39 research outputs found
Lysine residues of interferon regulatory factor 7 affect the replication and transcription activatormediated lytic replication of Kaposi’s sarcomaassociated herpesvirus/human herpesvirus 8
Kaposi’s sarcoma-associated herpesvirus (KSHV) infection goes through latent and lytic phases, which are controlled by the viral replication and transcription activator (RTA). Upon KSHV infection, the host responds by suppressing RTA-activated lytic gene expression through interferon regulatory factor 7 (IRF-7), a key regulator of host innate immune response. Lysine residues are potential sites for post-translational modification of IRF-7, and were suggested to be critical for its activity. In this study, we analysed the 15 lysine residues for their effects on IRF-7 function by site-directed mutagenesis. We found that some mutations affect the ability of IRF-7 to activate interferon (IFN)-a1 and IFN-b promoters, to suppress RTA-mediated lytic gene expression and to repress KSHV reactivation and lytic replication. However, other mutations affect only a subset of these four functions. These findings demonstrate that the lysine residues of IRF-7 play important roles in mediating IFN synthesis and modulating viral lytic replication
Critical Face Pressure of a Tunnel Driven by a Shield Machine Considering Seismic Forces and Tunnel Shape Influence
Evaluating critical face pressure with high accuracy is an important topic for shield tunneling. The existing research focuses more on the influence of complex geological conditions or environmental factors, and there are few reports on the influence of tunnel shape on critical face pressure. In reality, the tunnel shape has a significant impact on the deformation zone in front of the tunnel face, which may lead to non-negligible differences in shield pressure. To fill this gap, an efficient analytical approach is proposed to estimate the critical face pressure considering different tunnel shapes in the framework of limit analysis. As earthquakes are potential threats to the tunnel face stability in seismically active regions, the seismic effect is also taken into account with the help of the pseudo-static method. Several cases with the same area but different tunnel shapes are investigated using the limit analysis method. A comparison with static analysis is given to highlight the influence of seismic forces on the tunnel face stability. The results show that the critical face pressures increase by 15.3% when the tunnel face shape changes from rectangular to circular, and by 23.5% when the horizontal seismic coefficient varies from 0 to 0.1. A further validation with a 3D finite difference method is performed with respect to four typical tunnel shapes considered in this study. Lastly, several stability charts are provided for a quick estimation of the critical tunnel face pressure subjected to seismic forces. It is concluded that the proposed method can be applied to a tunnel stability assessment of various cross-sections and is highly efficient compared with numerical simulations
A Driving Simulation to Analysis and Quantitative Comparison of Driving Behavior of Guide Signs at Intersections
Guide signs are an important source for drivers to obtain road information. However, the evaluation methods for the effectiveness of guide signs are not unified. The quantitative model for evaluating guide signs needs to be constructed to unify the current system of guide signs. This study aims to take the commonly used guide signs in China as the research object to explore the evaluation method of guide signs at intersections. Eight kinds of guide signs were designed and made based on the common layout (layout 1 and layout 2) and the amount of information on signs (3–6). Thirty-four drivers were recruited to organize a driving simulation based on the visual cognitive tasks. Drivers’ legibility time and driver behavior were obtained by using the driving simulator and E-Prime program. A comprehensive quantitative evaluation model of guide signs was established based on the factor analysis method and grey correlation analysis method from the perspective of safe driving. The results show that there is no significant difference in the SD of speed and the SD of acceleration under the influence of various guide signs. The average vehicle speed and acceleration decrease, and the lateral offset distance of the vehicle increases with the amount of information on guide signs increasing. The quantitative evaluation results of guide signs show that the visual security decreases with the increase of the amount of information on guide signs. And layout 2 has better performance than layout 1 when the amount of information on guide signs is the same. This study not only explores the change rule of driving behavior under the influence of guide signs, but also provides a reference for the selection of guide signs
Mitochondrial Fission as a Therapeutic Target for Metabolic Diseases: Insights into Antioxidant Strategies
Mitochondrial fission is a crucial process in maintaining metabolic homeostasis in normal physiology and under conditions of stress. Its dysregulation has been associated with several metabolic diseases, including, but not limited to, obesity, type 2 diabetes (T2DM), and cardiovascular diseases. Reactive oxygen species (ROS) serve a vital role in the genesis of these conditions, and mitochondria are both the main sites of ROS production and the primary targets of ROS. In this review, we explore the physiological and pathological roles of mitochondrial fission, its regulation by dynamin-related protein 1 (Drp1), and the interplay between ROS and mitochondria in health and metabolic diseases. We also discuss the potential therapeutic strategies of targeting mitochondrial fission through antioxidant treatments for ROS-induced conditions, including the effects of lifestyle interventions, dietary supplements, and chemicals, such as mitochondrial division inhibitor-1 (Mdivi-1) and other mitochondrial fission inhibitors, as well as certain commonly used drugs for metabolic diseases. This review highlights the importance of understanding the role of mitochondrial fission in health and metabolic diseases, and the potential of targeting mitochondrial fission as a therapeutic approach to protecting against these conditions
Study on Application of Infrared Spectrum Technology in Power Equipment
In this paper, the application of infrared spectrum acquisition technology in power equipment is studied. Infrared spectrum identification and analysis technology and fault diagnosis technology can monitor and analyze the operation parameters of important equipment in real time, so as to improve the work efficiency of substation staff and achieve higher economic benefits. Therefore, infrared spectrum technology has great practical value and application prospect in power equipment
Ultrasonic welding of CFRTP based on structured surfaces
Ultrasonic plastic welding is an efficient and green welding method, which has been widely used in the joining of carbon fiber reinforced thermoplastic composites (CFRTP) in recent years. An important step in the ultrasonic welding of CFRTP is the design of the welding joint, which largely determines the weld quality. An ultrasonic CFRTP welding method based on structured surfaces was proposed, that is, the surface of the workpiece is structured by ultrasonic embossing before welding, and energy director are processed. Taking carbon fiber reinforced nylon 66 (CF/PA66) as the research object, the effect of structured surface and welding energy on the weld formation was studied. Microstructure, tensile-shear performance and fracture characteristics of welded joint were analyzed. The results show that compared with the unstructured surface, the structured surface acting as energy director that can effectively concentrate welding energy and greatly reduce the randomness and dispersion of weld distribution, thereby improve the weld quality. Moreover, fewer defects in the weld joint can be obtained by pre-structuring two contacting surfaces
Sulfur Isotopic Analysis and Sulfur Source Study of Phosphorite-associated Sulfate from the Ediacaran Doushantuo Formation in Guizhou Province
BACKGROUND: Phosphate deposit of the Ediacaran Doushantuo Formation in Guizhou province is a typical representative of the global phosphorite formation event in the late Neoproterozoic, which is closely related to climate change and evolution of life. However, the current research on the deposition of phosphorus deposits is limited to the mechanism of phosphorus formation and the source of phosphorus, and research on the phosphorus formation process of this deposit and its correlation with the paleo-ocean environment of the same period by isotopic geochemical indicators is relatively weak. OBJECTIVES: In order to determine the sulfur source of phosphorite-associated sulfate. METHODS: Based on the field section observation and the study of petrological characteristics under the microscope, elemental analyzer-isotope ratio mass spectrometry (EA-IRMS) was used to measure the sulfur isotopic composition of phosphorite-associated sulfate from the Ediacaran Doushantuo Formation. RESULTS: The sulfur isotopic composition of phosphorite-associated sulfate ranged from 32.7‰ to 36.9‰ (n=32, mean=34.1‰), which was 11‰ lower than that of the seawater of the same period, indicating that the phosphorite-associated sulfate was not all from the surface seawater. CONCLUSIONS: The idealized early ocean (>520Ma) chemical zoning model indicates that there is a relatively 34S-depleted H2S zone in the seawater at the same time. Combined with the understanding that the source of phosphorus in the phosphorite is closely related to the upwelling, it can be considered that the sulfur isotopic composition of phosphorite-associated sulfate of the Doushantuo Formation represents the mixed signal of surface seawater and upwelling
Study on Application of Infrared Spectrum Technology in Power Equipment
In this paper, the application of infrared spectrum acquisition technology in power equipment is studied. Infrared spectrum identification and analysis technology and fault diagnosis technology can monitor and analyze the operation parameters of important equipment in real time, so as to improve the work efficiency of substation staff and achieve higher economic benefits. Therefore, infrared spectrum technology has great practical value and application prospect in power equipment