Sep 2020 • Journal of functional biomaterials
Moorthy Maruthapandi, Arumugam Saravanan, John HT Luong, Aharon Gedanken
CuO, TiO 2, or SiO 2 was decorated on polyaniline (PANI) by a sonochemical method, and their antimicrobial properties were investigated for two common Gram-negative pathogens: Pseudomonas aeruginosa (PA) and Klebsiella pneumoniae (KP). Without PANI, CuO, TiO 2, or SiO 2 with a concentration of 220 µg/mL exhibited no antimicrobial activities. In contrast, PANI-CuO and PANI-TiO 2 (1 mg/mL, each) completely suppressed the PA growth after 6 h of exposure, compared to 12 h for the PANI-SiO 2 at the same concentration. The damage caused by PANI-SiO 2 to KP was less effective, compared to that of PANI-TiO 2 with the eradication time of 12 h versus 6 h, respectively. This bacterium was not affected by PANI-CuO. All the composites bind tightly to the negative groups of bacteria cell walls to compromise their regular activities, leading to the damage of the cell wall envelope and eventual cell lysis. View Full-Text
Show moreSep 2020 • EMBO molecular medicine
Mor Hanan, Alon Simchovitz, Nadav Yayon, Shani Vaknine, Roni Cohen‐Fultheim, Miriam Karmon, Nimrod Madrer, Talia Miriam Rohrlich, Moria Maman, Estelle R Bennett, David S Greenberg, Eran Meshorer, Erez Y Levanon, Hermona Soreq, Sebastian Kadener
Circular RNAs (circRNAs) are brain‐abundant RNAs of mostly unknown functions. To seek their roles in Parkinson's disease (PD), we generated an RNA sequencing resource of several brain region tissues from dozens of PD and control donors. In the healthy substantia nigra (SN), circRNAs accumulate in an age‐dependent manner, but in the PD SN this correlation is lost and the total number of circRNAs reduced. In contrast, the levels of circRNAs are increased in the other studied brain regions of PD patients. We also found circSLC8A1 to increase in the SN of PD individuals. CircSLC8A1 carries 7 binding sites for miR‐128 and is strongly bound to the microRNA effector protein Ago2. Indeed, RNA targets of miR‐128 are also increased in PD individuals, suggesting that circSLC8A1 regulates miR‐128 function and/or activity. CircSLC8A1 levels also increased in cultured cells exposed to the oxidative stress …
Show moreSep 2020 • Developmental Neurobiology
Itai Henn, Ayelet Atkins, Amos Markus, Gal Shpun, Hannah‐Noa Barad, Nairouz Farah, Yossi Mandel
Tissue and neural engineering for various regenerative therapies are rapidly growing fields. Of major interest is studying the complex interface between cells and various 3D structures by scanning electron microscopy with focused ion beam. Notwithstanding its unrivaled resolution, the optimal fixation, dehydration, and staining protocols of the samples while preserving the complex cell interface in its natural form, are highly challenging. The aim of this work was to compare and optimize staining and sample drying procedures in order to preserve the cells in their “life‐like state” for studying the cell interface with either 3D well‐like structures or gold‐coated mushroom‐shaped electrodes. The process involved chemical fixation using a combination of glutaraldehyde and formaldehyde, followed by gentle drying techniques in which we compared four methods: (critical point drying, hexamethyldisiloxane, repeats of …
Show moreSep 2020 • Advanced Composites and Hybrid Materials
Bhawana Jain, Ajaya K Singh, Ayesha Hashmi, Md Abu Bin Hasan Susan, Jean-Paul Lellouche
Water pollution kills nearly 2 million people and costs trillions of dollars every year, which continuously threatens the survival of both human and animal species in the world. The textile industry is considered as pollutant-releasing industries in water. In this research work, we firstly report the synthesis of cerium oxide (CeO2) nanoparticles in the range of quantum dots (QDs). Syntheses of cerium oxide nanomaterials were assisted by using three different surfactants, i.e., sodium dodecyl sulfate (SDS; anionic), cetyltrimethylammonium bromide (CTAB; cationic), and cetylpyridinium chloride (CPC; cationic); the surfactants control the growth and particle size of the prepared material. The nanomaterials were characterized by UV-visible spectroscopy, X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, high-resolution transmission electron microscopy (HRTEM), and …
Show moreSep 2020 • APL Photonics
Avi Klein, Inbar Sibony, Sara Meir, Hamootal Duadi, Michelle Y Sander, Moti Fridman
We demonstrate a temporal imaging system that can capture events with unknown time-of-arrival in the time domain without the need to synchronize the signal. The temporal imaging system is based on a time-lens that uses a high repetition-rate fiber laser for the pump wave together with a time-stretch scheme. After dispersion, the timing between adjacent pump pulses is smaller than the pulse width. Therefore, the signal interacts with one of the pump pulses with high probability, regardless of its arrival time. We discuss the intensity dependence and temporal aberrations of such an imaging system and demonstrate a direct temporal imaging of the buildup dynamics of solitons.
Show moreSep 2020 • Investigative Ophthalmology & Visual Science
Revital Schick, Nairouz Farah, Amos Markus, Alon Korngreen, Yossi Mandel
Purpose: Photoreceptor precursor cells (PRPs) differentiated from human embryonic stem cells 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 AMD. In this work, we studied the electrophysiologic maturation of PRPs throughout the differentiation process.Methods: Human embryonic stem cells were differentiated into PRPs and whole-cell recordings were performed for electrophysiologic characterization at days 0, 30, 60, and 90 along with quantitative PCR analysis to characterize the expression level of various ion channels, which shape the electrophysiologic response. Finally, to characterize the electrically induced calcium currents, we employed calcium imaging (rhod4) to visualize intracellular calcium dynamics in response to electrical activation.Results: Our results revealed an early and steady presence (approximately 100% of responsive cells) of the delayed potassium rectifier current. In contrast, the percentage of cells exhibiting voltage-gated sodium currents increased with maturation (from 0% to almost 90% of responsive cells at 90 days). Moreover, calcium imaging revealed the presence of voltage-gated calcium currents, which play a major role in vision formation. These results were further supported by quantitative PCR analysis, which revealed a significant and continuous (3-to 50-fold) increase in the expression of various voltage-gated channels concomitantly with the increase in the expression of the photoreceptor marker CRX.Conclusions: These results can shed light on the electrophysiologic …
Show moreSep 2020 • Nature Energy 5 (9), 646-656, 2020
Yanliang Liang, Hui Dong, Doron Aurbach, Yan Yao
Batteries based on multivalent metals have the potential to meet the future needs of large-scale energy storage, due to the relatively high abundance of elements such as magnesium, calcium, aluminium and zinc in the Earth’s crust. However, the complexity of multivalent metal-ion chemistries has led to rampant confusions, technical challenges, and eventually doubts and uncertainties about the future of these technologies. In this Review, we clarify the key strengths as well as common misconceptions of multivalent metal-based batteries. We then examine the growth behaviour of metal anodes, which is crucial for their safety promises but hitherto unestablished. We further discuss scrutiny of anode efficiency and cathode storage mechanism pertaining to complications arising from electrolyte solutions. Finally, we critically review existing cathode materials and discuss design strategies to enable genuine multivalent …
Show moreSep 2020 • Journal of The Electrochemical Society
Sarah Taragin, Jan L Allen, Lin Ma, Malachi Noked, Marshall A Schroeder
Olivine LiCoPO 4 (LCP) exhibits a rare combination of high theoretical capacity (167 mAh g− 1), excellent thermal stability, and high redox potential (4.8 V vs vs Li/Li+), making it a promising candidate for high voltage lithium batteries. Despite these attractive properties, practical implementation of this electrode chemistry has been limited by stability issues at the cathode-electrolyte interface, including parasitic electrolyte reactions, surface decomposition of the electrode material, and Co dissolution. Carbon coating and substitutions of Co by Fe and other cations improve the performance, however the cycling stability needs further improvement. In an effort to address these issues, we deposited thin, conformal metal oxide surface coatings on substituted LCP powder and investigated the effects of these coatings on the performance of carbon-coated substituted LCP/MCMB graphite full cells with a standard carbonate …
Show moreSep 2020 • Drug Resistance Updates 52, 100704, 2020
Elise Lepeltier, Patricia Rijo, Flavio Rizzolio, Rachela Popovtzer, Vilma Petrikaite, Yehuda G Assaraf, Catherine Passirani
Nanomedicine employs nanotechnologies to develop innovative applications, and more specifically nano-objects in the field of human health, through exploitation of the physical, chemical and biological properties of materials at the nanoscale. The use of nanovehicles capable of transporting and releasing the active therapeutic payload into target cells, particularly in the case of cancer or inflammatory diseases, can also enhance diagnosis. Therefore, nanomedicines improve the benefit/risk ratio of drugs by increasing their bioavailability, selectivity, and efficacy in the target tissue, while reducing the necessary doses and hence diminishing untoward toxicity to healthy tissues. Overcoming multidrug resistance (MDR) to antitumor agents is a central goal of cancer research and therapeutics, making it possible to treat these diseases more accurately and effectively. The adaptability of nanomedicines e.g. modulation of …
Show moreSep 2020 • ACS omega
Elad Hadad, Safra Rudnick-Glick, Igor Grinberg, Michal Kolitz-Domb, Jordan H Chill, Shlomo Margel
RGD sequence is a tripeptide composed of three amino acids: arginine (R), glycine (G), and aspartic acid (D). The RGD peptide has a high affinity to the integrin alpha v beta 3, which is overexpressed on the membrane of many cancer cells and is attracted to areas of angiogenesis. Proteinoids are biodegradable polymers based on amino acids which are formed by bulk thermal step-growth polymerization mechanism. Hollow proteinoid nanoparticles (NPs) may be formed via self-assembly process of the proteinoid polymers. We propose using novel RGD-based proteinoid polymers to manufacture NPs in which the RGD motif is self-incorporated in the proteinoid backbone. Such P(RGD) NPs can act both as a drug carrier (by encapsulation of a desired drug) and as a targeting delivery system. This article presents the synthesis of four RGD proteinoids with different RGD optical configurations, (d) or (l) arginine …
Show moreSep 2020 • arXiv preprint arXiv:2009.14603
Gopi Nath Daptary, Eyal Walach, Efrat Shimshoni, Aviad Frydman
Two-dimensional (2D) materials, composed of single atomic layers, have attracted vast research interest since the breakthrough discovery of graphene. One major benefit of such systems is the simple ability to tune the chemical potential by back-gating, in-principle enabling to vary the Fermi level through the charge neutrality point, thus tuning between electron and hole doping. For 2D Superconductors, this means that one may potentially achieve the strongly-coupled superconducting regime described by Bose Einstein Condensation physics of small bosonic tightly bound electron pairs. Furthermore, it should be possible to access both electron and hole based superconductivity in a single system. However, in most 2D materials, an insulating gap opens up around the charge neutrality point, thus preventing approach to this regime. Graphene is unique in this sense since it is a true semi-metal in which the un-gapped Dirac point is protected by the symmetries. In this work we show that single layer graphene, in which superconducting pairing is induced by proximity to regions of a low density superconductor, can be tuned from hole to electron superconductivity through the strong coupling regime. We study, both experimentally and theoretically, the vicinity of this "Superconducting Dirac point" and find an unusual situation where reflections at interfaces between normal and superconducting regions within the graphene, suppress the conductance and, at the same time, Andreev reflections maintain a large phase breaking length. In addition, the Fermi level can be adjusted so that the momentum in the normal and superconducting regimes perfectly …
Show moreSep 2020 • Cells
Ella Alkalay, Chen Gam Ze Letova Refael, Irit Shoval, Noa Kinor, Ronit Sarid, Yaron Shav-Tal
RNA-binding proteins, particularly splicing factors, localize to sub-nuclear domains termed nuclear speckles. During certain viral infections, as the nucleus fills up with replicating virus compartments, host cell chromatin distribution changes, ending up condensed at the nuclear periphery. In this study we wished to determine the fate of nucleoplasmic RNA-binding proteins and nuclear speckles during the lytic cycle of the Kaposi’s sarcoma associated herpesvirus (KSHV). We found that nuclear speckles became fewer and dramatically larger, localizing at the nuclear periphery, adjacent to the marginalized chromatin. Enlarged nuclear speckles contained splicing factors, whereas other proteins were nucleoplasmically dispersed. Polyadenylated RNA, typically found in nuclear speckles under regular conditions, was also found in foci separated from nuclear speckles in infected cells. Poly (A) foci did not contain lncRNAs known to colocalize with nuclear speckles but contained the poly (A)-binding protein PABPN1. Examination of the localization of spliced viral RNAs revealed that some spliced transcripts could be detected within the nuclear speckles. Since splicing is required for the maturation of certain KSHV transcripts, we suggest that the infected cell does not dismantle nuclear speckles but rearranges their components at the nuclear periphery to possibly serve in splicing and transport of viral RNAs into the cytoplasm. View Full-Text
Show moreSep 2020 • Journal of Solid State Electrochemistry
David Malka, Netanel Shpigel, Ran Attias, Doron Aurbach
This original article contained a mistake.
Show moreSep 2020 • Journal of The Electrochemical Society
Boryann Liaw, Thomas P Barrera, Doron Aurbach
Battery reliability and safety are two key issues critically affecting the sustainability of battery technology and the entire supply chain. Reliability and safety are interrelated and inseparable. In this focus issue, sixty (60) articles have been published online. This is quite an accomplishment for the Journal of The Electrochemical Society, indicative of the importance of this subject matter. We would like to take this opportunity to emphasize the meaning of reliability and safety in a proper context. Reliability, in principle, refers to a cell’s ability to sustain its functionality for the intended use, not only in performance but also in consistency for all aspects of the functions and for resilience in the event of failures. The reliability issues could range from a material’s electrochemical stability, an electrode’s architectural stability, and a cell’s energetic stability under the influences of external stress factors (such as mechanical stresses …
Show moreSep 2020 • Langmuir
Sven Festersen, Benjamin Runge, Christian Koops, Florian Bertram, Ben Ocko, Moshe Deutsch, Bridget M Murphy, Olaf M Magnussen
Detailed in operando studies of electrochemically induced PbBrF deposition at the liquid mercury/liquid electrolyte interface are presented. The nucleation and growth were monitored using time-resolved X-ray diffraction and reflectivity combined with electrochemical measurements, revealing a complex potential-dependent behavior. PbBrF deposition commences at potentials above −0.7 V with the rapid formation of an ultrathin adlayer of one unit cell thickness, on top of which (001)-oriented three-dimensional crystallites are formed. Two potential regimes are identified. At low overpotentials, slow growth of a low surface density film of large crystals is observed. At high overpotentials, crossover to a potential-independent morphology occurs, consisting of a compact PbBrF deposit with a saturation thickness of 25 nm, which forms within a few minutes. This potential behavior can be rationalized by the increasing …
Show moreSep 2020 • Investigative Ophthalmology & Visual Science
Revital Schick, Nairouz Farah, Amos Markus, Alon Korngreen, Yossi Mandel
Purpose: Photoreceptor precursor cells (PRPs) differentiated from human embryonic stem cells 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 AMD. In this work, we studied the electrophysiologic maturation of PRPs throughout the differentiation process.Methods: Human embryonic stem cells were differentiated into PRPs and whole-cell recordings were performed for electrophysiologic characterization at days 0, 30, 60, and 90 along with quantitative PCR analysis to characterize the expression level of various ion channels, which shape the electrophysiologic response. Finally, to characterize the electrically induced calcium currents, we employed calcium imaging (rhod4) to visualize intracellular calcium dynamics in response to electrical activation.Results: Our results revealed an early and steady presence (approximately 100% of responsive cells) of the delayed potassium rectifier current. In contrast, the percentage of cells exhibiting voltage-gated sodium currents increased with maturation (from 0% to almost 90% of responsive cells at 90 days). Moreover, calcium imaging revealed the presence of voltage-gated calcium currents, which play a major role in vision formation. These results were further supported by quantitative PCR analysis, which revealed a significant and continuous (3-to 50-fold) increase in the expression of various voltage-gated channels concomitantly with the increase in the expression of the photoreceptor marker CRX.Conclusions: These results can shed light on the electrophysiologic …
Show moreAug 2020 • SPring-8/SACLA Research Report
A Schori, D Borodin, K Tamasaku, Reis DA, Y Feng, Y Inubushi, M Yabashi, S Shwartz
The purpose of this beamtime was to observe difference-frequency generation of optical radiation from two-color x-ray pulses and to explore the possibility to use it as a method for the study of light matter interactions at atomic scale resolution. The experiment followed a detailed theoretical analysis of the effect [1]. We did not measure difference frequency generation during that beamtime due to technical challenges.
Show moreAug 2020 • Metamaterials, Metadevices, and Metasystems 2020 11460, 114600L, 2020
Tomer Lewi
We present our latest progress in the study of different tunable and active mechanisms in various materials that exhibit large modulation of optical constants and are used to implement active resonators and metasurfaces. We first discuss tuning of infrared Mie-resonant Si and Ge metasurfaces by modulating their free carrier density. We then move to discuss thermo-optic (TO) effects in Si, Ge and InSb and demonstrate tuning of Mie resonances by more than the resonance linewidth. Exploiting the peak TO coefficient of Si near its bandgap, we realize reconfigurable metasurfaces and tunable metafilters. We also show that phase transition materials such as VO2 can be used to implement active devices. We demonstrate electrically tunable Ge on VO2 resonators acting both as amplitude and phase modulators. Finally, we demonstrate ultra-wide dynamic tuning of PbTe meta-atoms. Taking advantage of the …
Show moreAug 2020 • University of Southampton, 2020
Matthew Praeger, Symeon Papazoglou, Amaia Pesquera, Amaia Zerutuza, Adi Levi, Doron Naveh, Ioanna Zergioti, RW Eason, Benjamin Mills
Dataset relating to the journal article 'Laser-Induced Backward Transfer of Monolayer Graphene' , published in Applied Surface Science.
Show moreAug 2020 • The Open Access Journal of Science and Technology
Hagit Aviv
Recently, developments in optical filters have enabled thefacile use of Raman spectroscopy to detect low-frequency vibrational (LFV) modes. We presented a new method for differentiating racemic from enantiopure crystals by using, for the first time, Raman spectroscopy to characterize the LFV modes of crystalline organic materials composed of chiral molecules. The LF-Raman spectra of racemic and enantiopure crystals exhibit a significant variation, which we attribute to different hydrogen-bond networks in the chiral crystal structures. Across a representative set of amino acids, we observed that when comparing racemic versus enantiopure crystals, the available LFV modes and their relative scattering intensity are strong functions of side chain polarity. Thus, LF-Raman can be used as a complementary method to the currently used methods for characterizing crystal’s chirality. The pharmaceutical industry is in need of new techniques to identify the chirality of solids due to regulatory and safety concerns regarding the biological activity of enantiomers. Since we found the LF-Raman spectra of racemic and enantiopure crystals are significantly different, we set out to demonstrate the capabilities of our method for chiral purity investigation. For that we used a model system based on chiral crystals of enantiopure, racemic crystals and their mixtures in various ratios. Using this method, we were able to identify small amounts, as low as 1% w/w, of an enantiomer in racemic crystals. Comparing the achieved sensitivity for enantiomeric excess measurement in chiral crystals to that of circular dichroism and X-ray diffraction measurements showed that LF …
Show moreAug 2020 • Applied Physics Letters
Shubhankar Das, Ariel Zaig, Moty Schultz, Susana Cardoso, Diana C Leitao, Lior Klein
We present a magnetic tunnel junction (MTJ) where its two ferromagnetic layers are in the form of a single ellipse (SE) and two-crossing ellipses (TCEs). The MTJ exhibits four distinct resistance states corresponding to the four remanent states of the TCE structure. Flowing current in an underlying Ta layer generates in the adjacent TCE structure spin–orbit torques, which induce field-free switching of the four-state MTJ between all its resistance states. The demonstrated four-state MTJ is an important step toward fabricating multi-level MTJs with numerous resistance states, which could be important in various spintronics applications, such as multi-level magnetic random access or neuromorphic memory.
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