1,720,953 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Cellular mechanosensitivity in vitro: cell-ECM, cell-cell, and cell-material interactions
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Previous issue date: 2015-05-13Embargo set by: Seth Robbins for item 89520
Lift date: 2017-09-29T21:03:28Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 89520
Lift date: 2017-09-29T21:08:35Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 89520 on 2017-09-30T09:15:30Z.In recent years it has become increasingly evident that physical cues like mechanical micro-environment and geometry, in addition to bio-chemical factors, plays an important role in regulating cell functionalities. Cancer cells also respond to 2D and 3D matrix stiffness in a complex manner using a coordinated, hierarchical mechano-chemical system composed of adhesion receptors and associated signal transduction membrane proteins, the cytoskeletal architecture, and molecular motors. Mechanosensitivity of different cancer cells in vitro are investigated primarily with immortalized human cancer cell lines or murine derived primary cells, not with primary human cancer cells. Hence, little is known about the mechanosensitivity of primary human colon cancer cells in vitro.
In the first part of this dissertation, an optimized protocol is described that demonstrates the isolation of primary human colon cells from healthy and cancerous surgical human tissue samples. Isolated colon cells are then successfully cultured on soft (2 kPa stiffness) and stiff (10 kPa stiffness) polyacrylamide (PA) hydrogels and rigid polystyrene (~3.6 GPa stiffness) substrates functionalized by an extracellular matrix (fibronectin in this case). Fluorescent microbeads are embedded in soft gels near the cell culture surface, and traction assay is performed to assess cellular contractile stresses. Our findings suggest that both the healthy and tumor cells are mechanosensitive. Their average spread area increased with increase in substrate stiffness, and they displayed actin stress fibers and elongated focal adhesions on rigid polystyrene substrates only. Traction cytometry results on soft gels are the first experimental evidence that primary colon tumor cells can generate augmented traction compared to their healthy counterparts. In addition, the contrast between traction patterns and metastatic staging raises the possibility of introducing a potent biophysical marker of cancer metastasis with other molecular biomarkers.
In the second part, we study the role of cell-cell adhesions on the substrate elasticity mediated metastasis-like phenotype (MLP) of human colon carcinoma (HCT-8) cells. HCT-8 cells on PA gels is an attractive in vitro biomaterial platform as they exhibit a dissociative, metastasis-like phenotype (MLP) when cultured on extra-cellular matrix (ECM) coated gels with appropriate mechanical stiffness (20–47 kPa), but not on very stiff (3.6 GPa) polystyrene substrates. We ask the question whether similar morphological transition occurs on cell-cell adhesion molecule, i.e., E-cadherin coated PA gels and if so, how the actin cytoskeleton and focal adhesions compare with ECM mediated response on gels. Experimental results suggest that MLP of HCT-8 cells on PA gels is independent of cell to gel adhesion in 2D in vitro culture.
Finally, we challenge the classical readouts of cellular mechanosensing by examining cell response on soft biological gel, namely, collagen. Our results show that different types of fibroblasts can exhibit spread morphology, well defined actin stress fibers, and larger focal adhesions even on very soft collagen gels (modulus in hundreds of Pascals) as if they are on hard glass substrate (modulus in GPa, several orders of magnitude higher). Strikingly, we show, for the first time, that augmented cell spreading and other hard substrate cytoskeleton architecture on soft collagen gels are not correlated with cell proliferation pattern unlike PA gels and do not require nuclear transcriptional regulator YAP (Yes associated protein) localization in cell nucleus. HCT-8 cell clusters also show augmented spreading/wetting on soft collagen gels unlike PA gels and eventually form confluent monolayer as on rigid glass substrates and MLP is completely inhibited on soft collagen gels. Overall, these results in the third part suggest that cell-material interaction (soft collagen gels in this case) can induce cellular phenotype and cytoskeleton organization in a remarkably distinct manner compared to a classical synthetic polyacrylamide (PA) hydrogel cell culture model and may contribute in designing new functional biomaterials.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2017-08-01The student, Muhammad Yakut Ali, accepted the attached license on 2015-05-06 at 19:14.The student, Muhammad Yakut Ali, submitted this Dissertation for approval on 2015-05-06 at 19:15.This Dissertation was approved for publication on 2015-05-13 at 13:58.DSpace SAF Submission Ingestion Package generated from Vireo submission #8214 on 2015-09-29 at 15:04:5
Variations on the Author
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Experimental Investigation of the Effect of Copper Nanowires On Heat Transfer and Pressure Drop For A Single Phase Microchannel Heat Sink
No full textThis thesis experimentally investigates the heat transfer and pressure drop characteristics of a shallow rectangular single phase microchannel heat sink with hydraulic diameter of 0.672 mm and whose bottom wall is coated with Cu nanowires (CuNWs) of 200 nm in diameter and 0.050 mm in length. CuNWs are grown on Cu heat sink by electroplating technique which is inexpensive and readily scalable. The heat transfer and pressure drop results of CuNWs enhanced heat sink are compared with that of bare copper heat sink using deionized (DI) water as working fluid at Reynolds Number (Re) ranging from 106-636. The experimental results indicate an enhancement in Nusselt Number (Nu) at all Re with a maximum enhancement of 24% at Re = 106. Whereas an increase in pressure drop is observed in all test cases due to enhanced roughness.
The enhanced thermal performance is possibly attributed to two properties of Cu nanowire arrays- improvement in surface wettability characteristics and enhanced heat transfer area. The surface morphology of the heat sink has also been studied before and after heat transfer experiments through SEM to assess any effect of fluid flow. The SEM results demonstrate no notable change in surface morphology within the Re range in which experiments have been conducted. The presented innovative scheme has the capability to dissipate higher heat flux per unit area and can be extended to two phase microchannel heat sink
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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