1,357,145 research outputs found
Concentration in Knowledge Output: A case of Economics Journals
No full textThis paper assesses the degree of author concentration in seven economics journals, which were published in India during 1990-2002. To measure the degree of author concentration, Lotka's Law was used. Moreover, we also make an exploratory analysis of the geographic, economics subfield and institutional concentration in 704 economics journals. An important finding of this paper is that specialized journals in the sample report the highest degree of author concentration. This result is quite similar to the findings by Cox and Chung (1991). Furthermore, there are several instances showing that the journals lean towards certain norms; this may affect the flow of innovative ideas into economics. We conclude that a knowledge activity, involving the high degree of concentration and a biased publication process, may affect the flow of new ideas into the discipline.Concentration, Lotka's Law
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
만성뇌졸중 동물모델에서의 유전자변형 중간엽줄기세포의 치료 효과
No full textStroke is the major cause of death and disability worldwide. Despite numerous clinical and preclinical studies in the stroke arena, therapeutic approaches to treat chronic stroke are not properly established. We previously reported that in the acute phase of stroke, mesenchymal stem cells overexpressing Neurogenin 1 (MSCs/Ngn1) showed enhanced therapeutic efficacy compared to naïve mesenchymal stem cells (MSCs). In this study, we found that MSCs/Ngn1 were unable to exert similar beneficial effects when transplanted in the chronic phase. Thus, we genetically modified MSCs/Ngn1 cells using adenovirus encoding hepatocyte growth factor, HGF (MSCs/Ngn1+HGF) and transplanted in the chronic stroke brain. Transplantation of MSCs/Ngn1+HGF cells in chronic stroke significantly improved the behavioral deficits and brain tissue integrity when assessed with sensory-motor function tests and MRI, respectively. Immunohistochemical analyses indicated that the transplantation of MSCs/Ngn1+HGF cells rejuvenated the microenvironment of the damaged brain tissue. To explore the mechanism of post-stroke neurogenesis, we utilized Nestin-GFP mice, a transgenic mouse model where neural stem/progenitor cells can be detected as GFP. Here, we report that in normal adult Nestin-GFP mice, GFP transgene labeled mostly GFAP+ type B neural stem cells in SVZ and NG2 proteoglycan expressing progenitors in striatum and cortex. In a chronic stroke model of Nestin-GFP mice, mesenchymal stem cells co-expressing Ngn1 and HGF enhanced the proliferation and neuronal differentiation of these Nestin- GFP/NG2+ cells in the injured brain. This result was also observed in the in- vitro culture of cortex derived Nestin-GFP/NG2+ cells. Furthermore, this enhanced neurogenesis was associated with subsequent improvement in behavior and brain tissue integrity. Our genetically modified MSCs, MSCs/Ngn1+HGF cells satisfied the STEP3 guidelines suggested for preclinical studies by FDA and NIH (2014), might provide a potential therapeutic strategy for the treatment of chronic stroke.뇌졸중은 전세계 사망원인 2위인 질환으로 일단 발생하면 사망 또는심각한 장애를 유발할 수 있다. 많은 뇌졸증 분야에서 다양한 임상 및 전임상 연구에도 불구하고, 혈전용해제/기술외에 뇌졸중의 치료제/기술은 아직 확립되지 않았다. 중간엽줄기세포 (mesenchymal stem cells, MSCs)가 급성기 뇌졸중 동물모델에서의 효능이 있으며, 신경분화촉진인자인 Neurogenin1을 과발현시킨 중간엽줄기세포(MSCs/ Ngn1)는 그 효능이 증진된다는 전임상연구가 보고된 바 있다. 하지만 만성뇌졸증 단계에서는 MSCs/ Ngn1의 효능은 미미한 것으로 나타났다. 따라서, 본연구에서는 아데노바이러스를 사용하여 MSCs/Ngn1세포에 간세포성장인자 (hepatocyte growth factor, HGF)를 발현시 중간엽줄기세포(MSCs/Ngn1+HGF)의 효능을 만성뇌졸중 동물모델에서 조사하였다. 만성뇌졸중은 뇌동맥결찰은 자기공명영상(magnetic resonance imaging)으로 뇌졸중이 유도됨을 확인한 후 1개월이 지난 동물을 사용하였다. MSCs/Ngn1+HGF 세포를 만성뇌졸중 동물모델의 뇌에 이식하였다. MRI로 분석하였을 때, 뇌조직이 조금 더 보전되어 있음을 밝혔고, 이는 운동기능의 개선과 비례함을 발견하였다. 또한 면역조직 화학염색을 통해 MSCs/Ngn1+HGF 세포의 이식이 이미 손상되어 있던 뇌조직의 미세환경을 젊어지게한다는 것을 밝혔다. 그 작용기전을 조사하기 위하여 신경줄기세포에서만 형광단백질(green fluorescence protein, GFP)를 발현하도록 고안된 Nestin-GFP 형질전환마우스를 활용하였다. 신경줄기세포가 있다고 알려진 subventricular zone (SVZ)에서 신경줄기세포의 마커인 glial fibro (GFAP)와 Nestin 프로모터에 의해 조절되는 GFP가 동시에 발현됨을 확인함으로써, 뇌내 줄기세포의 추적연구에 Nestin-GFP 마우스의 활용가능성을 확인하였다. 흥미롭게도 GFP를 발현하는 세포가 SVZ가 아닌 뇌선조체(striatum)와 대뇌피질(cortex)에서 NG2를 발현하는 전구세포(progenitor)임을 발견하였다. 만성뇌졸중 모델에서, MSCs/Ngn1+HGF 세포는 GFP와 NG2를 발현하는 전구세포의 증식을 촉진하였으며, 이 전구세포세가 신경세포로 분화되도록 유도하였다. MSCs/Ngn1+HGF 세포의 배양액(분비물질)은 일차배양된 줄기세포에 처리했을 때 신경세포로의 분화를 촉진하였다. 이 결과는 MSCs/Ngn1+HGF이 분비하는 물질이 SVZ가 아닌 뇌조직내에 산재해있는 NG2를 발현하는 전구세포의 증식과 신경분화를 촉진함으로써 행동개선과 조직보전의 효과를 유도함을 의미한다. 나아가 본 연구결과는 MSCs/Ngn1+HGF 세포는 FDA와 NIH가 제시한 STEP3 가이드라인의 전임상연구 (2014)에 부합하는 치료전략이 될 수 있음을 시사한다.I. INTRODUCTION 1
II. MATERIALS AND METHODS 8
1. Study approval 8
2. Animals 8
3. Tamoxifen injection 8
4. Tissue preparation 9
5. Assessment of Cre induction efficiency 9
6. Neurosphere Culture 10
7. Mesenchymal stem cell culture and genetic modification 10
8. Surface antigen analysis 12
9. Induction of multi-lineage Differentiation 13
10. Senescence associated β-galactosidase assay 14
11. Transgene stability under growth-restrictive conditions 15
12. Real-time PCR analysis 15
13. Western blotting 16
14. Immunocytochemistry 17
15. In-vitro Angiogenesis assay 18
16. In-vitro NSC Proliferation assay 18
17. In-vitro Neuronal differentiation assay 19
18. Animal models and cell transplantation 19
19. Behavior assessment 21
20. Measurement of infarct volume (MRI) 24
21. Histological analysis 26
22. Immunohistochemistry 27
23. Statistical analysis 28
III. RESULTS 29
Part A. Chronic stroke animal models and therapeutic effects of MSC/Ngn1 cells in chronic stroke 29
1. Characterization of chronic stroke animal models 29
2. Therapeutic effects of MSC/Ngn1 cells in chronic stroke 40
Part B. Adenoviral mediated therapeutic genes transfer in MSCs 42
1. MSC transduction with adenoviral vector expressing GFP 42
2. Transgene expression and growth kinetics of Ad-GFP-transduced MSCs 42
3. Cell surface marker expression and multi-lineage differentiation 45
4. Long-term transgene expression under growth-restricted conditions 48
5. Generation of MSC and MSC/Ngn1 cells overexpressing HGF 48
6. Cell surface marker expression and multilineage differentiation of Adeno- HGF transduced MSC and MSC/Ngn1 cells 51
Part C. Therapeutic effects of HGF overexpressing MSC/Ngn1 cells in chronic stroke 54
1. Improved functional recovery and tissue integrity with MSCs/Ngn1+HGF 54
2. Augmentation of neuro-regenerative mechanisms by MSC/Ngn1+HGF 57
3. Neuronal differentiation of MSC/Ngn1+HGF cells in chronic stroke 63
Part D. Chronic stroke model of Nestin-GFP transgenic mice as a tool for studying non-canonical neurogenesis 65
1. Characterization of Nestin-GFP cells in adult mouse brain 65
2. Characterization of Cortical Nestin-GFP cells in-vitro 69
3. Enhanced proliferation and neuronal differentiation of adult brain parenchymal Nestin-GFP progenitors by MSC/Ngn1+HGF cells in chronic stroke model of Nestin-GFP mice 71
Part E: NG2CreERTM::RosaFloxedTdTomato double transgenic reporter mice as a Model System to study parenchymal neurogenesis from NG2 cells in chronic stroke 77
1. Characteristics of NG2 positive progenitor cells in the parenchyma / non-canonical niche of the normal brain 77
2. In-vivo differentiation of NG2-TdTomato cells in adult mouse brain parenchyma 83
3. Characterization of NG2-TdTomato cells in vitro 85
Part F: Role of conditioned media from HGF overexpressing MSCs on in-vitro model of
Neurogenesis and angiogenesis 89
1. Effects of Conditioned media from HGF overexpressing MSCs on proliferation and neuronal differentiation of NG2 cells 89
2. Effects of conditioned media from HGF overexpressing MSCs on in-vitro angiogenesis of bEND.3 cells 93
IV. DISCUSSION & CONCLUSION 95
V. REFERENCES 103Docto
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
question-guide_SOM-WHE-18-0023 – Supplemental material for ‘Menstrual blood is bad and should be cleaned’: A qualitative case study on traditional menstrual practices and contextual factors in the rural communities of far-western Nepal
No full textSupplemental material, question-guide_SOM-WHE-18-0023 for ‘Menstrual blood is bad and should be cleaned’: A qualitative case study on traditional menstrual practices and contextual factors in the rural communities of far-western Nepal by Subash Thapa, Shivani Bhattarai and Arja R Aro in SAGE Open Medicine</p
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
The Thursday Murder Club: Launching a megabrand author - a publishing case study
No full textIn 2020, the Christmas book charts in the UK made headlines: Barack Obama’s eagerly awaited autobiography, The Promised Land, was beaten to the top spot by The Thursday Murder Club by Richard Osman, a debut cosy crime novel set in a retirement village. Not only did Osman’s book beat the former US president’s expected bestseller, it also broke records, becoming the fastest-selling debut crime novel of all time. Although Osman has a certain level of fame in the UK from his TV appearances on shows such as Pointless, his celebrity status does not entirely explain the novel’s huge sales. This article tracks the acquisition, publication, and promotion journey of The Thursday Murder Club in order to understand the industry and cultural context of its success and to interrogate the role of celebrity in the creation of author brands. The findings suggest that the unexpected scale of the success of the book owed to a number of factors, including in-depth editing by the novel’s agent, editor, and author to tighten up the plot, an extensive and strategic promotional campaign, the pandemic (which drove interest in the book’s genre and themes), and the quality of the writing. We find that the book’s success was accentuated by Osman’s celebrity status rather than being entirely reliant on it. This research adds to the growing scholarship on celebrity authorship by means of an in-depth case study and provides insight into the processes behind publishing a ‘celebrity’ book and launching a megabrand author
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