128,163 research outputs found
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
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
Pseudoreceptors for Hepatitis B Virus Infection
No full textB型肝炎病毒如何進入細胞至今仍具爭議。由於B型肝炎病毒只可感染人類以及某些靈長類，因此缺乏方便操作的實驗動物模型，B型肝炎病毒在動物體內的感染及致病基轉的研究也因此受限，另外，至今仍然沒有細胞株可提供B型肝炎病毒完成完整的生活史（從感染到複製）。在過去的研究， 關於B型肝炎病毒進入細胞之後的複製機轉研究的很清楚，但對於B型肝炎病毒藉由何種受體以及如何附著在肝細胞上，則所知甚少。B型肝炎病毒顆粒的外套膜蛋白，決定病毒與人類肝細胞結合的重要角色，很多研究已猜測多種細胞表面蛋白可能是B型肝炎病毒的受體，但是這些結果卻無法互相佐證，某些研究顯示，B型肝炎病毒顆粒上的preS1區域可能在與人類肝細胞結合上扮演重要的角色。此論文中，我們構築表現在細胞膜上的單鏈抗體以作為B型肝炎的偽受體，這個偽受體包含MA18/7（抗preS1區域的單株抗體）的單鏈抗體變異區（scFv），以及LDLR, EGFR, ICAM1的穿膜區域（transmembrane domain）和細胞質區域（cytoplasmic domain）。人類肝癌細胞（HepG2）在表現偽受體後確實可以與B型肝炎病毒結合，利用共軛焦顯微鏡﹙confocal﹚，可觀察到被吞噬的B型肝炎病毒顆粒與endosomal標記蛋白（運鐵蛋白）在細胞內位置是重疊的，但被吞噬的B型肝炎病毒顆粒無法成功地進入溶酶體（lysosome），因此無法確定B型肝炎病毒顆粒是否脫去外套膜成功地脫離endosome。如果成功，可利用此策略研究病毒與細胞之間的交互作用，將其轉殖在小鼠上也可以作為B型肝炎病毒感染的小動物模型，用以開發新疫苗及研究致病機轉的工具。
本論文根據已發表的核酸序列，設計寡聚核苷酸並利用疊合聚合酶連鎖反應得到MA18/7的基因，同時我們利用合成preS1胜肽鏈免疫老鼠，同時生產抗preS1區域的細胞融合瘤，並將這些單株抗體以酵素免疫分析法及西方點墨法作定性及測試其抗原決定位。Hepatitis B virus entry is controversial. Insight into the fundamentals of the HBV life cycle has been impeded by severe experimental obstacles posed by (a) the narrow host range of the virus (resulting in the absence of convenient animal models of infection and disease), and (b) the lack of cell lines that support productive HBV replication. Although much information about the molecular biology of HBV has been gained in the past decade, little is known about the mechanism of attachment and penetration of the HBV particle into human hepatocytes. The HBV envelope proteins are important for the interaction between HBV particle and the hepatocyte plasma membrane. A number of cellular protein have been suggested to be HBV receptors, but studies on the HBV receptor during the last decade produced controversial and confusing results. Some observations suggested that the preS1 domain is probably the most important attachment site of HBV to human hepatocytes. In this study, we proposed to engineer a membrane-anchored single chain antibody as an artificial receptor for HBV infection. We generated pseudoreceptors by fusing the single chain variable region (scFv) of MA18/7, a monoclonal antibody (mAb) against HBV preS1 domain, to transmembrane and cytoplasm domains of the low-density lipoprotein receptor (LDLR), epidermal growth factor receptor (EGFR), or intracellular adhesion molecule-1 (ICAM-1). HepG2 cells expressed the pseudoreceptors were shown to bind HBV particles. Using confocal microscope we visualized the colocalization of HBV particles with the endosomal marker transferrin. Internalized HBV was not efficiently moved to lysosomes. Therefore, it is still unknown internalized HBV can uncoat its envelope and escape the endosomes. This approach, if successful, may be useful for studying virus reception and for the development of safer vaccines against viral pathogens of animals and humans.
According to published sequences, we designed oligonucleotide and employed overlapping PCR to generate variable region of MA18/7. At the same time, we produced anti-preS1 hybridoma by synthetic preS1 peptide. We characterize the monoclonal anti-preS1 antibodies by ELISA and immunoblotting, and briefly epitope mapping.Contents
Chinese Abstract………………………………………………………………..1
English Abstract………………………………………………………………...2
1. Introduction…………………………………………………………………4
1.1 HBV overview……………………………………………………………...4
1.2 Hepadnaviruses……………………………………………………………..4
1.3 HBV structure and HBV surface protein…………………………………...6
1.4 HBV cellular binding protein………………………………………………7
1.4.1 Small HBsAg-binding domain………………………………………….8
1.4.2 PreS2 binding domain…………………………………………………..8
1.4.3 PreS1-binding domain…………………………………………………10
1.5 HBV infection models….............................................................................12
1.6 Pseudoreceptor applications………………………………………………13
1.7 Summary of the major routes of endocytosis used by viruses…………….13
1.8 Strategy……………………………………………………………………16
2. Material and methods……………………………………………………...18
2.1 Plasmids construction……………………………………………………..18
2.2 Transfection of transgenes………………………………………………...18
2.3 Immunoblotting…………………………………………………………...18
2.3.1 Immunoblotting of pseudoreceptors chimeric proteins………………..18
2.3.2 Immunoblotting of HBV particles……………………………………..19
2.4 Flow cytometer analysis…………………………………………………..20
2.5 Retrovirus-mediated expression…………………………………………..20
2.5.1 Transfection…………………………………………………………....20
2.5.2 Viral infection………………………………………………………….20
2.6 Cell sorting………………………………………………………………...21
2.7 Isolate HBV virions……………………………………………………….21
2.8 Electron microscopy (EM)………………………………………………..22
2.9 Confocal microscopy……………………………………………………...22
2.9.1 HBV binding ability…………………………………………………...22
2.9.2 Immmunofluorescence of HBV and human transferrin internalization………………………………………………………….23
2.9.3 HBV and lysotracker localization……………………………………...23
2.10 PreS1 peptide conjugated to BSA or OVA……………………………….24
2.11 Produce anti-preS1 hybridoma…………………………………………...25
2.11.1 Immunization of mice with OVA-preS1……………………………….25
2.11.2 Hybridoma fusion……………………………………………………...25
2.11.3 Screening primary hybridomas………………………………………...26
2.11.4 Limiting dilution……………………………………………………….26
2.12 Ascites generation………………………………………………………..26
2.13 Mouse IgG1 antibody purification by protein A…………………………27
2.14 Q-PCR……………………………………………………………………27
2.14.1 Non-hybridization probes……………………………………………...27
2.14.2 Hybridization probes…………………………………………………..28
2.15 Enzyme-linked immunosorbent assay(ELISA)…………………………..28
2.15.1 HBsAg detection……………………………………………………….28
2.15.2 Anti-preS1 hybridoma screening ELISA……………………………...29
2.16 HBV infection……………………………………………………………30
3. Results……………………………………………………………………..31
3.1 Generation of plasmids for surface expression of pseudoreceptors………31
3.2 Chemeric protein are expressed on the cell surface……………………….31
3.3 HBV purification………………………….………………………………32
3.4 HBV electron microscopy………………………………………………...33
3.5 Pseudoreceptors can bind HBV particles…………………………………34
3.6 HBV particles colocalized with endosomal marker………………………35
3.7 HBV particles little or no colocalized with lysosome…………………….36
3.8 Characteristics of anti-preS1 hybridoma………………………………….36
3.9 HBV replicated slowly in HepG2-MA18/7-LDLR……………………….38
4. Discussion…………………………………………………………………40
4.1 Comparison of HBV particles from HBV transgenic mice and chronic infected humans…………………………………………………………...40
4.2 Expression and binding ability of pseudorecepotors……………………...40
4.3 HBV entry into HepG2 cells through pseudoreceptors instead of transferring………………………………………………………………...41
4.4 HBV particles didn’t efficiently colocalize with lysosome……………….41
4.5 Applications of anti-preS1 hybridoma…………………………………….42
4.6 HBV infection……………………………………………………………..43
4.7 Workable applications of this study………………………………………44
5. Figures……………………………………………………………………..45
Figure 1. Strategy of the experiment………………………………………….45
Figure 2. Diagram of pseudoreceptor transgenes……………………………..46
Figure 3. Expression of pseudoreceptors in HepG2 human hepatoma cells…47
Figure 4. HBV purification-batch I…………………………………………...48
Figure 5. HBV purification batch II…………………………………………..49
Figure 6. Electron micrographs……………………………………………….50
Figure 7. Electron micrographs……………………………………………….51
Figure 8. MA18/7-eB7 pseudoreceptors bind to HBV particles…….………..52
Figure 9. MA18/7-LDLR pseudoreceptors bind to HBV particles…………...53
Figure 10. MA18/7-ICAM1 pseudoreceptors bind to HBV particles…….......54
Figure 11. MA18/7-EGFR pseudoreceptors bind to HBV particles…………..55
Figure 12. Anti-phOx-eB7 doesn’t bind to HBV at a MOI of 10000…………56
Figure 13. HBV didn’t entry into HepG2-MA18/7-LDLR at 4℃……………57
Figure 14. HBV colocalized with endosomal marker at 37℃ for 30min……..58
Figure 15. HBV colocalized with endosomal marker at 37℃ for 60 min…….59
Figure 16. HBV colocalized with endosomal marker at 37℃ for 120min……60
Figure 17. HBV didn’t entry into HepG2-MA18/7-eB7 at 4℃………………61
Figure 18. Few HBV particles entry into HepG2-MA18/7-eB7at 37℃ for 60 min...................................................................................................62
Figure 19. Few HBV particles colocalized with endosomal marker in HepG2-MA18/7-eB7 at 37℃ for 120min……………..………….63
Figure20. HBV particles don’t colocalize with LysoTracker after infection at 37℃...................................................................................................64
Figure 21. HBV particles don’t colocalize with LysoTracker after infection at 37℃, 60min…………………………………………………….......65
Figure 22. Few HBV particles colocalized with LysoTracker after infection at 37℃ for 60min……………………………………………………..66
Figure 23. Few HBV particles colocalized with LysoTracker after infection at 37℃, 2 hour………………………………………………………...67
Figure 24. Nucleotide sequence and derived amino acid sequence for the VH domain of the mAb MA18/7……………………………………......68
Figure 25. Nucleotide sequence and derived amino acid sequence for the VL domain of the mAb MA18/7………….…………………………….69
Figure 26. SMCC-conjugated BSA and OVA………………………………...70
Figure 27. Anti-preS1 polyclonal antibody titer………………………………71
Figure 28. 5 hours of post-fusion……………………………………………...72
Figure 29. Anti-preS1 antibodies recognize HBV virions…………………….73
Figure 30. Surface single chain antibody MA18/7 doesn’t compete with anti-preS1 antibody…………………………………………………74
Figure 31. 6F1E8D8 recognizes the first half of the preS1 peptides and 3C6B2 recognize the second half………………………………………..….75
Figure 32. Surface single chain antibody MA18/7 doesn’t compete with anti-preS1 antibody…………………………………………………76
Figure 33. The epitope of 3C6B2 clone of anti-preS1 antibody is different from MA18/7……………………………………………………………..77
Figure 34. 3C6 clone is considered to be usable for western blotting………...78
Figure 35. HBsAg in culture medium after HBV infection…………………...79
Figure 36. HBV viral DNA in culture medium after HBV infection…………80
6. Reference…………………………………………………………………..8
Metadata summary of <i>Giardia</i> isolates collected and sequencing statistics collected by Tsui et al.
No full textMetadata summary of Giardia isolates collected and sequencing statistics collected by Tsui et al.</p
Pragmatic Case Studies as a Source of Unity in Applied Psychology
No full textTo unify or not to unify applied psychology: that is the question. In this article we review pendulum swings in the historical efforts to answer this question—from a comprehensive, positivist, “top-down,” deductive yes between the 1930s and the early 60s, to a postmodern no since then. A rationale and proposal for a limited, “bottom-up,” inductive yes in applied psychology is then presented, employing a case-based paradigm that integrates both positivist and postmodern themes and components. This paradigm is labeled “pragmatic psychology” and, its specific use of case studies, the “Pragmatic Case Study Method” (“PCS Method”). We call for the creation of peer-reviewed journal-databases of pragmatic case studies as a foundational source of unifying applied knowledge in our discipline. As one example, the potential of the PCS Method for unifying different angles of theoretical regard is illustrated in an area of applied psychology, psychotherapy, via the case of Mrs. B. The article then turns to the broader historical and epistemological arguments for the unifying nature of the PCS Method in both applied and basic psychology.Peer reviewe
Volatility Dynamics in Foreign Exchange Rates: Further Evidence from the Malaysian Ringgit and Singapore Dollar
No full textSingapore dollar are analyzed in this paper. Our approach can simultaneously capture the empirical regularities of persistent and asymmetric effects in volatility and timevarying correlations of financial time series. Consistent with the results of Tse and Tsui (1997), there is only some weak support for asymmetric volatility in the case of the Malaysian ringgit when the two currencies are measured against the US dollar. However, there is strong evidence that depreciation shocks have a greater impact on future volatility levels compared with appreciation shocks of the same magnitude when both currencies measured against the yen. Moreover, evidence of time-varying correlation is highly significant when both currencies are measured against the yen. Regardless of the choice of the numeraire currency and the volatility models, shocks to exchange rate volatility are found to be significantly persistent.Constant correlations; Exchange rate volatility; Fractional integration; Long memory; Bivariate asymmetric GARCH; Varying correlations
Dr. Edwin Wright Collection: Author Unknown
No full textNotes - The author relates several short stories about his neighbours including Alex McDonell, homesteading and life around Meanook and Athabasca (1 page
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
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
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