有机修饰剂对环氧树脂/粘土纳米复合材料结构的影响

分别用质子化的2,4,6-三(二甲氨基甲基)苯酚(HDMP30)、质子化的十八胺(HODA)及氯化胆碱(CC)作为有机修饰剂对原始粘土进行改性,通过"粘土淤浆复合法"合成了环氧树脂/粘土纳米复合材料。采用透射电镜及X射线衍射研究了"粘土淤浆复合法"工艺中有机修饰剂的种类对环氧树脂/粘土纳米复合材料微观结构的影响。结果表明,憎水性的HODA改性粘土所制备的纳米复合材料只能形成插层结构;带有亲水基团羟基的CC改性粘土为剥离与插层混合型结构;而既带有亲水基团又与环氧预聚体有良好相容性的HDMP30改性的粘土则可形成高度无规剥离结构。阐明了3种不同类型有机修饰剂改性粘土所导致的不同微观结构形成的机理。

一类含四甲氧基芴结构可溶性聚酰亚胺的合成及表征

通过三步有机反应合成了一种新型含四甲氧基芴结构的芳香型二胺单体——9,9-双(3,5-二甲氧基-4-(4-氨基苯氧基)苯基)芴,由这种单体分别与4种商品化芳香二酐经过高温缩聚反应,制得一系列含芴结构聚酰亚胺(PI 4a^4d)。分别用傅里叶红外光谱、核磁共振波谱、差示扫描量热及热失重分析等对聚合物的结构和性能进行了表征和研究。该类聚酰亚胺在甲基吡咯烷酮(NMP)、二甲基乙酰胺(DMAc)、二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)等高沸点溶剂及CHCl_3、CH_2Cl_2等低沸点溶剂中具有优异的溶解性;所制得的薄膜具有良好的力学性能,其拉伸强度为62.1~75.6 MPa,断裂伸长率在16.0%~20.7%之间,弹性模量为1.8~2.6 GPa。该系列聚酰亚胺的玻璃化转变温度在244~256℃之间,空气和氮气中10%热失重温度均在430℃以上,表现出优异的热学性能。

Steroidal saponins with anti-inflammatory activity from Tribulus terrestris L.

Objective:Tribulus terrestris L.(T.terrestris)is a highly valuable traditional Chinese medicine used to treat stroke,inflammation,pulmonary fibrosis,liver cancer,and urolithiasis.To identify the basic substance responsible for the anti-inflammatory effect of TST(total saponins of Tribulus),its chemical composition was systematically studied,and its effect of inhibiting nitric oxide generation and the expression of related inflammatory factors were determined.Methods:To separate chemical constituents from T.terrestris by column chromatography.Spectroscopic methods,including 1D and 2D nuclear magnetic resonance spectroscopy(NMR)and mass spectrometry(MS)techniques,were used to elucidate the isolated compounds.The anti-inflammatory activities of TST and several compounds were evaluated in vitro.Results:Fifteen steroidal saponins,including 9 furostanol steroidal saponins(1,2,3,4,5,6,7,8,and 15)and 6 isospirostanol steroidal saponins(9,10,11,12,13,and 14),were isolated from T.terrestris.TST significantly decreased the expression of tumor necrosis factor-a(TNF-a)and interleukin-6(IL-6)in RAW 264.7 cells stimulated by lipopolysaccharides.Compounds 13 and 15 evidently reduced TNF-a expression.Compounds 6,10,12,13,and 15 markedly reduced IL-6 expression.Conclusions:Compounds 1 was a novel furostanol steroidal saponin,named 26-O-b-D-glucopyranosyl-(25R)-5afurostan-12-carbonyl-20(22)-en-3b,26-diol-3-O-{b-D-xylopyranosyl-(1→2)-[b-D-xylopyranosyl-(1→3)]-b-D-glucopyranosyl-(1→4)-[a-L-rhamnopyranosyl-(1→2)]-b-D-galactopyranoside}.Compounds 2 was isolated from the family Zygophyllaceae for the first time,and 5 and 6 were isolated from the Tribulus genus.TST and compounds 6,10,12,13,and 15 exerts antiinflammatory activity.

Licorice and its main components on the treatment of diabetes and its complications:A review of in vivo and in vitro studies

Licorice is one of the oldest herbal medicines for its various ethno pharmacological uses.In both Asian and European countries,it has been recorded for treatment of inflammatory diseases.A large number of ingredients have been isolated from licorice,including triterpene saponins and flavonoids,which are normally being considered to be the main biologically active components.In the last decade,licorice has been proved exert anti-diabetic effect in various in vivo and in vitro models of diabetes mellitus.Furthermore,licorice can also antagonize all sorts of diabetes complications,including diabetic nephropathy,atherosclerosis,diabetic retinopathy and neuropathy.Except anti-inflammation,licorice and its active components show anti-diabetic effects by improving insulin resistance and increasing insulin secretion,regulating lipid metabolism,and anti-oxidation.The useful effects of licorice and its active components are due to regulating different pathways and proteins,including NF-κB,AMPK,insulin signaling pathway,MAPK,etc.In this review,we provide an overview of the beneficial effects and related molecular mechanism of licorice and its effective components on improving diabetes and its complications.

Main alkaloids of Rhizoma Coptidis improved palmitic acidinduced insulin resistance in HepG2 cells via AMPK and MAPK signaling pathway

Rhizoma Coptidis,a traditional Chinese herbal medicine,has been used for treating diabetes for thousands of years.However,the molecular basis for this action has not been elucidated.In the present study,the effects of seven main alkaloids of Rhizoma Coptidis on glycometabolism were investigated and the related molecular mechanism of five active compounds on insulin resistant(IR)cell model was explored for the first time.Results showed that berberine,palmatine,epiberberine,columbamine and groenlandicine enhanced glucose consumption in the palmitic acid(PA)-induced IR-HepG2 cells,indicating that these compounds could improve IR.In addition,we found that among these active alkaloids,berberine,columbamine,epiberberine and groenlandicine could inhibit the activation of ERK and p38 pathway,while berberine,columbamine,palmatine and epiberberine could activate AMPK pathway.Moreover,palmatine and columbamine regulated the mRNA expression of GLUT2 to ameliorate IR via activating AMPK and inactivating p38 MAPK signal pathway.To sum up,berberine,columbamine,palmatine,epiberberine and groenlandicine might be the active reagents,which contribute to the glucose lowering effects of Rhizoma Coptidis.

Ratiometric fluorescence immunoassay of SARS-CoV-2 nucleocapsid protein via Si-FITC nanoprobe-based inner filter effect

The global pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)virus has necessitated rapid,easy-to-use,and accurate diagnostic methods to monitor the virus infection.Herein,a ratiometric fluorescence enzyme-linked immunosorbent assay(ELISA)was developed using Si-fluorescein isothiocyanate nanoparticles(FITC NPs)for detecting SARSCoV-2 nucleocapsid(N)protein.Si-FITC NPs were prepared by a one-pot hydrothermal method using 3-aminopropyl triethoxysilane(APTES)-FITC as the Si source.This method did not need post-modification and avoided the reduction in quantum yield and stability.The p-nitrophenyl(pNP)produced by the alkaline phosphatase(ALP)-mediated hydrolysis of pnitrophenyl phosphate(pNPP)could quench Si fluorescence in Si-FITC NPs via the inner filter effect.In ELISA,an immunocomplex was formed by the recognition of capture antibody/N protein/reporter antibody.ALP-linked secondary antibody bound to the reporter antibody and induced pNPP hydrolysis to specifically quench Si fluorescence in Si-FITC NPs.The change in fluorescence intensity ratio could be used for detecting N protein,with a wide linearity range(0.01-10.0 and 50-300 ng/mL)and low detection limit(0.002 ng/mL).The concentration of spiked SARS-CoV-2 N protein could be determined accurately in human serum.Moreover,this proposed method can accurately distinguish coronavirus disease 2019(COVID-19)and non-COVID-19 patient samples.Therefore,this simple,sensitive,and accurate method can be applied for the early diagnosis of SARS-CoV-2 virus infection.

新型冠状病毒肺炎个性化通风防控的非均布评价方法

通风是预防新型冠状病毒室内传播的重要手段,个性化通风作为一种高效的通风方式在疾控方面具有较好的应用前景.个性化通风作为舒适性通风已在公共交通工具上得到广泛应用,其在新型冠状病毒肺炎疫情防控方面的作用需要进一步探索.然而,大部分空气感染风险预测模型基于室内病原体均匀分布的假设,不考虑呼吸活动产生的病原体近距离传播的问题以及局部通风的作用,因而无法准确预测新型冠状病毒在非均布状态下的传播风险.本文通过暖体假人及颗粒物实验对5种非均布风险评价模型进行验证,其中包括暴露风险系数(εbz)、暴露有效性系数(personal exposure effectiveness,PEE)、吸入比(intake fraction,IF)、剂量反应模型(P(t))和感染风险降低比(η),利用5种模型分别评价了个性化通风的保护效应,并探讨了模型应用于新型冠状病毒传播风险评价时的适用性.结果表明,5种评价方法均基于暴露者呼吸区飞沫浓度测量结果,能够预测个性化通风对飞沫传播风险的干预作用,其反映的规律基本一致.暴露风险指标εbz、PEE、IF及感染风险指标η可预测病毒相对暴露水平,适用于新型冠状病毒暴露风险的简单预测.剂量反应模型能够预测新型冠状病毒的感染风险,其病毒活性及感染性的准确测定是模型应用的关键.以上模型均能反映个性化通风在感染源使用时由飞沫横向传播和加速扩散引起的风险提高问题,及其保护效应与风险降低水平.本文结果将为评价及发展以疾控为目标的新型通风方式提供支持,为评价非均布状态下的新型冠状病毒传播风险提供依据.