7 results
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2. Bioorthogonal click chemistry for fluorescence imaging of choline phospholipids in plants
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Kathrin Schrick, Janet M. Paper, and Thiya Mukherjee
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0106 biological sciences ,0301 basic medicine ,Cell signaling ,Arabidopsis thaliana ,Membrane lipids ,Phospholipid ,Fluorescence labeling ,Plant Science ,lcsh:Plant culture ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Phosphatidylcholine ,Genetics ,Propargylcholine ,Choline ,lcsh:SB1-1110 ,lcsh:QH301-705.5 ,Phospholipids ,Alexa Fluor ,Click chemistry ,fungi ,Methodology ,food and beverages ,Plant cell ,ESI-MS/MS ,030104 developmental biology ,Membrane ,lcsh:Biology (General) ,chemistry ,Biochemistry ,lipids (amino acids, peptides, and proteins) ,010606 plant biology & botany ,Biotechnology - Abstract
Background Phospholipids are important structural and signaling molecules in plant membranes. Some fluorescent dyes can stain general lipids of membranes, but labeling and visualization of specific lipid classes have yet to be developed for most components of the membrane. New techniques for visualizing membrane lipids are needed to further delineate their dynamic structural and signaling roles in plant cells. In this study we examined whether propargylcholine, a bioortholog of choline, can be used to label the major membrane lipid, phosphatidylcholine, and other choline phospholipids in plants. We established that propargylcholine is readily taken up by roots, and that its incorporation is not detrimental to plant growth. After plant tissue is harvested and fixed, a click-chemistry reaction covalently links the alkyne group of propargylcholine to a fluorescently-tagged azide, resulting in specific labeling of choline phospholipids. Results Uptake of propargylcholine, followed by click chemistry with fluorescein or Alexa Fluor 594 azide was used to visualize choline phospholipids in cells of root, leaf, stem, silique and seed tissues from Arabidopsis thaliana. Co-localization with various subcellular markers indicated coinciding fluorescent signals in cell membranes, such as the tonoplast and the ER. Among different cell types in the leaf epidermis, guard cells displayed strong labeling. Mass spectrometry-based lipidomic analysis of the various plant tissues revealed that incorporation of propargylcholine was strongest in roots with approximately 50% of total choline phospholipids being labeled, but it was also incorporated in the other tissues including seeds. Phospholipid profiling confirmed that, in each tissue analyzed, incorporation of the bioortholog had little impact on the pool of choline plus choline-like phospholipids or other lipid species. Conclusion We developed and validated a click-chemistry based method for fluorescence imaging of choline phospholipids using a bioortholog of choline, propargylcholine, in various cell-types and tissues from Arabidopsis. This click-chemistry method provides a direct way to metabolically tag and visualize specific lipid molecules in plant cells. This work paves the way for future studies addressing in situ localization of specific lipids in plants. Electronic supplementary material The online version of this article (10.1186/s13007-018-0299-2) contains supplementary material, which is available to authorized users.
- Published
- 2018
3. Demystifying Grounded Theory for Business Research.
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O’Reilly, Kelley, Paper, David, and Marx, Sherry
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GROUNDED theory ,SOCIAL science methodology ,QUANTITATIVE research ,METHODOLOGY ,COMPARATIVE method - Abstract
The grounded theory method (GT) remains elusive and misunderstood by many—even those who advocate its use. In practice, many research studies cite the use of GT but merely apply certain a la carte aspects or jargon of the method while not actually incorporating the fundamental principles of the methodology. Consequently, the purpose of this article is fourfold: (a) to demystify the key tenets of GT, (b) to discuss the problematic impacts of adopting an a la carte approach to GT, (c) to draw attention to GT as a rigorous method for business research, and (d) to advocate for the increased use of GT by more researchers where appropriate. Throughout the article, the authors use the example of a recently completed GT study by the lead author to highlight the multiple dimensions of GT and how they all work together. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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4. Optimization of a magnetic bead-based assay (MAGPIX®-Luminex) for immune surveillance of exposure to malaria using multiple Plasmodium antigens and sera from different endemic settings
- Author
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Aissata Basse, Inès Vigan-Womas, Alioune Dieye, Cheikh Loucoubar, Babacar Mbengue, Marie Louise Varela, Ronald Perraut, Aissatou Touré, Institut Pasteur de Dakar, Réseau International des Instituts Pasteur (RIIP), Institut Pasteur de Madagascar, Département Parasites et Insectes vecteurs - Department of Parasites and Insect Vectors, Institut Pasteur [Paris], This study was supported by grants from Institut Pasteur Fondation, from Rotary International, ACIP (Institut Pasteur, N°25_2012) and EDCTP—European & Developing Countries Clinical Trials Partnership., We thank Dr Odile Mercereau-Puijalon and Dr Shirley Longacre for constant support and providing antigens, we are grateful to Dr Shirley Longacre for revising this paper. We thank Drs Marc Jouan and Jérôme Salomon from Division International (Institut Pasteur, Paris) for their help to initiate this work in the very early steps. We are grateful to the villagers of Dielmo and Ndiop for their active participation and continuing collaboration in the project and Pr Bacary Diatta for help providing hospital samples., and Institut Pasteur [Paris] (IP)
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0301 basic medicine ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,030231 tropical medicine ,Plasmodium falciparum ,Protozoan Proteins ,Antigens, Protozoan ,Plasmodium malariae ,Biology ,lcsh:Infectious and parasitic diseases ,Serology ,03 medical and health sciences ,0302 clinical medicine ,Antigen ,parasitic diseases ,medicine ,lcsh:RC109-216 ,Multiplex ,Malaria, Falciparum ,IgG response ,Immunoassay ,medicine.diagnostic_test ,Immunomagnetic Separation ,Magnetic beads assay ,Methodology ,medicine.disease ,biology.organism_classification ,3. Good health ,Malaria ,030104 developmental biology ,Infectious Diseases ,Immunology ,biology.protein ,[SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie ,Parasitology ,Antibody ,Biomarkers - Abstract
International audience; Background: Serological markers are potentially useful tools for monitoring the progress of malaria control programs , but a better understanding of antibody response dynamics is necessary. The use of a magnetic bead-based immunoassay (MBA) is advantageous compared to ELISA, due to its multiplexing capacity, but limited information is available on the standardization and validation of this assay. Methods: Several parameters for multiplex testing of antibodies to Plasmodium antigens were analysed using a set of 4 antigens and 98 sera from Senegalese rural asymptomatic and urban symptomatic individuals. The 4 antigens included Plasmodium falciparum CSP and PfAMA1 peptides, recombinant P. falciparum MSP4p20 and a Plasmodium malariae CSP (PmCSP) peptide. Comparisons with ELISA were done using MSP4p20 and whole schizont extract (SE) antigens.Results: The use of fewer beads (1000 beads per well instead of 2000) and 5 µg of antigen per 10 6 bead were validated as lower amounts. The use of a carrier protein (BSA) was shown to be critical when using peptides and the effect of a 24 h delayed measures was evaluated (5-25% signal decrease). Analysis of Ab responses showed almost equally high levels and prevalence in all transmission settings. Clear distinctions between rural and urban malaria were noted using PmCSP and SE antigens.Conclusions: This study underlines the importance of further optimization of the MBA technique and highlights the interest of using multistage/multispecies antigens for surveillance of malaria in endemic settings.
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- 2018
5. Economics: Between Prediction and Criticism
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Gilboa, Itzhak, Postlewaite, Andrew, Samuelson, Larry, Schmeidler, David, Haldemann, Antoine, Tel Aviv University [Tel Aviv], University of Pennsylvania [Philadelphia], Department of Economics, Yale University [New Haven], and HEC Paris Research Paper Series
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Economic Modeling ,Models ,JEL: B - History of Economic Thought, Methodology, and Heterodox Approaches/B.B4 - Economic Methodology/B.B4.B41 - Economic Methodology ,jel:B40 ,jel:B41 ,Methodology ,[SHS.GESTION]Humanities and Social Sciences/Business administration ,JEL: B - History of Economic Thought, Methodology, and Heterodox Approaches/B.B4 - Economic Methodology/B.B4.B40 - General ,[SHS.GESTION] Humanities and Social Sciences/Business administration ,Methodology, Models, Economic modeling - Abstract
We suggest that one way in which economic analysis is useful is by offering a critique of reasoning. According to this view, economic theory may be useful not only by providing predictions, but also by pointing out weaknesses of arguments. It is argued that, when a theory requires a non-trivial act of interpretation, it's roles in producing predictions and offering critiques vary in a substantial way. We offer a formal model i which these different roles can be captured.
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- 2016
6. Improving study design for antidepressant effectiveness assessment
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Naudet, Florian, Millet, Bruno, Reymann, Jean-Michel, Falissard, Bruno, Troubles du comportement alimentaire de l'adolescent (UMR_S 669), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris-Sud - Paris 11 (UP11), Centre d'Investigation Clinique [Rennes] (CIC), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Hôpital Pontchaillou-Institut National de la Santé et de la Recherche Médicale (INSERM), Comportement et noyaux gris centraux = Behavior and Basal Ganglia [Rennes], Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université européenne de Bretagne - European University of Brittany (UEB)-CHU Pontchaillou [Rennes]-Institut des Neurosciences Cliniques de Rennes (INCR), Service de Psychiatrie, Centre Hospitalier Guillaume Régnier, Service de Pharmacologie [Rennes], CHU Pontchaillou [Rennes], This paper was supported by the Institut National de la Santé et de la Recherche Médicale (INSERM)., Le Corre, Morgane, Université Paris-Sud - Paris 11 (UP11)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Rennes (UR)-Hôpital Pontchaillou-Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-CHU Pontchaillou [Rennes]-Institut des Neurosciences Cliniques de Rennes (INCR), Troubles du comportement alimentaire de l'adolescent ( UMR_S 669 ), Université Paris Descartes - Paris 5 ( UPD5 ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Université Paris-Sud - Paris 11 ( UP11 ), Centre d'Investigation Clinique [Rennes] ( CIC ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Hôpital Pontchaillou-Institut National de la Santé et de la Recherche Médicale ( INSERM ), Comportement et noyaux gris centraux [Rennes], Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Université européenne de Bretagne ( UEB ) -CHU Pontchaillou [Rennes]-Institut des Neurosciences Cliniques de Rennes (INCR), Service de Pharmacologie, and Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-CHU Pontchaillou [Rennes]-Institut des Neurosciences Cliniques de Rennes = Institute of Clinical Neurosciences of Rennes (INCR)
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Depressive Disorder, Major ,clinical trials ,[SDV.SP.MED] Life Sciences [q-bio]/Pharmaceutical sciences/Medication ,Psychometrics ,[ SDV.MHEP.PSM ] Life Sciences [q-bio]/Human health and pathology/Psychiatrics and mental health ,[ SDV.SP.MED ] Life Sciences [q-bio]/Pharmaceutical sciences/Medication ,[SDV.MHEP.PSM] Life Sciences [q-bio]/Human health and pathology/Psychiatrics and mental health ,Reproducibility of Results ,effectiveness ,methodology ,Original Articles ,Personality Assessment ,Antidepressive Agents ,Observational Studies as Topic ,Double-Blind Method ,[SDV.SP.MED]Life Sciences [q-bio]/Pharmaceutical sciences/Medication ,Research Design ,Surveys and Questionnaires ,antidepressants ,[SDV.MHEP.PSM]Life Sciences [q-bio]/Human health and pathology/Psychiatrics and mental health ,Outcome Assessment, Health Care ,depression ,Humans ,Randomized Controlled Trials as Topic - Abstract
Antidepressants effectiveness in major depressive disorder (MDD) is still questioned because the extrapolation of randomized controlled trial (RCT) results to “real life” settings is problematic. The application of the RCT paradigm in a disorder of this type, where global care plays a central role, raises questions regarding the internal and external validity of this type of study. Outcome measurement, attrition rates, the ability of the double‐blind design to control for expectations, placebo response, the representativeness of trial participants and publication bias are major methodological pitfalls. This review discusses these issues. It is illustrated using original data and proposes some alternatives for assessing antidepressant effectiveness via different approaches. Some are easy to implement, such as ecological measures, qualitative approaches, improvement of analytical strategy and improvement of blinding procedures. Some are sophisticated, involving temporary deception to deal with the confounding effect of expectations, and they raise ethical issues. Others resort to external validity, this being the case in observational studies. But all are necessary to explore antidepressant effectiveness. Copyright © 2013 John Wiley & Sons, Ltd.
- Published
- 2013
7. A New Methodology for the History of Economic Thought
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Igersheim, Herrade, Le Chapelain, Charlotte, Centre d'EPistémologie et d'ERgologie Comparatives (CEPERC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Bureau d'Économie Théorique et Appliquée (BETA), Université de Lorraine (UL)-Université de Strasbourg (UNISTRA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Université de Strasbourg (UNISTRA)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Centre d'EPistémologie et d'ERgologie Comparatives - UMR 7304 (CEPERC), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Universitat Autònoma de Barcelona (UAB), and Herrade Igersheim's contribution to this paper is partially supported by the Spanish Ministry of Education and Science through grant SEJ2005-01481/ECON and FEDER.
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Wirtschaftswissenschaft ,Volkswirtschaftstheorie ,Economics ,historical analysis ,Interdisziplinarität ,theoretical economics ,Forschungsarten der Sozialforschung ,interdisciplinarity ,Basic Research, General Concepts and History of Economics ,Wissenschaftsgeschichte ,basic research ,ddc:330 ,thinking ,Social sciences, sociology, anthropology ,ComputingMilieux_MISCELLANEOUS ,Sozialwissenschaften, Soziologie ,cliometrics ,economic theory ,Wirtschaft ,methodology ,Methodologie ,history of economic thought ,[SHS.ECO]Humanities and Social Sciences/Economics and Finance ,development of methods ,Denken ,ökonomische Theorie ,history of science ,Allgemeines, spezielle Theorien und Schulen, Methoden, Entwicklung und Geschichte der Wirtschaftswissenschaften ,Research Design ,Methodenentwicklung ,ddc:300 ,historische Analyse ,Grundlagenforschung - Abstract
Der Artikel unternimmt zu beweisen wie eine historische Vorgehensweise dazu beitragen kann verschiedene Probleme der modernen Wirtschaftstheorie besser zu verstehen. Erstens erläutern die Verfasser ihre 'Forschungsmethodologie', um die Relevanz der historischen Analyse in den Wirtschaftswissenschaften widerzuspiegeln. Die Verfasser betonen deren interdisziplinäre Vorgehensweise, da sie die Moral- und politische Philosophie, die Dogmengeschichte, die Wirtschaftstheorie sowie die modernen analytischen Instrumente einschließt. Zweitens präsentieren die Verfasser zwei Beispiele von vollendeten oder laufenden Arbeiten, die auf ihrer Methodologie beruhen. The article aims to stress that historical approach can contribute to address issues faced by modern economic theory. So as to show the relevance of historical analysis in economics, the author's first state the 'methodology' they use in their researches. The author's emphasize their interdisciplinary feature since it involves moral and political philosophy, history of economic thought, economic theory and modern analytical tools. Second, they suggest two examples of works, finished or current, which are based on their methodology.
- Published
- 2006
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