[Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavo...[Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavonoid glycosides were isolated and purified from the ethanol alcoholic extract of the roots of Liliaceae plant Chlorophytum comosum by silica gel column chromatography,macroporous resin column chromatography,Sephadex LH-20,and reverse column chromatography(ODS).The inhibitory activity of flavonoid glycosides on human nasopharyngeal carcinoma cells was analyzed by CCK-8 method,and the potential mechanism was preliminarily analyzed by molecular docking.[Results]Two flavonoid glycosides were identified as isovitexin 2″-0-rhamnoside and 7-2″-di-O-β-glucopyranosylisovitexin.Two flavonoid glycosides showed promising inhibitory effect on human nasopharyngeal carcinoma cell line 5-8F,with IC_(50) values of 24.8 and 27.5μmol/L,respectively.Molecular docking results showed that the potential targets of two flavonoid glycosides include CyclinD1,Bcl-2β-Catenin,ILK,TGF-β,in addition,two glycosides showed higher predicted binding affinity towards CyclinD1,which verifies the cytotoxicity of the two compounds on human nasopharyngeal carcinoma cell line 5-8F in vitro.[Conclusions]Two flavonoid glycosides are the active molecules in Chlorophytum comosum that can inhibit the proliferation of human nasopharyngeal carcinoma cells,and have the potential to be used in the research and development of anti nasopharyngeal carcinoma drugs.展开更多
A tetrad field that is homogeneous and anisotropic which contains two unknown functions A（t） and B（t） of cosmic time is applied to the field equations of f（T）, where T is the torsion scalar, T = T~μ_（νρ）S_...A tetrad field that is homogeneous and anisotropic which contains two unknown functions A（t） and B（t） of cosmic time is applied to the field equations of f（T）, where T is the torsion scalar, T = T~μ_（νρ）S_μ^（νρ）. We calculate the equation of continuity and rewrite it as a product of two brackets, the first is a function of f（T） and the second is a function of the two unknowns A（t） and B（t）. We use two different relations between the two unknown functions A（t） and B（t） in the second bracket to solve it. Both of these relations give constant scalar torsion and solutions coincide with the de Sitter one. So,another assumption related to the contents of the matter fields is postulated. This assumption enables us to drive a solution with a non-constant value of the scalar torsion and a form of f（T） which represents ΛCDM.展开更多
近年来,在相关政策的加持下,我国农村电子商务取得了前所未有的发展。然而,受农业生产环境、技术条件、基础设施等限制,农村电子商务的发展仍然面临一些困境。加上经历了网络泡沫的寒冬,电子商务现已进入理性时代,缺乏创新的传统电商模...近年来,在相关政策的加持下,我国农村电子商务取得了前所未有的发展。然而,受农业生产环境、技术条件、基础设施等限制,农村电子商务的发展仍然面临一些困境。加上经历了网络泡沫的寒冬,电子商务现已进入理性时代,缺乏创新的传统电商模式已不能满足消费者需求,将面临被淘汰的境遇。因此,农村电子商务需要寻求新的商业模式和营销模式。F2O (Focus to online)是一种新兴的将焦点事件与电子商务结合的电商模式,对于解决农村电子商务发展困境具有启发性作用。基于此,本文结合4R营销理论从关联策略、反应策略、关系策略、回报策略探讨了F2O模式在农村电子商务中的应用。In recent years, with the support of relevant policies, rural e-commerce in our country has achieved unprecedented development. However, due to the limitations of agricultural production environment, technical conditions, and infrastructure, the development of rural e-commerce still faces some difficulties. Coupled with the cold winter of the Internet bubble, e-commerce has entered the rational era, and the traditional e-commerce model that lacks innovation can no longer meet the needs of consumers and will face the situation of being eliminated. Therefore, rural e-commerce needs to seek new business models and marketing models. F2O (Focus to online) is an emerging e-commerce model that combines focus events with e-commerce, which is enlightening to solve the dilemma of rural e-commerce development. Based on this, this paper discusses the application of F2O model in rural e-commerce from the relevancy strategy, reaction strategy, relation strategy and reward strategy combined with 4R marketing theory.展开更多
We study the effect of the non-minimal coupling between matter and geometry on the gravitational constant in the context of f(R) theories of gravity on cosmic scales. For a class of f(R) models,the result shows that t...We study the effect of the non-minimal coupling between matter and geometry on the gravitational constant in the context of f(R) theories of gravity on cosmic scales. For a class of f(R) models,the result shows that the value of the gravitational constant not only changes over time but also has the dampened oscillation behavior.Compared with the result of the standard ACDM model, the consequence suggests that the coupling between matter and geometry should be weak.展开更多
Short_term batch cultures were used to measure the phosphate_dependent growth kinetics for a marine microalga, Tetraselmis subcordiformis (Wille) Hazen, and a marine macroalga, Ulva pertusa Kjellm. Results wer...Short_term batch cultures were used to measure the phosphate_dependent growth kinetics for a marine microalga, Tetraselmis subcordiformis (Wille) Hazen, and a marine macroalga, Ulva pertusa Kjellm. Results were fitted to the Monod model. U. pertusa had a lower half_saturation constant and maximum growth rate, which were 0.016 μmol/L and 0.16 d -1 respectively, while the growth kinetics of T. subcordiformis were 0.021 μmol/L and 0.83 d -1 . Long_term semicontinuous nutrient competition experiments were performed between T. subcordiformis and U. pertusa under phosphate limitation in laboratory. Loss rates were manipulated to get the same or different resource requirement values ( R * ) of the two species. Comparison between the theoretical predictions derived from Monod kinetics and the outcome of competition experiments indicated that the Monod model could predict the results only when the R * values of the two species were significantly different, and T. subcordiformis displaced U. pertusa when they had the same resource requirements. The Monod model can only partly predict the competition results between microalga and macroalga.展开更多
基金Supported by Youth Fund Project of Zhaoqing University(QZ202235)Zhaoqing Science and Technology Plan Project(2022040311011).
文摘[Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavonoid glycosides were isolated and purified from the ethanol alcoholic extract of the roots of Liliaceae plant Chlorophytum comosum by silica gel column chromatography,macroporous resin column chromatography,Sephadex LH-20,and reverse column chromatography(ODS).The inhibitory activity of flavonoid glycosides on human nasopharyngeal carcinoma cells was analyzed by CCK-8 method,and the potential mechanism was preliminarily analyzed by molecular docking.[Results]Two flavonoid glycosides were identified as isovitexin 2″-0-rhamnoside and 7-2″-di-O-β-glucopyranosylisovitexin.Two flavonoid glycosides showed promising inhibitory effect on human nasopharyngeal carcinoma cell line 5-8F,with IC_(50) values of 24.8 and 27.5μmol/L,respectively.Molecular docking results showed that the potential targets of two flavonoid glycosides include CyclinD1,Bcl-2β-Catenin,ILK,TGF-β,in addition,two glycosides showed higher predicted binding affinity towards CyclinD1,which verifies the cytotoxicity of the two compounds on human nasopharyngeal carcinoma cell line 5-8F in vitro.[Conclusions]Two flavonoid glycosides are the active molecules in Chlorophytum comosum that can inhibit the proliferation of human nasopharyngeal carcinoma cells,and have the potential to be used in the research and development of anti nasopharyngeal carcinoma drugs.
基金Project supported by the Egyptian Ministry of Scientific Research(Project No.24-2-12)
文摘A tetrad field that is homogeneous and anisotropic which contains two unknown functions A（t） and B（t） of cosmic time is applied to the field equations of f（T）, where T is the torsion scalar, T = T~μ_（νρ）S_μ^（νρ）. We calculate the equation of continuity and rewrite it as a product of two brackets, the first is a function of f（T） and the second is a function of the two unknowns A（t） and B（t）. We use two different relations between the two unknown functions A（t） and B（t） in the second bracket to solve it. Both of these relations give constant scalar torsion and solutions coincide with the de Sitter one. So,another assumption related to the contents of the matter fields is postulated. This assumption enables us to drive a solution with a non-constant value of the scalar torsion and a form of f（T） which represents ΛCDM.
文摘近年来,在相关政策的加持下,我国农村电子商务取得了前所未有的发展。然而,受农业生产环境、技术条件、基础设施等限制,农村电子商务的发展仍然面临一些困境。加上经历了网络泡沫的寒冬,电子商务现已进入理性时代,缺乏创新的传统电商模式已不能满足消费者需求,将面临被淘汰的境遇。因此,农村电子商务需要寻求新的商业模式和营销模式。F2O (Focus to online)是一种新兴的将焦点事件与电子商务结合的电商模式,对于解决农村电子商务发展困境具有启发性作用。基于此,本文结合4R营销理论从关联策略、反应策略、关系策略、回报策略探讨了F2O模式在农村电子商务中的应用。In recent years, with the support of relevant policies, rural e-commerce in our country has achieved unprecedented development. However, due to the limitations of agricultural production environment, technical conditions, and infrastructure, the development of rural e-commerce still faces some difficulties. Coupled with the cold winter of the Internet bubble, e-commerce has entered the rational era, and the traditional e-commerce model that lacks innovation can no longer meet the needs of consumers and will face the situation of being eliminated. Therefore, rural e-commerce needs to seek new business models and marketing models. F2O (Focus to online) is an emerging e-commerce model that combines focus events with e-commerce, which is enlightening to solve the dilemma of rural e-commerce development. Based on this, this paper discusses the application of F2O model in rural e-commerce from the relevancy strategy, reaction strategy, relation strategy and reward strategy combined with 4R marketing theory.
基金Supported by the National Natural Science Foundation of China under Grant No 11647079the Scientific Research Foundation of Education Department of Yunnan Province under Grant No 2016ZZX011+1 种基金the Key Laboratory of Astroparticle Physics of Yunnan Provincethe Donglu Youth Teacher Plan of Yunnan University
文摘We study the effect of the non-minimal coupling between matter and geometry on the gravitational constant in the context of f(R) theories of gravity on cosmic scales. For a class of f(R) models,the result shows that the value of the gravitational constant not only changes over time but also has the dampened oscillation behavior.Compared with the result of the standard ACDM model, the consequence suggests that the coupling between matter and geometry should be weak.
文摘Short_term batch cultures were used to measure the phosphate_dependent growth kinetics for a marine microalga, Tetraselmis subcordiformis (Wille) Hazen, and a marine macroalga, Ulva pertusa Kjellm. Results were fitted to the Monod model. U. pertusa had a lower half_saturation constant and maximum growth rate, which were 0.016 μmol/L and 0.16 d -1 respectively, while the growth kinetics of T. subcordiformis were 0.021 μmol/L and 0.83 d -1 . Long_term semicontinuous nutrient competition experiments were performed between T. subcordiformis and U. pertusa under phosphate limitation in laboratory. Loss rates were manipulated to get the same or different resource requirement values ( R * ) of the two species. Comparison between the theoretical predictions derived from Monod kinetics and the outcome of competition experiments indicated that the Monod model could predict the results only when the R * values of the two species were significantly different, and T. subcordiformis displaced U. pertusa when they had the same resource requirements. The Monod model can only partly predict the competition results between microalga and macroalga.
