Recent years have witnessed significant advances in the development of novel techniques and methodologies for identifying active ingredients in traditional Chinese medicine(TCM),substantially advancing research and de...Recent years have witnessed significant advances in the development of novel techniques and methodologies for identifying active ingredients in traditional Chinese medicine(TCM),substantially advancing research and development efforts.Spectrum-effect correlation analysis,affinity ultrafiltration,high-content screening(HCS)imaging,and cell membrane chromatography(CMC)have emerged as essential tools,effectively linking TCM chemical constituents to their biological effects,thereby enabling efficient active ingredient screening.Additionally,molecular interaction analysis provides deeper insights into TCM-biomolecule interaction mechanisms,enhancing understanding of its therapeutic potential.Computer-aided techniques facilitate TCM active ingredient identification,optimizing the screening process for efficiency and cost-effectiveness.Molecular probe technology,as an emerging methodology,enables precise and rapid screening for novel therapeutic drug discovery.Ongoing technological advancement in this field indicates promising future developments,potentially leading to more effective and targeted TCM-based therapies.展开更多
This paper systematically categorizes the primary composition of star anise(Illicium verum),including volatile oils,flavonoids,phenolic acids,and sesquiterpene lactones,and further analyzes the pharmacological activit...This paper systematically categorizes the primary composition of star anise(Illicium verum),including volatile oils,flavonoids,phenolic acids,and sesquiterpene lactones,and further analyzes the pharmacological activities,such as antibacterial,analgesic,anti-inflammatory,and antioxidant effects.Additionally,it summarizes key aspects of extraction techniques,analytical methods,and fresh material processing technologies.The objective is to provide a robust foundation for enhancing research methods and technological standards related to star anise,thereby improving resource utilization efficiency and facilitating its industrial applications.展开更多
The catalytic conversion of CO_(2) to fuels or chemicals is considered to be an effective pathway to mitigate the greenhouse effect. To develop new types of efficient and durable catalysts, it is critical to identify ...The catalytic conversion of CO_(2) to fuels or chemicals is considered to be an effective pathway to mitigate the greenhouse effect. To develop new types of efficient and durable catalysts, it is critical to identify the catalytic active sites, surface intermediates, and reaction mechanisms to reveal the relationship between the active sites and catalytic performance. However, the structure of a heterogeneous catalyst usually dynamically changes during reaction, bringing a great challenge for the identification of catalytic active sites and reaction pathways. Therefore, in-situ/operando techniques have been employed to real-time monitor the dynamic evolution of the structure of active sites under actual reaction conditions to precisely build the structure–function relationship. Here, we review the recent progress in the application of various in-situ/operando techniques in identifying active sites for catalytic conversion of CO_(2) over heterogeneous catalysts. We systematically summarize the applications of various optical and X-ray spectroscopy techniques, including Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS), in identifying active sites and determining reaction mechanisms of the CO_(2) thermochemical conversion with hydrogen and light alkanes over heterogeneous catalysts. Finally, we discuss challenges and opportunities for the development of in-situ characterization in the future to further enlarge the capability of these powerful techniques.展开更多
The component synthesis active vibration suppression method （CSVS） can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according...The component synthesis active vibration suppression method （CSVS） can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according to certain rules along the time axis. The synthesized command can suppress the arbitrary unwanted vibration harmonic while achieving the desired rigid body motion. The number of the components increases rapidly when the number of harmonic vibration is growing. In this article, the CSVS based on zero-placement technique is used to construct the synthesized command to suppress the multi-harmonics simultaneously in the discrete domain. The nature of zero-placement method is to put enough zeros to cancel system poles at necessary points. The designed synthesized command has equal time intervals between each component and which is much easier to be implemented. Using this method, the number of components increases linearly with the increasing of the number of being suppressed harmonics. For the spacecraft with flexible appendages, CSVS based on zero-placement is used to design the time optimal large angle maneuver control strategy. Simulations have verified the validity and superiority of the proposed approach.展开更多
[Objective] This study aimed to analyze the expression, purification and insecticidal activity of Cry1Ac without helix α-1 of domain I in E. coli. [Method] Plasmid of B. thuringiensis HD-1 was used as the template fo...[Objective] This study aimed to analyze the expression, purification and insecticidal activity of Cry1Ac without helix α-1 of domain I in E. coli. [Method] Plasmid of B. thuringiensis HD-1 was used as the template for amplification of Cry1Ac gene, which was linked with pET28a vector to construct the recombinant plasmid. After transformation and IPTG induction, expression of target protein was detected by using SDS-PAGE method. Target protein was extracted and coated on the surface of feed for H. armigera to determine the insecticidal activity. [Result] Cry1Acdela1 gene could normally express the target protein in E. coli. However, the target protein existed in the form of inclusion body. Results of bioassay analysis showed that under the same concentration, fatality rate of activated Cry1Ac toxin reached above 75%, while that of Cry1Acdelα1 was only about 10%. [Conclusion] E. coli-expressed Cry1Acdelα1 had no insecticidal activity against H. armigera.展开更多
This paper presents four teaching techniques of activating the textbook for intensive reading which include:injecting contemporary elements into the text,relating the text to students' life,questioning about the t...This paper presents four teaching techniques of activating the textbook for intensive reading which include:injecting contemporary elements into the text,relating the text to students' life,questioning about the text challengingly and ingeniously,and spicing up the text.展开更多
Harmine,a beta-carboline alkaloid,is widely distributed in the plants,marine creatures,insects, mammalians as well as in human tissues and body fluids.Harmine was originally isolated from seeds of Peganum harmal in 18...Harmine,a beta-carboline alkaloid,is widely distributed in the plants,marine creatures,insects, mammalians as well as in human tissues and body fluids.Harmine was originally isolated from seeds of Peganum harmal in 1847 having a core indole structure and a pyridine ring.Harmine has various types of pharmacological activities such as antimicrobial,antifungal,antitumor,cytotoxic, antiplasmodial,antioxidaant,antimutagenic,antigenotoxic and hallucinogenic properties.It acts on gamma-aminobutyric acid type A and monoamine oxidase A or B receptor,enhances insulin sensitivity and also produces vasorelaxant effect.Harmine prevents bone loss by suppressing osteoclastogenesis.The current review gives an overview on pharmacological activity and analytical techniques of harmine,which may be useful for researcheres to explore the hidden potential of harmine and and will also help in developing new drugs for the treatment of various diseases.展开更多
Samples of two crop seeds (corn and sesame) grown on different contaminated soil sources were collected and prepared for neutron activation analysis. Soil contamination sources were organic waste compost applied to s...Samples of two crop seeds (corn and sesame) grown on different contaminated soil sources were collected and prepared for neutron activation analysis. Soil contamination sources were organic waste compost applied to soil amendments namely, sewage sludge(Bs) and municipal solid waste (MSW) at 4%, 6% and 8% respectively. The non destructive NAA technique was used to determine some trace elements accumulation in plant seeds. Results revealed that increasing rate of tested organic waste resulted in dramatic increase in tested heavy metals levels in seeds(i.e., Fe, Zn, Co, Cr, Sc and Hg). Sesame seeds showed higher affinity to accumulate trace elements than corn grains in most tested elements. Moreover, MSW addition enhanced the accumulation of tested metals in seeds more than Bs compost.展开更多
Electrocatalytic oxygen reduction reaction(ORR)is one of the most important reactions in electrochemical energy technologies such as fuel cells and metal–O2/air batteries,etc.However,the essential catalysts to overco...Electrocatalytic oxygen reduction reaction(ORR)is one of the most important reactions in electrochemical energy technologies such as fuel cells and metal–O2/air batteries,etc.However,the essential catalysts to overcome its slow reaction kinetic always undergo a complex dynamic evolution in the actual catalytic process,and the concomitant intermediates and catalytic products also occur continuous conversion and reconstruction.This makes them difficult to be accurately captured,making the identification of ORR active sites and the elucidation of ORR mechanisms difficult.Thus,it is necessary to use extensive in-situ characterization techniques to proceed the real-time monitoring of the catalyst structure and the evolution state of intermediates and products during ORR.This work reviews the major advances in the use of various in-situ techniques to characterize the catalytic processes of various catalysts.Specifically,the catalyst structure evolutions revealed directly by in-situ techniques are systematically summarized,such as phase,valence,electronic transfer,coordination,and spin states varies.In-situ revelation of intermediate adsorption/desorption behavior,and the real-time monitoring of the product nucleation,growth,and reconstruction evolution are equally emphasized in the discussion.Other interference factors,as well as in-situ signal assignment with the aid of theoretical calculations,are also covered.Finally,some major challenges and prospects of in-situ techniques for future catalysts research in the ORR process are proposed.展开更多
The titanium coatings were prepared on Al_(2)O_(3) balls by mechanical coating technique (MCT),and then the coatings were oxidized to titanium oxides(TiO_(2)) films at 300-600 ℃.The effects of different milling time ...The titanium coatings were prepared on Al_(2)O_(3) balls by mechanical coating technique (MCT),and then the coatings were oxidized to titanium oxides(TiO_(2)) films at 300-600 ℃.The effects of different milling time and oxidation temperature on thickness of films were studied.The composition and microstructure of the films were analyzed by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS).The results show that the thickest coatings with an average thickness of 20 μm were obtained at the milling time of 15 h.In addition,with the increase of the oxidation temperature,the oxidation of the film is increased.When the milling time is 15 h,the oxidation temperature is 500 ℃,and the addition of photocatalyst is 1 g/mL.The films have the best photocatalytic performance when the degradation rate of methyl orange solution reaches the maximum value of 74.9 %,and the films have a good reusability.展开更多
This report reviews the characteristics of JS399-19, a novel cyanoacrylate fungicide. JS399-19 strongly inhibits the mycelial growth of the fungal plant pathogens of the genus Fusarium and exhibits great potential in ...This report reviews the characteristics of JS399-19, a novel cyanoacrylate fungicide. JS399-19 strongly inhibits the mycelial growth of the fungal plant pathogens of the genus Fusarium and exhibits great potential in controlling Fusarium head blight （FHB） on wheat and other cereals. The mode of action of JS399-19 is evidently different from that of benzimidazole （for example, carbendazim） and other sort of fungicides, making it a possible replacement for carbendazim in China to manage carbendazim-resistant subpopulations of Fusarium graminearum and F. asiaticum. JS399-t9 has excellent protective and curative activity against these pathogens. Incorrect use of this fungicide, however, is likely to select for resistance. Among JS399-19-resistant mutants of F. asiaticum induced in the laboratory, the resistant level of mutants was high and the phenotype of resistance against JS399-19 was conferred by a major gene by genetic analysis. The fitness of laboratory-induced JS399-19-resistant mutants of F. asiaticum was nearly equal to that of their parents. JS399-19 lacks cross resistance with other sort fungicides. To control FHB with JS399-19 and to delay the development of the fungicide-resistance, farmers should use tank mixtures containing JS399-19 and carbendazim, metconazole, tebuconazole, or prothioconazole.展开更多
A method combining the pseudo-dynamic approach and discretization technique is carried out for computing the active earth pressure.Instead of using a presupposed failure mechanism,discretization technique is introduce...A method combining the pseudo-dynamic approach and discretization technique is carried out for computing the active earth pressure.Instead of using a presupposed failure mechanism,discretization technique is introduced to generate the potential failure surface,which is applicable to the case that soil strength parameters have spatial variability.For the purpose of analyzing the effect of earthquake,pseudo-dynamic approach is adopted to introduce the seismic forces,which can take into account the dynamic properties of seismic acceleration.A new type of micro-element is used to calculate the rate of work of external forces and the rate of internal energy dissipation.The analytical expression of seismic active earth pressure coefficient is deduced in the light of upper bound theorem and the corresponding upper bound solutions are obtained through numerical optimization.The method is validated by comparing the results of this paper with those reported in literatures.The parametric analysis is finally presented to further expound the effect of diverse parameters on active earth pressure under non-uniform soil.展开更多
Based on Kohler’s ternary solution model and Miedemaa’s model for calculating the heats of formation-△Hij of binary Systems, the integral equation has ben established for calculating the activity coefficients in te...Based on Kohler’s ternary solution model and Miedemaa’s model for calculating the heats of formation-△Hij of binary Systems, the integral equation has ben established for calculating the activity coefficients in ternarysolution. With the equation, the activity coefficients in Ti-15-3 melt have been calculated. The results show that allof components’ activity coefficients are less than 1, in other wolds, compared with ideal solution, all components takeon a negative deviation. At 2000K, the activity coefficients in Ti-15-3 melt are shown as: about 0.9 for Ti, about0.85 for V, about 0. 1 for Al, aboaut 0.5 for Cr and about 0.23 for Sn. me addition of V lowers the activity coefficient of Ti, but raise the ones of Al, Cr and Sn. These results can be directly used to calculate the evaporation loss ofAl, Cr and Sn during the ISM(Induction Skull Melting) process and at the same time estimate the reactivity betweenTi-15-3 melt and refractory during the cast production.展开更多
Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart di...Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.展开更多
Dear Editor, The 2015-2016 outbreak of Zika virus （ZIKV） fever, first reported in Brazil during early 2015 （Zanluca et al., 2015）, has infected millions of people and is a global public health concern. ZIKV infect...Dear Editor, The 2015-2016 outbreak of Zika virus （ZIKV） fever, first reported in Brazil during early 2015 （Zanluca et al., 2015）, has infected millions of people and is a global public health concern. ZIKV infections are associated with fetal microcephaly, as well as neurological complications in humans. The virus can be shed in the semen and vaginal secretions of humans, leading to sexual transmission, and unexpectedly ZIKV infections cause severe damage to the male reproductive organs in male mice （Govero et al., 2016; Ma et al., 2016）.展开更多
Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was des...Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.展开更多
To synthesize a series of 3-, 4-, and/or 11-trihydroxy modified bergenin derivatives and evaluated their cytotoxic activity in vitro. The phenolic hydroxyl groups of bergenin were protected by benzyl groups with benzy...To synthesize a series of 3-, 4-, and/or 11-trihydroxy modified bergenin derivatives and evaluated their cytotoxic activity in vitro. The phenolic hydroxyl groups of bergenin were protected by benzyl groups with benzyl bromide. Treatment of dibenzyl bergenin with the corresponding acid in the presence of EDC·HCl and DMAP in CH2Cl2, followed by hydrogenation over Pd/C catalysts, afforded derivatives of bergenin esters. All of the target compounds were identified by IR, MS, and 1H NMR. Twenty-six novel and three known derivatives of bergenin esters were synthesized. Their cytotoxicity values were evaluated by the MTT assay on the inhibition of DU-145 and BGC-823 cells in vitro. Several triply-substituted(3a, 4a, 5a, 6a, 7a) and doublysubstituted(8b, 9b) bergenin derivatives exhibited higher cytotoxic activity than bergenin. The result showed that the size of substituents and the lipophilicity of the bergenin esters displayed an important role on their cytotoxic activity.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
Three new rare cyclopiane diterpenes(1-3),together with thirteen known compounds(4-16),were isolated and identified from a sea sediment-derived fungus Penicillium sp.TJ403-2.The planar and relative structures of compo...Three new rare cyclopiane diterpenes(1-3),together with thirteen known compounds(4-16),were isolated and identified from a sea sediment-derived fungus Penicillium sp.TJ403-2.The planar and relative structures of compounds 1-3 were elucidated by HRESIMS,one-and two-dimensional NMR analyses,and their absolute configurations were further established by X-ray crystallography experiment.Compounds 1-3 were evaluated for the anti-inflammatory activity against LPS-induced NO production,and compound 1 showed notable inhibitory potency with an IC50 value of2.19±0.25μmol/L,which was three fold lower than the positive control indomethacin(IC50=8.76±0.92μmol/L).Further Western blot and immunofluorescence experiments demonstrated its mechanism of action to be that 1 inhibited the NF-κB-activated pathway,highlighting it as a promising starting point for the development of new anti-inflammatory agents.展开更多
The title compound （E）-4-tert-butyl-N-（2,4-dichlorobenzylidene）-5-（1,2,4-triazol-1-yl）-thiazol-2-amine was synthesized by the reaction of 4-tert-butyl-5-（1,2,4-triazol-1-yl）-thiazol-2-amine with 2,4-dichlorobe...The title compound （E）-4-tert-butyl-N-（2,4-dichlorobenzylidene）-5-（1,2,4-triazol-1-yl）-thiazol-2-amine was synthesized by the reaction of 4-tert-butyl-5-（1,2,4-triazol-1-yl）-thiazol-2-amine with 2,4-dichlorobenzaldehyde, and its crystal structure was determined by singlecrystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.9748（4）, b = 10.1803（5）, c = 11.4603（6）, α = 102.882（1）, β = 100.253（1）, γ = 104.457（1）°, V = 850.95（7）3, Z = 2, F（000） = 392, C16H15Cl2N5S, Mr = 380.29, Dc = 1.484 g/cm3, S = 1.095, μ = 0.512 mm-1, the final R = 0.0301 and wR = 0.0965 for 3334 observed reflections （I 〉 2σ（I））. The preliminary antitumor activity shows that for the title compound the IC50 of Hela is 0.175 μmol/mL and that of Bel7402 is 0.156 μmol/mL.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 22175078, 52373287, 82404846, and 22467002)the Natural Science Foundation of Jiangsu Province of China (No. BK20241597)the Fundamental Research Funds for the Central Universities (No. 2632024TD05)
文摘Recent years have witnessed significant advances in the development of novel techniques and methodologies for identifying active ingredients in traditional Chinese medicine(TCM),substantially advancing research and development efforts.Spectrum-effect correlation analysis,affinity ultrafiltration,high-content screening(HCS)imaging,and cell membrane chromatography(CMC)have emerged as essential tools,effectively linking TCM chemical constituents to their biological effects,thereby enabling efficient active ingredient screening.Additionally,molecular interaction analysis provides deeper insights into TCM-biomolecule interaction mechanisms,enhancing understanding of its therapeutic potential.Computer-aided techniques facilitate TCM active ingredient identification,optimizing the screening process for efficiency and cost-effectiveness.Molecular probe technology,as an emerging methodology,enables precise and rapid screening for novel therapeutic drug discovery.Ongoing technological advancement in this field indicates promising future developments,potentially leading to more effective and targeted TCM-based therapies.
基金Supported by Project of Guangxi Zhuang Autonomous Region Administration of Traditional Chinese Medicine(GXZYA20230001)Research Fund Project of Guangxi Zhuang Autonomous Region Medicinal Botanical Garden(202304).
文摘This paper systematically categorizes the primary composition of star anise(Illicium verum),including volatile oils,flavonoids,phenolic acids,and sesquiterpene lactones,and further analyzes the pharmacological activities,such as antibacterial,analgesic,anti-inflammatory,and antioxidant effects.Additionally,it summarizes key aspects of extraction techniques,analytical methods,and fresh material processing technologies.The objective is to provide a robust foundation for enhancing research methods and technological standards related to star anise,thereby improving resource utilization efficiency and facilitating its industrial applications.
基金Authors acknowledge the financial support from the National Natural Science Foundation of China(NSFC)under Grant No.21978148 and 21808120.
文摘The catalytic conversion of CO_(2) to fuels or chemicals is considered to be an effective pathway to mitigate the greenhouse effect. To develop new types of efficient and durable catalysts, it is critical to identify the catalytic active sites, surface intermediates, and reaction mechanisms to reveal the relationship between the active sites and catalytic performance. However, the structure of a heterogeneous catalyst usually dynamically changes during reaction, bringing a great challenge for the identification of catalytic active sites and reaction pathways. Therefore, in-situ/operando techniques have been employed to real-time monitor the dynamic evolution of the structure of active sites under actual reaction conditions to precisely build the structure–function relationship. Here, we review the recent progress in the application of various in-situ/operando techniques in identifying active sites for catalytic conversion of CO_(2) over heterogeneous catalysts. We systematically summarize the applications of various optical and X-ray spectroscopy techniques, including Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS), in identifying active sites and determining reaction mechanisms of the CO_(2) thermochemical conversion with hydrogen and light alkanes over heterogeneous catalysts. Finally, we discuss challenges and opportunities for the development of in-situ characterization in the future to further enlarge the capability of these powerful techniques.
文摘The component synthesis active vibration suppression method （CSVS） can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according to certain rules along the time axis. The synthesized command can suppress the arbitrary unwanted vibration harmonic while achieving the desired rigid body motion. The number of the components increases rapidly when the number of harmonic vibration is growing. In this article, the CSVS based on zero-placement technique is used to construct the synthesized command to suppress the multi-harmonics simultaneously in the discrete domain. The nature of zero-placement method is to put enough zeros to cancel system poles at necessary points. The designed synthesized command has equal time intervals between each component and which is much easier to be implemented. Using this method, the number of components increases linearly with the increasing of the number of being suppressed harmonics. For the spacecraft with flexible appendages, CSVS based on zero-placement is used to design the time optimal large angle maneuver control strategy. Simulations have verified the validity and superiority of the proposed approach.
基金Supported by Beijing Natural Science Foundation(50920075112009)~~
文摘[Objective] This study aimed to analyze the expression, purification and insecticidal activity of Cry1Ac without helix α-1 of domain I in E. coli. [Method] Plasmid of B. thuringiensis HD-1 was used as the template for amplification of Cry1Ac gene, which was linked with pET28a vector to construct the recombinant plasmid. After transformation and IPTG induction, expression of target protein was detected by using SDS-PAGE method. Target protein was extracted and coated on the surface of feed for H. armigera to determine the insecticidal activity. [Result] Cry1Acdela1 gene could normally express the target protein in E. coli. However, the target protein existed in the form of inclusion body. Results of bioassay analysis showed that under the same concentration, fatality rate of activated Cry1Ac toxin reached above 75%, while that of Cry1Acdelα1 was only about 10%. [Conclusion] E. coli-expressed Cry1Acdelα1 had no insecticidal activity against H. armigera.
文摘This paper presents four teaching techniques of activating the textbook for intensive reading which include:injecting contemporary elements into the text,relating the text to students' life,questioning about the text challengingly and ingeniously,and spicing up the text.
文摘Harmine,a beta-carboline alkaloid,is widely distributed in the plants,marine creatures,insects, mammalians as well as in human tissues and body fluids.Harmine was originally isolated from seeds of Peganum harmal in 1847 having a core indole structure and a pyridine ring.Harmine has various types of pharmacological activities such as antimicrobial,antifungal,antitumor,cytotoxic, antiplasmodial,antioxidaant,antimutagenic,antigenotoxic and hallucinogenic properties.It acts on gamma-aminobutyric acid type A and monoamine oxidase A or B receptor,enhances insulin sensitivity and also produces vasorelaxant effect.Harmine prevents bone loss by suppressing osteoclastogenesis.The current review gives an overview on pharmacological activity and analytical techniques of harmine,which may be useful for researcheres to explore the hidden potential of harmine and and will also help in developing new drugs for the treatment of various diseases.
文摘Samples of two crop seeds (corn and sesame) grown on different contaminated soil sources were collected and prepared for neutron activation analysis. Soil contamination sources were organic waste compost applied to soil amendments namely, sewage sludge(Bs) and municipal solid waste (MSW) at 4%, 6% and 8% respectively. The non destructive NAA technique was used to determine some trace elements accumulation in plant seeds. Results revealed that increasing rate of tested organic waste resulted in dramatic increase in tested heavy metals levels in seeds(i.e., Fe, Zn, Co, Cr, Sc and Hg). Sesame seeds showed higher affinity to accumulate trace elements than corn grains in most tested elements. Moreover, MSW addition enhanced the accumulation of tested metals in seeds more than Bs compost.
基金the National Natural Science Foundation of China(No.52072256)Shanxi Science and Technology Major Project(No.20201101016)+1 种基金Key R&D program of Shanxi Province(No.202102030201006)Research Project Supported by Shanxi Scholarship Council of China(HGKY2019031).
文摘Electrocatalytic oxygen reduction reaction(ORR)is one of the most important reactions in electrochemical energy technologies such as fuel cells and metal–O2/air batteries,etc.However,the essential catalysts to overcome its slow reaction kinetic always undergo a complex dynamic evolution in the actual catalytic process,and the concomitant intermediates and catalytic products also occur continuous conversion and reconstruction.This makes them difficult to be accurately captured,making the identification of ORR active sites and the elucidation of ORR mechanisms difficult.Thus,it is necessary to use extensive in-situ characterization techniques to proceed the real-time monitoring of the catalyst structure and the evolution state of intermediates and products during ORR.This work reviews the major advances in the use of various in-situ techniques to characterize the catalytic processes of various catalysts.Specifically,the catalyst structure evolutions revealed directly by in-situ techniques are systematically summarized,such as phase,valence,electronic transfer,coordination,and spin states varies.In-situ revelation of intermediate adsorption/desorption behavior,and the real-time monitoring of the product nucleation,growth,and reconstruction evolution are equally emphasized in the discussion.Other interference factors,as well as in-situ signal assignment with the aid of theoretical calculations,are also covered.Finally,some major challenges and prospects of in-situ techniques for future catalysts research in the ORR process are proposed.
基金Funded by University-level Project of Jincheng College of Sichuan University(No.2020jcky0014)。
文摘The titanium coatings were prepared on Al_(2)O_(3) balls by mechanical coating technique (MCT),and then the coatings were oxidized to titanium oxides(TiO_(2)) films at 300-600 ℃.The effects of different milling time and oxidation temperature on thickness of films were studied.The composition and microstructure of the films were analyzed by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS).The results show that the thickest coatings with an average thickness of 20 μm were obtained at the milling time of 15 h.In addition,with the increase of the oxidation temperature,the oxidation of the film is increased.When the milling time is 15 h,the oxidation temperature is 500 ℃,and the addition of photocatalyst is 1 g/mL.The films have the best photocatalytic performance when the degradation rate of methyl orange solution reaches the maximum value of 74.9 %,and the films have a good reusability.
基金sponsored by the National Natural Science Foundation of China (30971891)the Natural Science Foundation of Jiangsu Province, China(BK2008337)the Anhui Provincial Natural Sci-ence Foundation,China (10040606Q26)
文摘This report reviews the characteristics of JS399-19, a novel cyanoacrylate fungicide. JS399-19 strongly inhibits the mycelial growth of the fungal plant pathogens of the genus Fusarium and exhibits great potential in controlling Fusarium head blight （FHB） on wheat and other cereals. The mode of action of JS399-19 is evidently different from that of benzimidazole （for example, carbendazim） and other sort of fungicides, making it a possible replacement for carbendazim in China to manage carbendazim-resistant subpopulations of Fusarium graminearum and F. asiaticum. JS399-t9 has excellent protective and curative activity against these pathogens. Incorrect use of this fungicide, however, is likely to select for resistance. Among JS399-19-resistant mutants of F. asiaticum induced in the laboratory, the resistant level of mutants was high and the phenotype of resistance against JS399-19 was conferred by a major gene by genetic analysis. The fitness of laboratory-induced JS399-19-resistant mutants of F. asiaticum was nearly equal to that of their parents. JS399-19 lacks cross resistance with other sort fungicides. To control FHB with JS399-19 and to delay the development of the fungicide-resistance, farmers should use tank mixtures containing JS399-19 and carbendazim, metconazole, tebuconazole, or prothioconazole.
基金Projects(51908557,51378510)supported by the National Natural Science Foundation of China。
文摘A method combining the pseudo-dynamic approach and discretization technique is carried out for computing the active earth pressure.Instead of using a presupposed failure mechanism,discretization technique is introduced to generate the potential failure surface,which is applicable to the case that soil strength parameters have spatial variability.For the purpose of analyzing the effect of earthquake,pseudo-dynamic approach is adopted to introduce the seismic forces,which can take into account the dynamic properties of seismic acceleration.A new type of micro-element is used to calculate the rate of work of external forces and the rate of internal energy dissipation.The analytical expression of seismic active earth pressure coefficient is deduced in the light of upper bound theorem and the corresponding upper bound solutions are obtained through numerical optimization.The method is validated by comparing the results of this paper with those reported in literatures.The parametric analysis is finally presented to further expound the effect of diverse parameters on active earth pressure under non-uniform soil.
文摘Based on Kohler’s ternary solution model and Miedemaa’s model for calculating the heats of formation-△Hij of binary Systems, the integral equation has ben established for calculating the activity coefficients in ternarysolution. With the equation, the activity coefficients in Ti-15-3 melt have been calculated. The results show that allof components’ activity coefficients are less than 1, in other wolds, compared with ideal solution, all components takeon a negative deviation. At 2000K, the activity coefficients in Ti-15-3 melt are shown as: about 0.9 for Ti, about0.85 for V, about 0. 1 for Al, aboaut 0.5 for Cr and about 0.23 for Sn. me addition of V lowers the activity coefficient of Ti, but raise the ones of Al, Cr and Sn. These results can be directly used to calculate the evaporation loss ofAl, Cr and Sn during the ISM(Induction Skull Melting) process and at the same time estimate the reactivity betweenTi-15-3 melt and refractory during the cast production.
文摘Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.
文摘Dear Editor, The 2015-2016 outbreak of Zika virus （ZIKV） fever, first reported in Brazil during early 2015 （Zanluca et al., 2015）, has infected millions of people and is a global public health concern. ZIKV infections are associated with fetal microcephaly, as well as neurological complications in humans. The virus can be shed in the semen and vaginal secretions of humans, leading to sexual transmission, and unexpectedly ZIKV infections cause severe damage to the male reproductive organs in male mice （Govero et al., 2016; Ma et al., 2016）.
文摘Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.
基金supported by the Natural Science Foundation of China(Nos.81274064 and 81373956)the National Fund for Fostering Talents of Basic Science(NFFTBS)(No.J1030830)the Science and Technology Supporting Project of Xinjiang(No.201291160)
文摘To synthesize a series of 3-, 4-, and/or 11-trihydroxy modified bergenin derivatives and evaluated their cytotoxic activity in vitro. The phenolic hydroxyl groups of bergenin were protected by benzyl groups with benzyl bromide. Treatment of dibenzyl bergenin with the corresponding acid in the presence of EDC·HCl and DMAP in CH2Cl2, followed by hydrogenation over Pd/C catalysts, afforded derivatives of bergenin esters. All of the target compounds were identified by IR, MS, and 1H NMR. Twenty-six novel and three known derivatives of bergenin esters were synthesized. Their cytotoxicity values were evaluated by the MTT assay on the inhibition of DU-145 and BGC-823 cells in vitro. Several triply-substituted(3a, 4a, 5a, 6a, 7a) and doublysubstituted(8b, 9b) bergenin derivatives exhibited higher cytotoxic activity than bergenin. The result showed that the size of substituents and the lipophilicity of the bergenin esters displayed an important role on their cytotoxic activity.
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financially supported by the Program for Changjiang Scholars of Ministry of Education of the People’s Republic of China (No.T2016088)the National Natural Science Foundation for Distinguished Young Scholars (No.81725021)+1 种基金the Innovative Research Groups of the National Natural Science Foundation of China (No.81721005)the National Natural Science Foundation of China (Nos.81573316 and 21702067)
文摘Three new rare cyclopiane diterpenes(1-3),together with thirteen known compounds(4-16),were isolated and identified from a sea sediment-derived fungus Penicillium sp.TJ403-2.The planar and relative structures of compounds 1-3 were elucidated by HRESIMS,one-and two-dimensional NMR analyses,and their absolute configurations were further established by X-ray crystallography experiment.Compounds 1-3 were evaluated for the anti-inflammatory activity against LPS-induced NO production,and compound 1 showed notable inhibitory potency with an IC50 value of2.19±0.25μmol/L,which was three fold lower than the positive control indomethacin(IC50=8.76±0.92μmol/L).Further Western blot and immunofluorescence experiments demonstrated its mechanism of action to be that 1 inhibited the NF-κB-activated pathway,highlighting it as a promising starting point for the development of new anti-inflammatory agents.
基金Supported by the Natural Science Foundation of Hunan Province (No. 07JJ302)
文摘The title compound （E）-4-tert-butyl-N-（2,4-dichlorobenzylidene）-5-（1,2,4-triazol-1-yl）-thiazol-2-amine was synthesized by the reaction of 4-tert-butyl-5-（1,2,4-triazol-1-yl）-thiazol-2-amine with 2,4-dichlorobenzaldehyde, and its crystal structure was determined by singlecrystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.9748（4）, b = 10.1803（5）, c = 11.4603（6）, α = 102.882（1）, β = 100.253（1）, γ = 104.457（1）°, V = 850.95（7）3, Z = 2, F（000） = 392, C16H15Cl2N5S, Mr = 380.29, Dc = 1.484 g/cm3, S = 1.095, μ = 0.512 mm-1, the final R = 0.0301 and wR = 0.0965 for 3334 observed reflections （I 〉 2σ（I））. The preliminary antitumor activity shows that for the title compound the IC50 of Hela is 0.175 μmol/mL and that of Bel7402 is 0.156 μmol/mL.
