1,720,954 research outputs found
Impact of cell cycle dependent endocytosis of DNA-wrapped single-walled carbon nanotubes (DNA-SWCNTs) on the fate of neural progenitors
No full textNanomaterials have been employed as imaging agents and drug delivery vehicles for disease therapy across the medical field. Carbon nanotubes in particular are of the appropriate size and can be modified with functional groups to allow transport through the blood brain barrier (BBB) and aid in delivery of therapeutics to the central nervous system (CNS). In this study, the entry and lasting effects of nano-molar concentrations of (GT)20 DNA-wrapped single walled carbon nanotubes (SWCNT, roughly 1 nm dia, 100+ nm length) on C17.2 neural progenitor cells (NPCs) was examined. Though commonly used concentrations, often in the micro-molar range, have yielded evidence of cytotoxicity and reorganization of cellular sub structure, the use of nanomaterials have been shown to have promise in therapeutics in vitro and in vivo when size, concentration and functionalization are considered and optimized. Low picomolar concentrations of DNA-SWCNTs exposure have shown to augment cell division and differentiation of NPCs. While this discovery opens a gateway for nanomaterials-based therapies for neurogenesis, the mechanisms of cellular entry, long-term residence, and their effect on cell structure and fate are not well understood.Given that cellular fate process such as cell division and differentiation were affected by the presence of the nanomaterials, an investigation into the role of the cell cycle was initiated to understand the implications of these materials. Common drugs (lovastatin, thymidine and nocodazole) were used as cell cycle arrest agents to synchronize neural stem cells (NSCs) in phases (early G1, late G1/S and G2/M respectively) as discerned by flow cytometry, at rates (80%, 85% and 89% respectively) that rival previously documented levels of synchrony for stem cells. This ultimately induced phase-dependent normalized cellular organization on which further correlations could be assessed. The internalized SWCNTs were then visualized for localization and correlation with intracellular components using hyperspectral imaging via confocal micro-Raman spectroscopy. Imaging SWCNT uptake post-synchrony showed that cultures of majority late G1/S cells led to a 40% decrease in uptake, while cultures consisting primarily of early G1 and G2/M cells led to 40% and 390% increases in uptake, respectively. This suggests that the late G1 and early S phases are selective to uptake of materials, and G2/M phase is an avid acceptor of materials as it has a four-fold higher yield of internalized nanotubes per cell on average, when compared to control cells. This proves the dependency of uptake on the mitotic phase of the cell cycle.Subsequently, three main endocytic mechanisms were surveyed for their contributions to NT uptake and the dependency of endocytosis on the cell cycle: receptor mediated endocytosis (RME), macropinocytosis (MP), clathrin-independent endocytosis (CIE). Known inhibitors of endocytosis (hypertonic sucrose, amiloride and filipin) were used to gain individual control over established endocytic delivery machineries (of receptor mediated endocytosis, macro-pinocytosis and clathrin-independent endocytosis respectively) which resulted in an 87%, 61% and 67% decrease in uptake of SWNTs respectively, in comparison to the control. With reductions across the board in all mechanisms post-inhibition, the results showed that all three mechanisms contribute in some capacity to the uptake of DNA-wrapped SWCNT in C17.2 NPCs, with strong suggestions towards the substitution of one or more endocytic mechanisms in the absence of others.Finally, the connection between the endocytosis of SWCNTs and the induction of early differentiation in NPCs was examined. Pathway bioinformatics was performed using databases along with literature study to determine a functional gene set of key markers and pathways involved in the instigation of differentiation. Protein expression studies revealed that Notch1 and numb proteins are key players in C17.2 NSC differentiation. Similarly, doublecortin (DCX), NeuroD1 were determined to play varying roles in differentiation. MAP2 and GFAP expression gave insight into post treatment neuron and astrocyte development. These studies will lead to further insights into chronology of altered cellular dynamics and molecular-level investigation of the effect of SWCNTs on NPCs
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
The impact of furniture color on consumer purchasing decisions
No full textColor plays a massive role in maximizing success, majorly influencing consumer
perceptions. As a result, understanding the impact of color is essential for anticipating and
comprehending how consumers would perceive the chosen colors. This study investigates the
complex relationship between color and consumer preferences in the context of outdoor
furniture, with the goal of understanding the distinct ways in which color impacts perceived
product attributes and purchasing decisions. The goal of this research is to contribute to both
the academic knowledge pertaining to design and the strategic use of color in outdoor furniture
in the retail environment. With the utilization of comprehensive research techniques, it
explores the substantial impact of furniture color on consumer purchasing decisions through a
quantitative survey method.M. S
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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