22 research outputs found

    Investigation of the mechanism of the anomalous Hall effects in Cr2Te3/(BiSb)2(TeSe)3 heterostructure

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    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 (Rxy) 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

    Investigation of the mechanism of the anomalous Hall effects in Cr2Te3/(BiSb)2(TeSe)3 heterostructure

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    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 (Rxy) 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.This work was supported by the Korea Institute of Science and Technol‑ogy (KIST) through 2E31550 and by the National Research Foundation program through NRF-2021M3F3A2A03017782, 2021M3F3A2A01037814, 2021M3F3A2A01037738, 2021R1A2C3011450, and 2020R1A2C200373211,[Innovative Talent Education Program for Smart City] by MOLI

    All inorganic electrochemical transistor with correlated oxides for low power and thermally stable arti cial synapses

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    Synapse, a combination of memory and information processing units, is the ultimate goal to emulate for electronic devices. They outperform a conventional von-Neumann architecture in terms of information processing speed and energy eciency. Recent studies mimicked synaptic functions and minimized energy per synaptic event by using a phase change memory (100 fJ for 100 nm2 device area)1 and an organic electrochemical transistor (10 pJ for 1000 m2 device area)2, but the energy consumption is still greater than that of the biological synapse (10 fJ). In addition, the organic electronic devices have been showed unreliable property at high temperature which is not appropriate for practical applications. Correlated oxides exhibit high thermal stability due to the inorganic nature as well as a strong electron correlation in narrow d-band that result in extremely sensitive electrical properties to their electronic conguration. They exhibit electrical phase transition by external stimuli, so-called a metal-to-insulator transition, which are not only consuming less energy but also faster, making them suitable for use in high-speed and low-power neuromorphic devices. Recently, hydrogen is reversibly injected into SmNiO3, which gives rise to the non-volatile resistivity change of 108 orders of magnitude.3 In this study, we have demonstrated an inorganic electrochemical transistor using a NdNiO3 thin lm as a channel layer and a porous silica lm as a proton exchange membrane. As an electric eld is applied to a gate electrode, a positively charged protons migrate into or out of the NdNiO3 channel layer. As a result, the channel conductance switches due to a change in the proton doping concentration in the NdNiO3 layer. The devices showed nonvolatile and distinct multilevel conductance switching, and synaptic functions. In addition, it has achieved low gate pulse amplitude (50 mV), energy eciency (1.8 pJ for 4000 m2 device area), and thermally stable operation up to 200 oC. It will guide the development of thermally stable neuromorphic device that can catch up with the energy eciency of biological synapses.1

    A population-based cohort study of longitudinal change of high-density lipoprotein cholesterol impact on gastrointestinal cancer risk

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    High-density Lipoprotein Cholesterol (HDL-C) levels have been associated with cancer. In this observational population-based cohort study using data from the Korean National Health Insurance Service system, we investigate the impact of longitudinal changes in HDL-C levels on gastrointestinal cancer risk. Individuals who underwent health examinations in 2010 and 2014 were followed-up through 2021. Among 3.131 million, 40696 gastric, 35707 colorectal, 21309 liver, 11532 pancreatic, 4225 gallbladder, and 7051 biliary cancers are newly detected. The persistent low HDL-C group increases the risk of gastric, liver, and biliary cancer comparing to persistent normal HDL-C group. HDL-C change from normal to low level increases the risk for gastric, colorectal, liver, pancreatic, gallbladder, and biliary cancers. Effects of HDL-C change on the gastrointestinal cancer risk are also modified by sex and smoking status. HDL-C changes affect the gastric and gallbladder cancer risk in age ≥60 years and the pancreatic and biliary cancer risk in age <60 years. Here, we show persistently low HDL-C and normal-to-low HDL-C change increase gastrointestinal cancer risk with discrepancies by sex, smoking status, and age

    Effects of maternal influenza vaccination on adverse birth outcomes: A systematic review and Bayesian meta-analysis.

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    BackgroundAlthough pregnant women are a priority group for influenza vaccination, its effect on birth outcomes has long been debated. Numerous observational studies and a few randomized controlled studies have been conducted, with inconsistent results.ObjectivesTo evaluate the association of influenza vaccination in pregnancy with adverse birth outcomes.Data sourceThe Cochrane Library, PubMed, EMBASE, Web of Science, and Scopus were searched.Study eligibility criteriaThis analysis included randomized placebo-controlled studies, cohort studies, and case-control studies, in which inactivated influenza vaccination was given during pregnancy and fetal adverse birth outcomes were assessed.Participants & interventionWomen who received inactivated influenza vaccine during pregnancy and their offspring.Study appraisal and synthesisTwo independent reviewers and a third reviewer collaborated in study selection and data extraction. A Bayesian 3-level random-effects model was utilized to assess the impact of maternal influenza vaccination on birth outcomes, which were presented as odds ratios (ORs) with 95% credible interval (CrIs). Bayesian outcome probabilities (P) of an ORResultsAmong the 6,249 identified publications, 48 studies were eligible for the meta-analysis, including 2 randomized controlled trials, 41 cohort studies, and 5 case-control studies. The risk of none of the following adverse birth outcomes decreased significantly: preterm birth (OR = 0.945, 95% CrI: 0.736-1.345, P = 73.3%), low birth weight (OR = 0.928, 95% CrI: 0.432-2.112, P = 76.7%), small for gestational age (OR = 0.971, 95% CrI: 0.249-4.217,P = 63.3%), congenital malformation (OR = 1.026, 95% CrI: 0.687-1.600, P = 38.0%), and fetal death (OR = 0.942, 95% CrI: 0.560-1.954, P = 61.6%). Summary estimates including only cohort studies showed significantly decreased risks for preterm birth, small for gestational age and fetal death. However, after adjusting for season at the time of vaccination and countries' income level, only fetal death remained significant.ConclusionThis Bayesian meta-analysis did not find a protective effect of maternal influenza vaccination against adverse birth outcomes, as reported in previous studies. In fact, our results showed evidence of null associations between maternal influenza vaccination and adverse birth outcomes

    Favorable Effect of High-Density Lipoprotein Cholesterol on Gastric Cancer Mortality by Sex and Treatment Modality

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    Studies on the effects of high-density lipoprotein cholesterol (HDL-C) on gastric cancer mortality are few, and the results are inconsistent. In this study, we investigated the effects of HDL-C on gastric cancer mortality and conducted sub-group analysis by sex and treatment modality. Newly diagnosed patients with gastric cancer (n = 22,468) who underwent gastric cancer screening between January 2011 and December 2013 were included and followed up until 2018. A validation cohort (n = 3379) that had newly diagnosed gastric cancer from 2005 to 2013 at a university hospital, was followed up until 2017. HDL-C was inversely related with mortality; adjusted hazard ratio (aHR) 0.90 (95% confidence interval [CI], 0.83–0.98) for HDL-C of 40–49 mg/dL, 0.86 (0.79–0.93) for HDL-C of 50–59 mg/dL, 0.82 (0.74–0.90) for HDL-C of 60–69 mg/dL, and 0.78 (0.69–0.87) for HDL-C ≥ 70 mg/dL compared to HDL-C p for trend < 0.001) as more remarkable in endoscopic resection group. In this study, we explored that an increased HDL-C reduced mortality in both sexes and curative resection group
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