24 research outputs found

    Crossing at a Red Light: Behavior of Cyclists at Urban Intersections

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    To investigate the relationship between cyclist violation and waiting duration, the red-light running behavior of nonmotorized vehicles is examined at signalized intersections. Violation waiting duration is collected by video cameras and it is assigned as censored and uncensored data to distinguish between normal crossing and red-light running. A proportional hazard-based duration model is introduced, and variables revealing personal characteristics and traffic conditions are used to describe the effects of internal and external factors. Empirical results show that the red-light running behavior of cyclist is time dependent. Cyclist’s violating behavior represents positive duration dependence, that the longer the waiting time elapsed, the more likely cyclists would end the wait soon. About 32% of cyclists are at high risk of violation and low waiting time to cross the intersections. About 15% of all the cyclists are generally nonrisk takers who can obey the traffic rules after waiting for 95 seconds. The human factors and external environment play an important role in cyclists’ violation behavior. Minimizing the effects of unfavorable condition in traffic planning and designing may be an effective measure to enhance traffic safety

    Capsaicin Protects Mice from Community-Associated Methicillin-Resistant Staphylococcus aureus Pneumonia

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    BACKGROUND: α-toxin is one of the major virulence factors secreted by most Staphylococcus aureus strains, which played a central role in the pathogenesis of S. aureus pneumonia. The aim of this study was to investigate the impact of capsaicin on the production of α-toxin by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strain USA 300 and to further assess its performance in the treatment of CA-MRSA pneumonia in a mouse model. METHODOLOGY/PRINCIPAL FINDINGS: The in vitro effects of capsaicin on α-toxin production by S. aureus USA 300 were determined using hemolysis, western blot, and real-time RT-PCR assays. The influence of capsaicin on the α-toxin-mediated injury of human alveolar epithelial cells was determined using viability and cytotoxicity assays. Mice were infected intranasally with S. aureus USA300; the in vivo protective effects of capsaicin against S. aureus pneumonia were assessed by monitoring the mortality, histopathological changes and cytokine levels. Low concentrations of capsaicin substantially decreased the production of α-toxin by S. aureus USA 300 without affecting the bacterial viability. The addition of capsaicin prevented α-toxin-mediated human alveolar cell (A549) injury in co-culture with S. aureus. Furthermore, the in vivo experiments indicated that capsaicin protected mice from CA-MRSA pneumonia caused by strain USA 300. CONCLUSIONS/SIGNIFICANCE: Capsaicin inhibits the production of α-toxin by CA-MRSA strain USA 300 in vitro and protects mice from CA-MRSA pneumonia in vivo. However, the results need further confirmation with other CA-MRSA lineages. This study supports the views of anti-virulence as a new antibacterial approach for chemotherapy

    Cyanobacteria bloom prevention and control and salvage disposal integrated management system

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    Cyanobacteria are large single-cell prokaryotes that can undergo oxygen-producing photosynthesis. However, if the cyanobacteria are contaminated by nitrogen, phosphorus and other elements, cyanobacteria will cause the phenomenon of “water bloom” in the lake, which will seriously endanger the safety of humans, animals, fish and shrimps. To help lake management units to prevent and control the outbreak of cyanobacteria, this paper designed and developed a comprehensive management system for the prevention and control of cyanobacteria blooms and salvage treatment. The system consists of four subsystems: the operational reporting subsystem, the monitoring data management system, the algae environmental protection disposal process management system, and the real-time cyanobacteria monitoring system. The three-dimensional interaction between the WEB end and the mobile patrol handheld terminal makes the system more efficient and convenient. The neighborhood image is denoised by the neighborhood averaging method, and the K-means algorithm is used for clustering training, which makes the classification of the algae pictures taken. The realization of the system effectively prevented the large-scale outbreak of cyanobacteria, providing a new idea for monitoring and processing cyanobacteria blooms

    Design and Implementation of Visualization System for Wastewater Treatment in Dianchi Lake Based on WebGIS

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    Based on the current state’s emphasis on environmental governance, combined with a series of pollution problems faced by Dianchi Lake, traditional environmental governance methods do not have real-time effective information analysis and processing capabilities. Therefore, the construction of an information visualization system that meets Dianchi wastewater treatment is currently the general trend of environmental construction.In this paper, the (B/S) model system architecture is used to establish a WebGIS-based Dianchi basin wastewater treatment visualization system, which greatly improves the system’s interaction and development costs.The system database adopts the spatial database model of GeoDatabase, which well solves the correlation between spatial data and attribute data, and can display and analyze corresponding data according to the data format and attributes.It provides an accurate and efficient visualization platform system for Dianchi pollution treatment. The commissioning of this system has greatly improved the governance efficiency of the relevant management departments of Dianchi Lake, and provided reliable data support for the dynamic adjustment of the department’s governance strategy

    Approaching the Dimerization Mechanism of Small Molecule Inhibitors Targeting PD-L1 with Molecular Simulation

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    Inhibitors blocking the PD-1/PD-L1 immune checkpoint demonstrate impressive anti-tumor immunity, and small molecule inhibitors disclosed by the Bristol-Myers Squibb (BMS) company have become a hot topic. In this work, by modifying the carbonyl group of BMS-202 into a hydroxyl group to achieve two enantiomers (MS and MR) with a chiral center, we found that this is an effective way to regulate its hydrophobicity and thus to reduce the negative effect of polar solvation free energy, which enhances the stability of PD-L1 dimer/inhibitor complexes. Moreover, we studied the binding modes of BMS-200 and BMS-202-related small molecule inhibitors by molecular dynamics simulation to explore their inhibitory mechanism targeting PD-L1 dimerization. The results showed that the size exclusion effect of the inhibitors triggered the rearrangement of the residue ATyr56, leading to the formation of an axisymmetric tunnel-shaped pocket, which is an important structural basis for improving the binding affinity of symmetric inhibitors with PD-L1. Furthermore, after inhibitor dissociation, the conformation of ATyr123 and BMet115 rearranged, which blocked the entrance of the binding pocket, while the reverse rearrangements of the same residues occurred when the PD-L1 monomer was complexed with the inhibitors, preparing PD-L1 for dimerization. Overall, this study casts a new light on the inhibitory mechanism of BMS inhibitors targeting PD-L1 dimerization and provides an idea for designing novel small molecule inhibitors for future cancer immunotherapy

    Design and implementation of a general batch simulation tool of SOWFA and its application in training a single-turbine surrogate

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    Simulator fOr Wind Farm Applications (SOWFA) is a powerful wind farm simulation tool. It is widely used in wake effect research. However, the integration between AI and SOWFA is weak. Without AI, it is difficult for us to fully use SOWFA. The installation, parameter settings, and calculation procedures of SOWFA are complex, which hinders the application of SOWFA in practical power system engineering scenarios. To mitigate these issues, a batch simulation tool of SOWFA based on Docker and Python is designed and implemented. Firstly, the Docker engine is used to realize the virtualization container management of SOWFA. A SOWFA installation image is built to make it easy to migrate and deploy. Secondly, a Python application programming interface (API) of the SOWFA container is programmed to realize parameter editing, calculation process management, and batch simulations. Finally, a batch simulation post-processing Python API is constructed based on the ParaView library so that the SOWFA batch simulation results can be collated into data samples for downstream tasks. The above SOWFA image and Python API are tested in a simple single-turbine wake analysis scenario. With the samples generated by the batch simulations, an autoencoder-based single-turbine wake prediction surrogate model is trained, which verifies the effectiveness of the SOWFA batch simulation tool designed in this paper

    Is the Triggering of PD-L1 Dimerization a Potential Mechanism for Food-Derived Small Molecules in Cancer Immunotherapy? A Study by Molecular Dynamics

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    Using small molecules to inhibit the PD-1/PD-L1 pathway is an important approach in cancer immunotherapy. Natural compounds such as capsaicin, zucapsaicin, 6-gingerol and curcumin have been proposed to have anticancer immunologic functions by downregulating the PD-L1 expression. PD-L1 dimerization promoted by small molecules was recently reported to be a potential mechanism to inhibit the PD-1/PD-L1 pathway. To clarify the molecular mechanism of such compounds on PD-L1 dimerization, molecular docking and molecular dynamics simulations were performed. The results evidenced that these compounds could inhibit PD-1/PD-L1 interactions by directly targeting PD-L1 dimerization. Binding free energy calculations showed that capsaicin, zucapsaicin, 6-gingerol and curcumin have strong binding ability with the PD-L1 dimer, where the affinities of them follow the trend of zucapsaicin > capsaicin > 6-gingerol ≈ curcumin. Analysis by residue energy decomposition, contact numbers and nonbonded interactions revealed that these compounds have a tight interaction with the C-sheet, F-sheet and G-sheet fragments of the PD-L1 dimer, which were also involved in the interactions with PD-1. Moreover, non-polar interactions between these compounds and the key residues Ile54, Tyr56, Met115 and Ala121 play a key role in stabilizing the protein–ligand complexes in solution, in which the 4′-hydroxy-3′-methoxyphenyl group and the carbonyl group of zucapsaicin, capsaicin, 6-ginger and curcumin were significant for the complexation of small molecules with the PD-L1 dimer. The conformational variations of these complexes were further analyzed by free energy landscape (FEL) and principal component analysis (PCA) and showed that these small molecules could make the structure of dimers more stable. This work provides a mechanism insight for food-derived small molecules blocking the PD-1/PD-L1 pathway via directly targeting the PD-L1 dimerization and offers theoretical guidance to discover more effective small molecular drugs in cancer immunotherapy

    Complete Chloroplast Genome Sequence and Phylogenetic Analysis of Aster tataricus

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    We sequenced and analyzed the complete chloroplast genome of Aster tataricus (family Asteraceae), a Chinese herb used medicinally to relieve coughs and reduce sputum. The A. tataricus chloroplast genome was 152,992 bp in size, and harbored a pair of inverted repeat regions (IRa and IRb, each 24,850 bp) divided into a large single-copy (LSC, 84,698 bp) and a small single-copy (SSC, 18,250 bp) region. Our annotation revealed that the A. tataricus chloroplast genome contained 115 genes, including 81 protein-coding genes, 4 ribosomal RNA genes, and 30 transfer RNA genes. In addition, 70 simple sequence repeats (SSRs) were detected in the A. tataricus chloroplast genome, including mononucleotides (36), dinucleotides (1), trinucleotides (23), tetranucleotides (1), pentanucleotides (8), and hexanucleotides (1). Comparative chloroplast genome analysis of three Aster species indicated that a higher similarity was preserved in the IR regions than in the LSC and SSC regions, and that the differences in the degree of preservation were slighter between A. tataricus and A. altaicus than between A. tataricus and A. spathulifolius. Phylogenetic analysis revealed that A. tataricus was more closely related to A. altaicus than to A. spathulifolius. Our findings offer valuable information for future research on Aster species identification and selective breeding
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