BINA

The formation and growth of the Li2O2 discharge product impacts the reversibility of the oxygen evolution and reduction reactions in Li-O2 batteries which may lead to a shorter cycle life. A clear understanding of the surface reactions and the growth mechanism of Li2O2 requires probing dynamic changes on the surface of the positive electrodes in situ during the discharge of a Li-O2 battery. To investigate this, we establish an experimental system by adopting a multi-beam optical sensor (MOS) and developing a custom-made battery cell. First, the accuracy and reliability of the system was demonstrated by analyzing the stress accumulation on the Au negative electrode during Li plating/stripping, and the results were consistent with an earlier single-beam scanning deflectometry report. Then, the Li-O2 battery was discharged in LiNO3 in diglyme electrolyte by applying either linear sweep voltammetry or by applying …

The process of sex determination involves the differentiation of an initially bipotential gonad into either a testis or an ovary. This remarkable process, driven by sex chromosomes in mammals, is first initiated within a somatic cell population called the supporting cell precursors. Once these differentiate into either Sertoli or granulosa cells, they instruct and direct other bipotential cell populations in the gonad, including other somatic progenitors but also the germ cells, to acquire the male or female path.Much of the study in the last 3 decades has been focused towards identifying and understanding the function of many pro-testicular versus pro-ovarian factors involved in this process. Most of these are transcription factors and signalling pathway components expressed in various cell populations, but mostly in Sertoli and granulosa cells, which constitute the driving force of gonad differentiation. Human genetics studies of …

Significance: Numerous optical imaging and spectroscopy techniques are used to study the tissue-optical properties; the majority of them are limited in information regarding the penetration depth. A simple, safe, easily applicable diagnostic technique is required to get deeper tissue information in a multilayer structure. Aim: A fiber-based diffuse reflectance (DR) technique is used to extract and quantify the bottom layer absorption coefficients in two-layer (2L) tissue-mimicking solid phantoms. We determine the Indian black ink concentrations in a deep-hidden layer that is sandwiched between agar and silicone-based phantom layers. Approach: A fiber-based DR experiment was performed to study the optical properties of the tissue at higher penetration depth, with different fiber core diameters and a constant numerical aperture (0.5 NA). The optimal core diameter of the fiber was chosen by measuring solid phantoms …

Cancer is a leading cause of death with rates expected to grow with life expectancy. Among leading treatments, cisplatin, widely used to combat cancer, suffers from low stability and selectivity. Here, we covalently conjugated an analog of cisplatin to biocompatible polydopamine nanoparticles (PDA-NPs) to increase both properties. Dynamic light scattering and electron microscopy studies suggest that the platinum-conjugated PDA particles (Pt–PDA-NPs) are monodispersed and spherical with a diameter of about 200 nm with platinum atoms mostly in the shell. Particles were also characterized with inductively coupled plasma mass atomic emission spectroscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy to determine the localization and amount of Pt atoms. The chelated metal did not leach from the conjugated particles under normal physiological conditions, while it was released …

Coal is intensively used worldwide as a main fuel source. However, it may undergo oxidation processes [i.e., low-temperature oxidation (LTO)] when stored under an air atmosphere in piles post-mining at low temperatures ranging from 300 to 425 K, specifically, a surface gas/solid reaction with molecular oxygen. Therefore, it is of major importance to prevent or appreciably slow down such reactions, which result in a loss in the energy content (calorific value) of coal. Previously, we showed that radicals are formed during the LTO process. In this work, the dependence of radical formation on coal rank as a function of heating (temperature) and the presence of oxygen gas were studied using electron paramagnetic resonance spectroscopy. It was shown that lignite coals are more sensitive than bituminous coals to the atmospheric environment (i.e., molecular oxygen and nitrogen content) and to temperature, as …

Copper is a trace element vital to many cellular functions. Yet its abnormal levels are toxic to cells, provoking a variety of severe diseases. The high affinity Copper Transporter 1 (CTR1), being the main in-cell copper (Cu (I)) entry route, tightly regulates its cellular uptake via a still elusive mechanism. Here, all-atoms simulations unlock the molecular terms of Cu (I) transport in eukaryotes disclosing that the two Methionine triads, forming the selectivity filter, play an unprecedented dual role both enabling selective Cu (I) transport and regulating its uptake-rate thanks to an intimate coupling between the conformational plasticity of their bulky side chains and the number of bound Cu (I) ions. Namely, the Met residues act as a gate reducing the Cu (I) import-rate when two ions simultaneously bind to CTR1. This may represent an elegant autoregulatory mechanism through which CTR1 protects the cells from excessively high, and hence toxic, in-cell Cu (I) levels. Overall, these outcomes resolve fundamental questions in CTR1 biology and open new windows of opportunity to tackle diseases associated with an imbalanced copper uptake.

Sunlight-driven photocatalysis is an environmentally friendly approach to solve ecological issues. The development of simple yet sufficiently stable photocatalytic materials capable of responding to the full-spectrum light remains challenging. Here, we demonstrate the phase transformations of bulk copper sulfides from digenite (Cu9S5) to djurleite (Cu1.97S) and low chalcocite (Cu2S) by the reactive thermal annealing during ambient pressure chemical vapor deposition, followed by their top-down exfoliation. Using multiple techniques, we confirm that monoclinic Cu2S is primarily formed at higher temperatures or greater reaction times and using a reducing atmosphere. We measured the average thickness to be approximately 4 nm for the exfoliated flakes with relatively large lateral sizes of up to 10 μm. We tested the three phases of bulk copper sulfides and their exfoliated forms as photocatalysts for dye degradation …

In this paper, ptychographic phase microscopy (PPM) with digital illumination addressing via a digital micromirror device (DMD) was demonstrated. A moving circular pattern is sequentially lighted up by a DMD and projected on the sample for illumination stepping, and a CCD camera records the generated diffraction patterns. Then, the quantitative phase distribution of the sample can be reconstructed from the diffraction patterns by using an iterative algorithm. Compared with conventional PPM approaches, this method has a fundamentally enhanced imaging speed due to the usage of the digital scan to replace the conventional mechanical scan. Furthermore, parallelized illumination strategy, which loads multiple pupils to DMD simultaneously, is used to further improve the imaging speed to 0.8 s per phase image. We envisage that this method will contribute to high-contrast, quantitative phase imaging of …

In this introduction we provide an overview of the papers that were accepted for publication in the special issue on light detection and ranging (lidar). Four of the papers were published in JOSA A, and four were published in JOSA B. They represent different aspects of this important and fast-growing field while showing the relevant state-of-the-art achievements currently existing in the field of lidars in the world of science and engineering.

The Cover Feature shows the electrochemical performance of 25 μm AZ31 alloy as anode, in a full magnesium cell with Chevrel phase as cathode, in 0.25 m APC as electrolyte. The use of low concentration of foreign elements in magnesium AZ31 alloy (Al 3%, Zn 1%), increases the mechanical strength and ductility along with resistance to corrosion and weldability, giving similar electrochemical performance compared to 100 μm pure Magnesium metal foil. More information can be found in the Full Paper by A. Maddegalla et al.

Herein, a systematic surface modification approach via double gas (SO2 and NH3) treatment at elevated temperatures is described, aimed to achieve a stable electrochemical performance of Li and Mn-rich NCM cathode materials of a typical composition 0.33Li2MnO3·0.67LiNi0.4Co0.2Mn0.4O2 (HE-NCM). Partial surface reduction of Mn4+ and the formation of a modified interface comprising Li-ions conductive nano-sized Li2SO4/Li2SO3 phases are established. Li-coin cells’ prolonged cycling performance demonstrated significantly improved capacity retention (∼2.2 times higher than untreated cathode materials) for the double-gas-treated cathodes after 400 cycles at a 1.0 C rate. Stable discharge potential and lower voltage hysteresis during cycling were also achieved through the double gas treatment. Comparative electrochemical studies in full-pouch cells [vs. Graphite anodes] also demonstrated considerably …

This review summarizes the recent advances in the enantioselective separation of small molecules using biomolecules/macromolecules built up by natural inherent chiral moieties. Although different kinds of chiral selectors are known to date, the microspheres based on biomolecules have received paramount importance in view of their green synthesis, selective and sensitive separation of enantiomers from the racemic mixture. Direct separation of enantiomers devoid of using high-performance liquid chromatography adds to the elegance of this approach. We have covered the preparation of various biomolecules spheres by different methods. The enantiomeric separation of amino acids, drugs and other racemates and the underlying plausible mechanism is discussed.

In the presence of interactions, electrons in condensed-matter systems can behave hydrodynamically, exhibiting phenomena associated with classical fluids, such as vortices and Poiseuille flow–. In most conductors, electron–electron interactions are minimized by screening effects, hindering the search for hydrodynamic materials; however, recently, a class of semimetals has been reported to exhibit prominent interactions,. Here we study the current flow in the layered semimetal tungsten ditelluride by imaging the local magnetic field using a nitrogen-vacancy defect in a diamond. We image the spatial current profile within three-dimensional tungsten ditelluride and find that it exhibits non-uniform current density, indicating hydrodynamic flow. Our temperature-resolved current profile measurements reveal a non-monotonic temperature dependence, with the strongest hydrodynamic effects at approximately 20 K. We …

Extracting the theoretically high capacity of LiCoO2 (LCO) is desirable for enhancing the energy density of currently used lithium‐ion batteries (LIBs) for portable devices. The bottleneck for exhibiting the high capacity is associated with the limited cut‐off positive voltages beyond which degradation of electrode/electrolyte takes place. In this work, we apply hybrid organic‐inorganic alucone thin film grown directly on LCO by a molecular layer deposition (MLD) method, using sequential exposure to Al‐based and organic‐based precursors. The alucone thin films enabled the high voltage operation of the LCO cathode (>4.5 V), acting as a protection layer. Electrochemical studies proved that alucone coated LCO show enhanced electrochemical performances with improved cycling stability and enhanced specific capacity, relative to uncoated LCO. Amongst the studied films, 10 nm ethylene glycol/Al coated LCO have …

This work is part of ongoing and systematic investigations by our groups on the synthesis, electrochemical behavior, structural investigations, and computational modeling of the Ni-rich materials Li[NixCoyMnz]O2 (x+y+z=1; x≥0.8) for advanced lithium-ion batteries. This study focuses on the LiNi0.85Co0.10Mn0.05O2 (NCM85) material and its improvement upon doping with B3+ cations. The data demonstrate the substantial improvement of the doped electrodes in terms of cycling performance, lower voltage hysteresis and reduced self-discharge upon high temperature storage. The electronic structure of the undoped and B-doped material was modelled using density functional theory (DFT), which identified interstitial positions as the preferential location of the dopant. DFT models were also used to shed light on the influence of boron on surface segregation, surface stability, and oxygen binding energy in NCM85 …

Kerr-lens mode-locking (KLM) is the work-horse mechanism for generation of ultrashort pulses, where a non-linear lens forms an effective ultrafast saturable absorber within the laser cavity. According to standard theory, the pulse in the cavity is a soliton, with a temporal profile and power determined by the non-linearity to exactly counteract diffraction and dispersion, resulting in pulses, whose power and shape are fixed across a wide range of pump powers. We show numerically and demonstrate experimentally that the non-local effect of the Kerr lens in a linear cavity allows the laser to deviate from the soliton model by breaking the spatial symmetry in the cavity between the forward and backward halves of the round-trip, and hence to extract more power in a single pulse, while maintaining stable cavity propagation. We confirm this prediction experimentally in a mode-locked Ti:Sapphire laser with a quantitative agreement to the simulation results. Our numerical tool opens new avenues to optimization and enhancement of the mode-locking performance based on direct examination of the Kerr medium and the spatio-temporal dynamics within it, which is difficult (or even impossible) to observe experimentally.

Sunlight-driven photocatalysis is an environmentally friendly approach to solve ecological issues. The development of simple yet sufficiently stable photocatalytic materials capable of responding to the full-spectrum light remains challenging. Here, we demonstrate the phase transformations of bulk copper sulfides from digenite (Cu9S5) to djurleite (Cu1.97S) and low chalcocite (Cu2S) by the reactive thermal annealing during ambient pressure chemical vapor deposition, followed by their top-down exfoliation. Using multiple techniques, we confirm that monoclinic Cu2S is primarily formed at higher temperatures or greater reaction times and using a reducing atmosphere. We measured the average thickness to be approximately 4 nm for the exfoliated flakes with relatively large lateral sizes of up to 10 μm. We tested the three phases of bulk copper sulfides and their exfoliated forms as photocatalysts for dye degradation …

We explore experimentally synchronization and persistent beating dynamics in coupled non-degenerate parametric oscillators. We demonstrate that synchronization is completely prevented due to mode competition, which is unique to non-degenerate oscillators.

Recently proposed direct-detection laser range finders transmit low power, periodic, unipolar (ON-OFF) coded signal, instead of the commonly used strong narrow single pulse. The combination of non-coherent pulse compression (NCPC) and appropriate binary sequences produces a sidelobe-free periodic delay response. The continuous wave (CW) nature of the signal results in overlaps between returns from multiple targets. When envelope detected, the overlaps can create intermodulation that may hurt the sidelobe-free range response. The paper studies the effect of different sequence types and different envelope detector response profiles and suggests measures to mitigate the influence of multiple targets by calibration of envelope detector.

The visibility of nonlinear SU(1,1) interference directly reflects the nonclassical properties of entangled bi-photons and squeezed light with practically unlimited bandwidth, high efficiency and ultra-high photon flux, orders of magnitude beyond the abilities of standard photo-detectors. We study experimentally the dependence of the SU(1,1) visibility on the phase matching conditions and beam parameters in a free-space configuration, and show that maximal SU(1,1) visibility requires extreme collinear conditions, which deviate from the conditions for maximal nonlinear conversion. We demonstrate near-ideal visibility of ~95% (limited only by internal loss) in an ultra-broadband SU(1,1), interferometer with over 120THz of squeezed light bandwidth. Utilizing this analysis we demonstrate efficient detection of the spectral phase of single-cycle bi-photons and precise compensation of the dispersion over a full octave of …