1,720,974 research outputs found
Sol-gel inks for Additive Manufacturing of ceramic-based materials
No full textAdditive manufacturing processes have represented a milestone breakthrough over a broad range of technologies, enabling the fabrication of three-dimensional structures with utterly unique architectures over different length scales. Significant efforts have been devoted thus far to developing feedstock formulations for the fabrication of components with previously unattainable degrees of complexity over a wide range of materials, including ceramics, polymers and metals. Significant possibilities exist to further extend this fabrication concept to several industrial sectors, thus contributing to enrich the panel of materials of scientific and technological interest. Here we explore the coupling of AM technologies with various sol-gel-based methodologies to create ceramic components with different nanoarchitectures.
Glass has traditionally earned a privileged position in different applications, spanning from the fabrication of artistic endeavours, packaging and windows in our homes, to more technological fields and scientific research. Modern manufacturing techniques have delved deeply into developing fabrication methods for creating complex 3D printed glass components; however, further refinement is imperative to enhance the final optical quality. We report a novel approach to prepare sol-gel-based photocurable feedstocks compatible with UV-assisted direct ink writing and DLP techniques, demonstrating high chemical flexibility and great potential in tuning the optical properties. Complex-structured parts were printed and successfully converted into fully dense, transparent and crack-free silica-zirconia, silica-titania and silica-zirconia-titania glasses. Furthermore, we develop a feasible protocol for the fabrication of hierarchical porous titanium carbide/carbon nanocomposite via DLP, designing a bottom-up approach to achieve a fine control over the organisation and positioning of the structural units, with particular focus on nanoscale porosity to adhere to the standards required for nuclear applications. By easily playing with the choice of the network-forming motifs, the synthetic strategy allows for a large variety of modifications and is extended to the fabrication of other systems, including lanthanum dicarbide/carbon and uranium dicarbide/carbon materials.
Therefore, the novel approaches herein proposed hold great promise in broadening the field of ceramic-AM, providing reliable synthetic routes that allow to overcome the several limitations of conventional manufacturing processes. Moreover, the extraordinary variability of the chemical pathways paves the way for the development of advanced custom-made materials
The association between neurocognitive disorders and gustatory dysfunction: a systematic review and meta-analysis
Full text linkOlfactory and gustatory dysfunction have been reported in mild and major neurocognitive disorders (NCDs), with variable results. While olfactory dysfunction has been consistently explored, reports on gustatory alterations are limited. We systematically reviewed case-control studies evaluating gustatory function in NCDs with various etiologies and different neuropathology. Eighteen studies were included in the systematic review, and eight were included in the meta-analysis. Most studies were on Alzheimer's disease (AD) and Parkinson's disease (PD). Pooled analyses showed worse global taste threshold and identification (sour in particular) scores in AD than controls and worse global, sweet, and sour scores in AD compared to mild cognitive impairment (MCI). PD with MCI showed worse global, sweet, salty, and sour scores than controls and cognitively unimpaired PD. Taste dysfunction was differentially associated with the severity of cognitive deficits. Gustatory dysfunction may represent a potential cross-disease chemosensory biomarker of NCD. Whether gustatory alterations may be a pre-clinical biomarker of NCD requires further studies
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
Pain, smell, and taste in adults: a narrative review of multisensory perception and interaction
Full text linkEvery day our sensory systems perceive and integrate a variety of stimuli containing information vital for our survival. Pain acts as a protective warning system, eliciting a response to remove harmful stimuli; it may also be a symptom of an illness or present as a disease itself. There is a growing need for additional pain-relieving therapies involving the multisensory integration of smell and taste in pain modulation, an approach that may provide new strategies for the treatment and management of pain. While pain, smell, and taste share common features and are strongly linked to emotion and cognition, their interaction has been poorly explored. In this review, we provide an overview of the literature on pain modulation by olfactory and gustatory substances. It includes adult human studies investigating measures of pain threshold, tolerance, intensity, and/or unpleasantness. Due to the limited number of studies currently available, we have structured this review as a narrative in which we comment on experimentally induced and clinical pain separately on pain-smell and pain-taste interaction. Inconsistent study findings notwithstanding, pain, smell, and taste seem to interact at both the behavioral and the neural levels. Pain intensity and unpleasantness seem to be affected more by olfactory substances, whereas pain threshold and tolerance are influenced by gustatory substances. Few pilot studies to date have investigated these effects in clinical populations. While the current results are promising for the future, more evidence is needed to elucidate the link between the chemical senses and pain. Doing so has the potential to improve and develop novel options for pain treatment
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
Olfaction and taste in Parkinson's disease: the association with mild cognitive impairment and the single cognitive domain dysfunction
No full textMild cognitive impairment (MCI) and chemosensory dysfunction are non-motor symptoms of Parkinson's disease (PD), but their association is unclear. We explored if MCI and the involvement of single cognitive domains influence olfaction and taste in PD. The role of demographic, clinical and neuropsychiatric variables was tested. We recruited 50 PD patients without dementia, no other reasons for cognitive impairment, no condition that could influence evaluation of cognition, olfaction and taste. They underwent a full neuropsychological and chemosensory (i.e., olfaction and taste) test with the Sniffin' Sticks Extended test (SSET), Whole Mouth test (WMT) and Taste Strips test (TST). Fifty age- and sex-matched healthy subjects served as controls. Olfactory function and sweet identification were worse in PD than controls. MCI negatively influenced odor identification. Factors associated with poor olfactory function were age, overall cognition, apathy, and visuospatial dysfunction. Sour identification was affected by MCI and executive dysfunction, and salty identification by executive dysfunction. MCI, age and executive dysfunction worsened TST score. Awareness of olfactory dysfunction was impaired in PD with MCI. Education positively influenced SSET and TST scores. Our data confirmed that olfaction is abnormal in PD, while taste was only slightly impaired. Olfaction was worse in PD patients with visuospatial dysfunction, while sour and salty identification was worse in those with MCI and executive dysfunction, suggesting different underlying anatomical abnormalities. Future studies should incorporate neuroimaging and cerebrospinal fluid data to confirm this hypothesis. SSET odor identification and TST sour identification could be explored as quick screening tests for PD-MCI
Sucrose-based sol-gel synthesis of microporous titanium carbide as target material for the production of radioisotopes
No full textAn environment-friendly route for the synthesis of titanium carbide by sol-gel processing is reported. The initial
solution is prepared via a simple one-pot approach, using titanium isopropoxide and sucrose as molecular pre-
cursors under acidic conditions, therefore promoting intimate interactions between the networks of sucrose and
of the titanium alkoxide-derived inorganic polymer at the molecular level. Furthermore, the usage of sucrose
represents an established and green solution, and provides a viable alternative to the use of toxic compounds. The
resulting gels are dried at 120 ◦C and then undergo carbothermal reduction in Ar atmosphere at different
temperatures ranging from 700 ◦C to 1750 ◦C. A systematic study of the obtained material is carried out by using
FT-IR spectroscopy, X-ray diffraction, Scanning Electron Microscopy, Raman spectroscopy, N2 physisorption and
He pycnometry. The characterization techniques show that the sucrose-derived titanium carbide exhibits a
tailored microporous structure and larger specific surface area values compared with those of materials produced
using the hazardous phenolic resin-based system. This method thus allows the synthesis of titanium carbide with
exquisite textural properties and attractive porous architectures, meeting the requirements for the fabrication of
target materials in the field of nuclear medicine, with particular interest in the production and release of
scandium radioisotopes
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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