Magnetochiral tunneling in paramagnetic Co1/3NbS2.

Electric currents have the intriguing ability to induce magnetization in nonmagnetic crystals with sufficiently low crystallographic symmetry. Some associated phenomena include the non-linear anomalous Hall effect in polar crystals and the nonreciprocal directional dichroism in chiral crystals when magnetic fields are applied. In this work, we demonstrate that the same underlying physics is also manifested in the electronic tunneling process between the surface of a nonmagnetic chiral material and a magnetized scanning probe. In the paramagnetic but chiral metallic compound Co1/3NbS2, the magnetization induced by the tunneling current is shown to become detectable by its coupling to the magnetization of the tip itself. This results in a contrast across different chiral domains, achieving atomic-scale spatial resolution of structural chirality. To support the proposed mechanism, we used first-principles theory to compute the chirality-dependent current-induced magnetization and Berry curvature in the bulk of the material. Our demonstration of this magnetochiral tunneling effect opens up an avenue for investigating atomic-scale variations in the local crystallographic symmetry and electronic structure across the structural domain boundaries of low-symmetry nonmagnetic crystals.

Monoclinic LaSb2 Superconducting Thin Films.

Rare-earth diantimondes exhibit coupling between structural and electronic orders, which are tunable under pressure and temperature. Here we present the discovery of a new polymorph of LaSb2 stabilized in thin films synthesized using molecular beam epitaxy. Using diffraction, electron microscopy, and first-principles calculations we identify a YbSb2-type monoclinic lattice as a yet-uncharacterized stacking configuration. The material hosts superconductivity with a Tc = 2 K, which is enhanced relative to the bulk ambient phase, and a long superconducting coherence length of 1730 Å. This result highlights the potential thin film growth has in stabilizing novel stacking configurations in quasi-two-dimensional compounds with competing layered structures.

Direct Visualization of Surface Spin-Flip Transition in MnBi_{4}Te_{7}.

We report direct visualization of spin-flip transition of the surface layer in antiferromagnet MnBi_{4}Te_{7}, a natural superlattice of alternating MnBi_{2}Te_{4} and Bi_{2}Te_{3} layers, using cryogenic magnetic force microscopy (MFM). The observation of magnetic contrast across domain walls and step edges confirms that the antiferromagnetic order persists to the surface layers. The magnetic field dependence of the MFM images reveals that the surface magnetic layer undergoes a first-order spin-flip transition at a magnetic field that is lower than the bulk transition, in excellent agreement with a revised Mills model. Our analysis suggests no reduction of the order parameter in the surface magnetic layer, implying robust ferromagnetism in the single-layer limit. The direct visualization of surface spin-flip transition not only opens up exploration of surface metamagnetic transitions in layered antiferromagnets, but also provides experimental support for realizing quantized transport in ultrathin films of MnBi_{4}Te_{7} and other natural superlattice topological magnets.

Wide angle holographic video projection display.

Holographic projection displays provide high diffraction efficiency. However, they have a limited projection angle. This work proposes a holographic projection display with a wide angle, which gives an image of size 306mm×161mm at 700 mm and reduced speckle noise. The solution uses single Fourier lens imaging with a frequency filter and hologram generation utilizing complex coding and nonparaxial diffraction. The experiment was performed with a 4K phase-only spatial light modulator (SLM) to prove the high efficiency of the developed numerical tools. Optical reconstruction shows high resolution and high image quality achieved from a single frame. Hence, displaying video at a full frame rate of the SLM is possible.

Selaginellin Derivatives from Selaginella tamariscina and Their Upregulating Effects on Low-Density Lipoprotein Receptor Expression.

Two new dimeric selaginellins, diselaginellins C and D (1 and 2), a new unusual derivative, selapiginellin A (4), a new selaginpulvilin U (5), and a known derivative, diselaginellin A (3), were isolated from Selaginella tamariscina (P. Beauv.) Spring. Among these compounds, selapiginellin A (4) is the first naturally occurring compound comprising an ether-linked dimer of a selaginellin and a selaginpulvilin. The absolute configurations of 1, 2, and 4 were elucidated by spectroscopic data analyses. Compound 5 was found to regulate mRNA expression of the low-density lipoprotein receptor (LDLR) gene and LDLR-related genes.

Robust Extrinsic Calibration of Multiple RGB-D Cameras with Body Tracking and Feature Matching.

RGB-D cameras have been commercialized, and many applications using them have been proposed. In this paper, we propose a robust registration method of multiple RGB-D cameras. We use a human body tracking system provided by Azure Kinect SDK to estimate a coarse global registration between cameras. As this coarse global registration has some error, we refine it using feature matching. However, the matched feature pairs include mismatches, hindering good performance. Therefore, we propose a registration refinement procedure that removes these mismatches and uses the global registration. In an experiment, the ratio of inliers among the matched features is greater than 95% for all tested feature matchers. Thus, we experimentally confirm that mismatches can be eliminated via the proposed method even in difficult situations and that a more precise global registration of RGB-D cameras can be obtained.

Prenylated Flavonoid Glycosides with PCSK9 mRNA Expression Inhibitory Activity from the Aerial Parts of Epimedium koreanum.

Phytochemical investigation on the n-BuOH-soluble fraction of the aerial parts of Epimedium koreanum using the PCSK9 mRNA monitoring assay led to the identification of four previously undescribed acylated flavonoid glycosides and 18 known compounds. The structures of new compounds were elucidated by NMR, MS, and other chemical methods. All isolated compounds were tested for their inhibitory activity against PCSK9 mRNA expression in HepG2 cells. Of the isolates, compounds 6, 7, 10, 15, and 17-22 were found to significantly inhibit PCSK9 mRNA expression. In particular, compound 7 was shown to increase LDLR mRNA expression. Thus, compound 7 may potentially increase LDL uptake and lower cholesterol levels in the blood.

New compression method for full-complex holograms using the modified zerotree algorithm with the adaptive discrete wavelet transform.

In this paper, we propose a new method for coding a full complex hologram with random phase. Since holograms with random phase have very unique spatial and frequency characteristics, a new compression method suitable for such holograms is required. We analyze the frequency characteristics of holograms with random phases and propose a new adaptive discrete wavelet transform (aDWT). Next, we propose a new modified zerotree alogrithm (mZTA) suitable for the subband configuration generated by the modified wavelet transform method. The results of the compression using the proposed method showed higher efficiency than the previous method, and the reconstructed images showed visually superior results.

Engineering Weyl Phases and Nonlinear Hall Effects in T_{d}-MoTe_{2}.

MoTe_{2} has recently attracted much attention due to the observation of pressure-induced superconductivity, exotic topological phase transitions, and nonlinear quantum effects. However, there has been debate on the intriguing structural phase transitions among various observed phases of MoTe_{2} and their connection to the underlying topological electronic properties. In this work, by means of density-functional theory calculations, we investigate the structural phase transition between the polar T_{d} and nonpolar 1T^{'} phases of MoTe_{2} in reference to a hypothetical high-symmetry T_{0} phase that exhibits higher-order topological features. In the T_{d} phase we obtain a total of 12 Weyl points, which can be created/annihilated, dynamically manipulated, and switched by tuning a polar phonon mode. We also report the existence of a tunable nonlinear Hall effect in T_{d}-MoTe_{2} and propose the use of this effect as a probe for the detection of polarity orientation in polar (semi)metals. By studying the role of dimensionality, we identify a configuration in which a nonlinear surface response current emerges. The potential technological applications of the tunable Weyl phase and the nonlinear Hall effect are discussed.

Robust A-Type Order and Spin-Flop Transition on the Surface of the Antiferromagnetic Topological Insulator MnBi_{2}Te_{4}.

Here, we present microscopic evidence of the persistence of uniaxial A-type antiferromagnetic order to the surface layers of MnBi_{2}Te_{4} single crystals using magnetic force microscopy. Our results reveal termination-dependent magnetic contrast across both surface step edges and domain walls, which can be screened by thin layers of soft magnetism. The robust surface A-type order is further corroborated by the observation of termination-dependent surface spin-flop transitions, which have been theoretically proposed decades ago. Our results not only provide key ingredients for understanding the electronic properties of the antiferromagnetic topological insulator MnBi_{2}Te_{4}, but also open a new paradigm for exploring intrinsic surface metamagnetic transitions in natural antiferromagnets.

Glucose Uptake-Stimulating Galloyl Ester Triterpenoids from Castanopsis sieboldii.

Using molecular networking-guided isolation, three new galloyl ester triterpenoids (1-3), two new hexahydroxydiphenic acid-conjugated triterpenoids (6 and 7), and four known compounds (4, 5, 8, and 9) were isolated from the fruits and leaves of Castanopsis sieboldii. The chemical structures of 1-3, 6, and 7 were elucidated on the basis of interpreting their NMR, HRESIMS, and ECD spectra. All compounds (1-9) were evaluated for their glucose uptake-stimulating activities in differentiated adipocytes using 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-d-glucose as a fluorescent-tagged glucose probe. Compounds 2 and 9 resulted in a 1.5-fold increase in glucose uptake. Among them, compound 2 from the fruits showed an upregulation of p-AMPK/AMPK ratio in differentiated C2C12 myoblasts to support the mechanism proposed of glucose uptake stimulation.

Discovery of 5-methyl-N-(2-arylquinazolin-7-yl)isoxazole-4-carboxamide analogues as highly selective FLT3 inhibitors.

A series of 4-arylamido 5-methylisoxazole derivatives with quinazoline core was designed and synthesised based on conformational rigidification of a previous type II FMS inhibitor. Most of quinazoline analogues displayed activity against FLT3 and FLT3-ITD. Compound 7d, 5-methyl-N-(2-(3-(4-methylpiperazin-1-yl)-5-(trifluoromethyl)phenyl)quinazolin-7-yl)isoxazole-4-carboxamide, exhibited the most potent inhibitory activity against FLT3 (IC50= 106 nM) with excellent selectivity profiles over 36 other protein kinases including cKit and FMS kinase. Compound 7d was also active in FLT-ITD, with an IC50 value of 301 nM, and other FLT3 mutants showing potential as an AML therapeutics.

Development of Real-Time Hand Gesture Recognition for Tabletop Holographic Display Interaction Using Azure Kinect.

The use of human gesturing to interact with devices such as computers or smartphones has presented several problems. This form of interaction relies on gesture interaction technology such as Leap Motion from Leap Motion, Inc, which enables humans to use hand gestures to interact with a computer. The technology has excellent hand detection performance, and even allows simple games to be played using gestures. Another example is the contactless use of a smartphone to take a photograph by simply folding and opening the palm. Research on interaction with other devices via hand gestures is in progress. Similarly, studies on the creation of a hologram display from objects that actually exist are also underway. We propose a hand gesture recognition system that can control the Tabletop holographic display based on an actual object. The depth image obtained using the latest Time-of-Flight based depth camera Azure Kinect is used to obtain information about the hand and hand joints by using the deep-learning model CrossInfoNet. Using this information, we developed a real time system that defines and recognizes gestures indicating left, right, up, and down basic rotation, and zoom in, zoom out, and continuous rotation to the left and right.

Ferromagnetic Anomalous Hall Effect in Cr-Doped Bi2Se3 Thin Films via Surface-State Engineering.

The anomalous Hall effect (AHE) is a nonlinear Hall effect appearing in magnetic conductors, boosted by internal magnetism beyond what is expected from the ordinary Hall effect. With the recent discovery of the quantized version of the AHE, the quantum anomalous Hall effect (QAHE), in Cr- or V-doped topological insulator (TI) (Sb,Bi)2Te3 thin films, the AHE in magnetic TIs has been attracting significant interest. However, one of the puzzles in this system has been that while Cr- or V-doped (Sb,Bi)2Te3 and V-doped Bi2Se3 exhibit AHE, Cr-doped Bi2Se3 has failed to exhibit even ferromagnetic AHE, the expected predecessor to the QAHE, though it is the first material predicted to exhibit the QAHE. Here, we have successfully implemented ferromagnetic AHE in Cr-doped Bi2Se3 thin films by utilizing a surface state engineering scheme. Surprisingly, the observed ferromagnetic AHE in the Cr-doped Bi2Se3 thin films exhibited only a positive slope regardless of the carrier type. We show that this sign problem can be explained by the intrinsic Berry curvature of the system as calculated from a tight-binding model combined with a first-principles method.

Combined MS/MS-NMR Annotation Guided Discovery of Iris lactea var. chinensis Seed as a Source of Viral Neuraminidase Inhibitory Polyphenols.

In this study, the chemical diversity of polyphenols in Iris lactea var. chinensis seeds was identified by combined MS/MS-NMR analysis. Based on the annotated chemical profile, the isolation of stilbene oligomers was conducted, and consequently, stilbene oligomers (1-10) were characterized. Of these, compounds 1 and 2 are previously undescribed stilbene dimer glycoside (1) and tetramer glycoside (2), respectively. Besides, to evaluate this plant seed as a rich source of stilbene oligomers, we quantified three stilbene oligomers of I. lactea var. chinensis seeds. The contents of three major stilbene oligomers-trans-ε-viniferin (3), vitisin A (6), and vitisin B (9)-in I. lactea var. chinensis seeds were quantified as 2.32 (3), 4.95 (6), and 1.64 (9) mg/g dry weight (DW). All the isolated compounds were tested for their inhibitory activities against influenza neuraminidase. Compound 10 was found to be active with the half maximal inhibitory concentration (IC50) values at 4.76 µM. Taken together, it is concluded that I. lactea var. chinensis seed is a valuable source of stilbene oligomers with a human health benefit.

Design, synthesis, and in vitro evaluation of N-(3-(3-alkyl-1H-pyrazol-5-yl) phenyl)-aryl amide for selective RAF inhibition.

Notorious oncogenic BRAF V600E plays a significant role in the signal transduction of the MAPK pathway, which is involved in tumor growth, especially in melanoma. Much effort has been made to suppress BRAF V600E through small molecules like vemurafenib and dabrafenib, but the MAPK pathway remains active through paradoxical activation, where CRAF transmits the signal of the MAPK pathway either alone or along with BRAF V600E. Therefore, we designed and synthesized a new series of N-(3-(3-alkyl-1H-pyrazol-5-yl) phenyl)-aryl amide/urea analogues that showed potent inhibitory activities against BRAF V600E and CRAF. Compound 7c exhibited particularly superior selectivity toward BRAF V600E and CRAF over 30 other protein kinases, implying that this chemotype could be investigated as a BRAF paradox breaker. © 2019 Elsevier Ltd. All rights reserved.

Molecular Networking Reveals the Chemical Diversity of Selaginellin Derivatives, Natural Phosphodiesterase-4 Inhibitors from Selaginella tamariscina.

Selaginellins are unique pigments found in the genus Selaginella, the largest genus of Lycopodiophyta. Recent studies reported that some selaginellin analogues have potent phosphodiesterase-4 (PDE4) inhibitory activity. In this study, the chemical diversity of natural selaginellin derivatives was revealed by an MS/MS molecular networking-based dereplication of the Selaginella tamariscina extract. It led to the prioritization of chromatographic peaks predicted as previously unknown selaginellin derivatives. Targeted isolation of these compounds afforded two unusual selaginellin analogues with a 1H,3H-dibenzo[de,h]isochromene skeleton, namely, selariscins A (1) and B (2), along with eight new diarylfluorene derivatives, selaginpulvilins M-T (3-10), and five known analogues, 11-15. The absolute configurations of 1, 2, and 8-10 were elucidated by spectroscopic data analyses including computational electronic circular dichroism data. Compounds 1 and 3-10 showed PDE4 inhibitory activity with IC50 values in the range of 2.8-33.8 µM, and their binding modes are suggested by a molecular docking study.

Prenylated Flavonoids from the Roots and Rhizomes of Sophora tonkinensis and Their Effects on the Expression of Inflammatory Mediators and Proprotein Convertase Subtilisin/Kexin Type 9.

Seven new prenylated flavonoids (1-7) and one new prenylated phenylpropiophenone (8) were isolated from roots and rhizomes of Sophora tonkinensis, along with nine known compounds (9-17). The structures 1-8 were elucidated by spectroscopic data analysis and comparison with reported values. Compounds 8 and 12 (7-methoxyebenosin) showed inhibitory activities against nitric oxide production in lipopolysaccharide-induced RAW264.7 cells, with IC50 values of 8.1 and 6.2 µM, respectively. They also significantly lowered expression of CSF2, TNF, and IL-1ß. Lonchocarpol A (10) and erybraedin D (16) at concentrations of 20 µM downregulated proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA expression in HepG2 cells. Moreover, erybraedin D (16) inhibited PCSK9 protein synthesis (IC50 7.8 µM), while simultaneously activating AMP-activated protein kinase and acetyl-CoA carboxylase.

Eudesmane Glycosides from Ambrosia artemisiifolia (Common Ragweed) as Potential Neuroprotective Agents.

In Alzheimer's disease, amyloid-ß (Aß) accumulation in the brain results in neuronal cell death and is one of the major causes of dementia. Because the current therapeutic agents are not yet sufficiently effective or safe, there have been attempts to find new neuroprotective chemicals against Aß-induced cytotoxicity. A 70% EtOH extract of whole plants of Ambrosia artemisiifolia (common ragweed) was selected after the screening of a natural extract library. Seven new eudesmane-type glycosides (1-7) and seven known compounds (8-14) were obtained through bioactivity-guided fractionation from the aerial parts of this plant. Their structures were determined on the basis of their nuclear magnetic resonance spectra, high-resolution electrospray ionization mass spectrometry analysis, and electronic circular dichroism calculations. Among them, compounds 1, 2, 4-6, 8, 9, 11, 13, and 14 showed protective effects against Aß-induced cytotoxicity in Aß42-transfected HT22 cells. The most active compounds, 5 and 6, exhibited moderate protective activity dose-dependently (10, 20, and 40 µM).

Fourier digital holography of real scenes for 360° tabletop holographic displays.

Recently, the tabletop holographic display has been introduced to present a large 3D hologram floating over the table. When the observer looks down at the hologram, the display reconstructs upper perspectives of the object at a 45° angle. This paper presents the full imaging chain for the tabletop holographic display based on capture, processing, and reconstruction of a 360° observable hologram of the real object. Two different imaging methods, which involve lensless Fourier digital holographic recordings and the tabletop holographic display, are introduced. The first method utilizes the conventional capture approach with a side view perspective and numerical tilt correction for 45° angular mismatch between the acquisition and reconstruction systems. The second method presents a modified lensless digital Fourier holography for holographic recording of the upper perspective. Experimental results including numerical and optical reconstructions present various visual aspects of both capture approaches such as viewpoint correction, refocusing, 3D effects, and 3D deformations.