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Magnetic van der Waals (vdW) materials offer an opportunity to design heterostructures that will lead to exotic functionalities that arise from interfacial interaction. In addition to coupling to different vdW materials, the naturally oxidized surface layer of a vdW material also forms a heterostructure with its bulk film, giving rise to intriguing phenomena. Here, we directly observe the impact of oxidation on the magnetic domains, namely, magnetic stripe domain and skyrmions, in a nanoscale Fe3GeTe2 flake using cryo Lorentz transmission electron microscopy. After the Fe3GeTe2 is exposed to ambient conditions, partial oxidation leads to an increase in the density of skyrmions even under zero magnetic field. Complete oxidation leads to a loss of the magnetic domain structure. We observe a gradual change in Fe3GeTe2 from single crystal to amorphous as the oxidation increases. The oxidized Fe3GeTe2 primarily consists of iron oxide, which could be antiferromagnetic in nature. We hypothesize that the interfacial interaction between these surface antiferromagnetic oxides and the bulk ferromagnetic Fe3GeTe2, as well as the effect of interfacial roughness, leads to the increase in Néel skyrmion creation. This work opens a path to harness controlled oxidation as a build block to create dense skyrmion lattices without the need for an external magnetic field, leading to potential future applications in spintronic devices. [ABSTRACT FROM AUTHOR]

Myelitis, including longitudinally extensive transverse myelitis (LTEM), is reported in more than forty patients after coronavirus disease 2019 (COVID-19). Among COVID-19 vaccines, only Oxford-AstraZeneca COVID-19 vaccine (AZD1222) has been associated with few cases of myelitis (1 LTEM). We report the first case of myelitis/LTEM after BBIBP-CorV/Sinopharm vaccine, interestingly presented as a hemicord syndrome. A 71-year-old male presented with left-side diplegia, right-side hemihyposthesis with facial sparing and impaired position sensation in left foot after vaccination with BBIBP-CorV. MRI revealed a longitudinal signal in left cervical hemicord. This is the first reported myelitis and LTEM with COVID-19 vaccines other than AZD1222.

Summary: Liquid phase transmission electron microscopy allows the imaging of materials in liquid environments. The sample is encapsulated within electron‐beam transparent windows and hence protected by the ultrahigh vacuum necessary within the electron gun. Such an approach allows to study biological and soft materials in their natural environment and offers the possibility of accessing their dynamic nature. Yet, the electron beam scattering from the windows and solvent increases the image noise and blur. Herein, we propose a pipeline to both de‐noise and sharpen images obtained by liquid transmission electron microscopy. We develop the workflow in a way that it does not require any human interference, nor introduce artefacts, but actually unveils features of the imaged samples covered by the noise and the blur. Lay Description: Transmission Electron Microscopy TEM is one of the most powerful techniques for structural determination at the nanoscale, with the ability to image matter down to the atomic level. TEM is only possible by keeping the electron beam under high vacuum in order to avoid undesired scattering events in the beam path. High vacuum means that the TEM samples must conventionally be in solid‐state. Thus, samples in liquid form or containing liquids, like water, need special preparation techniques which tend to alter the structure and chemical nature of the sample. Such alterations are particularly critical for biological and soft organic materials where the structures are controlled by the presence of water and/or other liquids. The development of new cameras, materials and sample holders have made possible for TEM to be performed on liquid samples. Liquid Phase Transmission Electron Microscopy (LTEM) offers the possibility to investigate nanoscopic structures in liquid state and monitor dynamic processes. However important limitations come from the liquid nature of samples in the imaging process such as the low contrast afforded by organic and biological materials and additional noise and blur introduced by the liquid sample and its thickness. Existing image analysis algorithms for TEM result inadequate for LTEM. The end‐to‐end image analysis method herein has the ability to recover the original images together with their sharpness, without introducing any artefacts. The proposed algorithms offer the great advantage of unveiling image details which are not usually seen during imaging, thus allowing a better understanding of the nature, structure and ultimately the function of the investigated structures. The fully automatised analysis method allows to efficiently process dozens of images in few hours, improving dramatically the performance of LTEM imaging [ABSTRACT FROM AUTHOR]

Abdominal CT scans have been widely studied and researched by medical professionals in recent years. CT scans have proved effective for the task of detection of liver abnormalities in patients. Computer-aided automatic segmentation of the liver can serve as an elementary step for radiologists to trace anomalies in the liver. In this paper, we have explored deep learning techniques first and foremost for the extraction of liver from the abdominal CT scan and then, consequently, to segment the lesions from a tumour-ridden liver. A cascaded model of convolutional neural networks is used to segment lesions once tumour has been detected in the liver by GA-ANN which has been fed textural liver features using LTEM for its classification procedure. A high DICE index has been obtained of 0.9557 for liver segmentation and 0.6976 for lesion segmentation. [ABSTRACT FROM AUTHOR]

• Magnetic skyrmion and successive domain evolution in NdCo 5 alloys were directly observed by LTEM. • Spontaneous magnetic skyrmions at zero field occurs in NdCo 5 alloys. • The temperature range of spontaneous skyrmions is enhanced by rapid solidification. • The manipulation of the topological spin textures depends on the crystal orientation. Magnetic skyrmions are topologically stable magnetic textures with novel behaviors suitable for applications in future spintronic devices. Tuning the temperature range of topological spin textures is imperative for their potential applications. Here, by means of the rapid solidification, topological magnetic transitions in the NdCo 5 bulk alloy are manipulated whereby skyrmions spontaneously generate at a higher temperature in ribbons. The direct observation of magnetic domain evolution via in situ Lorentz transmission electron microscopy reveals that the topological magnetic transition is dependent on the crystal orientations, where magnetic domain evolution is different within the a-b plane between the bulk and ribbons of NdCo 5. Our work provides a way to tune the temperature range of topological spin textures and helps to clarify the importance of magnetic anisotropy on stabilizing the topological spin textures. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of TA on the magnetic properties of SMPCs was investigated. • The reasons for the improvement of magnetic properties by TA were analyzed. • The effect of TA on the magnetic domain structure was explored. • SMPCs showed high effective permeability (47.8) and low core loss (689 mW/cm3). In this work, transverse magnetic field annealing (TA) was performed to FeSiBNbCu nanocrystalline powder cores (NPCs), and the magnetic properties, microstructure, and magnetic domain structure were in detail studied comparing with those after normal annealing (NA), and the mechanism of the improvement of soft magnetic properties by TA was elucidated. The experimental results show that the core loss of the sample is reduced by 14 % and the coercivity is reduced by 38 % after TA at 450 °C compared to the NA sample. The direct current bias performance of the TA sample is maintained at 67 % under a 100 Oe bias field. TA optimizes the soft magnetic properties of NPCs by optimizing the domain structure, reducing the formation of micro-vortex dots and broadening the size of the domain. These results can provide a good guide for optimizing the performance of NPCs with low core loss at high frequency. [ABSTRACT FROM AUTHOR]

• Direct observation of the magnetic domain configuration in amorphous or nanocrystalline Tb(Co 1− x Fe x) 5 ribbons using in-situ LTEM. • High-density magnetic vortex state is obtained in the amorphous TbFe 5 ribbon. • Distinguished magnetic vortex evolution under temperature and the in-plane magnetic field is demonstrated. Nontrivial spin textures including magnetic vortices, skyrmions, and merons possess intriguing properties that are suitable for the application in further spintronics devices. The stability of topological spin textures in a broad temperature span is imperative for their potential applications as information carriers. In this study, we show the in-situ observation of the magnetic domain configuration and their manipulation under temperature and in-plane magnetic field in amorphous or nanocrystalline Tb(Co 1− x Fe x) 5 (x = 0.5, 0.8, 1.0) ribbons using Lorentz transmission electron microscopy. The results demonstrate that the formation of magnetic vortices is highly dependent on the degree of amorphization of Tb(Co 1− x Fe x) 5 ribbons and intrinsic magnetic parameters, which can be controlled by the composition. The higher the Fe content, the stronger the degree of amorphous in Tb(Co 1− x Fe x) 5 ribbons. Whereby, high-density magnetic vortices develop inside domain walls in the TbFe 5 ribbon. Moreover, no matter how the degree of amorphization changes, magnetic domain structures including vortices in these ribbons have good thermal stability in the temperature range of 120–300 K, while the evolution of magnetic domains under the application of magnetic field is greatly affected by the degree of amorphization. The cross-tie domain walls consisted of magnetic vortices and antivortices form as applying a proper magnetic field in TbFe 5 , in contrast with the unchanged magnetic domains in Tb(Co 0.5 Fe 0.5) 5. This study provides a guideline for the design of magnetic vortex materials and soft magnetic materials. [ABSTRACT FROM AUTHOR]