A dynamic dissemination model for recurring online public opinion

Nonlinear Dynamics - With an increasing number of people sharing feelings and opinions online, the online platforms have become one of the most important channels for public opinion dissemination....     

Tb3+离子发光探针研究Ca2+,La3+和Al3+与拟南芥钙调素的竞争结合

利用Tb3 离子的发光, 研究了Tb3 与拟南芥钙调素 (CaM)结合的荧光光谱及荧光滴定曲线特点, 然后利用Tb3 4*CaM系统在221 nm直接激发和280 nm敏化激发的光谱变化研究了Ca2 , La3 和Al3 与拟南芥钙调素 (CaM) 的竞争结合作用. 结果表明: Tb3 , La3 与钙调素的竞争结合能力强于Ca2 , 而Tb3 的竞争结合力又大于La3 , Ca2 与钙调素的结合力远大于Al3 . 竞争实验的结果从分子水平上揭示了Tb3 , La3 和Al3 等金属离子生物效应可能的分子机制.     

Analysis of sialic acid levels in Chinese intravenous immunoglobulins by high‐performance liquid chromatography with fluorescence detection

Intravenous immunoglobulin (IVIg) is increasingly used for the treatment of autoimmune and systemic inflammatory diseases with both licensed and off‐label indications. Recent studies indicated that IVIg‐mediated immunomodulation and anti‐inflammation are closely associated with the IgG sialylation, especially with IgG crystallizable fragment (Fc) sialylation. The sialic acid levels of the IgG molecules and Fc fragments in 12 IVIg preparations from six Chinese manufacturers were evaluated. The Fc fragments were derived from the papain digestion of IVIg, followed by affinity and size exclusion chromatography. The sialic acid levels in Fc fragments and IVIg preparations were determined by high‐performance liquid chromatography with fluorescence detection, after the sialic acid residues were released from the proteins. The results showed that the sialic acid levels in Chinese IVIg preparations ranged from 0.875 (mol/mol IgG) to 1.085 (mol/mol IgG), and the sialic acid levels in Fc fragments were from 0.321 (mol/mol Fc) to 0.361 (mol/mol Fc). Furthermore, the sialic acid levels of IVIg preparations and Fc fragments from different Chinese manufactures were significantly different. These findings will contribute to an increased understanding of Chinese IVIg preparations and the relationship between the sialic acid levels in IVIg preparations and their clinical efficacy in future clinical studies.     

One‐Pot Synthesis of Pomegranate‐Structured Fe3O4/Carbon Nanospheres‐Doped Graphene Aerogel for High‐Rate Lithium Ion Batteries

A unique hierarchically nanostructured composite of iron oxide/carbon (Fe₃O₄/C) nanospheres‐doped three‐dimensional (3D) graphene aerogel has been fabricated by a one‐pot hydrothermal strategy. In this novel nanostructured composite aerogel, uniform Fe₃O₄ nanocrystals (5–10 nm) are individually embedded in carbon nanospheres (ca. 50 nm) forming a pomegranate‐like structure. The carbon matrix suppresses the aggregation of Fe₃O₄ nanocrystals, avoids direct exposure of the encapsulated Fe₃O₄ to the electrolyte, and buffers the volume expansion. Meanwhile, the interconnected 3D graphene aerogel further serves to reinforce the structure of the Fe₃O₄/C nanospheres and enhances the electrical conductivity of the overall electrode. Therefore, the carbon matrix and the interconnected graphene network entrap the Fe₃O₄ nanocrystals such that their electrochemical function is retained even after fracture. This novel hierarchical aerogel structure delivers a long‐term stability of 634 mA h g^?1 over 1000 cycles at a high current density of 6 A g^?1 (7 C), and an excellent rate capability of 413 mA h g^?1 at 10 A g^?1 (11 C), thus exhibiting great potential as an anode composite structure for durable high‐rate lithium‐ion batteries.     

Auto‐Oxidative Coupling of Glycine Derivatives

The unprecedented title reaction between glycine derivatives and indoles, as well as the auto‐oxidative Povarov/aromatization tandem reaction of glycine derivatives with olefins are described. The reactions were performed in the absence of redox‐active catalysts and chemical oxidants under mild reaction conditions. Only simple organic solvents and air (or O₂) were required.     

Preparation and photocatalytic property of CeO2 lamellar

A novel room temperature solid-state chemical synthesis was introduced to successfully fabricate CeO₂ samples, coupled by a polyethylene glycol 400 (PEG 400)/cetyl trimethylammonium bromide (CTAB)/sodium dodecyl sulfate (SDS). The as-prepared products were characterized by XRD, TEM, SEM, BET and UV. A study of photocatalytic degradation of the methylene blue MB under UV illumination has been carried out. It is indicated that the samples exhibit excellent photocatalytic activity. Besides, the samples assisted with surfactants possess higher photocatalytic activity than the sample without any surfactants, wherein the sample with SDS as an additive shows the highest photocatalytic activity, which is able to reach 89.6% MB degradation ratio within 60 min illumination. Moreover, the effects of important operational parameters such as initial MB concentration, catalyst loading and pH were also investigated. The above sample under the optimum conditions obtained the maximum MB degradation ratio up to 96.5%, which is higher than that of the commercial TiO₂ P25 under the same conditions. It can be concluded that CeO₂ will be a potential photocatalyst in the application of organic pollutant.     

4-甲基-4-氮杂-21E-苯亚甲基-5-孕烯-3,20-二酮类化合物的合成

报道了一种以KF/Al_2O_3催化合成4-甲基-4-氮杂-21E-苯亚甲基-5-孕烯-3,20-二酮类化合物的方法。以黄体酮为原料,经NaIO_4/KMnO_4氧化裂解、胺解关环得到重要中间体4-甲基-4-氮杂-5-孕烯-3,20-二酮,后者在KF/Al_2O_3催化下经克莱森缩合得到目标产物。考察了不同的催化剂、反应温度、催化剂用量对目标产物的影响。条件优化的结果为:n(3)∶n(KF/Al_2O_3)=1∶1,回流状态下反应4 h,产率为56%~68%。此方法适用性好,为4-氮杂甾体苯亚甲基衍生物的合成提供了一种方便而有效的方法。     

Identification of Metabolites of Epimedin A in Rats Using UPLC/Q–TOF–MS

Herba Epimedii (Epimedium) is a kind of tonic herb, widely used in China. Epimedin A is a major component of Herba Epimedii with bioactivities. Analysis of the metabolic profile in vivo plays a pivotal role in understanding how traditional Chinese medicine works. And the metabolites of epimedin A might influence the effects of Herba Epimedii. Moreover, the metabolic routes of epimedin A provide an important basis for safety evaluation. Until now, little has been known about the metabolism of epimedin A. The current study was designed to characterize the metabolic pathways of epimedin A in vivo. The metabolites in rat plasma, bile, feces, and urine were identified by UPLC/Q–TOF–MS analysis. A total of 27 metabolites from epimedin A were detected or tentatively identified. The major metabolic processes were hydrolysis, hydrogenation, hydroxylation, dehydrogenation, demethylation, and conjugation with glucuronic acid and different sugars. The present study revealed the metabolic pathways of epimedin A in rat for the first time, and epimedin A could undergo extensive phase I and phase II metabolism in rat. These findings would provide an important basis for the further study and clinical application of epimedin A. In addition, the results of this work have shown the feasibility of the UPLC/Q–TOF–MS approach for rapid and reliable characterization of metabolites.     

双模板法制备具有介孔孔壁的三维有序大孔二氧化铈及其改善的低温还原性能

以聚甲基丙烯酸甲酯(PMMA)为硬模板,三嵌段共聚物F127、十六烷基三甲基溴化铵(CTAB)或聚乙二醇(PEG)为软模板剂(表面活性剂),柠檬酸为络合剂,硝酸铈为金属前驱体,采用双模板法成功地合成出具有介孔孔壁的三维有序大孔(3DOM)结构的立方相CeO2样品CeO2-F127,CeO2-CTAB和CeO2-PEG,...