1,721,062 research outputs found
In vitro hBM-MSCs characterization and differentiation on the scaffold for bone regenerative medicine
Full text linkNew methods have been developed to achieve tissue regeneration of complex bone defects and restore the healing process, which is impaired by several factors; in this contest bone tissue engineering (BTE) is an alternative to autologous gold-standard treatment. BTE combines biocompatible scaffolds with morphogenic signals and stem cells, to create a biomimetic microenvironment that provides mechanical and chemical cues.
In this project, we studied all key elements of BTE and evaluated Mesenchymal stem cells (MSC) with xenograft-derived bone scaffold (SmartBone® SBN) and rhBMP-2 as growth factor. MSCs are an attractive source of stem cells because of their ability to undergo self-renewal, multi-lineage differentiation (including into osteoblast lineage) and paracrine actions. Here, we reported our experience in MSCs expansion protocols and proposed human Platelet-Rich Plasma (PRP) as a substitute for Fetal Bovine Serum (FBS) in media supplementation. After MSCs isolation from patients bone marrow, we expanded the cells in media supplemented with FBS or PRP, obtained from a venous blood sample of the same patients. Our final outcome indicated that PRP is a good cell culture supplement, since it did not impact MSCs marker expression and differentiation potential.
In the second part of the project, we seeded hBM-MSC on xenograft-derived bone scaffold and cultured them in osteogenic and MSC expansion media to investigate the effects of the composition of support on cell metabolic activity and osteogenic differentiation. The scaffold retains biological properties and resembles the human bone structure. We demonstrated its biocompatibility supporting both BM-MSCs proliferation and differentiation. Moreover, new collagen deposition was revealed in both analyzed conditions, suggesting a good osteoconductivity of the scaffold.
Finally, we aimed to modify the scaffold by the addition of rhBMP-2 to improve its osteogenic abilities and enhance new bone formation. Future experiments will assess the impact of BMP2 modification on cellular differentiation
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
Septic shock, acute renal and liver failure following unsafe abortion using bitter leaves and wandering jew in northern Uganda: A case series
No full textUnsafe abortion is a major problem in Uganda, being one of the leading causes of maternal morbidity and mortality. Abortions are performed mostly under unsafe conditions, by people without medical training. In rural areas in northern Uganda, women often resort to traditional providers, who use local herbs as abortion remedies, usually with adverse outcomes. Little is known about the biological properties of these herbs and their toxicity profile. Here, we present the case series of two women, of 31 and 24 years of age, who underwent unsafe abortion for unintended pregnancy by using herbal medicines, that is, Commelina Africana (wandering jew) and Vernonia amygdalina (bitter leaf), respectively. While the first case resulted in uterine necrosis and pelvic peritonitis, which required multiple surgical interventions and the use of reserve antibiotics, the second case resulted in liver and renal failure that led to the death of the patient. This case series describes the unusual severe toxicity of two herbal medicines that are frequently used to induce abortion in northern Uganda. It highlights possible associations of Commelina Africana (wandering jew) with uterine necrosis complicated by sepsis, and of Vernonia amygdalina (bitter leaf) with acute liver and renal failure
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
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