1,721,242 research outputs found
Development of a medical instrument to induce and control hydrogel polymerization in-situ
No full textBackground - Nucleus pulposus degeneration is a very common musculo-skeletal pathology, which is in part responsible for low back pain, a pandemic medical problem. Artificial hydrogels are being investigated by research group around the world for the purpose of replacing the damaged tissue and thus contributing to a healing solution for low back pain. In collaboration between the LTC and the LBO, a composite reinforced hydrogel has been developed with mechanical and swelling characteristics well suited for potentially replacing the nucleus pulposus. This hydrogel contains the photoinitiator Irgacure 2959 (maximum absorption at 280 nm). It is thus polymerizable through UV exposition. In previous work, the UV illumination was obtained using an EXFO Omnicure S2000 UV light source. Hydrogel cylinders (10mm in diameter and 5 mm in thickness) were obtained with 145 mW/cm2 for 30 minutes at room temperature in vitro. The goal of this project is to develop a technological solution to polymerize homogeneously and completely the hydrogel in situ, i.e. inside the body in the annulus pulposus. Information on the polymerization status in-situ (i.e the degree of polymerization, homogeneity) would be a very useful indicator for the purpose of ensuring proper polymerization and thus the mechanical properties sought. The “probe” device is restricted to less than 6 mm in diameter in order to allow access to the nucleus pulposus by the surgeon. Proposition –We propose the following planning: 1. Defining the technical requirement of the project (illumination homogeneity, exposure time, illumination wavelength, hydrogel volume). 2. Propose different options to bring the hydrogel in-situ, to polymerize it and measure its degree of polymerization in-situ. 3. Select best option based on technical, surgical and economical aspects. 4. Realize a prototype. 5. Test it in a laboratory environment. 6. Test it in an ex vivo animal model. References 1. Borges A. Composite hydrogels for the replacement of the nucleus pulposus. EPFL thesis #4817.LBOLTCLAP
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
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
Tomographic volumetric bioprinting of 3D pancreatic cancer models
No full textAbstract
Pancreatic ductal adenocarcinoma (PDAC) is the most frequent type of pancreatic cancer, one of the leading causes of cancer-related deaths worldwide. PDAC is marked by a dense, fibrous tumor microenvironment, in which stromal fibroblasts surround the cancerous ductal epithelial cells. The cross-talk between pancreatic cells and the surrounding fibroblasts leads to inflammation and stiffening of the surrounding tissue, which is believed to hinder anti-cancer drugs’ uptake and effectiveness. In vitro, fully human models of the pancreatic cancer microenvironment are needed to foster the development of new, more effective therapies; but it is still challenging to make these models anatomically and functionally relevant. Here, we use tomographic volumetric bioprinting, a novel method to fabricate cell-laden multi-mm viable constructs within less than a minute, to produce anatomically relevant fibroblast-laden gelatine methacrylate-based pancreatic duct models, including a duct and an acinus. We then seeded human pancreatic ductal epithelial (HPDE) cells, wild type or cancerous, into these models and evaluated the progression of the constructs for several days after printing. We show that the 3D pancreatic duct models remain viable for up to 14 days after bioprinting. We used immunofluorescence to evaluate the surrounding fibroblasts' activation by quantifying the relative expressions of alpha smooth muscle actin (SMA) vs. actin in the fibroblasts. SMA is known to be overespressed in inflammated tumor-associated fibroblasts, and to lead to tissue stiffening. We show that SMA expression is significantly higher in fibroblasts co-cultured with cancerous than with wild-type HPDE cells, that this expression increases with time, and that it is higher in fibroblasts that lay closer to HPDE cells than in those deeper into the model. These models could potentially be used in drug development or to shed light on the early progression of the disease.
Contents
This repository contains the raw data, materials list, protocols, and code necessary to reproduce the work in the namesake preprint
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
