Two-dimensional van der Waals materials have demonstrated fascinating optical and electrical characteristics. However, reports on magnetic properties and spintronic applications of van der Waals materials are scarce by comparison. Here, we report anomalous Hall effect measurements on single crystalline metallic Fe3GeTe2 nanoflakes with different thicknesses. These nanoflakes exhibit a single hard magnetic phase with a near square-shaped magnetic loop, large coercivity (up to 550 mT at 2 K), a Curie temperature near 200 K and strong perpendicular magnetic anisotropy. Using criticality analysis, the coupling length between van der Waals atomic layers in Fe3GeTe2 is estimated to be ~5 van der Waals layers. Furthermore, the hard magnetic behaviour of Fe3GeTe2 can be well described by a proposed model. The magnetic properties of Fe3GeTe2 highlight its potential for integration into van der Waals magnetic heterostructures, paving the way for spintronic research and applications based on these devices.

Transition-metal alloyed nanoparticles with core-shell features (shell enrichment by one of the metals) are becoming ubiquitous, from (electro-)catalysis to biomedical applications, due to their size control, performance, biocompatibility, and cost. We investigate 132 binary-alloyed nanoparticle systems (groups 8 to 11 in the Periodic Table) using density functional theory (DFT) and systematically explore their segregation energies to determine core-shell preferences. We find that core-shell preferences are generally described by two independent factors: (1) cohesive energy (related to vapor pressure) and (2) atomic size (quantified by the Wigner-Seitz radius), and the interplay between them. These independent factors are shown to provide general trends for the surface segregation preference for atoms in nanoparticles, as well as semi-infinite surfaces, and give a simple correlation (a "design map") for the alloying and catalytic behavior. Finally, we provide a universal description of core-shell preference via tight-binding theory (band-energy differences) that (i) quantitatively reproduces the DFT segregation energies and (ii) confirms the electronic origins and correlations for core-shell behavior.

The development of metamaterials, data processing circuits and sensors for the visible and ultraviolet parts of the spectrum is hampered by the lack of low-loss media supporting plasmonic excitations. This has driven the intense search for plasmonic materials beyond noble metals. Here we show that the semiconductor Bi 1.5 Sb 0.5 Te 1.8 Se 1.2 , also known as a topological insulator, is also a good plasmonic material in the blue-ultraviolet range, in addition to the already-investigated terahertz frequency range. Metamaterials fabricated from Bi 1.5 Sb 0.5 Te 1.8 Se 1.2 show plasmonic resonances from 350 to 550 nm, while surface gratings exhibit cathodoluminescent peaks from 230 to 1,050 nm. The observed plasmonic response is attributed to the combination of bulk charge carriers from interband transitions and surface charge carriers of the topological insulator. The importance of our result is in the identification of new mechanisms of negative permittivity in semiconductors where visible range plasmonics can be directly integrated with electronics.

In topological quantum materials 1-4 the conduction and valence bands are connected at points (Dirac/Weyl semimetals) or along lines (Line Node semimetals) in the momentum space. Numbers of studies demonstrated that several materials are indeed Dirac/Weyl semimetals 5-9 . However, there is still no experimental confirmation of materials with line nodes, in which the Dirac nodes form closed loops in the momentum space 2,4 . Here we report the discovery of a novel topological structureDirac node arcs -in the ultrahigh magnetoresistive material PtSn 4 using laser-based angle-resolved photoemission spectroscopy (ARPES) data and density functional theory (DFT) calculations. Unlike the closed loops of line nodes, the Dirac node arc structure resembles the Dirac dispersion in graphene 10 that is extended along one dimension in momentum space and confined by band gaps on either end. We propose that this reported Dirac node arc structure is a novel topological state that provides a novel platform for studying the exotic properties of Dirac Fermions.1 arXiv:1603.00934v1 [cond-mat.mtrl-sci]

IntroductionThe Isodon plant, Rabdosia rubescens (RR), and its extracts, were shown in China to be able to suppress disease progress, reduce tumor burden, alleviate syndrome, and prolong survival in patients with esophageal, gastric carcinoma or liver cancer. [1][2][3][4][5] Of interest, other Isodon plants including Isodon japonicus Hara (IJ) and I trichocarpus (IT) were also applied as home remedies for similar disorders in Japan and Korea. 6 Oridonin ( Figure 1A), a bitter tetracycline diterpenoid compound, was isolated from RR, IJ, and IT separately, 7,8 suggesting oridonin should be an essential antitumor component of Isodon plants. Studies showed that oridonin induced apoptosis in a variety of cancer cells including those from prostate, breast, non-small cell lung cancers, acute leukemia (NB4, HL-60 cells), glioblastoma multiforme, and human melanoma cells. [9][10][11][12] Oridonin could also increase lifespan of mice bearing Ehrlich ascites or P388 lymphocytic leukemia. 13,14 However, though studies showed that caspase-3 (casp-3), casp-8, P53, Bcl-2/Bax, cytochrome c (cyt C), 10,15,16 and nuclear factor kappa B (NFB) 17 were involved in apoptosis induced by oridonin, mechanisms underlying the antitumor activity of oridonin remain largely unknown, and whether oridonin can find clinical application still needs more investigation.Genetic abnormalities have been shown to play a key role in leukemogenesis, 18 and treatment strategies interfering with oncoproteins involved in leukemia pathogenesis have been reported to have high therapeutic efficacy with low adverse effects. The BCR-ABL-targeting STI-571, in the treatment of chronic myeloid leukemia (CML), 19 and the PML-RAR␣-targeting agents all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), in taming acute promyelocytic leukemia (APL), 20,21 can serve as paradigms. Hence molecular target-based therapies should be developed for leukemias with poor prognosis. The AML1-ETO (AE) fusion gene is the result of translocation t(8;21)(q22;q22), which is seen in 40% to 80% of M2-type acute myeloid leukemia (AML M2) and 12% to 20% of all cases of AML. 22,23 The AE fusion protein recruits the nuclear receptor corepressor (NCoR)-mammalian Sin3 (mSin3)-histone deacetylase (HDAC) complex, 24,25 inhibits transcription of AML1 target genes 22,24 including interleukin-3 (IL3), 26 activates transcription of apoptotic antagonist Bcl-2, 27 up-regulates protein tyrosine kinase C-KIT, 28 induces the expression of granulocyte colony-stimulating factor receptor (G-CSFR) as well as myeloperoxidase (MPO), 29 and blocks transactivation of the GM-CSF promoter. 30 The AE oncoprotein enhances self-renewal of hematopoietic stem/progenitor cells, blocks hematopoietic differentiation, disturbs normal cell proliferation, 31 and immortalizes murine hematopoietic progenitors. 32,33 Although reports suggest that additional mutations are required to cooperate with AE to cause murine The online version of this article contains a data supplement.The publication costs of this article were defr...

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Intermetallic compounds are garnering increasing attention as efficient catalysts for improved selectivity in chemical processes. Here, using a ship-in-a-bottle strategy, we synthesize single-phase platinum-based intermetallic nanoparticles (NPs) protected by a mesoporous silica (mSiO 2 ) shell by heterogeneous reduction and nucleation of Sn, Pb, or Zn in mSiO 2 -encapsulated Pt NPs. For selective hydrogenation of furfural to furfuryl alcohol, a dramatic increase in activity and selectivity is observed when intermetallic NPs catalysts are used in comparison to Pt@mSiO 2 . Among the intermetallic NPs, PtSn@mSiO 2 exhibits the best performance, requiring only one-tenth of the quantity of Pt used in Pt@mSiO 2 for similar activity and near 100% selectivity to furfuryl alcohol. A high-temperature oxidation-reduction treatment easily reverses any carbon deposition-induced catalyst deactivation. X-ray photoelectron spectroscopy shows the importance of surface composition to the activity, whereas density functional theory calculations reveal that the enhanced selectivity on PtSn compared to Pt is due to the different furfural adsorption configurations on the two surfaces. ABSTRACT: Intermetallic compounds are garnering increasing attention as efficient catalysts for improved selectivity in chemical processes. Here, using a ship-in-a-bottle strategy, we synthesize single-phase platinum-based intermetallic nanoparticles (NPs) protected by a mesoporous silica (mSiO 2 ) shell by heterogeneous reduction and nucleation of Sn, Pb, or Zn in mSiO 2 -encapsulated Pt NPs. For selective hydrogenation of furfural to furfuryl alcohol, a dramatic increase in activity and selectivity is observed when intermetallic NPs catalysts are used in comparison to Pt@mSiO 2 . Among the intermetallic NPs, PtSn@mSiO 2 exhibits the best performance, requiring only one-tenth of the quantity of Pt used in Pt@mSiO 2 for similar activity and near 100% selectivity to furfuryl alcohol. A hightemperature oxidation−reduction treatment easily reverses any carbon deposition-induced catalyst deactivation. X-ray photoelectron spectroscopy shows the importance of surface composition to the activity, whereas density functional theory calculations reveal that the enhanced selectivity on PtSn compared to Pt is due to the different furfural adsorption configurations on the two surfaces.

The study provided new insights into the role of miRNAs and their target genes in the pathogenesis of fetal alcohol syndrome.