The nucleation and growth of lithium sulfides are directly observed by liquid in situ transmission electron microscopy.

Finding suitable electrode materials is one of the challenges for the commercialization of a sodium ion battery due to its pulverization accompanied by high volume expansion upon sodiation. Here, copper sulfide is suggested as a superior electrode material with high capacity, high rate, and long‐term cyclability owing to its unique conversion reaction mechanism that is pulverization‐tolerant and thus induces the capacity recovery. Such a desirable consequence comes from the combined effect among formation of stable grain boundaries, semi‐coherent boundaries, and solid‐electrolyte interphase layers. The characteristics enable high cyclic stability of a copper sulfide electrode without any need of size and morphological optimization. This work provides a key finding on high‐performance conversion reaction based electrode materials for sodium ion batteries.

Coacervation is considered as a ubiquitous mechanism for assembling biomolecular materials outside cells and organizing membraneless organelles inside cells. Despite the importance of mapping binodals to understand the driving forces and thermodynamics of coacervate, quantifying protein concentration within a droplet is significantly challenging owing to its dynamic and viscous nature. A direct imaging‐based method is presented to quantify coacervate using real‐time 3D quantitative phase imaging. The proposed method utilizes the measurements of the refractive index tomograms of individual coacervates and retrieves the protein concentration and volume of individual protein droplets exploiting light‐scattering analysis. The retrievals of accurate protein concentrations are demonstrated in droplets, whereas conventional fluorescence‐based techniques present underestimations. With its simple, direct, real‐time, and quantitative analysis capability, the present method can be utilized in various protein analyses and quantifications for the study of coacervation both in vitro and in vivo.

Binary metal sulfides have been explored as sodium storage materials owing to their high theoretical capacity and high stable cyclability. Nevertheless, their relative high charge voltage and relatively low practical capacity make them less attractive as an anode material. To resolve the problem, addition of alloying elements is considerable. Copper antimony sulfide is investigated as a representative case. In this study, we do not only perform electrochemical characterization on CuSbS 2 , but also investigate its nonequilibrium sodiation pathway employing in-/ex situ transmission electron microscopy, in situ X-ray diffraction, and density functional theory calculations. Our finding provides valuable insights on sodium storage into ternary metal sulfide including an alloying element.

Photonic integrated circuits and mid-infrared quantum cascade lasers have attracted significant attention over the years because of the numerous applications enabled by these compact semiconductor chips. In this paper, we demonstrate low loss passive waveguides and highly efficient arrayed waveguide gratings that can be used, for example, to beam combine infrared (IR) laser arrays. The waveguide structure used consists of an In0.53Ga0.47As core and InP cladding layers. This material system was chosen because of its compatibility with future monolithic integration with quantum cascade lasers. Different photonic circuits were fabricated using standard semiconductor processes, and experiments conducted with these chips demonstrated low-loss waveguides with an estimated propagation loss of ∼ 1.2 dB/cm as well as micro-ring resonators with an intrinsic Q-factor of 174,000. Arrayed waveguide gratings operating in the 5.15–5.34 µm range feature low insertion loss and non-uniformity of ∼ 0.9 dB and ∼ 0.6 dB, respectively. The demonstration of the present photonic circuits paves the path toward monolithic fabrication of compact infrared light sources with advanced functionalities beneficial to many chemical sensing and high-power applications.

The current prevailing methods for identifying immune cell subsets exploit a group of differentiation markers (CDs) targeted by fluorochrome or metal conjugated antibodies. However, such labeling methods, requiring a staining process and specific reagents, prevent rapid and cost-effective identification of immune cell subsets. Therefore we developed a label-free imaging cytometry platform that synergistically used refractive index (RI) tomography and three-dimensional (3-D) deep learning. We constructed and trained a deep learning classifier that learns unique representations from the 3-D RI map of each cell obtained using RI tomography without labeling. In this study, we were able to classify human naïve, memory, and senescent T cells according to the expression of CD4, CD8, CD45RA, CCR7 and CD57 using the label-free classifier within milliseconds, with high precision (>95%) even though the morphological and biochemical characteristics extracted from the RI tomograms of the T cells are almost homogeneous. This cannot be achieved by conventional machine learning approaches that only exploit the set of manually extracted features. Our label-free cell sorting platform will facilitate rapid and cost-effective immunological and biomedical studies by eliminating the laborious labeling process.

We report the fabrication of InGaAs/InP based arrayed waveguide gratings featuring low insertion loss and non-uniformity. This device can be integrated monolithically with on-chip III-V lasers to make compact high-power mid-infrared sources.

In article number 1900264 , Jong Min Yuk and co‐workers visualize four types of semi‐coherent boundaries formed during sodiation in copper sulfide utilizing high‐resolution transmission electron microscopy. The semi‐coherent boundaries do not only act as mechanical pillars for pulverization‐tolerance, but also provide additional sodium transport paths for capacity recovery. The novel sodiation mechanism enables exceptionally stable sodium storage in copper sulfide.