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39 results on '"De Santo, Maria"'

1. Inversion Ring in Chromonic Twisted Hedgehogs: Theory and Experiment

Author

Ciuchi, Federica, De Santo, Maria Penelope, Paparini, Silvia, Spina, Lorenza, and Virga, Epifanio G.

Subjects
Condensed Matter - Soft Condensed Matter, Mathematical Physics
Abstract

Twisted hedgehogs are defects in spherical cavities with homeotropic anchoring for the nematic director that arise when twist distortions are sufficiently less energetic than splay (and bend) distortions. They bear a characteristic inversion ring, where the director texture changes the sense it spirals about the center of the cavity. This paper applies a quartic twist theory recently proposed to describe the elasticity of chromonics to explain a series of inversion rings observed in aqueous solutions of SSY at two different concentrations. The theory features a phenomenological length a, whose measure is extracted from the data and shown to be fairly independent of the cavity radius, as expected for a material constant.

Published
2024

2. Flexible Physical Unclonable Functions based on non-deterministically distributed Dye-Doped Fibers and Droplets

Author

Bruno, Mauro Daniel Luigi, Lio, Giuseppe Emanuele, Ferraro, Antonio, Nocentini, Sara, Papuzzo, Giuseppe, Forestiero, Agostino, Desiderio, Giovanni, De Santo, Maria Penelope, Wiersma, Diederik Sybolt, Caputo, Roberto, Golemme, Giovanni, Riboli, Francesco, and Barberi, Riccardo Cristoforo

Subjects
Condensed Matter - Materials Science, Condensed Matter - Soft Condensed Matter, Electrical Engineering and Systems Science - Image and Video Processing, Physics - Applied Physics, Physics - Chemical Physics, Physics - Optics
Abstract

The development of new anti-counterfeiting solutions is a constant challenge and involves several research fields. Much interest is devoted to systems that are impossible to clone, based on the Physical Unclonable Function (PUF) paradigm. In this work, new strategies based on electrospinning and electrospraying of dye-doped polymeric materials are presented for the manufacturing of flexible free-standing films that embed different PUF keys. Films can be used to fabricate anticounterfeiting labels having three encryption levels: i) a map of fluorescent polymer droplets, with non deterministic positions on a dense yarn of polymer nanofibers; ii) a characteristic fluorescence spectrum for each label; iii) a challenge-response pairs (CRPs) identification protocol based on the strong nature of the physical unclonable function. The intrinsic uniqueness introduced by the deposition techniques encodes enough complexity into the optical anti-counterfeiting tag to generate thousands of cryptographic keys. The simple and cheap fabrication process as well as the multilevel authentication makes such colored polymeric unclonable tags a practical solution in the secure protection of merchandise in our daily life.

Published
2023

6. Macroscopic Biaxial Order in Multilayer Films of Bent-Core Liquid Crystals Deposited by Combined Langmuir–Blodgett/Langmuir–Schaefer Technique

Author

Vita, Francesco, primary, Adamo, Fabrizio Corrado, additional, Campana, Mario, additional, Bordokas, Blake, additional, Ciuchi, Federica, additional, De Santo, Maria Penelope, additional, Hermida-Merino, Daniel, additional, Lisovsky, Angela, additional, Pisani, Michela, additional, Pontoni, Diego, additional, Scharrer, Eric, additional, and Francescangeli, Oriano, additional

Published
2024
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7. Fabrication of Electrospun Keratin Nanofiber Membranes for Air and Water Treatment

Author

Figoli, Alberto, Ursino, Claudia, Ramirez, Diego Omar Sanchez, Carletto, Riccardo Andrea, Tonetti, Cinzia, Varesano, Alessio, De Santo, Maria Penelope, Cassano, Alfredo, and Vineis, Claudia

Subjects
Porous Materials Inc., Keratin -- Mechanical properties, Nylon -- Mechanical properties, Permeability -- Mechanical properties, Methylene blue -- Mechanical properties, Adsorption -- Mechanical properties, Proteins -- Mechanical properties, Wool, Engineering and manufacturing industries, Science and technology
Abstract

Keratin proteins extracted from wool fibers by sulfitolysis were electrospun for the production of active nanofiber membranes (NFMs). The keratin NFMs were composited with nylon woven fabric for improving their mechanical properties as a filtration material. The prepared membranes were characterized in terms of morphology, pore size, contact angle, and performance of water and air permeability. Experimental data showed that most of investigated parameters were affected by the electrospinning time: that is, roughness rose by increasing the electrospinning time, while the narrowest pore size distribution was obtained at the longest electrospinning time (2 h). The pure water permeability (PWP) was greater for the produced NFMs than for the commercial microfiltration membranes and decreased by increasing the electrospinning time. At the longest electrospinning time, the produced NFMs showed a PWP of about 45.7 [m.sup.3]/[m.sup.2] h bar, which is a value greater than those obtained by conventional materials used in water filtration, including microfiltration membranes. According to the data of contact angle measurements, the high hydrophobicity of NFMs membranes could reinforce their stability in water. Other potential applications could be venting, adsorption of VOCs, and separation of oils from oil/water emulsions., INTRODUCTION Keratins are naturally fibrous proteins found in animal tissues, including hair, wool, and horns, characterized by high chemical stability due to the presence of many cysteine residues (7-20%) forming [...]

Published
2019
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10. Chiral Chromonics Confined in Spherical Geometries.

Author

De Santo, Maria Penelope, Spina, Lorenza, and Ciuchi, Federica

Subjects
LIQUID crystal states, LIQUID crystals, NEMATIC liquid crystals, CHOLESTERIC liquid crystals
Abstract

Chromonic liquid crystals have recently received a lot of attention due to their spontaneous self-assembly in supramolecular columnar structures that, depending on their concentration in water, align to form a nematic liquid crystalline phase. The chirality may be induced in chromonics by adding chiral moieties to the nematic phase or enhanced by confining them in curved geometrical constraints. This review summarizes the recent research developments on chiral chromonic liquid crystals confined in spherical geometry, relating the results to what was observed for thermotropic liquid crystals in the same conditions. The review focuses on the studies carried out on commercially available nematic chromonics, investigating the effects on their topologies in different anchoring conditions and different chiral dopants and suggesting an application in the sensor field. [ABSTRACT FROM AUTHOR]

Published
2023
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18. Comparison of pure and mixed gas permeation of the highly fluorinated polymer of intrinsic microporosity PIM-2 under dry and humid conditions: Experiment and modelling

Author

Fuoco, Alessio, primary, Satilmis, Bekir, additional, Uyar, Tamer, additional, Monteleone, Marcello, additional, Esposito, Elisa, additional, Muzzi, Chiara, additional, Tocci, Elena, additional, Longo, Mariagiulia, additional, De Santo, Maria Penelope, additional, Lanč, Marek, additional, Friess, Karel, additional, Vopička, Ondřej, additional, Izák, Pavel, additional, and Jansen, Johannes C., additional

Published
2020
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21. Gi Protein Modulation of the Potassium Channel TASK-2 Mediates Vesicle Osmotic Swelling to Facilitate the Fusion of Aquaporin-2 Water Channel Containing Vesicles

Author

Centrone, Mariangela, primary, De Santo, Maria, additional, Nicotera, Isabella, additional, Labate, Cristina, additional, Ranieri, Marianna, additional, Di Mise, Annarita, additional, Mola, Maria, additional, Mastrodonato, Maria, additional, Elliani, Rosangela, additional, Barberi, Riccardo, additional, Formoso, Vincenzo, additional, Tamma, Grazia, additional, and Valenti, Giovanna, additional

Published
2018
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24. E-training for the CLIL teacher: e-tutoring and cooperation in a Moodle-based community of learning

Author

DE SANTO, Maria and DE MEO, Anna

Subjects
060201 languages & linguistics, CLIL, teacher training, online learning community, e-tutor, CLIL, 05 social sciences, 050301 education, 06 humanities and the arts, teacher training, online learning community, e-tutor, lcsh:LB5-3640, lcsh:Theory and practice of education, 0602 languages and literature, ComputingMilieux_COMPUTERSANDEDUCATION, 0503 education
Abstract

The multicultural and plurilingual dimension of contemporary European society together with the growing interest in CLIL (Content and Language Integrated Learning) educational approach determined an increasing demand of methodological training for the CLIL teacher in Italy, also following the recent Educational Reform introducing CLIL instruction in upper secondary schools. This scenario encouraged the Orientale University to develop a blended methodological training course for CLIL teachers, integrating face-to-face activities with Web 2.0 virtual classrooms. This paper focuses on the online component of the course as it offered teachers the opportunity to experiment with new training environments based on technology, interaction and collaboration. Particular attention is given to the nature of the interactions among teachers and on the role of the e-tutor, acting as mediator and facilitator of learning and supporting the process of community building in the virtual learning environment. Data collection and observation confirmed that online collaborative activities not only helped teachers acquiring the methodological contents of the course but also contributed to the formation of an online community of learning that, with the constant presence of the e-tutor and the support of a well-structured virtual classroom, contributed to the success of the whole training programme., Journal of e-Learning and Knowledge Society, Vol 12, No 3 (2016): Special Issue: EMEMITALIA Conference 2016

Published
2016
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25. Mitochondrial heteroplasmy profiling in single human oocytes by next-generation sequencing

Author

Ancora, Massimo, primary, Orsini, Massimiliano, additional, Colosimo, Alessia, additional, Russo, Valentina, additional, Marcacci, Maurilia, additional, De Santo, Maria, additional, D’Aurora, Marco, additional, Stuppia, Liborio, additional, Gatta, Valentina, additional, Barboni, Barbara, additional, Cammà, Cesare, additional, and Mattioli, Mauro, additional

Published
2017
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27. Multiscale Investigation of the Depth-Dependent Mechanical Anisotropy of the Human Corneal Stroma

Author

Labate, Cristina, Lombardo, Marco, De Santo, Maria P., Dias, Janice, Ziebarth, Noel M., and Lombardo, Giuseppe

Subjects
Adult, Male, Materials science, Corneal Stroma, Microscopy, Atomic Force, Cornea, Elasticity Imaging Techniques, Atomic force microscopy, Young Adult, Stroma, Elastic Modulus, Microscopy, medicine, Humans, Lamellar structure, Elasticity (economics), Anisotropy, Elastic modulus, Aged, Aged, 80 and over, Anatomy, Middle Aged, Models, Theoretical, Elasticity, medicine.anatomical_structure, Female, Collagen, Biomedical engineering
Abstract

The histology and, accordingly, biomechanics of the human corneal stroma are highly heterogeneous. There is extensive knowledge on the existence of regional differences in the collagen fibril bundles' packing arrangement and lamellar orientation across and throughout the thickness of the human corneal stroma.1–5 The anterior stroma consists of short bundles of collagen fibrils that show dense intertwining and also insert vertically into Bowman's layer, thus contributing to maintain corneal shape. The deeper stroma contains collagen fibril bundles that are arranged in wide lamellae oriented predominantly along the superior/inferior and nasal/temporal meridians and with reduced connections between adjacent layers. Several laboratory techniques have been used to elucidate the depth-dependent mechanical properties of the human corneal stroma.6–17 All of these studies have shown that the elastic modulus within the stroma decreases from anterior to posterior, regardless of the mechanical testing used. It is therefore well accepted that the depth-dependent changes of stromal mechanical elasticity are linked to the depth-dependent change of stromal microstructure. Atomic force microscopy (AFM) enables localized mechanical sample testing and has been used to investigate the local elastic modulus of the human corneal stroma at different depths. Although the results from previous studies6–11 could not be directly compared, because of the use of AFM tips with variable geometry and dimension as well as different study protocols, the elastic modulus is shown to decrease 40% to 80% with depth from the anterior stroma to the posterior part of the stroma. The aim of this study was to provide information on the depth-dependent compressive elastic modulus of the human corneal stroma both at the tissue (stroma) and molecular (collagen) level by using AFM. In addition, we correlated the depth-dependent anisotropy of stromal elasticity with images of the human corneal stroma acquired by second harmonic generation (SHG) microscopy.

Published
2015

33. Mechanical Resilience of Modified Bitumen at Different Cooling Rates: A Rheological and Atomic Force Microscopy Investigation.

Author

Rossi, Cesare Oliviero, Ashimova, Saltanat, Calandra, Pietro, De Santo, Maria Penelope, and Angelico, Ruggero

Subjects
BITUMEN, ATOMIC force microscopy
Abstract

Due to the wide variation in geographic and climatic conditions, the search for high-performance bituminous materials is becoming more and more urgent to increase the useful life of pavements and reduce the enormous cost of road maintenance. Extensive research has been done by testing various bitumen modifiers, although most of them are petroleum-derived additives, such as polymers, rubbers and plastic, which in turn do not prevent oxidative aging of the binder. Thus, as an alternative to the most common polymeric rheological modifiers, selected binder additives falling in the categories of organosilane (P2KA), polyphosphoric acid (PPA) and food grade phospholipids (LCS) were homogeneously mixed to a base bitumen. The goal was to analyse the micro-morphology of the bitumens (neat and modified) subjected to different cooling rates and to find the corresponding correlations in the mechanical response domain. Therefore, microstructural investigations carried out by Atomic Force Microscopy (AFM) and fundamental rheological tests based on oscillatory dynamic rheology, were used to evaluate the effect of additives on the bitumen structure and compared with pristine binder as a reference. The tested bitumen additives have been shown to elicit different mechanical behaviours by varying the cooling rate. By comparing rheological data, analysed in the framework of the "weak gel" model, and AFM images, it was found that both P2KA and PPA altered the material structure in a different manner whereas LCS revealed superior performances, acting as "mechanical buffer" in the whole explored range of cooling rates. [ABSTRACT FROM AUTHOR]

Published
2017
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36. Paper like cholesteric interferential mirror

Author

Petriashvili, Gia, primary, Japaridze, Kokhta, additional, Devadze, Lali, additional, Zurabishvili, Cisana, additional, Sepashvili, Nino, additional, Ponjavidze, Nino, additional, De Santo, Maria P., additional, Matranga, Mario A., additional, Hamdi, Ridha, additional, Ciuchi, Federica, additional, and Barberi, Riccardo, additional

Published
2013
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