34 research outputs found
NPR3 and NPR4 are receptors for the immune signal salicylic acid in plants
Salicylic acid (SA) is a plant immune signal produced upon pathogen challenge to induce systemic acquired resistance (SAR). It is the only major plant hormone for which the receptor has not been firmly identified. SAR in Arabidopsis requires the transcription cofactor NPR1 (nonexpresser of PR genes 1), whose degradation serves as a molecular switch for SAR. Here we show that NPR1 paralogues, NPR3 and NPR4, are SA receptors that bind SA with different affinities and function as adaptors of the Cullin 3 ubiquitin E3 ligase to mediate NPR1 degradation in an SA-regulated manner. Accordingly, the npr3 npr4 mutant accumulates higher levels of NPR1 and is insensitive to SAR induction. Moreover, this mutant is defective in pathogen effector-triggered programmed cell death and immunity. Our study reveals the mechanism of SA perception in determining cell death and survival in response to pathogen challenge
A combination of convolutional and graph neural networks for regularized road surface extraction
Road surface extraction from high-resolution remote sensing images has many engineering applications; however, extracting regularized and smooth road surface maps that reach the human delineation level is a very challenging task, and substantial and time-consuming manual work is usually unavoidable. In this article, to solve this problem, we propose a novel regularized road surface extraction framework by introducing a graph neural network (GNN) for processing the road graph that is preconstructed from the easily accessible road centerlines. The proposed framework formulates the road surface extraction problem as two-sided width inference of the road graph and consists of a convolutional neural network (CNN)-based feature extractor and a GNN model for vertex attribute adjustment. The CNN extracts the high-level abstract features of each vertex in the graph as the input of the GNN and also the road boundary features that allow us to distinguish roads from the background. The GNN propagates and aggregates the features of the vertices in the graph to achieve global optimization of the regression of the regularized widths of the vertices. At the same time, a biased centerline map can also be corrected based on the width prediction result. To the best of the authors’ knowledge, this is the first study to have introduced a GNN to regularized human-level road surface extraction. The proposed method was evaluated on four diverse datasets, and the results show that the proposed method comprehensively outperforms the recent CNN-based segmentation methods and other regularization methods in the intersection over union (IoU) and smoothness score, and a visual check shows that a majority of the prediction results of the proposed method approach the human delineation level
Dry Permanent Magnetic Separator: Present Status and Future Prospects
Dry permanent magnetic separators have been widely used in the mineral and coal processing industries due to their simple operation and high separation efficiency. These tools not only discard some amount of bulk gangue from the raw ore, thereby reducing the volume of the grinding operation and cutting energy consumption, but also do not require water in the sorting process, thereby expanding their applicability to arid and cold areas. With the depletion of global iron ore resources, a dry, low-cost processing or pre-sorting prior to the wet separation has received the attention of industrial practitioners as a potential alternative. The performance of dry magnetic separators plays a critical role in dry processing This paper reviews the dry magnetic separators available in the literature and describes their operating principles, separation performance, and applications. A detailed comparison of different separators is also conducted to evaluate the differences in their sorting performance and mechanisms and to provide a reference for the optimization of dry magnetic separators
Barriers to prophylactic treatment among patients with haemophilia A in Shandong Province, China: a qualitative study
Abstract Background Haemophilia A is a rare, hereditary haemorrhagic disease that manifests as induced spontaneous bleeding and leads to disability or premature death in severe cases. Prophylactic treatment is optimal for patients to prevent uncontrolled bleeding and reduce the severity of the injury. However, little is known about the use of prophylactic treatment among patients with haemophilia A in China, especially barriers that predispose them to low or non-adherence. In this study, we explore the barriers to the prophylactic treatment of patients with haemophilia A. Method We used personal interviews and focus groups to collect the data and analysed the data through thematic analysis. Purposive sampling was employed to recruit our participants. We continued recruiting participants until data saturation was reached from the thematic analysis. Ultimately, we obtained 37 participants, among whom 19 participated in personal interviews and 18 participated in focus groups (i.e., 3 focus groups with 6 participants each). Results Three themes and nine subthemes were identified from the thematic analysis. Nine subthemes (i.e., perceived barriers) emerged from the analysis, which were further clustered into three themes: (1) poor primary health care, (2) inadequate financial support, and (3) a lack of patient-centred care. Conclusion The findings presented in this descriptive qualitative study offer a unique view of Chinese patients with haemophilia A and their barriers to prophylactic treatment. Our findings not only provide an in-depth understanding of barriers to prophylactic treatment encountered by Chinese patients with haemophilia A but also address the urgent need to strengthen primary care, provide adequate financial support, and establish patient-centred care for these suffering patients
Experimental Study on the Localized Deformation and Damage Behavior of Polymer-Bonded Explosive Simulant under Cyclic Compression
Uniaxial cyclic compression tests were performed to investigate the compression deformation and damage of polymer-bonded explosive (PBX) simulant, particularly shear localization. The macroscopic mechanical behavior and mesoscale failure mechanisms of the PBX simulant were analyzed by optical observation and SEM scanning methods. After each cyclic compression, the specimen was scanned by X-ray computed tomography (CT), and the internal 3D deformation of the specimen was calculated using the digital volume correlation (DVC) method. The results show that the stress–strain curve of the PBX simulant exhibits five stages and coincides with the morphological changes on the surface of the specimen. The mesoscale failure mechanism is dominated by particle interface debonding and binder tearing, accompanied by a small amount of particle breakage. There are three bifurcation points (T1, T2, and T3) in the curves of the normal and shear strain components with compression strain. It was found that these bifurcation points can reflect the full progression of the specimen from inconspicuous damage to uniformly distributed damage, shear localization, and eventual macroscopic fracture. The strain invariant I1 can quantitatively and completely characterize the deformation and damage processes of the PBX simulant under cyclic compression
Molecular phylogeny and divergence time estimates using the mitochondrial genome for the hadal snailfish from the Mariana trench
Negative regulator of E2F transcription factors links cell cycle checkpoint and DNA damage repair
Protein kinase ATR inhibits E3 ubiquitin ligase CRL4PRL1 to stabilize ribonucleotide reductase in response to replication stress
Summary: The protein kinase ATR is essential for replication stress responses in all eukaryotes. Ribonucleotide reductase (RNR) catalyzes the formation of deoxyribonucleotide (dNTP), the universal building block for DNA replication and repair. However, the relationship between ATR and RNR is not well understood. Here, we show that ATR promotes the protein stability of RNR in Arabidopsis. Through an activation tagging-based genetic screen, we found that overexpression of TSO2, a small subunit of RNR, partially suppresses the hypersensitivity of the atr mutant to replication stress. Biochemically, TSO2 interacts with PRL1, a central subunit of the Cullin4-based E3 ubiquitin ligase CRL4PRL1, which polyubiquitinates TSO2 and promotes its degradation. ATR inhibits CRL4PRL1 to attenuate TSO2 degradation. Our work provides an important insight into the replication stress responses and a post-translational regulatory mechanism for RNR. Given the evolutionary conservation of the proteins involved, the ATR-PRL1-RNR module may act across eukaryotes
DNA barcoding the ichthyofauna of the Yangtze River: insights from the molecular inventory of a mega-diverse temperate fauna
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