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User-generated advertising (UGA) is critical to heritage tourism marketing. However, there is a research gap on the impact mechanism of UGA essential elements. Through three scenario experiments, this study explored the matching effects between human elements and review types in UGA of heritage sites and discussed these effects on potential tourists' online interactive behaviours. The findings revealed that (1) graphics with human elements are more effective when paired with subjective experience reviews, while graphics without human elements are better suited for cultural attribute reviews. (2) Matching effects positively influence potential tourists' online interactive behaviours, and psychological distance and awe play mediating roles in this influencing process. Our work provides significant insights for heritage tourism advertising marketing and contributes to the tourism advertising research framework and the marketing competitiveness of heritage sites. [ABSTRACT FROM AUTHOR]

As the concept of environmental, social, and governance (ESG) coincides with the direction of enterprises' sustainable development goals, this study measures sustainable entrepreneurship at the enterprise level by extending ESG measures. A time-varying measure was constructed using state-space models, and the entropy weight method was applied to obtain the final index. We selected annual data of 318 A-share listed companies for 2011–2020 and established a two-way fixed-effects model of time and individuals by applying the constructed sustainable entrepreneurship index. This study examines the impact of sustainable entrepreneurship on corporate value and discusses the moderating effects of financing constraints and government subsidies. The empirical results reveal the following aspects. First, sustainable entrepreneurship has a significant positive effect on corporate value. Second, the greater the degree of financing constraints faced by enterprises, the weaker the role of sustainable entrepreneurship in promoting corporate value. Third, the greater the government subsidies received by enterprises, the stronger the promotion. [ABSTRACT FROM AUTHOR]

Specific Emitter Identification (SEI) is an important method for secure authentication of devices in wireless networks. However, the lack of empirical identification models for many unknown devices further affects the speed and accuracy of their authentication. This work aims to propose an unsupervised open-set domain adaptation (UOSDA) based method to solve the open-set SEI problem with unknown devices appearing in the test set and few shots in the training set. The basic principle is to learn tensor embedding shared feature space and preserving inter-class substructure, which perform feature space mapping under the joint source and target domain led by mapping error minimize in the source domain. Then, in the shared space, the known and unknown targets are divided by the double clusters method of structure prediction and nearest class prototype. Specifically, this Tensor Embedding Substructure Preserving Open Set Domain Adaptation (TESPOSDA) consists of three parts, tensor substructure based invariant feature learning, unsupervised clustering based on known target intra-class structure prediction and neighbor prediction, UOSDA to refine the predicted labels. Finally, experiments are conducted on the real ADS-B dataset to demonstrate the effectiveness of TESPDA. [ABSTRACT FROM AUTHOR]

Constructing single atom catalysts with fine-tuned coordination environments can be a promising strategy to achieve satisfactory catalytic performance. Herein, via a simple calcination temperature-control strategy, CeO2 supported Pt single atom catalysts with precisely controlled coordination environments are successfully fabricated. The joint experimental and theoretical analysis reveals that the Pt single atoms on Pt1/CeO2 prepared at 550 °C (Pt/CeO2-550) are mainly located at the edge sites of CeO2 with a Pt–O coordination number of ca. 5, while those prepared at 800 °C (Pt/CeO2-800) are predominantly located at distorted Ce substitution sites on CeO2 terrace with a Pt–O coordination number of ca. 4. Pt/CeO2-550 and Pt/CeO2-800 with different Pt1-CeO2 coordination environments exhibit a reversal of activity trend in CO oxidation and NH3 oxidation due to their different privileges in reactants activation and H2O desorption, suggesting that the catalytic performance of Pt single atom catalysts in different target reactions can be maximized by optimizing their local coordination structures. CeO2-supported Pt single atoms with different coordination environments exhibit distinct behaviors in reactant adsorption/activation and product desorption, thus showing different catalytic performance for various catalytic oxidation reactions. [ABSTRACT FROM AUTHOR]

The limited capacity of the positive electrode active material in non-aqueous rechargeable lithium-based batteries acts as a stumbling block for developing high-energy storage devices. Although lithium transition metal oxides are high-capacity electrochemical active materials, the structural instability at high cell voltages (e.g., >4.3 V) detrimentally affects the battery performance. Here, to circumvent this issue, we propose a Li1.46Ni0.32Mn1.2O4-x (0 < x < 4) material capable of forming a medium-entropy state spinel phase with partial cation disordering after initial delithiation. Via physicochemical measurements and theoretical calculations, we demonstrate the structural disorder in delithiated Li1.46Ni0.32Mn1.2O4-x, the direct shuttling of Li ions from octahedral sites to the spinel structure and the charge-compensation Mn3+/Mn4+ cationic redox mechanism after the initial delithiation. When tested in a coin cell configuration in combination with a Li metal anode and a LiPF6-based non-aqueous electrolyte, the Li1.46Ni0.32Mn1.2O4-x-based positive electrode enables a discharge capacity of 314.1 mA h g−1 at 100 mA g−1 with an average cell discharge voltage of about 3.2 V at 25 ± 5 °C, which results in a calculated initial specific energy of 999.3 Wh kg−1 (based on mass of positive electrode's active material). Structural instability is a major drawback of high-capacity lithium-based battery cathodes. Here, the authors report a cathode active material with a medium-entropy state created by partial cation disordering capable of restraining the structural evolution in the high-capacity operated spinel phase. [ABSTRACT FROM AUTHOR]

Smaller mesoscale eddies (SMEs) have an important effect on the transmission of ocean temperatures, salinity, energy, and marine biochemical processes. However, traditional altimeters, the dominant sensors used to identify and track eddies, have made it challenging to observe SMEs accurately due to resolution limitations. Eddies drive local upwelling or downwelling, leaving signatures on sea surface temperatures (SSTs) and chlorophyll concentrations (Chls). SST can be observed by spaceborne infrared sensors, and Chl can be measured by ocean color remote sensing. Therefore, multisatellite observations provide an opportunity to obtain information to characterize SMEs. In this paper, an eddy detection algorithm based on SST and Chl images is proposed, which identifies eddies by characterizing the spatial and temporal distribution of SST and Chl data. The algorithm is applied to characterize and analyze SMEs in the Kuroshio Extension. Statistical results on their distribution and seasonal variability are shown, and the formation processes are preliminarily discussed. SMEs generation may be contributed by horizontal strain instability, the interaction of topographic obstacles and currents, and wind stress curl. [ABSTRACT FROM AUTHOR]

Topological domains in ferroelectrics1–5 have received much attention recently owing to their novel functionalities and potential applications6,7 in electronic devices. So far, however, such topological polar structures have been observed only in superlattices grown on oxide substrates, which limits their applications in silicon-based electronics. Here we report the realization of room-temperature skyrmion-like polar nanodomains in lead titanate/strontium titanate bilayers transferred onto silicon. Moreover, an external electric field can reversibly switch these nanodomains into the other type of polar texture, which substantially modifies their resistive behaviours. The polar-configuration-modulated resistance is ascribed to the distinct band bending and charge carrier distribution in the core of the two types of polar texture. The integration of high-density (more than 200 gigabits per square inch) switchable skyrmion-like polar nanodomains on silicon may enable non-volatile memory applications using topological polar structures in oxides.Two types of skyrmion-like polar nanodomain are observed in oxide bilayers transferred onto silicon, and these nanodomains, with distinct resistive behaviour, can be converted to each other under an external electric field. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate GT0918, a 2nd-generation AR antagonist, for its AR down-regulation activity among breast cancer patients. Methods: The effect of GT0918 on AR protein expression was evaluated in AR expression breast cancer cells and in breast cancer xenograft model. A 3 + 3 phase I dose-escalation study was launched in Peking University Cancer Hospital. The endpoints included dose finding, safety, pharmacokinetics, and antitumor activity. Results: GT0918 was demonstrated to effectively suppress the expression of AR protein and the growth of AR-positive breast cancer tumors in mouse xenograft tumor models. All patients treated with GT0918 were at a QD dose-escalation of five dose levels from 100 to 500 mg. The most common treatment-related AEs of any grade were asthenia, anemia, decreased appetite, increased blood cholesterol, increased blood triglycerides, decreased white blood cell count, and increased low-density lipoprotein. Grade 3 AEs were fatigue (2 of 18, 11.1%), aspartate aminotransferase increase (1 of 18, 5.6%), alanine aminotransferase increase (1 of 18, 5.6%), and neutrophil count decrease (1 of 18, 5.6%). Clinical benefit rate (CBR) in 16 weeks was 23.1% (3/13). Among 7 AR-positive patients, 6 can evaluate efficacy, and 2 completed 23.5- and 25-cycle treatment, respectively (as of 2020/1/20). PK parameters showed a fast absorption profile of GT0918 in the single-dose study. GT0918 and its major metabolite reached steady-state serum concentration levels at day 21 after multiple dosing. Conclusion: GT0918 can effectively inhibit AR-positive breast cancer tumor growth. GT0918 was demonstrated well tolerated with a favorable PK profile. The suitable dose of GT0918 was 500 mg QD and may provide clinical benefits for AR-positive mBC. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID-19), a pandemic disease caused by the newly emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused more than 3.8 million deaths to date. Neutralizing antibodies are effective therapeutic measures. However, many naturally occurring mutations at the receptor-binding domain (RBD) have emerged, and some of them can evade existing neutralizing antibodies. Here, we utilized RenMab, a novel mouse carrying the entire human antibody variable region, for neutralizing antibody discovery. We obtained several potent RBD-blocking antibodies and categorized them into four distinct groups by epitope mapping. We determined the involved residues of the epitope of three representative antibodies by cryo-electron microscopy (Cryo-EM) studies. Moreover, we performed neutralizing experiments with 50 variant strains with single or combined mutations and found that the mixing of three epitope-distinct antibodies almost eliminated the mutant escape. Our study provides a sound basis for the rational design of fully human antibody cocktails against SARS-CoV-2 and pre-emergent coronaviral threats. [ABSTRACT FROM AUTHOR]

Thermal management has been considered as a key issue for high-power electronics. Thermal interface materials (TIMs) play an extremely important role in the field of thermal management. Owing to their excellent insulation, mechanical properties and low processing costs, functional polymers have become the popular candidate for preparing TIMs. In order to develop high thermally conductive TIMs, the inorganic fillers with high thermal conductivity are generally composited with polymers. For this purpose, some key technologies are needed to improve the dispersibility of fillers to reduce interfacial thermal resistance and increase thermal conduction channels. This paper reviews recent progresses on effective methods for improving thermal conductivity, which mainly include filler functionalization and processing, filler hybridization and coating, filler orientation and network. After implementing these strategies, the interfacial interaction between fillers and polymers, the synergy effect of different fillers and the thermal conduction pathway inside the matrix can be highly improved, hence enhancing the thermal conductivity of TIMs. [ABSTRACT FROM AUTHOR]

Hyperentanglement purification is a very important element for high-capacity long-distance quantum communication. We present an efficient hyperentanglement purification protocol (hyper-EPP) for nonlocal two-photon systems in three degrees of freedom (DoFs), including the polarization, the time-bin, and the spatial-mode DoFs. Our hyper-EPP is constructed with two steps resorting to polarization–time–spatial parity-check operation using the quantum nondemolition detector and SWAP gates, respectively. With this hyper-EPP, the bit-flip errors in the three DoFs can be corrected with high efficiency. The implementation of our hyper-EPP is contributed by a cross-Kerr nonlinearity between the signal photons and a coherent state via Kerr media, which could be achieved with current techniques. Moreover, some currently available optical elements are applied in the purification process, which offer facilities for the practical implementation. It is useful for long-distance high-capacity quantum communication with hyperentanglement in multiple DoFs. [ABSTRACT FROM AUTHOR]

Air is critical to Ag sintering. The Cu surface of the non-metallized direct-bonding-copper (DBC) substrate can be oxidized seriously for bonding power devices using Ag paste in air. In this paper, we presented a pressureless sintering approach for a multi-scale Ag paste in the formic acid vapor by a commercial vacuum reflowing furnace. The study found that the activation temperature of the formic acid vapor had an obvious effect on the sintering behavior of the multi-scale Ag paste. The multi-scale Ag paste could obtain much denser sintered Ag when the formic acid vapor was rapidly injected at 180 °C by the vacuum reflowing furnace. The sintered Ag necks larger than 0.4 μm and the porosity lower than 11.3% were achieved in formic acid vapor, which had better sintering behavior than Ag nanoparticles (NPs) paste. The thermal resistance of 1200 V/50 A half-bridge IGBT modules by sintering the multi-scale Ag paste in formic acid vapor was 0.41 °C/W, which was ~ 12% lower than those of the commercial IGBT modules using Pb92.5Sn5Ag2.5. This work could overcome the contradiction between the Ag sintering and the Cu oxidation of the non-metallized DBC substrate by the formic acid vapor in a commercial vacuum reflowing furnace. The method is extremely useful for the traditional manufacturer, who do not have to invest any new facilities for the sintering. [ABSTRACT FROM AUTHOR]

Electromigration (EM) behavior induced by current crowding under the condition of multi-physical fields in Cu/Sn3.0Ag0.5Cu/Cu ball grid array (BGA) solder joints was investigated here. First, EM experiments using a specially designed BGA daisy-chain circuit were performed under a current density of 1.43 × 104 A/cm2 at 125 °C for up to 120 h. The experimental results indicated that the polarized growth of intermetallic compounds (IMCs) and void formation occurred in the solder joint. After the 120 h EM testing, the IMC thickness at the anode markedly increased from 5.24 to 32.21 µm, whereas at the cathode it gradually increased from 2.03 to 4.54 µm and subsequently decreased until it completely disappeared. Under the effect of the applied current, voids formed at the current crowding region of the cathode. Second, a finite element model was built to study the void formation considering four driving forces, i.e., the electron wind force, thermal gradient, stress gradient, and atomic concentration gradient. The simulation results showed that the electron wind force played a predominant role in void formation during the EM process, contributing to more than 90% of the total atomic flux. By comparing the experimental results with the simulation results, 0.91 mol/m3 was proposed as the critical atomic concentration of void formation for our specimens in this paper, and the void location was accurately predicted. [ABSTRACT FROM AUTHOR]

Objectives: To systematically explore the effects of overexpressing Hac1p homologues from different sources on protein secretion in Pichia pastoris system.Results: Effects of Hac1p homologues encompassing P. pastoris (PpHac1p), S. cerevisiae (ScHac1p), Trichoderma reesei (TrHac1p) and Homo sapiens (HsXbp1), on secretion of three reporter proteins—β-galactosidase, β-mannanase and glucose oxidase were investigated. No individual Hac1p was optimal for all the enzymes. Rather, by testing a set of Hac1p, the secretory expression of each of the enzymes was improved. Notably, HsXbp1 overexpression improved β-mannanase production from 73 to 108.5 U β-mannanase mL−1 while PpHac1p had no impact in shake flask culture. Moreover, HsXbp1 led to 41 and 67% increases in β-mannanase production in the single- and four-copy strain, respectively in 1-L laboratory fermenter. Transcription analysis of indicative chaperones suggested that HsXbp1 may cause a stronger and prolonged activation of the UPR target chaperone genes.Conclusion: Mammalian HsXbp1 worked better than yeast Hac1p in terms of improving β-mannanase secretion in P. pastoris, and Hac1p screening may offer an effective strategy to engineer the secretion pathway of eukaryotic expression systems. [ABSTRACT FROM AUTHOR]

GaN-based light emitting diodes (LEDs) have been grown by metalorganic chemical vapor deposition on Si(111) substrate with and without 3C-SiC intermediate layer (IL). Structural property has been characterized by means of atomic force microscope, X-ray diffraction, and transmission electron microscope measurements. It has been revealed that a significant improvement in crystalline quality of GaN and superlattice epitaxial layers can be achieved by using 3C-SiC as IL. Regarding of electrical and optical characteristics, it is clearly observed that the LEDs with its IL have a smaller leakage current and higher light output power comparing with the LEDs without IL. The better performance of LEDs using 3C-SiC IL can be contributed to both of the improvements in epitaxial layers quality and light extraction efficiency. As a consequence, in terms of optical property, a double enhancement of the light output power and external quantum efficiency has been realized. [ABSTRACT FROM AUTHOR]

We present a scheme for teleporting a generic two-photon polarization state by using two EPR states as quantum channel based on weak cross-Kerr nonlinearities. As the core component of the present framework, the quantum nondemolition detector based on the weak cross-Kerr nonlinearity acts as an EPR entangler as well as the Bell-state analyzer. This makes the teleportation protocol be achieved near deterministically and be feasible in the current experimental technology. [ABSTRACT FROM AUTHOR]

With the development and adoption of cloud platforms in various fields, malware attacks have become a serious threat to the Internet cloud ecosystem. However, the pooling process of existing graph classification techniques for malware variant detection uses only a serial and single strategy, resulting in localized malicious behaviors of malware that may be overlooked. In this paper, we propose MalDMTP, a malware detection framework based on multilevel graph classification learning, which implements the graph pooling process for malware classification in parallel and performs graph instance-based discrimination. In particular, MalDMTP first constructs an API call graph based on results obtained from dynamic execution of malware. Then it combines multiple graph neural network learning strategies through multi-level pooling to learn the global importance of nodes in the pooled graph and extract node representations from multiple perspectives for heterogeneous graphs. After that, MalDMTP is aggregated into graph representations by the graph-level pooling function GMT based on a multi-head attention mechanism, which goes through a classifier in order to obtain malware prediction labels. Experimental results show that the proposed MalDMTP can achieve 96.53% accuracy on the Alibaba cloud malware dataset, which improves 1.9%   7.6% over the previous single-graph pooling methods on the graph classification task of malware detection. [ABSTRACT FROM AUTHOR]

Background: A mixed feeding strategy (co-feeding of complex carbon sources with methanol) has become a common practice for process development in Pichia pastoris to increase cell biomass and enzyme production levels. However, in some cases mixed feeding did not have a significant impact or even had a negative effect on specific enzyme productivity. We hypothesized that this may be due to a bottleneck in the protein secretion pathway caused by too strong protein expression as a result of mixed feeding operation.Results: Using glucose oxidase (Gox) as a model protein, the individual and synergistic effects of co-feeding of sorbitol or yeast extract (YE) with methanol and Hac1p overexpression on the secretory expression of Gox were investigated both in shake flasks and in a laboratory fermenter. The results showed that YE is superior to sorbitol in terms of stimulating protein expression and cell growth. Moreover, separate applications of the mixed feeding strategy and secretory pathway engineering only achieved limited success in enhancing Gox levels, while the combined use of the two strategies acted synergistically, leading to 297% increase of Gox production and the final enzyme titer reached 787.4 U/mL in GSgox-Pp on 1-L fermenter.Conclusions: Co-feeding of YE combined with secretion pathway engineering significantly improved glucose oxidase secretion, which can be also applied to improve secretory expression of other foreign proteins in P. pastoris system. [ABSTRACT FROM AUTHOR]

We propose a theoretical protocol for preparing four-photon polarization entangled decoherence-free states, which are immune to the collective noise. With the assistance of the cross-Kerr nonlinearities, a two-photon spatial entanglement gate, two controlled-NOT gates, a four-photon polarization entanglement gate are inserted into the circuit, where X homodyne measurements are aptly applied. Combined with some swap gates and simple linear optical elements, four-photon polarization entangled decoherence-free states which can be utilized to represent two logical qubits, |0〉L and |1〉L are achieved at the output ports of the circuit. This generation scheme may be implemented with current experimental techniques. [ABSTRACT FROM AUTHOR]