representing a distinct cell type. However, many of these clusters result from overfitting, meaning that rather than representing biologically meaningful cell types, they describe the intrinsic ‘noise’ in gene expression levels due to limitations in experimental precision or the intrinsic randomness of biochemical cellular processes. Consequentially, these non-meaningful clusters are most sensitive to noise: a slight shift in gene expression levels due to a repeated measurement will rearrange the grouping of data points …

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

Calibration iso-pathlength point in cylindrical tissue geometry: comparing steady state photon diffusion to Monte Carlo simulation

Hamootal Duadi, Daqing Piao, Dror Fixler

Light-tissue interactions are commonly studied for near infra-red (NIR) spectroscopy for imaging and diagnosis. While imaging is bound to the surface due to the high tissue scattering, many diagnosis methods, such as the photoplethysmograph (PPG) and pulse oximeter, focus on sensing instead of imaging. There are two approaches for the investigation of light-tissue interactions: one numerical and the other analytical. The most common numerical method is the Monte Carlo (MC) simulation, which is a statistical study of photon migration from the optical properties of the different tissue regions. However, the yield of such statistical approaches is limited. Analytical methods are commonly based on the diffusion theory, yet they are inaccurate near the light source. There are several solution methods, where extrapolated boundary conditions lead to a more accurate solution. Previously, we proposed measuring the …

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

Enhanced entangled-photon-pair interaction with metallic nanoparticles

Ariel Ashkenazy, André Stefanov, Dror Fixler

In recent years, many quantum lights-based applications were suggested, ranging from encrypted communication and precision metrology to fluorescent biomolecules detection and advanced spectroscopy schemes. Such applications mostly rely on entanglement, the property of correlations between particles which cannot be explained by classical mechanisms, to overcome classical light limitations. Some of these applications, e.g. nonlinear spectroscopy, require the use of entangled-photon-pair interaction (EPPI) with the matter. However, such entangled pairs, generated through spontaneous parametric down-conversion (SPDC), are scarce, and multi-photon interaction with matter is usually very weak and barely detectable. Therefore, an enhancement of this interaction is needed. In our research, we investigate a novel way to achieve such enhanced EPPI using metallic nanoparticles (MNPs), which are known …

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Mar 2019 • Nature Physics

Strain-tunable magnetism at oxide domain walls

DV Christensen, Y Frenkel, YZ Chen, YW Xie, ZY Chen, Y Hikita, A Smith, L Klein, HY Hwang, N Pryds, B Kalisky

Applying stress to a ferroelastic material results in a nonlinear strain response as domains of different orientations mechanically switch. The ability to write, erase and move domain walls between such ferroelastic domains suggests a method for making nanoelectronics where the domain wall is the device. However, little is known about the magnetic properties of such domain walls. A fascinating model system is SrTiO 3, where the ferroelastic domain walls display strain-tunable polarity and enhanced conductivity. Here, we reveal a long-range magnetic order with modulations along the ferroelastic domain walls in SrTiO 3 and SrTiO 3-based heterointerfaces, which manifests itself as a striped pattern in scanning superconducting quantum interference device maps of the magnetic landscape. In conducting interfaces, the magnetism is coupled to itinerant electrons with clear signatures in magnetotransport …

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Mar 2019 • arXiv preprint arXiv:1903.09317

Scientific opportunities with an X-ray free-electron laser oscillator

Bernhard Adams, Gabriel Aeppli, Thomas Allison, Alfred QR Baron, Phillip Bucksbaum, Aleksandr I Chumakov, Christopher Corder, Stephen P Cramer, Serena DeBeer, Yuntao Ding, Jörg Evers, Josef Frisch, Matthias Fuchs, Gerhard Grübel, Jerome B Hastings, Christoph M Heyl, Leo Holberg, Zhirong Huang, Tetsuya Ishikawa, Andreas Kaldun, Kwang-Je Kim, Tomasz Kolodziej, Jacek Krzywinski, Zheng Li, Wen-Te Liao, Ryan Lindberg, Anders Madsen, Timothy Maxwell, Giulio Monaco, Keith Nelson, Adriana Palffy, Gil Porat, Weilun Qin, Tor Raubenheimer, David A Reis, Ralf Röhlsberger, Robin Santra, Robert Schoenlein, Volker Schünemann, Oleg Shpyrko, Yuri Shvyd'Ko, Sharon Shwartz, Andrej Singer, Sunil K Sinha, Mark Sutton, Kenji Tamasaku, Hans-Christian Wille, Makina Yabashi, Jun Ye, Diling Zhu

An X-ray free-electron laser oscillator (XFELO) is a new type of hard X-ray source that would produce fully coherent pulses with meV bandwidth and stable intensity. The XFELO complements existing sources based on self-amplified spontaneous emission (SASE) from high-gain X-ray free-electron lasers (XFEL) that produce ultra-short pulses with broad-band chaotic spectra. This report is based on discussions of scientific opportunities enabled by an XFELO during a workshop held at SLAC on June 29 - July 1, 2016

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Mar 2019 • Colloidal nanoparticles for biomedical applications XIV 10892, 1089214, 2019

Element (B, N, P) doped carbon dots interaction with neural cells: promising results and future prospective

Raj Kumar, Vijay Bhooshan Kumar, Michal Marcus, Aharon Gedanken, Orit Shefi

Here, we report the preparation of carbon dots (CDs) and doping with different elements namely boron, nitrogen and phosphorous using facile single step hydrothermal method. We used biopolymers as the source material for CDs synthesis. The prepared carbon dots and elements (B, N and P) doped carbon dots’ physicochemical properties are investigated using different analytical techniques. Several analytical characteristics such as Uv-visible spectroscopy, fluorescent spectroscopy and transmission electron microscopy confirm the doping of element into carbon dots. From DLS analysis it was found that the prepared carbon dots are range from 3-9 nm. Excitation dependent fluorescence with high quantum yields for B and N doped CDs showed 47% and 44%, respectively. The doped CDs impact on cell viability was investigated against neuronal PC12 cells. Interestingly, the prepared carbon dots did not affect …

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Mar 2019 • FlatChem

Electrochemical intercalation of sodium in vertically aligned molybdenum disulfide for hydrogen evolution reaction

Victor Shokhen, David Zitoun

The intercalation of alkaline cations such as lithium and sodium into two-dimensional (2D) van der Waals materials effectively modifies their electronic structure. Here, we show an electrochemical intercalation process of an alkaline ion (Li+ or Na+), into vertically aligned molybdenum disulfide (MoS2) thin films by using a three-electrode flooded vessel cell, and its application as electrocatalyst for hydrogen evolution reaction. The electrochemical intercalation method is controlled by the applied current density. After electrochemical insertion, the vertically alligned MoS2 layers display an extended Wan der Waals gap. The Li and Na intercalated vertically alligned MoS2 layers demonstrate an overpotential of 0.29 V at 10 mA cm−2 towards hydrogen evolution reaction (HER) in 0.5 M H2SO4. The intercalation of Li+ or Na+ leads to the partial exfoliation of the 2D layered material. Nevertheless, the Na intercalated …

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Mar 2019 • Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical …, 2019

Predicting treatment outcome and enhancing immunotherapy with anti-PDL1 gold nanoparticles

Rinat Meir, Katerina Shamalov, Cyrille J Cohen, Rachela Popovtzer

Immune checkpoint blockade (ICB) has shown unprecedented clinical success in treatment of cancer. However, not all patients show adequate response, and the treatment can lead to a broad range of adverse effects. Therefore, early identification of potential responders to therapy, using non-invasive means, is a critical challenge for improving ICB. Herein, we engineered anti-Programmed Death Ligand 1 (aPDL1) nanoparticles with enhanced ICB immunotherapy efficacy. Using a mouse model for colon cancer, we show that the nanoparticles accumulated, penetrated and efficiently prevented tumor growth. Moreover, we found a direct correlation between the amount of nanoparticle accumulation within the tumor at 48 hours, as determined by CT, and the therapeutic response. This enabled subject stratification as potential responders or non-responders, at an early time point. Thus, by integrating prognostic and …

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Mar 2019 • Virology

The KSHV portal protein ORF43 is essential for the production of infectious viral particles

Daniela Dana Dünn-Kittenplon, Inna Kalt, Jean-Paul Moshe Lellouche, Ronit Sarid

Herpesvirus capsid assembly involves cleavage and packaging of the viral genome. The Kaposi's sarcoma-associated herpesvirus (KSHV) open reading frame 43 (orf43) encodes a putative portal protein. The portal complex functions as a gate through which DNA is packaged into the preformed procapsids, and is injected into the cell nucleus upon infection. The amino acid sequence of the portal proteins is conserved among herpesviruses. Here, we generated an antiserum to ORF43 and determined late expression kinetics of ORF43 along with its nuclear localization. We generated a recombinant KSHV mutant, which fails to express ORF43 (BAC16-ORF43-null). Assembled capsids were observed upon lytic induction of this virus; however, the released virions lacked viral DNA and thus could not establish infection. Ectopic expression of ORF43 rescued the ability to produce infectious particles. ORF43 antiserum …

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Mar 2019 • arXiv preprint arXiv:1903.05959

Effect of liquid state organization on microstructure and strength of model multicomponent solids

Kulveer Singh, Yitzhak Rabin

When a multicomponent liquid composed of particles with random interactions is slowly cooled below the freezing temperature, the fluid reorganises in order to increase (decrease) the number of strong (weak) attractive interactions and solidifies into a microphase-separated structure composed of domains of strongly and of weakly interacting particles. Using Langevin dynamics simulations of a model system we find that the limiting tensile strength of such solids can exceed that of one-component solids.

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