30 research outputs found
Biosynthesis of the active compounds of Isatis indigotica based on transcriptome sequencing and metabolites profiling
Evaluation of the blasting effects of insitu two-to-four lane expansion in the municipal tunnels based on EAHP model
To accurately evaluate the blasting effect of tunnel demolition, guarantee the normal traffic of vehicles during the blasting for insitu two-to-four lane expansion in the municipal tunnels, and reduce the risk of blasting demolition as well as expansion of existing tunnel linings, a comprehensive evaluation model of the tunnel blasting effect based on EAHP was established with the matter-element theory. First, 29 evaluation factors were selected from 5 aspects: blasting scheme design, surroundings of blasting area, blasting quality, blasting materials, blasting safety technology, and 5 evaluation grades were demarcated. Second, the primary correlation function established with extension transformation was adopted to calculate the correlation degree of influencing factors of blasting effects to the evaluation grade, an analytic hierarchy process (AHP) method was introduced to determine the index weight, and the blasting effect grade was determined according to the principle of maximum correlation degree. Therefore, an integrated evaluation method based on Extenics-AHP, namely, EAHP, was established. The results showed that this method was applied to the blasting effect evaluation of the insitu two-to-four lane expansion project in Loushan Tunnel in Zhejiang Province, and the blasting effect evaluation result was Kmax=K2=-0.030 9, namely, the blasting effect evaluation level of the insitu two-to-four lane expansion in the tunnel was "good blasting effect", which was consistent with the actual condition of the project. Therefore, the evaluation indexes and weight coefficients selected based on EAHP model were reasonable and reliable, and the maximum correlation degree obtained by extension transformation could also better reflect the grade of the tunnel blasting effect, indicating this evaluation method had better adaptability to tunnel blasting effect evaluation
Investigation of noncircular orifice supporting baffle longitudinal flow heat exchangers
Owing to the disadvantages of the segmental baffle heat exchanger (SBHE–STHE), a novel type of supporting baffle longitudinal flow heat exchanger is proposed and numerically studied. This equipment includes hexagonal cinquefoil, regular quadrangular, trefoil fillet, and reticulated orifice baffle heat exchangers. The flow and heat transfer performance of the four noncircular orifice supporting baffle longitudinal flow heat exchangers are investigated. Combined sections were fabricated, and local performance characteristics of temperature, pressure, and flow field contours were examined. A composite dimensionless index based on SBHE–STHE is proposed to quickly estimate the comprehensive characteristics of the four supporting baffle longitudinal flow heat exchangers. Results show that the noncircular orifices within the supporting baffle induce jet flow and fluid disturbance. Consequently, periodic pulsating vortices among adjacent supporting baffles are generated, explaining the heat transfer enhancement mechanism. The heat transfer capability of the reticulated orifice baffle heat exchanger is higher than that of the other three orifice baffle schemes and similar to that of the SBHE–STHE. All the comprehensive performance indices of the four noncircular orifice schemes are higher than those of the SBHE–STHE
Efficient synthesis of bio-derived polycarbonates from dimethyl carbonate and isosorbide: regulatingexo-OH andendo-OH reactivity by ionic liquids
It is an immense challenge to design catalysts for synthesizing high molecular weight polycarbonates using CO2, CO2-based compounds, or biorenewable chemicals as building blocks. To this end, an eco-compatible approach to synthesizing polycarbonates from biorenewable isosorbide and CO2-derived dimethyl carbonate (DMC) has been exploited: the regulation of poly(isosorbide carbonate) molecular weight can be achieved by modifying the cation structure of ionic liquid (IL) catalysts. The hydrogen bond donating and accepting ability of ILs can be altered by adjusting the cation structure, which successfully leads to the tunability of the intrinsic imbalance reactivity ofexo-OH andendo-OH in isosorbide. Moreover, these ILs exclusively activate the carbonyl carbon of DMC for accelerating the polymerization reaction. These features are appealing superiorities of ILs as compared to catalysts involving metallic elements. The [Emim]Br catalyst remarkably decreased the imbalanced reactivity of -OH groups of isosorbide, and exhibited the highest catalytic activity. With the presence of [Emim]Br, the poly(isosorbide carbonate) (PIC) weight-average molecular weight and glass transition temperature attained were 52 100 g mol(-1)and 156 degrees C, respectively. Additionally, according to experimental results, DFT calculations, andin situ(1)H NMR analysis, a possible polymerization mechanism indicates that bromine-derived ILs participate in nucleophilic-electrophilic dual-activation in catalyzing PIC synthesis. Our work offers a direction to design catalysts for synthesizing PICs with higher molecular weights through an eco-compatible route
Caprine MAVS Is a RIG-I Interacting Type I Interferon Inducer Downregulated by Peste des Petits Ruminants Virus Infection
The mitochondrial antiviral-signaling protein (MAVS, also known as VISA, IPS-1, or CARDIF) plays an essential role in the type I interferon (IFN) response and in retinoic acid-inducible gene I (RIG-I) mediated antiviral innate immunity in mammals. In this study, the caprine MAVS gene (caMAVS, 1566 bp) was identified and cloned. The caMAVS shares the highest amino acid similarity (98.1%) with the predicted sheep MAVS. Confocal microscopy analysis of partial deletion mutants of caMAVS revealed that the transmembrane and the so-called Non-Characterized domains are indispensable for intracellular localization to mitochondria. Overexpression of caMAVS in caprine endometrial epithelial cells up-regulated the mRNA levels of caprine interferon-stimulated genes. We concluded that caprine MAVS mediates the activation of the type I IFN pathway. We further demonstrated that both the CARD-like domain and the transmembrane domain of caMAVS were essential for the activation of the IFN-β promotor. The interaction between caMAVS and caprine RIG-I and the vital role of the CARD and NC domain in this interaction was demonstrated by co-immunoprecipitation. Upon infection with the Peste des Petits Ruminants Virus (PPRV, genus Morbillivirus), the level of MAVS was greatly reduced. This reduction was prevented by the addition of the proteasome inhibitor MG132. Moreover, we found that viral protein V could interact and colocalize with MAVS. Together, we identified caMAVS as a RIG-I interactive protein involved in the activation of type I IFN pathways in caprine cells and as a target for PPRV immune evasion
Synthesis of bioderived polycarbonates with adjustable molecular weights catalyzed by phenolic-derived ionic liquids
The synthesis of high-molecular-weight bioderived polycarbonates via green routes and regulation of molecular weight is of great significance and is highly challenging. Herein, a green sequential approach toward the synthesis of bio-derived polycarbonates with adjustable molecular weights from isosorbide and dimethyl carbonate (DMC) has been developed by employing ionic liquids (ILs) as a class of eco-friendly catalysts. The structures of IL catalysts can be designed readily to control the molecular weight of isosorbide-derived polycarbonates (PIC), which is an attractive advantage of IL catalysts instead of the conventional metal-containing catalysts. In the presence of the [Bmim][4-I-Phen] catalyst, the PIC weight-average molecular weight (M-w) can reach 50 300 g mol(-1). By the combination of the experimental results and DFT calculations, an IL anion-cation synergistic catalytic polymerization mechanism has been proposed, which reveals the nucleophile-electrophile dual activation by H-bonds and charge-charge interactions in catalyzing the formation of PIC. The significance of this study is that it provides guidance for developing IL catalysts for synthesizing higher molecular weight polycarbonates, thereby conveniently leading to a variety of polymers with tunable properties
Immunogenicity in Rabbits of Virus-Like Particles from a Contemporary Rabbit Haemorrhagic Disease Virus Type 2 (GI.2/RHDV2/b) Isolated in The Netherlands
Rabbit haemorrhagic disease virus (RHDV) type 2 (GI.2/RHDV2/b) is an emerging pathogen in wild rabbits and in domestic rabbits vaccinated against RHDV (GI.1). Here we report the genome sequence of a contemporary RHDV2 isolate from the Netherlands and investigate the immunogenicity of virus-like particles (VLPs) produced in insect cells. RHDV2 RNA was isolated from the liver of a naturally infected wild rabbit and the complete viral genome sequence was assembled from sequenced RT-PCR products. Phylogenetic analysis based on the VP60 capsid gene demonstrated that the RHDV2 NL2016 isolate clustered with other contemporary RHDV2 strains. The VP60 gene was cloned in a baculovirus expression vector to produce VLPs in Sf9 insect cells. Density-gradient purified RHDV2 VLPs were visualized by transmission electron microscopy as spherical particles of around 30 nm in diameter with a morphology resembling authentic RHDV. Immunization of rabbits with RHDV2 VLPs resulted in high production of serum antibodies against VP60, and the production of cytokines (IFN-γ and IL-4) was significantly elevated in the immunized rabbits compared to the control group. The results demonstrate that the recombinant RHDV2 VLPs are highly immunogenic and may find applications in serological detection assays and might be further developed as a vaccine candidate to protect domestic rabbits against RHDV2 infection
Immunogenicity in Rabbits of Virus-Like Particles from a Contemporary Rabbit Haemorrhagic Disease Virus Type 2 (GI.2/RHDV2/b) Isolated in The Netherlands
Immunogenicity in Rabbits of Virus-Like Particles from a Contemporary Rabbit Haemorrhagic Disease Virus Type 2 (GI.2/RHDV2/b) Isolated in The Netherlands
Rabbit haemorrhagic disease virus (RHDV) type 2 (GI.2/RHDV2/b) is an emerging pathogen in wild rabbits and in domestic rabbits vaccinated against RHDV (GI.1). Here we report the genome sequence of a contemporary RHDV2 isolate from the Netherlands and investigate the immunogenicity of virus-like particles (VLPs) produced in insect cells. RHDV2 RNA was isolated from the liver of a naturally infected wild rabbit and the complete viral genome sequence was assembled from sequenced RT-PCR products. Phylogenetic analysis based on the VP60 capsid gene demonstrated that the RHDV2 NL2016 isolate clustered with other contemporary RHDV2 strains. The VP60 gene was cloned in a baculovirus expression vector to produce VLPs in Sf9 insect cells. Density-gradient purified RHDV2 VLPs were visualized by transmission electron microscopy as spherical particles of around 30 nm in diameter with a morphology resembling authentic RHDV. Immunization of rabbits with RHDV2 VLPs resulted in high production of serum antibodies against VP60, and the production of cytokines (IFN-γ and IL-4) was significantly elevated in the immunized rabbits compared to the control group. The results demonstrate that the recombinant RHDV2 VLPs are highly immunogenic and may find applications in serological detection assays and might be further developed as a vaccine candidate to protect domestic rabbits against RHDV2 infection.</p