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Exchange bias (EB) is a crucial property with widespread applications but particularly occurs by complex interfacial magnetic interactions after field cooling. To date, intrinsic zero-field-cooled EB (ZEB) has only emerged in a few bulk frustrated systems and their magnitudes remain small yet. Here, enabled by high temperature synthesis, we uncover a colossal ZEB field of 4.95 kOe via tuning compensated ferrimagnetism in a family of kagome metals, which is almost twice the magnitude of known materials. Atomic-scale structure, spin dynamics, and magnetic theory revealed that these compensated ferrimagnets originate from significant antiferromagnetic exchange interactions embedded in the holmium-iron ferrimagnetic matrix due to supersaturated preferential manganese doping. A random antiferromagnetic order of manganese sublattice sandwiched between ferromagnetic iron kagome bilayers accounts for such unconventional pinning. The outcome of the present study outlines disorder-induced giant bulk ZEB and coercivity in layered frustrated systems.
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The three-dimensional reconstruction technique has been widely applied across various fields, with imaging serving as a fundamental approach to achieve this reconstruction. In the present study, we employed micro-imaging to realize 3D reconstruction based on the "shape from focus" and the chromatic aberration effect. This approach eliminates the need for sample or imaging lens movement to locate the focal plane for obtaining clear images. Instead, by utilizing tunable illuminance, we can adjust the imaging distance through the chromatic aberration, thereby achieving accurate reconstructions. As a means of verification, a simple system was accordingly constructed with an adjustable illuminance range (500-750 nm) at a magnification of 10× for imaging purposes. The fine reconstruction achieved high precision in micrometers; however, the depth of field emerged as an issue during the reconstruction process. To assess this method, a coin was employed, and the resulting reconstruction bias was determined to be as low as 0.01 mm. These findings indicate that the proposed method is practical for surface reconstruction and its capabilities will be further enhanced through optical design improvements.
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A cubic metal exhibiting zero thermal expansion (ZTE) over a wide temperature window demonstrates significant applications in a broad range of advanced technologies but is extremely rare in nature. Here, enabled by high-temperature synthesis, we realize tunable thermal expansion via magnetic doping in the class of kagome cubic (Fd-3m) intermetallic (Zr,Nb)Fe2. A remarkably isotropic ZTE is achieved with a negligible coefficient of thermal expansion (+0.47 × 10-6 K-1) from 4 to 425 K, almost wider than most ZTE in metals available. A combined in situ magnetization, neutron powder diffraction, and hyperfine Mössbauer spectrum analysis reveals that interplanar ferromagnetic ordering contributes to a large magnetic compensation for normal lattice contraction upon cooling. Trace Fe-doping introduces extra magnetic exchange interactions that distinctly enhance the ferromagnetism and magnetic ordering temperature, thus engendering such an ultrawide ZTE. This work presents a promising ZTE in kagome metallic materials.
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A bacterial strain, designated S9-5T, was isolated from moraine samples collected from the north slope of Mount Everest at an altitude of 5â500 m above sea level. A polyphasic study confirmed the affiliation of the strain with the genus Sphingomonas. Strain S9-5T was an aerobic, Gram-stain-negative, non-spore-forming, non-motile and rod-shaped bacterium that could grow at 10-40 °C, pH 5-8 and with 0-9â% (w/v) NaCl. Q-10 was its predominant respiratory menaquinone. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminophospholipid and eight unidentified lipids comprised the polar lipids of strain S9-5T. Its major fatty acids were summed feature 8 (C18â:â1 ω7c and/or C18â:â1 ω6c) and C16â:â0. The G+C content was 65.75mol%. Phylogenetic analysis based on 16S rRNA sequences showed that strain S9-5T was phylogenetically closely related to Sphingomonas panaciterrae DCY91T (98.17â%), Sphingomonas olei K-1-16T (98.11â%) and Sphingomonas mucosissima DSM 17494T (97.39â%). The average nucleotide identity values among strain S9-5T and Sphingomonas panaciterrae DCY91T, Sphingomonas olei K-1-16T and Sphingomonas mucosissima DSM 17494T were 78.82, 78.87 and 78.29â%, respectively. Based on the morphological, physiological and chemotaxonomic data, strain S9-5T (=JCM 34750T=GDMCC 1.2714T) should represent a novel species of the genus Sphingomonas, for which we propose the name Sphingomonas radiodurans sp. nov.
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Sphingomonas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Microbiologia do SoloRESUMO
Sensitive H2 sensors at low concentrations and room temperature are desired for the early warning and control of hydrogen leakage. In this paper, a resistive sensor based on Pt-doped In2O3 nanoparticles was fabricated using inkjet printing process. The H2 sensing performance of the sensor was evaluated at low concentrations below 1% at room temperature. It exhibited a relative high response of 42.34% to 0.6% H2. As the relative humidity of 0.5% H2 decreased from 34% to 23%, the response decreased slightly from 34% to 23%. The sensing principle and the humidity effect were discussed. A dynamic current sensing model for dry H2 detection was proposed based on Wolkenstein theory and experimentally verified to be able to predict the sensing behavior of the sensor. The H2 concentration can be calculated within a short measurement time using the model without waiting for the saturation of the response, which significantly reduces the sensing and recovery time of the sensor. The sensor is expected to be a promising candidate for room-temperature H2 detection, and the proposed model could be very helpful in promoting the application of the sensor for real-time H2 leakage monitoring.
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Hidrogênio , Nanopartículas , Umidade , TemperaturaRESUMO
The critical behavior of the van der Waals ferromagnet Fe3.8GaTe2was systematically studied through measurements of isothermal magnetization, with the magnetic field applied along thec-axis. Fe3.8GaTe2undergoes a non-continuous paramagnetic to ferromagnetic phase transition at the Curie temperatureTcâ¼ 355 K. A comprehensive analysis of isotherms aroundTcutilizing the modified Arrott diagram, the Kouvel-Fisher method, the Widom scaling law, and the critical isotherm analysis yielded the critical exponent ofß= 0.411,γ= 1.246, andδ= 3.99. These critical exponents are found to be self-consistent and align well with the scaling equation at high magnetic fields, underscoring the reliability and intrinsic nature of these parameters. However, the low-field data deviates from the scaling relation, exhibiting a vertical trend whenT
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The quest for materials with non-collinear magnetic structures has been driven by their unique properties and potential applications in advanced spintronics and data storage technologies. In this study, we investigate the induction of a non-collinear conical state in BaFe12O19 (M-type) nanocrystal fibers through the substitution of Fe3+ ions with diamagnetic Sc3+ ions. This substitution introduces an additional parameter for tuning the magnetic structure and allows precise control over the substitution amount. We demonstrate that the non-collinear conical state remains stable within a temperature range of 125 K to 325 K and can be finely adjusted by varying the Sc3+ substitution amount. The selective occupancy of Sc3+ ions at the 2a, 4f2, and 2b sites within the M-type ferrite lattice weakens the super-exchange interaction between Fe1, Fe2, and Fe5 ions. This weakening disrupts interactions between different blocks S/R (R*/S*) and stabilizes the conical state. These findings highlight a significant approach to modulating non-collinear magnetic structures in hexagonal ferrites, with implications for both fundamental research and practical applications in the development of novel magnetic materials.
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The origin of the nematic order remains unclear due to the strong coupling between orbital, spin and lattice degrees of freedom in iron-based superconductors. Although the driving force of hole-doped BeFe2As2is still controversial, the nematic fluctuation of electron-doped compounds is generally believed to be spin fluctuation driven. Here, we present a comprehensive study of the nematic phase transition in Ba(Fe0.962Cu0.038)2As2single crystal by using Mössbauer spectroscopy. The electric field gradient and its in-plane asymmetry on Fe nucleus, which are directly determined by the occupation of individualt2gorbital, are sensitive to the local nematicity of Fe ions. The nematic phase transition happens atTnem≈ 73.8 K in the compound while the band splitting betweendxz/dyzorbitals begins far aboveTnemand reaches 18.8 meV at 30 K. The temperature evolution of the hyperfine parameters proves the existence of electron-phonon interaction and non-Fermi-liquid behaviour nearTnem. However, the spin-lattice relaxation signal is only evident belowTnem. These observations show that the role of orbital degrees of freedom is more active in driving nematicity than in Co- or Ni-doped BaFe2As2compounds, and can be attributed to enhanced electronic localization caused by Cu doping.
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The scarcity of two-dimensional (2D) magnetic nanostructures has hindered their applications in spintronics, which is attributed to that most magnetic materials exhibit non-van der Waals (nvdWs) structures and it is hard to reduce their thickness to 2D nanostructures. Thus it is necessary to develop a promising strategy for free-standing 2D magnetic nvdWs nanostructures. We have achieved free-standing 2D nvdWs hexagonal FeSe with a thickness of 2.9 nm by the reaction between the oleylamine-Se complex and Fe2+ with the assistance of Cl-, where the synergetic effects of Cl- and -NH2 lead to anisotropic growth. Inspiringly, the 2D hexagonal FeSe exhibits intrinsic antiferromagnetic order rooted in Fe2+ and semiconducting nature. In addition, the temperature variation would result in the chemical environment changes of Fe2+, responsible for the temperature-dependent magnetic transitions. This work promotes the potential applications of 2D hexagonal FeSe and the preparation of other 2D nvdWs materials.
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PURPOSE:: To evaluate the possibility of using peripheral-blood presurfactant protein B (Pro-SFTPB) for screening non-small cell lung cancer (NSCLC). METHODS:: A total of 873 healthy volunteers and 165 lung cancer patients hospitalized in the Fifth People's Hospital of Dalian were tested Pro-SFTPB once every half year from January 2014 to September 2015. The healthy volunteers were also conducted spiral computed tomography (CT) examination once every year. The data were then com-pared and statistically analyzed. RESULTS:: The positive expression rate of Pro-SFTPB in NSCLC was significantly higher than that in healthy volunteers, and significantly higher in lung adenocarcinoma than in squamous cell carcinoma; additionally, the expression rate was increased with the in-crease of smoking index, and the intergroup differences showed statistical signifi-cance (p≤0.05). The positive rate of newly diagnosed lung cancer was 29.55%, higher than healthy volunteers (22.34%), but there was no significant difference (p>0.05). CONCLUSION:: Pro-SFTPB is over expressed in non-small cell lung cancer, especially in lung adeno-carcinoma, but it can't be used as a clinical screening tool for lung cancer.
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Carcinoma Pulmonar de Células não Pequenas/sangue , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/diagnóstico , Precursores de Proteínas/sangue , Proteínas Associadas a Surfactantes Pulmonares/sangue , Idoso , Biomarcadores Tumorais/sangue , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Programas de Rastreamento , Sensibilidade e EspecificidadeRESUMO
Abstract Purpose: To evaluate the possibility of using peripheral-blood presurfactant protein B (Pro-SFTPB) for screening non-small cell lung cancer (NSCLC). Methods: A total of 873 healthy volunteers and 165 lung cancer patients hospitalized in the Fifth People's Hospital of Dalian were tested Pro-SFTPB once every half year from January 2014 to September 2015. The healthy volunteers were also conducted spiral computed tomography (CT) examination once every year. The data were then com-pared and statistically analyzed. Results: The positive expression rate of Pro-SFTPB in NSCLC was significantly higher than that in healthy volunteers, and significantly higher in lung adenocarcinoma than in squamous cell carcinoma; additionally, the expression rate was increased with the in-crease of smoking index, and the intergroup differences showed statistical signifi-cance (p≤0.05). The positive rate of newly diagnosed lung cancer was 29.55%, higher than healthy volunteers (22.34%), but there was no significant difference (p>0.05). Conclusion: Pro-SFTPB is over expressed in non-small cell lung cancer, especially in lung adeno-carcinoma, but it can't be used as a clinical screening tool for lung cancer.