1,721,066 research outputs found
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
Epiregulin-loaded PLGA nanoparticles increase human keratinocytes proliferation: preliminary data
Full text linkOBJECTIVE:Epiregulin is a member of the epidermal growth factor (EGF) family produced by keratinocytes: the aim of this study was to investigate the ability of biocompatible nanoparticles loaded with such growth factor to increase human keratinocytes proliferation.
MATERIALS AND METHODS:Different PLGA (Poly-d,l-lactide-co-glycolide)-nanoparticles (NPs) formulations have been characterized in size and zeta potential by dynamic light scattering (DLS) analysis. The ability of the different PLGA-NPs formulations to adhere onto dental surfaces has been tested, and epiregulin-enriched PLGA-NPs has been produced. Epiregulin release from NPs has been tested by enzyme-linked immunosorbent (ELISA) assay and the proliferative effects of epiregulin-NPs on human keratinocytes have been evaluated.
RESULTS:DLS analysis revealed a different size distribution depending on the PLA/PGA (poly lactic acid/poly glycolic acid) ratio used. 50:50 PLGA-NPs exhibited the smaller size and the best dental adhesive ability. Moreover, such epiregulin-loaded NPs was able to increase cell proliferation.
CONCLUSIONS:Direct dental pocket drug delivery implies the NPs solution loading onto the dental surface at the cement-enamel junction level: 50:50 PLGA-NPs, with their small size and excellent adhesive ability, represent an interesting tool to deliver epiregulin directly where there is the need for epithelial proliferation. These results describe a possible strategy for periodontal pocket delivery of Epiregulin-loaded PLGA-NPs and might provide a new approach for the treatment of gingival recession, where gingival epithelium proliferation is needed
First-line steroid treatment for spontaneous intracranial hypotension
Full text linkBackground: Spontaneous intracranial hypotension (SIH) is a syndrome characterized by low cerebrospinal fluid (CSF) pressure and postural headaches, and affects 1 per 20,000 individuals every year. Case report: We report an otherwise healthy 38-year-old man admitted to the hospital with orthostatic headache that developed 48 h after a short-haul flight during which he sustained a neck injury due to turbulence. Neurological examination, blood analysis and computed tomography scan performed at the emergency service were normal. Brain and spine magnetic resonance imaging (MRI) showed diffuse pachymeningeal enhancement and contrast medium egress from the subarachnoid space into the epidural space at the level of C2. The patient was treated with bed rest, hydration and 1 mg/kg/day oral prednisone for 5 days, with a gradual withdrawal in the following 7 days. Complete symptomatic relief was observed after 16 days, with resolution of the pathological findings on brain and spinal MRI after 1 month, except for localized pachymeningeal enhancement. Clinical relief was maintained over time until last follow-up visit 9 months later. Conclusion: Successful conservative treatment barely exceeds one quarter of cases of SIH. The clinical benefits of steroids may result from several mechanisms of action, for example, improving brain oedema and inflammation, determining fluid retention, and facilitating reabsorption of the CSF from extradural space. Notwithstanding that epidural blood patch remains the most successful treatment for SIH, future studies should explore the effectiveness of steroids as first-line therapy in addition to the most commonly suggested measures of bed rest and hydration
Nano-Functionalized Electrochemical Sensors by Aerosol Jet Printing
No full textIn the latest years, hydrogen peroxide quantification gained a growing interest in many fields both in industry and in the clinical environment. Among the different available methods, electrochemical transducers are of particular interest thanks to their ease of fabrication, convenient integration with microfluidics and electronics and their time and cost-effectiveness. Despite these advantages, electrochemical transducers are affected by many metrological issues. In this work, the novel technique of Aerosol jet printing (AJP) is exploited to fabricate fully printed nanostructured electrochemical sensors for hydrogen peroxide detection. Two different carbon-based printable nanostructures, carbon nanotubes (CNTs) and graphene, are employed to conveniently modify with the same technique electrodes' surfaces. The performances of the proposed design, production process and the different functionalization are explored and discussed. After a preliminary evaluation of the electrochemical characteristics of the printed devices, tests in hydrogen peroxide are carried on. Both materials present a limit of detections (LODs) and sensitivity comparable with the ones obtained in the literature, even though CNT better performs than graphene in terms of sensitivity (20 versus 2.8 mu mM(-2)). The latter presents however a signal-to-noise ratio (SNR) of 51.2 dB that outperforms the one of CNT (26.5 dB) and thus it has a better resistance against noise. Overall, both the evaluated nanostructures appear suitable to improve the metrological characteristics of printed electrochemical sensors and ease their spreading as environmental control devices, and diagnostic tools and assess quality in the industrial environment
3d electrochemical sensor and microstructuration using aerosol jet printing
Full text linkElectrochemical sensors are attracting great interest for their different applications. To improve their performances, basic research focuses on two main issues: improve their metrological characteristics (e.g., repeatability, reusability and sensitivity) and investigate innovative fabrication processes. In this work, we demonstrate an innovative microstructuration technique aimed at increasing electrochemical sensor sensitivity to improve electrode active area by an innovative fabrication technique. The process is empowered by aerosol jet printing (AJP), an additive-manufacturing and non-contact printing technique that allows depositing functional inks in precise patterns such as parallel lines and grids. The 3D printed microstructures increased the active surface area by up to 130% without changing the substrate occupancy. Further, electrochemical detection of ferro/ferri-cyanide was used to evaluate the sensitivity of the electrodes. This evaluation points out a sensitivity increase of 2.3-fold on average between bare and fully microstructured devices. The increase of surface area and sensitivity are well linearly correlated as expected, verifying the fitness of our production process. The proposed microstructuration is a viable solution for many applications that requires high sensitivity, and the proposed technique, since it does not require masks or complex procedures, turns out to be flexible and applicable to infinite construction geometries
Pre-odontoblast proliferation induced by near-infrared laser stimulation
Full text linkOBJECTIVE: Laser therapy is known to stimulate cell proliferation and differentiation, an effect called "biostimulation". Although many clinical applications of laser therapy take advantage from such positive effect, the underlying molecular mechanisms are not fully understood. The aim of this work was to investigate the effect of near-infrared laser stimulation on rat pre-odontoblast cells (MDPC-23 cells) and the molecular mechanism/s involved.
MATERIALS AND METHODS: MDPC-23 cells were stimulated with a near-infrared (980 nm) laser source with different energy settings (1-50 J, corresponding to 0.65-32.47 J/cm2) and cell proliferation was evaluated by manual count. ERK 1/2 pathway activation was evaluated by Western blot analysis.
RESULTS: 1-10 J stimulation (corresponding to 0.65-6.5 J/cm2) significantly increase MDPC-23 cell proliferation and such effect seems to be mediated by ERK 1/2 signalling pathway activation, showing a key role of ERK 1/2 pathway in mediating the proliferative response induced by laser stimulation.
CONCLUSIONS: Near infrared laser stimulation with low energies (1-10 J) is able to increase cell proliferation through ERK 1/2 signalling pathway activation. At the same time, higher energy stimulation (25-50 J) induces an initial toxic effect, probably activating pro-apoptotic signalling molecules, downstream ERK 1/2 kinase. Such results foster the application of this therapeutic approach in different clinical settings in which a regenerative tissue response is needed
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