BACKGROUND Modern pharmacological studies have confirmed that plant-derived compounds from Puerariae flos(PF)has significant biological activities against liver damage,tumors and inflammation.Kakkatin is an isoflavone...BACKGROUND Modern pharmacological studies have confirmed that plant-derived compounds from Puerariae flos(PF)has significant biological activities against liver damage,tumors and inflammation.Kakkatin is an isoflavone polyphenolic compound isolated from PF flower.However,the effect of kakkatin and its derivatives on anti-tumor has not been well explored.AIM To design and synthesize a kakkatin derivative[6-(hept-6-yn-1-yloxy)-3-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one(HK)]to explore its anti-tumor biological activity.METHODS Hept-6-yn-1-yl ethanesulfonate was introduced to replace hydrogen at the hydroxyl position of kakkatin phenol,and the derivative of kakkatin was prepared;the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was used to detect cell viability,a clone formation assay was adopted to detect cell proliferation,apoptosis,necrosis,and cell cycles were analyzed by Annexin V/propidium iodide staining and flow cytometry.Cell migration and invasion ability were evaluated by cell scratch assay and transwell assay.The potential mechanism of HK on hepatocellular carcinoma(HCC)SMMC-7721 cells was explored through network pharmacology and molecular docking,and finally real-time PCR assays was used to verify the potential targets and evaluate the biological activity of HK.RESULTS Compared with kakkatin,the modified HK did not significantly increase the inhibitory activity of gastric cancer MGC803 cells,but the inhibitory activity of HCC SMMC-7721 cells was increased by about 30 times,with an IC50 value of 2.5μM,and the tumor inhibition effect was better than cisplatin,which could significantly inhibit the cloning,invasion and metastasis of HCC SMMC-7721 cells,and induce apoptosis and G2/M cycle arrest.Its mechanism of action is mainly related to the upregulation of PDE3B and NFKB1 target proteins in the cAMP pathway.CONCLUSION HK have a significant inhibitory effect on HCC SMMC-7721 cells,and the targets of their action may be PDE3B and NFKB1 proteins in the cAMP pathway,making it a good lead drug for the treatment of HCC.展开更多
[Objectives]The anti-tumor activity of fractions from Buddleja officinalis Maxim.by petroleum ether,ethyl acetate,n-butanol and water solvent was studied.[Methods]The ethanol extract from B.officinalis Maxim.was extra...[Objectives]The anti-tumor activity of fractions from Buddleja officinalis Maxim.by petroleum ether,ethyl acetate,n-butanol and water solvent was studied.[Methods]The ethanol extract from B.officinalis Maxim.was extracted and then concentrated with petroleum ether,ethyl acetate,n-butanol and water,respectively,and the extracts were obtained.The inhibitory effects of the four different fractions on the growth of three tumor cell lines in vitro were detected by CCK-8 method,and the median inhibitory concentration(IC 50 value)was calculated.[Results]The four fractions inhibited the growth of the three tumor cell lines in vitro,among which the n-butanol fraction had the best anti-tumor activity.The IC 50 values of the n-butanol fraction on human gastric cancer(SGC-7901),human breast cancer(MCF-7)and human liver cancer(BEL-7404)cell lines were 0.08,1.58 and 0.12 mg/mL,respectively.[Conclusions]Petroleum ether,ethyl acetate,n-butanol and water fractions from the ethanol extract of B.officinalis Maxim.had certain anti-tumor effects,and the n-butanol fraction had the best anti-tumor activity.展开更多
Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a n...Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a non-destructive and non-interruptive method to measure NO 3 gradients and electric potential differences across both the plasma membrane and tonoplast. Thus, a double-barrelled microelectrode backfilled with a membrane sensor for NO 3 embedded in poly vinyl chloride (PVC) can record the NO 3 activity in cytoplasm and vacuole of a cell. This paper presented how to make this kind of microelectrode and how to do the intracellular measurements on intact plants. Our result showed that nitrate activity was about 2.7 mmol L 1 in cytoplasm while 70 mmol L 1 in vacuole, which implicated that vacuole was a pool of nitrate in plants.展开更多
Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In...Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.展开更多
In the present work,comparative molecular field analysis(CoMFA)techniques were used to perform three-dimensional quantitative structure-activity relationship(3D-QSAR)studies on the anti-tumor activity(pHi,i=1,2,3,4)of...In the present work,comparative molecular field analysis(CoMFA)techniques were used to perform three-dimensional quantitative structure-activity relationship(3D-QSAR)studies on the anti-tumor activity(pHi,i=1,2,3,4)of N-aryl-salicylamide derivatives against four cancer cell lines,including A549,MCF-7,SGC-7901,and Bel-7402.12 compounds were randomly selected as the training set to establish the prediction models,which were verified by the test set of 5 compounds containing template molecule.The contributions of steric and electrostatic fields to pH1,pH2,pH3,and pH4 were 23.8% and 76.2%,20.1% and 79.9%,18.7% and 81.3%,and 14.3%and 85.7%,respectively.The cross-validation(Rcv 2)and non-cross-validation coefficients(R2)were 0.826 and 0.963 for pH1,0.867 and 0.974 for pH2,0.941 and 0.989 for pH3,and 0.797 and 0.961 for pH4,respectively.The CoMFA models were then used to predict the activities of the compounds,and it was found that the models had strong stability and good predictability.Based on the CoMFA contour maps,some key structural factors responsible for the anticancer activity of the series of compounds were revealed.The results provide some useful theoretical references for understanding the mechanism of action,designing new N-aryl-salicylamide derivatives with high anti-tumor activity,and predicting their activities.展开更多
Ursolic acid was modified at C3 and C28 position to obtain fourteen derivatives including twelve novel compounds, and their chemical structures were characterized by IR, ^1H NMR and MS. Cell growth inhibitory effects ...Ursolic acid was modified at C3 and C28 position to obtain fourteen derivatives including twelve novel compounds, and their chemical structures were characterized by IR, ^1H NMR and MS. Cell growth inhibitory effects of the derivatives against Hela cell were evaluated by MTT assay. All these derivatives were found to have stronger cell growth inhibitory than their parent compound, ursolic acid. The derivatives with a substituted acetyl group at C3 hydroxyl group show better activities than those with an unsubstituted hydroxyl group.展开更多
Surface properties (viz. surface area, basicity/base strength distribution, and crystal phases) of alkali metal doped CaO (alkali metal/Ca= 0.1 and 0.4) catalysts and their catalytic activity/selectivity in oxidat...Surface properties (viz. surface area, basicity/base strength distribution, and crystal phases) of alkali metal doped CaO (alkali metal/Ca= 0.1 and 0.4) catalysts and their catalytic activity/selectivity in oxidative coupling of methane (OCM) to higher hydrocarbons at different reaction conditions (viz. temperature, 700 and 750 ℃; CH4/O2 ratio, 4.0 and 8.0 and space velocity, 5140-20550 cm^3 ·g^-1·h^-1) have been investigated. The influence of catalyst calcination temperature on the activity/selectivity has also been investigated. The surface properties (viz. surface area, basicity/base strength distribution) and catalytic activity/selectivity of the alkali metal doped CaO catalysts are strongly influenced by the alkali metal promoter and its concentration in the alkali metal doped CaO catalysts. An addition of alkali metal promoter to CaO results in a large decrease in the surface area but a large increase in the surface basicity (strong basic sites) and the C2+ selectivity and yield of the catalysts in the OCM process. The activity and selectivity are strongly influenced by the catalyst calcination temperature. No direct relationship between surface basicity and catalytic activity/selectivity has been observed. Among the alkali metal doped CaO catalysts, Na-CaO (Na/Ca = 0.1, before calcination) catalyst (calcined at 750 ℃), showed best performance (C2+ selectivity of 68.8% with 24.7% methane conversion), whereas the poorest performance was shown by the Rb-CaO catalyst in the OCM process.展开更多
Bimetallic Fe-Mn nano catalysts supported on carbon nanotubes(CNTs) were prepared using microemulsion technique with water-to-surfactant ratios of 0.4-1.6. The nano catalysts were extensively characterized by differen...Bimetallic Fe-Mn nano catalysts supported on carbon nanotubes(CNTs) were prepared using microemulsion technique with water-to-surfactant ratios of 0.4-1.6. The nano catalysts were extensively characterized by different methods and their activity and selectivity in Fischer-Tropsch synthesis(FTS) have been assessed in a fixed-bed microreactor. The physicochemical properties and performance of the nanocatalysts were compared with the catalyst prepared by impregnation method. Very narrow particle size distribution has been produced by the microemulsion technique at relatively high loading of active metal. TEM images showed that small metal nano particles in the range of 3–7 nm were not only confined inside the CNTs but also located on the outer surface of the CNTs. Using microemulsion technique with water to surfactant ratio of0.4 decreased the average iron particle sizes to 5.1 nm. The reduction percentage and dispersion percentage were almost doubled. Activity and selectivity were found to be dependent on the catalyst preparation method and average iron particle size. CO conversion and FTS rate increased from 49.1% to 71.0% and 0.144 to 0.289 gHC/(gcat h), respectively. While the WGS rate decreased from 0.097 to 0.056 gCO2/(gcat h). C5+liquid hydrocarbons selectivity decreased slightly and olefins selectivity almost doubled.展开更多
The water-soluble part(GS) of Ganoderma sinense Zhao, Xu et Zhang was divided into high molecular(GS-H) and low molecular(GS-L) parts by Cellulose Super Filtration, and GS was also fractionated into four fractio...The water-soluble part(GS) of Ganoderma sinense Zhao, Xu et Zhang was divided into high molecular(GS-H) and low molecular(GS-L) parts by Cellulose Super Filtration, and GS was also fractionated into four fractions, GS-1, 2, 3, and 4 by ethanol precipitation according to their molecular weights. Chemical analysis shows that GS and GS-1, 2, 3, 4 were complexes of polysaccharide and peptide. The fractions with molecular weights over 4000, GS-1, 2, 3, and GS-H show anti-tumor activities, however, the fractions with molecular weights lower than 4000, GS-4, and GS-L have no anti-tumor activity, indicating that the anti-tumor activity of Ganoderma Sinensis was caused by glucopeptides with molecular weight ranging from 4000 to 20000. Two purified glucopeptides, GS-6b and GS-7b were obtained from GS-H by ion-exchange and gel-permeation chromatography. Their molecular weights, glycosidic linkages, and configurations were detected by means of IR spectrum, sugar composition analysis, and methylation analysis. The polysaccharide parts of GS-6b and GS-7b had glucan backbone consisting of β-1→3 Glc, and side chain containing glucosyl, mannosyl, fucosyl, xylosyl, galactosyl, and glucuronic acid residues attached on 1-2, 1-4, 1-6 positions of the backbone of GS-6b, or 1-6, 1-4 positions of the backbone of GS-7b. The peptide parts in GS-6b and GS-7b were composed of 10 kinds of amino acids, including Asp, Ser, Arg, Gly, Thr, Pro, Ala, Val, Met, and Lys.展开更多
Zero or negative emissions of carbon dioxide(CO2)is the need of the times,as inexorable rising and alarming levels of CO2 in the atmosphere lead to global warming and severe climate change.The electrochemical CO2 redu...Zero or negative emissions of carbon dioxide(CO2)is the need of the times,as inexorable rising and alarming levels of CO2 in the atmosphere lead to global warming and severe climate change.The electrochemical CO2 reduction(eCO2R)to value‐added fuels and chemicals by using renewable electricity provides a cleaner and more sustainable route with economic benefits,in which the key is to develop clean and economical electrocatalysts.Carbon‐based catalyst materials possess desirable properties such as high offset potential for H2 evolution and chemical stability at the negative applied potential.Although it is still challenging to achieve highly efficient carbon‐based catalysts,considerable efforts have been devoted to overcoming the low selectivity,activity,and stability.Here,we summarize and discuss the recent progress in carbon‐based metal‐free catalysts including carbon nanotubes,carbon nanofibers,carbon nanoribbons,graphene,carbon nitride,and diamonds with an emphasis on their activity,product selectivity,and stability.In addition,the key challenges and future potential approaches for efficient eCO2R to low carbon‐based fuels are highlighted.For a good understanding of the whole history of the development of eCO2R,the CO2 reduction reactions,principles,and techniques including the role of electrolytes,electrochemical cell design and evaluation,product selectivity,and structural composition are also discussed.The metal/metal oxides decorated with carbon‐based electrocatalysts are also summarized.We aim to provide insights for further development of carbon‐based metal‐free electrocatalysts for CO2 reduction from the perspective of both fundamental understanding and technological applications in the future.展开更多
Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile...Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.展开更多
BACKGROUND Liuweiwuling Tablet(LWWL)is a Chinese patent medicine approved for the treatment of chronic inflammation caused by hepatitis B virus(HBV)infection.Previous studies have indicated an anti-HBV effect of LWWL,...BACKGROUND Liuweiwuling Tablet(LWWL)is a Chinese patent medicine approved for the treatment of chronic inflammation caused by hepatitis B virus(HBV)infection.Previous studies have indicated an anti-HBV effect of LWWL,specifically in terms of antigen inhibition,but the underlying mechanism remains unclear.AIM To investigate the potential mechanism of action of LWWL against HBV.METHODS In vitro experiments utilized three HBV-replicating and three non-HBV-replicating cell lines.The in vivo experiment involved a hydrodynamic injectionmediated mouse model with HBV replication.Transcriptomics and metabolomics were used to investigate the underlying mechanisms of action of LWWL.RESULTS In HepG2.1403F cells,LWWL(0.8 mg/mL)exhibited inhibitory effects on HBV DNA,hepatitis B surface antigen and pregenomic RNA(pgRNA)at rates of 51.36%,24.74%and 50.74%,respectively.The inhibition rates of LWWL(0.8mg/mL)on pgRNA/covalently closed circular DNA in HepG2.1403F,HepG2.2.15 and HepG2.A64 cells were 47.78%,39.51%and 46.74%,respectively.Integration of transcriptomics and metabolomics showed that the anti-HBV effect of LWWL was primarily linked to pathways related to apoptosis(PI3K-AKT,CASP8-CASP3 and P53 pathways).Apoptosis flow analysis revealed that the apoptosis rate in the LWWL-treated group was significantly higher than in the control group(CG)among HBV-replicating cell lines,including HepG2.2.15(2.92%±1.01%vs 6.68%±2.04%,P<0.05),HepG2.A64(4.89%±1.28%vs 8.52%±0.50%,P<0.05)and HepG2.1403F(3.76%±1.40%vs 7.57%±1.35%,P<0.05)(CG vs LWWL-treated group).However,there were no significant differences in apoptosis rates between the non-HBV-replicating HepG2 cells(5.04%±0.74%vs 5.51%±1.57%,P>0.05),L02 cells(5.49%±0.80%vs 5.48%±1.01%,P>0.05)and LX2 cells(6.29%±1.54%vs 6.29%±0.88%,P>0.05).TUNEL staining revealed a significantly higher apoptosis rate in the LWWL-treated group than in the CG in the HBVreplicating mouse model,while no noticeable difference in apoptosis rates between the two groups was observed in the non-HBV-replicating mouse model.CONCLUSION Preliminary results suggest that LWWL exerts a potent inhibitory effect on wild-type and drug-resistant HBV,potentially involving selective regulation of apoptosis.These findings offer novel insights into the anti-HBV activities of LWWL and present a novel mechanism for the development of anti-HBV medications.展开更多
The effects of surface strain and subsurface promoters, which are both important factors in heterogeneous catalysis, on catalytic selectivity and activity of Pd are examined in this study by considering the selective ...The effects of surface strain and subsurface promoters, which are both important factors in heterogeneous catalysis, on catalytic selectivity and activity of Pd are examined in this study by considering the selective hydrogenation of acetylene as an example. Combined density functional theory calculations and microkinetic modeling reveal that the selectivity and activity of the Pd catalyst for acetylene hydrogenation can both be substantially influenced by the effects of Pd lattice strain variation and subsurface carbon species formation on the adsorption properties of the reactants and products. It is found that the adsorption energies of the reactants and products are, in general, linearly scaled with the lattice strain for both pristine and subsurface carbon atom-modified Pd(111) surfaces, except for the adsorption of C_2H_2 over Pd(111)-C. The activity for ethylene formation typically corresponds to the region of strong reactants adsorption in the volcano curve; such an effect of lattice strain and the presence of subsurface promoters can improve the activity of the catalyst through the weakening of the adsorption of reactants. The activity and selectivity for Pd(111)-C are always higher than those for the pristine Pd(111) surfaces with respect to ethylene formation. Based on the results obtained, Pd-based catalysts with shrinking lattice constants are suggested as good candidates for the selective hydrogenation of acetylene. A similar approach can be used to facilitate the future design of novel heterogeneous catalysts.展开更多
To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstru...To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.展开更多
Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadoli...Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadolinium ion selective electrode besides the effects of their structures.1.Effect of preparation process of the grafted polymers on the properties ofgadolinium ion selective electrodesThe electrode membranes which consist of functional polymers as active materials were prepared by re-action of gadolinium chloride with the radiation grafted clmer of acrlic acid and polystyrene of which展开更多
A new synthetic route to polyamides and hydroxyl polyamides was established, based on the selecting (?)-acylation of three novel typical active diesters: the active diester of N-hydroxy- (?) 4-epoxy-5-cyclohexene-2, 3...A new synthetic route to polyamides and hydroxyl polyamides was established, based on the selecting (?)-acylation of three novel typical active diesters: the active diester of N-hydroxy- (?) 4-epoxy-5-cyclohexene-2, 3-dicarboximide( HOEC), such as N, N'-(temphthaloyldioxy) bis(1, 4- epoxy - 5 - cyclohexene- 2, 3 - dicarboximide.) ( PBOEC), N, N'- ( isophthaloyl - dioxy) bis (1,4-epoxy-5-cyclohexene-2, 3-dicarboximide)(IPBOEC) and N, N' -(adipoyldioxy) his (1,4-epoxy-5-cyclohexene-2, 3-dicarboximide) ( ADOEC)with aliphatic diamines and 1,3-diamino-2-hydroxypropane. The polycondensation occurs at room temperature in solution without added catalyst. Dipolar aprotic solvents which include dimethyl sulfoxide, N- methyl - 2- pyrrolidone and dimethylformamide were used as solvents for polymerization. The selective N-acylation of two active diesters was performed as a model reaction study.展开更多
Twenty-five derivatives of glycyrrhetinic acid(GA) modified on the A-ring,at C30 and C11 positions were synthesized.Their in vitro cytotoxicity against various cancer cell lines[henrietta lacks strain of cancer cell...Twenty-five derivatives of glycyrrhetinic acid(GA) modified on the A-ring,at C30 and C11 positions were synthesized.Their in vitro cytotoxicity against various cancer cell lines[henrietta lacks strain of cancer cells(HeLa),human hepatocellular liver carcinoma cells(HepG2) and human gastric carcinoma cells(BGC-823)] was evaluated by standard MTT[3-(4,5-dimethyl-2-thiazol-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay.All the tested derivatives were found to have stronger cell growth inhibitory than their parent compound GA.Among them,compounds 3a,5a,and 8d have similar activity on HeLa cell line,and compound 8a has similar activity on HeLa,HepG2 and BGC-823 cell lines as Gefitinib.展开更多
In this paper, a selective activation strategy is studied in order to alleviate the issue of added compliance in the intrinsic cohesive zone model applied to arbitrary crack propagation. This strategy proceeds by firs...In this paper, a selective activation strategy is studied in order to alleviate the issue of added compliance in the intrinsic cohesive zone model applied to arbitrary crack propagation. This strategy proceeds by first inserting cohesive elements between bulk elements and subsequently tying the duplicated nodes across the interface using controllable multi-point constraints before the analysis begins. Then, during the analysis, a part of the multi-point constraints are selectively released, thereby reactivating the corresponding cohesive elements and allowing cracks to initiate and propagate along the bulk element boundaries. The strategy is implemented in Abaqus/Standard using a user-defined multi-point constraint subroutine. Analysis results indicate that the strategy significantly alleviates the added compliance problem and reduces the computation time.展开更多
Taking isovanillin and the important products synthesized from raw materials of isovanillin as objects,this paper reviews its pharmacological effects and molecular mechanisms,including inhibiting tumor angiogenesis,bl...Taking isovanillin and the important products synthesized from raw materials of isovanillin as objects,this paper reviews its pharmacological effects and molecular mechanisms,including inhibiting tumor angiogenesis,blocking cancer cell self-repair,inducing cancer cell DNA fragmentation,cytotoxicity,inhibiting tumor growth,regulating brain nerves,inhibiting renin and other pharmacological effects,etc.,which provide new ideas for the in-depth research and development of isovanillin.展开更多
[Objectives]The paper was to establish the quality standard for freeze-dried tablets of Polygonatum sibiricum and to explore the antitumor activity of its extract diosgenin.[Methods]Taking freeze-dried powder samples ...[Objectives]The paper was to establish the quality standard for freeze-dried tablets of Polygonatum sibiricum and to explore the antitumor activity of its extract diosgenin.[Methods]Taking freeze-dried powder samples of P.sibiricum from 4 different producing areas as materials,and referring to the quality standard of P.sibiricum in the Chinese Pharmacopoeia(2020 edition),the contents of total ash,moisture,extract,total sugar and diosgenin were determined by total ash determination method,drying method,hot dipping method,0.2%anthrone-sulfuric acid method and HPLC,respectively.The antitumor activities of diosgenin against A431(human epidermal carcinoma cells),H1975(human lung adenocarcinoma cells)and Ramos(human B lymphoblastoma cells)were investigated by MTT assay.[Results]The moisture content of the samples was 2.8%-4.7%(not more than 18.0%);the total ash content was 1.9%-3.4%(not more than 4.0%);the ethanol-soluble extract content was 72.99%-78.99%(not less than 45.0%);and the total sugar content was 7.95%-9.94%(not less than 7.0%).The lowest content of diosgenin was 0.18%,and diosgenin was significantly resistant to A431.[Conclusions]The content determination method established in the study is simple,accurate and reproducible.展开更多
文摘BACKGROUND Modern pharmacological studies have confirmed that plant-derived compounds from Puerariae flos(PF)has significant biological activities against liver damage,tumors and inflammation.Kakkatin is an isoflavone polyphenolic compound isolated from PF flower.However,the effect of kakkatin and its derivatives on anti-tumor has not been well explored.AIM To design and synthesize a kakkatin derivative[6-(hept-6-yn-1-yloxy)-3-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one(HK)]to explore its anti-tumor biological activity.METHODS Hept-6-yn-1-yl ethanesulfonate was introduced to replace hydrogen at the hydroxyl position of kakkatin phenol,and the derivative of kakkatin was prepared;the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was used to detect cell viability,a clone formation assay was adopted to detect cell proliferation,apoptosis,necrosis,and cell cycles were analyzed by Annexin V/propidium iodide staining and flow cytometry.Cell migration and invasion ability were evaluated by cell scratch assay and transwell assay.The potential mechanism of HK on hepatocellular carcinoma(HCC)SMMC-7721 cells was explored through network pharmacology and molecular docking,and finally real-time PCR assays was used to verify the potential targets and evaluate the biological activity of HK.RESULTS Compared with kakkatin,the modified HK did not significantly increase the inhibitory activity of gastric cancer MGC803 cells,but the inhibitory activity of HCC SMMC-7721 cells was increased by about 30 times,with an IC50 value of 2.5μM,and the tumor inhibition effect was better than cisplatin,which could significantly inhibit the cloning,invasion and metastasis of HCC SMMC-7721 cells,and induce apoptosis and G2/M cycle arrest.Its mechanism of action is mainly related to the upregulation of PDE3B and NFKB1 target proteins in the cAMP pathway.CONCLUSION HK have a significant inhibitory effect on HCC SMMC-7721 cells,and the targets of their action may be PDE3B and NFKB1 proteins in the cAMP pathway,making it a good lead drug for the treatment of HCC.
基金Supported by Guangxi Key R&D Project(GuiKeAB18221095)Baise Scientific Research and Technology Development Plan of Baise City(BaiKe20211810)+1 种基金Open Project of Scientific Research in Guangxi Key Laboratory of Molecular Pathology of Hepatobiliary Diseases(GXZDSYS-005)Research Project of High-level Talents in Youjiang Medical University for Nationalities(01002018079).
文摘[Objectives]The anti-tumor activity of fractions from Buddleja officinalis Maxim.by petroleum ether,ethyl acetate,n-butanol and water solvent was studied.[Methods]The ethanol extract from B.officinalis Maxim.was extracted and then concentrated with petroleum ether,ethyl acetate,n-butanol and water,respectively,and the extracts were obtained.The inhibitory effects of the four different fractions on the growth of three tumor cell lines in vitro were detected by CCK-8 method,and the median inhibitory concentration(IC 50 value)was calculated.[Results]The four fractions inhibited the growth of the three tumor cell lines in vitro,among which the n-butanol fraction had the best anti-tumor activity.The IC 50 values of the n-butanol fraction on human gastric cancer(SGC-7901),human breast cancer(MCF-7)and human liver cancer(BEL-7404)cell lines were 0.08,1.58 and 0.12 mg/mL,respectively.[Conclusions]Petroleum ether,ethyl acetate,n-butanol and water fractions from the ethanol extract of B.officinalis Maxim.had certain anti-tumor effects,and the n-butanol fraction had the best anti-tumor activity.
基金supported by the National Natural Science Foundation of China(30270790).
文摘Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a non-destructive and non-interruptive method to measure NO 3 gradients and electric potential differences across both the plasma membrane and tonoplast. Thus, a double-barrelled microelectrode backfilled with a membrane sensor for NO 3 embedded in poly vinyl chloride (PVC) can record the NO 3 activity in cytoplasm and vacuole of a cell. This paper presented how to make this kind of microelectrode and how to do the intracellular measurements on intact plants. Our result showed that nitrate activity was about 2.7 mmol L 1 in cytoplasm while 70 mmol L 1 in vacuole, which implicated that vacuole was a pool of nitrate in plants.
基金supported by the renewable energy and hydrogen projects in National Key Research and Development Plan of China(2019YFB1505000).
文摘Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.
基金supported by the National Natural Science Foundation of China(21075138)the special fund of State Key Laboratory of Structural Chemistry(20160028)
文摘In the present work,comparative molecular field analysis(CoMFA)techniques were used to perform three-dimensional quantitative structure-activity relationship(3D-QSAR)studies on the anti-tumor activity(pHi,i=1,2,3,4)of N-aryl-salicylamide derivatives against four cancer cell lines,including A549,MCF-7,SGC-7901,and Bel-7402.12 compounds were randomly selected as the training set to establish the prediction models,which were verified by the test set of 5 compounds containing template molecule.The contributions of steric and electrostatic fields to pH1,pH2,pH3,and pH4 were 23.8% and 76.2%,20.1% and 79.9%,18.7% and 81.3%,and 14.3%and 85.7%,respectively.The cross-validation(Rcv 2)and non-cross-validation coefficients(R2)were 0.826 and 0.963 for pH1,0.867 and 0.974 for pH2,0.941 and 0.989 for pH3,and 0.797 and 0.961 for pH4,respectively.The CoMFA models were then used to predict the activities of the compounds,and it was found that the models had strong stability and good predictability.Based on the CoMFA contour maps,some key structural factors responsible for the anticancer activity of the series of compounds were revealed.The results provide some useful theoretical references for understanding the mechanism of action,designing new N-aryl-salicylamide derivatives with high anti-tumor activity,and predicting their activities.
基金Natural Science Foundation of Liaoning Province of China (No.20042009)Science and Technology Foundation of Shenyang City of China(No.20050785)
文摘Ursolic acid was modified at C3 and C28 position to obtain fourteen derivatives including twelve novel compounds, and their chemical structures were characterized by IR, ^1H NMR and MS. Cell growth inhibitory effects of the derivatives against Hela cell were evaluated by MTT assay. All these derivatives were found to have stronger cell growth inhibitory than their parent compound, ursolic acid. The derivatives with a substituted acetyl group at C3 hydroxyl group show better activities than those with an unsubstituted hydroxyl group.
文摘Surface properties (viz. surface area, basicity/base strength distribution, and crystal phases) of alkali metal doped CaO (alkali metal/Ca= 0.1 and 0.4) catalysts and their catalytic activity/selectivity in oxidative coupling of methane (OCM) to higher hydrocarbons at different reaction conditions (viz. temperature, 700 and 750 ℃; CH4/O2 ratio, 4.0 and 8.0 and space velocity, 5140-20550 cm^3 ·g^-1·h^-1) have been investigated. The influence of catalyst calcination temperature on the activity/selectivity has also been investigated. The surface properties (viz. surface area, basicity/base strength distribution) and catalytic activity/selectivity of the alkali metal doped CaO catalysts are strongly influenced by the alkali metal promoter and its concentration in the alkali metal doped CaO catalysts. An addition of alkali metal promoter to CaO results in a large decrease in the surface area but a large increase in the surface basicity (strong basic sites) and the C2+ selectivity and yield of the catalysts in the OCM process. The activity and selectivity are strongly influenced by the catalyst calcination temperature. No direct relationship between surface basicity and catalytic activity/selectivity has been observed. Among the alkali metal doped CaO catalysts, Na-CaO (Na/Ca = 0.1, before calcination) catalyst (calcined at 750 ℃), showed best performance (C2+ selectivity of 68.8% with 24.7% methane conversion), whereas the poorest performance was shown by the Rb-CaO catalyst in the OCM process.
文摘Bimetallic Fe-Mn nano catalysts supported on carbon nanotubes(CNTs) were prepared using microemulsion technique with water-to-surfactant ratios of 0.4-1.6. The nano catalysts were extensively characterized by different methods and their activity and selectivity in Fischer-Tropsch synthesis(FTS) have been assessed in a fixed-bed microreactor. The physicochemical properties and performance of the nanocatalysts were compared with the catalyst prepared by impregnation method. Very narrow particle size distribution has been produced by the microemulsion technique at relatively high loading of active metal. TEM images showed that small metal nano particles in the range of 3–7 nm were not only confined inside the CNTs but also located on the outer surface of the CNTs. Using microemulsion technique with water to surfactant ratio of0.4 decreased the average iron particle sizes to 5.1 nm. The reduction percentage and dispersion percentage were almost doubled. Activity and selectivity were found to be dependent on the catalyst preparation method and average iron particle size. CO conversion and FTS rate increased from 49.1% to 71.0% and 0.144 to 0.289 gHC/(gcat h), respectively. While the WGS rate decreased from 0.097 to 0.056 gCO2/(gcat h). C5+liquid hydrocarbons selectivity decreased slightly and olefins selectivity almost doubled.
文摘The water-soluble part(GS) of Ganoderma sinense Zhao, Xu et Zhang was divided into high molecular(GS-H) and low molecular(GS-L) parts by Cellulose Super Filtration, and GS was also fractionated into four fractions, GS-1, 2, 3, and 4 by ethanol precipitation according to their molecular weights. Chemical analysis shows that GS and GS-1, 2, 3, 4 were complexes of polysaccharide and peptide. The fractions with molecular weights over 4000, GS-1, 2, 3, and GS-H show anti-tumor activities, however, the fractions with molecular weights lower than 4000, GS-4, and GS-L have no anti-tumor activity, indicating that the anti-tumor activity of Ganoderma Sinensis was caused by glucopeptides with molecular weight ranging from 4000 to 20000. Two purified glucopeptides, GS-6b and GS-7b were obtained from GS-H by ion-exchange and gel-permeation chromatography. Their molecular weights, glycosidic linkages, and configurations were detected by means of IR spectrum, sugar composition analysis, and methylation analysis. The polysaccharide parts of GS-6b and GS-7b had glucan backbone consisting of β-1→3 Glc, and side chain containing glucosyl, mannosyl, fucosyl, xylosyl, galactosyl, and glucuronic acid residues attached on 1-2, 1-4, 1-6 positions of the backbone of GS-6b, or 1-6, 1-4 positions of the backbone of GS-7b. The peptide parts in GS-6b and GS-7b were composed of 10 kinds of amino acids, including Asp, Ser, Arg, Gly, Thr, Pro, Ala, Val, Met, and Lys.
基金The authors thank the financial support from the“Scientific and Technical Innovation Action Plan”Basic Research Field of the Shanghai Science and Technology Committee(19JC1410500)the Fundamental ResearchFunds for the Central Universities(2232018A3‐06)the National Natural Science Foundation of China(91645110).
文摘Zero or negative emissions of carbon dioxide(CO2)is the need of the times,as inexorable rising and alarming levels of CO2 in the atmosphere lead to global warming and severe climate change.The electrochemical CO2 reduction(eCO2R)to value‐added fuels and chemicals by using renewable electricity provides a cleaner and more sustainable route with economic benefits,in which the key is to develop clean and economical electrocatalysts.Carbon‐based catalyst materials possess desirable properties such as high offset potential for H2 evolution and chemical stability at the negative applied potential.Although it is still challenging to achieve highly efficient carbon‐based catalysts,considerable efforts have been devoted to overcoming the low selectivity,activity,and stability.Here,we summarize and discuss the recent progress in carbon‐based metal‐free catalysts including carbon nanotubes,carbon nanofibers,carbon nanoribbons,graphene,carbon nitride,and diamonds with an emphasis on their activity,product selectivity,and stability.In addition,the key challenges and future potential approaches for efficient eCO2R to low carbon‐based fuels are highlighted.For a good understanding of the whole history of the development of eCO2R,the CO2 reduction reactions,principles,and techniques including the role of electrolytes,electrochemical cell design and evaluation,product selectivity,and structural composition are also discussed.The metal/metal oxides decorated with carbon‐based electrocatalysts are also summarized.We aim to provide insights for further development of carbon‐based metal‐free electrocatalysts for CO2 reduction from the perspective of both fundamental understanding and technological applications in the future.
文摘Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.
基金Supported by National Natural Science Foundation of China,No.81930110The National Funded Postdoctoral Researcher Program of China,No.GZC20232406+2 种基金Henan Province Traditional Chinese Medicine Science Research Project,No.2023ZY3040Henan Province Medical Science and Technology Research Plan Joint Construction Project,No.LHGJ20230233National Key Research and Development Program of China,No.2022YFC2303103.
文摘BACKGROUND Liuweiwuling Tablet(LWWL)is a Chinese patent medicine approved for the treatment of chronic inflammation caused by hepatitis B virus(HBV)infection.Previous studies have indicated an anti-HBV effect of LWWL,specifically in terms of antigen inhibition,but the underlying mechanism remains unclear.AIM To investigate the potential mechanism of action of LWWL against HBV.METHODS In vitro experiments utilized three HBV-replicating and three non-HBV-replicating cell lines.The in vivo experiment involved a hydrodynamic injectionmediated mouse model with HBV replication.Transcriptomics and metabolomics were used to investigate the underlying mechanisms of action of LWWL.RESULTS In HepG2.1403F cells,LWWL(0.8 mg/mL)exhibited inhibitory effects on HBV DNA,hepatitis B surface antigen and pregenomic RNA(pgRNA)at rates of 51.36%,24.74%and 50.74%,respectively.The inhibition rates of LWWL(0.8mg/mL)on pgRNA/covalently closed circular DNA in HepG2.1403F,HepG2.2.15 and HepG2.A64 cells were 47.78%,39.51%and 46.74%,respectively.Integration of transcriptomics and metabolomics showed that the anti-HBV effect of LWWL was primarily linked to pathways related to apoptosis(PI3K-AKT,CASP8-CASP3 and P53 pathways).Apoptosis flow analysis revealed that the apoptosis rate in the LWWL-treated group was significantly higher than in the control group(CG)among HBV-replicating cell lines,including HepG2.2.15(2.92%±1.01%vs 6.68%±2.04%,P<0.05),HepG2.A64(4.89%±1.28%vs 8.52%±0.50%,P<0.05)and HepG2.1403F(3.76%±1.40%vs 7.57%±1.35%,P<0.05)(CG vs LWWL-treated group).However,there were no significant differences in apoptosis rates between the non-HBV-replicating HepG2 cells(5.04%±0.74%vs 5.51%±1.57%,P>0.05),L02 cells(5.49%±0.80%vs 5.48%±1.01%,P>0.05)and LX2 cells(6.29%±1.54%vs 6.29%±0.88%,P>0.05).TUNEL staining revealed a significantly higher apoptosis rate in the LWWL-treated group than in the CG in the HBVreplicating mouse model,while no noticeable difference in apoptosis rates between the two groups was observed in the non-HBV-replicating mouse model.CONCLUSION Preliminary results suggest that LWWL exerts a potent inhibitory effect on wild-type and drug-resistant HBV,potentially involving selective regulation of apoptosis.These findings offer novel insights into the anti-HBV activities of LWWL and present a novel mechanism for the development of anti-HBV medications.
基金supported by the National Natural Science Foundation of China(21603142)the Shanghai Pujiang Program(16PJ1406800)the Shanghai Young Eastern Scholar Program(QD2016049)~~
文摘The effects of surface strain and subsurface promoters, which are both important factors in heterogeneous catalysis, on catalytic selectivity and activity of Pd are examined in this study by considering the selective hydrogenation of acetylene as an example. Combined density functional theory calculations and microkinetic modeling reveal that the selectivity and activity of the Pd catalyst for acetylene hydrogenation can both be substantially influenced by the effects of Pd lattice strain variation and subsurface carbon species formation on the adsorption properties of the reactants and products. It is found that the adsorption energies of the reactants and products are, in general, linearly scaled with the lattice strain for both pristine and subsurface carbon atom-modified Pd(111) surfaces, except for the adsorption of C_2H_2 over Pd(111)-C. The activity for ethylene formation typically corresponds to the region of strong reactants adsorption in the volcano curve; such an effect of lattice strain and the presence of subsurface promoters can improve the activity of the catalyst through the weakening of the adsorption of reactants. The activity and selectivity for Pd(111)-C are always higher than those for the pristine Pd(111) surfaces with respect to ethylene formation. Based on the results obtained, Pd-based catalysts with shrinking lattice constants are suggested as good candidates for the selective hydrogenation of acetylene. A similar approach can be used to facilitate the future design of novel heterogeneous catalysts.
基金Open Fund of Key Laboratory of Ministry of Education for Metallurgical Emission Reduction and Comprehensive Utilization of Resources,China(No.JKF19-08)General Project of Science and Technology Plan of Yunnan Science and Technology Department,China(No.2019FB077)+1 种基金Industrialization Cultivation Project of Scientific Research Fund of Yunnan Provincial Department of Education,China(No.2016CYH07)Top Young Talents of Yunnan Ten Thousand Talents Plan,China(No.YNWR-QNBJ-2019-263)。
文摘To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.
文摘Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadolinium ion selective electrode besides the effects of their structures.1.Effect of preparation process of the grafted polymers on the properties ofgadolinium ion selective electrodesThe electrode membranes which consist of functional polymers as active materials were prepared by re-action of gadolinium chloride with the radiation grafted clmer of acrlic acid and polystyrene of which
文摘A new synthetic route to polyamides and hydroxyl polyamides was established, based on the selecting (?)-acylation of three novel typical active diesters: the active diester of N-hydroxy- (?) 4-epoxy-5-cyclohexene-2, 3-dicarboximide( HOEC), such as N, N'-(temphthaloyldioxy) bis(1, 4- epoxy - 5 - cyclohexene- 2, 3 - dicarboximide.) ( PBOEC), N, N'- ( isophthaloyl - dioxy) bis (1,4-epoxy-5-cyclohexene-2, 3-dicarboximide)(IPBOEC) and N, N' -(adipoyldioxy) his (1,4-epoxy-5-cyclohexene-2, 3-dicarboximide) ( ADOEC)with aliphatic diamines and 1,3-diamino-2-hydroxypropane. The polycondensation occurs at room temperature in solution without added catalyst. Dipolar aprotic solvents which include dimethyl sulfoxide, N- methyl - 2- pyrrolidone and dimethylformamide were used as solvents for polymerization. The selective N-acylation of two active diesters was performed as a model reaction study.
基金Supported by the Project-sponsored by Scientific Research Foundation for Returned Overseas Chinese Scholars,Ministry of Education of China(No.20080890)the Key Project of Chinese University Science Research of Liaoning Educational Commission,China(No.L2010433)
文摘Twenty-five derivatives of glycyrrhetinic acid(GA) modified on the A-ring,at C30 and C11 positions were synthesized.Their in vitro cytotoxicity against various cancer cell lines[henrietta lacks strain of cancer cells(HeLa),human hepatocellular liver carcinoma cells(HepG2) and human gastric carcinoma cells(BGC-823)] was evaluated by standard MTT[3-(4,5-dimethyl-2-thiazol-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay.All the tested derivatives were found to have stronger cell growth inhibitory than their parent compound GA.Among them,compounds 3a,5a,and 8d have similar activity on HeLa cell line,and compound 8a has similar activity on HeLa,HepG2 and BGC-823 cell lines as Gefitinib.
文摘In this paper, a selective activation strategy is studied in order to alleviate the issue of added compliance in the intrinsic cohesive zone model applied to arbitrary crack propagation. This strategy proceeds by first inserting cohesive elements between bulk elements and subsequently tying the duplicated nodes across the interface using controllable multi-point constraints before the analysis begins. Then, during the analysis, a part of the multi-point constraints are selectively released, thereby reactivating the corresponding cohesive elements and allowing cracks to initiate and propagate along the bulk element boundaries. The strategy is implemented in Abaqus/Standard using a user-defined multi-point constraint subroutine. Analysis results indicate that the strategy significantly alleviates the added compliance problem and reduces the computation time.
基金Supported by the Central Talent Training Fund for Local University Reform and Development(2020GSP16).
文摘Taking isovanillin and the important products synthesized from raw materials of isovanillin as objects,this paper reviews its pharmacological effects and molecular mechanisms,including inhibiting tumor angiogenesis,blocking cancer cell self-repair,inducing cancer cell DNA fragmentation,cytotoxicity,inhibiting tumor growth,regulating brain nerves,inhibiting renin and other pharmacological effects,etc.,which provide new ideas for the in-depth research and development of isovanillin.
基金Supported by Key S&T Special Projects of Yunnan Department of Science and Technology(2018F004)National Natural Science Foundation of China(31900300)。
文摘[Objectives]The paper was to establish the quality standard for freeze-dried tablets of Polygonatum sibiricum and to explore the antitumor activity of its extract diosgenin.[Methods]Taking freeze-dried powder samples of P.sibiricum from 4 different producing areas as materials,and referring to the quality standard of P.sibiricum in the Chinese Pharmacopoeia(2020 edition),the contents of total ash,moisture,extract,total sugar and diosgenin were determined by total ash determination method,drying method,hot dipping method,0.2%anthrone-sulfuric acid method and HPLC,respectively.The antitumor activities of diosgenin against A431(human epidermal carcinoma cells),H1975(human lung adenocarcinoma cells)and Ramos(human B lymphoblastoma cells)were investigated by MTT assay.[Results]The moisture content of the samples was 2.8%-4.7%(not more than 18.0%);the total ash content was 1.9%-3.4%(not more than 4.0%);the ethanol-soluble extract content was 72.99%-78.99%(not less than 45.0%);and the total sugar content was 7.95%-9.94%(not less than 7.0%).The lowest content of diosgenin was 0.18%,and diosgenin was significantly resistant to A431.[Conclusions]The content determination method established in the study is simple,accurate and reproducible.