BINA

The exotic physics emerging in non-Hermitian systems with balanced distributions of gain and loss has recently drawn a great deal of attention. These systems exhibit phase transitions and exceptional point singularities in their spectra, at which eigen-values and eigen-modes coalesce and the overall dimensionality is reduced. So far, these principles have been implemented at the expense of precise fabrication and tuning requirements, involving tailored nano-structured devices with controlled optical gain and loss. In this work, anti-parity-time symmetric phase transitions and exceptional point singularities are demonstrated in a single strand of single-mode telecommunication fibre, using a setup consisting of off-the-shelf components. Two propagating signals are amplified and coupled through stimulated Brillouin scattering, enabling exquisite control over the interaction-governing non-Hermitian parameters …

We investigate the overdamped Langevin motion for particles in a potential well that is asymptotically flat. When the potential well is deep as compared to the temperature, physical observables, like the mean square displacement, are essentially time-independent over a long time interval, the stagnation epoch. However, the standard Boltzmann-Gibbs (BG) distribution is non-normalizable, given that the usual partition function is divergent. For this regime, we have previously shown that a regularization of BG statistics allows for the prediction of the values of dynamical and thermodynamical observables in the non-normalizable quasi-equilibrium state. In this work, based on the eigenfunction expansion of the time-dependent solution of the associated Fokker–Planck equation with free boundary conditions, we obtain an approximate time-independent solution of the BG form, being valid for times that are long, but still short as compared to the exponentially large escape time. The escaped particles follow a general free-particle statistics, where the solution is an error function, which is shifted due to the initial struggle to overcome the potential well. With the eigenfunction solution of the Fokker–Planck equation in hand, we show the validity of the regularized BG statistics and how it perfectly describes the time-independent regime though the quasi-stationary state is non-normalizable.

Metallic thin films with nanocavity arrays provide ideal platforms for plasmonics, non-linear optics, surface chemistry and corresponding applications. A general understanding of electromagnetic (EM) field distributions is needed for further creation, manipulation and designation of near-field enhancements. Herein, we study the distribution of plasmonic hot spots over Ag thin films with triangular nanocavities in hexagonal arrays with a variable of lattice parameters. We propose that the concentration and interference of surface plasmon polaritons (SPP) dominates the distribution of plasmonic hot spots. The localized surface plasmonic resonance (LSPR) at nanocavities excites SPPs to propagate on the thin film, whose concentration and interference lead to an extremely strong near-field enhancement at the surface of the thin film, the location of which can also be termed as plasmonic hot spot. For this model, the …

Studying the electrical activity in single cells and in local circuits of excitable cells, like neurons, requires an easy to use and high throughput methodology that enables the measurement of membrane potential. Studying the electrical properties in particular sub-compartments of neurons, or in a specific type of neurons produces additional complexity. An optical voltage-imaging technique that allows high spatial and temporal resolution could be an ideal solution. However, most of the valid voltage imaging techniques are nonspecific; The ones that are more site-directed require much pre-work and specific adaptations in addition to other disadvantages. Here, a new technique for membrane voltage imaging, based on FRET between fluorescent polystyrene (FPS) beads and Dipicrylamine (DPA) is explored. Not only fluorescent intensity is demonstrated to be correlated with membrane potential, but more importantly, single particle voltage detection is demonstrated. Among other advantages, FPS beads can be synthesized with functional surface groups, and be further targeted to specific proteins via conjugation of recognition molecules. Therefore, FPS beads, in the presence of DPA, constitute single-particle detectors for membrane voltage, with a potential to be localized to specific membrane compartments. This new and accessible platform for targeted optical voltage imaging may further elucidate the mechanisms of neuronal electrical activity.

We present a detailed description of the experiment realizing for the first time a protective measurement, a novel measurement protocol which combines weak interactions with a “protection mechanism” preserving the measured state coherence during the whole measurement process. Furthermore, protective measurement allows finding the expectation value of an observable, ie, an inherently statistical quantity, by measuring a single particle, without the need for any statistics. This peculiar property, in sharp contrast to the framework of traditional (projective) quantum measurement, might constitute a groundbreaking advance for several quantum technology related fields. View Full-Text

This paper aims to characterize the wear behavior of hydrogel constructs designed for human articular cartilage replacement. To this purpose, poly (ethylene glycol) diacrylate (PEGDA) 10% w/v and gellan gum (GG) 1.5% w/v were used to reproduce the superior (SUP) cartilage layer and PEGDA 15% w/v and GG 1.5% w/v were used to reproduce the deep (DEEP) cartilage layer, with or without graphene oxide (GO). These materials (SUP and DEEP) were analyzed alone and in combination to mimic the zonal architecture of human articular cartilage. The developed constructs were tested using a four-station displacement control knee joint simulator under bovine calf serum. Roughness and micro-computer tomography (µ-CT) measurements evidenced that the hydrogels with 10% w/v of PEGDA showed a worse behavior both in terms of roughness increase and loss of uniformly distributed density than 15% w/v of PEGDA. The simultaneous presence of GO and 15% w/v PEGDA contributed to keeping the hydrogel construct’s characteristics. The Raman spectra of the control samples showed the presence of unreacted C= C bonds in all the hydrogels. The degree of crosslinking increased along the series SUP< DEEP+ SUP< DEEP without GO. The Raman spectra of the tested hydrogels showed the loss of diacrylate groups in all the samples, due to the washout of unreacted PEGDA in bovine calf serum aqueous environment. The loss decreased along the series SUP> DEEP+ SUP> DEEP, further confirming that the degree of photo-crosslinking of the starting materials plays a key role in determining their wear behavior. μ-CT and Raman …

A detailed investigation is presented for the solvent-free mechanochemical synthesis of zinc oxide nanoparticles from ε-Zn (OH) 2 crystals by high-energy ball milling. Only a few works have ever explored the dry synthetic route from ε-Zn (OH) 2 to ZnO. The milling process of ε-Zn (OH) 2 was done in ambient conditions with a 1: 100 powder/ball mass ratio, and it produced uniform ZnO nanoparticles with sizes of 10–30 nm, based on the milling duration. The process was carefully monitored and the effect of the milling duration on the powder composition, nanoparticle size and strain, optical properties, aggregate size, and material activity was examined using XRD, TEM, DLS, UV-Vis, and FTIR. The mechanism for the transformation of ε-Zn (OH) 2 to ZnO was studied by TGA and XPS analysis. The study gave proof for a reaction mechanism starting with a phase transition of crystalline ε-Zn (OH) 2 to amorphous Zn (OH) 2, followed by decomposition to ZnO and water. To the best of our knowledge, this mechanochemical approach for synthesizing ZnO from ε-Zn (OH) 2 is completely novel. ε-Zn (OH) 2 crystals are very easy to obtain, and the milling process is done in ambient conditions; therefore, this work provides a simple, cheap, and solvent-free way to produce ZnO nanoparticles in dry conditions. We believe that this study could help to shed some light on the solvent-free transition from ε-Zn (OH) 2 to ZnO and that it could offer a new synthetic route for synthesizing ZnO nanoparticles. View Full-Text

The need for tissue contact makes photoacoustic imaging not applicable for special medical applications like wound imaging, endoscopy, or laser surgery. An easy, stable, and contact-free sensing technique might thus help to broaden the applications of the medical imaging modality. In this work, it is demonstrated for the first time that remote photoacoustic sensing by speckle analysis can be performed in the MHz sampling range by tracking a single speckle using a four quadrant photo-detector. A single speckle, which is created by self-interference of surface back-reflection, is temporally analyzed using this photo-detector. Phantoms and skin samples are measured in transmission and reflection mode. The potential for miniaturization for endoscopic application is demonstrated by fiber bundle measurements. In addition, sensing parameters are discussed. Photoacoustic sensing in the MHz sampling range by single speckle analysis with the four quadrant detector is successfully demonstrated. Furthermore, the endoscopic applicability is proven, and the sensing parameters are convenient for photoacoustic sensing. It can be concluded that a single speckle contains all the relevant information for remote photoacoustic signal detection. Single speckle sensing is therefore an easy, robust, contact-free photoacoustic detection technique and holds the potential for economical, ultra-fast photoacoustic sensing. The new detection technique might thus help to broaden the field of photoacoustic imaging applications in the future. View Full-Text

When cooled down, emulsion droplets stabilized by a frozen interface of alkane molecules and surfactants have been observed to undergo a spectacular sequence of morphological transformations: from spheres to faceted liquid icosahedra, down to flattened liquid platelets. While generally ascribed to the interplay between the elasticity of the frozen interface and surface tension, the physical mechanisms underpinning these transitions have remained elusive, despite different theoretical pictures having been proposed in recent years. In this Letter, we introduce a comprehensive mechanical model of morphing emulsion droplets, which quantitatively accounts for various experimental observations, including the size scaling behavior of the faceting transition. Our analysis highlights the role of gravity and the spontaneous curvature of the frozen interface in determining the specific transition pathway.

The purpose of this paper is to suggest frontier inter‐disciplinary research directions that can be considered as important horizons of modern electrochemistry in the field of energy storage and conversion. We selected several topics that call for advancements in solid‐state, interfacial, analytical and energy‐related electrochemical science. A dramatic improvement in the performance of energy storage and conversion devices is needed to meet the urgent demands of our society. Significantly more efficient devices are needed to meet two major challenges: electro‐mobility, namely electrochemical propulsion of electric vehicles, and the ability to store and convert large quantities of energy generated from sustainable sources such as sun and wind. We suggest promotion of breakthroughs in several important directions. The examples chosen include: Development of novel in‐situ methodologies for design and testing …

While many studies have been devoted to the development of new active materials for Na-ion aqueous batteries, much less attention has been given to the binders and other passive components, which largely determine the battery performance. This study demonstrates a beneficial use of MXene as a highly efficient binder for Na-ion anodes operating in aqueous electrolyte solutions. The high conductivity of 2D titanium carbide (Ti3C2Tx; T = terminal groups, mostly –OH, 0 < x < 2) denoted as MXene and the strong attractive interactions between its sheets and active material particles enable their effective encapsulation providing electronically conductive paths, fast ion transfer, and capacitive contribution to the stored charge. Using highly concentrated NaClO4 as an electrolyte solution providing a stable potential operation window, successful integration of NaTi2(PO3)4 (NTP) particles with MXene as a binding …

INTRODUCTION Cells and tissues are made up of diverse molecular building blocks, organized with nanoscale precision over extended length scales. Newly developed techniques that enable highly multiplexed, nanoscale, and subcellular analysis of such systems are required. Although much progress has been made on methods for multiplexed RNA imaging, these methods have been limited in their spatial precision, especially in the context of three-dimensional systems such as tissues. Because of this limitation, interrogation of tissues has been performed with either high spatial resolution or high molecular multiplexing capacity, but not both.RATIONALE We reasoned that physically expanding specimens by adapting expansion microscopy could help support spatially precise in situ sequencing. The physical expansion of specimens provides two benefits: First, it enables ordinary microscopes to achieve …

Pt–Ni nanoparticles (NPs) are used as electrocatalysts toward the oxygen reduction reaction due to their high mass activity. However, degradation processes at high potential under the acidic conditions of proton exchange membrane fuel cells delay their massive implementation. The model presented here facilitates understanding of the corrosion by clearing variables related to the electrochemical measurement (non-equilibrium conditions and complex system) and focusing on the gradual etching of Ni via two-phase Ni(II) transfer treatment promoted by chelating agents (CAs). We synthesized Pt–Ni/C octahedral NPs and then used six chemically different CAs as corrosion agents for Ni. The corrosion yielded concave octahedral and hexapod NPs. Amine-rich CA treatment results in particle detachment from the carbon substrates, while carboxylic-rich CA treatment preserves the carbon–particle bond. We correlate …

Extracellular vesicles (EVs) isolated from pathogens mediate communication between parasites and their hosts under a variety of physiological and pathological conditions. EVs deliver cell-free messages via a transfer of RNA, proteins, and even DNA to modulate and induce inflammation and to control the host infection process. EVs can provide valuable information on how a pathogen sends messages to other pathogens and hosts (Torrecilhas et al., 2012; Campos et al., 2015; Ofir-Birin and Regev-Rudzki, 2019; Torrecilhas et al. 2020). This Research Topic provides an overview of the mechanism of EV-mediated communication between hosts and viruses, parasites, and fungi. This Research Topic consists of 17 papers, including 8 reviews and 9 original papers. Several studies on this topic assessed the effects of EVs on the interactions between pathogens and hosts, and the mechanisms of EV-mediated communication between hosts and pathogens were also addressed. The first original article published in this Frontiers in Cellular and Infection Microbiology Parasite and Host issue is from Duguet’s group (Duguet et al.). They showed that EVs isolated from Caenorhabditis elegans contain microRNAs and small regulators that affect biological processes and comment on their role in host-nematode communication. Parasite-derived miRNAs regulate host immune system mRNAs.The paper by Zhang et al. discusses how Echinococcus granulosus protoscoleces (PSCs) and hydatid cysts release EVs that are exosome-like based on size and morphology. The authors analyzed the miRNA, circRNA, and lncRNA profiles of the 20 most abundant …

BackgroundTranslation of nanomedical developments into clinical application is receiving an increasing interest. However, its use for oral squamous cell carcinoma (OSCC) diagnosis remains limited. We present an advanced nanophotonic method for oral cancer detection, based on diffusion reflection (DR) measurements of gold-nanorods bio-conjugated to anti-epidermal growth factor receptor (C-GNRs) specifically attached to OSCC cells.ObjectiveTo investigate in a rat model of oral carcinogenesis the targeting potential of C-GNRs to OSCC by using the DR optical method.Materials and MethodsOSCC was induced by the carcinogen 4-nitroquinoline-N-oxide (4NQO). C-GNRs were introduced locally and systemically and DR measurements were recorded from the surface of the rat tongue following illumination with red laser beam. Rats were divided into experimental and control groups. The results were …

Aqueous salt batteries with high concentration of salt or water in salt aqueous systems have received considerable attention with focus on improving working voltage range and energy density. Here, the effect of concentration on electrochemical performance and stability of tunnel-type Na0.44MnO2 (NMO) cathode and organic polyimide (PI) derivative as an anode was studied. High capacity retention and 100% coulombic efficiency are shown for NMO/PI full cell in saturated NaClO4 electrolyte. A high stable capacity of 115 mAh/g was achieved for the PI anode material, and the full cell showed stable capacity of 41 mAh/g at 2C rate for 430 cycles (calculated for the weight of NMO cathode). Even at fast 5C rate, a discharge capacity of 33 mAh/g was maintained for 2,400 prolonged cycles with nearly 100% efficiency. The full cell device can achieve an average voltage of 1 V with energy density of 24 Wh/kg. This study highlights concentrated sodium perchlorate as a promising electrolyte solution for stabilization of electrodes and enhancement of electrochemical performance in aqueous media.

Following A-to-I editing of double-stranded RNA (dsRNA) molecules, sequencing reactions interpret the edited inosine (I) as guanosine (G). For this reason, current methods to detect A-to-I editing sites work to align RNA sequences to their reference DNA sequence in order to reveal A-to-G mismatches. However, areas with heavily edited reads produce dense clusters of A-to-G mismatches that hinder alignment, and complicate correct identification of the sites. The presented approach employs prudent alignment and examination of excessive mismatch events, enabling high-accuracy detection of hyper-edited reads and sites.

Long–range structures and dynamics are central to coordination chemistry, yet are hard to identify experimentally. By combining polarized low-frequency Raman spectroscopy with single crystal XRD to study barium nitrilotriacetate, a metal–organic coordination polymer and a useful pyrolysis precursor, we could assign Raman peaks experimentally to layer shear motions and perpendicular hydrogen bond vibrations. These directional long–range interactions further determined the preferred fracture directions during crystallization, establishing an important link between structural motifs in the precursor, and the porosity of the carbon it yields upon pyrolysis.

Correction for ‘Thiadiazole containing N- and S-rich highly ordered periodic mesoporous organosilica for efficient removal of Hg(II) from polluted water’ by Asim Baumik et al., Chem. Commun., 2020, 56, 3963–3966, DOI 10.1039/D0CC00407C.

Interferometry with Bose-Einstein Condensates in Microgravity H. Müntinga, H. Ahlers, M. Krutzik, A. Wenzlawski, S. Arnold, D. Becker, K. Bongs, H. Dittus, H. Duncker, N. Gaaloul, C. Gherasim, E. Giese, C. Grzeschik, TW Hänsch, O. Hellmig, W. Herr, S. Herrmann, E. Kajari,10, S. Kleinert, C. Lämmerzahl, W. Lewoczko-Adamczyk, J. Malcolm, N. Meyer, R. Nolte, A. Peters, M. Popp, J. Reichel, A. Roura, J. Rudolph, M. Schiemangk, M. Schneider, ST Seidel, K. Sengstock, V. Tamma, T. Valenzuela, A. Vogel, R. Walser, T. Wendrich, P. Windpassinger, W. Zeller, T. van Zoest, W. Ertmer, WP Schleich, and EM Rasel Phys. Rev. Lett. 110, 093602 (2013) … Tripartite nonlocality and continuous-variable entanglement in thermal states of trapped ions J. Li, T. Fogarty, C. Cormick, J. Goold, Th. Busch, and M. Paternostro Phys. Rev. A 84, 022321 (2011) … Frühere Veröffentlichungen der Gruppenmitglieder …