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1.
The backbone structure (1,3,4-thiadiazole sulfone derivatives containing amide moiety) of target compounds was determined by modification and optimization of the theoretical design based on commercial chemical carboxin, including molecular docking, scaffold hopping, ligand expansion, etc.In this paper, 23 target compounds were synthesized by the combination of theoretical design and chemical synthesis, and characterized by 1H NMR, 13C NMR and HR MS. Addtionally, the antibacterical bioassay showed that most target compounds performed excellent inhibition on Xanthomonas axonopodis pv. citri (Xac) and Xanthomonas oryzae pv. oryzae (Xoo) in vitro. Meanwhile, molecular docking, molecular dynamics (MD) simulations, and studies on ligand/protein (carboxin/2FBW and 4n/2FBW) complex systems were displayed, and the interaction patterns of ligand/protein complex system were predicted by molecular docking. Besides, the ligand/protein complex system was subject to MD simulation. The analysis of molecular dynamics such as RMSD values suggested that compound/2FBW complexes were stable. MM/GBSA (Molecular mechanics generalized born surface area) dynamic binding affinity results revealed that the active residues (TYR58, HIS26, ARG43, SER39, etc.) played an essential part in the binding of the compound(s) to form a stable low-energy ligand/protein complex, while the MD trajectories demonstrated that the interactions of drugs with 2FBW affected the tertiary structure and increased the stability of protein. Besides, compound 4n also showed control efficacies (curative and protective) on Xoo in vivo, where the curative efficacy was 35.91% and the protective efficacy was 18.97%. In a word, this study showed that 1,3,4-thiadiazole sulfone derivatives containing amide moiety designed based on the structure of carboxin were promising agricultural antibacterial agents, featuring certain stability of binding affinity to proteins and carboxin.  相似文献   
2.
We extracted one new C-methyl flavonoid, farrerol 7-O-β-d-(6-O-galloyl)glucopyranoside (1), along with 11 known flavonoids, from the Cleistocalyx (C.) conspersipunctatus leaves. Elucidation of these flavonoid structures was accomplished through spectroscopic investigation and electronic circular dichroism (ECD) computation. Compared to corosolic acid (IC50: 15.5 ± 0.9 μM), an established inhibitor, the compound 1 (IC50: 6.9 ± 1.2 μM) was found more active in suppressing α-glucosidase. These findings imply the potential of compound 1 as a valid α-glucosidase inhibitor, which also offer evidence for future animal experiments and clinical trials. Besides, molecular docking was employed to explore the probable mechanism for α-glucosidase–compound 1 interaction. The biosynthetic pathway of these flavonoids in C. conspersipunctatus were proposed.  相似文献   
3.
结合无网格局部彼得洛夫-伽辽金(MLPG)方法和径向基函数有限差分(RBF-FD)无网格方法求解非线性热传导问题。MLPG方法属于弱式无网格方法,具有处理边界条件方便的优点,然而因其要做大量的插值、积分运算而计算效率偏低;RBF-FD无网格方法属于强式无网格方法,直接对微分算子进行数值离散,计算效率高,然而其边界条件的处理较复杂。将二者相结合,在求解域边界附近采用MLPG方法,其它区域采用RBF-FD无网格方法,则能扬长避短。介绍了MLPG方法和RBF-FD无网格方法的基本原理,将该混合方法用来求解非线性热传导方程,数值算例显示了方法的正确性和高效性。  相似文献   
4.
Having shown promising performance with high flexibility and efficiency in vehicular edge computing (VEC) network, the parked vehicles (PVs) received an increasing number of attentions in recent years. However, PVs’ residual battery power restricts their running time. In addition, there is still no alternate resource pool for the PVs to cope with the emergencies in the previous VEC framework. To alleviate these problems, we model a cloud-assisted parked vehicular edge computing (PVEC) framework, in which the PVs are classified based on their residual battery power. PVs corporate with the cloud servers (CSs) for the computational resources provision. In addition, we formulate the utilities of the service provider (SP) and PVs and design a contract-based resource allocation problem for the maximization of the SP’s utility. Considering that it is intractable to solve the optimization problem directly, the primal problem is simplified and decoupled into two sub-problems. To design the optimal contracts, we solve the sub-problems by Lagrangian multiplier method and dual function. Simulation results prove that the utilities of PVs can reach to the maximum when they choose the contract corresponding to their types. In addition, the simulation results illustrate the superiority of proposed scheme over previous schemes in improving the utilities of the SP and social welfare.  相似文献   
5.
分子构象的聚类是搜索分子动力学模拟轨迹中代表构象的主要方法。 它是分析复杂构象改变或分子间相互作用机制的关键步骤. 作为一种基于密度的聚类算法,密度峰值搜索算法因其聚类的准确度而被应用于分子聚类过程中. 但随着模拟时长的增长,密度峰值搜索算法较低的计算效率限制了其应用的可能. 本文提出K-means密度峰值搜索算法的聚类算法,它是密度峰值搜索算法在计算效率方面的一个扩展版本,用于解决密度峰值搜索算法中巨大的资源消耗问题. 在K-means密度峰值搜索算法中,首先,通过高效的聚类算法(例如K-means)进行初始聚类,得到的聚类中心被定义为具有权重的典型点. 然后,对加权的典型点通过密度峰值搜索算法实现二次聚类,并细化点为核心点、边界点、加细光晕点. 在与密度峰值搜索算法具有相似的精度的同时,计算复杂度由O(n2)降至O(n). 通过二面角,二级结构,关联图描述的分子构象,将KFDP用于多个模拟轨迹的聚类过程中. 并通过与K-means聚类算法,DBSCAN聚类算法的比较结果,验证了K-means密度峰值搜索算法的优势.  相似文献   
6.
In recent years, more and more attention had been paid to the combination of proteins and flavonoids, and several flavonoids had been reported to improve the physicochemical and emulsifying properties of proteins. This study investigated the effects of ultrasonic treatment (450 W for 10 min, 20 min, and 30 min) on the physicochemical properties, antioxidant activity, and emulsifying properties of soy protein isolate (SPI) -hawthorn flavonoids (HF) non-covalent complexes. The results showed that the addition of HF to SPI and 20 min of ultrasound could reduce α-helix and random coil, increase β-sheet and β-turn, and enhance fluorescence quenching. In addition, it decreased the particle size, zeta potential, surface hydrophobicity, and turbidity to 88.43 or 95.27 nm, −28.80 mV, 1250.42, and 0.23, respectively. The protein solubility, free sulfhydryl group, antioxidant activity, emulsifying activity index, and emulsifying stability index all increased to 73.93%, 15.07 μmol/g, 71.00 or 41.91%, 9.81 m2/g, and 67.71%, respectively. Moreover, high-density small and low-flocculation droplets were formed. Therefore, the combined ultrasound treatment and addition of HF to SPI is a more effective method for protein modification compared to ultrasound treatment alone. It provides a theoretical basis for protein processing and application in the future.  相似文献   
7.
The context of molecular structronics (from “molecular structure” and “electronics”) is that of molecular-level electrochemical storage of energy of sustainable origin (wind, solar). Due to its discontinuous availability, storage of this energy is a key issue. The targeted type of storage relies on implementing “electron reservoirs” within the structronic molecules by electrochemically forming dedicated chemical bonds according to non-catalytic processes. Reservoir bonds are therefore integral parts of the molecular backbone of structronic assemblies. When filled, electron reservoirs manifest themselves in the form of elongated covalent bonds that are to be cleaved for electron releasing (discharging) on demand. The scope of this short review is limited to pyridinium electrophores as particularly suited building blocks for the development of structronics.  相似文献   
8.
暴露于硫酸盐环境中的混凝土输水管易遭受硫酸盐化学侵蚀,导致其耐久性退化、提前失效;而环境中硫酸根离子传输进入混凝土是其化学侵蚀的前提.为获得混凝土内硫酸根离子的扩散进程,首先基于Fick定律及质量守恒定律,建立饱和混凝土管内硫酸根离子的扩散-反应模型.其次,将扩散-反应模型的边界条件齐次化,建立其有限元控制方程.然后,开展硫酸钠溶液中水泥砂浆圆柱试件的腐蚀试验,测定试件不同深度处的硫酸根离子浓度,与模型计算结果对比,以验证模型.最后,开展数值模拟研究,分析混凝土输水管外表面、内外表面暴露于浓度恒定或振荡的硫酸盐溶液情况下管内硫酸根离子浓度的时空分布.  相似文献   
9.
660 MW超临界W火焰锅炉低负荷稳燃特性研究   总被引:1,自引:0,他引:1  
“碳中和”、“碳达峰”的提出预示着未来煤电机组将在更低的负荷运行,用于燃烧无烟煤、贫煤等低挥发份煤种的W火焰锅炉低负荷运行时会出现燃烧稳定性问题。以某660 MW超临界W型火焰锅炉为对象开展了针对低负荷稳燃特性的研究,进行了100%、60%、55%、45%THA工况的试验研究与数值模拟解析,35%THA工况理论预报。结果表明由于炉膛温度降低、煤粉变细、煤粉浓度降低的综合影响,负荷对煤粉颗粒的着火距离影响不大;低负荷工况下投运两侧燃烧器、减少乏气风的射入量有利于提高燃烧稳定性;通过数值模拟可知35%THA工况无法保持炉内高温火焰稳定燃烧,模拟预报锅炉会熄火。  相似文献   
10.
延安是中国共产党领导革命的中心和战略总后方,是革命的红色摇篮。延安时期出版了大量具有历史、文化以及教育意义的红色文献,这些红色文献记载了中国共产党波澜壮阔的发展历程,也反映了延安时期不断发展的科技生产水平与独特的制浆造纸工艺,具有重要的研究价值。然而,延安时期出版的红色文献虽距今不到百年时间,但其保存现状不容乐观,普遍存在纸张老化、焦脆易碎等问题,大量文献急需科学检测与修复保护,以延长其保存寿命。目前,针对延安时期红色文献的检测研究仍存在较大空白。考虑到红色文献的珍贵性与特殊性,应当尽可能选择无损检测方法对其分析检测。基于衰减全反射-傅里叶变换红外光谱法(ATR-FTIR),以木素1 510 cm-1处特征峰与纤维素1 030 cm-1处特征峰的强度作为定量依据,建立了造纸原料与红色文献纸张中木素相对含量的无损检测方法。通过检测不同碱强度与碱浓度处理后的构皮、苦竹与杨木的木素含量,考察了制浆过程中碱处理条件对造纸原料脱木素程度的影响,同时体现了红外光谱法测定木素相对含量的普适性。以复旦大学图书馆藏的76册延安时期红色文献为研究对象,分析了红色文献的纸张木素含量与纸张pH值以及纸张氧化度的相互关系。结果表明,木素相对含量高于25%的红色文献,其纸张pH集中在3~4之间且纸张氧化度较高,文献整体保存状况堪忧;而木素相对含量低于25%的红色文献,其纸张氧化度与酸度较低,文献整体保存情况较好。以上结果验证了红外光谱无损检测法用于延安时期红色文献木素含量分析的可行性,并结合纸张氧化度与酸度数据提出了纸张木素含量的合适范围,为制浆造纸中植物原料的脱木素过程提供参考。拓展了红外光谱法在红色文献无损检测中的应用范围,以期为延安时期红色文献的修复与保护研究提供科学依据。  相似文献   
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