3,116 research outputs found
Facile Functionalization of Charcoal by a Green Approach
No full textThe ability of charcoal, a low-cost material derived from biomass pyrolysis, to be functionalized via cation exchange in an aqueous solution, providing new interesting fillers with possible antimicrobial and flame-retardant properties, is discussed here. The adducts obtained through this sustainable procedure, show a significant uptake of close to 30% by weight of well-known quaternary phosphonium salts, tetraphenyl phosphonium bromide, and dodecyl triphenyl phosphonium bromide. The new functionalized materials were characterized by elemental analysis, wide-angle X-ray diffraction, infrared spectroscopy, and thermogravimetry. Additionally, a study of changing the ratio between the reagents for both adducts was performed to improve salt uptake and optimize the cationic exchange. Dispersibility tests showed the ability of functionalization to deeply change the polarities of the carbon materials to modify the compatibility and improve the possible interactions with different media, such as different polymer matrices
Variable density randomized stack of spirals (VDR-SoS) for compressive sensing MRI
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CREPE: A first mathematical model for crosstalking of endothelial cells and hepatocyte metabolism
No full textAccelerating 4D flow MRI by exploiting low-rank matrix structure and hadamard sparsity
No full textPurpose: To develop accelerated 4D flow MRI by exploiting low-rank matrix structure and Hadamard sparsity. Theory and Methods: 4D flow MRI data can be represented as the sum of a low-rank and a sparse component. To optimize the sparse representation of the data, it is proposed to incorporate a Hadamard transform of the velocity-encoding segments. Retrospectively and prospectively, undersampled data of the aorta of healthy subjects are used to assess the reconstruction accuracy of the proposed method relative to k-t SPARSE-SENSE reconstruction. Image reconstruction from eight-fold prospective undersampling is demonstrated and compared with conventional SENSE imaging. Results: Simulation results revealed consistently lower errors in velocity estimation when compared with k-t SPARSE-SENSE. In vivo data yielded reduced error of peak flow with the proposed method relative to k-t SPARSE-SENSE when compared with two-fold SENSE ( 2.5±4.6% versus 10.2±8.5% in the ascending aorta, 3.6±8.4% versus 9.2±9.0% in the descending aorta). Streamline visualization showed more consistent flow fields with the proposed technique relative to the benchmark methods. Conclusion: Image reconstruction by exploiting low-rank structure and Hadamard sparsity of 4D flow MRI data improves the reconstruction accuracy relative to current state-of-the-art methods and holds promise to reduce the long scan times of 4D flow MRI
A novel 3D Cartesian random sampling strategy for Compressive Sensing Magnetic Resonance Imaging
No full textIn this work we propose a novel acquisition strategy for accelerated 3D Compressive Sensing Magnetic Resonance Imaging (CS-MRI). This strategy is based on a 3D cartesian sampling with random switching of the frequency encoding direction with other K-space directions. Two 3D sampling strategies are presented. In the first strategy, the frequency encoding direction is randomly switched with one of the two phase encoding directions. In the second strategy, the frequency encoding direction is randomly chosen between all the directions of the K-Space. These strategies can lower the coherence of the acquisition, in order to produce reduced aliasing artifacts and to achieve a better image quality after Compressive Sensing (CS) reconstruction. Furthermore, the proposed strategies can reduce the typical smoothing of CS due to the limited sampling of high frequency locations. We demonstrated by means of simulations that the proposed acquisition strategies outperformed the standard Compressive Sensing acquisition. This results in a better quality of the reconstructed images and in a greater achievable acceleration
New Imaging Frontiers in Cardiology: Fast and Quantitative Maps from Raw Data
No full textAmong the novelties in the field of cardiovascular imaging, the construction of quantitative maps in a fast and efficient way is one of the most interesting aspects of the clinical research. Quantitative parametric maps are typically obtained by post processing dynamic images, that is, sets of images usually acquired in different temporal intervals, where several images with different contrasts are obtained. Magnetic resonance imaging, and emission tomography (positron emission and single photon emission) are the imaging techniques best suited for the formation of quantitative maps
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Trust in authorities monitoring the distribution of genetically modified foods: dimensionality, measurement issues, and determinants
No full textBased on a combined internet and mail survey in Germany the independence of indica-tors of trust in public authorities from indicators of attitudes toward genetically modified food is tested. Despite evidence of a link between trust indicators on the one hand and evaluation of benefits and perceived likelihoods of risks, correlation with other factors is found to be moderate on average. But the trust indicators exhibit only a moderate relation with the re-spondents’ preference for either sole public control or a cooperation of public and private bodies in the monitoring of GM food distribution. Instead, age and location in either the New or the Old Lander are found to be significantly related with such preferences
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A critical account of the relationship between institutional trust, risk perception, and technology acceptance with an application to genetically modified foods
No full textThis article critically reflects on the widely held view of a causal chain with trust in public authorities impacting technology acceptance via perceived risk. It first puts forward conceptual reason against this view, as the presence of risk is a precondition for trust playing a role in decision making. Second, results from consumer surveys in Italy and Germany are presented that support the associationist model as counter hypothesis. In that view, trust and risk judgments are driven by and thus simply indicators of higher order attitudes toward a certain technology which determine acceptance instead. The implications of these findings are discussed
PER UNA EDIZIONE CRITICA DELLE RIME DI BARTOLOMEO CAVASSICO
Full text linkThis PhD thesis consists of:
- An introductory part presenting the figure of the author, a description of the ms. bearing the Rime, an analysis of the form and content of the texts and the social, political and cultural context where they were produced;
- The critical edition of fifty-four poems in italian and fifteen in Bellunese dialect. An introductory cap presents the formal characteristics of the work and provides the context, if necessary; this is followed by the text, reproduced according to generally conservative criteria; at the bottom there is a first band of apparatus, aimed at containing corrections of servile errors; a second band, containing the actual genetic apparatus, bearing any variants or previous redactions of the text; and finally the commentary, aimed at clarifying critical places and pointing out parallels with other authors. For the Bellunese texts, a full translation was also provided.
- A caption index;
- Two lexical indexes, for italian and Bellunese texts, bearing the notable forms;
- Four appendices. Appendix I is a table containing all the poems, classified according to the following criteria: location in the ms., title, genre of the poem, language, possible addressee and brief summary, focusing, in particular, on the (recurring) themes present in the text. Appendix II houses vernacular texts not included in the edition, and Appendix III italian texts that the author has taken from other printings. Appendix IV contains the digital reproduction of six papers from ms. 396 of the Biblioteca Civica of Belluno.Questa tesi di dottorato si compone di:
- Una parte introduttiva che presenta la figura dell'autore, la descrizione del ms. recante le Rime, l'analisi della forma e dei contenuti dei testi e il contesto sociale, politico e culturale in cui sono stati prodotti;
- L'edizione critica commentata di cinquantaquattro poesie in volgare e quindici in dialetto bellunese. Un cappello introduttivo presenta le caratteristiche formali dell'opera e ne fornisce il contesto, qualora necessario; segue il testo, riprodotto secondo criteri generalmente conservativi; in calce si trovano una prima fascia di apparato, volta a contenere le correzioni degli errori servili, una seconda fascia, contenente l'apparato genetico vero e proprio, recante le eventuali varianti o redazioni precedenti del testo, e infine il commento, finalizzato a chiarire i luoghi critici e a segnalare paralleli con altri autori. Per i testi bellunesi si è fornita anche la traduzione integrale in calce.
- Un indice dei capoversi;
- Due indici lessicali, per i testi in volgare e per i testi in bellunese, recanti le forme notevoli;
- Quattro appendici. L'appendice I è una tabella contenente tutti i componimenti, classificati secondo i seguenti criteri: collocazione nel ms., titolo, genere del componimento, lingua, eventuale destinatario e breve riassunto, imperniato, in particolare, sui temi (ricorrenti) presenti nel testo. L'appendice II ospita i testi in volgare non inclusi nell'edizione, mentre l'appendice III i testi in volgare che l'autore ha tratto da altre stampe. L'appendice IV contiene la riproduzione digitale di sei carte del ms. 396 della Biblioteca Civica di Belluno, attraverso la quale si possono osservare la scrittura del notaio e gli interventi sui testi
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