With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,off...With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,offers a promising avenue for researchers.However,the question of how to significantly enhance the performance of catalysts has gradually drawn the attention of scholars.Defect engineering,a commonly employed and effective approach to improve catalyst activity,has become a significant research focus in the catalysis field in recent years.Nonmetal vacancies have received extensive attention due to their simple form.Consequently,exploration of metal vacancies has remained stagnant for a considerable period,resulting in a scarcity of comprehensive reviews on this topic.Therefore,based on the latest research findings,this paper summarizes and consolidates the construction strategies for metal vacancies,characterization techniques,and their roles in typical energy and environmental catalytic reactions.Additionally,it outlines potential challenges in the future,aiming to provide valuable references for researchers interested in investigating metal vacancies.展开更多
This study examines the predictive roles of foreign language classroom anxiety(FLCA),foreign language enjoyment(FLE),and foreign language boredom(FLB)in English achievement among Chinese senior high school students.De...This study examines the predictive roles of foreign language classroom anxiety(FLCA),foreign language enjoyment(FLE),and foreign language boredom(FLB)in English achievement among Chinese senior high school students.Despite extensive research on anxiety in language learning,less attention has been given to boredom,and the combined effects of these three emotions on English achievement remain under-explored,particularly among high school students in China.To address these gaps,a sample of 142 students from Guangzhou was surveyed using questionnaires to assess their emotional experiences and English achievement.The research found that FLE exhibited a positive correlation with academic performance,while FLCA and FLB showed negative associations.Notably,FLE was the most significant predictor of English achievement,followed by FLCA and FLB.Gender differences were observed,with male students reporting significantly higher levels of environmental enjoyment,while female students experienced significantly greater communication anxiety.On this basis,this paper offers suggestions on how to enhance senior high school students’FLE while mitigating FLCA and FLB,thereby promoting more effective and sustained English learning.展开更多
In this letter,we comment on the article by Xuan Yuan et al,published in the recent issue of the World Journal of Gastroenterology.Mixed lineage kinase domainlike protein(MLKL)exhibits cell-type-specific functions in ...In this letter,we comment on the article by Xuan Yuan et al,published in the recent issue of the World Journal of Gastroenterology.Mixed lineage kinase domainlike protein(MLKL)exhibits cell-type-specific functions in liver parenchymal and non-parenchymal cells,playing dual roles in the pathogenesis of liver diseases.In hepatocytes,MLKL primarily mediates necroptosis and inhibits autophagy,thereby exacerbating liver injury.Conversely,in non-parenchymal liver cells,MLKL modulates inflammatory responses and promotes fibrotic processes,thereby driving disease progression.Notably,MLKL also demonstrates protective functions under specific conditions.For instance,MLKL can inhibit intracellular bacterial replication,promote endosomal trafficking,and facilitate the generation and release of extracellular vesicles,potentially exerting hepatoprotective effects.Understanding these cell-type-specific mechanisms of MLKL action,including its dual roles in promoting injury and providing protection,is crucial for elucidating the complex pathogenesis of liver diseases and developing targeted therapeutic strategies.展开更多
This research focused on the social roles of women in Al-Abassiya locality,South Kordofan State,examining the obstacles they face and the impact on their participation in peace building.Using qualitative methods,data ...This research focused on the social roles of women in Al-Abassiya locality,South Kordofan State,examining the obstacles they face and the impact on their participation in peace building.Using qualitative methods,data were collected through various means,revealing that conflicts have significantly affected women’s lives,particularly in rural areas.Women play key roles in family,education,health services,and humanitarian aid,but their involvement in conflict resolution and peace building activities is limited.Obstacles include cognitive,economic,social,and institutional barriers.Recommendations include providing education and training programs,strengthening economic status,ensuring women’s representation in decision-making bodies,advocating for legal reforms promoting gender equality,improving access to information technologies,educating communities on women’s involvement in peace building,and providing support services for women affected by conflicts.展开更多
The role of university English instructors has evolved significantly over the years,encompassing various aspects.This paper explores the evolution of the role of university English instructors and examines the current...The role of university English instructors has evolved significantly over the years,encompassing various aspects.This paper explores the evolution of the role of university English instructors and examines the current challenges and opportunities they face in today’s educational landscape.It delves into the multifaceted nature of their responsibilities and discusses the importance of continuous professional development to meet the evolving needs of students and the demands of the profession.展开更多
Although metal oxide-zeolite hybrid materials have long been known to achieve enhanced catalytic activity and selectivity in NO_(x)removal reactions through the inter-particle diffusion of intermediate species,their s...Although metal oxide-zeolite hybrid materials have long been known to achieve enhanced catalytic activity and selectivity in NO_(x)removal reactions through the inter-particle diffusion of intermediate species,their subsequent reaction mechanism on acid sites is still unclear and requires investigation.In this study,the distribution of Brønsted/Lewis acid sites in the hybrid materials was precisely adjusted by introducing potassium ions,which not only selectively bind to Brønsted acid sites but also potentially affect the formation and diffusion of activated NO species.Systematic in situ diffuse reflectance infrared Fourier transform spectroscopy analyses coupled with selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR)reaction demonstrate that the Lewis acid sites over MnO_(x)are more active for NO reduction but have lower selectivity to N_(2)than Brønsted acids sites.Brønsted acid sites primarily produce N_(2),whereas Lewis acid sites primarily produce N_(2)O,contributing to unfavorable N_(2)selectivity.The Brønsted acid sites present in Y zeolite,which are stronger than those on MnO_(x),accelerate the NH_(3)-SCR reaction in which the nitrite/nitrate species diffused from the MnO_(x)particles rapidly convert into the N_(2).Therefore,it is important to design the catalyst so that the activated NO species formed in MnO_(x)diffuse to and are selectively decomposed on the Brønsted acid sites of H-Y zeolite rather than that of MnO_(x)particle.For the physically mixed H-MnO_(x)+H-Y sample,the abundant Brønsted/Lewis acid sites in H-MnO_(x)give rise to significant consumption of activated NO species before their inter-particle diffusion,thereby hindering the enhancement of the synergistic effects.Furthermore,we found that the intercalated K+in K-MnO_(x)has an unexpected favorable role in the NO reduction rate,probably owing to faster diffusion of the activated NO species on K-MnO_(x)than H-MnO_(x).This study will help to design promising metal oxide-zeolite hybrid catalysts by identifying the role of the acid sites in two different constituents.展开更多
The paper, with the backdrop of web-based autonomous learning put forward by the recent college English teaching reform, aims to explore teachers＇ roles in this learning process in students＇ perception through the m...The paper, with the backdrop of web-based autonomous learning put forward by the recent college English teaching reform, aims to explore teachers＇ roles in this learning process in students＇ perception through the means of questionnaires and interviews. It further analyzes the possible reasons why students perceive their teachers＇ roles in such a way, in the hope of providing some implications for web-based college English autonomous learning.展开更多
This paper gives an account of characteristics of the intensive reading in English teaching, and change of teachers’ roles in the learner-centered teaching approach. Suggestions are put forward as to how to be a qual...This paper gives an account of characteristics of the intensive reading in English teaching, and change of teachers’ roles in the learner-centered teaching approach. Suggestions are put forward as to how to be a qualified teacher in the intensive reading class accordingly.展开更多
The main purpose of this paper was to examine female roles portrayed by advertising. More specifically, the questions that motivated this research project were ＂What messages about women have been given to society th...The main purpose of this paper was to examine female roles portrayed by advertising. More specifically, the questions that motivated this research project were ＂What messages about women have been given to society through advertisement？＂ and ＂Have these portrayals been changed during the past decades？＂ The study consisted of a systematic content analysis of Brazilian commercials from 1973 to 2000. The population from which this sample was drawn consisted of Brazilian commercials which got an award in international and national festivals. A probabilistic sample procedure was employed. Ninety five pieces were selected. The categories and operational rules used in the study were developed based on previous research. This study has proposed that female images in advertising are depicted in three different ways： stereotyped, idealized, and plural portrayals. Our results have revealed that some specific images have changed, however, they continued to be stereotyped and idealized.展开更多
Traditionally, in a teacher-centered class, students are deprived of right, for teachers take up the platform and play a “leading” role. What are the college English teacher′s possible roles? The paper tends to she...Traditionally, in a teacher-centered class, students are deprived of right, for teachers take up the platform and play a “leading” role. What are the college English teacher′s possible roles? The paper tends to shed light on it by kicking the teacher′s traditional roles.展开更多
Natural products have gained popularity worldwide for promoting healthcare, as well as disease prevention. Alkaloids are important chemical compounds that serve as a rich reservoir for drug discovery. Several alkaloid...Natural products have gained popularity worldwide for promoting healthcare, as well as disease prevention. Alkaloids are important chemical compounds that serve as a rich reservoir for drug discovery. Several alkaloids isolated from natural herbs exhibit antiproliferation, antibacterial, antiviral, insecticidal, and antimetastatic effects on various types of cancers both in vitro and in vivo. This paper focuses on the naturally-derived alkaloids such as berberine, matrine, piperine, fritillarine, and rhynchophylline, etc., and summarizes the action mechanisms of these compounds. Based on the information in the literature that is summarized in this paper, the use of alkaloids as drugs is very promising, but more research and clinical trials are necessary before final recommendations on specific alkaloids can be made. Following this, it is hoped that as a result of this review, there will be a greater awareness of the excellent promise that natural alkaloids show for use in the therapy of diseases.展开更多
Theoretic and practical significance has been highlighted in the research of the roles and functions of destinations,as destinations are restricted by the spatial structure based on tourist flow network from the persp...Theoretic and practical significance has been highlighted in the research of the roles and functions of destinations,as destinations are restricted by the spatial structure based on tourist flow network from the perspective of relationship.This article conducted an empirical analysis for Tourism Region of South Anhui(TRSA) and revealed the necessity and feasibility of studying the roles and functions of destinations from tourist flow network's perspective.The automorphic equivalence analysis and centrality analysis were used to classify 16 destinations in TRSA into six role types:tourist flow distribution center,hub of tourist flows,passageway destination,common touring destination,attached touring destination,and nearly isolated destination.Some suggestions were given on suitable infrastructure construction and destinations service designs according to their functions in network.This destination role positioning was based on tourist flow network structure in integral and macroscopic way.It provided an important reference for the balanced and harmonious development of all the destinations of TRSA.In addition,this article verified the applicability of social network analysis on tourist flow research in local scale,and expanded this method to destination role and function positioning.展开更多
This paper proposes a new distributed coordinated control scheme based on heterogeneous roles for Unmanned Aerial Vehicle(UAV)swarm to achieve formation control.First,the framework of the distributed coordinated contr...This paper proposes a new distributed coordinated control scheme based on heterogeneous roles for Unmanned Aerial Vehicle(UAV)swarm to achieve formation control.First,the framework of the distributed coordinated control scheme is designed on the basis of Distributed Model Predictive Control(DMPC).Then,the effect of heterogeneous roles including leader,coordinator and follower is discussed,and the role-based cost functions are developed to improve the performance of coordinated control for UAV swarm.Furthermore,a group of coordination strategies are proposed for UAVs with different roles to achieve swarm conflict resolution.Numerical simulations demonstrate that the presented distributed coordinated control scheme is effective to formulate and maintain the desired formation for the UAV swarm.展开更多
Group role assignment(GRA)is originally a complex problem in role-based collaboration(RBC).The solution to GRA provides modelling techniques for more complex problems.GRA with constraints(GRA+)is categorized as a clas...Group role assignment(GRA)is originally a complex problem in role-based collaboration(RBC).The solution to GRA provides modelling techniques for more complex problems.GRA with constraints(GRA+)is categorized as a class of complex assignment problems.At present,there are few generally efficient solutions to this category of problems.Each special problem case requires a specific solution.Group multi-role assignment(GMRA)and GRA with conflicting agents on roles(GRACAR)are two problem cases in GRA+.The contributions of this paper include:1)The formalization of a new problem of GRA+,called group multi-role assignment with conflicting roles and agents(GMAC),which is an extension to the combination of GMRA and GRACAR;2)A practical solution based on an optimization platform;3)A sufficient condition,used in planning,for solving GMAC problems;and 4)A clear presentation of the benefits in avoiding conflicts when dealing with GMAC.The proposed methods are verified by experiments,simulations,proofs and analysis.展开更多
As a new member of carbon material family, carbon quantum dots (CQDs) have attracted tremendous attentions for their potentials in the heterogeneous photocatalysis applications. Due to the unique microstructure and op...As a new member of carbon material family, carbon quantum dots (CQDs) have attracted tremendous attentions for their potentials in the heterogeneous photocatalysis applications. Due to the unique microstructure and optical properties, the roles of CQDs played in the CQDs-based photocatalytic systems have been found to be diverse with the continuous researches in this regard. Herein, we provide a concise minireview to elaborate the multifarious roles of CQDs in photocatalysis, including photoelectron mediator and acceptor, photosensitizer, photocatalyst, reducing agent for metal salt, enhancing adsorption capacity and spectral converter. In addition, the perspectives on future research trends and challenges are proposed, which are anticipated to stimulate further research into this promising field on designing a variety of efficient CQDs-based photocatalysts for solar energy conversion. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved.展开更多
With continuing advances in technology, computer-assisted instruction provides opportunities for individualized, interactive instruction. The philosophy of constructivism has encouraged instructional designers to crea...With continuing advances in technology, computer-assisted instruction provides opportunities for individualized, interactive instruction. The philosophy of constructivism has encouraged instructional designers to create less behavioral, more democratic programs that promote learner control. In the area of ESL (English as a second language), computers are seen to be a highly motivating, instructional tool.展开更多
Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting prop...Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting properties in enhancing light absorption,electron transfer dynamics,and surface reactions.Currently,numerous efforts have shown that the properties of GR,which are closely correlated to the photocatalytic performance of GR‐based composites are significantly affected by the synthesis methods.Herein,we first introduce the optimization strategies of GR‐based hybrids and then elaborate the synthesis of GR‐based composite photocatalysts oriented by manifold roles of GR in photoredox catalysis,containing photoelectron mediator and acceptor,improving adsorption capacity,regulating light absorption range and intensity,as well as macromolecular photosensitizer.Beyond that,a brief outlook on the challenges in this burgeoning research field and potential evolution strategies for enhancing the photoactivity of GR‐based hybrids is presented and we anticipate that this review could provide some enlightenments for the rational construction and application of multifunctional GR‐based composite photocatalysts.展开更多
Endoscopic ultrasound(EUS), developed in the 1980 s, was initially predominantly used for guidance of fine needle aspiration; the last 25 years, however, have witnessed a major expansion of EUS to various applications...Endoscopic ultrasound(EUS), developed in the 1980 s, was initially predominantly used for guidance of fine needle aspiration; the last 25 years, however, have witnessed a major expansion of EUS to various applications, both diagnostic and therapeutic. EUS has become much more than a tool to differentiate different tissue densities;tissue can now be characterized in great detail using modalities such as elastography; the extent of tissue vascularity can now be learned with increasing precision. Using these various techniques, targets for biopsy can be precisely pinpointed. Upon reaching the target, tissue can then be examined microscopically in real-time, ensuring optimal targeting and diagnosis. This article provides a comprehensive review of the various current roles of EUS, including drainage of lesions, visualization and characterization of lesions, injection, surgery, and vascular intervention. With EUS technology continuing to develop exponentially, the article emphasizes the future directions of each modality.展开更多
Exosomes are vesicles secreted by a variety of living cells,containing proteins,RNA and other components,which are nanoscale capsules commonly existed in the body.Exosomes play important roles in a variety of physiolo...Exosomes are vesicles secreted by a variety of living cells,containing proteins,RNA and other components,which are nanoscale capsules commonly existed in the body.Exosomes play important roles in a variety of physiological and pathological processes by participating in material and information exchange between cells,which can playmultiple roles in tumor treatment.On the one hand,exosomes can be used as carriers and biomarkers,participate in the apoptosis signaling pathway and improve chemotherapy resistance,thus playing beneficial roles in tumor treatment.On the other hand,exosomes play unfavorable roles in tumor treatment.Tumor cell exosomes contain PD-L1,which is a nuclear weapon for tumor growth,metastasis,and immunosuppression.In addition,exosomes can not only promote the epithelial-mesenchymal transition process,tumor angiogenesis and chemoresistance,but also participate in the autocrine pathway.In this review,the multiple roles of exosomes and their prospects in the treatment of tumor were reviewed in detail.展开更多
Cardiolipin （CL） is a phospholipid exclusively localized in inner mitochondrial membrane where it is required for oxidative phosphorylation, ATP synthesis, and mitochondrial bioenergetics. The biological functions o...Cardiolipin （CL） is a phospholipid exclusively localized in inner mitochondrial membrane where it is required for oxidative phosphorylation, ATP synthesis, and mitochondrial bioenergetics. The biological functions of CL are thought to depend on its acyl chain composition which is dominated by linoleic acids in metabolically active tissues. This unique feature is not derived from the de novo biosynthesis of CL, rather from a remodeling process that involves in phospholipases and transacylase/acyltransferase. The remodeling process is also believed to be responsible for generation of CL species that causes oxidative stress and mitochondrial dysfunction. CL is highly sensitive to oxidative damages by reactive oxygen species （ROS） due to its high content in polyunsaturated fatty acids and location near the site of ROS production. Consequently, pathological remodeling of CL has been implicated in the etiology of mitochondrial dysfunction commonly associated with diabetes, obesity, heart failure, neurodegeneration, and aging that are characterized by oxidative stress, CL deficiency, and abnormal CL species. This review summarizes recent progresses in molecular, enzymatic, lipidomic, and metabolic studies that support a critical regulatory role of pathological CL remodeling as a missing link between oxidative stress and mitochondrial dysfunction in metabolic diseases and aging.展开更多
基金financially supported by National Key R&D Program of China(2021YFB3500702)National Natural Science Foundation of China(Nos.21677010 and 51808037)Special fund of Beijing Key Laboratory of Indoor Air Quality Evaluation and Control(No.BZ0344KF21-04).
文摘With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,offers a promising avenue for researchers.However,the question of how to significantly enhance the performance of catalysts has gradually drawn the attention of scholars.Defect engineering,a commonly employed and effective approach to improve catalyst activity,has become a significant research focus in the catalysis field in recent years.Nonmetal vacancies have received extensive attention due to their simple form.Consequently,exploration of metal vacancies has remained stagnant for a considerable period,resulting in a scarcity of comprehensive reviews on this topic.Therefore,based on the latest research findings,this paper summarizes and consolidates the construction strategies for metal vacancies,characterization techniques,and their roles in typical energy and environmental catalytic reactions.Additionally,it outlines potential challenges in the future,aiming to provide valuable references for researchers interested in investigating metal vacancies.
文摘This study examines the predictive roles of foreign language classroom anxiety(FLCA),foreign language enjoyment(FLE),and foreign language boredom(FLB)in English achievement among Chinese senior high school students.Despite extensive research on anxiety in language learning,less attention has been given to boredom,and the combined effects of these three emotions on English achievement remain under-explored,particularly among high school students in China.To address these gaps,a sample of 142 students from Guangzhou was surveyed using questionnaires to assess their emotional experiences and English achievement.The research found that FLE exhibited a positive correlation with academic performance,while FLCA and FLB showed negative associations.Notably,FLE was the most significant predictor of English achievement,followed by FLCA and FLB.Gender differences were observed,with male students reporting significantly higher levels of environmental enjoyment,while female students experienced significantly greater communication anxiety.On this basis,this paper offers suggestions on how to enhance senior high school students’FLE while mitigating FLCA and FLB,thereby promoting more effective and sustained English learning.
基金Supported by the Science and Technology Planning Projects of Guizhou Province,No.QKHJC-ZK[2022]YB642Health Research Project of Guizhou Province,No.gzwkj2024-324,and No.gzwkj2024-103+2 种基金WBE Liver Fibrosis Foundation,No.CFHPC2025028Beijing Liver and Gallbladder Mutual Aid Public Welfare Foundation Artificial Liver Special Fund,No.iGandanF-1082024-Rgg018Student Innovation and Entrepreneurship Training Program of Zunyi Medical University,No.S2024106612360.
文摘In this letter,we comment on the article by Xuan Yuan et al,published in the recent issue of the World Journal of Gastroenterology.Mixed lineage kinase domainlike protein(MLKL)exhibits cell-type-specific functions in liver parenchymal and non-parenchymal cells,playing dual roles in the pathogenesis of liver diseases.In hepatocytes,MLKL primarily mediates necroptosis and inhibits autophagy,thereby exacerbating liver injury.Conversely,in non-parenchymal liver cells,MLKL modulates inflammatory responses and promotes fibrotic processes,thereby driving disease progression.Notably,MLKL also demonstrates protective functions under specific conditions.For instance,MLKL can inhibit intracellular bacterial replication,promote endosomal trafficking,and facilitate the generation and release of extracellular vesicles,potentially exerting hepatoprotective effects.Understanding these cell-type-specific mechanisms of MLKL action,including its dual roles in promoting injury and providing protection,is crucial for elucidating the complex pathogenesis of liver diseases and developing targeted therapeutic strategies.
基金The researcher would like to thank Dr.Afag Mohamed Sadig as supervisor and Prof Hazel Barrett as co-supervisor for the paper。
文摘This research focused on the social roles of women in Al-Abassiya locality,South Kordofan State,examining the obstacles they face and the impact on their participation in peace building.Using qualitative methods,data were collected through various means,revealing that conflicts have significantly affected women’s lives,particularly in rural areas.Women play key roles in family,education,health services,and humanitarian aid,but their involvement in conflict resolution and peace building activities is limited.Obstacles include cognitive,economic,social,and institutional barriers.Recommendations include providing education and training programs,strengthening economic status,ensuring women’s representation in decision-making bodies,advocating for legal reforms promoting gender equality,improving access to information technologies,educating communities on women’s involvement in peace building,and providing support services for women affected by conflicts.
文摘The role of university English instructors has evolved significantly over the years,encompassing various aspects.This paper explores the evolution of the role of university English instructors and examines the current challenges and opportunities they face in today’s educational landscape.It delves into the multifaceted nature of their responsibilities and discusses the importance of continuous professional development to meet the evolving needs of students and the demands of the profession.
文摘Although metal oxide-zeolite hybrid materials have long been known to achieve enhanced catalytic activity and selectivity in NO_(x)removal reactions through the inter-particle diffusion of intermediate species,their subsequent reaction mechanism on acid sites is still unclear and requires investigation.In this study,the distribution of Brønsted/Lewis acid sites in the hybrid materials was precisely adjusted by introducing potassium ions,which not only selectively bind to Brønsted acid sites but also potentially affect the formation and diffusion of activated NO species.Systematic in situ diffuse reflectance infrared Fourier transform spectroscopy analyses coupled with selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR)reaction demonstrate that the Lewis acid sites over MnO_(x)are more active for NO reduction but have lower selectivity to N_(2)than Brønsted acids sites.Brønsted acid sites primarily produce N_(2),whereas Lewis acid sites primarily produce N_(2)O,contributing to unfavorable N_(2)selectivity.The Brønsted acid sites present in Y zeolite,which are stronger than those on MnO_(x),accelerate the NH_(3)-SCR reaction in which the nitrite/nitrate species diffused from the MnO_(x)particles rapidly convert into the N_(2).Therefore,it is important to design the catalyst so that the activated NO species formed in MnO_(x)diffuse to and are selectively decomposed on the Brønsted acid sites of H-Y zeolite rather than that of MnO_(x)particle.For the physically mixed H-MnO_(x)+H-Y sample,the abundant Brønsted/Lewis acid sites in H-MnO_(x)give rise to significant consumption of activated NO species before their inter-particle diffusion,thereby hindering the enhancement of the synergistic effects.Furthermore,we found that the intercalated K+in K-MnO_(x)has an unexpected favorable role in the NO reduction rate,probably owing to faster diffusion of the activated NO species on K-MnO_(x)than H-MnO_(x).This study will help to design promising metal oxide-zeolite hybrid catalysts by identifying the role of the acid sites in two different constituents.
文摘The paper, with the backdrop of web-based autonomous learning put forward by the recent college English teaching reform, aims to explore teachers＇ roles in this learning process in students＇ perception through the means of questionnaires and interviews. It further analyzes the possible reasons why students perceive their teachers＇ roles in such a way, in the hope of providing some implications for web-based college English autonomous learning.
文摘This paper gives an account of characteristics of the intensive reading in English teaching, and change of teachers’ roles in the learner-centered teaching approach. Suggestions are put forward as to how to be a qualified teacher in the intensive reading class accordingly.
文摘The main purpose of this paper was to examine female roles portrayed by advertising. More specifically, the questions that motivated this research project were ＂What messages about women have been given to society through advertisement？＂ and ＂Have these portrayals been changed during the past decades？＂ The study consisted of a systematic content analysis of Brazilian commercials from 1973 to 2000. The population from which this sample was drawn consisted of Brazilian commercials which got an award in international and national festivals. A probabilistic sample procedure was employed. Ninety five pieces were selected. The categories and operational rules used in the study were developed based on previous research. This study has proposed that female images in advertising are depicted in three different ways： stereotyped, idealized, and plural portrayals. Our results have revealed that some specific images have changed, however, they continued to be stereotyped and idealized.
文摘Traditionally, in a teacher-centered class, students are deprived of right, for teachers take up the platform and play a “leading” role. What are the college English teacher′s possible roles? The paper tends to shed light on it by kicking the teacher′s traditional roles.
基金supported by the grants from the Key Program of Natural Science Foundation of State(Nos.90709019,81173500,81373930,81302905,81102556,81202639)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Nos.2011BAI03B03,2011BAI03B06,2011BAI03B08)the National Key Subject of Drug Innovation(No.2009ZX09502-005)
文摘Natural products have gained popularity worldwide for promoting healthcare, as well as disease prevention. Alkaloids are important chemical compounds that serve as a rich reservoir for drug discovery. Several alkaloids isolated from natural herbs exhibit antiproliferation, antibacterial, antiviral, insecticidal, and antimetastatic effects on various types of cancers both in vitro and in vivo. This paper focuses on the naturally-derived alkaloids such as berberine, matrine, piperine, fritillarine, and rhynchophylline, etc., and summarizes the action mechanisms of these compounds. Based on the information in the literature that is summarized in this paper, the use of alkaloids as drugs is very promising, but more research and clinical trials are necessary before final recommendations on specific alkaloids can be made. Following this, it is hoped that as a result of this review, there will be a greater awareness of the excellent promise that natural alkaloids show for use in the therapy of diseases.
基金Under the auspices of National Natural Science Foundation of China(No.41001070,40801054,40371030)
文摘Theoretic and practical significance has been highlighted in the research of the roles and functions of destinations,as destinations are restricted by the spatial structure based on tourist flow network from the perspective of relationship.This article conducted an empirical analysis for Tourism Region of South Anhui(TRSA) and revealed the necessity and feasibility of studying the roles and functions of destinations from tourist flow network's perspective.The automorphic equivalence analysis and centrality analysis were used to classify 16 destinations in TRSA into six role types:tourist flow distribution center,hub of tourist flows,passageway destination,common touring destination,attached touring destination,and nearly isolated destination.Some suggestions were given on suitable infrastructure construction and destinations service designs according to their functions in network.This destination role positioning was based on tourist flow network structure in integral and macroscopic way.It provided an important reference for the balanced and harmonious development of all the destinations of TRSA.In addition,this article verified the applicability of social network analysis on tourist flow research in local scale,and expanded this method to destination role and function positioning.
基金co-supported by the National Natural Science Foundation of China(Nos.61803009,61903084)Fundamental Research Funds for the Central Universities of China(No.YWF-20-BJ-J-542)the National Science Foundation of Jiangsu Province,China(No.BK20180358).
文摘This paper proposes a new distributed coordinated control scheme based on heterogeneous roles for Unmanned Aerial Vehicle(UAV)swarm to achieve formation control.First,the framework of the distributed coordinated control scheme is designed on the basis of Distributed Model Predictive Control(DMPC).Then,the effect of heterogeneous roles including leader,coordinator and follower is discussed,and the role-based cost functions are developed to improve the performance of coordinated control for UAV swarm.Furthermore,a group of coordination strategies are proposed for UAVs with different roles to achieve swarm conflict resolution.Numerical simulations demonstrate that the presented distributed coordinated control scheme is effective to formulate and maintain the desired formation for the UAV swarm.
基金supported in part by Natural Sciences and Engineering Research Council,Canada(NSERC)(RGPIN-2018-04818)the funding from the Innovation for Defence Excellence and Security(IDEaS)Program from the Canadian Department of National Defence(DND)。
文摘Group role assignment(GRA)is originally a complex problem in role-based collaboration(RBC).The solution to GRA provides modelling techniques for more complex problems.GRA with constraints(GRA+)is categorized as a class of complex assignment problems.At present,there are few generally efficient solutions to this category of problems.Each special problem case requires a specific solution.Group multi-role assignment(GMRA)and GRA with conflicting agents on roles(GRACAR)are two problem cases in GRA+.The contributions of this paper include:1)The formalization of a new problem of GRA+,called group multi-role assignment with conflicting roles and agents(GMAC),which is an extension to the combination of GMRA and GRACAR;2)A practical solution based on an optimization platform;3)A sufficient condition,used in planning,for solving GMAC problems;and 4)A clear presentation of the benefits in avoiding conflicts when dealing with GMAC.The proposed methods are verified by experiments,simulations,proofs and analysis.
基金financial support from the key project of the National Natural Science Foundation of China (U1463204)the project of National Natural Science Foundation of China (NSFC) (20903023,21173045)+4 种基金the Award Program for Minjiang Scholar Professorshipthe Natural Science Foundation (NSF) of Fujian Province for Distinguished Young Investigator Grant (2012J06003)the Independent Research Project of State Key Laboratory of Photocatalysis on Energy and Environment (No.2014A05)the 1st Program of Fujian Province for Top Creative Young Talentsthe Program for Returned High-Level Overseas Chinese Scholars of Fujian Province
文摘As a new member of carbon material family, carbon quantum dots (CQDs) have attracted tremendous attentions for their potentials in the heterogeneous photocatalysis applications. Due to the unique microstructure and optical properties, the roles of CQDs played in the CQDs-based photocatalytic systems have been found to be diverse with the continuous researches in this regard. Herein, we provide a concise minireview to elaborate the multifarious roles of CQDs in photocatalysis, including photoelectron mediator and acceptor, photosensitizer, photocatalyst, reducing agent for metal salt, enhancing adsorption capacity and spectral converter. In addition, the perspectives on future research trends and challenges are proposed, which are anticipated to stimulate further research into this promising field on designing a variety of efficient CQDs-based photocatalysts for solar energy conversion. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved.
文摘With continuing advances in technology, computer-assisted instruction provides opportunities for individualized, interactive instruction. The philosophy of constructivism has encouraged instructional designers to create less behavioral, more democratic programs that promote learner control. In the area of ESL (English as a second language), computers are seen to be a highly motivating, instructional tool.
文摘Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting properties in enhancing light absorption,electron transfer dynamics,and surface reactions.Currently,numerous efforts have shown that the properties of GR,which are closely correlated to the photocatalytic performance of GR‐based composites are significantly affected by the synthesis methods.Herein,we first introduce the optimization strategies of GR‐based hybrids and then elaborate the synthesis of GR‐based composite photocatalysts oriented by manifold roles of GR in photoredox catalysis,containing photoelectron mediator and acceptor,improving adsorption capacity,regulating light absorption range and intensity,as well as macromolecular photosensitizer.Beyond that,a brief outlook on the challenges in this burgeoning research field and potential evolution strategies for enhancing the photoactivity of GR‐based hybrids is presented and we anticipate that this review could provide some enlightenments for the rational construction and application of multifunctional GR‐based composite photocatalysts.
文摘Endoscopic ultrasound(EUS), developed in the 1980 s, was initially predominantly used for guidance of fine needle aspiration; the last 25 years, however, have witnessed a major expansion of EUS to various applications, both diagnostic and therapeutic. EUS has become much more than a tool to differentiate different tissue densities;tissue can now be characterized in great detail using modalities such as elastography; the extent of tissue vascularity can now be learned with increasing precision. Using these various techniques, targets for biopsy can be precisely pinpointed. Upon reaching the target, tissue can then be examined microscopically in real-time, ensuring optimal targeting and diagnosis. This article provides a comprehensive review of the various current roles of EUS, including drainage of lesions, visualization and characterization of lesions, injection, surgery, and vascular intervention. With EUS technology continuing to develop exponentially, the article emphasizes the future directions of each modality.
文摘Exosomes are vesicles secreted by a variety of living cells,containing proteins,RNA and other components,which are nanoscale capsules commonly existed in the body.Exosomes play important roles in a variety of physiological and pathological processes by participating in material and information exchange between cells,which can playmultiple roles in tumor treatment.On the one hand,exosomes can be used as carriers and biomarkers,participate in the apoptosis signaling pathway and improve chemotherapy resistance,thus playing beneficial roles in tumor treatment.On the other hand,exosomes play unfavorable roles in tumor treatment.Tumor cell exosomes contain PD-L1,which is a nuclear weapon for tumor growth,metastasis,and immunosuppression.In addition,exosomes can not only promote the epithelial-mesenchymal transition process,tumor angiogenesis and chemoresistance,but also participate in the autocrine pathway.In this review,the multiple roles of exosomes and their prospects in the treatment of tumor were reviewed in detail.
基金supported in part by grants NIH(DK076685,Y.S.)Pennsylvania Department of Health using Tobacco Settlement Funds(10-K-273,Y.S.)
文摘Cardiolipin （CL） is a phospholipid exclusively localized in inner mitochondrial membrane where it is required for oxidative phosphorylation, ATP synthesis, and mitochondrial bioenergetics. The biological functions of CL are thought to depend on its acyl chain composition which is dominated by linoleic acids in metabolically active tissues. This unique feature is not derived from the de novo biosynthesis of CL, rather from a remodeling process that involves in phospholipases and transacylase/acyltransferase. The remodeling process is also believed to be responsible for generation of CL species that causes oxidative stress and mitochondrial dysfunction. CL is highly sensitive to oxidative damages by reactive oxygen species （ROS） due to its high content in polyunsaturated fatty acids and location near the site of ROS production. Consequently, pathological remodeling of CL has been implicated in the etiology of mitochondrial dysfunction commonly associated with diabetes, obesity, heart failure, neurodegeneration, and aging that are characterized by oxidative stress, CL deficiency, and abnormal CL species. This review summarizes recent progresses in molecular, enzymatic, lipidomic, and metabolic studies that support a critical regulatory role of pathological CL remodeling as a missing link between oxidative stress and mitochondrial dysfunction in metabolic diseases and aging.
