Top 100 most-cited articles on exosomes in the field of cancer: a bibliometric analysis and evidence mapping

Top 100 cited research on COVID-19 vaccines: A bibliometric analysis and evidence mapping

The outbreak of the COVID-19 has seriously affected the whole society, and vaccines were the most effective means to contain the epidemic. This paper aims to determine the top 100 articles cited most frequently in COVID-19 vaccines and to analyze the research status and hot spots in this field through bibliometrics, to provide a reference for future research. We conducted a comprehensive search of the Web of Science Core Collection database on November 29, 2023, and identified the top 100 articles by ranking them from highest to lowest citation frequency. In addition, we analyzed the year of publication, citation, author, country, institution, journal, and keywords with Microsoft Excel 2019 and VOSviewer 1.6.18. Research focused on vaccine immunogenicity and safety, vaccine hesitancy, and vaccination intention.

Hotspots and frontiers of autophagy and chemotherapy in lung cancer: a bibliometric and visualization analysis from 2003 to 2023

Autophagy was considered to induce resistance in chemotherapy, which was significantly associated with proliferation of cancer; however, few bibliometric studies on the relation between autophagy and chemotherapy in lung cancer are available. The aim of the present study was to provide a comprehensive overview of the knowledge structure and research hotspots of autophagy and chemotherapy in lung cancer by bibliometric analysis. Publications related to autophagy and chemotherapy in lung cancer from 2003 to 2023 were searched on the Web of Science Core Collection (WoSCC) database. The bibliometric analysis was conducted by using VOSviewers, CiteSpace, and the R package "bibliometrix." A total of 675 articles from 70 countries, led by China and the United States, were included in the analysis. The number of publications related to autophagy and chemotherapy in lung cancer is increasing year by year. Nanjing Medical University, Zhejiang University, China Medical University, and Sichuan University are among the main research institutions contributing to this field. The journal Cancers is the most popular publication in this area, with Autophagy being the most co-cited journal. These publications involve 4481 authors, with Chiu Chien-chih and Gewirtz David having published the most papers, and Noboru Mizushima being the most frequently co-cited author. Studying the relation between autophagy and chemotherapy in the occurrence and development of lung cancer, and exploring therapeutic strategies involving autophagy and chemotherapy in lung cancer, are the primary topics in this research field. "Tumor stem cells," "microRNA," and "EGFR" emerge as the primary keywords in the emerging research hotspots. Indeed, this bibliometric study provides valuable insights into the research trends and developments concerning autophagy and chemotherapy in lung cancer. By identifying recent research frontiers and highlighting hot directions, this study serves as a valuable reference for scholars interested in understanding the relationship between autophagy and chemotherapy in lung cancer. The comprehensive summary of findings offers a foundation for further exploration and advancement in this critical area of cancer research.

Knowledge domains and emerging trends in radiotherapy in oesophageal cancer from 2004 to 2023: a bibliometric analysis and visualization study

Esophageal cancer (EC) is a malignant tumour with high morbidity and mortality rates. Recent studies have shown that much progress has been made in the research of radiotherapy in EC. This study aims to provide a comprehensive overview of the knowledge structure and research hotspots of radiotherapy in EC through bibliometrics. Publications related to radiotherapy in EC from 2014 to 2023 were searched on the web of science core collection database. VOSviewers, CiteSpace and R package 'bibliometrix' were used to conduct this bibliometric analysis. In total, 4258 articles from 76 countries led by China and the USA were included. The Chinese Academy of Medical Sciences-Peking Union Medical College has the highest number of publications. International Journal of Radiation Oncology Biology Physics is the most popular journal and also the most co-cited journal in this field. These publications come from 21 972 authors among which Liao Zhongxing had published the most papers and Cooper JS was co-cited most often. Neoadjuvant chemoradiotherapy and strategies based on it are the main topics in this research field. 'IMRT' and 'immunotherapy' are the primary keywords of emerging research hotspots. This is a bibliometric study that comprehensively summarizes the research trends and developments of radiotherapy in EC. This information identifies recent research frontiers and hot directions, which will provide a reference for scholars studying radiotherapy in EC.

Visualizing the landscape of appendiceal tumor research after 2010: A bibliometric study

BACKGROUND

Despite the rarity of appendiceal tumors, research in this field has intensified, resulting in a growing number of studies and published papers. Surprisingly, no comprehensive bibliometric analysis has specifically addressed appendiceal tumors.

AIM

To offer a thorough analysis of the current landscape and future trends in appendiceal tumor research.

METHODS

In our bibliometric analysis studies, we explored the Web of Science Core Collection database. The bibliographic details of the chosen publications were automatically converted and analyzed using the bibliometric package in the R environment. Additionally, we employed VoSviewer to create cooperation network maps for countries, institutions, and authors, as well as clustering maps for keywords. Furthermore, CiteSpace, another software tool, was utilized to build dual-map overlays of journals and analyze references with citation bursts.

RESULTS

Our study included 780 English-language articles published after 2010. The number of related publications and citations has increased in the past decade. The United States leads in this area, but there is a need to improve cooperation and communication among countries and institutions. Co-occurrence analysis also revealed close collaboration among different authors. Annals of Surgical Oncology was the most influential journal in this field. Analysis of references with high co-citations and references with citation bursts, consistent with analysis of keywords and hotspots, indicated that current research primarily centers on the classification and management of appendiceal mucinous neoplasms and consequent pseudomyxoma peritonei. Despite the abundance of clinical studies, a greater number of in-depth basic research studies should be conducted.

CONCLUSION

Current research on appendiceal tumors focuses on classification and management of appendiceal mucinous neoplasms and pseudomyxoma peritonei. Enhanced collaboration and basic research are vital for further advancement.

Immune control in Kawasaki disease knowledge mapping: a bibliometric analysis

BACKGROUND

Kawasaki disease is a systemic vascular disease with an unclear pathophysiology that primarily affects children under the age of five. Research on immune control in Kawasaki disease has been gaining attention. This study aims to apply a bibliometric analysis to examine the present and future directions of immune control in Kawasaki disease.

METHODS

By utilizing the themes "Kawasaki disease," "Kawasaki syndrome," and "immune control," the Web of Science Core Collection database was searched for publications on immune control in Kawasaki disease. This bibliometric analysis was carried out using VOSviewers, CiteSpace, and the R package "bibliometrix."

RESULTS

In total, 294 studies on immune control in Kawasaki disease were published in Web of Science Core Collection. The three most significant institutions were Chang Gung University, the University of California San Diego, and Kaohsiung Chang Gung Memorial Hospital. China, the United States, and Japan were the three most important countries. In this research field, Clinical and Experimental Immunology was the top-referred journal, while the New England Journal of Medicine was the most co-cited journal. The Web of Science Core Collection document by McCrindle BW et al. published in 2017 was the most cited reference. Additionally, the author keywords concentrated on "COVID-19," "SARS-CoV-2," and "multisystem inflammatory syndrome in children" in recent years.

CONCLUSION

The research trends and advancements in immune control in Kawasaki disease are thoroughly summarised in this bibliometric analysis, which is the first to do so. The data indicate recent research frontiers and hot directions, making it easier for researchers to study the immune control of Kawasaki disease.

Top 100 Most Cited Papers on Multimodality Imaging for Complex Congenital Heart Disease. A Bibliometric Analysis

Complex congenital heart disease (CCHD) is a group of heart defects present at birth. Some imaging methods can support the diagnosis of these pathologies, such as echocardiography, computed tomography, and magnetic resonance imaging. This study aimed to perform a bibliometric analysis of the top 100 articles cited on CCHD. Articles from 2013 to 2023 found in Scopus were scanned using 15 CCHD topics titles crossed with echocardiography, computed tomography, and magnetic resonance imaging. Duplicated manuscripts were eliminated using Microsoft Excel software, and the publications were ranked according to their citation count. This study selected and analyzed the top 100 most cited English-language papers. The top 100 most cited publications accumulated 16,563 citations. The manuscript with the most citations obtained 1086, representing 6.55% of the total citations. The year 2014 had the highest number of publications, with 27 papers. The first authors had affiliations from 44 countries; the United States was the country that contributed the most, with 54 manuscripts. Boston Children's Hospital was the institution that provided more articles to the top 100. Finally, the Ebstein anomaly was the topic with the highest number of citations. This study identified the 100 most cited on CCHD, and the results obtained can provide practical guidance to clinicians and researchers to familiarize themselves with the most influential publications in this field.

Knowledge mapping of programmed cell death in osteonecrosis of femoral head: a bibliometric analysis (2000-2022)

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a common, refractory and disabling disease of orthopedic department, which is one of the common causes of hip pain and dysfunction. Recent studies have shown that much progress has been made in the research of programmed cell death (PCD) in ONFH. However, there is no bibliometric analysis in this research field. This study aims to provide a comprehensive overview of the knowledge structure and research hot spots of PCD in ONFH through bibliometrics.

METHOD

The literature search related to ONFH and PCD was conducted on the Web of Science Core Collection (WoSCC) database from 2002 to 2021. The VOSviewers, "bibliometrix" R package and CiteSpace were used to conduct this bibliometric analysis.

RESULTS

In total, 346 articles from 27 countries led by China and USA and Japan were included. The number of publications related to PCD in ONFH is increasing year by year. Shanghai Jiao Tong University, Xi An Jiao Tong University, Wuhan University and Huazhong University of Science and Technology are the main research institutions. Molecular Medicine Reports is the most popular journal in the field of PCD in ONFH, and Clinical Orthopaedics and Related Research is the most cocited journal. These publications come from 1882 authors among which Peng Hao, Sun Wei, Zhang Chang-Qing, Zhang Jian and Wang Kun-zheng had published the most papers and Ronald S Weinstein was cocited most often. Apoptosis, osteonecrosis, osteonecrosis of the femoral head, glucocorticoid and femoral head appeared are the main topics the field of PCD in ONFH. Autophagy was most likely to be the current research hot spot for PCD in ONFH.

CONCLUSION

This is the first bibliometric study that comprehensively summarizes the research trends and developments of PCD in ONFH. This information identified recent research frontiers and hot directions, which will provide a reference for scholars studying PCD in ONFH.

A Bibliometric Analysis of Exosomes Therapy in the Treatment of Osteoarthritis from 2012 to 2022

Purpose

Osteoarthritis (OA) is a common clinical disease characterized by the destruction of articular cartilage, subchondral ossification, cystic degeneration and osteophyte formation. Recently, more and more scholars draw attention to exosomes in the field of OA, and exciting breakthroughs have been achieved in recent years. However, bibliometric analysis of the literature in this research field is lacking. Considering its potential in treatment of OA, this article aimed to analyze the research status and identify future hotspots of exosomes in osteoarthritis in recent 10 years by bibliometrics tools.

Methods

Relevant publications in this field from 2012 to 2022 was retrieved from the Web of Science core collection database (WOSSCC). And we used Vosviewers, CiteSpace, an online analysis platform and the R package "Bibliometrix" for bibliometric analysis.

Results

A total of 484 publications (including 319 articles and 165 reviews) from 51 countries, 720 institutions, were included in this study. IRCCS Ist Ortoped Galeazzi, Shanghai Jiao Tong University, and Sun Yat-sen University are the leading research institutions in this field. International Journal of Molecular Sciences contributed the largest number of articles, and Osteoarthritis and Cartilage is the most co-cited journal. Of the 2664 scholars who participated in the study, Ragni E, De Girolamo L, Orfei CP, and Colombini A had the largest number of articles. Zhang, SP is the most co-cited author. "Mesenchymal stem cell", "biomaterials", "Inflammation" and "regenerative medicine" are the keywords in the research.

Conclusion

This is the first bibliometric analysis of exosomes in osteoarthritis. We explored current research status in recent years and identified frontiers and hot spots in this research field. We highlight the significant roles of mesenchymal stem cell-derived exosomes (MSC-Exos) in the treatment of osteoarthritis, and identified exosomal biomaterials as frontier in this research domain, which can provide reference for the researchers who focus on this research field.

Global hotspots and emerging trends in 3D bioprinting research

Three-dimensional (3D) bioprinting is an advanced tissue engineering technique that has received a lot of interest in the past years. We aimed to highlight the characteristics of articles on 3D bioprinting, especially in terms of research hotspots and focus. Publications related to 3D bioprinting from 2007 to 2022 were acquired from the Web of Science Core Collection database. We have used VOSviewer, CiteSpace, and R-bibliometrix to perform various analyses on 3,327 published articles. The number of annual publications is increasing globally, a trend expected to continue. The United States and China were the most productive countries with the closest cooperation and the most research and development investment funds in this field. Harvard Medical School and Tsinghua University are the top-ranked institutions in the United States and China, respectively. Dr. Anthony Atala and Dr. Ali Khademhosseini, the most productive researchers in 3D bioprinting, may provide cooperation opportunities for interested researchers. Tissue Engineering Part A contributed the largest publication number, while Frontiers in Bioengineering and Biotechnology was the most attractive journal with the most potential. As for the keywords in 3D bioprinting, Bio-ink, Hydrogels (especially GelMA and Gelatin), Scaffold (especially decellularized extracellular matrix), extrusion-based bioprinting, tissue engineering, and in vitro models (organoids particularly) are research hotspots analyzed in the current study. Specifically, the research topics "new bio-ink investigation," "modification of extrusion-based bioprinting for cell viability and vascularization," "application of 3D bioprinting in organoids and in vitro model" and "research in personalized and regenerative medicine" were predicted to be hotspots for future research.

Research progress and future directions on intraductal papillary mucinous neoplasm: A bibliometric and visualized analysis of over 30 years of research

BACKGROUND

Malignant change from low-grade dysplasia to high-grade dysplasia and invasive carcinoma following an adenoma-carcinoma sequence is becoming more common in intraductal papillary mucinous neoplasm (IPMN) of the pancreas. The aim of this study is to analyze their main characteristics and recent research trends in IPMNs and consequently create better understandings of the current situation and trends.

METHODS

A comprehensive search was performed in The Science Citation Index Expanded of the Web of Science. All articles between 1990 and 2021 were searched. VOS viewer (Leiden University, Leiden, Netherlands) was used for a qualitative and quantitative analysis of keywords, constituting maps based on co-occurrence matrix.

RESULTS

A total of 1658 eligible articles were screened among the 3950 identified articles for this subject. Finally, 879 articles were included in this study. Many articles on IPMN have been published in Japan and South Korea. Tanaka published the highest number of articles (n = 26, citations = 11,143). The Pancreas published the highest number of articles. (n = 100, citations = 2533). These articles were grouped into 4 clusters including basic research, disease overview, management/prognosis and malignant IPMN by using bibliometric keywords network analysis. Overlay visualization demonstrates, a trend of the studies has been changed from basic research or disease to management or prognosis.

CONCLUSIONS

In this study, we found and highlight the most cited and influential articles related to IPMN. Plus, this study analyzed global research trends in IPMN over the past 30 years and provides insight into the features and research hotspots of the articles in IPMN research.

Knowledge Mapping of Exosomes in Autoimmune Diseases: A Bibliometric Analysis (2002–2021)

Background

Autoimmune diseases (AIDs) are a class of chronic disabling diseases characterized by inflammation and damage to muscles, joints, bones, and internal organs. Recent studies have shown that much progress has been made in the research of exosomes in AIDs. However, there is no bibliometric analysis in this research field. This study aims to provide a comprehensive overview of the knowledge structure and research hotspots of exosomes in AIDs through bibliometrics.

Method

Publications related to exosomes in AIDs from 2002 to 2021 were searched on the web of science core collection (WoSCC) database. VOSviewers, CiteSpace and R package “bibliometrix” were used to conduct this bibliometric analysis.

Results

312 articles from 48 countries led by China and the United States were included. The number of publications related to exosomes in AIDs is increasing year by year. Central South University, Sun Yat Sen University, Tianjin Medical University and University of Pennsylvania are the main research institutions. Frontiers in immunology is the most popular journal in this field, and Journal of Immunology is the most co-cited journal. These publications come from 473 authors among which Ilias Alevizos, Qianjin Lu, Wei Wei, Jim Xiang and Ming Zhao had published the most papers and Clotilde Théry was co-cited most often. Studying the mechanism of endogenous exosomes in the occurrence and development of AIDs and the therapeutic strategy of exogenous exosomes in AIDs are the main topics in this research field. “Mesenchymal stem cells”, “microRNA”, “biomarkers”, “immunomodulation”, and “therapy” are the primary keywords of emerging research hotspots.

Conclusion

This is the first bibliometric study that comprehensively summarizes the research trends and developments of exosomes in AIDs. This information identifies recent research frontiers and hot directions, which will provide a reference for scholars studying exosomes.

Global Research Mapping of Psycho-Oncology Between 1980 and 2021: A Bibliometric Analysis

Background and Aim

Psycho-oncology is a cross-disciplinary and collaborative sub-specialty of oncology that focuses on the psychological, behavioral, ethical, and social aspects of cancer in clinical settings. The aim of this bibliometric study was to analyze and characterize the research productivity and trends in psycho-oncology between 1980 and 2021.

Methodology

In May 2022, the Scopus^® database was searched for psycho-oncology-related publications using predetermined search keywords with specific restrictions. Lotka’s law was applied to check the authors’ productivity, while Bradford’s law was used to assess the core journals in this field. The data was analyzed for different bibliometric indicators in the Biblioshiny package, an RStudio tool for bibliometric analysis.

Results

The initial search resulted in a total of 2,906 publications. Of which, 1,832 publications were included in the final analysis, published between 1980 and 2021. The analyzed publications were written by 7,363 authors from 74 countries and published in 490 journals. There has been a significant increase in psycho-oncology-related publications after 2010. The most productive year was 2021 (n = 365). The annual scientific growth rate was found to be 13.9%. The most relevant leading author in terms of publications was Luigi Grassi from the University of Ferrara, Italy (n = 42). Lotka’s law found that the number of authors declined as the number of papers written increased. The core journals were Psycho-Oncology, Supportive Care in Cancer, and Journal of Psychosocial Oncology. The most frequently used author’s keywords other than searching keywords were cancer, oncology, quality of life, depression, and anxiety. Recent psycho-oncology-related topics included mental health, COVID-19 infection in humans, people, pandemic, and tumor. The University of Sydney was the top-ranked institution. The leading country in terms of publications, citations, corresponding author country, and international collaboration was the United States of America (United States). The United States had the strongest collaboration with Australia and Canada.

Conclusion

The research hotspots include mental health conditions and interventions in cancer patients. We identified international collaboration and research expenditure to be strongly associated with psycho-oncology research productivity. Researchers’ collaboration, which is visible among developed countries, should be extended to low-income countries in order to expand psycho-oncology-related research and understanding.

An Overview of Current Research on Mesenchymal Stem Cell-Derived Extracellular Vesicles: A Bibliometric Analysis From 2009 to 2021

Background: Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are important mediators of intercellular communication and participate in numerous physiological and pathological processes in the body. This study aims to introduce the research status, analyze the research hotspots, and predict the development trend through bibliometric analysis of MSC-EVs.

Methods: We searched all relevant literature on MSC-EVs from 2009 to 2021 in the Web of Science. R-bibliometrix, VOSviewer, and CiteSpace software were used to visualize the quantitative analysis of the published literature, including co-authorship, co-occurrence, citation, and co-citation, to provide objective presentation and predictions in the field.

Results: A total of 1595 articles and reviews on MSC-EVs published between 2009 and 2021 were identified. The annual publication outputs increased at an exponential rate, reaching as high as 555 publications in 2021. China contributed the most publications (n = 899, 56.36%) and had the most citations (n = 24,210). The United States had the strongest intensity of cooperation in this field. Shanghai Jiao Tong University had the maximum number of publications (n = 79). In terms of the number of publications and co-citations, the journal of Stem cell research & therapy ranked first. Camussi G was the most productive and most cited author. The top three themes in the research area were cell biology, research experimental medicine, and biochemistry molecular biology. Keyword co-occurrence and co-citation clustering analysis revealed that studies of MSC-EVs covered cellular origin (bone marrow mesenchymal stem cell, adipose-derived mesenchymal stem cell), injurious diseases (spinal cord injury, acute lung injury, ischemia/reperfusion injury, acute kidney injury, traumatic brain injury), tumor (breast cancer, tumor microenvironment), biological processes (drug delivery system, angiogenesis, inflammation, proliferation, differentiation, senescence), and molecular mechanisms (signaling pathway, signal transduction, oxidative stress, VEGF, TGF β).

Conclusions: Studies on MSC-EVs have shown a steep growth trend in recent years. Available studies mostly focused on the therapeutic effects and underlying mechanisms of MSC-EVs in aplastic diseases. Multidisciplinary integration is a development trend in this field, and senescence-related topics might be the focus of future research on MSC-EVs.

Bibliometric Analysis and Visualization Mapping of Anthrax Vaccine Publications from 1991 through 2021

Purpose: This study aims to analyze and characterize anthrax vaccine-related research, key developments, global research trends, and mapping of published scientific research articles during the last three decades (1991–2021). Methods: A bibliometric and visualized study was conducted. The Web of Science Core Collection database (WoSCC) was searched using relevant keywords (“Anthrax” OR “Anthrax bacterium” OR “Bacillus anthracis” OR “Bacteridium anthracis” OR “Bacillus cereus var. Anthracis” (Topic)) AND (“Vaccine” OR “Vaccines” OR “Immunization” OR “Immunisation” OR “Immunizations” OR “Immunisations” (Topic)) with specific restrictions. The data was analyzed and plotted by using different bibliometric software and tools (HistCiteTM software, version 12.3.17, Bibliometrix: An R-tool version 3.2.1, and VOSviewer software, version 1.6.17). Results: The initial search yielded 1750 documents. After screening the titles and abstracts of the published studies, a total of 1090 articles published from 1991 to 2021 were included in the final analysis. These articles were published in 334 journals and were authored by 4567 authors from 64 countries with a collaboration index of 4.32. The annual scientific production growth rate was found to be 9.68%. The analyzed articles were cited 31335 times. The most productive year was 2006 (n = 77, 7.06%), while the most cited year was 2007 (2561 citations). The leading authors and journals in anthrax research were Rakesh Bhatnagar from Jawaharlal Nehru University, India (n = 35, 3.21%), and Vaccine (n = 1830, 16.51%), while the most cited author and journal were Arthur M. Friedlander from the United States Department of Defense (n = 2762), and Vaccine (n = 5696), respectively. The most studied recent research trend topics were lethal, double-blind, epidemiology, B surface antigen, disease, and toxin. The United States of America (USA) was the most dominant country in terms of publications, citations, corresponding author country, and global collaboration in anthrax vaccine research. The USA had the strongest collaboration with the United Kingdom (UK), China, Canada, Germany, and France. Conclusion: This is the first bibliometric study that provides a comprehensive historical overview of scientific studies. From 2006 to 2008, more than 20% of the total articles were published; however, a decrease was observed since 2013 in anthrax vaccine research. The developed countries made significant contributions to anthrax vaccine-related research, especially the USA. Among the top 10 leading authors, six authors are from the USA. The majority of the top leading institutions are also from the USA. About 90% of the total studies were funded by the United States Department of Health and Human Services (HHS), National Institutes of Health (NIH), USA, and the National Institute of Allergy and Infectious Diseases (NIAID), USA.

Advances in Breast Cancer Management and Extracellular Vesicle Research, a Bibliometric Analysis

Extracellular vesicles transport variable content and have crucial functions in cell–cell communication. The role of extracellular vesicles in cancer is a current hot topic, and no bibliometric study has ever analyzed research production regarding their role in breast cancer and indicated the trends in the field. In this way, we aimed to investigate the trends in breast cancer management involved with extracellular vesicle research. Articles were retrieved from Scopus, including all the documents published concerning breast cancer and extracellular vesicles. We analyzed authors, journals, citations, affiliations, and keywords, besides other bibliometric analyses, using R Studio version 3.6.2. and VOSviewer version 1.6.0. A total of 1151 articles were retrieved, and as the main result, our analysis revealed trending topics on biomarkers of liquid biopsy, drug delivery, chemotherapy, autophagy, and microRNA. Additionally, research related to extracellular vesicles in breast cancer has been focused on diagnosis, treatment, and mechanisms of action of breast tumor-derived vesicles. Future studies are expected to explore the role of extracellular vesicles on autophagy and microRNA, besides investigating the application of extracellular vesicles from liquid biopsies for biomarkers and drug delivery, enabling the development and validation of therapeutic strategies for specific cancers.

Characterization of top 100 researches on e-waste based on bibliometric analysis

With rapid development of energy, information, and communication technology, e-waste problem has become one of the global issues to be settled urgently. The main features on publication years, journals, countries and institutions, authors, keywords, and content types of the 100 most-cited articles on e-waste had been unfolded in this research. The direction and way forward were illustrated, the trends to date were demonstrated, and the terrain and pathways were evaluated on the research of e-waste. Bibliometric analysis method was applied to analyze various attributes on the 100 most-cited articles which were retrieved from WoSCC on May 25, 2021, by utilizing the software tools Microsoft Excel 2016 and VOS viewer 1.6.9. The publication year and citation number of the 100 articles ranged between 2003 and 2017 and from 83 to 925, respectively. Environmental Science & Technology (n=17) published the maximum articles. Waste Management, Journal of Hazardous Materials, and Environmental Science & Technology were the core journals on e-waste. One hundred twenty-three institutions and 25 countries were involved in publishing the 100 articles. Three hundred seventy authors contributed to the 100 articles in total. A total of 267 keywords occurred in the 100 articles. The keywords "e-waste" and "recycling" held the highest occurrences. The study content of the 100 articles could be classified into four types including the characteristic-and-property type, the environment-and-health type, the management-and-economic type, and the technique-and-processing type. Overall completeness and applicability of the evidence found in this study were verified sufficiently; the potential biases in the review process were also considered. The innovations of the research from the past bibliometric analysis work on e-waste were stated, and the implication for practice and research of this study were explained as well. 2007, 2008, and 2009 were a peak of the researches on e-waste, while the recent years were experiencing a valley. China and its institutions were most influential in this field on e-waste. India was becoming more and more influential on e-waste research in the world. Nigeria was the research center in Africa, and Brazil was the research center in Latin America. Wong Minghung was the most important expert on e-waste. The impact on environment and human being's health was the hot topic of researches on e-waste; the characteristic and property of e-waste were studied not enough. The researches of technique and processing would be the direction and way forward in the study field on e-waste. The characteristic and property on e-waste would need more attention to be researched. The researchers could develop new pathways based on and beyond the four types of content evaluated in this research.

Progress and challenges of network meta-analysis

In the past years, network meta-analysis (NMA) has been widely used among clinicians, guideline makers, and health technology assessment agencies and has played an important role in clinical decision-making and guideline development. To inform further development of NMAs, we conducted a bibliometric analysis to assess the current status of published NMA methodological studies, summarized the methodological progress of seven types of NMAs, and discussed the current challenges of NMAs.

COVID-19 vaccine research focusses on safety, efficacy, immunoinformatics, and vaccine production and delivery: a bibliometric analysis based on VOSviewer

Coronavirus Disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has affected tens of millions of people globally since it was declared a pandemic by the World Health Organization (WHO) on March 11, 2020. There is an urgent need for safe and effective preventive vaccines to curb this pandemic. A growing amount of related research has been published. This study aimed to provide the current status of COVID-19 vaccine using bibliometric analysis. We searched Embase.com and MEDLINE comprehensively and included articles, articles in press, reviews, short surveys, conference abstracts and conference papers about COVID-19 vaccine. VOSviewer1.6.11 (Leiden University, Leiden, Netherlands) was applied to perform the bibliometric analysis of these papers. A total of 1,312 papers were finally included. The BMJ has been the most popular journal in this field. The United States maintained a top position worldwide and has provided a pivotal influence, followed by China, India and United Kingdom. Among all the institutions, Harvard University was regarded as a leader for research collaboration. We analyzed the keywords and identified seven COVID-19 vaccine research hotspot clusters. COVID-19 vaccine research hotspots focus on clinical trials on vaccine safety and efficacy, research on vaccine immunology and immunoinformatics, and vaccine hesitancy. Our analysis results demonstrated that cooperation between countries, institutions, and authors were insufficient. The results suggested that clinical trials on vaccine safety, efficacy, immunology, immunoinformatics, production and delivery are research hotspots. Furthermore, we can predict that there will be a lot of research focusing on vaccine adverse reactions.