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Abstract Interfacial magnetic interactions between different elements are the origin of various spin-transport phenomena in multi-elemental magnetic systems. We investigate the coupling between the magnetic moments of the rare-earth, transition-metal, and heavy-metal elements across the interface in a GdFeCo/Pt thin film, an archetype system to investigate ferrimagnetic spintronics. The Pt magnetic moments induced by the antiferromagnetically aligned FeCo and Gd moments are measured using element-resolved x-ray measurements. It is revealed that the proximity-induced Pt magnetic moments are always aligned parallel to the FeCo magnetic moments, even below the ferrimagnetic compensation temperature where FeCo has a smaller moment than Gd. This is understood by a theoretical model showing distinct effects of the rare-earth Gd 4f and transition-metal FeCo 3d magnetic moments on the Pt electronic states. In particular, the Gd and FeCo work in-phase to align the Pt moment in the same direction, despite their antiferromagnetic configuration. The unexpected additive roles of the two antiferromagnetically coupled elements exemplify the importance of detailed interactions among the constituent elements in understanding magnetic and spintronic properties of thin film systems.

Abstract We investigate the voltage control of magnetism in a van der Waals (vdW) heterostructure device consisting of two distinct vdW materials, the ferromagnetic Fe3-x GeTe2 and the ferroelectric In2Se3. It is observed that gate voltages applied to the Fe3-x GeTe2/In2Se3 heterostructure device modulate the magnetic properties of Fe3-x GeTe2 with significant decrease in coercive field for both positive and negative voltages. Raman spectroscopy on the heterostructure device shows voltage-dependent increase in the in-plane In2Se3 and Fe3-x GeTe2 lattice constants for both voltage polarities. Thus, the voltage-dependent decrease in the Fe3-x GeTe2 coercive field, regardless of the gate voltage polarity, can be attributed to the presence of in-plane tensile strain. This is supported by density functional theory calculations showing tensile-strain-induced reduction of the magnetocrystalline anisotropy, which in turn decreases the coercive field. Our results demonstrate an effective method to realize low-power voltage-controlled vdW spintronic devices utilizing the magnetoelectric effect in vdW ferromagnetic/ferroelectric heterostructures.

Abstract The interplay between ferromagnetism and the non-trivial topology has unveiled intriguing phases in the transport of charges and spins. For example, it is consistently observed the so-called topological Hall effect (THE) featuring a hump structure in the curve of the Hall resistance (R xy ) vs. a magnetic field (H) of a heterostructure consisting of a ferromagnet (FM) and a topological insulator (TI). The origin of the hump structure is still controversial between the topological Hall effect model and the multi-component anomalous Hall effect (AHE) model. In this work, we have investigated a heterostructure consisting of BixSb2−xTeySe3−y (BSTS) and Cr2Te3 (CT), which are well-known TI and two-dimensional FM, respectively. By using the so-called “minor-loop measurement”, we have found that the hump structure observed in the CT/BSTS is more likely to originate from two AHE channels. Moreover, by analyzing the scaling behavior of each amplitude of two AHE with the longitudinal resistivities of CT and BSTS, we have found that one AHE is attributed to the extrinsic contribution of CT while the other is due to the intrinsic contribution of BSTS. It implies that the proximity-induced ferromagnetic layer inside BSTS serves as a source of the intrinsic AHE, resulting in the hump structure explained by the two AHE model. Graphical abstract

Abstract Transition metal dichalcogenides have attracted renewed interest for use as thermoelectric materials owing to their tunable bandgap, moderate Seebeck coefficient, and low thermal conductivity. However, their thermoelectric parameters such as Seebeck coefficient, electrical conductivity, and thermal conductivity are interdependent, which is a drawback. Therefore, it is necessary to find a way to adjust one of these parameters without affecting the other parameters. In this study, we investigated the effect of helium ion irradiation on MoSe2 thin films with the objective of controlling the Seebeck coefficient and electrical conductivity. At the optimal irradiation dose of 1015 cm−2, we observed multiple enhancements of the power factor resulting from an increase in the electrical conductivity, with slight suppression of the Seebeck coefficient. Raman spectroscopy, X-ray diffraction, and transmission electron microscopy analyses revealed that irradiation-induced selenium vacancies played an important role in changing the thermoelectric properties of MoSe2 thin films. These results suggest that helium ion irradiation is a promising method to significantly improve the thermoelectric properties of two-dimensional transition metal dichalcogenides. Graphical Abstract Effect of He+ irradiation on thermoelectric properties of MoSe2 thin films.

Abstract We report on a thickness-dependent wetting property of WS2/Al2O3 and WS2/SiO2/Si structures. We prepared WS2 films with gradient thickness by annealing thickness-controlled WO3 films at 800 °C in sulfur atmosphere. Raman spectroscopy measurements showed step-like variation in the thickness of WS2 over substrates several centimeters in dimension. On fresh surfaces, we observed a significant change in the water contact angle depending on film thickness and substrate. Transmission electron microscopy analysis showed that differences in the surface roughness of WS2 films can account for the contrasting wetting properties between WS2/Al2O3 and WS2/SiO2/Si. The thickness dependence of water contact angle persisted for longer than 2 weeks, which demonstrates the stability of these wetting properties when exposed to air contamination.

Ship heave effects in the swell-prevalent Southern Ocean induce frequent false overturns in density profiles, and conventional Thorpe scale analysis leads to unrealistically large diapycnal diffusivities. Another critical factor causing large positive biases in Thorpe scale analysis concerns the Ozmidov to Thorpe scales ratio a often considered constant and equal to 0.8. A revised Thorpe scale analysis is proposed with an innovative segment-by-segment approach to circumvent heaveinduced false overturns together with best-fitting a functions to Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) data, which yields realistic diffusivities in the Drake Passage region. The revised Thorpe scale method applied to a finely-resolved CTD section across the Drake Passage yields typical diffusivities of O (10-5-10-3 m2 s-1), with the largest values being preferentially concentrated close to the bottom at major circumpolar fronts, consistent with nearby DIMES microstructure observations. In the southern Drake Passage the method highlights a middepth (500-1500 m) mixing maximum of 10-4-10-3 m2 s-1 in the Lower Circumpolar Deep Water (LCDW) layer due to large intrusions of Warm Deep Water (a cold/fresh variety of LCDW) of Weddell Gyre origin. The inferred middepth mixing maximum in intrusive regions, which is associated with isopycnal eddy stirring rather than caused by internal waves or double diffusive mixing, supports the short-circuiting paradigm of meridional overturning circulation in the southwestern Scotia Sea region and has important climatic implications in a warming climate. [ABSTRACT FROM AUTHOR]

Background/Aims: Sedation has become a standard practice for patients undergoing gastrointestinal (GI) endoscopy. However, considering the serious cardiopulmonary adverse events associated with sedatives, it is important to identify patients at high risk. Machine learning can generate reasonable prediction for a wide range of medical conditions. This study aimed to evaluate the risk factors associated with sedation during GI endoscopy and develop a predictive model for hypoxia during endoscopy under sedation. Methods: This prospective observational study enrolled 446 patients who underwent sedative endoscopy at the Korea University Ansan Hospital. Clinical data were used as predictor variables to construct predictive models using the random forest method that is a machine learning algorithm. Results: Seventy-two of the 446 patients (16.1%) experienced life-threatening hypoxia requiring immediate medical intervention. Patients who developed hypoxia had higher body weight, body mass index (BMI), neck circumference, and Mallampati scores. Propofol alone and higher initial and total dose of propofol were significantly associated with hypoxia during sedative endoscopy. Among these variables, high BMI, neck circumference, and Mallampati score were independent risk factors for hypoxia. The area under the receiver operating characteristic curve for the random forest-based predictive model for hypoxia during sedative endoscopy was 0.82 (95% confidence interval, 0.79-0.86) and displayed a moderate discriminatory power. Conclusions: High BMI, neck circumference, and Mallampati score were independently associated with hypoxia during sedative endoscopy. We constructed a model with acceptable performance for predicting hypoxia during sedative endoscopy. [ABSTRACT FROM AUTHOR]

Background: The medial canthal region features a complex three-dimensional and internal anatomical structure. When reconstructing a defect in this area, it is crucial to consider both functional and aesthetic aspects, which presents significant challenges. Generally, local flaps are preferred for reconstruction; however, skin grafts can be used when local flaps are not feasible. Therefore, we conducted a comparative analysis of surgical outcomes skin grafts when local flaps were not feasible, to determine which surgical method is more effective for medial canthal region reconstruction. Methods: Twenty-five patients who underwent medial canthal region reconstruction using skin grafts or local flaps from 2002 to 2021 were enrolled. Patient information was obtained from medical records. Five plastic surgeons evaluated the surgical outcomes based on general appearance, color, contour, and symmetry. Results: Skin grafts were used in eight patients and local flaps were used in 13. Combined reconstructions were employed in four cases. Minor complications arose in four cases but improved with conservative treatment. No major complications were reported. Recurrence of the skin cancer was noted in two cases. All categories showed higher scores for the local flap compared to both skin graft and combined reconstruction; however, the differences were not statistically significant respectively. Conclusion: The choice of appropriate surgical methods for reconstructing defects in the medial canthal region depends on various factors, including the patient's overall health, the size and depth of the defect, and the degree of involvement of surrounding structures. When a local flap is not feasible, a skin graft may provide favorable surgical outcomes. Therefore, a skin graft can serve as a viable alternative for reconstructing the medial canthal region. [ABSTRACT FROM AUTHOR]

An air-sea interaction field campaign was conducted in September of 2017 within the warm and cold eddy region of the western Northwest Pacific (WNP) (17.5°-20.5°N, 127.5°E-133.5°E). Both near-surface oceanic and atmospheric conditions in addition to ocean heat content (OHC) were examined to better understand the mechanisms governing high heat flux magnitudes responsible for rapidly intensifying tropical cyclones. Observations from this experiment indicate that the latent heat flux (LHF) under modest wind conditions reached 400Wm-2 within the vicinity of a warm eddy, with OHC higher than 100 kJ cm-2 of warm eddy region being 2~3 times as large as that of cold eddy region. These high OHC and a resultant high LHF in the warm eddy, comparable to the magnitude of LHF in the North Equatorial Current, may explain the mechanism of why tropical cyclones over a warm eddy in eddy-rich zones often rapidly intensify in the WNP. A month later typhoon Lan rapidly intensified into a super typhoon, while passing over the boundary region of warm and cold eddies during the observation period. Results from this study illustrate that both the wind-normalized LHF and the difference (Qs-Qa) between the specific humidity at air (Qa) and at the sea surface (Qs), closely correlate with OHC patterns, which suggests that the ocean looks likely to control the spatial pattern of LHF. Overall, both the ocean and weather conditions govern the pattern of specific humidity difference between the air-sea interface, with large OHC over the warm eddy controlling higher Qs and the pattern of Qa depending on the pattern of wind direction. Qa as a factor impacting LHF magnitude is strongly linked to wind direction in the experimental area, that is, the drier northwesterly flow and southeasterly moist wind, resulting in the enhanced contrast of specific humidity at cold eddy region. [ABSTRACT FROM AUTHOR]