JEOL (Japan)

We demonstrate a multi-beam scanning transmission electron microscopy (STEM) imaging that integrates down-sampling with super-resolution image reconstruction via a compressive sensing framework. A custom condenser aperture with six randomly positioned circular holes is employed to produce a multi-beam STEM probe, with the beam shape and distribution tuned through defocus. While the raw multi-beam images exhibit overlapping patterns, reconstruction using Adam optimization and total variation normalization yields high-fidelity images that closely reproduce the original sample structures, even from substantially down-sampled data. The proposed approach offers a pathway toward significant acceleration of such techniques through multibeam sparse sampling and computational reconstruction potentially useful for the analytical scanning methods in general.

Membrane-bound alcohol dehydrogenase (ADH) from Gluconobacter oxydans is a direct electron transfer-type biocatalyst for ethanol oxidation. To improve its bioelectrocatalysis, the membrane-binding regions of ADH were predicted and then deleted. A soluble ADH variant without surfactants was purified from the soluble fraction and characterized using structural and bioelectrochemical approaches.

Abstract Mg3Bi2-based materials exhibit high thermoelectric performance, but their poor atmospheric stability hinders practical applications. In this study, we enhanced the stability of Mg3Bi2 thin films by applying an amorphous Si capping layer. The capped films effectively suppressed decomposition of Mg3Bi2 into Bi upon atmospheric exposure, resulting in a stable and higher thermoelectric power factor of over 3.0 μW cm−1 K−2 at room temperature compared to uncapped films. Our results demonstrate that an amorphous Si capping layer not only provides essential atmospheric stability to Mg3Bi2 but also preserves its inherent high thermoelectric properties, advancing its viability for practical applications.

We developed a split-type radio frequency (RF) coil using a high-temperature superconductor (HTS) for nuclear magnetic resonance (NMR). The coil does not have HTS thin film on substrates in the area closest to the cylindrical sample. Thus, the coil suppressed the distortion of the static magnetic field. The decreasing quality factor of the coil when a sample was loaded was suppressed because the electric-field-concentration area was placed far from the sample. The measured quality factor of the coil cooled to 11 K was 20 times higher than that of the cooled copper RF coil when D<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O was loaded. The measured maximum distortion of the static magnetic field when the split-type HTS coil was implemented was suppressed to about 37% of that when the conventional HTS coil was implemented.

Abstract Transmission electron microscopy (TEM) has long been constricted by the need to place samples within high-magnetic fields during imaging, limiting direct atomic-resolution examination of magnetic materials. The JEOL MARS (Magnetic field-free Atomic Resolution imaging System, JEM-Z200MF) represents a revolution in TEM by enabling atomic-resolution imaging in a magnetic field-free environment. By incorporating a new objective lens system that realizes a magnetic field-free environment at the sample position, the MARS enables direct and atomic-level observation of samples without unwanted high-magnetic field effects.

Abstract. This study investigated the crystalline textural properties of an Antarctic deep ice core with a length of 3035 m acquired from an inland plateau dome, with a focus on depths below 2400 m. The cluster strength of the c axes was ascertained using the dielectric tensor method to assess the bulk properties of thick sections, and detailed orientation distributions of the c and a axes were determined using the Laue X-ray diffraction technique. The c- and a-axis fabric data were compared with various other characteristics of the same ice core. Microstructural observations were made using optical microscopy. The clustering strength of the single-pole c-axis fabric was at a maximum at depths between 2400 and 2640 m. The relationship between the cluster strength and the concentration of dusty impurities was found to change at approximately 2640 m, and fluctuations in strength increased significantly below this depth. Impurity-rich layers maintained a high degree of clustering, whereas layers with fewer impurities showed relaxation. The latter layers also exhibited evidence of nucleation and grain boundary migration. In ice such as this, the degree of a-axis organization was increased with one or two sets of three preferred orientations. Dynamic recrystallization evidently played a critical role, with more pronounced effects in impurity-poor layers than in impurity-rich layers. This phenomenon promoted the relaxation of the c-axis clustering, deformation based on dislocation creep and organization of the a axis. Below 2580 m, the angles of inclination of the c-axis cluster and layers deviated significantly from the vertical, suggesting that the system rotated as a rigid body as a result of simple shear.

Abstract A synergetic strategy on lattice and surface is implemented using a NaTi 2 (PO 4 ) 3 (NTP) ionic conductor for the P3‐type Na 0.67 [Zn 0.3 Mn 0.7 ]O 2 (NZMO) cathode material; specifically, the stabilization of the oxide lattice through Ti incorporation and the reinforcement of the surface stability with P‐containing moieties. This dual functionality enhances electrode performances in terms of long‐term capacity retention and charge transfer. More importantly, the presence of the NTP layer contributes to the interfacial stability under high voltage conditions, which is associated with lattice oxygen redox occurring in the highly oxidized Na x [Zn 0.3 Mn 0.7 ]O 2 O/P phase, triggered by Zn migration from the transition metal layer to the Na layer. The enhanced electrode performance is likely attributed to enhanced surface stability, increased ionic conductivity, and the stabilization of the anionic O 2− /(O 2 ) n− redox progress at high voltage. The NTP layer suppresses surface reactions with the electrolyte by scavenging HF and H 2 O, while the introduced Ti contributes to the stabilization of the c ‐axis variations. Additionally, ab initio molecular dynamics simulations suggest that the NTP layer acts as a protective barrier against electrolyte degradation, preventing HF‐induced metal ion dissolution and ensuring long‐term stability. These results demonstrate the effectiveness of NTP coatings in enhancing the performance of cathode materials for sodium‐ion batteries.

Mycoplasma pneumoniae and Mycoplasma genitalium are bacterial wall-less human pathogens and the causative agents of respiratory and reproductive tract infections. Infectivity, gliding motility and adhesion of these mycoplasmas to host cells are mediated by orthologous adhesin proteins forming a transmembrane adhesion complex that binds to sialylated oligosaccharides human cell ligands. Here we report the cryo-EM structure of M. pneumoniae P1 adhesin bound to the Fab fragment of monoclonal antibody P1/MCA4, which stops gliding and induces detachment of motile cells. The epitope of P1/MCA4 involves residues only from the small C-domain of P1. This epitope is accessible to antibodies only in the "closed conformation" of the adhesion complex and is not accessible in the "open" conformation, when the adhesion complex is ready for attachment to sialylated oligosaccharides. Polyclonal antibodies generated against the large N-domain of P1 or against the whole ectodomain of P40/P90 have little or no effects on adhesion or motility. Moreover, mutations in the highly conserved Engelman motifs found in the transmembrane helix of M. genitalium P110 adhesin also alter adhesion and motility. These results show that antibodies directed to the C-domain of P1 hinder the large conformational rearrangements in this domain required to alternate between the "open" and "closed" conformations of the adhesion complex. Since transition between both conformations is essential to complete the attachment/detachment cycle of the adhesion complex, interfering with the gliding of mycoplasma cells and providing a new potential target to confront M. pneumoniae and M. genitalium infections.

Polyethylene terephthalate (PET) is widely used across various industries owing to its versatility and favorable properties, including application in beverage bottles, food containers, textile fibers, engineering resins, films, and sheets. However, polymer materials are susceptible to degradation from factors such as light, oxygen, and heat. Therefore, it is crucial to understand the structural changes that occur during degradation and the extent of these changes. This report investigates the structural alterations in PET films resulting from ultraviolet (UV) irradiation utilizing pyrolysis–gas chromatography time-of-flight mass spectrometry (Py-GC-TOFMS) and matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOFMS). Using the reactive Py-GC-TOFMS, we estimated the composition of the pyrolysis products resulting from UV degradation through electron ionization, soft ionization, and exact mass measurements. Additionally, artificial intelligence (AI)-based structure analysis was performed to evaluate these compounds’ structures. Notably, most degradation products were not found in the National Institute of Standards and Technology database, underscoring the effectiveness of our approach. Using MALDI-TOFMS analysis, we determine the changes in the end groups before and after UV irradiation. This analysis confirmed the generation of a series of carboxylic acid end groups as a result of degradation, a polymer series not detected by reactive pyrolysis GC-MS. We also explored degradation in the depth direction, demonstrating that degradation progresses gradually to depths of several micrometers. Our findings highlight the importance of employing mass spectrometry techniques for a comprehensive analysis of polymer degradation.