Based on the frequency of themes covered at the 35th International Geographical Congress(IGC)and the 2024 American Association of Geographers Annual Meeting(AAG-AM),we present an integrated analysis of current researc...Based on the frequency of themes covered at the 35th International Geographical Congress(IGC)and the 2024 American Association of Geographers Annual Meeting(AAG-AM),we present an integrated analysis of current research hotspots in geography.The interdisciplinary approach of geography in tackling global challenges,including climate change,urbanization,and sustainable development is highlighted.Hotspot analysis of the 35th IGC reveals the prominence of“Tourism,Leisure,and Global Change,”and“Urban Geography”as key themes,whereas the 2024 AAG-AM placed more emphasis on“GeoAI and Deep Learning,”and“Geospatial Data Science for Sustainability.”Frontier analysis,based on emerging research beyond the two conferences,highlights major critical issues being confronted by geographers,notably Earth’s surface systems,spatial patterns of human activities,intelligent remote sensing,climate change adaptation,biodiversity conservation,hazards and disaster risk,planetary boundaries,coupled human and natural systems,and global and regional sustainability.The analysis demonstrates that geographical research is becoming more diverse and systematic,and artificial intelligence technology is increasingly being harnessed.This not only reflects specific regional interests and priorities but also shows the dynamic development of geographical research and its important role in dealing with the challenges of the 21st century.展开更多
Objective:Based on the CNKI database,this study analyzes the current research status and hotspots of the Timing it Right(TIR)Theory in China,providing insights and references for its further development in the field o...Objective:Based on the CNKI database,this study analyzes the current research status and hotspots of the Timing it Right(TIR)Theory in China,providing insights and references for its further development in the field of nursing.Methods:Using bibliometric methods and Citespace software,this study conducts a statistical and visual analysis of publications on TIR Theory from CNKI,focusing on annual publication volumes,author collaboration networks,high-frequency keywords,and emergent terms.Results:The study statistically analyzed the time distribution and research hotspots of 117 relevant papers.The annual publication volume shows a gradual upward trend,though the overall volume remains low.High-frequency keywords such as“family nursing,”“quality of life,”“acute myocardial infarction,”and“stroke”form the core research themes.Conclusion:Research on TIR Theory in China’s nursing field is still in the exploratory stage,and its attention and emphasis need to be enhanced.As it aligns with modern medical models,its application scope in nursing is expanding,promoting the high-quality,scientific,and diversified development of nursing services in China.展开更多
With the improvement of people’s living standards and the demand for their own health,plant-derived cosmetics containing plant extracts or plant active ingredients are also more and more favored by consumers.In fact,...With the improvement of people’s living standards and the demand for their own health,plant-derived cosmetics containing plant extracts or plant active ingredients are also more and more favored by consumers.In fact,the research on plant-derived cosmetics has a history of centuries and even over 1,000 years both domestically and internationally.In order to further analyze the domestic and international research hotspots and future trends in the research field of plant-derived cosmetics,the relevant literatures from China National Knowledge Infrastructure(CNKI)database,Wanfang database,Vip database and Web of Science Core Collection(WoSCC)database from January 1994 to June 2024 were chosen as research objects in this paper.The authors,countries,research institutions and key words of the selected 1,415 Chinese papers and 1,927 English papers were visually analysed using the bibliometric software CiteSpace and VOSviewer.The results show that the number of publications shows an increasing trend;the communication and cooperation between core authors and between research institutions of the publicationare are both weak;the research hotspots mainly focus on natural plants,Chinese herbs,active ingredients,and whitening;and future research trends may include green synthesis,efficacy application,health and safety,etc.This study aims to grasp the hot spots and trends in the field of plant-derived cosmetics,and to provide ideas and references for the relevant research in China in the future.展开更多
China boasts over 10,000 native useful vascular plants(NUVPs),spanning eight families and serving twelve dis-tinct uses.Given the importance of NUVPs,widely-confirmed in-situ conservation policies,such as establishing...China boasts over 10,000 native useful vascular plants(NUVPs),spanning eight families and serving twelve dis-tinct uses.Given the importance of NUVPs,widely-confirmed in-situ conservation policies,such as establishing nature reserves,have been broadly implemented to protect them.However,the effectiveness of in-situ conser-vation efforts for NUVPs in China remains uncertain.Highlighting the importance of multi-family and multi-use plants,this research identified the spatial distribution pattern and diversity hotspots of NUVPs,evaluated the in-situ conservation effectiveness and provided the future conservation priority scheme.The results revealed that the spatial concentration of NUVPs is predominantly in the southwestern lowlands of China(<3,000 m),peaking around 109°E and 25°N.Importantly,diversity hotspots exhibited a significant spatial mismatch(over 80%)with the National Nature Reserve(NNR)network.Only about 17.7%and 13.3%of these hotspots are protected by NNR initiatives for endemic and nonendemic species,respectively.Additionally,the proposed Plants Conserva-tion Effectiveness Index(PCEI)proved more representative in addressing the two main crises faced by the studied species-species loss and human pressure,and found a decline in conservation effectiveness as the number of uses increased.Finally,future conservation priorities based on the PCEI highlight the Nanling Mountains,Heng-duan Mountains,Jiuwandashan,and Qilian Mountains as highly prioritized regions requiring focused efforts to address the impacts of climate change.Conversely,in sparsely distributed regions experiencing increasing human pressure,it is imperative to mitigate the expanding human footprint.展开更多
In renewing tissues,mutations conferring selective advantage may result in clonal expansions1-4.In contrast to somatic tissues,mutations driving clonal expansions in spermatogonia(CES)are also transmitted to the next ...In renewing tissues,mutations conferring selective advantage may result in clonal expansions1-4.In contrast to somatic tissues,mutations driving clonal expansions in spermatogonia(CES)are also transmitted to the next generation.This results in an effective increase of de novo mutation rate for CES drivers5-8.CES was originally discovered through extreme recurrence of de novo mutations causing Apert syndrome5.Here,we develop a systematic approach to discover CES drivers as hotspots of human de novo mutation.Our analysis of 54,715 trios ascertained for rare conditions9-13,6,065 control trios12,14-19 and population variation from 807,162 mostly healthy individuals20 identifies genes manifesting rates of de novo mutations inconsistent with plausible models of disease ascertainment.We propose 23 genes hypermutable at loss-of-function(LoF)sites as candidate CES drivers.An extra 17 genes feature hypermutable missense mutations at individual positions,suggesting CES acting through gain of function.CES increases the average mutation rate roughly 17-fold for LoF genes in both control trios and sperm and roughly 500-fold for pooled gain-of-function sites in sperm21.Positive selection in the male germline elevates the prevalence of genetic disorders and increases polymorphism levels,masking the effect of negative selection in human populations.展开更多
BACKGROUND Diabetic encephalopathy(DE)is a common and serious complication of diabetes that can cause death in many patients and significantly affects the lives of individuals and society.Multiple studies investigatin...BACKGROUND Diabetic encephalopathy(DE)is a common and serious complication of diabetes that can cause death in many patients and significantly affects the lives of individuals and society.Multiple studies investigating the pathogenesis of DE have been reported.However,few studies have focused on scientometric analysis of DE.AIM To analyze literature on DE using scientometrics to provide a comprehensive picture of research directions and progress in this field.METHODS We reviewed studies on DE or cognitive impairment published between 2004 and 2023.The latter were used to identify the most frequent keywords in the keyword analysis and explore the hotspots and trends of DE.RESULTS Scientometric analysis revealed 1308 research papers on DE,a number that increased annually over the past 20 years,and that the primary topics explored were domain distribution,knowledge structure,evolution,and emergence of research topics related to DE.The inducing factors,comorbidities,pathogenesis,treatment,and animal models of DE help clarify its occurrence,development,and treatment.An increasing number of studies on DE may be a result of the recent increase in patients with diabetes,unhealthy lifestyles,and unhealthy eating habits,which have aggravated the incidence of this disease.CONCLUSION We identified the main inducing factors and comorbidities of DE,though other complex factors undoubtedly increase social and economic burdens.These findings provide vital references for future studies.展开更多
BACKGROUND The lack of specific symptoms of gastric cancer(GC)causes great challenges in its early diagnosis.Thus it is essential to identify the risk factors for early diagnosis and treatment of GC and to improve the...BACKGROUND The lack of specific symptoms of gastric cancer(GC)causes great challenges in its early diagnosis.Thus it is essential to identify the risk factors for early diagnosis and treatment of GC and to improve the survival rates.AIM To assist physicians in identifying changes in the output of publications and research hotspots related to risk factors for GC,constructing a list of key risk factors,and providing a reference for early identification of patients at high risk for GC.METHODS Research articles on risk factors for GC were searched in the Web of Science core collection,and relevant information was extracted after screening.The literature was analyzed using Microsoft Excel 2019,CiteSpace V,and VOSviewer 1.6.18.RESULTS A total of 2514 papers from 72 countries and 2507 research institutions were retrieved.China(n=1061),National Cancer Center(n=138),and Shoichiro Tsugane(n=36)were the most productive country,institution,or author,respectively.The research hotspots in the study of risk factors for GC are summarized in four areas,namely:Helicobacter pylori(H.pylori)infection,single nucleotide polymorphism,bio-diagnostic markers,and GC risk prediction models.CONCLUSION In this study,we found that H.pylori infection is the most significant risk factor for GC;single-nucleotide polymorphism(SNP)is the most dominant genetic factor for GC;bio-diagnostic markers are the most promising diagnostic modality for GC.GC risk prediction models are the latest current research hotspot.We conclude that the most important risk factors for the development of GC are H.pylori infection,SNP,smoking,diet,and alcohol.展开更多
BACKGROUND Cognitive impairment,which manifests as a limited deterioration of specific functions associated with a particular disease,can lead to a general deterioration of the patient’s standard of living.Transcrani...BACKGROUND Cognitive impairment,which manifests as a limited deterioration of specific functions associated with a particular disease,can lead to a general deterioration of the patient’s standard of living.Transcranial magnetic stimulation,a noninvasive neuromodulation technique,is frequently employed to treat cognitive impairment in neuropsychiatric disorders.AIM To analyzed the state of international research on neuromodulation methods for treating cognitive impairment between 2014 and 2023,with the aim of exploring the state of research worldwide and the most recent developments in this particular area.METHODS Articles and reviews pertaining to neuromodulation methods for cognitive impairment were examined using the web of science database between January 2014 and December 2023.Publications,nations,organizations,writers,journals,citations,and keywords data from the identified studies were systematically analyzed using the CiteSpace 6.3.R1 software.RESULTS A total of 2371 documents with 11750 authors and 9461 institutions,with some cooccurrences,were retrieved.The quantity of yearly publications is showing an increasing trend.The United States and China have emerged as important contributors.Among the institutes,Harvard University had the highest number of publications,while Rossi S an author who is frequently cited.Initially,the primary keywords included human motor cortex,placebo-controlled trials,and serotonin reuptake inhibitors.However,the emphasis gradually moved to substance use disorders,supplementary motor areas,neural mechanisms,and exercise.CONCLUSION The use of neuromodulation techniques to treat cognitive impairment has drawn interest from academics all around the world.This study revealed hotspots and new trends in the research of transcranial magnetic stimulation as a cognitive impairment rehabilitation treatment.These findings are hold significant potential to guide further research and thus promote transcranial magnetic stimulation as a treatment method for cognitive impairment.展开更多
BACKGROUND The transjugular intrahepatic portosystemic shunt(TIPS)is an important technique for treating complications related to portal hypertension in patients with cirrhosis,and the number of publications in the TI...BACKGROUND The transjugular intrahepatic portosystemic shunt(TIPS)is an important technique for treating complications related to portal hypertension in patients with cirrhosis,and the number of publications in the TIPS field continues to rise.AIM To facilitate an understanding of the research status and hotspots in the field of TIPS using CiteSpace bibliometric analysis.METHODS CiteSpace is a software that depicts the strength of relationships through graphics and connections with diverse functionalities and can be used to analyze the status and hotspots of areas of research.Articles on TIPS in the Web of Science Core Collection were retrieved,and CiteSpace software was used to visualize and analyze the number of publications,journals,countries,institutions,authors,keywords,and citations.RESULTS A total of 985 relevant documents were included in the analysis.From January 2013 to December 2022,the number of publications increased annually.The journal,institution,and author with the greatest number of publications in the field of TIPS are the Journal of Vascular and Interventional Radiology,the University of Bonn,and Jonel Trebicka,respectively.The main keywords used in this field are“transjugular intrahepatic portosystemic shunt”,“portal hypertension”,“cirrhosis”,“management”,“stent”,“hepatic encephalopathy”,“refractory ascite”,“survival”,“risk”,and“variceal bleeding”.The greatest obstacle to TIPS placement is currently the occurrence of hepatic encephalopathy.The research hotspots are the mechanism,risk factors,management,and control of hepatic encephalopathy.CONCLUSION This bibliometric analysis reported the research status and hotspots of TIPS.Research on postoperative hepatic encephalopathy is the research hotspot in this field.展开更多
Purpose:To explore the status of current global research,trends and hotspots in the field of lupus retinopathy(LR).Methods:Publications related to LR from 2003 to 2022 were extracted from the Web of Science Core Colle...Purpose:To explore the status of current global research,trends and hotspots in the field of lupus retinopathy(LR).Methods:Publications related to LR from 2003 to 2022 were extracted from the Web of Science Core Collection(WOSCC).Citespace 6.2.R4 software was used to analyze the raw data.Bibliometric parameters such as publication quality,countries,authors,international cooperation,and keywords were taken into account.Results:A total of 315 publications were retrieved.The annual research output has increased significantly since 2010,especially since 2017.Marmor MF,Lee BR,and Melles RB contributed the highest number of articles published on LR.The top three publishing countries were the USA,China,and UK.Stanford University,Hanyang University,and Harvard Medical School were the top three producing institutions in the world for LR research.The top ten commonly used keywords include the following:systemic lupus erythematosus,retinopathy,retinal toxicity,antimalarial,hydroxychloroquine,optical coherence tomography,antiphospholipid syndrome,microvascular,optic neuritis,optical coherence tomography angiography.The keywords"optical coherence tomography angiography"and"vessel density"have exploded in recent years.Conclusion:By analyzing the current body of LR literature,specific global trends and hotspots for LR research were identified,presenting valuable information to track cutting-edge progress and for future cooperation between various authors and institutions.展开更多
Pathophysiology is a science that deeply explores the occurrence and development of diseases,studies the mechanisms behind the final results,and integrates knowledge from multiple disciplines such as physiology,bioche...Pathophysiology is a science that deeply explores the occurrence and development of diseases,studies the mechanisms behind the final results,and integrates knowledge from multiple disciplines such as physiology,biochemistry,and immunology.The core lies in revealing the pathological and physiological changes during the disease process and analyzing the fundamental principles.In the medical education system,pathophysiology is an integral part of the foundational curriculum,serving as a bridge between basic medicine and clinical medicine.By studying pathophysiology,students can comprehensively understand the initial causes of diseases,pathological processes,and functional metabolic changes of the body under disease conditions.This discipline is also committed to cultivating students’systematic thinking,critical analysis skills,and problem-solving abilities,comprehensively enhancing their overall quality,making them more competitive and adaptable in the medical field.展开更多
The Yangtze River Watershed in China is a climate change hotspot featuring strong spatial and temporal variability;hence, it poses a certain threat to social development. Identifying the characteristics of and regions...The Yangtze River Watershed in China is a climate change hotspot featuring strong spatial and temporal variability;hence, it poses a certain threat to social development. Identifying the characteristics of and regions vulnerable to climate change is significantly important for formulating adaptive countermeasures. However, with regard to the Yangtze River Watershed, there is currently a lack of research on these aspects from the perspective of natural and anthropogenic factors. To address this issue, in this study, based on the temperature and precipitation records from 717 meteorological stations, the RClim Dex and random forest models were used to assess the spatiotemporal characteristics of climate change and identify mainly the natural and anthropogenic factors influencing climate change hotspots in the Yangtze River Watershed for the period 1958-2017. The results indicated a significant increasing trend in temperature, a trend of wet and dry polarization in the annual precipitation, and that the number of temperature indices with significant variations was 2.8 times greater than that of precipitation indices. Significant differences were also noted in the responses of the climate change characteristics of the sub-basins to anthropogenic and natural factors;the delta plain of the Yangtze River estuary exhibited the most significant climate changes, where 88.89% of the extreme climate indices varied considerably. Furthermore, the characteristics that were similar among the identified hotpots, including human activities(higher Gross Domestic Product and construction land proportions) and natural factors(high altitudes and large proportions of grassland and water bodies), were positively correlated with the rapid climate warming.展开更多
The electrocardiogram （ECG） has broad applications in clinical diagnosis and prognosis of cardiovascular disease. Many researchers have contributed to its progressive development. To commemorate those pioneers, and ...The electrocardiogram （ECG） has broad applications in clinical diagnosis and prognosis of cardiovascular disease. Many researchers have contributed to its progressive development. To commemorate those pioneers, and to better study and promote the use of ECG, we reviewed and present here a systematic introduction about the history, hotspots, and trends of ECG. In the historical part, information including the invention, improvement, and extensive applications of ECG, such as in long QT syndrome （LQTS）, angina, and myocardial infarction （MI）, are chronologi- cally presented. New technologies and applications from the 1990s are also introduced. In the second part, we use the bibliometric analysis me- thod to analyze the hotspots in the field of ECG-related research. By using total citations and year-specific total citations as our main criteria, four key hotspots in ECG-related research were identified from 11 articles, including atrial fibrillation, LQTS, angina and MI, and heart rate variability. Recent studies in those four areas are also reported. In the final part, we discuss the future trends concerning ECG-related research. The authors believe that improvement of the ECG instrumentation, big data mining for ECG, and the accuracy of diagnosis and application will be areas of continuous concern.展开更多
The hotspot recognition algorithm is proposed based on a potential collision in order to study the aircraft taxi conflicts in large airports.The spatial and temporal distribution characteristics of hotspots are analyz...The hotspot recognition algorithm is proposed based on a potential collision in order to study the aircraft taxi conflicts in large airports.The spatial and temporal distribution characteristics of hotspots are analyzed based on the risk assessment model of hotspot constructed in this paper.Firstly,approaches for monitoring of the aerodrome movement were compared.The hotspot recognition algorithm taken into account of whether aircrafts'taxi track has spatial and temporal overlap based on the aerodrome surveillance radar(ASR)data was presented,by identifying the hotspots through analyzing whether the aircrafts'time of entering and exiting the same taxiway is overlap or not,and the heading difference and distance of the two aircrafts satisfy the specified threshold constraint condition.Then,the ASR data were divided into several parts,and then airport hotspots were recognized and the spatial and temporal distribution characteristics were analyzed.The risk assessment model of airport safety hotspots was constructed which is taken into account of the conflict probability and its severity consequence.Finally,based on the risk grade assessment criteria and hotspots'risk value,the risk grade ranking of hotspot in one airport of China was evaluated and designated.According to the result,the spatial and temporal distribution characteristics of airport hotspots were varied with the variation of airport traffic flow and operational mode of runway,which shows that the hotspots have the characteristics of dynamic periodicity and diurnal variation.And the risk assessment results were consistent with experts'opinions and actual operation condition,which verified the rationality of the hotspot recognition algorithm,risk assessment model as well as the risk grade ranking criteria.展开更多
Members of the aquatic plant genus Aponogeton are widely used commercially in aquariums because of their variable leaf shape and unique inflorescences.However,due to extensive similarity between species in this genus,...Members of the aquatic plant genus Aponogeton are widely used commercially in aquariums because of their variable leaf shape and unique inflorescences.However,due to extensive similarity between species in this genus,morphological characters are generally inadequate for taxonomic classification.Currently,molecular makers available for taxonomic and phylogenetic studies of Aponogeton are limited.One approach to clarifying relationships between species in these complex groups is to use divergence hotspot regions within the genome.Here,we sequenced and analyzed the plastomes of five Aponogeton species collected from China,Zambia,and Kenya,and subsequently screened these plastomes for divergent DNA hotspots.The five plastomes are circular structures with sizes ranging from 154,167 bp to 154,860 bp.The Large and the Small Single Copies are separated by two Inverted Repeats.One hundred and thirteen unique genes were identified including 79 protein-coding,30 tRNA,and four rRNA genes.We found that the most abundant repeats in all but one species were mononucleotide repeats(A/T)and that there were 23 potential RNA ending sites.Interestingly,a^3 kb inversion,which includes the accD gene,was detected within the Asian species of Aponogeton.The inversion may be related to more frequent exchanges between this region and the nuclear genome.Furthermore,we detected mutational hotspot sites among the five Aponogeton species.Three of these hotspots are intergenic spacer regions(accD-psaI,rbcL-accD and trnH-GUG-psbA)that might be suitable for use as barcodes to resolve intra-generic relationships.We also identified four highly variable protein-coding genes(ccsA,rpl22,rps16 and ycf1)may be used as barcodes to resolve the higher-level phylogenies.Our study will provide valuable molecular resources for the taxonomic and phylogenomic study of the complex genus Aponogeton.展开更多
Objective: To analyze clinical psychological nursing research hotspots in China and variation trends in order to provide reference points on the current state of development of clinical psychological nursing and futur...Objective: To analyze clinical psychological nursing research hotspots in China and variation trends in order to provide reference points on the current state of development of clinical psychological nursing and future research hotspots.Method: Clinical psychological nursing research literature sourced from Wanfang Data for the three periods of 2007-2009, 2010-2012, and 2013-2015 were selected as the research sample. A bibliographic co-occurrence analysis system(BICOMB software) was used to perform keyword word frequency analysis and generate a keyword co-occurrence matrix. In addition, Ucinet software's Netdraw tool was used to create visualized network diagrams.Results: A total of 27890 articles were retrieved, and word frequency analysis revealed that the highestfrequency keywords consisted of anxiety, depression, the elderly, expectant women, coronary heart disease, diabetes, breast cancer, perioperative period, quality of life, and psychological intervention.Research hotspot analysis revealed that consistent hotspots comprised anxiety, depression, health education, and perioperative period; expectant women became a hotspot during 2010-2012, and quality of life and efficacy became hotspots during 2013-2015.Conclusions: In addition to the care process, clinical psychological nursing research hotspots in China have increasingly included the effectiveness of psychological nursing and impact on patient quality of life. In addition, research hotspots have been influenced by the incidence of illnesses and people's health consciousness.展开更多
We examined the scale impacts on spatial hot and cold spots of CPUE for Ommastrephes bartramii in the northwest Pacific Ocean. The original fishery data were tessellated to 18 spatial scales from 5′×5′ to 90′&...We examined the scale impacts on spatial hot and cold spots of CPUE for Ommastrephes bartramii in the northwest Pacific Ocean. The original fishery data were tessellated to 18 spatial scales from 5′×5′ to 90′×90′ with a scale interval of 5′ to identify the local clusters. The changes in location, boundaries, and statistics regarding the Getis-Ord Gi＊ hot and cold spots in response to the spatial scales were analyzed in detail. Several statistics including Min, mean, Max, SD, CV, skewness, kurtosis, first quartile（Q1）, median, third quartile（Q3）, area and centroid were calculated for spatial hot and cold spots. Scaling impacts were examined for the selected statistics using linear, logarithmic, exponential, power law and polynomial functions. Clear scaling relations were identified for Max, SD and kurtosis for both hot and cold spots. For the remaining statistics, either a difference of scale impacts was found between the two clusters, or no clear scaling relation was identified. Spatial scales coarser than 30′ are not recommended to identify the local spatial patterns of fisheries because the boundary and locations of hot and cold spots at a coarser scale are significantly different from those at the original scale.展开更多
The soils, tropical climate, and network of canals and rivers of southern Vietnam have created one of the most diverse tropical jungles and intensely cultivated landscapes of Southeast Asia. This paradise has a long h...The soils, tropical climate, and network of canals and rivers of southern Vietnam have created one of the most diverse tropical jungles and intensely cultivated landscapes of Southeast Asia. This paradise has a long history of numerous wars, foreign occupations, and most recently the Second Indochina War (aka the Vietnam War 1965-1972) which defoliated rain forests and ancient wetland mangroves and left behind contaminated soil and sediment hotspots. During this war, the United States (US) military sprayed 80 million liters of Agent Orange contaminated with the dioxin TCDD in a guerrilla war against communist insurgents. Agent Orange was a synthetic plant growth regulator comprised of equal amounts of two herbicides 2,4-dichloro phenoxyacetic acid C8H6Cl2O3 (2,4-D) and 2,4,5-trichlorophenoxyacetic acid C8H5Cl3O3 (2,4,5-T). TCDD, the dioxin, 2,3,7,8-tetrachlorodibenzodioxin (C12H4Cl4O2) was an unintended byproduct of the accelerated combustion process used in the manufacture of herbicides containing 2,4,5-T. Agent Orange has frequently been blamed for soil and sediment contamination and long-term human health problems;however, the true source of harm is the dioxin TCDD. Agent Orange has a short half-life of days and weeks after application to vegetation, and has not been found to persist, after 50 years, in the water or soils of southern Vietnam. However, the half-life of dioxin TCDD depends on where it is deposited and varies from 1 to 3 years on soil surfaces that have been fully exposed to sunlight, to as long as 20 to 50 years or more when buried in tropical subsoils, and more than 100 years in river and sea sediments. Dioxin TCDD was heavily concentrated in the US Air Force bases in Vietnam where the herbicides were stored, loaded on planes and helicopters for aerial spraying, and used extensively around military base perimeter fences as a security measure to prevent surprise attacks. Bien Hoa Air Force base, 40 km northeast of Ho Chi Minh City, continues to be one of the mega-hotspots where after 48 years the dioxin TCDD levels in fish and shrimp are still high and fishing is banned in ponds and lakes adjacent to the airbase. Although expensive, one of the most effective remediation to dioxin TCDD contaminated soils is incineration which is the recommended method of dioxin TCDD disposal.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.42430505,42201299)the Young Elite Scientists Sponsorship Program by CAST(Grant No.2023QNRC001).
文摘Based on the frequency of themes covered at the 35th International Geographical Congress(IGC)and the 2024 American Association of Geographers Annual Meeting(AAG-AM),we present an integrated analysis of current research hotspots in geography.The interdisciplinary approach of geography in tackling global challenges,including climate change,urbanization,and sustainable development is highlighted.Hotspot analysis of the 35th IGC reveals the prominence of“Tourism,Leisure,and Global Change,”and“Urban Geography”as key themes,whereas the 2024 AAG-AM placed more emphasis on“GeoAI and Deep Learning,”and“Geospatial Data Science for Sustainability.”Frontier analysis,based on emerging research beyond the two conferences,highlights major critical issues being confronted by geographers,notably Earth’s surface systems,spatial patterns of human activities,intelligent remote sensing,climate change adaptation,biodiversity conservation,hazards and disaster risk,planetary boundaries,coupled human and natural systems,and global and regional sustainability.The analysis demonstrates that geographical research is becoming more diverse and systematic,and artificial intelligence technology is increasingly being harnessed.This not only reflects specific regional interests and priorities but also shows the dynamic development of geographical research and its important role in dealing with the challenges of the 21st century.
文摘Objective:Based on the CNKI database,this study analyzes the current research status and hotspots of the Timing it Right(TIR)Theory in China,providing insights and references for its further development in the field of nursing.Methods:Using bibliometric methods and Citespace software,this study conducts a statistical and visual analysis of publications on TIR Theory from CNKI,focusing on annual publication volumes,author collaboration networks,high-frequency keywords,and emergent terms.Results:The study statistically analyzed the time distribution and research hotspots of 117 relevant papers.The annual publication volume shows a gradual upward trend,though the overall volume remains low.High-frequency keywords such as“family nursing,”“quality of life,”“acute myocardial infarction,”and“stroke”form the core research themes.Conclusion:Research on TIR Theory in China’s nursing field is still in the exploratory stage,and its attention and emphasis need to be enhanced.As it aligns with modern medical models,its application scope in nursing is expanding,promoting the high-quality,scientific,and diversified development of nursing services in China.
文摘With the improvement of people’s living standards and the demand for their own health,plant-derived cosmetics containing plant extracts or plant active ingredients are also more and more favored by consumers.In fact,the research on plant-derived cosmetics has a history of centuries and even over 1,000 years both domestically and internationally.In order to further analyze the domestic and international research hotspots and future trends in the research field of plant-derived cosmetics,the relevant literatures from China National Knowledge Infrastructure(CNKI)database,Wanfang database,Vip database and Web of Science Core Collection(WoSCC)database from January 1994 to June 2024 were chosen as research objects in this paper.The authors,countries,research institutions and key words of the selected 1,415 Chinese papers and 1,927 English papers were visually analysed using the bibliometric software CiteSpace and VOSviewer.The results show that the number of publications shows an increasing trend;the communication and cooperation between core authors and between research institutions of the publicationare are both weak;the research hotspots mainly focus on natural plants,Chinese herbs,active ingredients,and whitening;and future research trends may include green synthesis,efficacy application,health and safety,etc.This study aims to grasp the hot spots and trends in the field of plant-derived cosmetics,and to provide ideas and references for the relevant research in China in the future.
基金supported by the National Natural Science Foundation of China(Grant No.42330205)the Open Fund of State Key Labora-tory of Remote Sensing Science and Beijing Engineering Research Center for Global Land Remote Sensing Products(Grant No.OF202206).
文摘China boasts over 10,000 native useful vascular plants(NUVPs),spanning eight families and serving twelve dis-tinct uses.Given the importance of NUVPs,widely-confirmed in-situ conservation policies,such as establishing nature reserves,have been broadly implemented to protect them.However,the effectiveness of in-situ conser-vation efforts for NUVPs in China remains uncertain.Highlighting the importance of multi-family and multi-use plants,this research identified the spatial distribution pattern and diversity hotspots of NUVPs,evaluated the in-situ conservation effectiveness and provided the future conservation priority scheme.The results revealed that the spatial concentration of NUVPs is predominantly in the southwestern lowlands of China(<3,000 m),peaking around 109°E and 25°N.Importantly,diversity hotspots exhibited a significant spatial mismatch(over 80%)with the National Nature Reserve(NNR)network.Only about 17.7%and 13.3%of these hotspots are protected by NNR initiatives for endemic and nonendemic species,respectively.Additionally,the proposed Plants Conserva-tion Effectiveness Index(PCEI)proved more representative in addressing the two main crises faced by the studied species-species loss and human pressure,and found a decline in conservation effectiveness as the number of uses increased.Finally,future conservation priorities based on the PCEI highlight the Nanling Mountains,Heng-duan Mountains,Jiuwandashan,and Qilian Mountains as highly prioritized regions requiring focused efforts to address the impacts of climate change.Conversely,in sparsely distributed regions experiencing increasing human pressure,it is imperative to mitigate the expanding human footprint.
文摘In renewing tissues,mutations conferring selective advantage may result in clonal expansions1-4.In contrast to somatic tissues,mutations driving clonal expansions in spermatogonia(CES)are also transmitted to the next generation.This results in an effective increase of de novo mutation rate for CES drivers5-8.CES was originally discovered through extreme recurrence of de novo mutations causing Apert syndrome5.Here,we develop a systematic approach to discover CES drivers as hotspots of human de novo mutation.Our analysis of 54,715 trios ascertained for rare conditions9-13,6,065 control trios12,14-19 and population variation from 807,162 mostly healthy individuals20 identifies genes manifesting rates of de novo mutations inconsistent with plausible models of disease ascertainment.We propose 23 genes hypermutable at loss-of-function(LoF)sites as candidate CES drivers.An extra 17 genes feature hypermutable missense mutations at individual positions,suggesting CES acting through gain of function.CES increases the average mutation rate roughly 17-fold for LoF genes in both control trios and sperm and roughly 500-fold for pooled gain-of-function sites in sperm21.Positive selection in the male germline elevates the prevalence of genetic disorders and increases polymorphism levels,masking the effect of negative selection in human populations.
基金Supported by the Beijing Natural Sciences Foundation No.7242240Doctoral Startup Fund,No.2024BSZR052new teachers at the Beijing University of Chinese Medicine started the funding project,No.2022-JYB-XJSJJ-021.
文摘BACKGROUND Diabetic encephalopathy(DE)is a common and serious complication of diabetes that can cause death in many patients and significantly affects the lives of individuals and society.Multiple studies investigating the pathogenesis of DE have been reported.However,few studies have focused on scientometric analysis of DE.AIM To analyze literature on DE using scientometrics to provide a comprehensive picture of research directions and progress in this field.METHODS We reviewed studies on DE or cognitive impairment published between 2004 and 2023.The latter were used to identify the most frequent keywords in the keyword analysis and explore the hotspots and trends of DE.RESULTS Scientometric analysis revealed 1308 research papers on DE,a number that increased annually over the past 20 years,and that the primary topics explored were domain distribution,knowledge structure,evolution,and emergence of research topics related to DE.The inducing factors,comorbidities,pathogenesis,treatment,and animal models of DE help clarify its occurrence,development,and treatment.An increasing number of studies on DE may be a result of the recent increase in patients with diabetes,unhealthy lifestyles,and unhealthy eating habits,which have aggravated the incidence of this disease.CONCLUSION We identified the main inducing factors and comorbidities of DE,though other complex factors undoubtedly increase social and economic burdens.These findings provide vital references for future studies.
基金Supported by Scientific and Technological Innovation Project of China Academy of Chinese Medical Sciences,No.CI2023C015YLNational Natural Science Foundation of China,No.82174352.
文摘BACKGROUND The lack of specific symptoms of gastric cancer(GC)causes great challenges in its early diagnosis.Thus it is essential to identify the risk factors for early diagnosis and treatment of GC and to improve the survival rates.AIM To assist physicians in identifying changes in the output of publications and research hotspots related to risk factors for GC,constructing a list of key risk factors,and providing a reference for early identification of patients at high risk for GC.METHODS Research articles on risk factors for GC were searched in the Web of Science core collection,and relevant information was extracted after screening.The literature was analyzed using Microsoft Excel 2019,CiteSpace V,and VOSviewer 1.6.18.RESULTS A total of 2514 papers from 72 countries and 2507 research institutions were retrieved.China(n=1061),National Cancer Center(n=138),and Shoichiro Tsugane(n=36)were the most productive country,institution,or author,respectively.The research hotspots in the study of risk factors for GC are summarized in four areas,namely:Helicobacter pylori(H.pylori)infection,single nucleotide polymorphism,bio-diagnostic markers,and GC risk prediction models.CONCLUSION In this study,we found that H.pylori infection is the most significant risk factor for GC;single-nucleotide polymorphism(SNP)is the most dominant genetic factor for GC;bio-diagnostic markers are the most promising diagnostic modality for GC.GC risk prediction models are the latest current research hotspot.We conclude that the most important risk factors for the development of GC are H.pylori infection,SNP,smoking,diet,and alcohol.
基金Supported by the Science and Technology Project of Jiangsu Provincial Health Commission,No.ZDB2020003Nantong Science and Technology Program Project,No.MS22022035+1 种基金the Clinical Research Project of the Affiliated Hospital of Nantong University,No.LCYJB06Grant Fund for Research Hospitals in Jiangsu Province,No.YJXYY202204-YSB74.
文摘BACKGROUND Cognitive impairment,which manifests as a limited deterioration of specific functions associated with a particular disease,can lead to a general deterioration of the patient’s standard of living.Transcranial magnetic stimulation,a noninvasive neuromodulation technique,is frequently employed to treat cognitive impairment in neuropsychiatric disorders.AIM To analyzed the state of international research on neuromodulation methods for treating cognitive impairment between 2014 and 2023,with the aim of exploring the state of research worldwide and the most recent developments in this particular area.METHODS Articles and reviews pertaining to neuromodulation methods for cognitive impairment were examined using the web of science database between January 2014 and December 2023.Publications,nations,organizations,writers,journals,citations,and keywords data from the identified studies were systematically analyzed using the CiteSpace 6.3.R1 software.RESULTS A total of 2371 documents with 11750 authors and 9461 institutions,with some cooccurrences,were retrieved.The quantity of yearly publications is showing an increasing trend.The United States and China have emerged as important contributors.Among the institutes,Harvard University had the highest number of publications,while Rossi S an author who is frequently cited.Initially,the primary keywords included human motor cortex,placebo-controlled trials,and serotonin reuptake inhibitors.However,the emphasis gradually moved to substance use disorders,supplementary motor areas,neural mechanisms,and exercise.CONCLUSION The use of neuromodulation techniques to treat cognitive impairment has drawn interest from academics all around the world.This study revealed hotspots and new trends in the research of transcranial magnetic stimulation as a cognitive impairment rehabilitation treatment.These findings are hold significant potential to guide further research and thus promote transcranial magnetic stimulation as a treatment method for cognitive impairment.
基金National Natural Science Foundation of China,No.82273484Project of Chongqing Young and Middle-aged Medical Talents.
文摘BACKGROUND The transjugular intrahepatic portosystemic shunt(TIPS)is an important technique for treating complications related to portal hypertension in patients with cirrhosis,and the number of publications in the TIPS field continues to rise.AIM To facilitate an understanding of the research status and hotspots in the field of TIPS using CiteSpace bibliometric analysis.METHODS CiteSpace is a software that depicts the strength of relationships through graphics and connections with diverse functionalities and can be used to analyze the status and hotspots of areas of research.Articles on TIPS in the Web of Science Core Collection were retrieved,and CiteSpace software was used to visualize and analyze the number of publications,journals,countries,institutions,authors,keywords,and citations.RESULTS A total of 985 relevant documents were included in the analysis.From January 2013 to December 2022,the number of publications increased annually.The journal,institution,and author with the greatest number of publications in the field of TIPS are the Journal of Vascular and Interventional Radiology,the University of Bonn,and Jonel Trebicka,respectively.The main keywords used in this field are“transjugular intrahepatic portosystemic shunt”,“portal hypertension”,“cirrhosis”,“management”,“stent”,“hepatic encephalopathy”,“refractory ascite”,“survival”,“risk”,and“variceal bleeding”.The greatest obstacle to TIPS placement is currently the occurrence of hepatic encephalopathy.The research hotspots are the mechanism,risk factors,management,and control of hepatic encephalopathy.CONCLUSION This bibliometric analysis reported the research status and hotspots of TIPS.Research on postoperative hepatic encephalopathy is the research hotspot in this field.
基金supported by Natural Science Foundation Project of Guangdong Province(2020A1515010276)Guangzhou Science and Technology Project(2024A03J0207)Science and Technology Project of Quanzhou City(2022N030S).
文摘Purpose:To explore the status of current global research,trends and hotspots in the field of lupus retinopathy(LR).Methods:Publications related to LR from 2003 to 2022 were extracted from the Web of Science Core Collection(WOSCC).Citespace 6.2.R4 software was used to analyze the raw data.Bibliometric parameters such as publication quality,countries,authors,international cooperation,and keywords were taken into account.Results:A total of 315 publications were retrieved.The annual research output has increased significantly since 2010,especially since 2017.Marmor MF,Lee BR,and Melles RB contributed the highest number of articles published on LR.The top three publishing countries were the USA,China,and UK.Stanford University,Hanyang University,and Harvard Medical School were the top three producing institutions in the world for LR research.The top ten commonly used keywords include the following:systemic lupus erythematosus,retinopathy,retinal toxicity,antimalarial,hydroxychloroquine,optical coherence tomography,antiphospholipid syndrome,microvascular,optic neuritis,optical coherence tomography angiography.The keywords"optical coherence tomography angiography"and"vessel density"have exploded in recent years.Conclusion:By analyzing the current body of LR literature,specific global trends and hotspots for LR research were identified,presenting valuable information to track cutting-edge progress and for future cooperation between various authors and institutions.
文摘Pathophysiology is a science that deeply explores the occurrence and development of diseases,studies the mechanisms behind the final results,and integrates knowledge from multiple disciplines such as physiology,biochemistry,and immunology.The core lies in revealing the pathological and physiological changes during the disease process and analyzing the fundamental principles.In the medical education system,pathophysiology is an integral part of the foundational curriculum,serving as a bridge between basic medicine and clinical medicine.By studying pathophysiology,students can comprehensively understand the initial causes of diseases,pathological processes,and functional metabolic changes of the body under disease conditions.This discipline is also committed to cultivating students’systematic thinking,critical analysis skills,and problem-solving abilities,comprehensively enhancing their overall quality,making them more competitive and adaptable in the medical field.
基金Program for Guangdong Introducing Innovative and Entrepreneurial Teams,No.2019ZT08L213National Natural Science Foundation of China,No.41701631+1 种基金Guangdong Provincial Key Laboratory Project,No.2019B121203011Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),No.GML2019ZD0403。
文摘The Yangtze River Watershed in China is a climate change hotspot featuring strong spatial and temporal variability;hence, it poses a certain threat to social development. Identifying the characteristics of and regions vulnerable to climate change is significantly important for formulating adaptive countermeasures. However, with regard to the Yangtze River Watershed, there is currently a lack of research on these aspects from the perspective of natural and anthropogenic factors. To address this issue, in this study, based on the temperature and precipitation records from 717 meteorological stations, the RClim Dex and random forest models were used to assess the spatiotemporal characteristics of climate change and identify mainly the natural and anthropogenic factors influencing climate change hotspots in the Yangtze River Watershed for the period 1958-2017. The results indicated a significant increasing trend in temperature, a trend of wet and dry polarization in the annual precipitation, and that the number of temperature indices with significant variations was 2.8 times greater than that of precipitation indices. Significant differences were also noted in the responses of the climate change characteristics of the sub-basins to anthropogenic and natural factors;the delta plain of the Yangtze River estuary exhibited the most significant climate changes, where 88.89% of the extreme climate indices varied considerably. Furthermore, the characteristics that were similar among the identified hotpots, including human activities(higher Gross Domestic Product and construction land proportions) and natural factors(high altitudes and large proportions of grassland and water bodies), were positively correlated with the rapid climate warming.
基金This research was supported in part by National Natural Science Foundation of China，supported by Research Funds of China Space Medical Engineering，supported by State Key Laboratory of Space Medicine Fundamentals and Applications, China Astronaut Research and Training Centre
文摘The electrocardiogram （ECG） has broad applications in clinical diagnosis and prognosis of cardiovascular disease. Many researchers have contributed to its progressive development. To commemorate those pioneers, and to better study and promote the use of ECG, we reviewed and present here a systematic introduction about the history, hotspots, and trends of ECG. In the historical part, information including the invention, improvement, and extensive applications of ECG, such as in long QT syndrome （LQTS）, angina, and myocardial infarction （MI）, are chronologi- cally presented. New technologies and applications from the 1990s are also introduced. In the second part, we use the bibliometric analysis me- thod to analyze the hotspots in the field of ECG-related research. By using total citations and year-specific total citations as our main criteria, four key hotspots in ECG-related research were identified from 11 articles, including atrial fibrillation, LQTS, angina and MI, and heart rate variability. Recent studies in those four areas are also reported. In the final part, we discuss the future trends concerning ECG-related research. The authors believe that improvement of the ECG instrumentation, big data mining for ECG, and the accuracy of diagnosis and application will be areas of continuous concern.
基金the Joint Funds of the National Science Foundation of China and the Civil Aviation Administration(Nos.U1733105 and U1733203)the Sichuan Science and Technology Program(No.2019YFG0308)
文摘The hotspot recognition algorithm is proposed based on a potential collision in order to study the aircraft taxi conflicts in large airports.The spatial and temporal distribution characteristics of hotspots are analyzed based on the risk assessment model of hotspot constructed in this paper.Firstly,approaches for monitoring of the aerodrome movement were compared.The hotspot recognition algorithm taken into account of whether aircrafts'taxi track has spatial and temporal overlap based on the aerodrome surveillance radar(ASR)data was presented,by identifying the hotspots through analyzing whether the aircrafts'time of entering and exiting the same taxiway is overlap or not,and the heading difference and distance of the two aircrafts satisfy the specified threshold constraint condition.Then,the ASR data were divided into several parts,and then airport hotspots were recognized and the spatial and temporal distribution characteristics were analyzed.The risk assessment model of airport safety hotspots was constructed which is taken into account of the conflict probability and its severity consequence.Finally,based on the risk grade assessment criteria and hotspots'risk value,the risk grade ranking of hotspot in one airport of China was evaluated and designated.According to the result,the spatial and temporal distribution characteristics of airport hotspots were varied with the variation of airport traffic flow and operational mode of runway,which shows that the hotspots have the characteristics of dynamic periodicity and diurnal variation.And the risk assessment results were consistent with experts'opinions and actual operation condition,which verified the rationality of the hotspot recognition algorithm,risk assessment model as well as the risk grade ranking criteria.
基金The authors thank Dr.Jin-Ming Chen for his immense assistance.This study was supported by grants from the National Natural Science Foundation of China(No.31570220)Sino-Africa Joint Research Center(No.Y323771W07 and No.SAJC201322).
文摘Members of the aquatic plant genus Aponogeton are widely used commercially in aquariums because of their variable leaf shape and unique inflorescences.However,due to extensive similarity between species in this genus,morphological characters are generally inadequate for taxonomic classification.Currently,molecular makers available for taxonomic and phylogenetic studies of Aponogeton are limited.One approach to clarifying relationships between species in these complex groups is to use divergence hotspot regions within the genome.Here,we sequenced and analyzed the plastomes of five Aponogeton species collected from China,Zambia,and Kenya,and subsequently screened these plastomes for divergent DNA hotspots.The five plastomes are circular structures with sizes ranging from 154,167 bp to 154,860 bp.The Large and the Small Single Copies are separated by two Inverted Repeats.One hundred and thirteen unique genes were identified including 79 protein-coding,30 tRNA,and four rRNA genes.We found that the most abundant repeats in all but one species were mononucleotide repeats(A/T)and that there were 23 potential RNA ending sites.Interestingly,a^3 kb inversion,which includes the accD gene,was detected within the Asian species of Aponogeton.The inversion may be related to more frequent exchanges between this region and the nuclear genome.Furthermore,we detected mutational hotspot sites among the five Aponogeton species.Three of these hotspots are intergenic spacer regions(accD-psaI,rbcL-accD and trnH-GUG-psbA)that might be suitable for use as barcodes to resolve intra-generic relationships.We also identified four highly variable protein-coding genes(ccsA,rpl22,rps16 and ycf1)may be used as barcodes to resolve the higher-level phylogenies.Our study will provide valuable molecular resources for the taxonomic and phylogenomic study of the complex genus Aponogeton.
基金supported by a scientific research project of Shanxi Provincial Health Department,China(No.201201031)
文摘Objective: To analyze clinical psychological nursing research hotspots in China and variation trends in order to provide reference points on the current state of development of clinical psychological nursing and future research hotspots.Method: Clinical psychological nursing research literature sourced from Wanfang Data for the three periods of 2007-2009, 2010-2012, and 2013-2015 were selected as the research sample. A bibliographic co-occurrence analysis system(BICOMB software) was used to perform keyword word frequency analysis and generate a keyword co-occurrence matrix. In addition, Ucinet software's Netdraw tool was used to create visualized network diagrams.Results: A total of 27890 articles were retrieved, and word frequency analysis revealed that the highestfrequency keywords consisted of anxiety, depression, the elderly, expectant women, coronary heart disease, diabetes, breast cancer, perioperative period, quality of life, and psychological intervention.Research hotspot analysis revealed that consistent hotspots comprised anxiety, depression, health education, and perioperative period; expectant women became a hotspot during 2010-2012, and quality of life and efficacy became hotspots during 2013-2015.Conclusions: In addition to the care process, clinical psychological nursing research hotspots in China have increasingly included the effectiveness of psychological nursing and impact on patient quality of life. In addition, research hotspots have been influenced by the incidence of illnesses and people's health consciousness.
基金The National Natural Science Foundation of China under contract No.41406146the Open Fund from Laboratory for Marine Fisheries Science and Food Production Processes at Qingdao National Laboratory for Marine Science and Technology of China under contract No.2017-1A02Shanghai Universities First-class Disciplines Project-Fisheries(A)
文摘We examined the scale impacts on spatial hot and cold spots of CPUE for Ommastrephes bartramii in the northwest Pacific Ocean. The original fishery data were tessellated to 18 spatial scales from 5′×5′ to 90′×90′ with a scale interval of 5′ to identify the local clusters. The changes in location, boundaries, and statistics regarding the Getis-Ord Gi＊ hot and cold spots in response to the spatial scales were analyzed in detail. Several statistics including Min, mean, Max, SD, CV, skewness, kurtosis, first quartile（Q1）, median, third quartile（Q3）, area and centroid were calculated for spatial hot and cold spots. Scaling impacts were examined for the selected statistics using linear, logarithmic, exponential, power law and polynomial functions. Clear scaling relations were identified for Max, SD and kurtosis for both hot and cold spots. For the remaining statistics, either a difference of scale impacts was found between the two clusters, or no clear scaling relation was identified. Spatial scales coarser than 30′ are not recommended to identify the local spatial patterns of fisheries because the boundary and locations of hot and cold spots at a coarser scale are significantly different from those at the original scale.
文摘The soils, tropical climate, and network of canals and rivers of southern Vietnam have created one of the most diverse tropical jungles and intensely cultivated landscapes of Southeast Asia. This paradise has a long history of numerous wars, foreign occupations, and most recently the Second Indochina War (aka the Vietnam War 1965-1972) which defoliated rain forests and ancient wetland mangroves and left behind contaminated soil and sediment hotspots. During this war, the United States (US) military sprayed 80 million liters of Agent Orange contaminated with the dioxin TCDD in a guerrilla war against communist insurgents. Agent Orange was a synthetic plant growth regulator comprised of equal amounts of two herbicides 2,4-dichloro phenoxyacetic acid C8H6Cl2O3 (2,4-D) and 2,4,5-trichlorophenoxyacetic acid C8H5Cl3O3 (2,4,5-T). TCDD, the dioxin, 2,3,7,8-tetrachlorodibenzodioxin (C12H4Cl4O2) was an unintended byproduct of the accelerated combustion process used in the manufacture of herbicides containing 2,4,5-T. Agent Orange has frequently been blamed for soil and sediment contamination and long-term human health problems;however, the true source of harm is the dioxin TCDD. Agent Orange has a short half-life of days and weeks after application to vegetation, and has not been found to persist, after 50 years, in the water or soils of southern Vietnam. However, the half-life of dioxin TCDD depends on where it is deposited and varies from 1 to 3 years on soil surfaces that have been fully exposed to sunlight, to as long as 20 to 50 years or more when buried in tropical subsoils, and more than 100 years in river and sea sediments. Dioxin TCDD was heavily concentrated in the US Air Force bases in Vietnam where the herbicides were stored, loaded on planes and helicopters for aerial spraying, and used extensively around military base perimeter fences as a security measure to prevent surprise attacks. Bien Hoa Air Force base, 40 km northeast of Ho Chi Minh City, continues to be one of the mega-hotspots where after 48 years the dioxin TCDD levels in fish and shrimp are still high and fishing is banned in ponds and lakes adjacent to the airbase. Although expensive, one of the most effective remediation to dioxin TCDD contaminated soils is incineration which is the recommended method of dioxin TCDD disposal.
