Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles...Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles of different forms of atomically-dispersed metals(i.e.,single-atoms and atomic clusters)in photocatalytic reactions remain ambiguous.Herein,we developed an ethylenediamine(EDA)-assisted reduction method to controllably synthesize atomically dispersed Au in the forms of Au single atoms(Au_(SA)),Au clusters(Au_(C)),and a mixed-phase of Au_(SA)and Au_(C)(Au_(SA+C))on CdS.In addition,we elucidate the synergistic effect of Au_(SA)and Au_(C)in enhancing the photocatalytic performance of CdS substrates for simultaneous CO_(2)reduction and aryl alcohol oxidation.Specifically,Au_(SA)can effectively lower the energy barrier for the CO_(2)→*COOH conversion,while Au_(C)can enhance the adsorption of alcohols and reduce the energy barrier for dehydrogenation.As a result,the Au_(SA)and Au_(C)co-loaded CdS show impressive overall photocatalytic CO_(2)conversion performance,achieving remarkable CO and BAD production rates of 4.43 and 4.71 mmol g^(−1)h^(−1),with the selectivities of 93%and 99%,respectively.More importantly,the solar-to-chemical conversion efficiency of Au_(SA+C)/CdS reaches 0.57%,which is over fivefold higher than the typical solar-to-biomass conversion efficiency found in nature(ca.0.1%).This study comprehensively describes the roles of different forms of atomically-dispersed metals and their synergistic effects in photocatalytic reactions,which is anticipated to pave a new avenue in energy and environmental applications.展开更多
For the aim of finding new available functional materials, a series of nitrogen heteroatom 2 β naphthylbenzoxazole molecules were designed based on the experiment and theoretical studies of 2 β naphthylb...For the aim of finding new available functional materials, a series of nitrogen heteroatom 2 β naphthylbenzoxazole molecules were designed based on the experiment and theoretical studies of 2 β naphthylbenzoxazole molecule. Geometry optimization of the 2 β naphthylbenzoxazole was carried out by using Hyperchem Molecular Mechanics plus MM+. The planar molecular structure was obtained. The quantum chemistry calculating method PPP SCF CI, which is specially available to treat electron spectrum, was applied to investigate each novel designed molecules. Their electronic structures were analyzed in detail, it shows that total π electron energy decreased linearly with the number of replaced nitrogen. Single nitrogen atom located in benzoxazole ring or naphthalene ring results in contrary changes of level difference of FMO; multiple nitrogen atoms located in different molecular positions will lead to polarization of extremum in the level difference of FMO; and 5 nitrogen heteroatoms reach the culmination. Considering other electronic structure information, some favorable designed molecules were identified.展开更多
TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,t...TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,the presence of alcohol and the temperature were carefully investigated on the crystallization process.The high alkalinity was proved to be highly important for the preservation of the microsphere morphology initially formed,due to the unique intergrown stacking style.An alkali treatment with the aqueous solution of structure-directing agent,organic amine and ammonium salt and subsequent Na+ion-exchange were performed to enhance the catalytic activity of TS-2 microsphere in the cyclohexanone ammoximation reactions,with both the conversion and selectivity higher than 99%.In the continuous reaction,the TS-2 microspheres exhibited to be durable catalyst with potential application in industrial ammoximation processes.展开更多
In this paper, by using symbolic and algebra computation, Chen and Wang＇s multiple R/ccati equations rational expansion method was further extended. Many double soliton-like and other novel combined forms of exact so...In this paper, by using symbolic and algebra computation, Chen and Wang＇s multiple R/ccati equations rational expansion method was further extended. Many double soliton-like and other novel combined forms of exact solutions of the （2＋1）-dimensional Breaking soliton equation are derived by using the extended multiple Riccatl equations expansion method.展开更多
Objective： To explore the molecular basis of the effects of Gancao （Radix Glycyrrhizae, GC） on inflammation throughthe inhibition of cyclooxygenase 2 （COX-2）. Methods： The Discovery Studio 4.5 System was used to...Objective： To explore the molecular basis of the effects of Gancao （Radix Glycyrrhizae, GC） on inflammation throughthe inhibition of cyclooxygenase 2 （COX-2）. Methods： The Discovery Studio 4.5 System was used to predict thephysicochemical properties of GC molecular compounds. The Ligand Profiler was used to screen for natural GCcomponents that could combine with the COX-2 pharmacophores. The AutoDock Vina 1.1.2 software was used for themolecular docking of the natural GC components with the COX-2 protein. Results： The aromatics were the closest to thenon-steroidal anti-inflammatory drugs in terms of the three properties, namely molecular weight, molecular surface area,and molecular solubility, followed by the flavonoids; whereas the terpenoids/saponins differed most from thenon-steroidal anti-inflammatory drugs in terms of the three properties; and the aliphatics were inconsistent. One hundredand eighteen small molecules were obtained through the pharmacophore screening using GC. The molecular bindingenergy （MBE） results demonstrated that the MBE value of the flavonoids/aromatics, obtained from their binding with theCOX-2 protein, was lower than that obtained from their binding with the substrate, metabolism of arachidonic acid,whereas the MBE value of the aliphatics/terpenoids, obtained from their binding with the COX-2 protein, was higherthan that obtained from their binding with the substrate, arachidonic acid. Finally, further filtration, based on thephysicochemical properties and the molecular binding energies of the small molecules, was carried out. Forty-twonatural GC components, including 35 flavonoid and 7 aromatic constituents, with low binding energies and potentialinhibitory effects on COX-2, were screened. Conclusion： Using the three-step program, pharmacophore screening,molecular docking, and physicochemical properties analysis, we screened out 35 flavonoid molecules and 7 aromaticmolecules, which may be potential COX-2 inhibitors, from GC. Two of the 35 flavonoid molecules （licochalcone A andglabridin） have been confirmed in the laboratory to have inhibitory effects on COX-2. Our findings provide a materialbasis for the development of non-steroidal GC drugs.展开更多
Objective To explore the pharmacological mechanism of active saponin compounds of Tuchao Baibiandouren(Lablab Semen Album fried with earth,TCBBDR)in treating type 2 diabetes(T2DM)using UHPLC-Q-Exactive Orbitrap MS and...Objective To explore the pharmacological mechanism of active saponin compounds of Tuchao Baibiandouren(Lablab Semen Album fried with earth,TCBBDR)in treating type 2 diabetes(T2DM)using UHPLC-Q-Exactive Orbitrap MS and network pharmacology.Methods UHPLC-Q-Exactive Orbitrap MS was used for a qualitative analysis of saponin compounds in TCBBDR.PharmMapper and CTD were used to screen drug active compounds and disease targets,and an active compound-target network was constructed via Cytoscape 3.8.0.Molecular docking was applied with the drug active compounds and key targets using AutoDock Vina 1.1.2,and a trajectory for the molecular dynamics simulation was completed by GROMACS 2019-3.Results Sixteen saponin compounds were identified from TCBBDR,along with 292 saponin compoud targets and 792 T2DM targets.Through Venn analysis of target saponin constituents and T2DM related targets,a total of 91 intersection targets were screened out in the treatment of T2DM with saponin.The mean values of degree,betweenness centrality and closeness centrality were taken as the thresholds to screen out 22 key genes,among which 4 key proteins namely MAPK1,IGF1 EGFR,PIK3R1 were selected in the top 10 key genes.On this basis,the saponin active constituent-target-signaling pathway network was established.The Gene Ontology(GO)enrichment analysis showed that the related biological modules included activity of steroid hormone receptor,steroid binding,and insulin receptor binding,etc.;the related signaling pathways were EGFR,PI3K-Akt and MAPK,etc.;regulating signaling pathways like MAPK could induce the proliferation,inhibition and apoptosis of pancreaticβcells,increase the quantity of pancreaticβcells,improve the functions of pancreaticβcells and stimulate the insulin secretion.Docking experiment analysis showed that all selected saponin compounds could enter the active sites of targets and form 3–14 hydrogen bonds with residues of the active sites.Moreover,van der Waals forces were present between chemical compounds and active sites.By combining the docking binding energy,we determined that the chemical compounds showed strong binding energy to the targets.Conclusion TCBBDR exerts therapeutic effects on diabetes through multi-compound and multi-target collaboration.Specifically,saponin components mediate pathways including inflammatory reaction and signal transduction to treat T2DM by regulating several key proteins that interact with EGFR and a series of signaling pathways related to disease development.展开更多
Structural and electronic properties of PbnAgn(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetallic Pb...Structural and electronic properties of PbnAgn(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetallic PbnAgn(n=2–12)clusters were viewed as the initial structures,then,those were calculated by ab initio molecular dynamics(AIMD)to search possible global minimum energy structures of PbnAgn clusters,finally,the ground state structures of PbnAgn(n=2–12)clusters were achieved.According to the structural evolution of lowest energy structures,Ag atoms prefer gather in the central sites while Pb atoms prefer external positions in PbnAgn(n=2–12)clusters,which is in excellent agreement with experimental results from literature and the application in metallurgy.The average binding energies,HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities,chemical hardnessη,HOMO orbits,LUMO orbits and density of states of PbnAgn(n=2–12)clusters were calculated.The results indicate that the values of HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities and chemical hardnessηshow obvious odd-even oscillations when n≤5,PbnAgn(n=2–12)clusters become less chemically stable and show insulator-to-metal transition with the variation of cluster size n,PbnAgn(n≥9)cluster are good candidates to study the properties of PbAg alloys.Those can be well explained by the density of states(DOS)distributions of Pb atoms and Ag atoms between–0.5 Ha and 0.25 Ha in PbnAgn(n=2–12)clusters.展开更多
The molecular structure of N, N-bis ( 2-chloroethyl )-N'-isopropyl-N'-phenyl thioureido phosphoramide has been determined by X-ray diffraction method. The crystal(C_14H_23Cl_4N_4OPS) is monoclinic with space g...The molecular structure of N, N-bis ( 2-chloroethyl )-N'-isopropyl-N'-phenyl thioureido phosphoramide has been determined by X-ray diffraction method. The crystal(C_14H_23Cl_4N_4OPS) is monoclinic with space group P21/n,α=13. 398(2) , b= 10. 351(4), c= 14. 595(3) A, β= 101. 45(1)°, V=1983(2) A3 Mr=397. 31, Z=4, Dx=1. 34 g/cm3 , μ= 5. 17 cm-1, F(000) = 832 , R=0. 056 and Rω=0. 060 for 1856 reflections with I≥3σ(Ⅰ).The chemical shifts of the hydrogen atoms bonded to nitrogen atoms N (4) and N (33 are 10. 96 ppm and 7. 57 ppm respectively locating in the lower field. This abnormal situation can be explained by the formation of intramolecular and intermolecular hydrogen bonds. And the X-ray crystallographic analysis demonstrates the existence of the H-bonding six-membered ring in the structure.展开更多
It has recently been shown that chimeric toxin composed of IL2 fused tp PE40, a mutant form of Pseudomonas Exotoxin A devoid of its native cell recognition and binding domain was cytotoxic to IL-2 receptor bearing cel...It has recently been shown that chimeric toxin composed of IL2 fused tp PE40, a mutant form of Pseudomonas Exotoxin A devoid of its native cell recognition and binding domain was cytotoxic to IL-2 receptor bearing cells. We here amplified the gene IL-2(60), which cedes for the N-terminal 1-60 amino acids of human IL-2 by PCR. After that, we fused it to PE40 and the new chimeric protein IL-2(60)-PE40 was expressed in E. coli. SDS-PAGE revealed that IL-2(60)-PE40 chimeric protein accounts for more than 18% of total cell proteins. As the region IL-2 binds with its receptor was defined in the N-terminal residues 8-54 of IL-2, such fusion proteins will have the same activity with IL-2-PE40. Following primany purification, IL-2 (60)-PE40 was shown to be very toxic to IL-2 receptor-positive cells but non measurable effect on the cells lacking IL-2 receptors. Such a structure has not been reported by now. The fusion protein is useful for suppressing the immune response in cases of rejection of allografts and organ transplants and as therapeutic agents for the treatment of IL-2 receptor related diseases scuh as autoimmune disease, ATL(adult T-cell leukemia), et al.展开更多
Ultrasonic speeds have been measured at 298.15 K and 308.15 K for mixtures of formamide ＋ 1 -propanol or 2-propanol. For an equimolar mixture, excess molar compressibility follows the sequence of l-propanol 〉 2-prop...Ultrasonic speeds have been measured at 298.15 K and 308.15 K for mixtures of formamide ＋ 1 -propanol or 2-propanol. For an equimolar mixture, excess molar compressibility follows the sequence of l-propanol 〉 2-propanol. The ultrasonic speed data are correlated by various correlations such as Nomoto＇s relation, van Dael＇s mixing relation and impedance dependence relation, and analyzed in terms of Jacobson＇s free length theory and Schaaffs collision factor theory. Excess isentropic compressibility is calculated from ex- perimental ultrasonic speed data and previously reported excess volume data. The excess molar ultrasonic speed and isentropic compressibility values are fitted to Redlich-Kister polynomial equation. Other proper- ties such as molecular association, available volume, free volume, and intermolecular free length are also calculated. The excess isentropic compressibility data are also interpreted in terms of graph theoretical ap- proach. The calculated isentropic compressibility values are well consistent with the experimental data. It is found that the interaction between formamide and propanol increases when hydroxyl group attached to a carbon atom has more -CH3 groups.展开更多
The possible relationship between diabetes mellitus (DM) and colorectal cancer (CRC), concerning pathophysiological and molecular mechanisms is highlighted in this review. The most recent and complete articles and dev...The possible relationship between diabetes mellitus (DM) and colorectal cancer (CRC), concerning pathophysiological and molecular mechanisms is highlighted in this review. The most recent and complete articles and developments in this particular field were thoroughly reviewed. Common risk factors, such as obesity, sedentary lifestyle, and Western diet between DM and CRC, led to the theory that DM might be a causal agent for CRC development. Various studies have connected type 2 DM and CRC, either proximal or distal, in both sexes. Additionally, chronic insulin treatment has been linked with increased colorectal tumor risk among type 2 diabetic patients. Interestingly, elevated hemoglobin A1c has been proven to be an independent predictor of aggressive clinical behavior in CRC patients. These mechanisms include the insulin-like growth factor-hyperinsulinemia theory and the participation of oncogenic intracellular signaling pathways. Furthermore, it has been proposed that Cox-2 inhibitors might have a role in decreasing the incidence of CRC. Finally, the use of statins to reduce the risk for colon cancer in patients with diabetes has remained controversial. Diabetic patients over 50 should receive counseling regarding their elevated risk for CRC, and screening colonoscopy should be recommended before initiating insulin therapy. However, there are no current guidelines, and this strategy is not yet applicable to some countries, as the corresponding risk would not allow screening colonoscopy to be adopted. There is strong evidence to indicate that DM is a causal agent for CRC development. This conclusion provides new impetus for re-evaluating CRC screening worldwide.展开更多
Iron porphyrins have high activity and selectivity for electrocatalytic CO_(2)reduction reaction(CO_(2)RR)in nonaqueous solutions,but they usually display poor or moderate selectivity for CO_(2)RR in aqueous solutions...Iron porphyrins have high activity and selectivity for electrocatalytic CO_(2)reduction reaction(CO_(2)RR)in nonaqueous solutions,but they usually display poor or moderate selectivity for CO_(2)RR in aqueous solutions because of the competitive hydrogen evolution reaction.Using water as the electrocatalytic reaction solvent is more favored because not only it is cheap,green and abundant but also it can sufficiently provide protons required for CO_(2)RR.Therefore,developing Fe porphyrins as electrocatalysts for efficient and selective CO_(2)RR in aqueous solutions is of both fundamental and practical significance.Herein,we report the design and synthesis of Fe porphyrin 1 with an appended guanidyl group and its electrocatalytic features for CO_(2)RR in both nonaqueous and aqueous solutions.In acetonitrile,Fe porphyrin 1 and its guanidyl-free analogue,tetrakis(3,4,5-trimethoxyphenyl)porphyrin 2,are both efficient for electrocatalytic CO_(2)-to-CO conversion,but the turnover frequency with 1(3.9´10^(5)s^(-1))is one order of magnitude larger than that with 2(1.7´10^(4)s^(-1)),showing the critical role of the appended guanidyl group in improving electrocatalytic CO_(2)RR activity.More importantly,in 0.1 mol L^(-1)KHCO_(3)aqueous solutions,1 showed very high selectivity for electrocatalytic CO_(2)-to-CO conversion with a Faradaic efficiency of 96%,while 2 displayed a Faradaic efficiency of 65%for the CO_(2)-to-CO conversion.This work is of significance to show the effect of appended guanidyl group on improving both activity and selectivity of Fe porphyrins for CO_(2)RR electrocatalysis.展开更多
A leaching experiment was carried out with repacked soil columns in laboratory to stndy the leachingprocess of a red soil derived from sandstone as affected by warions fertilization practices. The treatments wereCK (a...A leaching experiment was carried out with repacked soil columns in laboratory to stndy the leachingprocess of a red soil derived from sandstone as affected by warions fertilization practices. The treatments wereCK (as a control), CaCO_3, CaSO_4, MgCO_3, Ca(H_2PO_4)_2, Urea, KCl, Mnltiple (a mixture of the above-mentioned fertilizers), and KNO_3. The fertilizers were added to the bare surface of the soil columns, andthen the columns were leached with 120 mL deionized water daily through peristaltic pumps over a periodof 92 days. At the end of leaching process, soils were sampled from different depths of the soil profiles, i.e.,0-5 cm, 5-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm. The results showed when applying Ca, Mg, andK to the bare surface of the soil columns, exchangeable Ca￣(2+), Mg￣(2+), and K￣+ in the upper layer of thesoil profile increased correspondingly, with an extent depending mainly on the application rates of Ca, Mg,and K and showing a downward trend. CaCO_3, CaSO_4, MgCO_3, and Ca(H_2PO_4)_2 treatments had scarcelyany effect on movement of exchangeable K￣+, while CaCO_3, and CaSO_4 treatments significantly promotedthe downward movement of exchangeable Mg￣(2+) although these two treatments had no obvious effect onleaching losses of Mg. The fact that under Urea treatment, exchangeable Ca￣(2+) and Mg￣(2+) were higheras compared to CK treatment showed urea could prevent leaching of exchangeable Ca￣(2+) and Mg￣(2+). Theobvious downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was noticed in KCl treatment. In Multipletreatment, the downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was evident, while that of K￣+ was lessevident. Application of KNO_3 strongly promoted the downward movement of exchangeable Ca￣(2+) and Mg￣(2+)in the soil profile.展开更多
Objective To screen forα-glucosidase inhibitor active compounds in the total saponins of Baibiandou(Lablab Semen Album)based on UHPLC-Q-Exactive Orbitrap MS technology and to evaluate its hypoglycemic activity in viv...Objective To screen forα-glucosidase inhibitor active compounds in the total saponins of Baibiandou(Lablab Semen Album)based on UHPLC-Q-Exactive Orbitrap MS technology and to evaluate its hypoglycemic activity in vivo.Methods Acarbose was used as the positive control,and the median inhibitory concentration(IC50)was used as the evaluation index ofα-glucosidase inhibitory activity to establish an in vitroα-glucosidase inhibition model.Further,UHPLC-Q-Exactive Orbitrap MS technology was used to screen and identify the active compounds ofα-glucosidase inhibitors in the total saponins of Baibiandou(Lablab Semen Album)in order to further verify the activity of the main active monomer and to perform homologous modeling and molecular docking of yeast-derivedα-glucosidase and human-derivedα-glucosidase,while the hypoglycemic activity was evaluated in diabetic mice.Results This study successfully identified 15 compounds with potentialα-glucosidase inhibitory activity,including Chikusetsusaponin IVa,from the total saponins of Baibiandou(Lablab Semen Album).Simultaneously,we verified the activity of the main active monomer Chikusetsusaponin IVa,and showed that it has strongα-glucosidase inhibitory activity.Theα-glucosidase inhibitory concentration IC50 was(565.2±1.026)μg/m L,and the IC50 of acarbose,which was lower than the positive control,was(706.6±1.058)μg/m L.The docking energies of Chikusetsusaponin IVa were–6.1 and–7.7 kcal/mol with yeast-derivedα-glucosidase and human-derivedα-glucosidase molecules,respectively.Both showed strong binding activity,and the levels of alanine aminotransaminase(ALT),aspartate aminotransaminase(AST),UREA,Creatinine(CREA),and cholesterol(CHO)were significantly decreased by Chikusetsusaponin IVa(P<0.05).In addition,it could repair damaged liver and pancreas cells of diabetic mice to some extent.Conclusion This study provides a basis for screeningα-glucosidase inhibitors and structural modifications of the total saponins of Baibiandou(Lablab Semen Album).展开更多
It is now widely recognized that chronic hepatitis C (CHC)is associated with insulin resistance(IR)and type 2 diabetes,so can be considered a metabolic disease.IR is most strongly associated with hepatitis C virus(HCV...It is now widely recognized that chronic hepatitis C (CHC)is associated with insulin resistance(IR)and type 2 diabetes,so can be considered a metabolic disease.IR is most strongly associated with hepatitis C virus(HCV)genotype 1,in contrast to hepatic steatosis, which is associated with genotype 3 infection.Apart from the well-described complications of diabetes,IR in CHC predicts faster progression to fibrosis and cirrhosis that may culminate in liver failure and hepatocellular carcinoma.More recently,it has been recognized that IR in CHC predicts a poor response to antiviral therapy. The molecular mechanisms for the association between IR and HCV infection are not well defined.This review will elaborate on the clinical associations between CHC and IR and summarize current knowledge regarding the molecular mechanisms that potentially mediate HCV-associated IR.展开更多
文摘Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles of different forms of atomically-dispersed metals(i.e.,single-atoms and atomic clusters)in photocatalytic reactions remain ambiguous.Herein,we developed an ethylenediamine(EDA)-assisted reduction method to controllably synthesize atomically dispersed Au in the forms of Au single atoms(Au_(SA)),Au clusters(Au_(C)),and a mixed-phase of Au_(SA)and Au_(C)(Au_(SA+C))on CdS.In addition,we elucidate the synergistic effect of Au_(SA)and Au_(C)in enhancing the photocatalytic performance of CdS substrates for simultaneous CO_(2)reduction and aryl alcohol oxidation.Specifically,Au_(SA)can effectively lower the energy barrier for the CO_(2)→*COOH conversion,while Au_(C)can enhance the adsorption of alcohols and reduce the energy barrier for dehydrogenation.As a result,the Au_(SA)and Au_(C)co-loaded CdS show impressive overall photocatalytic CO_(2)conversion performance,achieving remarkable CO and BAD production rates of 4.43 and 4.71 mmol g^(−1)h^(−1),with the selectivities of 93%and 99%,respectively.More importantly,the solar-to-chemical conversion efficiency of Au_(SA+C)/CdS reaches 0.57%,which is over fivefold higher than the typical solar-to-biomass conversion efficiency found in nature(ca.0.1%).This study comprehensively describes the roles of different forms of atomically-dispersed metals and their synergistic effects in photocatalytic reactions,which is anticipated to pave a new avenue in energy and environmental applications.
文摘For the aim of finding new available functional materials, a series of nitrogen heteroatom 2 β naphthylbenzoxazole molecules were designed based on the experiment and theoretical studies of 2 β naphthylbenzoxazole molecule. Geometry optimization of the 2 β naphthylbenzoxazole was carried out by using Hyperchem Molecular Mechanics plus MM+. The planar molecular structure was obtained. The quantum chemistry calculating method PPP SCF CI, which is specially available to treat electron spectrum, was applied to investigate each novel designed molecules. Their electronic structures were analyzed in detail, it shows that total π electron energy decreased linearly with the number of replaced nitrogen. Single nitrogen atom located in benzoxazole ring or naphthalene ring results in contrary changes of level difference of FMO; multiple nitrogen atoms located in different molecular positions will lead to polarization of extremum in the level difference of FMO; and 5 nitrogen heteroatoms reach the culmination. Considering other electronic structure information, some favorable designed molecules were identified.
文摘TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,the presence of alcohol and the temperature were carefully investigated on the crystallization process.The high alkalinity was proved to be highly important for the preservation of the microsphere morphology initially formed,due to the unique intergrown stacking style.An alkali treatment with the aqueous solution of structure-directing agent,organic amine and ammonium salt and subsequent Na+ion-exchange were performed to enhance the catalytic activity of TS-2 microsphere in the cyclohexanone ammoximation reactions,with both the conversion and selectivity higher than 99%.In the continuous reaction,the TS-2 microspheres exhibited to be durable catalyst with potential application in industrial ammoximation processes.
基金The project partially supported by National Natural Science Foundation of China under Grant No. 10471143 and the State 973 Project under Grant No. 2004CB318001 The authors are very grateful to Prof. Hong-Bo Li, Yong Chen, Zhen-Ya Yan, and Zhuo-Sheng Lii for their kind help and valuable suggestions. They also thank Prof. En-Gui Fan and Prof. Chun-Ping Liu for their constructive suggestions about the solutions of Riccati equation.
文摘In this paper, by using symbolic and algebra computation, Chen and Wang＇s multiple R/ccati equations rational expansion method was further extended. Many double soliton-like and other novel combined forms of exact solutions of the （2＋1）-dimensional Breaking soliton equation are derived by using the extended multiple Riccatl equations expansion method.
文摘Objective： To explore the molecular basis of the effects of Gancao （Radix Glycyrrhizae, GC） on inflammation throughthe inhibition of cyclooxygenase 2 （COX-2）. Methods： The Discovery Studio 4.5 System was used to predict thephysicochemical properties of GC molecular compounds. The Ligand Profiler was used to screen for natural GCcomponents that could combine with the COX-2 pharmacophores. The AutoDock Vina 1.1.2 software was used for themolecular docking of the natural GC components with the COX-2 protein. Results： The aromatics were the closest to thenon-steroidal anti-inflammatory drugs in terms of the three properties, namely molecular weight, molecular surface area,and molecular solubility, followed by the flavonoids; whereas the terpenoids/saponins differed most from thenon-steroidal anti-inflammatory drugs in terms of the three properties; and the aliphatics were inconsistent. One hundredand eighteen small molecules were obtained through the pharmacophore screening using GC. The molecular bindingenergy （MBE） results demonstrated that the MBE value of the flavonoids/aromatics, obtained from their binding with theCOX-2 protein, was lower than that obtained from their binding with the substrate, metabolism of arachidonic acid,whereas the MBE value of the aliphatics/terpenoids, obtained from their binding with the COX-2 protein, was higherthan that obtained from their binding with the substrate, arachidonic acid. Finally, further filtration, based on thephysicochemical properties and the molecular binding energies of the small molecules, was carried out. Forty-twonatural GC components, including 35 flavonoid and 7 aromatic constituents, with low binding energies and potentialinhibitory effects on COX-2, were screened. Conclusion： Using the three-step program, pharmacophore screening,molecular docking, and physicochemical properties analysis, we screened out 35 flavonoid molecules and 7 aromaticmolecules, which may be potential COX-2 inhibitors, from GC. Two of the 35 flavonoid molecules （licochalcone A andglabridin） have been confirmed in the laboratory to have inhibitory effects on COX-2. Our findings provide a materialbasis for the development of non-steroidal GC drugs.
基金We thank for the funding support from the Program of Survey of Chinese Medicines of China(No.[2017]66).
文摘Objective To explore the pharmacological mechanism of active saponin compounds of Tuchao Baibiandouren(Lablab Semen Album fried with earth,TCBBDR)in treating type 2 diabetes(T2DM)using UHPLC-Q-Exactive Orbitrap MS and network pharmacology.Methods UHPLC-Q-Exactive Orbitrap MS was used for a qualitative analysis of saponin compounds in TCBBDR.PharmMapper and CTD were used to screen drug active compounds and disease targets,and an active compound-target network was constructed via Cytoscape 3.8.0.Molecular docking was applied with the drug active compounds and key targets using AutoDock Vina 1.1.2,and a trajectory for the molecular dynamics simulation was completed by GROMACS 2019-3.Results Sixteen saponin compounds were identified from TCBBDR,along with 292 saponin compoud targets and 792 T2DM targets.Through Venn analysis of target saponin constituents and T2DM related targets,a total of 91 intersection targets were screened out in the treatment of T2DM with saponin.The mean values of degree,betweenness centrality and closeness centrality were taken as the thresholds to screen out 22 key genes,among which 4 key proteins namely MAPK1,IGF1 EGFR,PIK3R1 were selected in the top 10 key genes.On this basis,the saponin active constituent-target-signaling pathway network was established.The Gene Ontology(GO)enrichment analysis showed that the related biological modules included activity of steroid hormone receptor,steroid binding,and insulin receptor binding,etc.;the related signaling pathways were EGFR,PI3K-Akt and MAPK,etc.;regulating signaling pathways like MAPK could induce the proliferation,inhibition and apoptosis of pancreaticβcells,increase the quantity of pancreaticβcells,improve the functions of pancreaticβcells and stimulate the insulin secretion.Docking experiment analysis showed that all selected saponin compounds could enter the active sites of targets and form 3–14 hydrogen bonds with residues of the active sites.Moreover,van der Waals forces were present between chemical compounds and active sites.By combining the docking binding energy,we determined that the chemical compounds showed strong binding energy to the targets.Conclusion TCBBDR exerts therapeutic effects on diabetes through multi-compound and multi-target collaboration.Specifically,saponin components mediate pathways including inflammatory reaction and signal transduction to treat T2DM by regulating several key proteins that interact with EGFR and a series of signaling pathways related to disease development.
基金Project(51664032)supported by the Regional Foundation of the National Natural Science Foundation of ChinaProject(51474116)supported by the General Program of the National Natural Science Foundation of China+5 种基金Project(U1502271)supported by the Joint Foundation of the NSFC-Yunnan Province,ChinaProject(2014HA003)supported by the Cultivating Plan Program for the Leader in Science and Technology of Yunnan Province,ChinaProject(2014RA4018)supported by the Program for Nonferrous Metals Vacuum Metallurgy Innovation Team of Ministry of Science and Technology,ChinaProject(2016YFC0400404)supported by the National Key Research and Development Program of ChinaProject(51504115)supported by the Youth Program of National Natural Science Foundation of ChinaProject(IRT_17R48)supported by the Program for Innovative Research Team in University of Ministry of Education of China
文摘Structural and electronic properties of PbnAgn(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetallic PbnAgn(n=2–12)clusters were viewed as the initial structures,then,those were calculated by ab initio molecular dynamics(AIMD)to search possible global minimum energy structures of PbnAgn clusters,finally,the ground state structures of PbnAgn(n=2–12)clusters were achieved.According to the structural evolution of lowest energy structures,Ag atoms prefer gather in the central sites while Pb atoms prefer external positions in PbnAgn(n=2–12)clusters,which is in excellent agreement with experimental results from literature and the application in metallurgy.The average binding energies,HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities,chemical hardnessη,HOMO orbits,LUMO orbits and density of states of PbnAgn(n=2–12)clusters were calculated.The results indicate that the values of HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities and chemical hardnessηshow obvious odd-even oscillations when n≤5,PbnAgn(n=2–12)clusters become less chemically stable and show insulator-to-metal transition with the variation of cluster size n,PbnAgn(n≥9)cluster are good candidates to study the properties of PbAg alloys.Those can be well explained by the density of states(DOS)distributions of Pb atoms and Ag atoms between–0.5 Ha and 0.25 Ha in PbnAgn(n=2–12)clusters.
文摘The molecular structure of N, N-bis ( 2-chloroethyl )-N'-isopropyl-N'-phenyl thioureido phosphoramide has been determined by X-ray diffraction method. The crystal(C_14H_23Cl_4N_4OPS) is monoclinic with space group P21/n,α=13. 398(2) , b= 10. 351(4), c= 14. 595(3) A, β= 101. 45(1)°, V=1983(2) A3 Mr=397. 31, Z=4, Dx=1. 34 g/cm3 , μ= 5. 17 cm-1, F(000) = 832 , R=0. 056 and Rω=0. 060 for 1856 reflections with I≥3σ(Ⅰ).The chemical shifts of the hydrogen atoms bonded to nitrogen atoms N (4) and N (33 are 10. 96 ppm and 7. 57 ppm respectively locating in the lower field. This abnormal situation can be explained by the formation of intramolecular and intermolecular hydrogen bonds. And the X-ray crystallographic analysis demonstrates the existence of the H-bonding six-membered ring in the structure.
文摘It has recently been shown that chimeric toxin composed of IL2 fused tp PE40, a mutant form of Pseudomonas Exotoxin A devoid of its native cell recognition and binding domain was cytotoxic to IL-2 receptor bearing cells. We here amplified the gene IL-2(60), which cedes for the N-terminal 1-60 amino acids of human IL-2 by PCR. After that, we fused it to PE40 and the new chimeric protein IL-2(60)-PE40 was expressed in E. coli. SDS-PAGE revealed that IL-2(60)-PE40 chimeric protein accounts for more than 18% of total cell proteins. As the region IL-2 binds with its receptor was defined in the N-terminal residues 8-54 of IL-2, such fusion proteins will have the same activity with IL-2-PE40. Following primany purification, IL-2 (60)-PE40 was shown to be very toxic to IL-2 receptor-positive cells but non measurable effect on the cells lacking IL-2 receptors. Such a structure has not been reported by now. The fusion protein is useful for suppressing the immune response in cases of rejection of allografts and organ transplants and as therapeutic agents for the treatment of IL-2 receptor related diseases scuh as autoimmune disease, ATL(adult T-cell leukemia), et al.
文摘Ultrasonic speeds have been measured at 298.15 K and 308.15 K for mixtures of formamide ＋ 1 -propanol or 2-propanol. For an equimolar mixture, excess molar compressibility follows the sequence of l-propanol 〉 2-propanol. The ultrasonic speed data are correlated by various correlations such as Nomoto＇s relation, van Dael＇s mixing relation and impedance dependence relation, and analyzed in terms of Jacobson＇s free length theory and Schaaffs collision factor theory. Excess isentropic compressibility is calculated from ex- perimental ultrasonic speed data and previously reported excess volume data. The excess molar ultrasonic speed and isentropic compressibility values are fitted to Redlich-Kister polynomial equation. Other proper- ties such as molecular association, available volume, free volume, and intermolecular free length are also calculated. The excess isentropic compressibility data are also interpreted in terms of graph theoretical ap- proach. The calculated isentropic compressibility values are well consistent with the experimental data. It is found that the interaction between formamide and propanol increases when hydroxyl group attached to a carbon atom has more -CH3 groups.
文摘The possible relationship between diabetes mellitus (DM) and colorectal cancer (CRC), concerning pathophysiological and molecular mechanisms is highlighted in this review. The most recent and complete articles and developments in this particular field were thoroughly reviewed. Common risk factors, such as obesity, sedentary lifestyle, and Western diet between DM and CRC, led to the theory that DM might be a causal agent for CRC development. Various studies have connected type 2 DM and CRC, either proximal or distal, in both sexes. Additionally, chronic insulin treatment has been linked with increased colorectal tumor risk among type 2 diabetic patients. Interestingly, elevated hemoglobin A1c has been proven to be an independent predictor of aggressive clinical behavior in CRC patients. These mechanisms include the insulin-like growth factor-hyperinsulinemia theory and the participation of oncogenic intracellular signaling pathways. Furthermore, it has been proposed that Cox-2 inhibitors might have a role in decreasing the incidence of CRC. Finally, the use of statins to reduce the risk for colon cancer in patients with diabetes has remained controversial. Diabetic patients over 50 should receive counseling regarding their elevated risk for CRC, and screening colonoscopy should be recommended before initiating insulin therapy. However, there are no current guidelines, and this strategy is not yet applicable to some countries, as the corresponding risk would not allow screening colonoscopy to be adopted. There is strong evidence to indicate that DM is a causal agent for CRC development. This conclusion provides new impetus for re-evaluating CRC screening worldwide.
文摘Iron porphyrins have high activity and selectivity for electrocatalytic CO_(2)reduction reaction(CO_(2)RR)in nonaqueous solutions,but they usually display poor or moderate selectivity for CO_(2)RR in aqueous solutions because of the competitive hydrogen evolution reaction.Using water as the electrocatalytic reaction solvent is more favored because not only it is cheap,green and abundant but also it can sufficiently provide protons required for CO_(2)RR.Therefore,developing Fe porphyrins as electrocatalysts for efficient and selective CO_(2)RR in aqueous solutions is of both fundamental and practical significance.Herein,we report the design and synthesis of Fe porphyrin 1 with an appended guanidyl group and its electrocatalytic features for CO_(2)RR in both nonaqueous and aqueous solutions.In acetonitrile,Fe porphyrin 1 and its guanidyl-free analogue,tetrakis(3,4,5-trimethoxyphenyl)porphyrin 2,are both efficient for electrocatalytic CO_(2)-to-CO conversion,but the turnover frequency with 1(3.9´10^(5)s^(-1))is one order of magnitude larger than that with 2(1.7´10^(4)s^(-1)),showing the critical role of the appended guanidyl group in improving electrocatalytic CO_(2)RR activity.More importantly,in 0.1 mol L^(-1)KHCO_(3)aqueous solutions,1 showed very high selectivity for electrocatalytic CO_(2)-to-CO conversion with a Faradaic efficiency of 96%,while 2 displayed a Faradaic efficiency of 65%for the CO_(2)-to-CO conversion.This work is of significance to show the effect of appended guanidyl group on improving both activity and selectivity of Fe porphyrins for CO_(2)RR electrocatalysis.
文摘A leaching experiment was carried out with repacked soil columns in laboratory to stndy the leachingprocess of a red soil derived from sandstone as affected by warions fertilization practices. The treatments wereCK (as a control), CaCO_3, CaSO_4, MgCO_3, Ca(H_2PO_4)_2, Urea, KCl, Mnltiple (a mixture of the above-mentioned fertilizers), and KNO_3. The fertilizers were added to the bare surface of the soil columns, andthen the columns were leached with 120 mL deionized water daily through peristaltic pumps over a periodof 92 days. At the end of leaching process, soils were sampled from different depths of the soil profiles, i.e.,0-5 cm, 5-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm. The results showed when applying Ca, Mg, andK to the bare surface of the soil columns, exchangeable Ca￣(2+), Mg￣(2+), and K￣+ in the upper layer of thesoil profile increased correspondingly, with an extent depending mainly on the application rates of Ca, Mg,and K and showing a downward trend. CaCO_3, CaSO_4, MgCO_3, and Ca(H_2PO_4)_2 treatments had scarcelyany effect on movement of exchangeable K￣+, while CaCO_3, and CaSO_4 treatments significantly promotedthe downward movement of exchangeable Mg￣(2+) although these two treatments had no obvious effect onleaching losses of Mg. The fact that under Urea treatment, exchangeable Ca￣(2+) and Mg￣(2+) were higheras compared to CK treatment showed urea could prevent leaching of exchangeable Ca￣(2+) and Mg￣(2+). Theobvious downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was noticed in KCl treatment. In Multipletreatment, the downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was evident, while that of K￣+ was lessevident. Application of KNO_3 strongly promoted the downward movement of exchangeable Ca￣(2+) and Mg￣(2+)in the soil profile.
基金funding support from the Program of the Educational Commission of Hunan Province of China(No.20B418)。
文摘Objective To screen forα-glucosidase inhibitor active compounds in the total saponins of Baibiandou(Lablab Semen Album)based on UHPLC-Q-Exactive Orbitrap MS technology and to evaluate its hypoglycemic activity in vivo.Methods Acarbose was used as the positive control,and the median inhibitory concentration(IC50)was used as the evaluation index ofα-glucosidase inhibitory activity to establish an in vitroα-glucosidase inhibition model.Further,UHPLC-Q-Exactive Orbitrap MS technology was used to screen and identify the active compounds ofα-glucosidase inhibitors in the total saponins of Baibiandou(Lablab Semen Album)in order to further verify the activity of the main active monomer and to perform homologous modeling and molecular docking of yeast-derivedα-glucosidase and human-derivedα-glucosidase,while the hypoglycemic activity was evaluated in diabetic mice.Results This study successfully identified 15 compounds with potentialα-glucosidase inhibitory activity,including Chikusetsusaponin IVa,from the total saponins of Baibiandou(Lablab Semen Album).Simultaneously,we verified the activity of the main active monomer Chikusetsusaponin IVa,and showed that it has strongα-glucosidase inhibitory activity.Theα-glucosidase inhibitory concentration IC50 was(565.2±1.026)μg/m L,and the IC50 of acarbose,which was lower than the positive control,was(706.6±1.058)μg/m L.The docking energies of Chikusetsusaponin IVa were–6.1 and–7.7 kcal/mol with yeast-derivedα-glucosidase and human-derivedα-glucosidase molecules,respectively.Both showed strong binding activity,and the levels of alanine aminotransaminase(ALT),aspartate aminotransaminase(AST),UREA,Creatinine(CREA),and cholesterol(CHO)were significantly decreased by Chikusetsusaponin IVa(P<0.05).In addition,it could repair damaged liver and pancreas cells of diabetic mice to some extent.Conclusion This study provides a basis for screeningα-glucosidase inhibitors and structural modifications of the total saponins of Baibiandou(Lablab Semen Album).
基金Supported by Australian National Health and Medical Research Council and the Robert W Storr Bequest to the University of Sydney
文摘It is now widely recognized that chronic hepatitis C (CHC)is associated with insulin resistance(IR)and type 2 diabetes,so can be considered a metabolic disease.IR is most strongly associated with hepatitis C virus(HCV)genotype 1,in contrast to hepatic steatosis, which is associated with genotype 3 infection.Apart from the well-described complications of diabetes,IR in CHC predicts faster progression to fibrosis and cirrhosis that may culminate in liver failure and hepatocellular carcinoma.More recently,it has been recognized that IR in CHC predicts a poor response to antiviral therapy. The molecular mechanisms for the association between IR and HCV infection are not well defined.This review will elaborate on the clinical associations between CHC and IR and summarize current knowledge regarding the molecular mechanisms that potentially mediate HCV-associated IR.
