期刊文献+
共找到153,895篇文章
< 1 2 250 >
每页显示 20 50 100
Conflicts & Immigration Impacts on Built Environment: A Case Study of Arab Marshes in Iraq
1
作者 Ola Saad Znad 《Journal of Geoscience and Environment Protection》 2024年第9期33-50,共18页
The importance of water to our lives cannot be overemphasized as it is the source of all living things. Water scarcity is a concern in many Middle Eastern nations due to war and politics. Many people lose their essenc... The importance of water to our lives cannot be overemphasized as it is the source of all living things. Water scarcity is a concern in many Middle Eastern nations due to war and politics. Many people lose their essence due to actions made by their rulers, such as the Marsh Arabs. Water and biodiversity should be considered, and governments should be held accountable for attaining a more balanced lifestyle and reducing immigrant levels. Many academics have also explored the hydro-immigration of marshland residents. They suffer more hazards due to a lack of money, poor education, and social instability than their colleagues who remain in their own country. Furthermore, they have insufficient health care and have difficulty integrating into the new community. This implies that not all nations that receive such migrants can implement programs to assist the immigrants. This research reveals how wars, hydro-politics, and immigration issues have drastically affected architecture and social structures in the Arab Marshes region, leading to ecological destruction, mass migrations, and cultural loss. Therefore, this work focuses on the need to critically investigate all factors covered within the context of this research. 展开更多
关键词 immigration Hydro Politics Social and Culture ECOLOGY
下载PDF
Logistics,Supply Chain Management,and Taiwan residents Immigration Assessed in Light of Globalization
2
作者 Shiann Ming Wu 《Chinese Business Review》 2024年第3期114-124,共11页
Organizations regardless of size can take advantage of the market dynamics brought about by globalization.Supply chain management is crucial for large organizations,especially with regard to the costs,complexity,and r... Organizations regardless of size can take advantage of the market dynamics brought about by globalization.Supply chain management is crucial for large organizations,especially with regard to the costs,complexity,and risks of its large,often global,supply chains.From technology to risk management,learning what it takes to navigate transportation and logistics business management in today’s volatile world is critical.Human migration has accelerated in light of globalization and rapid advances in transportation(particularly aviation)technology.This study investigated the connection between logistics and supply chain management in the age of globalization;reviewed the migration,settlement,and naturalization of Taiwan residents immigrants along the West Coast of the United States;and theoretically analyzed the forces that have led to the construction of the Taiwan residents immigrant community.Taiwan residents immigrants and their settlement are affected by global forces,and factors such as their cross-cultural trade,the characteristics of diasporic communities,and their national identity can provide scholarly and pedagogical insights. 展开更多
关键词 logistics management supply chain management Taiwan residents immigrant cross-cultural trade national identity
下载PDF
Intercontinental comparison of phylogenetic relatedness in introduced plants at the transition from naturalization to invasion:A case study on the floras of South Africa and China 被引量:1
3
作者 Hong Qian 《Plant Diversity》 SCIE CAS CSCD 2023年第4期363-368,共6页
Invasive species may pose significant threats to biodiversity and ecosystem structure and functioning.The number of introduced species that have become invasive is substantial and is rapidly increasing.Identifying pot... Invasive species may pose significant threats to biodiversity and ecosystem structure and functioning.The number of introduced species that have become invasive is substantial and is rapidly increasing.Identifying potentially invasive species and preventing their expansion are of critical importance in invasion ecology.Phylogenetic relatedness between invasive and native species has been used in predicting invasion success.Previous studies on the phylogenetic relatedness of plants at the transition from naturalization to invasion have shown mixed results,which may be because different methods were used in different studies.Here,I use the same method to analyze two comprehensive data sets from South Africa and China,using two phylogenetic metrics reflecting deep and shallow evolutionary histories,to address the question whether the probability of becoming invasive is higher for naturalized species distantly related to the native flora.My study suggests that the probability of becoming invasive is higher for naturalized species closely related to the native flora.The finding of my study is consistent with Darwin's preadaptation hypothesis. 展开更多
关键词 ANGIOSPERMS Exotic species Introduced species Invasive species naturalized species Phylogenetic relatedness
下载PDF
Biomimetic natural biomaterials for tissue engineering and regenerative medicine:new biosynthesis methods,recent advances,and emerging applications 被引量:5
4
作者 Shuai Liu Jiang-Ming Yu +11 位作者 Yan-Chang Gan Xiao-Zhong Qiu Zhe-Chen Gao Huan Wang Shi-Xuan Chen Yuan Xiong Guo-Hui Liu Si-En Lin Alec McCarthy Johnson V.John Dai-Xu Wei Hong-Hao Hou 《Military Medical Research》 SCIE CAS CSCD 2024年第1期50-79,共30页
Biomimetic materials have emerged as attractive and competitive alternatives for tissue engineering(TE)and regenerative medicine.In contrast to conventional biomaterials or synthetic materials,biomimetic scaffolds bas... Biomimetic materials have emerged as attractive and competitive alternatives for tissue engineering(TE)and regenerative medicine.In contrast to conventional biomaterials or synthetic materials,biomimetic scaffolds based on natural biomaterial can offer cells a broad spectrum of biochemical and biophysical cues that mimic the in vivo extracellular matrix(ECM).Additionally,such materials have mechanical adaptability,micro-structure interconnectivity,and inherent bioactivity,making them ideal for the design of living implants for specific applications in TE and regenerative medicine.This paper provides an overview for recent progress of biomimetic natural biomaterials(BNBMs),including advances in their preparation,functionality,potential applications and future challenges.We highlight recent advances in the fabrication of BNBMs and outline general strategies for functionalizing and tailoring the BNBMs with various biological and physicochemical characteristics of native ECM.Moreover,we offer an overview of recent key advances in the functionalization and applications of versatile BNBMs for TE applications.Finally,we conclude by offering our perspective on open challenges and future developments in this rapidly-evolving field. 展开更多
关键词 Biomimic SCAFFOLD BIOSYNTHESIS natural biomaterial Tissue engineering
下载PDF
Facile synthesis of hierarchical NaX zeolite from natural kaolinite for efficient Knoevenagel condensation 被引量:2
5
作者 Wen Xiao Peng Dong +6 位作者 Chan Wang Jingdong Xu Tiesen Li Haibo Zhu Tinghai Wang Renwei Xu Yuanyuan Yue 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第1期75-84,共10页
Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals.However,the micropores of zeolites impose diffusion limitations on bulky molecules,greatly reducing the catalytic efficien... Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals.However,the micropores of zeolites impose diffusion limitations on bulky molecules,greatly reducing the catalytic efficiency.Herein,we explore an economic and environmentally friendly method for synthesizing hierarchical NaX zeolite that exhibits improved catalytic performance in the Knoevenagel condensation reaction for producing the useful fine chemical 2-cyano-3-phenylacrylate.The synthesis was achieved via a low-temperature activation of kaolinite and subsequent in-situ transformation strategy without any template or seed.Systematic characterizations reveal that the synthesized NaX zeolite has both intercrystalline and intra-crystalline mesopores,smaller crystal size,and larger external specific surface area compared to commercial NaX zeolite.Detailed mechanism investigations show that the inter-crystalline mesopores are generated by stacking smaller crystals formed from in-situ crystallization of the depolymerized kaolinite,and the intra-crystalline mesopores are inherited from the pores in the depolymerized kaolinite.This synthesis strategy provides an energy-saving and effective way to construct hierarchical zeolites,which may gain wide applications in fine chemical manufacturing. 展开更多
关键词 Hierarchical NaX zeolite Template-free synthesis natural kaolinite Knoevenagel condensation
下载PDF
Genetic and epigenetic targets of natural dietary compounds as anti-Alzheimer's agents 被引量:1
6
作者 Willian Orlando Castillo-Ordoñez Nohelia Cajas-Salazar Mayra Alejandra Velasco-Reyes 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第4期846-854,共9页
Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older adults.Pathogenic factors,such as oxidative stress,an increase in acetylcholinester... Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older adults.Pathogenic factors,such as oxidative stress,an increase in acetylcholinesterase activity,mitochondrial dysfunction,genotoxicity,and neuroinflammation are present in this syndrome,which leads to neurodegeneration.Neurodegenerative pathologies such as Alzheimer’s disease are considered late-onset diseases caused by the complex combination of genetic,epigenetic,and environmental factors.There are two main types of Alzheimer’s disease,known as familial Alzheimer’s disease(onset<65 years)and late-onset or sporadic Alzheimer’s disease(onset≥65 years).Patients with familial Alzheimer’s disease inherit the disease due to rare mutations on the amyloid precursor protein(APP),presenilin 1 and 2(PSEN1 and PSEN2)genes in an autosomaldominantly fashion with closely 100%penetrance.In contrast,a different picture seems to emerge for sporadic Alzheimer’s disease,which exhibits numerous non-Mendelian anomalies suggesting an epigenetic component in its etiology.Importantly,the fundamental pathophysiological mechanisms driving Alzheimer’s disease are interfaced with epigenetic dysregulation.However,the dynamic nature of epigenetics seems to open up new avenues and hope in regenerative neurogenesis to improve brain repair in Alzheimer’s disease or following injury or stroke in humans.In recent years,there has been an increase in interest in using natural products for the treatment of neurodegenerative illnesses such as Alzheimer’s disease.Through epigenetic mechanisms,such as DNA methylation,non-coding RNAs,histone modification,and chromatin conformation regulation,natural compounds appear to exert neuroprotective effects.While we do not purport to cover every in this work,we do attempt to illustrate how various phytochemical compounds regulate the epigenetic effects of a few Alzheimer’s disease-related genes. 展开更多
关键词 Alzheimer’s disease EPIGENETICS genes METHYLATION natural products
下载PDF
Natural Disaster Risk Monitoring for Immovable Cultural Relics Based on Digital Twin 被引量:1
7
作者 LI Bolun DONG Youqiang +2 位作者 QIAO Yunfei HOU Miaole WEN Caihuan 《Journal of Geodesy and Geoinformation Science》 CSCD 2024年第1期90-104,共15页
Natural disaster risk monitoring is an important task for disaster prevention and reduction.In the case of immovable cultural relics,however,the feedback mechanism,risk factors,monitoring logic,and monitoring indicato... Natural disaster risk monitoring is an important task for disaster prevention and reduction.In the case of immovable cultural relics,however,the feedback mechanism,risk factors,monitoring logic,and monitoring indicators of natural disaster risk monitoring are complex.How to achieve intelligent perception and monitoring of natural disaster risk for immovable cultural relics has always been a focus and a challenge for researchers.Based on the analysis of the concepts and issues related to the natural disaster risk of immovable cultural relics,this paper proposes a framework for natural disaster risk monitoring for immovable cultural relics based on the digital twin.This framework focuses on risk monitoring,including the physical entities of natural disaster risk for immovable cultural relics,monitoring indicators,and virtual entity construction.A platform for monitoring the natural disaster risk of immovable cultural relics is proposed.Using the Puzhou Ancient City Site as a test bed,the proposed concept can be used for monitoring the natural disaster risk of immovable cultural relics at different scales. 展开更多
关键词 immovable cultural relics natural disaster risk digital twin risk monitoring
下载PDF
Numerical analysis of downward progressive landslides in long natural slopes with sensitive clay 被引量:1
8
作者 Yujia Zhang Xue Zhang +2 位作者 Xifan Li Aindra Lingden Jingjing Meng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期3937-3950,共14页
Landslides occurring in sensitive clay often result in widespread destruction,posing a significant risk to human lives and property due to the substantial decrease in undrained shear strength during deformation.Assess... Landslides occurring in sensitive clay often result in widespread destruction,posing a significant risk to human lives and property due to the substantial decrease in undrained shear strength during deformation.Assessing the consequences of these landslides is challenging and necessitates robust numerical methods to comprehensively investigate their failure mechanisms.While studies have extensively explored upward progressive landslides in sensitive clays,understanding downward progressive cases remains limited.In this study,we utilised the nodal integration-based particle finite element method(NPFEM)with a nonlinear strain-softening model to analyse downward progressive landslides in sensitive clay on elongated slopes,induced by surcharge loads near the crest.We focused on elucidating the underlying failure mechanisms and evaluating the effects of different soil parameters and strainsoftening characteristics.The simulation results revealed the typical pattern for downward landslides,which typically start with a localised failure in proximity to the surcharge loads,followed by a combination of different types of failure mechanisms,including single flow slides,translational progressive landslides,progressive flow slides,and spread failures.Additionally,inclined shear bands occur within spread failures,often adopting distinctive ploughing patterns characterised by triangular shapes.The sensitive clay thickness at the base,the clay strength gradient,the sensitivity,and the softening rate significantly influence the failure mechanisms and the extent of diffused displacement.Remarkably,some of these effects mirror those observed in upward progressive landslides,underscoring the interconnectedness of these phenomena.This study contributes valuable insights into the complex dynamics of sensitive clay landslides,shedding light on the intricate interplay of factors governing their behaviour and progression. 展开更多
关键词 Sensitive clay landslides Long natural slopes Translational progressive failure Flow slides Spread Nodal integration-based particle finite element method(N-PFEM)
下载PDF
Natural rubber latex as a potential additive for water-based drilling fluids
9
作者 Jun Yang Guan-Cheng Jiang +4 位作者 Jing-Tian Yi Yin-Bo He Li-Li Yang Teng-Fei Dong Guo-Shuai Wang 《Petroleum Science》 SCIE EI CAS CSCD 2024年第4期2677-2687,共11页
The environmental hazards and"carbon footprint"of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and ... The environmental hazards and"carbon footprint"of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and animals.This paper explored for the first time the interaction mechanism between natural rubber latex(NRL)and bentonite suspensions(BTs)through a series of characterization experiments,as well as the potential applications in water-based drilling fluids(WBDF).The gel viscoelasticity experiments showed that NRL could decrease the consistency coefficient(k)and flow index(n)of BTs,and enhance the shear thinning performance of BTs as pseudo-plastic fluids.In addition,0.5 w/v%NRL not only increased the critical yield stress and strengthened the structural strength between the bentonite particles,but also facilitated the compatibility of pressure loss and flow efficiency.The evaluation of colloidal stability and WBDF performance indicated that NRL particles could promote the hydration and charge stability on the surface of BTs particles,and optimize the particle size distribution and flow resistance of WBDF under the"intercalation-exfoliation-encapsulation"synergistic interaction.Moreover,NRL can improve the rheological properties of WBDF at high temperatures(<150.C),and form a dense blocking layer by bridging and sealing the pores and cracks of the filter cake,which ultimately reduces the permeability of the cake and the filtration loss of WBDF. 展开更多
关键词 natural materials Water-based drilling fluids natural rubber latex Bentonite suspensions Filtration loss
下载PDF
DNA G-Quadruplexes as Targets for Natural Product Drug Discovery
10
作者 Kai-Bo Wang Yingying Wang +1 位作者 Jonathan Dickerhoff Danzhou Yang 《Engineering》 SCIE EI CAS CSCD 2024年第7期39-51,共13页
DNA guanine(G)-quadruplexes(G4s)are unique secondary structures formed by two or more stacked Gtetrads in G-rich DNA sequences.These structures have been found to play a crucial role in highly transcribed genes,especi... DNA guanine(G)-quadruplexes(G4s)are unique secondary structures formed by two or more stacked Gtetrads in G-rich DNA sequences.These structures have been found to play a crucial role in highly transcribed genes,especially in cancer-related oncogenes,making them attractive targets for cancer therapeutics.Significantly,targeting oncogene promoter G4 structures has emerged as a promising strategy to address the challenge of undruggable and drug-resistant proteins,such as MYC,BCL2,KRAS,and EGFR.Natural products have long been an important source of drug discovery,particularly in the fields of cancer and infectious diseases.Noteworthy progress has recently been made in the discovery of naturally occurring DNA G4-targeting drugs.Numerous DNA G4s,such as MYC-G4,BCL2-G4,KRAS-G4,PDGFR-b-G4,VEGF-G4,and telomeric-G4,have been identified as potential targets of natural products,including berberine,telomestatin,quindoline,sanguinarine,isaindigotone,and many others.Herein,we summarize and evaluate recent advancements in natural and nature-derived DNA G4 binders,focusing on understanding the structural recognition of DNA G4s by small molecules derived from nature.We also discuss the challenges and opportunities associated with developing drugs that target DNA G4s. 展开更多
关键词 G-QUADRUPLEX natural products ALKALOIDS CANCER PROMOTER
下载PDF
Research on Intergenerational Writing in Contemporary German Immigrant Literature
11
作者 ZHOU Lei 《Sino-US English Teaching》 2024年第7期303-308,共6页
With the deepening of globalization,immigration and pluralism have become increasingly common social phenomena.The research of the resulting immigrant literature is an important way to understand the mental journey of... With the deepening of globalization,immigration and pluralism have become increasingly common social phenomena.The research of the resulting immigrant literature is an important way to understand the mental journey of immigrant groups and their construction of cultural identity.In the German-speaking area,immigrant literature has gradually taken center stage over the years,becoming an important part of the German language literature,and immigrant writers have also frequently won various literary prizes,which can be described as particularly dazzling.Meanwhile,generations of writers have been thinking about and exploring the intergenerational relationships and differences among immigrant groups in the context of their own experiences.This paper will focus on some outstanding immigrant writers and discuss the intergenerational writing in immigrant literature by means of their works. 展开更多
关键词 immigrant literature immigrant writers intergenerational writing
下载PDF
Natural Silicate as a Solid Support for the Calix[4]Thiophosphorus Derivative for Removal Mercury (II), as Picrate from Water
12
作者 Walther B. Aparicio-Aragon Tania Deza-Ramos 《Advances in Chemical Engineering and Science》 CAS 2024年第2期74-83,共10页
Currently a technique widely used for gold extraction is mercury by amalgamation technique, the tailing produced pollutes water of all kinds, so it is necessary to develop a form of selective mitigation, for which it ... Currently a technique widely used for gold extraction is mercury by amalgamation technique, the tailing produced pollutes water of all kinds, so it is necessary to develop a form of selective mitigation, for which it is necessary to use complexing agents based on calixarene functionalized with mercury sequestering agents. These are immobilized by adding supports based on natural silica to form polymers and make them insoluble in all types of solvents, so that they can be used as an extractor and at the same time regenerate to their original properties for continuous reuse. 展开更多
关键词 Extraction AMALGAMATION Polymer natural Silicate CALIXARENE
下载PDF
Stand dynamics of old-growth hemlock forests in central Bhutan are shaped by natural disturbances
13
作者 Karma Tenzin Craig R.Nitschke +3 位作者 Kathryn J.Allen Raphael Trouve Thiet V.Nguyen Patrick J.Baker 《Forest Ecosystems》 SCIE CSCD 2024年第4期434-447,共14页
Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future changes.In this study,dendrochronological metho... Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future changes.In this study,dendrochronological methods were applied to uncover the disturbance history of old-growth hemlock-dominated forests in central Bhutan.Analysis of tree-ring samples from two old-growth hemlock stands,located in two different topographic settings,identified the importance of gap-phase dynamics in facilitating recruitment and growth releases and producing complex,multi-aged structure s over time.One site showed evidence of a near stand-replacing disturbance in the late 1700s,while the other showed no evide nce of high-severity disturbance at any time over the last 400 years.At both sites low-to medium-severity disturbances,some of which appear to be associated with cyclones originating in the Bay of Bengal,dominated the disturbance regime.The hemlock stands exhibited a significant positive association between cyclone occurrence and growth release events and between recruitment pulses and growth release events.From 1800 to 1970 there was an increase in recruitment of angiosperm tree species at most sites and a corresponding decline in conifer recruitment.Over the past 50 years there has been little new recruitment;this may be due to light limitation in the understory from shade-tolerant angiosperms and bamboo in the lower strata of these stands.Significant variations in disturbance dynamics and recruitment were observed across the study sites,suggesting that other factors,such as topography and climate,may be influencing long-term stand development patterns.This study highlights the complex interplay between historical disturbance regimes and tree recruitment in shaping the age and size structures of old-growth hemlock forests in central Bhutan.It also provides new insights into the dynamics of these forests that can be used to support effective forest conservation and management in the future. 展开更多
关键词 Forest structure Hemlock forest HIMALAYA natural disturbance
下载PDF
Energy Design and Optimization of Greenhouse by Natural Convection
14
作者 H.Benzzine H.Labrim +3 位作者 Aouatif Saad Y.Achour D.Zejli R.El Bouayadi 《Fluid Dynamics & Materials Processing》 EI 2024年第8期1903-1913,共11页
This study addresses the pressing need for energy-efficient greenhouse management by focusing on the innovative application of natural ventilation.The primary objective of this study is to evaluate various ventilation... This study addresses the pressing need for energy-efficient greenhouse management by focusing on the innovative application of natural ventilation.The primary objective of this study is to evaluate various ventilation strategies to enhance energy efficiency and optimize crop production in agricultural greenhouses.Employing advanced numerical simulation tools,the study conducts a comprehensive assessment of natural ventilation’s effectiveness under real-world conditions.The results underscore the crucial role of the stack effect and strategic window positioning in greenhouse cooling,providing valuable insights for greenhouse designers.Our findings shed light on the significant benefits of optimized ventilation and also offer practical implications for improving greenhouse design,ensuring sustainable and efficient agricultural practices.The study demonstrated energy savings in cooling from November to April,with a maximum saving of 680 kWh in March,indicating the effectiveness of strategically positioning windows to leverage the stack effect.This approach enhances plant growth and reduces the need for costly cooling systems,thereby improving overall energy efficiency and lowering operational expenses. 展开更多
关键词 ENERGY GREENHOUSE COOLING natural ventilation SIMULATION TEMPERATURE
下载PDF
Effect of artificial natural light on the development of myopia among primary school-age children in China:a three-year longitudinal study
15
作者 Hui-Min Cai Meng-Yan Li +6 位作者 Yi Cao Yu-Lin Wu Ming Liang Yu-Shi Chen Bi-Kun Xian Yu-Juan Huang Xiang-Bin Kong 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第5期924-931,共8页
AIM:To assess the efficacy of artificial natural light in preventing incident myopia in primary school-age children.METHODS:This is a prospective,randomized control,intervention study.A total of 1840 students from 39 ... AIM:To assess the efficacy of artificial natural light in preventing incident myopia in primary school-age children.METHODS:This is a prospective,randomized control,intervention study.A total of 1840 students from 39 classes in 4 primary schools in Foshan participated in this study.The whole randomization method was adopted to include classes as a group according to 1:1 randomized control.Classrooms in the control group were illuminated by usual light,and classrooms in the intervention group were illuminated by artificial natural light.All students received uncorrected visual acuity and best-corrected visual acuity measurement,non-cycloplegic autorefraction,ocular biometric examination,slit lamp and strabismus examination.Three-year follow-up,the students underwent same procedures.Myopia was defined as spherical equivalent refraction≤-0.50 D and uncorrected visual acuity<20/20.RESULTS:There were 894 students in the control group and 946 students in the intervention group with a mean±SD age of 7.50±0.53y.The three-year cumulative incidence rate of myopia was 26.4%(207 incident cases among 784 eligible participants at baseline)in the control group and 21.2%(164 incident cases among 774 eligible participants at baseline)in the intervention group[difference of 5.2%(95%CI,3.7%to 10.1%);P=0.035].There was also a significant difference in the three-year change in spherical equivalent refraction for the control group(-0.81 D)compared with the intervention group[-0.63 D;difference of 0.18 D(95%CI,0.08 to 0.28 D);P<0.001].Elongation of axial length was significantly different between in the control group(0.77 mm)and the intervention group[0.72 mm;difference of 0.05 mm(95%CI,0.01 to 0.09 mm);P=0.003].CONCLUSION:Artificial natural light in the classroom of primary schools can result in reducing incidence rate of myopia during a period of three years. 展开更多
关键词 MYOPIA artificial natural light school-age children EFFICACY
下载PDF
How topography and neighbor shape the fate of trees in subtropical forest restoration:Environmental filtering and resource competition drive natural regeneration
16
作者 Haonan Zhang Xingshuo Zhang +7 位作者 Yingying Lv Yanyan Ni Baokun Xu Xiangnan Han Xiao Cao Qingpei Yang Wanggu Xu Zhedong Qian 《Forest Ecosystems》 SCIE CSCD 2024年第1期73-86,共14页
The structure of plant communities at local scales depends on both the spatial heterogeneity of abiotic environmental factors and the biotic interactions within the community.However,although environmental filtering d... The structure of plant communities at local scales depends on both the spatial heterogeneity of abiotic environmental factors and the biotic interactions within the community.However,although environmental filtering due to microtopographic heterogeneity and resource competition among plants caused by spatial variation in tree density and size are considered to be very important in explaining the mechanisms of community assembly,their effects on the processes of individual mortality and recruitment in natural forest regeneration,as well as their relative contributions,are still poorly understood.To address this,we established a 12-ha permanent plot in a subtropical evergreen broad-leaved forest area and measured microtopographic variables such as elevation,slope,aspect,and terrain position index(TPI)using a total station.We monitored the individual mortality and recruitment in forest natural regeneration through repeated surveys at 5-year intervals.We fitted spatial covariance models to jointly use multiple factors from three groups of variables(microtopographic effect,neighborhood density effects,neighborhood size effects)as explanatory variables to analyze their roles in driving the mortality and recruitment of all individual and 12 dominant species in forest natural regeneration at the neighborhood scale.Our results show that:(1)In the crucial early stages of secondary forest restoration,natural regeneration is influenced by a synergy of environmental filtering,due to microtopographic heterogeneity,and resource competition among plants.(2)For distinct species responses,evergreen dominant species'mortality is largely explained by neighborhood effects,while deciduous species are more affected by topographic factors.Furthermore,the adverse effects of larger conspecific trees on younger trees indicate a pattern of competitive pressure leading to mortality among regenerating trees,such pattern emphasis the influence of parent trees on natural regeneration.(3)As trees grow,their interaction with these stressors evolves,suggesting a shift in their resource acquisition strategies and response to neighborhood effects and environmental factors.Despite these changes,the relative importance of topographic factors in determining survival and recruitment success remains constant.This research highlights the importance of considering both environmental and neighborhood effects in forest management,particularly in early secondary forest restoration. 展开更多
关键词 natural regeneration MICROTOPOGRAPHY Neighborhood effects Mortality and recruitment
下载PDF
Natural variation in the cytochrome c oxidase subunit 5B OsCOX5B regulates seed vigor by altering energy production in rice
17
作者 Chengwei Huang Zhijuan Ji +7 位作者 Qianqian Huang Liling Peng Wenwen Li Dandan Wang Zepeng Wu Jia Zhao Yongqi He Zhoufei Wang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第9期2898-2910,共13页
Seed vigor is a crucial trait for the direct seeding of rice.Here we examined the genetic regulation of seed vigor traits in rice,including germination index(GI)and germination potential(GP),using a genome-wide associ... Seed vigor is a crucial trait for the direct seeding of rice.Here we examined the genetic regulation of seed vigor traits in rice,including germination index(GI)and germination potential(GP),using a genome-wide association study approach.One major quantitative trait locus,qGI6/qGP6,was identified simultaneously for both GI and GP.The candidate gene encoding the cytochrome c oxidase subunit 5B(OsCOX5B)was validated for qGI6/qGP6.The disruption of OsCOX5B caused the vigor traits to be significantly lower in Oscox5b mutants than in the japonica Nipponbare wild type(WT).Gene co-expression analysis revealed that OsCOX5B influences seed vigor mainly by modulating the tricarboxylic acid cycle process.The glucose levels were significantly higher while the pyruvic acid and adenosine triphosphate levels were significantly lower in Oscox5b mutants than in WT during seed germination.The elite haplotype of OsCOX5B facilitates seed vigor by increasing its expression during seed germination.Thus,we propose that OsCOX5B is a potential target for the breeding of rice varieties with enhanced seed vigor for direct seeding. 展开更多
关键词 cytochrome c oxidase natural variation RICE seed vigor
下载PDF
Literature classification and its applications in condensed matter physics and materials science by natural language processing
18
作者 吴思远 朱天念 +5 位作者 涂思佳 肖睿娟 袁洁 吴泉生 李泓 翁红明 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期117-123,共7页
The exponential growth of literature is constraining researchers’access to comprehensive information in related fields.While natural language processing(NLP)may offer an effective solution to literature classificatio... The exponential growth of literature is constraining researchers’access to comprehensive information in related fields.While natural language processing(NLP)may offer an effective solution to literature classification,it remains hindered by the lack of labelled dataset.In this article,we introduce a novel method for generating literature classification models through semi-supervised learning,which can generate labelled dataset iteratively with limited human input.We apply this method to train NLP models for classifying literatures related to several research directions,i.e.,battery,superconductor,topological material,and artificial intelligence(AI)in materials science.The trained NLP‘battery’model applied on a larger dataset different from the training and testing dataset can achieve F1 score of 0.738,which indicates the accuracy and reliability of this scheme.Furthermore,our approach demonstrates that even with insufficient data,the not-well-trained model in the first few cycles can identify the relationships among different research fields and facilitate the discovery and understanding of interdisciplinary directions. 展开更多
关键词 natural language processing text mining materials science
下载PDF
New insights into the deposition of natural gas hydrate on pipeline surfaces:A molecular dynamics simulation study
19
作者 Jun Zhang Hai-Qiang Fu +7 位作者 Mu-Zhi Guo Zhao Wang Li-Wen Li Qi Yin You-Guo Yan Wei Wei Wei-Feng Han Jie Zhong 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期694-704,共11页
Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent N... Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces. 展开更多
关键词 DEPOSITION natural gas hydrate Pipelines Water affinity Adhesion strength
下载PDF
Natural Products Improve Organ Microcirculation Dysfunction Following Ischemia/Reperfusion-and Lipopolysaccharide-Induced Disturbances:Mechanistic and Therapeutic Views
20
作者 Jingyan Han Quan Li +6 位作者 Kai Sun Chunshui Pan Jian Liu Ping Huang Juan Feng Yanchen Liu Gerald A.Meininger 《Engineering》 SCIE EI CAS CSCD 2024年第7期77-99,共23页
Microcirculatory disturbances are complex processes caused by many factors,including abnormal vasomotor responses,decreased blood flow velocity,vascular endothelial cell injury,altered leukocyte and endothelial cell i... Microcirculatory disturbances are complex processes caused by many factors,including abnormal vasomotor responses,decreased blood flow velocity,vascular endothelial cell injury,altered leukocyte and endothelial cell interactions,plasma albumin leakage,microvascular hemorrhage,and thrombosis.These disturbances involve multiple mechanisms and interactions among mechanisms that can include energy metabolism,the mitochondrial respiratory chain,oxidative stress,inflammatory factors,adhesion molecules,the cytoskeleton,vascular endothelial cells,caveolae,cell junctions,the vascular basement membrane,neutrophils,monocytes,and platelets.In clinical practice,aside from drugs that target abnormal vasomotor responses and platelet adhesion,there continues to be a lack of multi-target drugs that can regulate the complex mechanistic links and interactions underlying microcirculatory disturbances.Natural products have demonstrated obvious positive therapeutic effects in treating ischemia/reperfusion(I/R)-and lipopolysaccharide(LPS)-induced microcirculatory disturbances.In recent years,numerous research papers on the improvement of microcirculatory function by natural products have been published in international journals.In 2008 and 2017,the first listed author of this review was invited to publish reviews in the journal of Pharmacology&Therapeutics on the improvement of microcirculatory disturbances and organ injury induced by I/R using Salvia miltiorrhiza ingredients and other natural components of compounded Chinese medicine,respectively.This review systematically summarizes the effects,targets of action,and mechanisms of natural products regarding improving I/R-and LPSinduced microcirculatory disturbances and tissue injury.Based on this summary,scientific proposals are suggested for the discovery of new drugs to improve microcirculatory disturbances in disease. 展开更多
关键词 ISCHEMIA/REPERFUSION LIPOPOLYSACCHARIDE natural products Leukocyte activation Hyperpermeability
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部