Search

Exploration of low‐dimensional Pb‐free halide perovskites with high stability and outstanding properties is still a pursuing target for developing integrated optoelectronic devices. Herein, comprehensive computational screening of a new class of two‐dimensional (2D) all‐inorganic Pb‐free A3B2X9 perovskites is performed based on the first‐principles calculations. The results indicate that the structural and electronic properties of 2D A3B2X9 structures strongly depend on the B‐X bonding interactions, which makes that their thermodynamic stability follows the trend of A3Bi2X9≈A3Sb2X9>A3In2X9>A3Ga2X9 and their interlayer interactions show a reversal trend. Owing to the lack of lone‐pair electron effect, A3In2X9 indicate direct bandgap characteristics and present the relatively smaller bandgaps and higher electron mobilities than A3Sb2X9 and A3Bi2X9. Benefit from optimal bandgaps (0.8–2.1 eV) and large absorption coefficients (104–105 cm−1) in the visible region, A3B2I9 (B = In, Sb, Bi) exhibit high power conversion efficiency up to 18.2%. Moreover, A3B2I9 (B = Sb, Bi) is verified as efficient photocatalysts for overall water splitting. The theoretical solar‐to‐hydrogen efficiency of Rb3Bi2I9 and Cs3Bi2I9 are >16%. This work suggests huge potential of 2D A3B2X9 perovskites for photovoltaic and photocatalytic applications. [ABSTRACT FROM AUTHOR]

A main challenge for the development of two‐dimensional devices based on atomically thin transition‐metal dichalcogenides (TMDs) is the realization of metal–semiconductor junctions (MSJs) with low contact resistance and high charge transport capability. However, traditional metal–TMD junctions usually suffer from strong Fermi‐level pinning (FLP) and chemical disorder at the interfaces, resulting in weak device performance and high energy consumption. By means of high‐throughput first‐principles calculations, we report an attractive solution via the formation of van der Waals (vdW) contacts between metallic and semiconducting TMDs. We apply a phase‐engineering strategy to create a monolayer TMD database for achieving a wide range of work functions and band gaps, hence offering a large degree of freedom to construct TMD vdW MSJs with desired contact types. The Schottky barrier heights and contact types of 728 MSJs have been identified and they exhibit weak FLP (−0.62 to −0.90) as compared with the traditional metal–TMD junctions. We find that the interfacial interactions of the MSJs bring a delicate competition between the FLP strength and carrier tunneling efficiency, which can be utilized to screen high‐performance MSJs. Based on a set of screening criteria, four potential TMD vdW MSJs (e.g., NiTe2/ZrSe2, NiTe2/PdSe2, HfTe2/PdTe2, TaSe2/MoTe2) with Ohmic contact, weak FLP, and high carrier tunneling probability have been predicted. This work not only provides a fundamental understanding of contact properties of TMD vdW MSJs but also renders their huge potential for electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

The formation of ƞ phase induced by the C‐loss for the laser powder bed fusion (LPBF) of WC–Co cemented carbides largely deteriorates the fracture toughness. The current approach of mixing C additive into powder cannot mitigate the ƞ phase formation. This study proposed a new carbon compensation strategy of coating carbon resource on powder surface by fluidized bed chemical vapor deposition to address this issue. C nanoparticles and carbon nanotubes (CNTs) were selectively deposited on WC–Co powder to make uniform C‐ and CNTs‐coated powders by tuning the deposition temperature. Compared with CNTs‐coated powder and C–WC–Co powder mixtures, the C‐coated powder was more effective in impeding the ƞ phase formation because it had higher reactivity and stronger dissolution ability to compensate the C‐loss in the Co–W–C liquid. However, the single‐carbon compensation was not enough to eliminate the ƞ phase due to the extreme nonequilibrium characteristics of LPBF, which required secondary heat treatment. The conventional heat treatment procedure of 1000°C for 3 h eliminated the ƞ phase for the C‐coated powder but failed for the C–WC–12Co powder mixtures. Because of the absence of ƞ phase, the heat‐treated sample made from C‐coated powder exhibited the highest transverse rupture strength. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate whether fetal echocardiographic parameters were predictive of the postnatal surgical treatment required for fetuses with Tetralogy of Fallot (TOF). Methods: The fetal echocardiographic and postnatal clinical data of all cases of prenatal TOF at Xinhua Hospital from 2016 to 2020 were reviewed. Patients were categorized based on the operation type, and cardiac parameters were compared between groups. Results: Of the 37 fetuses assessed, the development of the pulmonary valve annulus (PVA) was significantly poorer in the transannular patch group. Patients with a prenatal PVA z‐score (Schneider's method) ≥ –2.645, a PVA z‐score (Lee's method) ≥ –2.805, a PVA/aortic valve annulus diameter ratio ≥.697, and a pulmonary annulus index ≥.823 were more likely to undergo pulmonary valve‐sparing surgery. There was a strong correlation between prenatal and postnatal PVA z‐scores. The PVA growth potential was greater in the pulmonary valve‐sparing surgery group. Conclusions: PVA‐related parameters evaluated by fetal echocardiography can predict the type of surgical intervention required and are valuable in improving prenatal counseling in fetal cases of TOF. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) participate in the progression of various cancers. However, the function of circ_0062019 in prostate cancer (PCa) remains unclear. In this study, CCK‐8, colony formation, transwell, tube formation and flow cytometry assays were applied to assess cell proliferation, motility, angiogenesis, cell cycle distribution and apoptosis. The binding association between miR‐1253 and circ_0062019 or NRBP1 was verified through dual‐luciferase reporter assay and RIP assay. Xenograft assay was conducted to evaluate tumour formation in vivo. As a result, circ_0062019 and NRBP1 were increased, but miR‐1253 was decreased in PCa. Depletion of circ_0062019 curbed cell proliferation, migration, invasion, angiogenesis and EMT and induced apoptosis in PCa cells. Circ_0062019 facilitated the malignancy of PCa cells via sequestering miR‐1253. Simultaneously, miR‐1253 hindered PCa cell progression via regulating NRBP1. Ccirc_0062019 silencing suppressed tumour growth in vivo. Taken together, circ_0062019 expedited PCa progression through mediating miR‐1253/NRBP1 pathway. [ABSTRACT FROM AUTHOR]

Several microRNAs are associated with carcinogenesis and tumour progression. Herein, our observations suggest both miR24‐2 and Pim1 are up‐regulated in human liver cancers, and miR24‐2 accelerates growth of liver cancer cells in vitro and in vivo. Mechanistically, miR24‐2 increases the expression of N6‐adenosine‐methyltransferase METTL3 and thereafter promotes the expression of miR6079 via RNA methylation modification. Furthermore, miR6079 targets JMJD2A and then increased the tri‐methylation of histone H3 on the ninth lysine (H3K9me3). Therefore, miR24‐2 inhibits JMJD2A by increasing miR6079 and then increases H3K9me3. Strikingly, miR24‐2 increases the expression of Pim1 dependent on H3K9me3 and METTL3. Notably, our findings suggest that miR24‐2 alters several related genes (pHistone H3, SUZ12, SUV39H1, Nanog, MEKK4, pTyr) and accelerates progression of liver cancer cells through Pim1 activation. In particular, Pim1 is required for the oncogenic action of miR24‐2 in liver cancer. This study elucidates a novel mechanism for miR24‐2 in liver cancer and suggests that miR24‐2 may be used as novel therapeutic targets of liver cancer. [ABSTRACT FROM AUTHOR]

Gas disasters are a major factor influencing safe production in mines: Gas extraction can reduce the gas content in coal seams, providing a guarantee of safer production. The parameters for gas extraction are the primary factors influencing the effectiveness thereof. Aiming at the creep properties of soft coal, a fluid‐solid coupling mathematical model considering creep properties of coal was established based on dynamic evolution equation for permeability considering the effects of matrix shrinkage and effective stress. Additionally, by utilizing COMSOL Multiphysics software, the gas extractions from a single borehole and multiple boreholes were calculated. Moreover, the parameters for gas extraction were optimized and applied and tested in field conditions. The result showed the reduction in gas pressure around the boreholes was larger than that from a single borehole when conducting gas extraction from multiple boreholes. The borehole spacing when extracting gas in coal seams by drilling multiple boreholes should be more than twice that of the effective drainage radius. The optimal borehole spacing ranged from 3.2 to 4.2 m for gas extraction lasting 180 d. Numerical simulation was carried out to ascertain the distribution of stress on coal around a roadway. The result revealed that the damage radius of the roadway was 11.8 m, and a reasonable hole‐sealing depth was 12 m. On condition that the borehole spacing during gas extraction from multiple boreholes was 4 m, the reasonable pre‐extraction time was 180 days taking the gas pressure being reduced to <0.74 MPa as a critical point. Furthermore, the gas content, the amount of extracted gas, etc, in a working face after the parameters for gas extraction were optimized were measured. The result suggested that the effect of gas extraction after optimizing parameters conformed to industry standards. [ABSTRACT FROM AUTHOR]

Destination‐assisted jamming (DAJ) is usually used to protect confidential information against untrusted relays and eavesdroppers in wireless networks. In this paper, a DAJ‐based untrusted relay network with multiple antennas installed is presented. To increase the secrecy, a joint optimization of beamforming and power allocation at the source and destination is studied. A matched‐filter precoder is introduced to maximize the cooperative jamming signal by directing cooperative jamming signals toward untrusted relays. Then, based on generalized singular‐value decomposition (GSVD), a novel transmitted precoder for confidential signals is devised to align the signal into the subspace corresponding to the confidential transmission channel. To decouple the precoder design and optimal power allocation, an iterative algorithm is proposed to jointly optimize the above parameters. Numerical results validate the effectiveness of the proposed scheme. Compared with other schemes, the proposed scheme shows significant improvement in terms of security performance. [ABSTRACT FROM AUTHOR]

Abstract: Background: Chromogenic Epstein‐Barr virus‐encoded RNA (EBER) in situ hybridization (EBER‐ISH) is the gold standard to detect Epstein‐Barr virus (EBV) but it is difficult to use in conjunction with immunohistochemistry (IHC). In this study, our purpose was to validate the sensitivity and specificity of RNAscope in detection of EBV infection in nasal epithelium and its stroma. Methods: Fluorescence‐based RNAscope EBER‐ISH, BRLF1‐ISH, and lineage marker‐IHC were performed on archived formalin‐fixed paraffin‐embedded tissues from normal nasal cavity (n = 5), nasopharynx (n = 8), and nasopharyngeal carcinoma (NPC) specimens (n = 10). Results: The EBERs were detected in 10 of 10 NPC samples but was absent in all normal tissues from the nasal cavity and nasopharynx. The EBERs were exclusively located in pan‐cytokeratin (pan‐CK)‐positive tumor epithelial cells but not in CD45‐positive leukocytes and vimentin‐positive stromal fibroblasts. The level of EBER expression varied in tumor cells within patient and between patients as well. Additionally, 5 of 10 patients had positive BRLF‐ISH. Conclusion: We developed a simple and reproducible method to simultaneously detect mRNA and protein in formalin‐fixed paraffin‐embedded tissues of NPC. As a single staining, traditional EBER continues to be useful; however, for interpretation of the phenotype of EBV‐infected cells, RNAscope is superior. Significantly, we showed that lytic EBV infection took place in NPC tumors. [ABSTRACT FROM AUTHOR]

Abstract: Toll‐like receptor 4 (TLR4) which acts as a receptor for lipopolysaccharide (LPS) has been reported to be involved in carcinogenesis. However, the regulatory mechanism of it has not been elucidated. Herein, we demonstrate that TLR4 promotes the malignant growth of liver cancer stem cells. Mechanistically, TLR4 promotes the expression of histone‐lysine N‐methyltransferase (SUV39 h2) and increases the formation of trimethyl histone H3 lysine 9‐heterochromatin protein 1‐telomere repeat binding factor 2 (H3K9me3‐HP1‐TRF2) complex at the telomeric locus under mediation by long non coding RNA urothelial cancer‐associated 1 (CUDR). At the telomeric locus, this complex promotes binding of POT1, pPOT1, Exo1, pExo1, SNM1B and pSNM1B but prevents binding of CST/AAF to telomere, thus controlling telomere and maintaining telomere length. Furthermore, TLR4 enhances interaction between HP1α and DNA methyltransferase (DNMT3b), which limits RNA polymerase II deposition on the telomeric repeat‐containing RNA (TERRA) promoter region and its elongation, thus inhibiting transcription of TERRA. Ultimately, TLR4 enhances the telomerase activity by reducing the interplay between telomerase reverse transcriptase catalytic subunit (TERT) and TERRA. More importantly, our results reveal that tri‐complexes of HP1 isoforms (α, β and γ) are required for the oncogenic action of TLR4. This study elucidates a novel protection mechanism of TLR4 in liver cancer stem cells and suggests that TLR4 can be used as a novel therapeutic target for liver cancer. [ABSTRACT FROM AUTHOR]

Abstract: Owing to their unique optical, electronic, and catalytic properties, metal nitrides nanostructures are widely used in optoelectronics, clean energy, and catalysis fields. Despite great progress has been achieved, synthesis of defect‐rich (DR) bimetallic nitride nanocrystals or related nanohybrids remains a challenge, and their electrocatalytic application for oxygen evolution reaction (OER) has not been fully studied. Herein, the DR‐Ni3FeN nanocrystals and N‐doped graphene (N‐G) nanohybrids (DR‐Ni3FeN/N‐G) are fabricated through temperature‐programmed annealing and nitridation treatment of NiFe‐layered double hydroxides/graphene oxide precursors by controlling annealing atmosphere. In the nanohybrids, the DR‐Ni3FeN nanocrystals are anchored on N‐G, and mainly show twin crystal defects besides ≈10% of stacking faults. Such nanohybrids can efficiently catalyze OER in alkaline media with a small overpotential (0.25 V) to attain the current density of 10 mA cm−2 and a high turnover frequency (0.46 s−1), superior to their counterparts (the nearly defect‐free Ni3FeN/N‐G), commercial IrO2, and the‐state‐of‐art reported OER catalysts. Except for the superior activity, they show better durability than their counterparts yet. As revealed by microstructural, spectroscopic, and electrochemical analyses, the enhanced OER performance of DR‐Ni3FeN/N‐G nanohybrids originates from the abundant twin crystal defects in Ni3FeN active phase and the strong interplay between DR‐Ni3FeN and N‐G. [ABSTRACT FROM AUTHOR]

Image quality assessment (IQA) research strongly depends upon subjective experiments to provide ground truth to train and evaluate the IQA algorithms. These subjective experiments are cumbersome and expensive. An objective method based on human visual characteristics is proposed to generate the ground truth for distortion images. The proposed metric called Normalised Objective Distortion Score (NODS), using the logarithm of distortion parameter as the image quality score, is easily realised so that much manpower and time cost can be saved. The effectiveness of NODS has been analysed through experiments on five state‐of‐the‐art IQA algorithms, and the result shows that the NODS is stable and can work as well as the subjective score when evaluating the performance of the IQA algorithms. [ABSTRACT FROM AUTHOR]

So far, thymus involution in adults is believed to be irreversible, and endogenous innovation for thymus‐related immunodeficiency remains to be an intractable puzzle. With the expectation of addressing this dilemma, human ovarian surface epithelium (OSE) has been reengineered as epithelial‐mesenchymal transition (EMT)‐tridimensional‐spheroid biologics (ETSB) using a dynamic EMT‐3D‐floating system along with 160 Gy X‐ray‐amelioration, which inoculates subcutaneously into aging rhesus and athymic Balb/cnu/nu mice. Herein, it is bioinformatically validated that ETSB can reset Clock/Arntl‐Per3/Tim molecule rhythm dynamics to re‐prime thymus residual (parathyroid or fatty‐like invalid vesicles yet no thymic architecture) to evolutionary transcription with overall cortex‐medulla endogenized by TECs undergoing MET/EMT reversion. Rhythm dynamics immediately resettles the bHLH‐LTβR‐NFκB‐RelA/B loop as a cascade to provoke the core immune microenvironment for multifunctional innovation of dynamic TCR orchestration, with harmonious naïve T‐subsets and TRECs renewals (P < 0.005). Subsequently, peripheral biological burden and tumor metastasis dynamics are addressed by innovative TCR‐defense/attack dynamics quickly (P < 0.005 vs Control), yet without autoimmune indication to hosts. Moreover, a functional blockade of core‐rhythm dynamics deeply impedes the endogenous innovation of invalid thymus residual. Thus this study may help pioneer a prospective strategy to innovate panoramic central‐peripheral immune microenvironments and defense dynamics for immune‐deficient/aging victims. [ABSTRACT FROM AUTHOR]

The cohesive zone in the blast furnace is largely affected by the softening and melting behaviors of ferrous burden. The Visual High Temperature Method (VHTM) has been employed, in present work, to explore the softening and melting behavior of sinter, two different types of lump ores, and one acid pellet. All iron bearing materials are observed to swell before they shrink. This observation is more dominant in case of dense structured lump ore B. The shrinking temperature intervals are different from one another. This contributes to the gas permeability of ore layer in the cohesive zone because "ore window" is formed. In addition to this, the softening and melting behavior of mixed burdens (consist of sinter and other acid materials) have also been studied. Results display that the softening and melting behavior of all materials are improved. This observation is more dominant for lump ore A. It is attributed to high temperature interactions between sinter and acid iron bearing materials. The high temperature interactivity is largely influenced by the chemical compositions, pore structure, and contact condition. Experimental results of two groups of integrated burdens verify the importance of high temperature interaction for improving the softening and melting characteristics of iron bearing materials. Visual high temperature method is used to study the softening and melting behaviors of single and mixed materials. Results show that softening and melting behaviors are different, which contributes to the gas permeability of ore layer in the cohesive zone. High temperature interaction between sinter and acid materials helps to improve the softening and melting characteristics of burdens. [ABSTRACT FROM AUTHOR]