9,089 research outputs found

    (S)-Ethyl 2-[4-(6-chloro­quinoxalin-2-yl­oxy)phen­oxy]propanoate

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    In the mol­ecule of the title compound, C19H17ClN2O4, the quinoxaline ring system is planar [maximum deviation = 0.013 (3) Å] and oriented at a dihedral angle of 80.18 (3)° with respect to the benzene ring. In the crystal structure, inter­molecular C—H⋯N inter­actions link mol­ecules into chains. π–π contacts between the quinoxaline systems [centroid–centroid distance = 3.654 (1) Å] may further stabilize the structure

    Design and Synthesis Functional Selective Catalytic Reduction Catalyst for NOx Removal

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    AbstractMeOx-Cu-SSZ-13 (Me=Mn, Ce) was synthesized by physically mixing mental oxide and ion-exchanged zeolite. The composite catalyst showed highly efficient for the NOx removal using NH3-SCR method. And the NO conversion is 98% for MnOx-CeO2/Cu-SSZ-13 at 150°C and 97% for MnOx/Cu-SSZ-13 at 175°C. Meanwhile, the N2 selectivity remains more than 98%. The catalysts are characterized by using XRD and SEM. The XRD patterns show that all samples are highly crystallized and without impurities. The SEM demonstrates all samples have uniform crystal size. Composite catalyst especially combined with Cu-SSZ-13 has considerable potential as a catalyst in the area of NOx conversion

    Refined Equivalent Pinhole Model for Large-scale 3D Reconstruction from Spaceborne CCD Imagery

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    In this study, we present a large-scale earth surface reconstruction pipeline for linear-array charge-coupled device (CCD) satellite imagery. While mainstream satellite image-based reconstruction approaches perform exceptionally well, the rational functional model (RFM) is subject to several limitations. For example, the RFM has no rigorous physical interpretation and differs significantly from the pinhole imaging model; hence, it cannot be directly applied to learning-based 3D reconstruction networks and to more novel reconstruction pipelines in computer vision. Hence, in this study, we introduce a method in which the RFM is equivalent to the pinhole camera model (PCM), meaning that the internal and external parameters of the pinhole camera are used instead of the rational polynomial coefficient parameters. We then derive an error formula for this equivalent pinhole model for the first time, demonstrating the influence of the image size on the accuracy of the reconstruction. In addition, we propose a polynomial image refinement model that minimizes equivalent errors via the least squares method. The experiments were conducted using four image datasets: WHU-TLC, DFC2019, ISPRS-ZY3, and GF7. The results demonstrated that the reconstruction accuracy was proportional to the image size. Our polynomial image refinement model significantly enhanced the accuracy and completeness of the reconstruction, and achieved more significant improvements for larger-scale images.Comment: 24 page

    Highly efficient in vitro adventitious shoot regeneration of Adenosma glutinosum (Linn.) Druce using leaf explants

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    Adenosma glutinosum (Linn.) Druce is an important aromatic plant, but no information is available regarding its regeneration, callus induction and proliferation from leaf explants. In this study, an in vitro shoot regeneration procedure was developed for native A. glutinosum using leaf explants. Callus induction and shoots regeneration from leaf explants was evaluated on Murashige and Skoog (MS) media supplemented with combinations of 6-benzylaminopurine (6-BA) and α-naphthaleneacetic acid (NAA). Callus induction in all 16 treatments exceeded 95%, and the highest adventitious shoot number per callus (7.22 shoots per explant) was obtained when leaf explants were cultured on MS medium supplemented with 0.5 mg• L-1 6-BA, 0.1 mg• L-1 NAA, 3% sucrose and 0.72% agar. The highest shoots strengthening were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.3 mg• L-1 NAA, 3% sucrose, 1.0 g• L-1 active carbon and 0.72% agar. The highest total root number (45.2) and root length (43.3 cm) were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.0 mg• L-1 NAA, 3% sucrose, 1.0 g L−1 active carbon and 0.72% agar, while the highest total root surface area (4.1 cm2) and total root volume (114.1 mm3) were obtained when adventitious buds were cultured on half-strength MS medium supplemented with 0.5 mg• L-1 NAA, 3% sucrose, 1.0 g• L-1 active carbon and 0.72% agar. The efficient plant regeneration system developed here will be helpful for rapid micropropagation and further genetic improvement in A. glutinosum. Keywords: Adenoma glutinous, plant growth regulator, plant regenerationAfrican Journal of Biotechnology Vol. 11(29), pp. 7542-7548, 10 April, 201

    Sea Ice Extraction via Remote Sensed Imagery: Algorithms, Datasets, Applications and Challenges

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    The deep learning, which is a dominating technique in artificial intelligence, has completely changed the image understanding over the past decade. As a consequence, the sea ice extraction (SIE) problem has reached a new era. We present a comprehensive review of four important aspects of SIE, including algorithms, datasets, applications, and the future trends. Our review focuses on researches published from 2016 to the present, with a specific focus on deep learning-based approaches in the last five years. We divided all relegated algorithms into 3 categories, including classical image segmentation approach, machine learning-based approach and deep learning-based methods. We reviewed the accessible ice datasets including SAR-based datasets, the optical-based datasets and others. The applications are presented in 4 aspects including climate research, navigation, geographic information systems (GIS) production and others. It also provides insightful observations and inspiring future research directions.Comment: 24 pages, 6 figure

    Understanding the 0++0^{++} and 2++2^{++} charmonium(-like) states near 3.9 GeV

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    We propose that the X(3915)X(3915) observed in the J/ψ ωJ/\psi\,\omega channel is the same state as the χc2(3930)\chi_{c2}(3930), and the X(3960)X(3960), observed in the Ds+Ds−D_s^+D_s^- channel, is an SS-wave Ds+Ds−D_s^+ D_s^- hadronic molecule. In addition, the JPC=0++J^{PC}=0^{++} {component in the B+→D+D−K+B^+\to D^+D^-K^+} assigned to the X(3915)X(3915) in the current {\it Review of Particle Physics} has the same origin as the X(3960)X(3960), which has a mass around 3.94~GeV. To check the proposal, the available data in the DDˉD\bar D and Ds+Ds−D_s^+ D_s^- channels from both B B decays and γγ\gamma\gamma fusion reaction are analyzed considering both the DDˉD\bar D-DsDˉsD_s\bar D_s-D∗Dˉ∗D^*\bar D^*-Ds∗Dˉs∗D_s^*\bar D_s^* coupled channels with 0++0^{++} and a 2++2^{++} state introduced additionally. It is found that all the data in different processes can be simultaneously well reproduced, and the coupled-channel dynamics produce four hidden-charm scalar molecular states with masses around 3.73, 3.94, 3.99 and 4.23~GeV, respectively. The results may deepen our understanding of the spectrum of charmonia as well as of the interactions between charmed hadrons.Comment: 15 pages, 6 figures, 2 tables, to apear in Sci. Bul

    Cyclin D2 plays a regulatory role in HBV replication

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    AbstractHepatitis B virus (HBV) infection is the leading cause of liver diseases. However, the molecular mechanisms of HBV infection and carcinogenesis have not been fully elucidated. In this study, we found that cyclin D2 was upregualted in HBV-expressing cells and liver tissues of HBV-transgenic mice. Gene silencing of cyclin D2 inhibited HBV DNA replicative intermediates, 3.5kb mRNA, core protein level, as well as the secretions of HBsAg and HBeAg. On the contrary, overexpression of cyclin D2 promoted HBV replication. Furthermore, cyclin D2 regulated HBV replication by enhancing the activity of HBV core and Sp1 promoters by targeting transcription factor CREB2. Silencing of CREB2 abolished enhancement of HBV replication induced by cyclin D2. Together, our study has uncovered a positive role of cyclin D2 in HBV replication. It is conceivable that therapeutic application of cyclin D2 inhibitor in HBV infection therapy

    What Makes for Good Visual Instructions? Synthesizing Complex Visual Reasoning Instructions for Visual Instruction Tuning

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    Visual instruction tuning is an essential approach to improving the zero-shot generalization capability of Multi-modal Large Language Models (MLLMs). A surge of visual instruction datasets with various focuses and characteristics have been proposed recently, enabling MLLMs to achieve surprising results on evaluation benchmarks. To develop more capable MLLMs, in this paper, we aim to investigate a more fundamental question: ``what makes for good visual instructions?''. By conducting a comprehensive empirical study, we find that instructions focused on complex visual reasoning tasks are particularly effective in improving the performance of MLLMs on evaluation benchmarks. Building upon this finding, we design a systematic approach to automatically creating high-quality complex visual reasoning instructions. Our approach employs a synthesis-complication-reformulation paradigm, leveraging multiple stages to gradually increase the complexity of the instructions while guaranteeing quality. Based on this approach, we create the synthetic visual reasoning instruction dataset consisting of 32K examples, namely ComVint, and fine-tune four MLLMs on it. Experimental results demonstrate that our dataset consistently enhances the performance of all the compared MLLMs, e.g., improving the performance of MiniGPT-4 and BLIP-2 on MME-Cognition by 32.6% and 28.8%, respectively. Our code and data are publicly available at the link: https://github.com/RUCAIBox/ComVint.Comment: Work in progres
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