709 research outputs found

    Endophytic Bacillus subtilis ZZ120 and its potential application in control of replant diseases

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    An endophytic bacterial strain ZZ120 that was isolated from healthy stems of Prunus mume (family: Rosaceae) was identified as Bacillus subtilis based on biochemical and physiological assays and 16s rRNA, rpoB and tetB-yyaO / yyaR genes analysis. Both the culture filtrate and the n-butanol extract of strain ZZ120 showed strong growth inhibition activity in vitro against the replant disease phytopathogens Fusarium graminearum, Alternaria alternata, Rhizoctonia solani, Cryphonectria parasitica and Glomerella glycines. The active metabolite in the filtrate was found to be produced 24 h after inoculation and the concentration remained at a high level until 66 h and was quite thermally stable with more than 75% of the antifungal activity even after being held at 121°C for 30 min. In addition, the antifungal activity of the filtrate remained almost unchanged when the culture was exposed to a pH ranging from 1 to 8, but significantly reduced after the filtrate had been exposed to alkali conditions (pH 9 to 14) for 30 min. The antifungal compounds were isolated from n-butanol extract as a mixture of iturins. The strong antifungal activity suggested that the endophytic B. subtilis ZZ120 and its bioactive components might provide an alternative agent for the biocontrol of replant diseases.Key words: Endophytic bacterium, Bacillus subtilis, replant pathogens

    Hawking Radiation of an Arbitrarily Accelerating Kinnersley Black Hole: Spin-Acceleration Coupling Effect

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    The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated by using a method of the generalized tortoise coordinate transformation. Both the location and temperature of the event horizon depend on the time and on the angles. They coincide with previous results, but the thermal radiation spectrum of massless spinor particles displays a kind of spin-acceleration coupling effect.Comment: 8 pages, no figure, revtex 4.0, revisted version with typesetting errors and misprint correcte

    Cosmological evolution of interacting phantom (quintessence) model in Loop Quantum Gravity

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    The dynamics of interacting dark energy model in loop quantum cosmology (LQC) is studied in this paper. The dark energy has a constant equation of state wxw_x and interacts with dark matter through a form 3cH(ρx+ρm)3cH(\rho_x+\rho_m). We find for quintessence model (wx>1w_x>-1) the cosmological evolution in LQC is the same as that in classical Einstein cosmology; whereas for phantom dark energy (wx<1w_x<-1), although there are the same critical points in LQC and classical Einstein cosmology, loop quantum effect reduces significantly the parameter spacetime (c,wxc, w_x) required by stability. If parameters cc and wxw_x satisfy the conditions that the critical points are existent and stable, the universe will enter an era dominated by dark energy and dark matter with a constant energy ratio between them, and accelerate forever; otherwise it will enter an oscillatory regime. Comparing our results with the observations we find at 1σ1\sigma confidence level the universe will accelerate forever.Comment: 15 pages, 8 figures, to appear in JCA

    Consistent as-similar-as-possible non-isometric surface registration

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    © 2017 The Author(s)Non-isometric surface registration, aiming to align two surfaces with different sizes and details, has been widely used in computer animation industry. Various existing surface registration approaches have been proposed for accurate template fitting; nevertheless, two challenges remain. One is how to avoid the mesh distortion and fold over of surfaces during transformation. The other is how to reduce the amount of landmarks that have to be specified manually. To tackle these challenges simultaneously, we propose a consistent as-similar-as-possible (CASAP) surface registration approach. With a novel defined energy, it not only achieves the consistent discretization for the surfaces to produce accurate result, but also requires a small number of landmarks with little user effort only. Besides, CASAP is constrained as-similar-as-possible so that angles of triangle meshes are preserved and local scales are allowed to change. Extensive experimental results have demonstrated the effectiveness of CASAP in comparison with the state-of-the-art approaches

    Statistical Dependency Guided Contrastive Learning for Multiple Labeling in Prenatal Ultrasound

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    Standard plane recognition plays an important role in prenatal ultrasound (US) screening. Automatically recognizing the standard plane along with the corresponding anatomical structures in US image can not only facilitate US image interpretation but also improve diagnostic efficiency. In this study, we build a novel multi-label learning (MLL) scheme to identify multiple standard planes and corresponding anatomical structures of fetus simultaneously. Our contribution is three-fold. First, we represent the class correlation by word embeddings to capture the fine-grained semantic and latent statistical concurrency. Second, we equip the MLL with a graph convolutional network to explore the inner and outer relationship among categories. Third, we propose a novel cluster relabel-based contrastive learning algorithm to encourage the divergence among ambiguous classes. Extensive validation was performed on our large in-house dataset. Our approach reports the highest accuracy as 90.25% for standard planes labeling, 85.59% for planes and structures labeling and mAP as 94.63%. The proposed MLL scheme provides a novel perspective for standard plane recognition and can be easily extended to other medical image classification tasks
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