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Intercalation provides to the host materials a means for controlled variation of many physical/chemical properties and dominates the reactions in metal‐ion batteries. Of particular interest is the graphite intercalation compounds with intriguing staging structures, which however are still unclear, especially in their nanostructure and dynamic transition mechanism. Herein, the nature of the staging structure and evolution of the lithium (Li)‐intercalated graphite was revealed by cryogenic‐transmission electron microscopy and other methods at the nanoscale. The intercalated Li‐ions distribute unevenly, generating local stress and dislocations in the graphitic structure. Each staging compound is found macroscopically ordered but microscopically inhomogeneous, exhibiting a localized‐domains structural model. Our findings uncover the correlation between the long‐range ordered structure and short‐range domains, refresh the insights on the staging structure and transition of Li‐intercalated/deintercalated graphite, and provide effective ways to enhance the reaction kinetic in rechargeable batteries by defect engineering. The microstructure of Li+‐graphite intercalation compounds (GIC) was directly visualized by cryo‐transmission electron microscopy with minimized artifacts. Each macroscopical staging compound is a mixture of different staging phases and dislocations. It is long‐range order, medium‐range disorder, and short‐range order, which is much different from the previously proposed Rüdorff‐Hofmann and Daumas‐Hérold models. Localized‐domains model is proposed to describe the real structural nature of the Li+‐GIC.

Transmission electron microscopy in situ straining experiments of Al single crystals with different initial lattice defect densities have been performed. The as-focused ion beam (FIB)-processed pillar sample contained a high density of prismatic dislocation loops with the Burgers vector, while the post-annealed specimen had an almost defect-free microstructure. In both specimens, plastic deformation occurred with repetitive stress drops (∆σ). The stress drops were accompanied by certain dislocation motions, suggesting the dislocation avalanche phenomenon. ∆σ for the as-FIB Al pillar sample was smaller than that for the post-annealed Al sample. This can be considered to be because of the interaction of gliding dislocations with immobile prismatic dislocation loops introduced by the FIB. The reloading process after stress reduction was dominated by elastic behavior because the slope of the load–displacement curve for reloading was close to the Young’s modulus of Al. Microplasticity was observed during the load-recovery process, suggesting that microyielding and a dislocation avalanche repeatedly occurred, leading to intermittent plasticity as an elementary step of macroplastic deformation.

Scanning transmission electron microscopy (STEM) is widely used for imaging, diffraction, and spectroscopy of materials down to atomic resolution. Recent advances in detector technology and computational methods have enabled many experiments that record a full image of the STEM probe for many probe positions, either in diffraction space or real space. In this paper, we review the use of these four-dimensional STEM experiments for virtual diffraction imaging, phase, orientation and strain mapping, measurements of medium-range order, thickness and tilt of samples, and phase contrast imaging methods, including differential phase contrast, ptychography, and others.

Mg 4 Zn 7 phase, with a monoclinic unit cell, a layered structure and a unique axis showing pseudo-tenfold symmetry, grows over icosahedral quasicrystalline phase in a manner similar to a decagonal quasicrystal. In this study, the relationship of this phase to icosahedral quasicrystal is brought out by a transmission electron microscopy study of Mg 4 Zn 7 phase growing on icosahedral phase in a cast Mg-Zn-Y alloy. Lattice correspondences between the two phases have been determined by electron diffraction. Planes related to icosahedral fivefold and pseudo-twofold symmetry are identified. Possible orthogonal cells bounded by twofold symmetry-related planes have been determined. Mg 4 Zn 7 phase growing on an icosahedral phase exhibits a number of planar faults parallel to the monoclinic axis, presumably to accommodate the quasiperiodicity at the interface. Two faults were identified, which were on {200} and { 2 ¯ 01} planes. Their structures have been determined by high resolution imaging in TEM. They produce two different unit cells at the interface.

In recent years, extracellular vesicles (EVs) have become a subject of intense study. These membrane-enclosed spherical structures are secreted by almost every cell type and are engaged in the transport of cellular content (cargo) from parental to target cells. The impact of EVs transfer has been observed in many vital cellular processes including cell-to-cell communication and immune response modulation; thus, a fast and precise characterization of EVs may be relevant for both scientific and diagnostic purposes. In this review, the most popular analytical techniques used in EVs studies are presented with the emphasis on exosomes and microvesicles characterization.

The strain rate sensitivity ( m ) of (Ni 0.92 Zr 0.08 ) 100 − x Al x (0 ≤ x ≤ 4 at.%) eutectic with varying average lamellae thickness (λ w ) in the range of 39–275 nm has been investigated in the strain rate range of 8 × 10 −5 and 8 × 10 −3 s −1 at room temperature. The microstructure of the nano-/ultrafine eutectic composites (NECs) is comprised of alternate lamellae of fcc γ-Ni and Ni 5 Zr along with 20–31 vol% γ-Ni dendritic phase. The m value of all the investigated NECs lies between 0.0080 and 0.0102, whereas the activation volume ( V *) has been estimated to be between 29.7 b 3 and 49.8 b 3 . High-resolution transmission electron microscopy studies confirm the dislocation-mediated plastic flow including dislocation–lamellae interaction, and their pile-up at the interface, which result in the narrow variation of m for a wide range of λ w due to its interlocked lamellar microstructure. A mathematical model has been developed to correlate the m with λ w for the experimented NECs with wide microstructure length scale and solute content.

Corrosion is a ubiquitous failure mode of materials. Often, the progression of localized corrosion is accompanied by the evolution of porosity in materials previously reported to be either three-dimensional or two-dimensional. However, using new tools and analysis techniques, we have realized that a more localized form of corrosion, which we call 1D wormhole corrosion, has previously been miscategorized in some situations. Using electron tomography, we show multiple examples of this 1D and percolating morphology. To understand the origin of this mechanism in a Ni-Cr alloy corroded by molten salt, we combined energy-filtered four-dimensional scanning transmission electron microscopy and ab initio density functional theory calculations to develop a vacancy mapping method with nanometer-resolution, identifying a remarkably high vacancy concentration in the diffusion-induced grain boundary migration zone, up to 100 times the equilibrium value at the melting point. Deciphering the origins of 1D corrosion is an important step towards designing structural materials with enhanced corrosion resistance. Corrosion is a ubiquitous failure mode in materials. Here the authors report a percolating 1D wormhole corrosion morphology using advanced electron microscopy and theoretical simulations. The work presents a vacancy mapping method with nm-resolution, identifying the incubation sites of the wormholes.

The sperm ultrastructure and the male and female genital apparatus of Zorotypus shannoni were examined and documented in detail, mainly using transmission electron microscopy micrographs. The findings suggest an evolutionary trend shared with Z. hubbardi and Z. impolitus . The three species are characterized by enlarged mitochondrial derivatives and related modifications. Giant sperm are probably a synapomorphy of Z. hubbardi and Z. impolitus , whereas an intermediate condition of this feature is found in Z. shannoni. The monophyletic origin of Z. caudelli , Z. magnicaudelli , Z. huxleyi and Z. weidneri is suggested by characteristically modified axonemes. The presence of extra-acrosomal material is also an unusual feature for Zoraptera, but this condition also occurs in the majority of polyneopteran groups. The long and convoluted female spermathecal duct with secretory and duct-forming cells is a constant feature in Zoraptera. The enlarged seminal receptacle suggests an evolutionary link between the male genital structures and the sperm size on one hand, and the size of the female spermatheca on the other. The small and otherwise uniform group Zoraptera exhibits a remarkable variation of sperm types and genital structures, suggesting the impact of different types of selection. It is likely that cryptic female choice plays a major role in shaping the genital apparatus.

One highly diverse phylogenetic group of Bacteria, Ca . Patescibacteria, remains poorly understood, but, from the few cultured representatives and metagenomic investigations, they are thought to live symbiotically or parasitically with other bacteria or even with eukarya. Each prokaryotic domain, Bacteria and Archaea, contains a large and diverse group of organisms characterized by their ultrasmall cell size and symbiotic lifestyles (potentially commensal, mutualistic, and parasitic relationships), namely, Candidatus Patescibacteria (also known as the Candidate Phyla Radiation/CPR superphylum) and DPANN archaea, respectively. Cultivation-based approaches have revealed that Ca . Patescibacteria and DPANN symbiotically interact with bacterial and archaeal partners and hosts, respectively, but that cross-domain symbiosis and parasitism have never been observed. By amending wastewater treatment sludge samples with methanogenic archaea, we observed increased abundances of Ca . Patescibacteria ( Ca . Yanofskybacteria/UBA5738) and, using fluorescence in situ hybridization (FISH), discovered that nearly all of the Ca. Yanofskybacteria/UBA5738 cells were attached to Methanothrix (95.7 ± 2.1%) and that none of the cells were attached to other lineages, implying high host dependency and specificity. Methanothrix filaments (multicellular) with Ca. Yanofskybacteria/UBA5738 attached had significantly more cells with no or low detectable ribosomal activity (based on FISH fluorescence) and often showed deformations at the sites of attachment (based on transmission electron microscopy), suggesting that the interaction is parasitic. Metagenome-assisted metabolic reconstruction showed that Ca. Yanofskybacteria/UBA5738 lacks most of the biosynthetic pathways necessary for cell growth and universally conserves three unique gene arrays that contain multiple genes with signal peptides in the metagenome-assembled genomes of the Ca. Yanofskybacteria/UBA5738 lineage. The results shed light on a novel cross-domain symbiosis and inspire potential strategies for culturing CPR and DPANN. IMPORTANCE One highly diverse phylogenetic group of Bacteria, Ca . Patescibacteria, remains poorly understood, but, from the few cultured representatives and metagenomic investigations, they are thought to live symbiotically or parasitically with other bacteria or even with eukarya. We explored the possibility of symbiotic interactions with Archaea by amending wastewater treatment sludge samples that were rich in Ca . Patescibacteria and Archaea with an isolate archaeon that is closely related to a methanogen population abundant in situ ( Methanothrix ). This strategic cultivation successfully established enrichment cultures that were mainly comprised of Ca . Patescibacteria (family level lineage Ca . Yanofskybacteria/UBA5738) and Methanothrix , in which we found highly specific physical interactions between the two organisms. Microscopic observations based on transmission electron microscopy, target-specific fluorescence in situ hybridization, and metagenomic analyses showed evidence that the interaction is likely parasitic. The results show a novel cross-domain parasitism between Bacteria and Archaea and suggest that the amendment of host Archaea may be an effective approach in culturing novel Ca . Patescibacteria.

The recent development of electron-sensitive and pixelated detectors has attracted the use of four-dimensional scanning transmission electron microscopy (4D-STEM). Here, we present a precession electron diffraction-assisted 4D-STEM technique for automated orientation mapping using diffraction spot patterns directly captured by an in-column scintillator-based complementary metal-oxide-semiconductor (CMOS) detector. We compare the results to a conventional approach, which utilizes a fluorescent screen filmed by an external charge charge-coupled device camera. The high-dynamic range and signal-to-noise characteristics of the detector greatly improve the image quality of the diffraction patterns, especially the visibility of diffraction spots at high scattering angles. In the orientation maps reconstructed via the template matching process, the CMOS data yield a significant reduction of false indexing and higher reliability compared to the conventional approach. The angular resolution of misorientation measurement could also be improved by masking reflections close to the direct beam. This is because the orientation sensitive, weak, and small diffraction spots at high scattering angles are more significant. The results show that fine details, such as nanograins, nanotwins, and sub-grain boundaries, can be resolved with a sub-degree angular resolution which is comparable to orientation mapping using Kikuchi diffraction patterns.