71 research outputs found

    Investigation of interactions between poly-l-lysine-coated boron nitride nanotubes and C2C12 cells: up-take, cytocompatibility, and differentiation

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    Boron nitride nanotubes (BNNTs) have generated considerable interest within the scientific community by virtue of their unique physical properties, which can be exploited in the biomedical field. In the present in vitro study, we investigated the interactions of poly-l-lysine-coated BNNTs with C2C12 cells, as a model of muscle cells, in terms of cytocompatibility and BNNT internalization. The latter was performed using both confocal and transmission electron microscopy. Finally, we investigated myoblast differentiation in the presence of BNNTs, evaluating the protein synthesis of differentiating cells, myotube formation, and expression of some constitutive myoblastic markers, such as MyoD and Cx43, by reverse transcription – polymerase chain reaction and Western blot analysis. We demonstrated that BNNTs are highly internalized by C2C12 cells, with neither adversely affecting C2C12 myoblast viability nor significantly interfering with myotube formation

    Autophagy-related protein LC3 and Beclin-1 in the first trimester of pregnancy

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    Autophagy is a degradation process that acts in response to environmental stressors. Recently, autophagy has been detected in normal term, preeclamptic and intrauterine growth-restricted placentas. The object of this work was to investigate the presence of autophagy in first trimester voluntary interruption of pregnancy placental villi by the expression of autophagy-related proteins, light chain 3 (LC3), and Beclin-1. In first trimester placental villi laser scanning confocal microscopy (LSCM) analysis revealed LC3 and Beclin-1 immunoreactivity prevalently located in villous cytotrophoblasts. Using LSCM, LC3, and Beclin-1 were localized to the cytoplasm of the trophoblast layer in human full-term placentas. Beclin-1 expression and LC3 activation were confirmed by western blotting. These data emphasize that autophagy activation is different among cytotrophoblasts and syncytiotrophoblasts depending on the gestational age and thus we speculate that autophagy might play a prosurvival role throughout human pregnancy

    The use of indigenous knowledge in development: problems and challenges

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    The use of indigenous knowledge has been seen by many as an alternative way of promoting development in poor rural communities in many parts of the world. By reviewing much of the recent work on indigenous knowledge, the paper suggests that a number of problems and tensions has resulted in indigenous knowledge not being as useful as hoped for or supposed. These include problems emanating from a focus on the (arte)factual; binary tensions between western science and indigenous knowledge systems; the problem of differentiation and power relations; the romanticization of indigenous knowledge; and the all too frequent decontextualization of indigenous knowledge

    Growing bone tissue-engineered niches with graded osteogenicity: an in vitro method for biomimetic construct assembly

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    The traditional bone tissue-engineering approach exploits mesenchymal stem cells ( MSCs) to be seeded once only on three-dimensional (3D) scaffolds, hence, differentiated for a certain period of time and resulting in a homogeneous osteoblast population at the endpoint. However, after achieving terminal osteodifferentiation, cell viability is usually markedly compromised. On the other hand, naturally occurring osteogenesis results from the coexistence of MSC progenies at distinct differentiative stages in the same microenvironment. This diversiïŹcation also enables long-term viability of the mature tissue. We report an easy and tunable in vitro method to engineer simple osteogenic cell niches in a biomimetic fashion. The niches were grown via periodic reseeding of undifferentiated MSCs on MSC/scaffold constructs, the latter undergoing osteogenic commitment. Timefractioning of the seeded cell number during differentiation time of the constructs allowed graded osteogenic cell populations to be grown together on the same scaffolds (i.e., not only terminally differentiated osteoblasts). In such cell-dynamic systems, the overall differentiative stage of the constructs could also be tuned by varying the cell density seeded at each inoculation. In this way, we generated two different biomimetic niche models able to host good reservoirs of preosteoblasts and other osteoprogenitors after 21 culture days. At that time, the niche type resulting in 40.8% of immature osteogenic progenies and only 59.2% of mature osteoblasts showed a calcium content comparable to the constructs obtained with the traditional culture method (i.e., 100.03 – 29.30 vs. 78.51 – 28.50 pg/cell, respectively; p = not signiïŹcant), the latter colonized only by fully differentiated osteoblasts showing exhausted viability. This assembly method for tissue-engineered constructs enabled a set of important parameters, such as viability, colonization, and osteogenic yield of the MSCs to be balanced on 3D scaffolds, thus achieving biomimetic in vitro models with graded osteogenicity, which are more complex and reliable than those currently used by tissue engineers

    The Right Place at the Right Time: Creative Spaces in Libraries

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    Purpose This essay explores the recent trend in libraries: that of the establishment of spaces specifically set aside for creative work. The rise of these dedicated creative spaces is owed to a confluence of factors that happen to be finding their expression together in recent years. This essay examines the history of these spaces and explores the factors that gave rise to them and will fuel them moving forward. Design/Methodology/Approach A viewpoint piece, this essay combines historical research and historical/comparative analyses to examine the ways by which libraries have supported creative work in the past and how they may continue to do so into the 21st century. Findings The key threads brought together include a societal recognition of the value of creativity and related skills and attributes; the philosophies, values, and missions of libraries in both their longstanding forms and in recent evolutions; the rise of participatory culture as a result of inexpensive technologies; improved means to build community and share results of efforts; and library experience and historical practice in matters related to creativity. The chapter concludes with advice for those interested in the establishment of such spaces, grounding those reflections in the author’s experiences in developing a new creative space at Virginia Commonwealth University. Originality/value While a number of pieces have been written that discuss the practicalities of developing certain kinds of creative spaces, very little has been written that situates these spaces in larger social and library professional contexts; this essay begins to fill that gap

    2-Methoxy aniline grafted poly(maleic anhydride-alt-butyl vinyl ether) hemiester: A new biocompatible polymeric free radical scavenger

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    Free radical scavenger biocompatible polymers are being used increasingly in biomedical applications due to their antioxidant activity. In this study, the biocompatible polymer poly(maleic anhydride-alt-butyl vinyl ether) 5% grafted with monomethoxy poly(ethylene glycol) 2000 MW (PEG) and 95% grafted with 2-methoxyethanol (VAM41-PEG) was modified by inserting a conductive moiety represented by 2-methoxy aniline (mAn) in order to attribute to the polymer radical scavenger properties. Different reaction schemes were tested in order to maximize the reaction yield. The increase in the scavenger activity of the modified polymer was demonstrated by means of the DPPH(center dot) radical assay. Cytotoxicity tests, performed on the mAn modified polymeric matrix, were carried out using the mouse embryo fibroblast cell line balb/3T3 Clone A31. Results have shown that the introduction of mAn into VAM41-PEG polymeric structure does not alter its cytocompatibility

    Social website technologies and their impact on society

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    Introduction Web applications have dominated the concerns of most people because they take a lot of their time. Among the most prominent of these concerns is the social networking that is available through social network applications on the internet. Social websites have impacted heavily on social and national identity as well as on the social bonding within the community. Why does the social network matter? Human nature is generally social and people like to live in a community rather than in isolation. Social networks play this role electronically by connecting people as a community regardless of the distance. Evidence shows that these applications are attractive and have a strong influence in various areas. The deductive approach has been used in this chapter which analysed texts relevant to the subject of the study. Descriptive documentary in the collection of information from sources and references associated with the subject of the study described and employed an approach to describe the phenomenon as list of the diagnosis and detection aspects to determine the relationship between elements with a prospect for the future and predict scientific outcomes

    Porous scaffolds of polycaprolactone reinforced with in situ generated hydroxyapatite for bone tissue engineering

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    Polycaprolactone/hydroxyapatite (PCL/HA) composites were prepared by in situ generation of HA in the polymer solution starting from the precursors calcium nitrate tetrahydrate and ammonium dihydrogen phosphate via sol–gel process. Highly interconnected porosity was achieved by means of the salt-leaching technique using a mixture of sodium chloride and sodium bicarbonate as porogens. Structure and morphology of the PCL/HA composites were investigated by scanning electron microscopy, and mechanical properties were determined by means of tensile and compression tests. The possibility to employ the developed composites as scaffolds for bone tissue regeneration was assessed by cytotoxicity test of the PCL/HA composites extracts and cell adhesion and pro- liferation in vitro studies
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