1,720,961 research outputs found
Stability andin vivosafety of gold, titanium nitride and parylene C coatings on NdFeB magnets implanted in muscles towards a new generation of myokinetic prosthetic limbs
No full textRare earth magnets are the elective choice when high magnetic field density is required and they are particularly intriguing for inclusion in implantable devices. A safe implantation of NdFeB magnets in muscles would enable the control of limb prostheses using a myokinetic interfacei.e., direct control of artificial limb movements by means of magnetic tracking of residual muscle contractions. However, myokinetic prosthesis control is prevented by NdFeB magnets poor biocompatibility, at present. Here we investigated three biocompatible materials as NdFeB magnet coating candidates, namely gold, titanium nitride and parylene C, which have not been analyzed in a systematic way for this purpose, so far.In vitrotesting in a tissue-mimicking environment and upon contact with C2C12 myoblasts enabled assessment of the superiority of parylene C coated magnets in terms of corrosion prevention and lack of cytotoxicity. In addition, parylene C coated magnets implanted in rabbit muscles for 28 days confirmed, both locally and systemically, their biocompatibility, with a lack of irritation and toxicity associated with the implant. These findings pave the way towards the development of implantable devices based on permanent magnets and of a new generation of limb prostheses
ASI-Biomission VITA Inc. 51/52 NANOROS experiment: Skeletal muscle cell protection against oxidative stress with cerium oxide nanoparticles in space IAC-18-A2.7.9
No full textWith low gravity conditions and high energy radiations, space environment exerts deleterious effects on the astronauts' musculoskeletal system, inducing/accelerating loss of skeletal muscle mass and force that are typical of aging or certain pathological conditions on Earth. In astronauts, these effects are partially reversible upon return on Earth, yet they hinder long-term permanence in space and interplanetary exploration. Oxidative stress is among the causes of the observed effects, and its onset both on Earth and in space is related to the unbalanced production/removal of highly reactive species (such as hydroxyl radical, superoxide and singlet oxygen, collectively termed as reactive oxygen species- ROS). These species are typically scavenged by endogenous antioxidant defenses (provided for instance by superoxide dismutase and catalase), in synergy with dietary intakes of natural antioxidants (like vitamins and polyphenols). Traditional antioxidants require constant supply due to their short biological activity, whereas novel materials such as cerium oxide nanoparticles (nanoceria, NC) exhibit a self-regenerative antioxidant property mimicking superoxide dismutase/catalase activity that was demonstrated in a number of cellular models and even in some disease animal models. Selected by the Agenzia Spaziale Italiana for implementation on board the International Space Station (ISS) with increment 51/52, our experiment entitled “Nanotechnology Solutions against Oxidative Stress in Muscle Tissue during Long-Term Microgravity Exposure†(NANOROS) aimed at assessing the protective role of NC as antioxidant agents on differentiating H9c2 myoblasts in space. Preliminary on-ground simulations of the whole experimental timeline (performed in hardware qualified to flight) enabled the identification of suitable cell density (30,000 cells/cm2), NC size (30 nm on average) and coating (with fetal bovine serum) to obtain high RNA concentrations (~100 ng/ul) for transcriptional analyses. The minimum concentration of NC (100 Âμg/ml) suitable to oxidative stress alleviation was also identified by administering increasing concentrations of NC (0-200 Âμg/ml) to differentiating cells, and then by providing oxidative insult with 1 mM H2O2. The amount of ROS generated by this insult was assessed with 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA), which undergoes fluorescence emission after interaction with intracellular ROS, and it was effectively decreased by nanoparticle administration by 200%. Preliminary analyses performed by qRT-PCR demonstrated compensatory effects on transcriptional levels of Cat, Sod1 and Sod2 genes upon NC administration. Cell cultures fixed aboard the ISS were found to be fully adherent and differentiated after return on Earth
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
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
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