87 results on '"Yunling Xu"'
Search Results
2. Immune Effects of Macrophages in Rheumatoid Arthritis: A Bibliometric Analysis From 2000 to 2021
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YunLing Xu, Zhongmin Zhang, Jiaolong He, and Zhenxing Chen
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rheumatoid arthritis ,macrophages ,bibliometrics ,hotspots ,research status ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease characterized by macrophage activation. The current characteristics, hotspots, and research frontiers of macrophage-related RA were analyzed using bibliometric analysis. Relatedpapers published from 2000 to 2021 in the Web of Science database were retrieved. The diagrams were generated and analyzed using the bibliometric software package. VOSviewer and CiteSpace were used to evaluate and visualize the research trends and hotspots in macrophage-related RA. A total of 7253 original articles were obtained. Global research on macrophage-related RA is in an advanced stage of development, with core authors, teams and research institutions emerging. United States has published the most papers, received the most citations, and had the highest H-index over the last 22 years. The University of Amsterdam and the journal of Arthritis and Rheumatism are the most productive research institutions and journals. Tak PP’s (St Vincent’s Hospital) paper has the highest publication and citation scores. The keywords “bone loss” and “polarization” have the highest frequency. Additionally, the study of macrophage polarization in RA has been research focus in recent years. This study demonstrates that research on macrophages in RA will continue. China is a significant producer, whereas the United States is an influential nation in this regard. In the last decade, most studies have concentrated on fundamental research. Recent studies have shown how macrophages play a role in controlling and weakening inflammation, and drug delivery and mechanism have come to the fore.
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- 2022
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3. Research and application of herbal medicine in the treatment of chronic kidney disease since the 21st century: A visualized bibliometric analysis
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Yunling Xu, Jia Chen, He Wang, and Ying Lu
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herbal medicine ,chronic kidney disease ,bibliometrics ,hotspots ,research status ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Background: Here, a bibliometric and knowledge-map analysis was used to analyze the research status and application of herbal medicine for the treatment of chronic kidney disease (CKD). By looking for research hotspots and key topics, we provide new clues and research directions for future research.Methods: Articles and reviews regarding herbal medicine in the treatment of CKD were retrieved from the Web of Science Core Collection on 23 May 2022. The R-bibliometrix, VOSviewer, and CiteSpace software were used to conduct the bibliometric and knowledge-map analysis.Results: In total, 5,920 authors at 1,330 institutions from 68 countries published 1,602 papers in 355 academic journals. China is the leader and pioneer in the research and application of herbal medicine in the field of CKD treatment. Beijing University of Chinese Medicine contributed the most publications. Ping Li (China-Japan Friendship Hospital) published the most articles, while Yingyong Zhao (Northwest University) had the most cocitations. However, cooperation among countries and the research institutions is not sufficient. Journal of Ethnopharmacology published the most research and application of herbal medicine in the treatment of CKD and was the most commonly co-cited journal. The most influential research hotspots about herbal medicine in the treatment of CKD focused on diabetic nephropathy-related research, Balkan endemic nephropathy, and pharmacokinetic study.Conclusion: Herbal medicine has a wide range of pharmacological activities and therapeutic value. The research and application of herbal medicine for the treatment of CKD, especially diabetic nephropathy, will remain a hot topic in the future.
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- 2022
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4. Antibacterial properties of lactoferrin: A bibliometric analysis from 2000 to early 2022
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Yunling Xu, Yuji Wang, Jiaolong He, and Wanping Zhu
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lactoferrin ,antibacterial ,bibliometrics ,hotspots ,research status ,COVID-19 ,Microbiology ,QR1-502 - Abstract
BackgroundHere, a bibliometric and knowledge map analysis are used to analyze the research hot spots and development trends regarding the antibacterial effect of lactoferrin (LF). By looking for research hot spots and new topics, we provide new clues and research directions for future research.MethodsArticles and reviews regarding the antibacterial effect of LF were retrieved and from the Web of Science Core Collection (WoSCC) on 25 June 2022. CiteSpace and VOSviewer were used to conduct the bibliometric and knowledge map analysis.ResultsIn total, 8,292 authors at 2,151 institutions from 86 countries published 1,923 articles in 770 academic journals. The United States was the leader regarding research on the antibacterial effects of LF, while the Netherlands was a pioneer in conducting research in this field. The University of California system contributed the most publications. Bolscher JGM published most articles, while Wayne Bellamy had most cocitations. However, there was insufficient cooperation among the various institutions and authors. BioMetals published most LF-antibacterial activity-related articles, whereas Infection and Immunity was most commonly cocited journal. The most influential research hot spots about the antibacterial effect of LF focused on antimicrobial peptides, casein, human milk, expression, and Escherichia coli-related research. The latest hot spots and research frontier included COVID-19, antibiofilm activity, and immune defense.ConclusionsLF is a multifunctional protein with a broad spectrum of antimicrobial activities. The related field of antibacterial properties of LF will remain a research hot spot in future.
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- 2022
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5. Anatomy and function of the vertebral column lymphatic network in mice
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Laurent Jacob, Ligia Simoes Braga Boisserand, Luiz Henrique Medeiros Geraldo, Jose de Brito Neto, Thomas Mathivet, Salli Antila, Besma Barka, Yunling Xu, Jean-Mickael Thomas, Juliette Pestel, Marie-Stéphane Aigrot, Eric Song, Harri Nurmi, Seyoung Lee, Kari Alitalo, Nicolas Renier, Anne Eichmann, and Jean-Leon Thomas
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Science - Abstract
The lymphatic vasculature is essential to maintain fluid homeostasis and immune surveillance, including in the brain where lymphatic vessels were only recently identified. Here, Jacob et al. provide an anatomical map of lymphatic vessels in the vertebral column, where they find these contribute to fluid drainage and immune responses.
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- 2019
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6. Underlying mechanisms of Solanum lyratum in the treatment of rheumatoid arthritis: insights from network pharmacology.
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Yunling Xu and Jiaolong He
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RHEUMATOID arthritis , *TREATMENT effectiveness , *SOLANUM , *GENETIC regulation , *CELLULAR signal transduction , *GLYCINE receptors - Abstract
To elucidate the active ingredients and potential mechanism of Solanum lyratum in the treatment of rheumatoid arthritis (RA), we employed a comprehensive strategy that combined network pharmacology and molecular docking. First, we systematically retrieved relevant compounds from S. lyratum documented in the literature. We obtained RA-related targets by querying GeneCards, DisGeNET, and the OMIM database. Subsequently, we constructed drug-compound-target and protein-protein interaction (PPI) networks to predict the promising protein targets of S. lyratum and identify the primary interactions between these protein targets and compounds. To validate our predicted candidate targets, we employed docking techniques. Finally, we conducted an in vitro intervention and validation using the ethyl acetate extract of S. lyratum on human RA synovial fibroblasts (MH7A). Our analysis identified a total of 41 potential active compounds and 126 intersecting pharmacological targets. GO enrichment analysis revealed that positive regulation of gene expression, response to hypoxia, and apoptotic processes were closely associated with S. lyratum treatment in RA. KEGG pathway analysis suggested that the TNF signaling pathway, IL-17 signaling pathway, PI3K-Akt signaling pathway, MAPK signaling pathway, and Toll-Like receptor signaling pathway might play a pivotal role in S. lyratum intervention in RA. Consequently, key targets could include AKT1, TP53, VEGF, CASP3, TNF, and IL6. Molecular docking analysis indicated that diosgenin, strychnine, solamargine, solamarine, solasodine, and ursolic acid exhibited strong binding affinities with STAT3, JUN, MAPK1, TNF, TP53, IL6, MAPK8, IL1B, MMP1, and MMP3. These active compounds in S. lyratum had the potential to regulate multiple signaling pathways and target molecules, thereby exerting preventive and therapeutic effects in RA. In our in vitro experiment, we observed that the ethyl acetate extract of S. lyratum inhibited the proliferation of MH7A cells and reduced the release of cytokines. These experimental results aligned with the predictions generated through the network pharmacology approach. This study not only provided a theoretical foundation for the use of S. lyratum in the treatment of RA but also offered valuable insights for further investigations into the action mechanisms of Chinese herbal extract compounds. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Analyzing the mechanism and experimental validation of Astilbe chinensis in the treatment of rheumatoid arthritis through network pharmacology.
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Ying Chen, Haixia Ying, Tingting Cai, and Yunling Xu
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RHEUMATOID arthritis ,NITRIC-oxide synthases ,GENE expression ,ANTI-inflammatory agents ,PROTEIN-protein interactions - Abstract
To unravel the active components and potential mechanisms of Astilbe chinensis in treating rheumatoid arthritis (RA), we employed a comprehensive strategy that combined network pharmacology and biological activity verification. Firstly, we identified the relevant compounds in A. chinensis from the literature, and RA-related targets were gathered through DisGeNET, GeneCards, and OMIM databases. Subsequently, compound-target and protein-protein interaction networks were constructed to predict the key compounds and promising protein targets of A. chinensis. Finally, these predictions were validated through in vitro anti-inflammatory activity experiments. A total of 29 potential active compounds and 117 intersecting pharmacological targets were identified. Among them, key active compounds included 3β,6β-dihydroxy olean-12-en-27-oic acid (astilbic acid), 3β-acetoxyolean-12-en-27-oic acid (3-acetyl oleanolic acid), 3β-hydroxyurs-12-en-27-oic acid, 4-O-galloylbergenin, and (+)/(-)-catechin. Key targets were identified as AKT1, MMP9, EGFR, CASP3, and HSP90AA1. GO enrichment analysis indicated that signal transduction, proteolysis, and negative regulation of the apoptotic process were closely associated with A. chinensis treatment in RA. KEGG pathway analysis indicated that pathways in cancer, osteoclast differentiation, and endocrine resistance might be crucial for A. chinensis intervention in RA. This finding suggested that multiple components in A. chinensis could regulate various signaling pathways and targets, playing preventive and therapeutic roles in RA. In vitro experiments demonstrated that A. chinensis extracts inhibited the secretion of inflammatory factors (NO, TNF-α, and IL-6) and significantly suppressed the expression of inducible nitric oxide synthase (iNOS), IL-6, and TNF-α mRNA in LPS-induced RAW 264.7 cells. Collectively, our findings not only established the theoretical basis for the efficacy of A. chinensis in treating RA but also provided a direction for subsequent research. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Principled leveraging of external data in the evaluation of diagnostic devices via the propensity score‐integrated composite likelihood approach
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Changhong Song, Heng Li, Wei‐Chen Chen, Nelson Lu, Ram Tiwari, Chenguang Wang, Yunling Xu, and Lilly Q. Yue
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Pharmacology ,Statistics and Probability ,Pharmacology (medical) - Published
- 2023
9. Improving precision and power in randomized trials with a two‐stage study design: Stratification using clustering method
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Xuan Ye, Nelson Lu, and Yunling Xu
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Pharmacology ,Statistics and Probability ,Pharmacology (medical) - Abstract
In a randomized controlled trial (RCT), it is possible to improve precision and power and reduce sample size by appropriately adjusting for baseline covariates. There are multiple statistical methods to adjust for prognostic baseline covariates, such as an ANCOVA method. In this paper, we propose a clustering-based stratification method for adjusting for the prognostic baseline covariates. Clusters (strata) are formed only based on prognostic baseline covariates, not outcome data nor treatment assignment. Therefore, the clustering procedure can be completed prior to the availability of outcome data. The treatment effect is estimated in each cluster, and the overall treatment effect is derived by combining all cluster-specific treatment effect estimates. The proposed implementation of the procedure is described. Simulations studies and an example are presented.
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- 2022
10. Some Thoughts on the Use of Predictive Probability in Clinical Trials
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Heng Li, Manuela Buzoianu, Adrijo Chakraborty, Li Ming Dong, Chia-Wen Ko, Xuefeng Li, Nelson Lu, Yanping Qu, Yunling Xu, and Xu Yan
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Public Health, Environmental and Occupational Health ,Pharmacology (medical) ,Pharmacology, Toxicology and Pharmaceutics (miscellaneous) - Published
- 2023
11. Estimands in observational studies: Some considerations beyond <scp>ICH E9</scp> ( <scp>R1</scp> )
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Heng Li, Chenguang Wang, Wei‐Chen Chen, Nelson Lu, Changhong Song, Ram Tiwari, Yunling Xu, and Lilly Q. Yue
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Pharmacology ,Statistics and Probability ,Observational Studies as Topic ,Models, Statistical ,Research Design ,Data Interpretation, Statistical ,Humans ,Pharmacology (medical) - Abstract
The document ICH E9 (R1) has brought much attention to the concept of estimand in the clinical trials community. ICH stands for International Conference for Harmonization. In this article, we draw attention to one facet of estimand that is not discussed in that document but is crucial in the context of observational studies, namely weighting for covariate balance. How weighting schemes are connected to estimand, or more specifically to one of its five attributes identified in ICH E9 (R1), the attribute of population, is illustrated using the Rubin Causal Model. Three estimands are examined from both theoretical and practical perspectives. Factors that may be considered in choosing among these estimands are discussed.
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- 2022
12. Propensity score-integrated power prior approach for augmenting the control arm of a randomized controlled trial by incorporating multiple external data sources
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Chenguang Wang, Lilly Q. Yue, Heng Li, Ram C. Tiwari, Changhong Song, Wei-Chen Chen, Nelson Lu, and Yunling Xu
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Pharmacology ,Statistics and Probability ,Computer science ,Information Storage and Retrieval ,Bayesian inference ,Power (physics) ,law.invention ,External data ,Control arm ,Randomized controlled trial ,Research Design ,law ,Covariate ,Statistics ,Propensity score matching ,Humans ,Pharmacology (medical) ,Treatment effect ,Propensity Score - Abstract
In this paper, a propensity score-integrated power prior approach is developed to augment the control arm of a two-arm randomized controlled trial (RCT) with subjects from multiple external data sources such as real-world data (RWD) and historical clinical studies containing subject-level outcomes and covariates. The propensity scores for the subjects in the external data sources versus the subjects in the RCT are first estimated, and then subjects are placed in different strata based on their estimated propensity scores. Within each propensity score stratum, a power prior is formulated with the information contributed by the external data sources, and Bayesian inference on the treatment effect is obtained. The proposed approach is implemented under the two-stage study design framework utilizing the outcome-free principle to ensure the integrity of a study. An illustrative example is provided to demonstrate the implementation of the proposed approach.
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- 2021
13. Leveraging real‐world evidence for determining performance goals for medical device studies
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Tingting Bao, Ram Tiwari, Nelson Lu, Heng Li, Gary L. Rosner, Wei Chen Chen, Lilly Q. Yue, Yunling Xu, and Chenguang Wang
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Statistics and Probability ,Medical device ,Epidemiology ,Computer science ,Real world evidence ,Outcome (game theory) ,Clinical trial ,Clinical Practice ,Patient population ,Risk analysis (engineering) ,Research Design ,Medical product ,Humans ,Entropy (information theory) ,Goals - Abstract
Performance goals are numerical target values pertaining to effectiveness or safety endpoints in single-arm medical device clinical studies. Typically, performance goals are determined at the planning stage of the investigational study under consideration based on summarized outcome information from existing relevant clinical trials. In recent years, there is a growing interest in leveraging real-world evidence in medical product development. In this article, we introduce a new method for proposing performance goals by leveraging real-world evidence. The method applies entropy balancing to address possible patient dissimilarities between the study's target patient population and existing real-world patients, and can take into account operation differences between clinical studies and real-world clinical practice. An illustrative example is provided to demonstrate how to implement the proposed method for performance goal determination while leveraging real-world evidence.
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- 2021
14. Rejoinder to Letter to the Editor—Selecting an Optimal Design for a Nonrandomized Comparative Study: A Commentary on 'Some Considerations on Design and Analysis Plan on a Nonrandomized Comparative Study Utilizing Propensity Score Methodology for Medical Device Premarket Evaluation'
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Nelson Lu, Yunling Xu, and Lilly Q. Yue
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Statistics and Probability ,Pharmaceutical Science - Published
- 2022
15. Leverage multiple real-world data sources in single-arm medical device clinical studies
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Heng Li, Changhong Song, Lilly Q. Yue, Yunling Xu, Nelson Lu, Chenguang Wang, Wei Chen Chen, and Ram Tiwari
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Statistics and Probability ,Quasi-maximum likelihood ,Medical device ,Computer science ,Information Storage and Retrieval ,computer.software_genre ,01 natural sciences ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Covariate ,Humans ,Leverage (statistics) ,Computer Simulation ,Pharmacology (medical) ,Prospective Studies ,030212 general & internal medicine ,0101 mathematics ,Propensity Score ,Pharmacology ,Research Design ,Propensity score matching ,Data mining ,Outcome data ,Real world data ,computer ,Weighted arithmetic mean - Abstract
The interest in utilizing real-world data (RWD) has been considerably increasing in medical product development and evaluation. With proper usage and analysis of high-quality real-world data, real-world evidence (RWE) can be generated to inform regulatory and healthcare decision-making. This paper proposes a study design and data analysis approach for a prospective, single-arm clinical study that is supplemented with patients from multiple real-world data sources containing patient-level covariate and outcome data. After the amount of information to be borrowed from each real-world data source is determined, the propensity score-integrated composite likelihood method is applied to obtain an estimate of the parameter of interest based on data from the prospective clinical study and this real-world data source. This method is applied to each real-world data source. The final estimate of the parameter of interest is then obtained by taking a weighted average of all these estimates. The performance of the proposed approach is evaluated via a simulation study. A hypothetical example is presented to illustrate how to implement the proposed approach.
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- 2021
16. Evaluation of diagnostic tests for low prevalence diseases: a statistical approach for leveraging real-world data to accelerate the study
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Changhong Song, Lilly Q. Yue, Ram Tiwari, Heng Li, Yunling Xu, Chenguang Wang, Nelson Lu, and Wei Chen Chen
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Statistics and Probability ,Quasi-maximum likelihood ,Computer science ,Machine learning ,computer.software_genre ,Real world evidence ,01 natural sciences ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,mental disorders ,Prevalence ,Statistical inference ,Humans ,Pharmacology (medical) ,Prospective Studies ,030212 general & internal medicine ,Sensitivity (control systems) ,0101 mathematics ,Propensity Score ,Pharmacology ,Diagnostic Tests, Routine ,business.industry ,Diagnostic test ,Bayes Theorem ,Test (assessment) ,Propensity score matching ,Artificial intelligence ,business ,computer ,Real world data - Abstract
The evaluation of diagnostic tests usually involves statistical inference for its sensitivity. As sensitivity is defined as the probability that the test result will be positive when the target condition is present, the key study design consideration of sample size is the determination of the number of subjects with the target condition such that the estimation has adequate precision, or the hypothesis testing has adequate power. Traditionally, one may rely on prospective screening of subjects to obtain the required sample size, which means that if the prevalence of the disease is very low, a large number of subjects would need to be screened, increasing the study duration and cost. In this paper, we consider the possibility of substantially reducing the length and cost of a clinical study by leveraging subjects from a real-world data (RWD) source, focusing specifically on the diagnostic test for the cancer of interest. Using the propensity score methodology, we developed a procedure which ensures that the real-world subjects being leveraged are similar to their prospectively enrolled counterparts, thereby making the leveraging more justified. The procedure allows the down-weighting of the real-world subjects, which can be achieved by either using a Frequentist's method based on the composite likelihood or a Bayesian method based on the power prior. The proposed approach can be applied to the evaluation of any diagnostic test and it is not limited to the current clinical study regarding a cancer diagnostic test. Notably, this paper is in close alignment with a recently released draft framework by the Medical Device Innovation Consortium (MDIC) on real-world clinical evidence and
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- 2021
17. Mitigating Study Power Loss Caused by Clinical Trial Disruptions Due to the COVID-19 Pandemic: Leveraging External Data via Propensity Score-Integrated Approaches
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Yunling Xu, Chenguang Wang, Nelson Lu, Wei Chen Chen, Ram Tiwari, Heng Li, Lilly Q. Yue, and Changhong Song
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Statistics and Probability ,Power loss ,medicine.medical_specialty ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Pharmaceutical Science ,01 natural sciences ,Clinical trial ,010104 statistics & probability ,03 medical and health sciences ,External data ,0302 clinical medicine ,Propensity score matching ,Pandemic ,medicine ,030212 general & internal medicine ,0101 mathematics ,Intensive care medicine ,business ,Real world data - Abstract
The spread of COVID-19 has created tremendous challenges to ongoing clinical studies essential to finding effective treatments and cures for a myriad of diseases, with some studies having suspended...
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- 2021
18. 3D-imaging reveals conserved cerebrospinal fluid drainage via meningeal lymphatic vasculature in mice and humans
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Laurent Jacob, Jose de Brito Neto, Stephanie Lenck, Celine Corcy, Farhat Benbelkacem, Luiz Henrique Geraldo, Yunling Xu, Jean-Mickael Thomas, Marie-Renee El Kamouh, Marie-Claude Potier, Stephane Haik, Stephane Lehericy, Anne Eichmann, and Jean-Leon Thomas
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Meningeal lymphatic vessels (MLVs) contribute to waste product elimination and immune surveillance in brain tissues. MLVs were identified in the dorsal and caudo-basal regions of the dura mater, where they ensure the clearance of cerebrospinal fluid (CSF). Whether MLVs exist in the complex anterior part of the murine and human skull, and how they connect with the glymphatic system and extracranial lymphatic vasculature remained unclear. Here, we generated three-dimensional (3D) maps of MLV drainage by light-sheet fluorescence microscopy (LSFM) imaging of mouse whole-head preparations following fluorescent OVA-A555 tracer injections into the CSF. In humans, we performed real-time magnetic resonance vessel wall imaging (MR-VWI) after systemic gadobutrol injections. We observed a conserved 3D-anatomy of MLVs in mice and humans, and we discovered an extended anterior network around the dural cavernous sinus including multiple capillary beds and exit routes through the foramina of emissary veins. MR-VWI may provide a diagnostic tool for patients with CSF drainage defects and neurological diseases.Short abstractWe established the 3D-anatomy of meningeal lymphatic vasculature and associated CSF drainage by postmortem light-sheet imaging in mice and by real-time magnetic resonance imaging in humans, demonstrating conserved lymphatic circuitries in contact with dural venous sinuses.
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- 2022
19. Conserved meningeal lymphatic drainage circuits in mice and humans
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Laurent Jacob, Jose de Brito Neto, Stephanie Lenck, Celine Corcy, Farhat Benbelkacem, Luiz Henrique Geraldo, Yunling Xu, Jean-Mickael Thomas, Marie-Renee El Kamouh, Myriam Spajer, Marie-Claude Potier, Stephane Haik, Michel Kalamarides, Bruno Stankoff, Stephane Lehericy, Anne Eichmann, Jean-Leon Thomas, Institut du Cerveau = Paris Brain Institute (ICM), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Sorbonne Université (SU)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Paris-Centre de Recherche Cardiovasculaire (PARCC (UMR_S 970/ U970)), Hôpital Européen Georges Pompidou [APHP] (HEGP), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris Cité (UPCité), Universidade Federal do Rio de Janeiro (UFRJ), Siemens Healthcare [France], Siemens AG [Munich], Yale University [New Haven], Service de Neurologie [CHU Saint-Antoine], CHU Saint-Antoine [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Center for NeuroImaging Research-Human MRI Neuroimaging core facility for clinical research [ICM Paris] (CENIR), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Sorbonne Université (SU)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-CHU Pitié-Salpêtrière [AP-HP], Service de Neuroradiologie [CHU Pitié-Salpêtrière], and JACOB, Laurent
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Lymphatic System ,Mice ,Meninges ,[SCCO.NEUR]Cognitive science/Neuroscience ,[SCCO.NEUR] Cognitive science/Neuroscience ,Immunology ,Immunology and Allergy ,Animals ,Humans ,Glymphatic System ,Magnetic Resonance Imaging ,Lymphatic Vessels - Abstract
International audience; Meningeal lymphatic vessels (MLVs) were identified in the dorsal and caudobasal regions of the dura mater, where they ensure waste product elimination and immune surveillance of brain tissues. Whether MLVs exist in the anterior part of the murine and human skull and how they connect with the glymphatic system and extracranial lymphatics remained unclear. Here, we used light-sheet fluorescence microscopy (LSFM) imaging of mouse whole-head preparations after OVA-A555 tracer injection into the cerebrospinal fluid (CSF) and performed real-time vessel-wall (VW) magnetic resonance imaging (VW-MRI) after systemic injection of gadobutrol in patients with neurological pathologies. We observed a conserved three-dimensional anatomy of MLVs in mice and humans that aligned with dural venous sinuses but not with nasal CSF outflow, and we discovered an extended anterior MLV network around the cavernous sinus, with exit routes through the foramina of emissary veins. VW-MRI may provide a diagnostic tool for patients with CSF drainage defects and neurological diseases.
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- 2022
20. Propensity score-integrated approach to survival analysis: leveraging external evidence in single-arm studies
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Wei-Chen Chen, Nelson Lu, Chenguang Wang, Heng Li, Changhong Song, Ram Tiwari, Yunling Xu, and Lilly Q. Yue
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Data Analysis ,Pharmacology ,Statistics and Probability ,Research Design ,Humans ,Computer Simulation ,Pharmacology (medical) ,Propensity Score ,Survival Analysis - Abstract
External data, referred to as data external to the traditional clinical study being planned, include but are not limited to real-world data (RWD) and data collected from clinical studies being conducted in the past or in other countries. The external data are sometimes leveraged to augment a single-arm, prospectively designed study when appropriate. In such an application, recently developed propensity score-integrated approaches including PSPP and PSCL can be used for study design and data analysis when the clinical outcomes are binary or continuous. In this paper, the propensity score-integrated Kaplan-Meier (PSKM) method is proposed for a similar situation but the outcome of interest is time-to-event. The propensity score methodology is used to select external subjects that are similar to those in the current study in terms of baseline covariates and to stratify the selected subjects from both data sources into more homogeneous strata. The stratum-specific PSKM estimators are obtained based on all subjects in the stratum with the external data being down-weighted, and then these estimators are combined to obtain an overall PSKM estimator. A simulation study is conducted to assess the performance of the PSKM method, and an illustrative example is presented to demonstrate how to implement the proposed method.
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- 2022
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21. Novel statistical approaches and applications in leveraging real-world data in regulatory clinical studies
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Heng Li, Wei Chen Chen, Nelson Lu, Lilly Q. Yue, Ram Tiwari, Chenguang Wang, and Yunling Xu
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business.industry ,Computer science ,030503 health policy & services ,Health Policy ,Public Health, Environmental and Occupational Health ,Information technology ,Bayesian inference ,Data science ,Health administration ,03 medical and health sciences ,0302 clinical medicine ,Frequentist inference ,Health care ,Propensity score matching ,Leverage (statistics) ,030212 general & internal medicine ,0305 other medical science ,business ,Real world data - Abstract
In medical product development, there has been a growing interest in utilizing real-world data which have become abundant owing to advances in biomedical science, information technology and engineering. High-quality real-world data may be utilized to generate real-world evidence for regulatory or healthcare decision-making. We discuss propensity score-based approaches for leveraging patients from a real-world data source to construct a control group for a non-randomized comparative study or to augment a single-arm or randomized prospective investigational clinical study. The proposed propensity score-based approaches leverage real-world patients that are similar to those prospectively enrolled into the investigational clinical study in terms of baseline characteristics. Either frequentist or Bayesian inference can then be applied for outcome data analysis, with the option of down-weighting information from the real-world data source. Examples based on pre-market regulatory review experience are provided to illustrate the implementation of the proposed approaches.
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- 2020
22. Use of Weighted Performance Goals in Prospective Single-Arm Clinical Studies Designed to Assess the Safety and Effectiveness of Medical Devices
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Yunling Xu, Nelson Lu, and Heng Li
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Statistics and Probability ,medicine.medical_specialty ,Preclinical testing ,business.industry ,medicine ,Pharmaceutical Science ,Medical physics ,business ,Commercialization - Abstract
In addition to extensive preclinical testing, commercialization of medical devices in the United States under some circumstances may be supported with clinical data derived from single arm studies ...
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- 2020
23. Propensity score-integrated composite likelihood approach for augmenting the control arm of a randomized controlled trial by incorporating real-world data
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Chenguang Wang, Lilly Q. Yue, Nelson Lu, Ram Tiwari, Yunling Xu, Heng Li, and Wei Chen Chen
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Statistics and Probability ,Quasi-maximum likelihood ,Computer science ,Real world evidence ,01 natural sciences ,law.invention ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Randomized controlled trial ,law ,Pragmatic Clinical Trials as Topic ,Covariate ,Statistics ,Humans ,Computer Simulation ,Pharmacology (medical) ,Registries ,030212 general & internal medicine ,0101 mathematics ,Propensity Score ,Randomized Controlled Trials as Topic ,Heart Failure ,Pharmacology ,Likelihood Functions ,Control arm ,Propensity score matching ,Real world data - Abstract
In this paper, a propensity score-integrated composite likelihood (PSCL) approach is developed for cases in which the control arm of a two-arm randomized controlled trial (RCT) (treated vs control) is augmented with patients from real-world data (RWD) containing both clinical outcomes and covariates at the patient-level. RWD patients who were treated with the same therapy as the control arm of the RCT are considered for the augmentation. The PSCL approach first estimates the propensity score for every patient as the probability of the patient being in the RCT rather than the RWD, and then stratifies all patients into strata based on the estimated propensity scores. Within each propensity score stratum, a composite likelihood function is specified and utilized to down-weight the information contributed by the RWD source. Estimates of the stratum-specific parameters are obtained by maximizing the composite likelihood function. These stratum-specific estimates are then combined to obtain an overall population-level estimate of the parameter of interest. The performance of the proposed approach is evaluated via a simulation study. A hypothetical two-arm RCT and a hypothetical RWD source are used to illustrate the implementation of the proposed approach.
- Published
- 2020
24. Protective Effect of the Pearl Extract from Pinctada fucata martensii Dunker on UV-Induced Photoaging in Mice
- Author
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Zhongmin Zhang, Yunling Xu, Ruicheng Lai, Huiyuan Deng, Fengling Zhou, Peiyan Wang, Xiubing Pang, Guoxin Huang, Xin Chen, Haoge Lin, Yong Lin, Zhenxing Chen, and Jiang Lin
- Subjects
Plant Extracts ,Ultraviolet Rays ,Bioengineering ,General Chemistry ,General Medicine ,Biochemistry ,Calcium Carbonate ,Skin Aging ,Mice ,Molecular Medicine ,Animals ,Pinctada ,Molecular Biology ,Skin - Abstract
Although the effect of pearl powder has been recognized for more than a thousand years from healthcare to beauty care, there has yet to be an in-depth understanding of its anti-photoaging effect. In the present study, the protective effect of pearl extract (PE) on UV-induced photoaging in mice was evaluated. First, the amino acid analysis of PE was carried out. Then, different dosages of pearl extract gel (PEG) were applied topically on the shaved dorsal skins regions of mice before UV irradiation. Skin physiological and histological analysis, antioxidant enzymes and inflammatory factor test were used to evaluate the anti-photoaging effect of PEG. The results showed that PEG contained 14 amino acids, and could inhibit UV-irritated skin wrinkles, laxity, thickness, and dryness. Moreover, PEG upregulated the activities of CAT, GSH-Px, SOD and decreased MDA level, and suppressed the production of IL-1β, IL-6, PGE
- Published
- 2021
25. Vascular and hormonal interactions in primary aldosteronism
- Author
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Alaa Abdellatif, Nicolo Faedda, Isabelle Giscos-Douriez, Yunling Xu, Fabio Fernandes-Rosa, Sheerazed Boulkroun, and Maria Christina Zennaro
- Subjects
Cardiology and Cardiovascular Medicine - Published
- 2022
26. SLIT2/ROBO signaling in tumor-associated microglia and macrophages drives glioblastoma immunosuppression and vascular dysmorphia
- Author
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Joost Dejaegher, Anne Eichmann, Maite Verreault, Flavia Regina Souza Lima, Andreas Bikfalvi, Marc Sanson, Thomas Mathivet, Q. Richard Lu, Corinne Lesaffre, Yunling Xu, Luiz Henrique Medeiros Geraldo, Lien Solie, Ahmed Idbaih, Justine Rudewicz, Jean-Leon Thomas, Thomas Viel, Camille Knosp, Laurent Jacob, Rohit Rao, Bertrand Tavitian, Nolwenn Lemaire, Nawal Maïssa, Thomas Daubon, Steven De Vleeschouwer, Laurence Pibouin-Fragner, Institut de biochimie et génétique cellulaires (IBGC), and Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[SDV]Life Sciences [q-bio] ,medicine.medical_treatment ,Nerve Tissue Proteins ,Biology ,Brain cancer ,Macrophage chemotaxis ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Vascular Biology ,Glioma ,Immune Tolerance ,Tumor Microenvironment ,medicine ,Animals ,Humans ,Macrophage ,Receptors, Immunologic ,ComputingMilieux_MISCELLANEOUS ,PI3K/AKT/mTOR pathway ,030304 developmental biology ,0303 health sciences ,Tumor microenvironment ,Gene knockdown ,Microglia ,Brain Neoplasms ,Macrophages ,General Medicine ,Immunotherapy ,Prognosis ,medicine.disease ,3. Good health ,Gene Expression Regulation, Neoplastic ,Mice, Inbred C57BL ,medicine.anatomical_structure ,Oncology ,Gene Knockdown Techniques ,030220 oncology & carcinogenesis ,Disease Progression ,Cancer research ,Heterografts ,Intercellular Signaling Peptides and Proteins ,Glioblastoma ,Research Article ,Signal Transduction - Abstract
SLIT2 is a secreted polypeptide that guides migration of cells expressing Roundabout 1 and 2 (ROBO1 and ROBO2) receptors. Herein, we investigated SLIT2/ROBO signaling effects in gliomas. In patients with glioblastoma (GBM), SLIT2 expression increased with malignant progression and correlated with poor survival and immunosuppression. Knockdown of SLIT2 in mouse glioma cells and patient-derived GBM xenografts reduced tumor growth and rendered tumors sensitive to immunotherapy. Tumor cell SLIT2 knockdown inhibited macrophage invasion and promoted a cytotoxic gene expression profile, which improved tumor vessel function and enhanced efficacy of chemotherapy and immunotherapy. Mechanistically, SLIT2 promoted microglia/macrophage chemotaxis and tumor-supportive polarization via ROBO1- and ROBO2-mediated PI3K-γ activation. Macrophage Robo1 and Robo2 deletion and systemic SLIT2 trap delivery mimicked SLIT2 knockdown effects on tumor growth and the tumor microenvironment (TME), revealing SLIT2 signaling through macrophage ROBOs as a potentially novel regulator of the GBM microenvironment and immunotherapeutic target for brain tumors. ispartof: JOURNAL OF CLINICAL INVESTIGATION vol:131 issue:16 ispartof: location:United States status: published
- Published
- 2021
27. Propensity score-integrated power prior approach for incorporating real-world evidence in single-arm clinical studies
- Author
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Chenguang Wang, Nelson Lu, Ram Tiwari, Yunling Xu, Heng Li, Lilly Q. Yue, and Wei Chen Chen
- Subjects
Statistics and Probability ,Computer science ,Big data ,Bayesian probability ,Bayesian inference ,Machine learning ,computer.software_genre ,01 natural sciences ,Scientific evidence ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Pragmatic Clinical Trials as Topic ,Covariate ,Humans ,Leverage (statistics) ,Pharmacology (medical) ,030212 general & internal medicine ,0101 mathematics ,Propensity Score ,Pharmacology ,Biological Products ,business.industry ,Information technology ,Bayes Theorem ,Propensity score matching ,Artificial intelligence ,business ,computer - Abstract
We are now at an amazing time for medical product development in drugs, biological products and medical devices. As a result of dramatic recent advances in biomedical science, information technology and engineering, ``big data'' from health care in the real-world have become available. Although big data may not necessarily be attuned to provide the preponderance of evidence to a clinical study, high-quality real-world data can be transformed into scientific evidence for regulatory and healthcare decision-making using proven analytical methods and techniques, such as propensity score methodology and Bayesian inference. In this paper, we extend the Bayesian power prior approach for a single-arm study (the current study) to leverage external real-world data. We use propensity score methodology to pre-select a subset of real-world data containing patients that are similar to those in the current study in terms of covariates, and to stratify the selected patients together with those in the current study into more homogeneous strata. The power prior approach is then applied in each stratum to obtain stratum-specific posterior distributions, which are combined to complete the Bayesian inference for the parameters of interest. We evaluate the performance of the proposed method as compared to that of the ordinary power prior approach by simulation and illustrate its implementation using a hypothetical example, based on our regulatory review experience.
- Published
- 2019
28. Homogeneity assessment for pivotal medical device clinical studies
- Author
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Heng Li, Ram C. Tiwari, Xu Yan, Nelson Lu, Lilly Q. Yue, Xuefeng Li, Hong Lu, Jianxiong Chu, Li Ming Dong, Yunling Xu, Vandana Mukhi, Chul Ahn, and Rajesh Nair
- Subjects
Male ,Statistics and Probability ,medicine.medical_specialty ,Medical device ,01 natural sciences ,law.invention ,Clinical study ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Randomized controlled trial ,law ,Humans ,Medicine ,Pharmacology (medical) ,Treatment effect ,Medical physics ,030212 general & internal medicine ,0101 mathematics ,Randomized Controlled Trials as Topic ,Pharmacology ,Clinical Trials as Topic ,business.industry ,Homogeneity (statistics) ,Clinical judgment ,Equipment and Supplies ,Female ,business - Abstract
A question that routinely arises in medical device clinical studies is the homogeneity across demographic subgroups, geographical regions, or investigational sites of the enrolled patients in terms of treatment effects or outcome variables. The main objective of this paper is to discuss statistical concepts and methods for the assessment of such homogeneity and to provide the practitioner a statistical framework and points to consider in conducting homogeneity assessment. Demographic subgroups, geographical regions, and investigational sites are discussed separately as each has its unique issues. Specific considerations are also given to randomized controlled trials, non-randomized comparative studies, and single-arm studies. We point out that judicious use of statistical methods, in conjunction with sound clinical judgment, is essential in handling the issue of homogeneity of treatment effect in medical device clinical studies.
- Published
- 2019
29. Some Considerations on Design and Analysis Plan on a Nonrandomized Comparative Study Using Propensity Score Methodology for Medical Device Premarket Evaluation
- Author
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Yunling Xu, Lilly Q. Yue, and Nelson Lu
- Subjects
Statistics and Probability ,medicine.medical_specialty ,Medical device ,Computer science ,Pharmaceutical Science ,Plan (drawing) ,01 natural sciences ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Estimand ,Propensity score matching ,medicine ,Medical physics ,030212 general & internal medicine ,0101 mathematics ,Real world data - Abstract
Nonrandomized comparative studies have been widely proposed and conducted in the premarket safety and effectiveness evaluation of medical devices. A typical case is to compare results of a clinical...
- Published
- 2019
30. Good statistical practice in utilizing real-world data in a comparative study for premarket evaluation of medical devices
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Nelson Lu, Yunling Xu, and Lilly Q. Yue
- Subjects
Pharmacology ,Statistics and Probability ,Computer science ,Real world evidence ,01 natural sciences ,Data science ,Data Accuracy ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Bias ,Research Design ,Data Interpretation, Statistical ,Propensity score matching ,Device Approval ,Humans ,Pharmacology (medical) ,Observational study ,030212 general & internal medicine ,0101 mathematics ,Propensity Score ,Objectivity (science) ,Real world data ,Randomized Controlled Trials as Topic - Abstract
Observational (non-randomized) comparative studies have been adopted in the pre-market safety/effectiveness evaluation of medical devices. There has been an increased interest in utilizing this design with the growing available real-world data. However, in such studies, biases that are introduced in every stage and aspect of study need to be addressed. Otherwise, the objectivity of study design and validity of study results will be compromised. In this paper, challenges and opportunities are discussed from the regulatory perspective. Considerations and good statistical practice to mitigate the potential bias are presented.
- Published
- 2019
31. Oxygen-enriched crumpled graphene-based symmetric supercapacitor with high gravimetric and volumetric performances
- Author
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Yunling Xu, Jiajia Zhu, Shengyang Dong, Xiaogang Zhang, Hongshuai Guo, and Xiaoxia Lu
- Subjects
Supercapacitor ,Aqueous solution ,Graphene ,General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,0104 chemical sciences ,Analytical Chemistry ,law.invention ,Sphere packing ,Chemical engineering ,chemistry ,law ,Electrochemistry ,Gravimetric analysis ,0210 nano-technology ,Porosity ,Carbon - Abstract
Supercapacitors (SCs) with high gravimetric and volumetric performances are highly demanded for diverse applications, but still remain challenge to achieve for traditional porous carbon materials due to the unbalance between porous properties and high density. Herein, we report a novel oxygen-enriched crumpled graphene (OCGN) with high density prepared through a simple and facile strategy. The as-prepared OCGN possesses several advantageous features of abundant stable active oxygen-containing functional groups (17.26%), high packing density (1.28 g cm−3) and facile ion channel, resulting in high gravimetric and volumetric specific capacitance (300.5 F g−1, 384.6 F cm−3), outstanding rate performance and cyclic stability. In addition, the assembled symmetric SC exhibits a large gravimetric and volumetric energy density of 20.4 Wh kg−1 and 26.1 Wh L−1 in aqueous electrolyte, which is higher than majority of previously reported carbon-based aqueous SCs. The encouraging results demonstrate that designing oxygen-enriched carbon materials with high density may be a novel strategy to realize both high gravimetric and volumetric performance.
- Published
- 2019
32. Augmenting Both Arms of a Randomized Controlled Trial Using External Data: An Application of the Propensity Score-Integrated Approaches
- Author
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Heng Li, Lilly Q. Yue, Ram Tiwari, Nelson Lu, Wei Chen Chen, Yunling Xu, Chenguang Wang, and Changhong Song
- Subjects
0301 basic medicine ,Statistics and Probability ,Quasi-maximum likelihood ,Computer science ,Bayesian probability ,Power prior ,Machine learning ,computer.software_genre ,01 natural sciences ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Article ,law.invention ,Composite likelihood ,010104 statistics & probability ,03 medical and health sciences ,External data ,Randomized controlled trial ,law ,Frequentist inference ,0101 mathematics ,business.industry ,030104 developmental biology ,Outcome-free design ,Propensity score matching ,Artificial intelligence ,Biostatistics ,Augment ,business ,computer - Abstract
Leveraging external data is a topic that have recently received much attention. The propensity score-integrated approaches are a methodological innovation for this purpose. In this paper we adapt these approaches, originally introduced to augment single-arm studies with external data, for the augmentation of both arms of a randomized controlled trial (RCT) with external data. After recapitulating the basic ideas, we provide a step-by-step tutorial of how to implement the propensity score-integrated approaches, from study design to outcome analysis, in the RCT setting in such a way that the study integrity and objectively are maintained. Both the Bayesian (power prior) approach and the frequentist (composite likelihood) approach are included. Some extensions and variations of these approaches are also outlined at the end of this paper.
- Published
- 2021
33. Dynamic Immunotherapy Study in Brain Tumor-Bearing Mice
- Author
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Thomas Mathivet, Yunling Xu, and Luiz Henrique Medeiros Geraldo
- Subjects
Bearing (mechanical) ,law ,business.industry ,medicine.medical_treatment ,medicine ,Brain tumor ,Cancer research ,Immunotherapy ,medicine.disease ,business ,law.invention - Published
- 2020
34. Propensity score-integrated composite likelihood approach for incorporating real-world evidence in single-arm clinical studies
- Author
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Nelson Lu, Yunling Xu, Chenguang Wang, Ram Tiwari, Wei Chen Chen, Heng Li, and Lilly Q. Yue
- Subjects
Statistics and Probability ,Quasi-maximum likelihood ,Computer science ,Machine learning ,computer.software_genre ,Real world evidence ,01 natural sciences ,Outcome (game theory) ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Covariate ,Pragmatic Clinical Trials as Topic ,Humans ,Pharmacology (medical) ,Computer Simulation ,030212 general & internal medicine ,0101 mathematics ,Propensity Score ,Pharmacology ,Data source ,Likelihood Functions ,business.industry ,Information technology ,Function (mathematics) ,Data Interpretation, Statistical ,Propensity score matching ,Artificial intelligence ,business ,computer - Abstract
In medical product development, there has been an increased interest in utilizing real-world data which have become abundant with recent advances in biomedical science, information technology, and engineering. High-quality real-world data may be analyzed to generate real-world evidence that can be utilized in the regulatory and healthcare decision-making. In this paper, we consider the case in which a single-arm clinical study, viewed as the primary data source, is supplemented with patients from a real-world data source containing both clinical outcome and covariate data at the patient-level. Propensity score methodology is used to identify real-world data patients that are similar to those in the single-arm study in terms of the baseline characteristics, and to stratify these patients into strata based on the proximity of the propensity scores. In each stratum, a composite likelihood function of a parameter of interest is constructed by down-weighting the information from the real-world data source, and an estimate of the stratum-specific parameter is obtained by maximizing the composite likelihood function. These stratum-specific estimates are then combined to obtain an overall population-level estimate of the parameter of interest. The performance of the proposed approach is evaluated via a simulation study. A hypothetical example based on our experience is provided to illustrate the implementation of the proposed approach.
- Published
- 2019
35. Incorporating a companion test into the noninferiority design of medical device trials
- Author
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Nelson Lu, Yunling Xu, and Ying Yang
- Subjects
Statistics and Probability ,Medical device ,Computer science ,Equivalence Trials as Topic ,Biostatistics ,Risk Assessment ,01 natural sciences ,Cardiac Catheters ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Device Approval ,Humans ,Pharmacology (medical) ,030212 general & internal medicine ,0101 mathematics ,Pharmacology ,Design stage ,Investigational Device ,Arrhythmias, Cardiac ,Active control ,Test (assessment) ,Treatment Outcome ,Risk analysis (engineering) ,Research Design ,Data Interpretation, Statistical ,Transparency (graphic) ,Catheter Ablation - Abstract
Noninferiority trials are commonly utilized to evaluate the safety and effectiveness of medical devices. It could happen that the noninferiority hypothesis is rejected while the performance of the active control is clinically not satisfactory. This may pose a great challenge when making a regulatory decision. To avoid such a difficult situation, we propose to conduct a companion test to assess the performance of the active control when testing the main noninferiority hypothesis and to incorporate such a test into the study design. Under our proposal, the noninferiority of the investigational device to the active control can only be claimed when both hypotheses are rejected. The operating characteristics of the proposed study design based on these two tests can be fully evaluated at the design stage. This proposed approach is aimed to facilitate regulatory decision making in a more transparent manner.
- Published
- 2018
36. Surface-functionalized graphene-based quasi-solid-state Na-ion hybrid capacitors with excellent performance
- Author
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Hui Dou, Yunling Xu, Xiaogang Zhang, Shengyang Dong, and Langyuan Wu
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,Graphene ,Energy Engineering and Power Technology ,Nanotechnology ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Capacitance ,Energy storage ,0104 chemical sciences ,law.invention ,Capacitor ,law ,Electrode ,General Materials Science ,0210 nano-technology ,Quasi-solid - Abstract
Simultaneous integration of high power density, high energy density, long cycle life and superior safety in a single energy storage system is still a huge challenge. Addressing this issue requires the design of new energy storage systems with novel electrodes. Herein, we propose a novel electrochemical energy storage device called a quasi-solid-state Na-ion hybrid capacitor (QSS–NIC) based on surface oxygen-functionalized crumpled graphene (OCG) as both the negative and positive electrodes and a Na-ion conducting gel polymer as the electrolyte. The as-prepared OCG with dense and porous structure ensures abundant ion-accessible active sites and short ion diffusion path. The surface oxygen functional groups within OCG are favorable for high energy storage when applied as both battery-type negative electrodes and capacitor-type positive electrodes. Benefiting from the elaborate design of electrode materials and device configuration, the QSS–NIC achieves a high energy density of 121.3 W h kg−1, high power density of 8000 W kg−1 and a long cycling life of over 2500 cycles with a capacitance retention of ~ 86.7%. This work successfully demonstrates a proof of concept of quasi-solid-state Na-ion hybrid capacitors as a high performance energy storage device based on two graphene electrodes, which narrows the performance gap between conventional electrochemical capacitors and batteries.
- Published
- 2018
37. Confined Self-Assembly in Two-Dimensional Interlayer Space: Monolayered Mesoporous Carbon Nanosheets with In-Plane Orderly Arranged Mesopores and a Highly Graphitized Framework
- Author
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Jie Wang, Kevin C.-W. Wu, Yusuke Yamauchi, Xiaogang Zhang, Bing Ding, Zhi Chang, and Yunling Xu
- Subjects
Supercapacitor ,Materials science ,Graphene ,chemistry.chemical_element ,General Chemistry ,02 engineering and technology ,General Medicine ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,law.invention ,0104 chemical sciences ,chemistry.chemical_compound ,Montmorillonite ,Chemical engineering ,chemistry ,law ,Self-assembly ,Mesoporous material ,0210 nano-technology ,Nanoscopic scale ,Carbon ,Nanosheet - Abstract
Although two-dimensional (2D) carbon materials are widely investigated, a well-defined 2D carbon nanosheet with an ordered mesostructure has rarely been realized. Monolayer-ordered mesoporous carbon nanosheets (OMCNS) were prepared through confinement assembly of resol and F127 in the interlayer of montmorillonite (MONT). The nanoscale distance of the interlayer space of MONT only allow the assembly of resol and F127 in the same plane, leading to ordered mesopores perpendicular to carbon nanosheets, and favor the formation of sp2 carbon, resulting in a high degree of graphitization. The mesopores on the carbon nanosheets provide efficient ion diffusion, and the high degree of graphitization provides a fast electron-transport route, enabling OMCNS as excellent electrode materials for electric double layer capacitors.
- Published
- 2018
38. Chemical constituents from the seeds of Capparis masaikai.
- Author
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Caicai Xi, Yunling Xu, Kang Feng, Renzhao Wu, and Shihong Luo
- Subjects
- *
SEEDS , *SUCCINIMIDES , *ESTERS , *X-rays , *ACIDS , *ETHANOLAMINES , *CATECHOL , *ADENOSINES - Abstract
A total of 21 compounds were isolated from the seeds of Capparis masaikai and identified as oxazolidine-2-thione (1), succinimide (2), catechol (3), octathiocane (4), monoethanolamine (5), 3-hydroxypropanenitrile (6), L-arabinose (7), 1,2,3-propanetriol (8), drummondol (9), spionoside B (10), adenosine (11), corchoionoside C (12), coniferin (13), syringin (14), cis-syringin (15), dihydrosyringin (16), indole-3-carboxylic acid (17), β-D-glucopyranosyl indole-3-carboxylic acid (18), 6-hydroxyindole-3-carboxylic acid β-D-glucopyranosyl ester (19), linoleis monoglyceride (20), and triolein (21). Their structures were identified based on physicochemical property and spectroscopic analysis, including MS, NMR, and single-crystal X-ray crystallographic data. Compounds 2–10 and 12–21 were isolated from C. masaikai for the first time. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
39. Heteroatom-Doped Porous Carbon Nanosheets: General Preparation and Enhanced Capacitive Properties
- Author
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Ya Wang, Xiangjun Lu, Bing Ding, Laifa Shen, Xiaogang Zhang, Jie Wang, Yunling Xu, Hui Dou, Xiaodong Hao, and Zhi Chang
- Subjects
Supercapacitor ,Chemistry ,Capacitive sensing ,Organic Chemistry ,Heteroatom ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,Catalysis ,0104 chemical sciences ,Specific surface area ,0210 nano-technology ,Porosity ,Current density ,Carbon - Abstract
High-performance electrical double-layer capacitors (EDLCs) require carbon electrode materials with high specific surface area, short ion-diffusion pathways, and outstanding electrical conductivity. Herein, a general approach combing the molten-salt method and chemical activation to prepare N-doped carbon nanosheets with high surface area (654 m2 g−1) and adjustable porous structure is presented. Owing to their structural features, the N-doped carbon nanosheets exhibited superior capacitive performance, demonstrated by a maximum capacitance of 243 F g−1 (area-normalized capacitance up to 37 μF cm−2) at a current density of 0.5 A g−1 in aqueous electrolyte, high rate capability (179 F g−1 at 20 A g−1), and excellent cycle stability. This method provides a new route to prepare porous and heteroatom-doped carbon nanosheets for high-performance EDLCs, which could also be extended to other polymer precursors and even waste biomass.
- Published
- 2016
40. Interface miscibility induced double-capillary carbon nanofibers for flexible electric double layer capacitors
- Author
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Yusuke Yamauchi, Hui Dou, Jing Tang, Jung Ho Kim, Ya Wang, Yunling Xu, Bing Ding, Xiaogang Zhang, Zhi Chang, Xiaodong Hao, and Jie Wang
- Subjects
Supercapacitor ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Capillary action ,Carbon nanofiber ,Nanotechnology ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,0104 chemical sciences ,law.invention ,Capacitor ,law ,Electrode ,Optoelectronics ,General Materials Science ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Porosity - Abstract
The preparation of free-standing electrode materials with high specific capacitance and flexibility is very important for the production of flexible electric double layer capacitors. There is a great incompatibility, however, between the flexibility and the porosity of the electrode material. In this work, by using coaxial electrospinning, we propose an interface miscibility induced approach to the design of double-capillary carbon nanofibers (DCNF) with micropores in the inner capillary and mesopores in the outer capillary. The unique structure achieves synergism between high accessibility to electrolyte, a short diffusion length for ions, high conductivity, and high flexibility. The DCNFs can be directly used as electrodes to assemble flexible supercapacitors, which show a high gravimetric capacitance of 133 F g −1 and excellent high-rate performance in ionic liquid electrolyte. The maximum energy density and power density reach 56.6 Wh kg −1 and 114 kW kg −1 , respectively. The combination of scalable coaxial electrospinning technology and supercapacitors with excellent performance may pave the way to wearable and safe electronics.
- Published
- 2016
41. A Bayesian Constancy-Enforced Non-Inferiority Design in Medical Device Trials with a Binary Endpoint
- Author
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Ram Tiwari, Yunling Xu, Nelson Lu, and Ying Yang
- Subjects
Medical device ,Computer science ,business.industry ,Bayesian probability ,Binary number ,Machine learning ,computer.software_genre ,Active control ,Test (assessment) ,Non inferiority ,Bayesian framework ,Artificial intelligence ,business ,computer - Abstract
Non-inferiority trials are commonly seen in medical device trials. However, the violation of the constancy assumption could be a serious concern. Some approaches have been proposed to address the impact of violation of the constancy assumption on the validity of a non-inferiority trial such as prevention through good trial conduct and adjustment through analysis. In this paper, we propose a new approach via adding a companion constancy test to the non-inferiority test that consequently protects the validity of a non-inferiority trial under Bayesian framework. In addition, as some clinical data from historical studies are available for the active control prior to the start of the investigational study, we consider two different methods to borrow the available information. We use a simulation study to assess the performance of the proposed approach.
- Published
- 2019
42. Anatomy and function of the vertebral column lymphatic network in mice
- Author
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Anne Eichmann, Seyoung Lee, Salli Antila, Yunling Xu, Eric Song, Kari Alitalo, Juliette Pestel, José Marques de Brito Neto, Thomas Mathivet, Harri Nurmi, Ligia Simoes Braga Boisserand, Besma Barka, Jean-Leon Thomas, Marie-Stéphane Aigrot, Luiz Henrique Medeiros Geraldo, Laurent Jacob, Nicolas Renier, Jean-Mickael Thomas, CAN-PRO - Translational Cancer Medicine Program, Faculty of Medicine, University of Helsinki, Research Programs Unit, Kari Alitalo / Principal Investigator, HUSLAB, Gestionnaire, Hal Sorbonne Université, Institut du Cerveau = Paris Brain Institute (ICM), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Sorbonne Université (SU)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Yale School of Medicine [New Haven, Connecticut] (YSM), Paris-Centre de Recherche Cardiovasculaire (PARCC - UMR-S U970), Hôpital Européen Georges Pompidou [APHP] (HEGP), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Statistique en grande dimension pour la génomique, Département PEGASE [LBBE] (PEGASE), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), [GIN] Grenoble Institut des Neurosciences (GIN), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Grenoble Alpes (UGA), Institut du Cerveau et de la Moëlle Epinière = Brain and Spine Institute (ICM), Institut National de la Santé et de la Recherche Médicale (INSERM)-CHU Pitié-Salpêtrière [AP-HP], Sorbonne Université-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Neurophysiologie Respiratoire Expérimentale et Clinique, Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Biologie des Interactions Neurones / Glie, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de la Santé et de la Recherche Médicale (INSERM), Yale University School of Medicine, Translational Cancer Biology Program [Helsinki, Finland] (Wihuri Research Institute), University of Helsinki-Biomedicum Helsinki-Wihuri Research Institute [Helsinki, Finland], Institut de la Vision, Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Pierre et Marie Curie - Paris 6 (UPMC), Angiogénèse embryonnaire et pathologique, Centre interdisciplinaire de recherche en biologie (CIRB), Labex MemoLife, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Labex MemoLife, Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière (CRICM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Hôpital Européen Georges Pompidou [APHP] (HEGP), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO), Université Paris Descartes - Paris 5 (UPD5)-Hôpital Européen Georges Pompidou [APHP] (HEGP), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpitaux Universitaires Paris Ouest - Hôpitaux Universitaires Île de France Ouest (HUPO)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre interdisciplinaire de recherche en biologie (CIRB), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Labex MemoLife, and Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de la Santé et de la Recherche Médicale (INSERM)
- Subjects
0301 basic medicine ,Male ,DECALCIFYING PROTOCOLS ,[SDV.MHEP.PHY] Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO] ,[SDV]Life Sciences [q-bio] ,FEATURES ,General Physics and Astronomy ,Fluorescence imaging ,0302 clinical medicine ,VESSELS ,VASCULATURE ,Image Processing, Computer-Assisted ,lcsh:Science ,Spinal cord injury ,ComputingMilieux_MISCELLANEOUS ,Spine regulation and structure ,Multidisciplinary ,Microscopy, Confocal ,integumentary system ,Anatomy ,Lymphangiogenesis ,medicine.anatomical_structure ,Lymphatic system ,[SDV.IMM]Life Sciences [q-bio]/Immunology ,TISSUES ,[SDV.IMM] Life Sciences [q-bio]/Immunology ,Science ,Central nervous system ,Mice, Transgenic ,General Biochemistry, Genetics and Molecular Biology ,Thoracic duct ,Article ,Thoracic Duct ,NEUROGENESIS ,03 medical and health sciences ,CEREBROSPINAL-FLUID ,medicine ,[SDV.MHEP.PHY]Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO] ,Animals ,Spinal Cord Injuries ,Lymphatic Vessels ,business.industry ,General Chemistry ,biochemical phenomena, metabolism, and nutrition ,medicine.disease ,Spinal cord ,Epidural space ,Cardiovascular biology ,Spine ,Mice, Inbred C57BL ,030104 developmental biology ,Microscopy, Fluorescence ,lcsh:Q ,Lymph Nodes ,3111 Biomedicine ,business ,030217 neurology & neurosurgery ,Vertebral column ,SYSTEM - Abstract
Cranial lymphatic vessels (LVs) are involved in the transport of fluids, macromolecules and central nervous system (CNS) immune responses. Little information about spinal LVs is available, because these delicate structures are embedded within vertebral tissues and difficult to visualize using traditional histology. Here we show an extended vertebral column LV network using three-dimensional imaging of decalcified iDISCO+-clarified spine segments. Vertebral LVs connect to peripheral sensory and sympathetic ganglia and form metameric vertebral circuits connecting to lymph nodes and the thoracic duct. They drain the epidural space and the dura mater around the spinal cord and associate with leukocytes. Vertebral LVs remodel extensively after spinal cord injury and VEGF-C-induced vertebral lymphangiogenesis exacerbates the inflammatory responses, T cell infiltration and demyelination following focal spinal cord lesion. Therefore, vertebral LVs add to skull meningeal LVs as gatekeepers of CNS immunity and may be potential targets to improve the maintenance and repair of spinal tissues., The lymphatic vasculature is essential to maintain fluid homeostasis and immune surveillance, including in the brain where lymphatic vessels were only recently identified. Here, Jacob et al. provide an anatomical map of lymphatic vessels in the vertebral column, where they find these contribute to fluid drainage and immune responses.
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- 2019
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43. SLIT2/ROBO signaling in tumor-associated microglia and macrophages drives glioblastoma immunosuppression and vascular dysmorphia.
- Author
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Geraldo, Luiz H., Yunling Xu, Jacob, Laurent, Pibouin-Fragner, Laurence, Rao, Rohit, Maissa, Nawal, Verreault, Maïté, Lemaire, Nolwenn, Knosp, Camille, Lesaffre, Corinne, Daubon, Thomas, Dejaegher, Joost, Solie, Lien, Rudewicz, Justine, Viel, Thomas, Tavitian, Bertrand, De Vleeschouwer, Steven, Sanson, Marc, Bikfalvi, Andreas, and Idbaih, Ahmed
- Subjects
- *
BRAIN tumors , *TUMOR growth , *GLIOBLASTOMA multiforme , *CELL migration , *GENE expression profiling , *MICROGLIA , *IMMUNOLOGICAL tolerance , *DISEASE progression , *NERVE tissue proteins , *XENOGRAFTS , *GROWTH factors , *ANIMAL experimentation , *CELL receptors , *GLIOMAS , *MACROPHAGES , *CELL physiology , *CELLULAR signal transduction , *GENES , *CELLS , *GENETIC techniques , *MICE - Abstract
SLIT2 is a secreted polypeptide that guides migration of cells expressing Roundabout 1 and 2 (ROBO1 and ROBO2) receptors. Herein, we investigated SLIT2/ROBO signaling effects in gliomas. In patients with glioblastoma (GBM), SLIT2 expression increased with malignant progression and correlated with poor survival and immunosuppression. Knockdown of SLIT2 in mouse glioma cells and patient-derived GBM xenografts reduced tumor growth and rendered tumors sensitive to immunotherapy. Tumor cell SLIT2 knockdown inhibited macrophage invasion and promoted a cytotoxic gene expression profile, which improved tumor vessel function and enhanced efficacy of chemotherapy and immunotherapy. Mechanistically, SLIT2 promoted microglia/macrophage chemotaxis and tumor-supportive polarization via ROBO1- and ROBO2-mediated PI3K-γ activation. Macrophage Robo1 and Robo2 deletion and systemic SLIT2 trap delivery mimicked SLIT2 knockdown effects on tumor growth and the tumor microenvironment (TME), revealing SLIT2 signaling through macrophage ROBOs as a potentially novel regulator of the GBM microenvironment and immunotherapeutic target for brain tumors. [ABSTRACT FROM AUTHOR]
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- 2021
- Full Text
- View/download PDF
44. Three-dimensional porous MXene/layered double hydroxide composite for high performance supercapacitors
- Author
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Hui Dou, Jie Wang, Ya Wang, Bing Ding, Zhi Chang, Yunling Xu, and Xiaodong Hao
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Supercapacitor ,Materials science ,Renewable Energy, Sustainability and the Environment ,Composite number ,Energy Engineering and Power Technology ,Nanotechnology ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Hydroxide ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,Porosity ,Electrical conductor ,Current density - Abstract
In this work, an exfoliated MXene (e-MXene) nanosheets/nickel-aluminum layered double hydroxide (MXene/LDH) composite as supercapacitor electrode material is fabricated by in situ growth of LDH on e-MXene substrate. The LDH platelets homogeneously grown on the surface of the e-MXene sheets construct a three-dimensional (3D) porous structure, which not only leads to high active sites exposure of LDH and facile liquid electrolyte penetration, but also alleviates the volume change of LDH during the charge/discharge process. Meanwhile, the e -MXene substrate forms a conductive network to facilitate the electron transport of active material. The optimized MXene/LDH composite exhibits a high specific capacitance of 1061 F g−1 at a current density of 1 A g−1, excellent capacitance retention of 70% after 4000 cycle tests at a current density of 4 A g−1 and a good rate capability with 556 F g−1 retention at 10 A g−1.
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- 2016
45. A Note on Good Practice of Objective Propensity Score Design for Premarket Nonrandomized Medical Device Studies with an Example
- Author
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Nelson Lu, Vandana Mukhi, Yunling Xu, Heng Li, and Lilly Q. Yue
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Statistics and Probability ,Balance assessment ,medicine.medical_specialty ,Medical device ,business.industry ,Pharmaceutical Science ,Investigational device exemption ,01 natural sciences ,Regulatory Submission ,Clinical study ,010104 statistics & probability ,03 medical and health sciences ,0302 clinical medicine ,Propensity score matching ,Econometrics ,Medicine ,Medical physics ,030212 general & internal medicine ,0101 mathematics ,business ,Good practice - Abstract
In this short note, we highlight some key elements of the process of submitting an investigational device exemption of a nonrandomized clinical study that involves the use of propensity score methodology. Focus is given to the assessment of balance for propensity score stratification.
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- 2016
46. A modified molten-salt method to prepare graphene electrode with high capacitance and low self-discharge rate
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Yunling Xu, Bing Ding, Jie Wang, Hui Dou, Laifa Shen, Ya Wang, Xiaogang Zhang, and Xiaodong Hao
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Supercapacitor ,Materials science ,Graphene ,Oxide ,Nanotechnology ,02 engineering and technology ,General Chemistry ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,General Materials Science ,Molten salt ,0210 nano-technology ,Self-discharge ,Graphene oxide paper - Abstract
Graphene is known to suffer from severe aggregation and incomplete recovery of a π–π conjugated system during the reduction process from graphene oxide. Here we report that these issues can be addressed by using a modified molten salt system. The advantages of the molten salt for reducing graphene show in three aspects: (i) prevent restacking; (ii) restore the conjugated network; (iii) serve as reaction medium for KNO 3 activation and nitrogen doping. The molten-salt method-derived graphene (MNG) displays a highly sp 2 –hybrid constitution, nitrogen doping and hierarchically porous structure. With this design, the MNG–based supercapacitor manifests outstanding specific capacitance (234 F g −1 and 130 F g −1 in 6 M KOH and EMIMBF 4 electrolyte, respectively), high power density, combined with excellent cycling stability and low self-discharge rate. The facile and scalable features of this strategy will be helpful for the rational design of functionalized graphene-based materials for diverse applications.
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- 2016
47. Nanospace-confined synthesis of oriented porous carbon nanosheets for high-performance electrical double layer capacitors
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Bing Ding, Jie Wang, Hui Dou, Zhi Chang, Xiaodong Hao, Yunling Xu, and Ya Wang
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Materials science ,Nanostructure ,Renewable Energy, Sustainability and the Environment ,Carbonization ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,General Chemistry ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,0104 chemical sciences ,law.invention ,Capacitor ,chemistry ,law ,Specific surface area ,General Materials Science ,0210 nano-technology ,Current density ,Carbon - Abstract
Two-dimensional (2D) carbon nanosheets have emerged as an attractive candidate for electrical double layer capacitors (EDLCs) due to their large specific surface area, good electrical conductivity and high charge mobility. However, the easy aggregation nature of nanosheets hinders rapid transport of electrolyte ions, reducing the ion-accessible area and restricting the ion transportation. Herein, we propose a template strategy for preparing three-dimensional (3D) porous carbon nanosheets (PCNs) with an oriented and interconnected nanostructure. Zinc layered hydroxide nitrate is used as a layered template and provides a nanospace to confine the carbonization process of the organic carbon precursor (gallic acid). The unique nanostructure and large surface area of chemically activated PCNs (aPCNs) significantly shorten the ion transport length in low dimensions and improve the electrolyte wettability and ion accessible surface area for charge storage. The aPCNs exhibit excellent performance as demonstrated by their large specific capacitance (327 F g−1 at a current density of 0.5 A g−1), superior rate capability (retaining 60.2% at 20 A g−1) and stable cyclability. In particular, the assembled symmetric device based on aPCNs delivers an energy density as high as 10.2 W h kg−1 at a power density of 301 W kg−1.
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- 2016
48. General Strategy to Fabricate Ternary Metal Nitride/Carbon Nanofibers for Supercapacitors
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Laifa Shen, Hui Dou, Yunling Xu, Xiaogang Zhang, Bing Ding, and Jie Wang
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Supercapacitor ,Materials science ,Carbon nanofiber ,chemistry.chemical_element ,Nanotechnology ,Nitride ,Titanium nitride ,Catalysis ,Electrospinning ,chemistry.chemical_compound ,chemistry ,Nanofiber ,Electrochemistry ,Ternary operation ,Carbon - Abstract
In this work, ternary metal nitrides are proposed as novel electrode materials for supercapacitors. We selectively fabricate ternary vanadium titanium nitride/carbon (VTiN/C) nanofibers through a facile electrospinning strategy and investigate their electrochemical performance for the first time. The obtained well-interconnected VTiN/C nanofibers with VTiN nanoparticles embedded into carbon ensure rapid electron/ion transfer and offer a highly ion-accessible surface. Appealingly, the VTiN-4/C nanofibers exhibit a greatly improved performance, with a high specific capacitance (430.7 F g−1, 0.5 A g−1) and a good rate capability. Furthermore, the performance of the VTiN/C nanofibers is found to be controllable by adjusting the V/Ti atomic ratio. The encouraging electrochemical performance suggests that ternary VTiN could be a promising electrode material for supercapacitors.
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- 2015
49. Crumpled Nitrogen-Doped Graphene for Supercapacitors with High Gravimetric and Volumetric Performances
- Author
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Jie Wang, Bing Ding, Laifa Shen, Xiaogang Zhang, Yunling Xu, and Hui Dou
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Supercapacitor ,Materials science ,Graphene ,Ionic transfer ,Nanotechnology ,Electrolyte ,Electrochemistry ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Electrode ,Ionic liquid ,Gravimetric analysis ,General Materials Science - Abstract
Graphene is considered a promising electrochemical capacitors electrode material due to its high surface area and high electrical conductivity. However, restacking interactions between graphene nanosheets significantly decrease the ion-accessible surface area and impede electronic and ionic transfer. This would, in turn, severely hinder the realization of high energy density. Herein, we report a strategy for preparation of few-layer graphene material with abundant crumples and high-level nitrogen doping. The two-dimensional graphene nanosheets (CNG) feature high ion-available surface area, excellent electronic and ion transfer properties, and high packing density, permitting the CNG electrode to exhibit excellent electrochemical performance. In ionic liquid electrolyte, the CNG electrode exhibits gravimetric and volumetric capacitances of 128 F g(-1) and 98 F cm(-3), respectively, achieving gravimetric and volumetric energy densities of 56 Wh kg(-1) and 43 Wh L(-1). The preparation strategy described here provides a new approach for developing a graphene-based supercapacitor with high gravimetric and volumetric energy densities.
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- 2015
50. Synergistically improved electrochemical performance and its practical application of graphene oxide stabilized nano Ag2S by one-pot homogeneous precipitation
- Author
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Yunling Xu, Wenli Yao, Shina Yan, Qi Zhao, Lei Hu, Zhengquan Yan, Xinming Xu, and Kangwei Gongsun
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Materials science ,Composite number ,Oxide ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Redox ,law.invention ,Metal ,chemistry.chemical_compound ,law ,Nano ,Graphene ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Surfaces, Coatings and Films ,chemistry ,Chemical engineering ,visual_art ,visual_art.visual_art_medium ,Cyclic voltammetry ,0210 nano-technology - Abstract
Based on the high specific area and superior electrochemical property of graphene oxide and excellent electro-catalytic performance of Ag2S, graphene oxide stabilized nano Ag2S composite (GO-Ag2S) was proposed and constructed in this work by one-pot homogeneous precipitation. It was expected GO-Ag2S could possess special stability, dispersion and electrochemical activity, which were estimated by SEM, TEM, EDS, XRD, FT-IR, cyclic voltammetry and electrochemical impedance spectra. It was noted that there was a synergistically improved electrochemical performance between Ag2S and GO in as-prepared GO-Ag2S owing to their strong interactions. Especially, it exhibited an exclusively electrochemical response to heavy metal Hg2+ with high sensitivity once modified onto glassy carbon electrode (GCE). Under the optimized conditions, a wide liner range of 0.0–290.0 × 10−10 mol/L and a low detection limit of 8.63 × 10−12 mol/L for Hg2+ could be reached. Once applied for sensing Hg2+ in really environmental water samples and fruit juice samples, the recovery was between 95.5% and 105.7%. Mercury amalgam formed onto the surface of nano Ag2S was accordingly proposed for GO-Ag2S to recognize Hg2+ after the electro-catalytic redox of Hg2+.
- Published
- 2020
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