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Sep 2020 • APL Photonics

Temporal imaging with a high filling factor

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.

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Sep 2020 • Journal of functional biomaterials

Antimicrobial Properties of the Polyaniline Composites against Pseudomonas aeruginosa and Klebsiella pneumoniae

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

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Sep 2020 • PRX Quantum

Quasiprobability distribution for heat fluctuations in the quantum regime

Amikam Levy, Matteo Lostaglio

The standard approach to deriving fluctuation theorems fails to capture the effect of quantum correlation and coherence in the initial state of the system. Here, we overcome this difficulty and derive the heat-exchange-fluctuation theorem in the full quantum regime by showing that the energy exchange between two locally thermal states in the presence of initial quantum correlations is faithfully captured by a quasiprobability distribution. Its negativities, being associated with proofs of contextuality, are proxies of nonclassicality. We discuss the thermodynamic interpretation of negative probabilities and provide heat-flow inequalities that can only be violated in their presence. Remarkably, testing these fully quantum inequalities, at an arbitrary dimension, is no more difficult than testing traditional fluctuation theorems. We test these results on data collected in a recent experiment studying the heat transfer between two …

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Sep 2020 • Langmuir

Nucleation and Growth of PbBrF Crystals at the Liquid Mercury–Electrolyte Interface Studied by Operando X-ray Scattering

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 …

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Sep 2020 • Bioresource technology reports

An efficient method to produce 1, 4-pentanediol from the biomass of the algae Chlorella ohadi with levulinic acid as intermediate

Elena Benisvy-Aharonovich, Anat Zandany, Abed Saady, Yael Kinel-Tahan, Yaron Yehoshua, Aharon Gedanken

Today, the development of innovative methods for production of organic compounds from natural resources is essential topic for many research groups in the worldwide. Levulinic acid is a platform for many important organic processes in the synthesis of natural products, pharmaceuticals, plasticizers, drugs and various other additives. In addition, 1,4-pentanediol which is a product of reduction of levulinic acid, is a valuable raw material in the chemical industry. Here, we report a highly efficient method for the production of levulinic acid from Chlorella ohadi algae using hydrothermal hydrolysis process by using HCl. Our methodology shows that the levulinic acid can be obtained in almost 90% molar yield compared to the glucose in Chlorella ohadi. Finally, we describe a one step reaction for the completely conversion of levulinic acid into 1,4-pentadiol in water using S. cerevisiae yeast as a catalyst.

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Sep 2020 • Journal of Biophotonics 13 (9), e202000158, 2020

Fluorescence for biological logic gates

EA Barnoy, R Popovtzer, D Fixler

Biological logic gates are smart probes able to respond to biological conditions in behaviors similar to computer logic gates, and they pose a promising challenge for modern medicine. Researchers are creating many kinds of smart nanostructures that can respond to various biological parameters such as pH, ion presence, and enzyme activity. Each of these conditions alone might be interesting in a biological sense, but their interactions are what define specific disease conditions. Researchers over the past few decades have developed a plethora of stimuli‐responsive nanodevices, from activatable fluorescent probes to DNA origami nanomachines, many explicitly defining logic operations. Whereas many smart configurations have been explored, in this review we focus on logic operations actuated through fluorescent signals. We discuss the applicability of fluorescence as a means of logic gate implementation …

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Sep 2020 • New Journal of Physics

Single-atom heat engine as a sensitive thermal probe

Amikam Levy, Moritz Göb, Bo Deng, Kilian Singer, Erik Torrontegui, Daqing Wang

We propose employing a quantum heat engine as a sensitive probe for thermal baths. In particular, we study a single-atom Otto engine operating in an open thermodynamic cycle. Owing to its cyclic nature, the engine is capable of translating small temperature differences between two baths into a macroscopic oscillation in a flywheel. We present analytical and numerical modeling of the quantum dynamics of the engine and estimate it to be capable of detecting temperature differences as small as 2 μK. This sensitivity can be further improved by utilizing quantum resources such as squeezing of the ion motion. The proposed scheme does not require quantum state initialization and is able to detect small temperature differences in a wide range of base temperatures.

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Sep 2020 • EMBO molecular medicine

A Parkinson's disease Circ RNA s resource reveals a link between circ SLC 8A1 and oxidative stress

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 …

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Sep 2020 • Advanced Functional Materials

Rationally Designed Vanadium Pentoxide as High Capacity Insertion Material for Mg‐Ion

Ayan Mukherjee, Sarah Taragin, Hagit Aviv, Ilana Perelshtein, Malachi Noked

Owing to high energy density and economic viability, rechargeable Mg batteries are considered alternatives to lithium ion batteries. However besides the chevrel phase, none of the conventional inorganic cathode materials demonstrate reversible intercalation/deintercalation of Mg+2 ions in an anhydrous electrolyte system. The lack of high voltage and high capacity cathode frustrates the realization of Mg batteries. Previous studies indicate that vanadium pentoxide (V2O5) has the potential to reversibly insert/extract Mg ions. However, many attempts to utilize V2O5 demonstrate limited electrochemical response, due to hindered Mg ion mobility in solid. Here, monodispersed spherical V2O5 with a hierarchical architecture is rationally designed, through a facile and scalable approach. The V2O5 spheres exhibit initial discharge capacity of 225 mA h g−1 which stabilizes at ≈190 mA h g−1 at 10 mA g−1, much higher …

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Sep 2020 • Developmental Neurobiology

SEM/FIB Imaging for Studying Neural Interfaces

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 …

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Sep 2020 • ACS omega

Synthesis and Characterization of Poly (RGD) Proteinoid Polymers and NIR Fluorescent Nanoparticles of Optimal d, l-Configuration for Drug-Delivery Applications—In Vitro Study

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 …

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Sep 2020 • Drug Resistance Updates 52, 100704, 2020

Nanomedicine to target multidrug resistant tumors

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 …

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Sep 2020 • Advanced Composites and Hybrid Materials

Surfactant-assisted cerium oxide and its catalytic activity towards Fenton process for non-degradable dye

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 …

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Sep 2020 • Investigative Ophthalmology & Visual Science

Electrophysiologic Characterization of Developing Human Embryonic Stem Cell-Derived Photoreceptor Precursors

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 …

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Sep 2020 • Journal of The Electrochemical Society

Stabilization of Lithium Cobalt Phosphate Cathodes via Artificial Interphases

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 …

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Sep 2020 • Nature Energy 5 (9), 646-656, 2020

Current status and future directions of multivalent metal-ion batteries

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 …

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Aug 2020 • Frontiers in microbiology

TrypOx, a Novel Eukaryotic Homolog of the Redox-Regulated Chaperone Hsp33 in Trypanosoma brucei

Samar Aramin, Rosi Fassler, Vaibhav Chikne, Mor Goldenberg, Tal Arian, Liat Kolet Eliaz, Oded Rimon, Oren Ram, Shulamit Michaeli, Dana Reichmann

ATP-independent chaperones are widespread across all domains of life and serve as the first line of defense during protein unfolding stresses. One of the known crucial chaperones for bacterial survival in a hostile environment (e.g. heat and oxidative stress) is the highly conserved, redox-regulated ATP-independent bacterial chaperone Hsp33. Using a bioinformatic analysis, we describe novel eukaryotic homologues of Hsp33 identified in eukaryotic pathogens belonging to the kinetoplastids, a family responsible for lethal human diseases such as Chagas disease as caused by Trypanosoma cruzi, African sleeping sickness caused by Trypanosoma brucei spp, and leishmaniasis pathologies delivered by various Leishmania species. During their pathogenic life cycle, kinetoplastids need to cope with elevated temperatures and oxidative stress, the same conditions which convert Hsp33 into a powerful chaperone in bacteria, thus preventing aggregation of a wide range of misfolded proteins. Here we focused on a functional characterization of the Hsp33 homologue in one of the members of the kinetoplastid family, T. brucei, (Tb927.6.2630), which we have named TrypOx. RNAi silencing of TrypOx led to a significant decrease in the survival of T.brucei under mild oxidative stress conditions, implying a protective role of TrypOx during the Trypanosomes growth. We then adopted a proteomics-driven approach to investigate the role of TrypOx in defining the oxidative stress response. Depletion of TrypOx significantly altered the abundance of proteins mediating redox homeostasis, linking TrypOx with the antioxidant system. Using biochemical …

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Aug 2020 • Israel Journal of Chemistry 60 (8-9), 850-862, 2020

Review of Computational Studies of NCM Cathode Materials for Li‐ion Batteries

Arup Chakraborty, Sooraj Kunnikuruvan, Mudit Dixit, Dan T Major

Lithium‐ion based rechargeable batteries are considered among the most promising battery technologies because of the high energy‐ and power‐densities of these electrochemical devices. Computational studies on lithium ion batteries (LIBs) facilitate rationalization and prediction of many important experimentally observed properties, including atomic structure, thermal stability, electronic structure, ion diffusion pathways, equilibrium cell voltage, electrochemical activity, and surface behavior of electrode materials. In recent years, Ni, Co and Mn‐based (NCM) layered transition metal oxide positive electrode materials (LiNi1‐x‐yCoxMnyO2) have shown tremendous promise for high‐energy density LIBs, and these NCM‐based batteries are effectively commercialized. Here, we present an overview of recent theoretical work performed using first principles density functional theory on these layered cathode materials …

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Aug 2020 • ACS omega

Two orders of magnitude boost in the detection limit of droplet-based micro-magnetofluidics with planar hall effect sensors

Julian Schütt, Rico Illing, Oleksii Volkov, Tobias Kosub, Pablo Nicolás Granell, Hariharan Nhalil, Jürgen Fassbender, Lior Klein, Asaf Grosz, Denys Makarov

Magnetofluidics is a dynamic research field, which requires novel sensor solutions to boost the detection limit of tiny quantities of magnetized objects. Here, we present a sensing strategy relying on planar Hall effect sensors in droplet-based micro-magnetofluidics for the detection of a multiphase liquid flow, i.e., superparamagnetic aqueous droplets in an oil carrier phase. The high resolution of the sensor allows the detection of nanoliter-sized superparamagnetic droplets with a concentration of 0.58 mg/cm3, even when they are biased in a geomagnetic field only. The limit of detection can be boosted another order of magnitude, reaching 0.04 mg/cm3 (1.4 million particles in a single 100 nL droplet) when a magnetic field of 5 mT is applied to bias the droplets. With this performance, our sensing platform outperforms the state-of-the-art solutions in droplet-based micro-magnetofluidics by a factor of 100. This allows us …

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Aug 2020 • Physics

Modeling Energy Transfer in Quantum Thermal Machines

Amikam Levy, Wenjie Dou

Figure 1: In a simple thermal machine, a system S is coupled to two reservoirs with different chemical potentials and temperatures. As a result of the chemical-potential difference, currents of particles and energy are sustained through the system.

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Aug 2020 • ACS Applied Energy Materials

Carbon-supported PtNi nanocrystals for alkaline oxygen reduction and evolution reactions: electrochemical activity and durability upon accelerated stress tests

Victor Shokhen, Melina Zysler, Meital Shviro, David Zitoun, Marian Chatenet

The PtNi catalyst is among the most active electrocatalysts for the oxygen reduction reaction, but its stability in operation is uncertain. Intuitively, alkaline environments lead to milder degradations than acidic ones, although carbon-supported Pt-group metal nanoparticles are particularly degraded even in dilute alkaline electrolytes. To date, PtNi catalyst durability has not been characterized for alkaline oxygen reduction and evolution reactions (ORR and OER). Herein, carbon-supported shape-controlled PtNi catalysts were compared in terms of activity and durability during alkaline ORR and OER. The PtNi catalysts are shape-controlled Pt-rich alloy, Ni-rich alloy, and Pt core/Ni shell (Pt@Ni) nanoparticles synthesized on Vulcan XC72R carbon. Their morphology and composition were evaluated by identical-location transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction pre- and …

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