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Electrically biased graphene has been studied experimentally as a novel emitter of thermal radiation. However, there is as yet no systematic theory that quantifies the thermal radiation, heat transfer, and electrical properties of electrically biased graphene. To study the thermal transport properties systematically, a heat conduction model is developed and exploited in this paper. The temperature distribution and heat conduction coefficient of graphene under different bias voltages are obtained using our theoretical model. The I–V curve and the relationship between the radiant power and input voltage of graphene are then obtained. This work could help design a novel efficient wavelength-adjustable thermal radiation source. [ABSTRACT FROM AUTHOR]

Various modeling studies have examined the climatic effects of either the Central American Seaway or the Indonesian seaway. The co‐existence of these two tropical seaways may have a greater influence than the existence of a single seaway. Although the dual seaway situation is closer to that reconstructed during Miocene/Pliocene, relevant studies remain scarce. Here, we investigate the co‐effects of dual tropical seaway changes on the Pacific circulation through a set of sensitivity experiments. Our results show that the combined shallow opening of tropical seaways can generate an active Pacific meridional overturning circulation and maintain strong upwelling conditions along the equatorial Pacific, which may have helped favor a "biogenic bloom" during the late Miocene and early Pliocene. Moreover, the logically successive closure of the tropical seaways can provide patterns of zonal sea surface temperature gradients that are similar to those recorded in the equatorial Pacific from the late Miocene to the Pliocene. Plain Language Summary: During the late Miocene and the Pliocene, changes in the Central American and the Indonesian seaways geometry are very important for ocean circulation and global climate. Various modelling studies have examined the separate effects of these two tropical seaways, especially their link to the onset of the Northern Hemisphere ice sheets through changes in the Atlantic meridional overturning circulation and associated heat and moisture transport. Although the existence of dual tropical seaways is closer to the reality, there are very scarce modelling studies exploring the co‐effects of dual tropical seaway changes, especially on the Pacific ocean circulation. Here we provide the results of modelling study on this issue. Our results show that the combined shallow opening of tropical ways can generate an active Pacific meridional overturning circulation (i.e., absent in modern conditions) by which the meridional and zonal sea surface temperature gradient in the Pacific largely reduce. In contrast, a deeper opening of tropical seaways can not produce these changes in the Pacific ocean circulation. This study provides insights into and a better understanding of the role of tropical seaways in shaping the Pacific climate and highlights the importance of the sill depth of each seaway. Key Points: The co‐effects of opening of two tropical seaways on the Pacific circulation are investigated with climate modelShallow opening of tropical seaways can generate an active Pacific meridional overturning circulation, whilst a deeper condition can notThe stepwise closure of the tropical seaways can provide similar‐to‐record patterns of zonal sea surface temperature gradients [ABSTRACT FROM AUTHOR]

We present an X-ray spectrum of the diffuse X-ray background (DXRB) between 1.5 and 120 keV, as measured with the Low-Energy Detector (LE) and the High-Energy Detector (HE) aboard the Insight-HXMT satellite, based on 'blank-sky' observations. LE covers a nominal energy range of 1–15 keV and HE 20–250 keV, but calibration issues and data quality narrowed the energy range for this work. The LE background was directly measured with 'blind' detector modules, while the HE background was derived from Earth-occultation data. With the LE data alone, the measured DXRB spectrum can be well-described by a power law; fitting the LE and HE data jointly, however, a spectral cut-off must be introduced in the model to account for the measurements above 30 keV. Modelling the combined spectrum with a cut-off power law, the best-fitting photon index is 1.40, normalization 9.57  |$\rm ph~cm^{-2}\,s^{-1}\,keV^{-1}\,sr^{-1}$| (at 1 keV), and cut-off energy 55 keV after correcting for the effects of the Earth albedo and atmospheric emission (which are significant in the HE band). Based on the best-fitting cut-off power law, we derived the spectral energy distribution (SED) of the DXRB. The shape of the SED is in general agreement with the published measurements, but the overall normalization is lower by varying amounts, except for the HEAO-1 result, with which our result is in good agreement. [ABSTRACT FROM AUTHOR]

In this paper, we presented a detailed timing analysis of a prominent outburst of 4U 0115+63 detected by Insight -HXMT in 2017 August. The spin period of the neutron star was determined to be 3.613 98 ± 0.000 02 s at MJD 57978. We measured the period variability and extract the orbital elements of the binary system. The angle of periastron evolved with a rate of |$0.048^\circ \pm 0.003^\circ \rm \, yr^{-1}$|⁠. The light curves are folded to sketch the pulse profiles in different energy ranges. A multipeak structure in 1–10 keV is clearly illustrated. We introduced wavelet analysis into our data analysis procedures to study quasi-periodic oscillation (QPO) signals and perform a detailed wavelet analysis in many different energy ranges. Through the wavelet spectra, we report the discovery of a QPO at the frequency of ∼10 mHz. In addition, the X-ray light curves showed multiple QPOs in the period of ∼16–32 and ∼67–200 s. We found that the ∼100 s QPO was significant in most of the observations and energies. There exist positive relations between X-ray luminosity and their Q-factors and S-factors, while the QPO periods have no correlation with X-ray luminosity. In wavelet phase maps, we found that the pulse phase of ∼67–200 s QPO is drifting frequently while that of ∼16–32 s QPO is scarcely drifting. The dissipation of oscillations from high energy to low energy was also observed. These features of QPOs in 4U 0115+63 provide a new challenge to our understanding of their physical origins. [ABSTRACT FROM AUTHOR]

We theoretically demonstrate a polarizer with an electrically controllable polarizing direction in the far infrared range using two orthogonal periodic arrays of graphene ribbons, which have different widths and are supported on a dielectric film placed on a thick piece of metal. The operation mechanism originates from the polarization-dependent resonant absorption of the two orthogonal graphene ribbons, which can be respectively controlled with different external bias voltages. The operation wavelength can be expanded to terahertz (THz) radiation. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Dysregulated lipid metabolism has been reported in the progression of hepatocellular carcinoma (HCC). In the present study, we investigated the molecular characteristics of lipid-metabolism-related genes (IMRGs) as prognostic markers for HCC. MATERIALS AND METHODS: Multi-dimensional bioinformatics analyses were performed to comprehensively analyze IMRGs, and to construct prognostic prediction signatures. RESULTS: Data of 770 HCC patients and their corresponding 776 IMRGs were downloaded from three databases. Patients were classified into 2 molecular clusters that were associated with overall survival, clinical characteristics, and immune cells. The biological functions of the IMRGs differentially expressed between the 2 clusters were associated with tumor-related metabolic pathways. A 6 IMRG signature (6-IS), consisting of FMO3, SLC11A1, RNF10, KCNH2, ME1, and ZIC2, was established as an independent prognostic factor for HCC. The performance of the signature of 6-IS prognostic was verified in a validation set and compared to an external data set. It was revealed that the 6-IS could effectively predict the prognosis of patients with HCC. CONCLUSIONS: This study provides new insights into the role of IMRGs in the pathogenesis of HCC, and presents a novel signature (6-IS) to predict the prognosis of HCC. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Currently, detection of SARS-CoV-2 RNA is standard in the diagnosis of COVID-19 (2019-nCoV). However, reliable and rapid serological diagnostic methods to screen SARS-CoV-2 infected patients, including those who do not have overt symptoms, are urgently needed. Most studies have described serological tests based on the detection of SARS-CoV-2- specific IgM and IgG. Here, we attempted to systematically analyze the positive rates and comprehensive diagnostic efficacy of IgM and IgG in response to SARS-CoV-2 infection. MATERIALS AND METHODS: By systematically searching PubMed, medRxiv, bioRxiv and other databases, studies regarding the detection of peripheral blood IgM and/or IgG related to SARS-CoV-2 were collected. The positive rate, sensitivity (SEN), specificity (SPE), area under the curve (AUC) and corresponding 95% CIs were obtained by weighted quantitative mergence, and the source of heterogeneity was explored by performing a subgroup study and sensitivity analysis. RESULTS: A total of 30 studies were included, which were comprised of 3856 confirmed SARS-CoV-2 RNA positive cases, 368 suspected RNA negative cases, 1167 asymptomatic carriers, and 2526 RNA negative controls. The corresponding meta-analysis showed that in confirmed cases with 2019-nCoV, the positive rates of single IgM, single IgG and their joint detection related to SARS-CoV-2 were 61.2% (95% CI: 53.4%-69.0%), 58.8% (95% CI: 49.6%-68.0%) and 62.1% (52.7%-71.4%), respectively. In suspected RNA negative cases, the positive rates of single IgM, single IgG and their joint detection were 29.0% (95% CI: 14.0%-44.0%), 37.0% (95% CI: 20.0%-55.0%) and 55.0% (95% CI: 19.0%-90.0%), respectively. Interestingly, IgM/IgG detection also demonstrated a positive rate of 19% (95% CI: 10.0%-27.0%) in asymptomatic cases. Using RTPCR test as reference, the AUCs of IgM, IgG and IgM/IgG in the diagnosis of 2019-nCoV infection were 0.9656, 0.9766, and 0.9838, respectively. The stratified analyses showed that among confirmed cases with 2019-nCoV, the positive rates of IgM and IgG were 27.3% (95%CI: 19.8%-34.8%) and 22.3% (95% CI: 11.3%-33.3%), respectively, 0-7days following the onset of symptoms, whereas the positive rate of parallel IgM/IgG testing attained 39.3% (95% CI: 24.2%-54.4%). Moreover, the efficacy of antibody testing based on CLIA (chemiluminescence enzyme immunoassays) in diagnosing 2019-nCoV infection was higher than that of LFIA (lateral flow immunoassays) and ELISA (enzyme linked immunosorbent assay). CONCLUSIONS: IgM, IgG and their joint testing exhibited high clinical value in the diagnosis of 2019-nCoV, which may assist in making up for the deficiency of throat swab RNA tests. [ABSTRACT FROM AUTHOR]

Presents a novel semiconductor quantum well (QW) structure consisting of alternating (In,Ga)As and Ga(P,As,Sb0 layers grown pseudomorphically on a GaAs substrate by all-solid-source molecular beam epitaxy. Determination of the band gap of the QW by the thickness and composition of both types of layers; Explanation for the strong room-temperature photoluminescence.

INTRODUCTION: Wilms' tumor (WT) is the most common childhood tumor, and recent studies have demonstrated that abnormal expression of microRNA (miRNA) plays an important role in the progression of WT. However, the effect of miR-572 on cell metastasis and epithelial-mesenchymal transition (EMT) in WT is unclear. PATIENTS AND METHODS: The alternation of miR-572 and cadherin 1 (CDH1) expression was assessed by quantitative Real-time polymerase chain reaction (qRT-PCR). Transwell assay was performed to explore the effects of miR-572 and CDH1 on the metastasis of WT cells. The EMT markers and CDH1 expressions were detected by Western blot. The relationship between miR-572 and CDH1 was verified by dual-luciferase reporter assay. RESULTS: Upregulation of miR-572 was identified in WT tissues. Increased miR-572 promoted cell metastasis and EMT progress in WT. Moreover, miR-572 directly targeted CDH1 and negatively regulated CDH1 expression in WT tissues. The knockdown of CDH1 showed a promoting effect on cell metastasis and EMT, while overexpression of CDH1 significantly weakened the effect of miR-572. CONCLUSIONS: MiR-572 targeted CDH1 to promote cell metastasis in WT by suppressing EMT. [ABSTRACT FROM AUTHOR]

Many state-of-the-art image matching methods, based on the feature matching, have been widely studied in the remote sensing field. These methods of feature matching which get highly operating efficiency, have a disadvantage of low accuracy and robustness. This paper proposes an improved image matching method which based on the SURF algorithm. The proposed method introduces color invariant transformation, information entropy theory and a series of constraint conditions to increase feature points detection and matching accuracy. First, the model of color invariant transformation is introduced for two matching images aiming at obtaining more color information during the matching process and information entropy theory is used to obtain the most information of two matching images. Then SURF algorithm is applied to detect and describe points from the images. Finally, constraint conditions which including Delaunay triangulation construction, similarity function and projective invariant are employed to eliminate the mismatches so as to improve matching precision. The proposed method has been validated on the remote sensing images and the result benefits from its high precision and robustness. [ABSTRACT FROM AUTHOR]

The influence of two types of sizings (3#, 4#) on the surface of carbon fibres, and interface of carbon fibre composites were investigated. It was found that the surface topography of carbon fibres studied appeared to consist of grooves along the fibre axial direction. Sizing decreased the roughness of fibres surface, and the surface roughness value (Ra) for the 3# sized fibre was higher than that of the 4# sized fibre. X-ray photoelectron spectroscopy (XPS) result shows that the percentages of functional group -C-OH or -C-OR on the 4# sized fibre was less than that of 3# sized fibre, but the percentages of functional group containing oxygen -C = O on the 4# sized fibre was more than that of 3# sized fibre. The 4# sizing can improve the soakage of LY-1 epoxy resin to carbon fibre when compared to the 3# sizing. In addition, the IFSS of 4# sized fibre/LY-1 epoxy resin monofilament composite was 44·66 MPa, presenting 120% higher than 3# sized fibre. Therefore, 4# sized fibre has a stronger bond with the resin matrix compared with 3# sizing fibre. [ABSTRACT FROM AUTHOR]

The aerobic oxidation of p-toluic acid to terephthalic acid over tetra( p-chlorophenylporphinato)manganese (T( p-Cl)PPMnCl)/cobalt acetate was reported for the first time. The co-catalysis of T( p-Cl)PPMnCl/Co(OAc)2 was also studied. The studies indicated that the PTA oxidation was influenced by the catalyst composition, catalyst concentrations and reaction conditions. A preliminary mechanism of this co-catalyzed oxidation reaction was proposed based on experimental observations. The aerobic oxidation of PTA to TPA over T( p-Cl)PPMnCl/Co(OAc)2 was reported for the first time, and the co-catalysis of T( p-Cl)PPMnCl/Co(OAc)2 for aerobic oxidation of PTA to TPA was also studied. A preliminary mechanism for the PTA oxidation over T( p-Cl)PPMnCl/Co(OAc)2 was proposed based on the experiment results.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]