274 research outputs found
Evidence of Ising pairing in superconducting NbSe atomic layers
Two-dimensional transition metal dichalcogenides with strong spin-orbit
interactions and valley-dependent Berry curvature effects have attracted
tremendous recent interests. Although novel single-particle and excitonic
phenomena related to spin-valley coupling have been extensively studied,
effects of spin-momentum locking on collective quantum phenomena remain
unexplored. Here we report an observation of superconducting monolayer NbSe
with an in-plane upper critical field over six times of the Pauli paramagnetic
limit by magneto-transport measurements. The effect can be understood in terms
of the competing Zeeman effect and large intrinsic spin-orbit interactions in
non-centrosymmetric NbSe monolayers, where the electronic spin is locked to
the out-of-plane direction. Our results provide a strong evidence of
unconventional Ising pairing protected by spin-momentum locking and open up a
new avenue for studies of non-centrosymmetric superconductivity with unique
spin and valley degrees of freedom in the exact two-dimensional limit
Deep Learning Methods for Calibrated Photometric Stereo and Beyond
Photometric stereo recovers the surface normals of an object from multiple
images with varying shading cues, i.e., modeling the relationship between
surface orientation and intensity at each pixel. Photometric stereo prevails in
superior per-pixel resolution and fine reconstruction details. However, it is a
complicated problem because of the non-linear relationship caused by
non-Lambertian surface reflectance. Recently, various deep learning methods
have shown a powerful ability in the context of photometric stereo against
non-Lambertian surfaces. This paper provides a comprehensive review of existing
deep learning-based calibrated photometric stereo methods. We first analyze
these methods from different perspectives, including input processing,
supervision, and network architecture. We summarize the performance of deep
learning photometric stereo models on the most widely-used benchmark data set.
This demonstrates the advanced performance of deep learning-based photometric
stereo methods. Finally, we give suggestions and propose future research trends
based on the limitations of existing models.Comment: 19 pages, 11 figures, 4 table
Anthracenedione Derivatives as Anticancer Agents Isolated from Secondary Metabolites of the Mangrove Endophytic Fungi
In this article, we report anticancer activity of 14 anthracenedione derivatives separated from the secondary metabolites of the mangrove endophytic fungi Halorosellinia sp. (No. 1403) and Guignardia sp. (No. 4382). Some of them inhibited potently the growth of KB and KBv200 cells, among which compound 6 displayed strong cytotoxicity with IC50 values of 3.17 and 3.21 μM to KB and KBv200 cells, respectively. Furthermore, we demonstrate that the mechanism involved in the apoptosis induced by compound 6 is probably related to mitochondrial dysfunction. Additionally, the structure-activity relationships of these compounds are discussed
Searches for Interstellar HCCSH and H₂CCS
A longstanding problem in astrochemistry is the inability of many current models to account for missing sulfur content. Many relatively simple species that may be good candidates to sequester sulfur have not been measured experimentally at the high spectral resolution necessary to enable radioastronomical identification. On the basis of new laboratory data, we report searches for the rotational lines in the microwave, millimeter, and submillimeter regions of the sulfur-containing hydrocarbon HCCSH. This simple species would appear to be a promising candidate for detection in space owing to the large dipole moment along its b-inertial axis, and because the bimolecular reaction between two highly abundant astronomical fragments (CCH and SH radicals) may be rapid. An inspection of multiple line surveys from the centimeter to the far-infrared toward a range of sources from dark clouds to high-mass star-forming regions, however, resulted in nondetections. An analogous search for the lowest-energy isomer, H₂CCS, is presented for comparison, and also resulted in nondetections. Typical upper limits on the abundance of both species relative to hydrogen are 10^(−9)–10^(−10). We thus conclude that neither isomer is a major reservoir of interstellar sulfur in the range of environments studied. Both species may still be viable candidates for detection in other environments or at higher frequencies, providing laboratory frequencies are available
Work functions, ionization potentials, and in-between: Scaling relations based on the image charge model
We revisit a model in which the ionization energy of a metal particle is
associated with the work done by the image charge force in moving the electron
from infinity to a small cut-off distance just outside the surface. We show
that this model can be compactly, and productively, employed to study the size
dependence of electron removal energies over the range encompassing bulk
surfaces, finite clusters, and individual atoms. It accounts in a
straightforward manner for the empirically known correlation between the atomic
ionization potential (IP) and the metal work function (WF), IP/WF2. We
formulate simple expressions for the model parameters, requiring only a single
property (the atomic polarizability or the nearest neighbor distance) as input.
Without any additional adjustable parameters, the model yields both the IP and
the WF within 10% for all metallic elements, as well as matches the size
evolution of the ionization potentials of finite metal clusters for a large
fraction of the experimental data. The parametrization takes advantage of a
remarkably constant numerical correlation between the nearest-neighbor distance
in a crystal, the cube root of the atomic polarizability, and the image force
cutoff length. The paper also includes an analytical derivation of the relation
of the outer radius of a cluster of close-packed spheres to its geometric
structure.Comment: Original submission: 8 pages with 7 figures incorporated in the text.
Revised submission (added one more paragraph about alloy work functions): 18
double spaced pages + 8 separate figures. Accepted for publication in PR
Chromosomal end fusion resulting from telomere erosion increases susceptibility to radiation via multinucleation: Effect of p53
and telomerase activation are frequently found in human cancers. p53 inactivation, however, eliminates or attenuates the biological responses to telomerase inhibition and the eventual telomere erosion. We show that telomere erosion can increase the susceptibility to radiation, irrespective of p53 status. Both telomerase inhibition and critically shortened telomere with significant change of chromosomal end-to-end fusion were essential for the enhancement of radiosensitivity. The enhancement was correlated with greater formation of multinucleated cells. p53 inactivation did not eliminate the observed generation of chromosomal fusion and multinucleation, and the resulting increased susceptibility to radiation, as opposed to the previously proved role of p53 in mediating cellular responses to telomere dysfunction. The present findings suggest the importance of chromosomal end fusion in modulating radiosensitivity rather than p53 DNA damage signaling. Thus, the suggested anticancer radiotherapeutic strategy combined with telomerase inhibition could clinically be applicable to cancers, irrespective of p53 status.We thank Professor Woon Ki Paik for critical reading of the
manuscript and Eun-Ju Lee for assistance in the preparation
of the manuscript. This work was supported by a grant from
National Nuclear R&D program and Human Genome Project
(FG-1-1), Korean Ministry of Science and Technology
Data Driven Crowd Motion Control with Multi-touch Gestures
Controlling a crowd using multi‐touch devices appeals to the computer games and animation industries, as such devices provide a high‐dimensional control signal that can effectively define the crowd formation and movement. However, existing works relying on pre‐defined control schemes require the users to learn a scheme that may not be intuitive. We propose a data‐driven gesture‐based crowd control system, in which the control scheme is learned from example gestures provided by different users. In particular, we build a database with pairwise samples of gestures and crowd motions. To effectively generalize the gesture style of different users, such as the use of different numbers of fingers, we propose a set of gesture features for representing a set of hand gesture trajectories. Similarly, to represent crowd motion trajectories of different numbers of characters over time, we propose a set of crowd motion features that are extracted from a Gaussian mixture model. Given a run‐time gesture, our system extracts the K nearest gestures from the database and interpolates the corresponding crowd motions in order to generate the run‐time control. Our system is accurate and efficient, making it suitable for real‐time applications such as real‐time strategy games and interactive animation controls
Searches for Interstellar HCCSH and H₂CCS
A longstanding problem in astrochemistry is the inability of many current models to account for missing sulfur content. Many relatively simple species that may be good candidates to sequester sulfur have not been measured experimentally at the high spectral resolution necessary to enable radioastronomical identification. On the basis of new laboratory data, we report searches for the rotational lines in the microwave, millimeter, and submillimeter regions of the sulfur-containing hydrocarbon HCCSH. This simple species would appear to be a promising candidate for detection in space owing to the large dipole moment along its b-inertial axis, and because the bimolecular reaction between two highly abundant astronomical fragments (CCH and SH radicals) may be rapid. An inspection of multiple line surveys from the centimeter to the far-infrared toward a range of sources from dark clouds to high-mass star-forming regions, however, resulted in nondetections. An analogous search for the lowest-energy isomer, H₂CCS, is presented for comparison, and also resulted in nondetections. Typical upper limits on the abundance of both species relative to hydrogen are 10^(−9)–10^(−10). We thus conclude that neither isomer is a major reservoir of interstellar sulfur in the range of environments studied. Both species may still be viable candidates for detection in other environments or at higher frequencies, providing laboratory frequencies are available
Vandetanib (Zactima, ZD6474) Antagonizes ABCC1- and ABCG2-Mediated Multidrug Resistance by Inhibition of Their Transport Function
ABCC1 and ABCG2 are ubiquitous ATP-binding cassette transmembrane proteins that play an important role in multidrug resistance (MDR). In this study, we evaluated the possible interaction of vandetanib, an orally administered drug inhibiting multiple receptor tyrosine kinases, with ABCC1 and ABCG2 in vitro.MDR cancer cells overexpressing ABCC1 or ABCG2 and their sensitive parental cell lines were used. MTT assay showed that vandetanib had moderate and almost equal-potent anti-proliferative activity in both sensitive parental and MDR cancer cells. Concomitant treatment of MDR cells with vandetanib and specific inhibitors of ABCC1 or ABCG2 did not alter their sensitivity to the former drug. On the other hand, clinically attainable but non-toxic doses of vandetanib were found to significantly enhance the sensitivity of MDR cancer cells to ABCC1 or ABCG2 substrate antitumor drugs. Flow cytometric analysis showed that vandetanib treatment significantly increase the intracellular accumulation of doxorubicin and rhodamine 123, substrates of ABCC1 and ABCG2 respectively, in a dose-dependent manner (P<0.05). However, no significant effect was shown in sensitive parental cell lines. Reverse transcription-PCR and Western blot analysis showed that vandetanib did not change the expression of ABCC1 and ABCG2 at both mRNA and protein levels. Furthermore, total and phosphorylated forms of AKT and ERK1/2 remained unchanged after vandetanib treatment in both sensitive and MDR cancer cells.Vandetanib is unlikely to be a substrate of ABCC1 or ABCG2. It overcomes ABCC1- and ABCG2-mediated drug resistance by inhibiting the transporter activity, independent of the blockade of AKT and ERK1/2 signal transduction pathways
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