Tungsten diselenide (WSe2) and related transition metal dichalcogenides exhibit interesting optoelectronic properties owing to their peculiar band structures originating from the valley degree of ...freedom. Although the optical generation and detection of valley polarization has been demonstrated, it has been difficult to realize active valley-dependent functions suitable for device applications. We report an electrically switchable, circularly polarized light source based on the material's valley degree of freedom. Our WSe2-based ambipolar transistors emit circularly polarized electroluminescence from p-i-n junctions electrostatically formed in transistor channels. This phenomenon can be explained qualitatively by the electron-hole overlap controlled by the in-plane electric field. Our device demonstrates a route to exploit the valley degree of freedom and the possibility to develop a valley-optoelectronics technology.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
This paper tests the proposition that politicians and their affiliated firms (i.e., firms operating in their province) temporarily suppress negative information in response to political incentives. ...We examine the stock price behavior of Chinese listed firms around two visible political events—meetings of the National Congress of the Chinese Communist Party and promotions of high-level provincial politicians—that are expected to asymmetrically increase the costs of releasing bad news. The costs create an incentive for local politicians and their affiliated firms to temporarily restrict the flow of negative information about the companies. The result will be fewer stock price crashes for the affiliated firms during these event windows, followed by an increase in crashes after the event. Consistent with these predictions, we find that the affiliated firms experience a reduction (an increase) in negative stock return skewness before (after) the event. These effects are strongest in the three-month period directly preceding the event, among firms that are more politically connected, and when the province is dominated by faction politics and cronyism. Additional tests document a significant reduction in published newspaper articles about affected firms in advance of these political events, suggestive of a link between our observed stock price behavior and temporary shifts in the listed firms' information environment.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
The molecular mechanism underlying gastric cancer (GC) invasion and metastasis is still poorly understood. In this study, we tried to investigate the roles of CXCR4 and CXCR2 signalings in gastric ...cancer metastasis. A highly invasive gastric cancer cell model was established. Chemokines receptors were profiled to search for the accountable ones. Then the underlying molecular mechanism was investigated using both in vitro and in vivo techniques, and the clinical relevance of CXCR4 and CXCR2 expression was studied in gastric cancer samples. CXCR4 and CXCR2 were highly expressed in a high invasive gastric cancer cell model and in gastric cancer tissues. Overexpression of CXCR4 and CXCR2 was associated with more advanced tumor stage and poorer survival for GC patients. CXCR4 and CXCR2 expression strongly correlated with each other in the way that CXCR2 expression changed accordingly with the activity of CXCR4 signaling and CXCR4 expression also changed in agreement with CXCR2 activity. Further studies demonstrated CXCR4 and CXCR2 can both activated NF-κB and STAT3 signaling, while NF-κBp65 can then transcriptionally activate CXCR4 and STAT3 can activate CXCR2 expression. This crosstalk between CXCR4 and CXCR2 contributed to EMT, migration and invasion of gastric cancer. Finally, Co-inhibition of CXCR4 and CXCR2 is more effective in reducing gastric cancer metastasis. Our results demonstrated that CXCR4 and CXCR2 cross-activate each other to promote the metastasis of gastric cancer.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Single-layer transition-metal dichalcogenides (TMDs) receive significant attention due to their intriguing physical properties for both fundamental research and potential applications in electronics, ...optoelectronics, spintronics, catalysis, and so on. Here, we demonstrate the epitaxial growth of high-quality single-crystal, monolayer platinum diselenide (PtSe2), a new member of the layered TMDs family, by a single step of direct selenization of a Pt(111) substrate. A combination of atomic-resolution experimental characterizations and first-principle theoretic calculations reveals the atomic structure of the monolayer PtSe2/Pt(111). Angle-resolved photoemission spectroscopy measurements confirm for the first time the semiconducting electronic structure of monolayer PtSe2 (in contrast to its semimetallic bulk counterpart). The photocatalytic activity of monolayer PtSe2 film is evaluated by a methylene-blue photodegradation experiment, demonstrating its practical application as a promising photocatalyst. Moreover, circular polarization calculations predict that monolayer PtSe2 has also potential applications in valleytronics.
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IJS, KILJ, NUK, PNG, UL, UM
Organic aerosol (OA) data acquired by the Aerosol Mass Spectrometer (AMS) in 37 field campaigns were deconvolved into hydrocarbon‐like OA (HOA) and several types of oxygenated OA (OOA) components. ...HOA has been linked to primary combustion emissions (mainly from fossil fuel) and other primary sources such as meat cooking. OOA is ubiquitous in various atmospheric environments, on average accounting for 64%, 83% and 95% of the total OA in urban, urban downwind, and rural/remote sites, respectively. A case study analysis of a rural site shows that the OOA concentration is much greater than the advected HOA, indicating that HOA oxidation is not an important source of OOA, and that OOA increases are mainly due to SOA. Most global models lack an explicit representation of SOA which may lead to significant biases in the magnitude, spatial and temporal distributions of OA, and in aerosol hygroscopic properties.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this study, we systematically investigated the effect of the carbon content on the phase structure evolution and macro and nanomechanical properties of the equiatomic CoCrFeNi alloy. A series of ...CoCrFeNi-based high-entropy alloys with 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, and 0.9 wt% carbon were fabricated by vacuum arc melting. The results showed that the alloys retained their single face-center-cubic (FCC) structure with large grains at the carbon contents up to 0.2 wt%. However, in the case of the alloys with carbon contents higher than 0.3 wt%, the single phase structure transformed into the dendrite structure. The inter-dendrite regions of these alloys were eutectic carbides containing lath M7C3 carbides and the FCC phase. The tensile yield strength of the CoCrFeNi alloy increased from 295 to 512 MPa with the addition of 0.9 wt% carbon. The strengthening mechanisms of the alloys were investigated, including the solid solution strengthening due to the interstitial carbon atoms and the precipitation strengthening due to the M7C3 carbides. In addition, the nanoindentation results revealed that the M7C3 carbides showed a high nanohardness of ~17.7 GPa, which is almost four times of that of the FCC phase. We also investigated the elasto-plastic relationships, plastic properties and wear resistance of the FCC phase, while elucidating the eutectic carbide regions and M7C3 carbides. The eutectic carbide regions exhibited brittle fracture, whereas the FCC phase showed plastic fracture.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Magnetic topological phases of quantum matter are an emerging frontier in physics and material science. Along these lines, several kagome magnets have appeared as the most promising platforms. Here, ...we explore magnetic correlations in the kagome magnet Co
Sn
S
. Using muon spin-rotation, we present evidence for competing magnetic orders in the kagome lattice of this compound. Our results show that while the sample exhibits an out-of-plane ferromagnetic ground state, an in-plane antiferromagnetic state appears at temperatures above 90 K, eventually attaining a volume fraction of 80% around 170 K, before reaching a non-magnetic state. Strikingly, the reduction of the anomalous Hall conductivity (AHC) above 90 K linearly follows the disappearance of the volume fraction of the ferromagnetic state. We further show that the competition of these magnetic phases is tunable through applying either an external magnetic field or hydrostatic pressure. Our results taken together suggest the thermal and quantum tuning of Berry curvature induced AHC via external tuning of magnetic order.
Molybdenum disulfide (MoS2) has gained attention because of its high mobility and circular dichroism. As a crucial step to merge these advantages into a single device, we present a method that ...electronically controls and locates p–n junctions in liquid-gated ambipolar MoS2 transistors. A bias-independent p–n junction was formed, and it displayed rectifying I–V characteristics. This p–n diode could perform a crucial role in the development of optoelectronic valleytronic devices.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract
Motivation
Sequence-based protein–protein interaction (PPI) prediction represents a fundamental computational biology problem. To address this problem, extensive research efforts have been ...made to extract predefined features from the sequences. Based on these features, statistical algorithms are learned to classify the PPIs. However, such explicit features are usually costly to extract, and typically have limited coverage on the PPI information.
Results
We present an end-to-end framework, PIPR (Protein–Protein Interaction Prediction Based on Siamese Residual RCNN), for PPI predictions using only the protein sequences. PIPR incorporates a deep residual recurrent convolutional neural network in the Siamese architecture, which leverages both robust local features and contextualized information, which are significant for capturing the mutual influence of proteins sequences. PIPR relieves the data pre-processing efforts that are required by other systems, and generalizes well to different application scenarios. Experimental evaluations show that PIPR outperforms various state-of-the-art systems on the binary PPI prediction problem. Moreover, it shows a promising performance on more challenging problems of interaction type prediction and binding affinity estimation, where existing approaches fall short.
Availability and implementation
The implementation is available at https://github.com/muhaochen/seq_ppi.git.
Supplementary information
Supplementary data are available at Bioinformatics online.
Biocatalysis has become a powerful tool in synthetic chemistry, where enzymes are used to produce highly selective products under mild conditions. Using photocatalytically regenerated cofactors in ...synergistic combination with enzymes in a cascade fashion offers an efficient synthetic route to produce specific compounds. However, the combination of enzymes and photocatalysts has been limited due to the rapid degradation of the biomaterials by photogenerated reactive oxygen species, which denature and deactivate the enzymatic material. Here, we design core–shell structured porous nano-photoreactors for highly stable and recyclable photobiocatalysis under aerobic conditions. The enzymatic cofactor NAD+ from NADH can be efficiently regenerated by the photoactive organosilica core, while photogenerated active oxygen species are trapped and deactivated through the non-photoactive shell, protecting the enzymatic material. The versatility of these photocatalytic core–shell nanoreactors was demonstrated in tandem with two different enzymatic systems, glycerol dehydrogenase and glucose 1-dehydrogenase, where long-term enzyme stability was observed for the core–shell photocatalytic system.
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IJS, KILJ, NUK, PNG, UL, UM
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