88 results on '"Alessandro Sala"'
Search Results
2. A trust assurance technique for Internet of things based on human behavior compliance.
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Marco Anisetti, Claudio Agostino Ardagna, Ernesto Damiani, and Alessandro Sala
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- 2021
- Full Text
- View/download PDF
3. Eine Vorgehensweise zur Evaluierung von Industrie 4.0 Use Cases.
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Manfred Rosenberger, Alexander Stocker, Marius Lütkemeyer, Alessandro Sala, Gernot Lechner, Andreas Felsberger, and Gerald Reiner
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- 2019
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4. How to have two careers, and be happy with both
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Alessandro Sala
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Multidisciplinary - Published
- 2023
5. Why and How Innovation Vouchers Work: Disentangling the Roles of Serendipity and Funding
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Andrea Caragliu, Michele Coletti, Paolo Landoni, and Alessandro Sala
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output additionality ,Urban Studies ,innovation vouchers ,non-geographical proximity ,innovation policy ,serendipity - Published
- 2022
6. Shaping the image of the heretics: The narratio in Gregory IX’s letters
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Alessandro Sala
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- 2022
7. Versatile procedure for the correction of non-isochromatism in XPEEM spectroscopic imaging
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Sebastian Günther, Tim Kratky, Jürgen Kraus, Paul Leidinger, Patrick Zeller, Alessandro Sala, Francesca Genuzio, Matteo Jugovac, Tevfik Onur Menteş, and Andrea Locatelli
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Instrumentation ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2023
8. Resilienz durch dynamisches Prozessmanagement
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Thomas Knothe, Marius Lütkemeyer, Julia Woesthoff, Alessandro Sala, Alexander Gaal, Nicole Oertwig, and Publica
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Computer science ,business.industry ,Strategy and Management ,Environmental resource management ,General Engineering ,Management Science and Operations Research ,business ,Resilience (network) - Abstract
Krisen treten regelmäßig auf und betreffen aufgrund zunehmender Globalisierung immer mehr Unternehmen gleichzeitig. In diesem Beitrag wird ein Ansatz für ein dynamisches Prozessmanagement vorgestellt, welches die Fähigkeit der Früherkennung von Disruptionen und gleichzeitig auch Routine sowie Agilität im Normal- wie auch im Krisenmodus durchgängig unterstützt.
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- 2021
9. Integration of biomechanical parameters in tetrahedral mass-spring models for virtual surgery simulation.
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Alessandro Sala, Giuseppe Turini, Mauro Ferrari 0001, Franco Mosca, and Vincenzo Ferrari
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- 2011
- Full Text
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10. Identification and evaluation of development paths for technology-oriented industrial companies in structural transformation processes
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Alessandro Sala, Arko Steinwender, Peter Schieder, and Wilfried Sihn
- Published
- 2022
11. Pre-hospital glycemia as a biomarker for in-hospital all-cause mortality in diabetic patients - a pilot study
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Salvatore Greco, Alessandro Salatiello, Francesco De Motoli, Antonio Giovine, Martina Veronese, Maria Grazia Cupido, Emma Pedarzani, Giorgia Valpiani, and Angelina Passaro
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Type 2 diabetes mellitus ,Glycemic variability ,Glucose metabolism disorder ,AdaBoost-FAS ,Machine learning ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Type 2 Diabetes Mellitus (T2DM) presents a significant healthcare challenge, with considerable economic ramifications. While blood glucose management and long-term metabolic target setting for home care and outpatient treatment follow established procedures, the approach for short-term targets during hospitalization varies due to a lack of clinical consensus. Our study aims to elucidate the impact of pre-hospitalization and intra-hospitalization glycemic indexes on in-hospital survival rates in individuals with T2DM, addressing this notable gap in the current literature. Methods In this pilot study involving 120 hospitalized diabetic patients, we used advanced machine learning and classical statistical methods to identify variables for predicting hospitalization outcomes. We first developed a 30-day mortality risk classifier leveraging AdaBoost-FAS, a state-of-the-art ensemble machine learning method for tabular data. We then analyzed the feature relevance to identify the key predictive variables among the glycemic and routine clinical variables the model bases its predictions on. Next, we conducted detailed statistical analyses to shed light on the relationship between such variables and mortality risk. Finally, based on such analyses, we introduced a novel index, the ratio of intra-hospital glycemic variability to pre-hospitalization glycemic mean, to better characterize and stratify the diabetic population. Results Our findings underscore the importance of personalized approaches to glycemic management during hospitalization. The introduced index, alongside advanced predictive modeling, provides valuable insights for optimizing patient care. In particular, together with in-hospital glycemic variability, it is able to discriminate between patients with higher and lower mortality rates, highlighting the importance of tightly controlling not only pre-hospital but also in-hospital glycemic levels. Conclusions Despite the pilot nature and modest sample size, this study marks the beginning of exploration into personalized glycemic control for hospitalized patients with T2DM. Pre-hospital blood glucose levels and related variables derived from it can serve as biomarkers for all-cause mortality during hospitalization.
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- 2024
- Full Text
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12. R&D networks: an evaluation framework.
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Alessandro Sala, Paolo Landoni, and Roberto Verganti
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- 2011
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13. BLUE laser soldering
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Roberto Battista, Alessandro Sala, and Alessandro Maio
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Blue laser ,Materials science ,business.industry ,Soldering ,Optoelectronics ,business - Published
- 2021
14. Black or red phosphorus yields the same blue phosphorus film
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Alessandro Sala, Maria Caporali, Manuel Serrano-Ruiz, Francesco Armillotta, Erik Vesselli, Francesca Genuzio, Tevfik Onur Menteş, Andrea Locatelli, Giovanni Comelli, Cristina Africh, Alberto Verdini, Sala, A, Caporali, M, Serrano-Ruiz, M, Armillotta, F, Vesselli, E, Genuzio, F, Mente, To, Locatelli, A, Comelli, G, Africh, C, and Verdini, A
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Phosphorou ,2D Material ,Phosphorous ,2D Materials ,Au(111) ,General Materials Science - Abstract
After the discovery of graphene, many other 2D materials have been predicted theoretically and successfully prepared. In this context, single-sheet black phosphorus - phosphorene - is emerging as a viable contender in the field of (2D) semiconductors. Phosphorene offers high carrier mobility and an anisotropic structure that gives rise to a modulation of physical and chemical properties. This opens the way to many novel and fascinating applications related to field-effect transistors and optoelectronic devices. In previous studies, a single layer of blue phosphorene intermixed with Au atoms was grown using purified black phosphorus as a precursor. Starting from the observation that phosphorus vapor mainly consists of P clusters, in this work we aimed at obtaining blue phosphorus using much less expensive purified red phosphorus as an evaporant. By means of microscopy, spectroscopy and diffraction experiments, we show that black or red phosphorus deposition on Au(111) substrates yields the same blue phosphorus film.
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- 2022
15. Conservation of Nickel Ion Single‐Active Site Character in a Bottom‐Up Constructed π‐Conjugated Molecular Network
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Daniel Baranowski, Iulia Cojocariu, Alessandro Sala, Cristina Africh, Giovanni Comelli, Luca Schio, Massimo Tormen, Luca Floreano, Vitaliy Feyer, Claus M. Schneider, Baranowski, D., Cojocariu, I., Sala, A., Africh, C., Comelli, G., Schio, L., Tormen, M., Floreano, L., Feyer, V., and Schneider, C. M.
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Nanostructure ,Photoelectron Spectroscopy ,Scanning Probe Microscopy ,Organic Chemistry ,Nanostructures ,Porphyrinoids ,X-Ray Absorption Spectroscopy ,General Chemistry ,General Medicine ,Physik (inkl. Astronomie) ,Catalysis ,Chemical Sciences ,ddc:540 ,Porphyrinoid - Abstract
On-surface chemistry holds the potential for ultimate miniaturization of functional devices. Porphyrins are promising building-blocks in exploring advanced nanoarchitecture concepts. More stable molecular materials of practical interest with improved charge transfer properties can be achieved by covalently interconnecting molecular units. On-surface synthesis allows to construct extended covalent nanostructures at interfaces not conventionally available. Here, we address the synthesis and properties of covalent molecular network composed of interconnected constituents derived from halogenated nickel tetraphenylporphyrin on Au(111). We report that the π-extended two-dimensional material exhibits dispersive electronic features. Concomitantly, the functional Ni cores retain the same single-active site character of their single-molecule counterparts. This opens new pathways when exploiting the high robustness of transition metal cores provided by bottom-up constructed covalent nanomeshes.
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- 2022
16. Disproportionation of Nitric Oxide at a Surface-Bound Nickel Porphyrinoid
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Matus Stredansky, Stefania Moro, Manuel Corva, Henning Sturmeit, Valentin Mischke, David Janas, Iulia Cojocariu, Matteo Jugovac, Albano Cossaro, Alberto Verdini, Luca Floreano, Zhijing Feng, Alessandro Sala, Giovanni Comelli, Andreas Windischbacher, Peter Puschnig, Chantal Hohner, Miroslav Kettner, Jörg Libuda, Mirko Cinchetti, Claus Michael Schneider, Vitaliy Feyer, Erik Vesselli, Giovanni Zamborlini, Stredansky, M., Moro, S., Corva, M., Sturmeit, H., Mischke, V., Janas, D., Cojocariu, I., Jugovac, M., Cossaro, A., Verdini, A., Floreano, L., Feng, Z., Sala, A., Comelli, G., Windischbacher, A., Puschnig, P., Hohner, C., Kettner, M., Libuda, J., Cinchetti, M., Schneider, C. M., Feyer, V., Vesselli, E., and Zamborlini, G.
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Porphyrins ,2D Materials ,Biomimetic Materials ,Disproportionation ,Nitrogen Monoxide ,Single-Atom Catalysts ,Copper ,Ferric Compounds ,Metals ,Oxidation-Reduction ,Nickel ,Nitric Oxide ,Metal ,General Chemistry ,General Medicine ,Physik (inkl. Astronomie) ,Ferric Compound ,Catalysis ,Porphyrin ,Single-Atom Catalyst ,2D Material ,ddc:540 ,ddc:660 ,Biomimetic Material - Abstract
Uncommon metal oxidation states in porphyrinoid cofactors are responsible for the activity of many enzymes. The F₄₃₀ and P450nor co-factors, with their reduced NiI- and FeIII-containing tetrapyrrolic cores, are prototypical examples of biological systems involved in methane formation and in the reduction of nitric oxide, respectively. Herein, using a comprehensive range of experimental and theoretical methods, we raise evidence that nickel tetraphenyl porphyrins deposited in vacuo on a copper surface are reactive towards nitric oxide disproportionation at room temperature. The interpretation of the measurements is far from being straightforward due to the high reactivity of the different nitrogen oxides species (eventually present in the residual gas background) and of the possible reaction intermediates. The picture is detailed in order to disentangle the challenging complexity of the system, where even a small fraction of contamination can change the scenario.
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- 2022
17. 'Inside out' growth method for high-quality nitrogen-doped graphene
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Cinzia Cepek, Daniele Perilli, Sara Fiori, Alessandro Sala, Mirco Panighel, Giovanni Comelli, Hongsheng Liu, Cristiana Di Valentin, Aldo Ugolotti, Cristina Africh, Fiori, S, Perilli, D, Panighel, M, Cepek, C, Ugolotti, A, Sala, A, Liu, H, Comelli, G, Di Valentin, C, Africh, C, Fiori, S., Perilli, D., Panighel, M., Cepek, C., Ugolotti, A., Sala, A., Liu, H., Comelli, G., Di Valentin, C., and Africh, C.
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inorganic chemicals ,Materials science ,Nitrogen ,FOS: Physical sciences ,chemistry.chemical_element ,02 engineering and technology ,Chemical vapor deposition ,010402 general chemistry ,01 natural sciences ,Catalysis ,law.invention ,X-ray photoelectron spectroscopy ,law ,Doping ,General Materials Science ,Defects ,Graphene ,Condensed Matter - Materials Science ,technology, industry, and agriculture ,Materials Science (cond-mat.mtrl-sci) ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Nickel ,chemistry ,Chemical engineering ,Defect ,Scanning tunneling microscope ,0210 nano-technology ,Carbon - Abstract
High-quality nitrogen-doped graphene on nickel is prepared by exploiting both the catalytic properties of nickel and the solubility of nitrogen atoms into its bulk. Following the standard chemical vapor deposition procedure, a previously nitrogen-doped nickel substrate is exposed to carbon-containing precursors so that nitrogen atoms, segregating to the surface, remain trapped in the growing graphene network. Morphological and chemical characterization by scanning tunneling microscopy and X-ray photoelectron spectroscopy demonstrates that the process yields a flat, wide, continuous nitrogen-doped graphene layer. Experimental results are combined with a thorough density functional theory investigation of possible structural models, to obtain a clear description at the atomic scale of the various configurations of the nitrogen atoms observed in the graphene mesh. This growth method is potentially scalable and suitable for the production of high-performance nano-devices with well-defined nitrogen centers, to be exploited as metal-free carbon-based catalysts in several applicative fields such as electrochemistry, energy storage, gas storage/sensing or wastewater treatment., 21 pages, including 4 figures, plus SI
- Published
- 2021
18. Imaging at the mesoscale (leem, peem)
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Alessandro Sala, M. Rocca, L Vattuone, T. Rahman, and Sala, A.
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Diffraction ,Physics ,PEEM ,Cathode lens ,Mesoscale ,LEEM ,Microdiffraction ,Microspectroscopy ,Spectromicroscopy ,Mesoscale meteorology ,Engineering physics - Abstract
The capability to display images containing chemical, magnetic, and structural information and to perform spectroscopy and diffraction from a μm-sized area makes cathode lens electron microscopy one of the most used and reliable techniques to analyze surfaces at the mesoscale. Thanks to its versatility, LEEMlow-energyelectron microscopy (LEEM)/PEEM systems are currently employed to study model systems in the fields of nanotechnology, nanomagnetism, material science, catalysis, energy storage, thin films, and 2-D (two-dimensional) materials. In this chapter, we will present a brief but complete review of this class of instruments. After a historical digression in the introductory section, we will first show the basic operating principles of a simple setup and then the elements that can be added to improve performance. Later, two sections will be dedicated to LEEM and PEEMphotoelectronemission microscopy (PEEM), respectively. In both cases, a theoretical discussion on the contrast mechanisms will prelude to a showcase of the operating modes of the instrument, with clear examples that will show the best performance available today. Finally, a brief discussion about the future developments of cathode lens electron microscopy will close the chapter.
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- 2020
19. 'Inside out' growth method for high-quality nitrogen-doped graphene
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Sara Fiori and Daniele Perilli and Mirco Panighel and Cinzia Cepek and Aldo Ugolotti and Alessandro Sala and Hongsheng Liu and Giovanni Comelli and Cristiana Di Valentin and Cristina Africh
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inorganic chemicals ,Nitrogen ,technology, industry, and agriculture ,Doping ,Chemical vapor deposition ,Defects ,Graphene - Abstract
High-quality nitrogen-doped graphene on nickel is prepared by exploiting both the catalytic properties of nickel and the solubility of nitrogen atoms into its bulk. Following the standard chemical vapor deposition procedure, a previously nitrogen-doped nickel substrate is exposed to carbon-containing precursors so that nitrogen atoms, segregating to the surface, remain trapped in the growing graphene network. Morphological and chemical characterization by scanning tunneling microscopy and X-ray photoelectron spectroscopy demonstrates that the process yields a flat, wide, continuous nitrogen-doped graphene layer. Experimental results are combined with a thorough density functional theory investigation of possible structural models, to obtain a clear description at the atomic scale of the various configurations of the nitrogen atoms observed in the graphene mesh. This growth method is potentially scalable and suitable for the production of high-performance nano-devices with well-defined nitrogen centers, to be exploited as metal-free carbon-based catalysts in several applicative fields such as electrochemistry, energy storage, gas storage/sensing or wastewater treatment.
- Published
- 2020
20. Imaging at the mesoscale
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Alessandro Sala
- Subjects
PEEM ,imaging ,mesoscale ,LEEM - Abstract
The capability to display images containing chemical, magnetic and structural information and to perform spectroscopy and diffraction from a {\mu}m-sized area makes cathode lens electron microscopy one of the most used and reliable techniques to analyze surfaces at the mesoscale. Thanks to its versatility, LEEM/PEEM systems are currently employed to study model systems in the fields of nanotechnology, nanomagnetism, material science, catalysis, energy storage, thin films and 2D materials. In the following chapter, we will present a brief but complete review of this class of instruments. After an historical digression in the introducing section, we will show first the basic operating principles of a simple setup and then the elements that can be added to improve the performances. Later, two sections will be dedicated to LEEM and PEEM respectively. In both cases, a theoretical discussion on the contrast mechanisms will prelude to a showcase of the operating modes of the instrument, with clear examples that will show the best performances available nowadays. Finally, a brief discussion about the future developments of cathode lens electron microscopy will close the chapter.
- Published
- 2020
21. What matters in implementing the factory of the future: Insights from a survey in European manufacturing regions
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Alessandro Sala, Marco Sacco, Valérie Rocchi, Andrea Zangiacomi, Elena Pessot, Cinzia Battistella, and Publica
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0209 industrial biotechnology ,Knowledge management ,Industry 4.0 ,Strategy and Management ,Supply chain ,02 engineering and technology ,Industrial and Manufacturing Engineering ,020901 industrial engineering & automation ,0502 economics and business ,Manufacturing operations ,Digitization ,Supply chain management ,Scope (project management) ,business.industry ,05 social sciences ,Digital transformation ,Computer Science Applications ,Technology implementation ,Control and Systems Engineering ,Strategic management ,business ,050203 business & management ,Software ,Qualitative research - Abstract
PurposeThis paper aims to study the extent of the transformation of European manufacturing companies towards the factory of the future (FoF) and related concepts, e.g. Industry 4.0 and digitalisation.Design/methodology/approachA qualitative survey design was used to investigate the areas, patterns and elements for implementing FoF. A total of 92 responses from manufacturing firms of Alpine regions were collected and analysed, followed by in-depth interviews with a subset of respondents to identify common challenges, drivers and opportunities for the transformation.FindingsManufacturing companies are gaining awareness on their needs and gaps in the FoF path, the implications on business strategy and the rates of innovation and technology adoption. Nevertheless, they still need to shape their organisational structures (e.g. from highly centralised to more collaborative ones) and nurture their managerial capabilities in operations and supply chain management, and customer relationships, only partially based on FoF technologies.Research limitations/implicationsThis study aims to contribute to recent literature and practice of FoF (and related concepts) by depicting a picture of the possible areas of intervention, main issues and gaps (especially in terms of skills, supply chain and customer relationships) of manufacturing companies in their digital transformation. The qualitative research design and its scope represent the main limitations.Originality/valueThis paper provides a systemic overview for FoF by encompassing the technological, strategic, managerial and organisational perspectives of digitalisation in manufacturing and integrating the insights from a multi-sectorial and multi-dimensional analysis.
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- 2020
22. Molecular anchoring stabilizes low valence Ni( i )TPP on copper against thermally induced chemical changes
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Stefania Moro, Matteo Jugovac, Alessandro Sala, Peter Puschnig, Alberto Verdini, Henning Maximilian Sturmeit, Matus Stredansky, Mirko Cinchetti, Luca Floreano, Albano Cossaro, Vitaliy Feyer, Giovanni Zamborlini, Giovanni Comelli, Iulia Cojocariu, Claus M. Schneider, Manuel Corva, Erik Vesselli, Sturmeit, H. M., Cojocariu, I., Jugovac, M., Cossaro, A., Verdini, A., Floreano, L., Sala, A., Comelli, G., Moro, S., Stredansky, M., Corva, M., Vesselli, E., Puschnig, P., Schneider, C. M., Feyer, V., Zamborlini, G., and Cinchetti, M.
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Materials science ,molecular anchoring ,Tetrapyrroles ,nickel ,oxygen ,copper ,chemistry.chemical_element ,FOS: Physical sciences ,02 engineering and technology ,Thermal treatment ,010402 general chemistry ,Photochemistry ,porphyrins ,Tetrapyrrole ,01 natural sciences ,Metal ,chemistry.chemical_compound ,Oxidation state ,Materials Chemistry ,Molecule ,Thermal stability ,ddc:530 ,Condensed Matter - Materials Science ,Valence (chemistry) ,Materials Science (cond-mat.mtrl-sci) ,General Chemistry ,Physik (inkl. Astronomie) ,021001 nanoscience & nanotechnology ,Copper ,Porphyrin ,0104 chemical sciences ,chemistry ,visual_art ,visual_art.visual_art_medium ,0210 nano-technology - Abstract
Many applications of molecular layers deposited on metal surfaces, ranging from single-atom catalysis to on-surface magnetochemistry and biosensing, rely on the use of thermal cycles to regenerate the pristine properties of the system. Thus, understanding the microscopic origin behind the thermal stability of organic/metal interfaces is fundamental for engineering reliable organic-based devices. Here, we study nickel porphyrin molecules on a copper surface as an archetypal system containing a metal center whose oxidation state can be controlled through the interaction with the metal substrate. We demonstrate that the strong molecule-surface interaction, followed by charge transfer at the interface, plays a fundamental role in the thermal stability of the layer by rigidly anchoring the porphyrin to the substrate. Upon thermal treatment, the molecules undergo an irreversible transition at 420 K, which is associated with an increase of the charge transfer from the substrate, mostly localized on the phenyl substituents, and a downward tilting of the latters without any chemical modification. This journal is
- Published
- 2020
23. Stimulated CO Dissociation and Surface Graphitization by Microfocused X-ray and Electron Beams
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Cristina Lenardi, Alessandro Sala, Andrea Locatelli, Pietro Genoni, Francesca Genuzio, B. Santos, and Tevfik Onur Menteş
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Materials science ,fungi ,food and beverages ,02 engineering and technology ,Electron ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,humanities ,Dissociation (chemistry) ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,Adsorption ,Fragmentation (mass spectrometry) ,Desorption ,Molecule ,Chemical stability ,Irradiation ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
The irradiation with photons or electrons can dramatically influence the chemical stability of a molecule, either free or adsorbed on a surface, inducing its fragmentation or desorption. We revisit here the exostimulated dissociation of CO, a prototypical case, choosing hcp thin cobalt films as model support. Intense, microfocused soft X-rays or electron beams are used to locally stimulate CO dissociation. Fast-XPS gives direct access to the adsorbates' chemical state and coverage during irradiation, enabling the kinetics of the process to be monitored in real time. The energy-dependent cross sections for photon and electron stimulated molecular dissociation and desorption are estimated for a fixed initial CO coverage of 1 / 3 ML. In the soft X-ray regime, the desorption channel always prevails over dissociation and is significantly enhanced above the O K edge. The relative dissociation probability increases steadily with increasing photon energy, reaching 30% at 780 eV. Furthermore, we show that low energy electrons in the range 50 to 200 eV dissociate CO more efficiently than X-rays. The prolonged irradiation of the Co surface in CO ambient is found to produce a continuous increase of the carbon coverage, initially promoting the formation of carbides and subsequently accumulating sp 2 carbon on the surface. Far from being a detrimental effect, the CO stimulated dissociation can be exploited to lithographically graft carbon-rich microscopic patterns on Co, with resolution well into the nanometer scale. A brief thermal treatment following irradiation results in the formation of a graphitic carbon overlayer, which effectively protects Co from oxidation upon exposure to ambient conditions, preserving its out-of-plane magnetic anisotropy and domain configuration.
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- 2018
24. Magnetic Patterning by Electron Beam-Assisted Carbon Lithography
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Andrea Locatelli, Alessandro Sala, Cristina Lenardi, Tevfik Onur Menteş, Pietro Genoni, Francesca Genuzio, and B. Santos
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010302 applied physics ,Materials science ,Magnetic domain ,Annealing (metallurgy) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Overlayer ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,Magnetization ,Magnetic anisotropy ,chemistry ,Chemical physics ,Desorption ,0103 physical sciences ,General Materials Science ,Irradiation ,0210 nano-technology ,Carbon monoxide - Abstract
We report on the proof of principle of a scalable method for writing the magnetic state by electron-stimulated molecular dissociative adsorption on ultrathin Co on Re(0001). Intense microfocused low-energy electron beams are used to promote the formation of surface carbides and graphitic carbon through the fragmentation of carbon monoxide. Upon annealing at the CO desorption temperature, carbon persists in the irradiated areas, whereas the clean surface is recovered elsewhere, giving origin to chemical patterns with nanometer-sharp edges. The accumulation of carbon is found to induce an in-plane to out-of-plane spin reorientation transition in Co, manifested by the appearance of striped magnetic domains. Irradiation at doses in excess of 1000 L of CO followed by ultrahigh vacuum annealing at 380 °C determines the formation of a graphitic overlayer in the irradiated areas, under which Co exhibits out-of-plane magnetic anisotropy. Domains with opposite magnetization are separated here by chiral Neél walls. Our fabrication protocol adds lateral control to spin reorientation transitions, permitting to tune the magnetic anisotropy within arbitrary regions of mesoscopic size. We envisage applications in the nano-engineering of graphene-spaced stacks exhibiting the desired magnetic state and properties.
- Published
- 2018
25. Quantum Confinement in Aligned Zigzag 'Pseudo‐Ribbons' Embedded in Graphene on Ni(100)
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Alessandro Sala, Cinzia Cepek, Virginia Carnevali, Zhiyu Zou, Maria Peressi, Cristina Africh, Andrea Locatelli, Giovanni Comelli, Francesca Genuzio, Tevfik Onur Menteş, Mirco Panighel, Sala, A., Zou, Z., Carnevali, V., Panighel, M., Genuzio, F., Mentes, T. O., Locatelli, A., Cepek, C., Peressi, M., Comelli, G., and Africh, C.
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Materials science ,Condensed matter physics ,1D electronic states ,Graphene ,graphene ,chemistry.chemical_element ,Condensed Matter Physics ,quantum confinement ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,nickel ,Nickel ,1D electronic state ,chemistry ,Zigzag ,law ,Quantum dot ,Electrochemistry - Abstract
Lateral quantum confinement is of great interest in tuning the electronic properties of graphene-based nanostructures, making them suitable for technological applications. In principle, these properties might be controlled through the edge topology: for example, zigzag nanoribbons are predicted to have spin-polarized edge states. The practical realization of these structures is of utmost importance in fully harnessing the electronic properties of graphene. Here, the formation of regular, 1.4 nm wide ribbon-like graphene structures with zigzag edges are reported, showing 1D electronic states. It is found that these “pseudo-ribbons” embedded in single-layer graphene supported on Ni(100) can spontaneously form upon carbon segregation underneath 1D graphene moiré domains, extending hundreds of nanometers in length. On the basis of both microscopy/spectroscopy/diffraction experiments and theoretical simulations, it is shown that these structures, even though seamlessly incorporated in a matrix of strongly interacting graphene, exhibit electronic properties closely resembling those of zigzag nanoribbons.
- Published
- 2021
26. Growth of Vanadium and Vanadium Oxide on a Rh(110) Surface
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Tevfik Onur Menteş, Bernhard von Boehn, Alessandro Sala, Ronald Imbihl, and Andrea Locatelli
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Auger electron spectroscopy ,Materials science ,Thin layers ,Analytical chemistry ,Vanadium ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Epitaxy ,01 natural sciences ,Vanadium oxide ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Metal ,General Energy ,X-ray photoelectron spectroscopy ,chemistry ,Electron diffraction ,visual_art ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
We have studied the epitaxial growth of thin layers of vanadium and vanadium oxide on a Rh(110) surface with low-energy electron diffraction (LEED), low-energy electron microscopy (LEEM), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). Up to six monolayers of V/VOx were deposited with temperatures varying between 370 and 770 K. For V deposition, (1 × n) and (n × 1) overlayers with n = 2 and 4 are observed. For the deposition of 3 MLE of VOx, a (12 × 1) structure is obtained as a stable structure. XPS of V 2p3/2 reveals the simultaneous presence of an oxidic and a metallic or strongly reduced (V2+) V component.
- Published
- 2017
27. Subfilamentary Networks Cause Cycle-to-Cycle Variability in Memristive Devices
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Andrea Locatelli, Moonsub Shim, Steven P. Rogers, Richard Valenta, Christoph Schmitz, Regina Dittmann, Christoph Baeumer, Nicolas Raab, Claus M. Schneider, Rainer Waser, Slavomír Nemšák, Alessandro Sala, Stephan Menzel, and Tevfik Onur Menteş
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010302 applied physics ,Materials science ,General Engineering ,General Physics and Astronomy ,Nanotechnology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Oxygen vacancy ,Protein filament ,Resistive switching ,0103 physical sciences ,Conductive filament ,General Materials Science ,0210 nano-technology ,Biological system - Abstract
A major obstacle for the implementation of redox-based memristive memory or logic technology is the large cycle-to-cycle and device-to-device variability. Here, we use spectromicroscopic photoemission threshold analysis and operando XAS analysis to experimentally investigate the microscopic origin of the variability. We find that some devices exhibit variations in the shape of the conductive filament or in the oxygen vacancy distribution at and around the filament. In other cases, even the location of the active filament changes from one cycle to the next. We propose that both effects originate from the coexistence of multiple (sub)filaments and that the active, current-carrying filament may change from cycle to cycle. These findings account for the observed variability in device performance and represent the scientific basis, rather than prior purely empirical engineering approaches, for developing stable memristive devices.
- Published
- 2017
28. Prothymosin-Alpha, a Novel and Sensitive Biomarker of the Inflammatory and Insulin-Resistant Statuses of Obese Individuals: A Pilot Study Involving Humans
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Marta Greco, Maria Mirabelli, Vera Tocci, Yelyzaveta Mamula, Alessandro Salatino, Francesco S. Brunetti, Francesco Dragone, Luciana Sicilia, Omar Tripolino, Eusebio Chiefari, Daniela P. Foti, and Antonio Brunetti
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prothymosin-alpha (ProT-α) ,obesity ,inflammation ,insulin resistance ,cytokines ,circulating biomarkers ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
Background: Obesity constitutes a chronic, low-grade inflammatory status that predisposes people to the development of insulin resistance and cardiometabolic complications. Hypoxia, a main pathological feature of visceral fat in obese individuals, has been shown to affect the secretome of murine 3T3-L1 adipose cells, causing the upregulation of prothymosin-alpha (ProT-α), which is a protein with immunomodulatory functions that was originally found in the thymus. The aim of this case–control observational study was to measure the circulating levels of ProT-α in obese and lean individuals and determine whether such levels are correlated with inflammatory and metabolic parameters. Methods: Sixty-one obese patients (BMI ≥ 30 Kg/m2) and fifty-one age-matched, lean controls (BMI 18.5–24.9 Kg/m2) were recruited in the Endocrinology Unit (“Mater-Domini”) of the University Hospital of Catanzaro, Italy. The exclusion criteria included affliction with acute and systemic inflammatory states (i.e., leukocytosis), recent infectious diseases or vaccinations, obesity complications (i.e., type 2 diabetes mellitus and cardiovascular diseases), hepatic or renal failure, pregnancy and lactation, cancer, use of drugs or alcohol, and smoking. Apart from routine biochemical determinations, serum samples were screened for the presence of ProT-α using an ELISA method and for the presence of a panel of inflammatory cytokines and growth factors via a multiparametric chemiluminescence micro-array. Results: Between the age-matched groups, no statistically significant differences were shown in relation to fasting glucose, HbA1c, liver function tests, lipid profiles, circulating interleukins (IL)-1α, -1β, -2, -4, -8, and -10, MCP-1, TNF-α, VEGF and EGF. Instead, significantly higher median levels were observed in obese patients vs. lean controls with respect to fasting insulin levels (p < 0.001), a classic insulin resistance marker, and IL-6 (p = 0.004). In addition, ProT-α levels were significantly and considerably higher in obese patients compared to lean controls (median ProT-α, 600.0 vs. 411.5 pg/mL, p = 0.004) and showed a moderate to strong positive relationship with fasting insulin levels and selected cytokines (i.e., TNF-α and IL-8). Conclusions: An increase in circulating levels of ProT-α is linked with obesity and can be detected before any clinical cardiometabolic complications develop. ProT-α may represent a novel and sensitive biomarker for inflammation and insulin resistance in obese individuals.
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- 2023
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29. Optical trapping of sub-millimeter sized particles and microorganisms
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Laurynas Lialys, Justinas Lialys, Alessandro Salandrino, Brian D. Ackley, and Shima Fardad
- Subjects
Medicine ,Science - Abstract
Abstract While optical tweezers (OT) are mostly used for confining smaller size particles, the counter-propagating (CP) dual-beam traps have been a versatile method for confining both small and larger size particles including biological specimen. However, CP traps are complex sensitive systems, requiring tedious alignment to achieve perfect symmetry with rather low trapping stiffness values compared to OT. Moreover, due to their relatively weak forces, CP traps are limited in the size of particles they can confine which is about 100 μm. In this paper, a new class of counter-propagating optical tweezers with a broken symmetry is discussed and experimentally demonstrated to trap and manipulate larger than 100 μm particles inside liquid media. Our technique exploits a single Gaussian beam folding back on itself in an asymmetrical fashion forming a CP trap capable of confining small and significantly larger particles (up to 250 μm in diameter) based on optical forces only. Such optical trapping of large-size specimen to the best of our knowledge has not been demonstrated before. The broken symmetry of the trap combined with the retro-reflection of the beam has not only significantly simplified the alignment of the system, but also made it robust to slight misalignments and enhances the trapping stiffness as shown later. Moreover, our proposed trapping method is quite versatile as it allows for trapping and translating of a wide variety of particle sizes and shapes, ranging from one micron up to a few hundred of microns including microorganisms, using very low laser powers and numerical aperture optics. This in turn, permits the integration of a wide range of spectroscopy techniques for imaging and studying the optically trapped specimen. As an example, we will demonstrate how this novel technique enables simultaneous 3D trapping and light-sheet microscopy of C. elegans worms with up to 450 µm length.
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- 2023
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30. Spillover Reoxidation of Ceria Nanoparticles
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Andrea Locatelli, Christopher A. Muryn, David C. Grinter, Chi L. Pang, Geoff Thornton, Tevfik Onur Menteş, Alessandro Sala, and Chi Ming Yim
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Low-energy electron diffraction ,Chemistry ,Analytical chemistry ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Partial pressure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Heterogeneous catalysis ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Low-energy electron microscopy ,Photoemission electron microscopy ,General Energy ,X-ray photoelectron spectroscopy ,Physical and Theoretical Chemistry ,0210 nano-technology ,Superstructure (condensed matter) - Abstract
Interest in resolving the mechanisms behind ceria’s activity has been intense due to the numerous industrial applications including those in heterogeneous catalysis. In this work, we study the reduction and reoxidation of ultrathin CeO2(111) nanoislands on Rh(111) and Pt(111) substrates, so-called inverse model catalysts, with a combination of real and reciprocal space techniques based on X-ray photoemission electron microscopy (XPEEM) and low energy electron microscopy. Soft X-ray microfocused illumination was employed to reduce the ceria islands, which we are able to control by varying the oxygen partial pressure within the measurement chamber. Low energy electron diffraction measurements of the irradiated ceria films demonstrate the formation of an ordered array of oxygen vacancies leading to a (√7 × √7)R19.1° superstructure attributed to the ι-phase (Ce7O12)(111). Resonant photoelectron spectroscopy provides the required high sensitivity to detect small changes in Ce3+ concentration. The high spatial ...
- Published
- 2016
31. Novel insights into the pharmacological modulation of human periodontal ligament stem cells by the amino-bisphosphonate Alendronate
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Anna Di Vito, Emanuela Chiarella, Jessica Sovereto, Jessica Bria, Ida Daniela Perrotta, Alessandro Salatino, Francesco Baudi, Alessandro Sacco, Alessandro Antonelli, Flavia Biamonte, Tullio Barni, and Amerigo Giudice
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Alendronate ,Human periodontal ligament mesenchymal stem cells ,Oxidative stress ,Osteogenic differentiation ,Cytology ,QH573-671 - Abstract
Alendronate (ALN) is a second-generation bisphosphonate widely used for osteoporosis and cancer-induced bone lesions. Many studies have confirmed a strong relationship between osteonecrosis of the jaws (ONJ) development and oral bisphosphonates, especially ALN, although the molecular mechanisms underlying this pathology have not yet been elucidated. The reduction in bone turnover and vascularization usually observed in ONJ are the result of ALN action on different cell types harboured in oral microenvironment, such as osteoclasts, endothelial cells, and periodontal ligament stem cells (PDLSCs). In this perspective, the present study aims to investigate the effects of different ALN concentrations (2 μM, 5 μM, 10 μM, 25 μM, 50 μM) on the phenotype and functional properties of human PDLSCs (hPDLSCs). hPDLSCs showed a decrease in cell viability (MTT assay) only when treated with ALN concentration of 10 μM or larger for 48 h and 72 h. Cell cycle analysis revealed a moderate increase in proportion of S-phase cells after exposure to low ALN concentration (2–5 μM), an effect that was reverted after exposure to 10–50 μM ALN. Conversely, cell death was evidenced via Annexin V/PI assay at very high concentration of ALN (50 μM) after 4 days of treatment. In addition, we explored whether the effects of ALN on hPDLSCs growth and survival can be mediated by its ability to modulate oxidative stress. To this, we quantified the intracellular ROS amount and lipid peroxidation by using DCF probe and Bodipy staining, respectively. Flow cytometry analysis showed that ALN induced a dose-dependent reduction of intracellular oxidative stress and lipid peroxidation upon treatment with low concentrations at both 48 h and 72 h. Increased levels of oxidative stress was reported at 50 μM ALN and was also confirmed via TEM analysis. Despite the stability of the cellular immunophenotype, hPDLSCs showed impaired mobility after ALN exposure. Chronic exposure (7–14 days) to ALN in the range of 2–10 μM significantly decreased the expression of the differentiation-related factors ALP, RUNX2, COLI, and OPN as well as the osteogenic ability of hPDLSCs compared with untreated cells. Conversely, higher doses were found to be neutral. Our findings indicated that the effects of ALN on hPDLSCs behavior are dose-dependent and suggest a role for oxidative stress in ALN-induced cell death that may lead to novel therapeutic approaches for ONJ.
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- 2023
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32. Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures
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Stefania Pizzini, Gilles Gaudin, Stéphane Auffret, Hongxin Yang, Jan Vogel, Alessandro Sala, Michael Foerster, Liliana D. Buda-Prejbeanu, Ioan Mihai Miron, Olivier Boulle, Lucia Aballe, Mohamed Belmeguenai, S. M. Chérif, Dayane de Souza Chaves, Andrea Locatelli, Olivier Klein, Mairbek Chshiev, Yves Roussigné, Andrey Stashkevich, Tevfik Onur Menteş, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Elettra Sincrotrone Trieste, Laboratoire des Sciences des Procédés et des Matériaux (LSPM), Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Cité (USPC)-Institut Galilée-Université Paris 13 (UP13), ALBA Synchrotron light source [Barcelone], ANR-14-CE26-0012,ULTRASKY,Skyrmions dans les couches magnétiques ultraminces en vue d'une spintronique basse consommation(2014), Micro et NanoMagnétisme (NEEL - MNM), and Université Paris 13 (UP13)-Institut Galilée-Université Sorbonne Paris Cité (USPC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Nanostructure ,Dzyaloshinskii - Moriya interaction ,Biomedical Engineering ,FOS: Physical sciences ,Bioengineering ,02 engineering and technology ,Magnetic skyrmion ,01 natural sciences ,Condensed Matter::Materials Science ,Magnetization ,Spin wave ,0103 physical sciences ,Perpendicular Magnetic Anisotropy ,General Materials Science ,Electrical and Electronic Engineering ,010306 general physics ,[PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall] ,Physics ,Condensed Matter - Materials Science ,Condensed matter physics ,Spintronics ,Magnetic circular dichroism ,Skyrmion ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Magnetic field ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,0210 nano-technology - Abstract
Magnetic skyrmions are chiral spin structures with a whirling configuration. Their topological properties, nanometer size and the fact that they can be moved by small current densities have opened a new paradigm for the manipulation of magnetisation at the nanoscale. To date, chiral skyrmion structures have been experimentally demonstrated only in bulk materials and in epitaxial ultrathin films and under external magnetic field or at low temperature. Here, we report on the observation of stable skyrmions in sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero applied magnetic field. We use high lateral resolution X-ray magnetic circular dichroism microscopy to image their chiral N\'eel internal structure which we explain as due to the large strength of the Dzyaloshinskii-Moriya interaction as revealed by spin wave spectroscopy measurements. Our results are substantiated by micromagnetic simulations and numerical models, which allow the identification of the physical mechanisms governing the size and stability of the skyrmions., Comment: Submitted version. Extended version to appear in Nature Nanotechnology
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- 2016
33. Formation of a Quasi-Free-Standing Single Layer of Graphene and Hexagonal Boron Nitride on Pt(111) by a Single Molecular Precursor
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Tevfik Onur Menteş, Stefano Agnoli, Mattia Cattelan, Federica Bondino, Alessandro Sala, Silvia Nappini, Igor Píš, and Elena Magnano
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ADSORPTION ,Materials science ,Chemical substance ,Hexagonal Boron Nitride ,LEVEL ,Hexagonal boron nitride ,Nanotechnology ,02 engineering and technology ,Molecular precursor ,010402 general chemistry ,01 natural sciences ,law.invention ,CARBON ,Biomaterials ,Magazine ,law ,HETEROSTRUCTURES ,Electrochemistry ,h-BN ,Plasmon ,Graphene ,graphene ,h-boron nitride ,x-ray photoelectron spectroscopy ,x-ray absorption ,2D materials ,in-plane heterostructures ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,DOPED GRAPHENE ,ATOMIC LAYERS ,NITROGEN ,INTERFACE ,GROWTH ,CO ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Crystallography ,quasi-free standing ,0210 nano-technology ,Science, technology and society ,Single layer - Abstract
It is shown that on Pt(111) it is possible to prepare hexagonal boron nitride (h-BN) and graphene (G) in-plane heterojunctions from a single molecular precursor, by thermal decomposition of dimethylamine borane (DMAB). Photoemission, near-edge X-ray absorption spectroscopy, low energy electron microscopy, and temperature programmed desorption measurements indicate that the layer fully covers the Pt(111) surface. Evidence of in-plane layer continuity and weak interaction with Pt substrate has been established. The findings demonstrate that dehydrogenation and pyrolitic decomposition of DMAB is an efficient and easy method for obtaining a continuous almost freestanding layer mostly made of G, h-BN with only a low percentage (h-BN or boron carbonitride, BCN at the boundaries) in the same 2D sheet on a metal substrate, such as Pt(111), paving the way for the advancement of next-generation G-like-based electronics and novel spintronic devices.
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- 2015
34. Small and Medium Enterprises collaborations with knowledge intensive services: an explorative analysis of the impact of innovation vouchers
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Alessandro Sala, Roberto Verganti, and Paolo Landoni
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Voucher ,Management of Technology and Innovation ,Strategy and Management ,0502 economics and business ,05 social sciences ,Small and medium-sized enterprises ,Business ,0509 other social sciences ,Business and International Management ,Marketing ,050905 science studies ,General Business, Management and Accounting ,050203 business & management - Abstract
This study analyses the effects and dynamics behind a new type of innovation policy for Small and Medium Enterprises (SMEs): innovation vouchers. This policy is aimed at encouraging SMEs to collaborate with universities and with organisations offering Knowledge Intensive Services. Despite its innovativeness and growing diffusion, the innovation voucher has received only limited attention in the literature. After reviewing the literature on R&D collaborations and innovation vouchers, the article conducts in-depth analysis on two innovation voucher programs in the Lombardy region (Italy). The analysis is based on seven case studies of SMEs that have benefitted from this policy. The results highlight how innovation vouchers have influenced the development of innovation projects and technological collaboration in SMEs. The article concludes with discussion on the effectiveness of the voucher policy, its limitations and policy implications.
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- 2015
35. Flux-closure domains in high aspect ratio electroless-deposited CoNiB nanotubes
- Author
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Eric Gautier, Laurent Cagnon, Michal Staňo, B. Trapp, Maxime Rioult, Rachid Belkhou, Wolfgang Ensinger, Jean-Christophe Toussaint, Sandra Schaefer, Alessandro Sala, Tevfik Onur Menteş, Sebastian Bochmann, Andrea Locatelli, Sylvain Martin, Olivier Fruchart, Alexis Wartelle, Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Department of Materials Science, Darmstadt University of Technology [Darmstadt], Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Elettra Sincrotrone Trieste, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), LOEWE project RESPONSE of the Hessen State Ministry of Higher Education, Research and the Arts (HMWK), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), and Micro et NanoMagnétisme (NEEL - MNM)
- Subjects
Condensed Matter - Materials Science ,Materials science ,Condensed Matter - Mesoscale and Nanoscale Physics ,Magnetic domain ,Condensed matter physics ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Flux ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Grain size ,lcsh:QC1-999 ,Magnetic anisotropy ,Magnetization ,Magnetic Phenomena ,Ferromagnetism ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,010306 general physics ,0210 nano-technology ,Anisotropy ,lcsh:Physics - Abstract
We report the imaging of magnetic domains in ferromagnetic CoNiB nanotubes with very long aspect ratio, fabricated by electroless plating. While axial magnetization is expected for long tubes made of soft magnetic materials, we evidence series of azimuthal domains. We tentatively explain these by the interplay of anisotropic strain and/or grain size, with magneto-elasticity and/or anisotropic interfacial magnetic anisotropy. This material could be interesting for dense data storage, as well as curvature-induced magnetic phenomena such as the non-reciprocity of spin-wave propagation., Comment: Focus only on azimuthal domains, information on domain walls (part of v1) removed - title, abstract and discussion changed accordingly, tubular racetracks scheme removed; new references, figures. Submission to SciPost (reformatted, new abstract, DOI added to references). Enhanced discussion of anisotropy, disagreement of synchrotron data and magnetometry rectified, new MOKE data added
- Published
- 2018
36. Bloch-point-mediated topological transformations of magnetic domain walls in cylindrical nanowires
- Author
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Andrea Locatelli, Michael Foerster, Lucia Aballe, B. Trapp, Olivier Fruchart, Jean-Christophe Toussaint, Julien Bachmann, Alexis Wartelle, T. O. Menteş, C. Thirion, Laurent Cagnon, Michal Staňo, Alessandro Sala, Sebastian Bochmann, Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Saint-Petersburg State University, ALBA Synchrotron light source [Barcelone], Elettra Sincrotrone Trieste, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), European Project: 309589,EC:FP7:NMP,FP7-NMP-2012-SMALL-6,M3D(2012), Micro et NanoMagnétisme (NEEL - MNM), and Saint Petersburg State University (SPBU)
- Subjects
Field (physics) ,Magnetic domain ,Nucleation ,Nanowire ,FOS: Physical sciences ,02 engineering and technology ,STRIPS ,Topology ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,Singularity ,law ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Bloch point ,010306 general physics ,Topology (chemistry) ,Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics ,Materials Science (cond-mat.mtrl-sci) ,Magnetic domain wall ,021001 nanoscience & nanotechnology ,Transformation (function) ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,0210 nano-technology - Abstract
International audience; Cylindrical nanowires made of soft magnetic materials, in contrast to thin strips, may host domain walls of two distinct topologies. Unexpectedly, we evidence experimentally the dynamic transformation of topology upon wall motion above a field threshold. Micromagnetic simulations highlight the underlying precessional dynamics for one way of the transformation, involving the nucleation of a Bloch-point singularity, however, fail to reproduce the reverse process. This rare discrepancy between micromagnetic simulations and experiments raises fascinating questions in material and computer science.
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- 2018
37. Magnetic skyrmions in confined geometries: Effect of the magnetic field and the disorder
- Author
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Michael Foerster, Sarnjeet S. Dhesi, Eric Gautier, Gilles Gaudin, Alessandro Sala, Liliana D. Buda-Prejbeanu, Tevfik Onur Menteş, Lucia Aballe, Soong-Geun Je, Dayane de Souza Chaves, Jan Vogel, Andrea Locatelli, Stefania Pizzini, Stéphane Auffret, Olivier Boulle, Roméo Juge, Francesco Maccherozzi, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ALBA Synchrotron light source [Barcelone], Elettra Sincrotrone Trieste, IRER - Istituto Regionale di Ricerca della Lombardia, DIAMOND Light source, and Micro et NanoMagnétisme (NEEL - MNM)
- Subjects
Nanostructure ,FOS: Physical sciences ,02 engineering and technology ,Magnetic skyrmion ,01 natural sciences ,Condensed Matter::Materials Science ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Thin film ,010306 general physics ,Anisotropy ,ComputingMilieux_MISCELLANEOUS ,Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed matter physics ,Skyrmion ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Amplitude ,[PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other] ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Nanodot ,0210 nano-technology - Abstract
We report on the effect of the lateral confinement and a perpendicular magnetic field on isolated room-temperature magnetic skyrmions in sputtered Pt/Co/MgO nanotracks and nanodots. We show that the skyrmions size can be easily tuned by playing on the lateral dimensions of the nanostructures and by using external magnetic field amplitudes of a few mT, which allow to reach sub-100 nm diameters. Our XMCD-PEEM observations also highlight the important role of the pinning on the skyrmions size and stability under an out-of-plane magnetic field. Micromagnetic simulations reveal that the effect of local pinning can be well accounted for by considering the thin film grain structure with local anisotropy variations and reproduce well the dependence of the skyrmion diameter on the magnetic field and the geometry., Comment: 17 pages, 4 figures
- Published
- 2018
38. Fe intercalation under graphene and hexagonal boron nitride in-plane heterostructure on Pt(111)
- Author
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Silvia Nappini, Tevfik Onur Menteş, Alessandro Sala, Igor Píš, Federica Bondino, Elena Magnano, and Andrea Locatelli
- Subjects
Materials science ,Diffusion ,Intercalation (chemistry) ,chemistry.chemical_element ,FOS: Physical sciences ,Hexagonal boron nitride ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Oxygen ,law.invention ,law ,Physics - Chemical Physics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,General Materials Science ,Chemical Physics (physics.chem-ph) ,Condensed Matter - Mesoscale and Nanoscale Physics ,Spintronics ,Graphene ,Heterojunction ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Ferromagnetism ,Chemical engineering ,chemistry ,0210 nano-technology - Abstract
Metal nanostructures confined between sp2 hybridized 2D materials and solid supports are attracting attention for their potential application in new nanotechnologies. Model studies under well-defined conditions are valuable for understanding the fundamental aspects of the phenomena under 2D covers. In this work we investigate the intercalation of iron atoms through a single layer of mixed graphene and hexagonal boron nitride on Pt(111) using a combination of spectroscopic and microscopic techniques. Thermally activated diffusion of iron proceeds preferentially under graphene and only partially under hexagonal boron nitride areas. When oxygen is coadsorbed with iron, the intercalation rate is higher, and formation of B2O3 and oxygenated B-C species is observed. Our results suggest the possibility of confining ferromagnetic layers under heterostructures of graphene and hexagonal boron nitride with potential technological implications in the fields of spintronics, magnetic data storage or chemistry under 2D covers. © 2018 Elsevier Ltd
- Published
- 2018
39. Reactive Phase Separation during Methanol Oxidation on a V-Oxide-Promoted Rh(110) Surface
- Author
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Tevfik Onur Menteş, Andrea Locatelli, Bernhard von Boehn, Alessandro Sala, and Ronald Imbihl
- Subjects
Materials science ,oxidation ,Binding energy ,Analytical chemistry ,Oxide ,Phase separation ,02 engineering and technology ,01 natural sciences ,Vanadium oxide ,Catalysis ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,Phase (matter) ,0103 physical sciences ,Monolayer ,Surface layer ,Physical and Theoretical Chemistry ,010306 general physics ,Oxides ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Oxygen ,General Energy ,chemistry ,0210 nano-technology ,Layers - Abstract
The distribution of ultrathin layers of vanadium oxide on Rh(110) (theta(V)
- Published
- 2018
- Full Text
- View/download PDF
40. Graphene on nickel (100) micrograins: Modulating the interface interaction by extended moiré superstructures
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Cinzia Cepek, Marcelo M. Mariscal, Zhiyu Zou, Mirco Panighel, Cristina Africh, Virginia Carnevali, Alessandro Sala, Giovanni Comelli, Maria Peressi, Laerte L. Patera, Matteo Jugovac, German Soldano, Zou, Zhiyu, Carnevali, Virginia, Jugovac, Matteo, Patera, Laerte L., Sala, Alessandro, Panighel, Mirco, Cepek, Cinzia, Soldano, German, Mariscal, Marcelo M., Peressi, Maria, Comelli, Giovanni, and Africh, Cristina
- Subjects
Materials science ,MOIRÉ SUPERSTRUCTURES ,Misorientation ,GRAPHENE ON POLYCRYSTALLINE NICKEL ,moire' superstructures ,02 engineering and technology ,Substrate (electronics) ,Chemical vapor deposition ,01 natural sciences ,nickel surface ,law.invention ,numerical simulations ,purl.org/becyt/ford/1 [https] ,Transition metal ,law ,CHEMICAL VAPOR DEPOSITION ,0103 physical sciences ,purl.org/becyt/ford/1.4 [https] ,General Materials Science ,DENSITY FUNCTIONAL THEORY ,graphene ,scanning tunneling microscopy ,010306 general physics ,Graphene ,Otras Ciencias Químicas ,Ciencias Químicas ,General Chemistry ,021001 nanoscience & nanotechnology ,Graphene | Chemical vapor deposition | graphene synthesis ,Chemical physics ,Crystallite ,Scanning tunneling microscope ,0210 nano-technology ,Single crystal ,CIENCIAS NATURALES Y EXACTAS ,moire' superstructure - Abstract
Interaction with the substrate strongly affects the electronic/chemical properties of supported graphene. So far, graphene grown by chemical vapor deposition (CVD) on catalytic single crystal transition metal surfaces - mostly 3-fold close-packed - has mainly been studied. Herein, we investigated CVD graphene on a polycrystalline nickel (Ni) substrate, focusing in particular on (100) micrograins and comparing the observed behavior with that on single crystal Ni(100) substrate. The symmetry-mismatch leads to moiré superstructures with stripe-like or rhombic-network morphology, which were characterized by atomically-resolved scanning tunneling microscopy (STM). Density functional theory (DFT) simulations shed light on spatial corrugation and interfacial interactions: depending on the misorientation angle, graphene is either alternately physi- and chemisorbed or uniformly chemisorbed, the interaction being modulated by the (sub)nanometer-sized moiré superstructures. Ni(100) micrograins appear to be a promising substrate to finely tailor the electronic properties of graphene at the nanoscale, with relevant perspective applications in electronics and catalysis. Fil: Zou, Zhiyu. The Abdus Salam. International Centre for Theoretical Physics; Italia Fil: Carnevali, Virginia. Università degli Studi di Trieste; Italia Fil: Jugovac, Matteo. Università degli Studi di Trieste; Italia. Helmholtz Gemeinschaft. Forschungszentrum Jülich; Alemania. The Abdus Salam. International Centre for Theoretical Physics; Italia Fil: Patera, Laerte L.. Helmholtz Gemeinschaft. Forschungszentrum Jülich; Alemania. Vienna University of Technology; Austria Fil: Sala, Alessandro. Università degli Studi di Trieste; Italia Fil: Panighel, Mirco. Helmholtz Gemeinschaft. Forschungszentrum Jülich; Alemania. Università degli Studi di Trieste; Italia Fil: Cepek, Cinzia. Università degli Studi di Trieste; Italia Fil: Soldano, Germán. Helmholtz Gemeinschaft. Forschungszentrum Jülich; Alemania Fil: Mariscal, Marcelo. Università degli Studi di Trieste; Italia Fil: Peressi, Maria. Universitat Regensburg; Alemania Fil: Comelli, Giovanni. Laboratorio Nazionale Tasc; Fil: Africh, Cristina. Università degli Studi di Trieste; Italia
- Published
- 2018
41. Nanobubbles at GPa Pressure under Graphene
- Author
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Andrea Locatelli, N. Stojić, Giovanni Comelli, Cristina Africh, Mighfar Imam, Giovanni Zamborlini, Alessandro Sala, Nadia Binggeli, Tevfik Onur Menteş, Laerte L. Patera, Zamborlini, Giovanni, Imam, Mighfar, Patera, LAERTE LUIGI, Menteş, Tevfik Onur, Stojić, Nataša, Africh, Cristina, Sala, Alessandro, Binggeli, Nadia, Comelli, Giovanni, and Locatelli, Andrea
- Subjects
Materials science ,Annealing (metallurgy) ,chemistry.chemical_element ,Bioengineering ,Nanotechnology ,Condensed Matter Physic ,Thermal treatment ,Ion ,law.invention ,law ,Ab initio quantum chemistry methods ,implantation ,General Materials Science ,Irradiation ,ion-irradiation ,Argon ,Graphene ,Mechanical Engineering ,Chemistry (all) ,General Chemistry ,Condensed Matter Physics ,ripening ,nanobubble ,chemistry ,Chemical physics ,argon ,Nanometre ,Materials Science (all) ,nanobubbles - Abstract
We provide direct evidence that irradiation of a graphene membrane on Ir with low-energy Ar ions induces formation of solid noble-gas nanobubbles. Their size can be controlled by thermal treatment, reaching tens of nanometers laterally and height of 1.5 nm upon annealing at 1080 °C. Ab initio calculations show that Ar nanobubbles are subject to pressures reaching tens of GPa, their formation being driven by minimization of the energy cost of film distortion and loss of adhesion.
- Published
- 2015
42. Phase Coexistence in Two-Dimensional Fe0.70Ni0.30 Films on W(110)
- Author
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Elio Vescovo, M. A. Niño, Andrea Locatelli, Tevfik Onur Menteş, Alessandro Sala, and J. M. Ablett
- Subjects
Morphology (linguistics) ,Materials science ,Alloy ,chemistry.chemical_element ,Bioengineering ,Surfaces and Interfaces ,Surface finish ,engineering.material ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Crystallography ,Nickel ,chemistry ,Mechanics of Materials ,Phase (matter) ,engineering ,Surface structure ,Biotechnology - Published
- 2015
43. Corrigendum: Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures
- Author
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Michael Foerster, Tevfik Onur Menteş, Ioan Mihai Miron, Stefania Pizzini, Stéphane Auffret, Liliana D. Buda-Prejbeanu, Yves Roussigné, Olivier Boulle, Jan Vogel, Gilles Gaudin, S. M. Chérif, Hongxin Yang, Andrey Stashkevich, Mohamed Belmeguenai, Dayane de Souza Chaves, Andrea Locatelli, Alessandro Sala, Lucia Aballe, Mairbek Chshiev, and Olivier Klein
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Nanostructure ,Materials science ,Condensed matter physics ,Skyrmion ,Biomedical Engineering ,Bioengineering ,02 engineering and technology ,Flory–Huggins solution theory ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Ab initio quantum chemistry methods ,0103 physical sciences ,Monolayer ,General Materials Science ,Electrical and Electronic Engineering ,010306 general physics ,0210 nano-technology - Abstract
Nature Nanotechnology 11, 449–454 (2016); published online 25 January 2016; corrected after print 18 July 2017 In the version of this Article originally published, the Dzyaloshinskii–Moriya interaction parameter, D, should have been multiplied by √3. The vertical scale of Fig. 2 has been updated accordingly as has the following sentence concerning D values: “For 5 monolayers (ML) of Co, equivalent to a total Co thickness of 1 nm, the ab initio calculations predict = 4.
- Published
- 2017
44. Electronic properties of single-layer tungsten disulfide on epitaxial graphene on silicon carbide
- Author
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Stefan Link, Tevfik Onur Menteş, Camilla Coletti, Stiven Forti, Holger Büch, Alessandro Sala, Ulrich Starke, Antonio Rossi, Andrea Locatelli, Tommaso Cavallucci, Kathrin Müller, Michele Magnozzi, Maurizio Canepa, Valentina Tozzini, and Francesco Bisio
- Subjects
Electronic structure ,Materials science ,Tungsten disulfide ,02 engineering and technology ,01 natural sciences ,7. Clean energy ,Molecular physics ,law.invention ,chemistry.chemical_compound ,law ,0103 physical sciences ,Monolayer ,General Materials Science ,Work function ,010306 general physics ,Electronic band structure ,Graphene ,021001 nanoscience & nanotechnology ,Tungsten Disulfide ,Crystallography ,Photoemission electron microscopy ,Electron diffraction ,chemistry ,Density functional theory ,Materials Science (all) ,0210 nano-technology - Abstract
This work reports an electronic and micro-structural study of an appealing system for optoelectronics: tungsten disulfide (WS2) on epitaxial graphene (EG) on SiC(0001). The WS2 is grown via chemical vapor deposition (CVD) onto the EG. Low-energy electron diffraction (LEED) measurements assign the zero-degree orientation as the preferential azimuthal alignment for WS2/EG. The valence-band (VB) structure emerging from this alignment is investigated by means of photoelectron spectroscopy measurements, with both high space and energy resolution. We find that the spin–orbit splitting of monolayer WS2 on graphene is of 462 meV, larger than what is reported to date for other substrates. We determine the value of the work function for the WS2/EG to be 4.5 ± 0.1 eV. A large shift of the WS2 VB maximum is observed as well, due to the lowering of the WS2 work function caused by the donor-like interfacial states of EG. Density functional theory (DFT) calculations carried out on a coincidence supercell confirm the experimental band structure to an excellent degree. X-ray photoemission electron microscopy (XPEEM) measurements performed on single WS2 crystals confirm the van der Waals nature of the interface coupling between the two layers. In virtue of its band alignment and large spin–orbit splitting, this system gains strong appeal for optical spin-injection experiments and opto-spintronic applications in general.
- Published
- 2017
45. Cathode lens spectromicroscopy: methodology and applications
- Author
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Alessandro Sala, T. O. Menteş, Andrea Locatelli, and Giovanni Zamborlini
- Subjects
Materials science ,Magnetism ,General Physics and Astronomy ,Nanotechnology ,Electronic structure ,Electron ,Review ,X-ray magnetic circular dichroism (XMCD) ,lcsh:Chemical technology ,lcsh:Technology ,law.invention ,Condensed Matter::Materials Science ,law ,intercalation ,Monolayer ,nanostructures ,General Materials Science ,lcsh:TP1-1185 ,Electrical and Electronic Engineering ,lcsh:Science ,Mesoscopic physics ,Graphene ,X-ray photoemission electron microscopy (XPEEM) ,lcsh:T ,graphene ,Synchrotron ,lcsh:QC1-999 ,Characterization (materials science) ,Nanoscience ,magnetism ,lcsh:Q ,ddc:620 ,low-energy electron microscopy (LEEM) ,gold (Au) ,lcsh:Physics - Abstract
The implementation of imaging techniques with low-energy electrons at synchrotron laboratories allowed for significant advancement in the field of spectromicroscopy. The spectroscopic photoemission and low energy electron microscope, SPELEEM, is a notable example. We summarize the multitechnique capabilities of the SPELEEM instrument, reporting on the instrumental aspects and the latest developments on the technical side. We briefly review applications, which are grouped into two main scientific fields. The first one covers different aspects of graphene physics. In particular, we highlight the recent work on graphene/Ir(100). Here, SPELEEM was employed to monitor the changes in the electronic structure that occur for different film morphologies and during the intercalation of Au. The Au monolayer, which creeps under graphene from the film edges, efficiently decouples the graphene from the substrate lowering the Dirac energy from 0.42 eV to 0.1 eV. The second field combines magnetism studies at the mesoscopic length scale with self-organized systems featuring ordered nanostructures. This example highlights the possibility to monitor growth processes in real time and combine chemical characterization with X-ray magnetic circular dichroism–photoemission electron microscopy (XMCD–PEEM) magnetic imaging by using the variable photon polarization and energy available at the synchrotron source.
- Published
- 2014
46. Interconversion of α-Fe2O3 and Fe3O4 Thin Films: Mechanisms, Morphology, and Evidence for Unexpected Substrate Participation
- Author
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Dietrich Menzel, Francesca Genuzio, Alessandro Sala, Thomas Schmidt, and Hans-Joachim Freund
- Subjects
Materials science ,Morphology (linguistics) ,Substrate (chemistry) ,Hematite ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Crystallography ,General Energy ,Low energy ,chemistry ,visual_art ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry ,Thin film ,Magnetite - Abstract
The reversible transformations of thin magnetite (Fe3O4) and hematite (α-Fe2O3) films grown on Pt(111) and Ag(111) single crystals as support have been investigated by a combined low energy electro...
- Published
- 2014
47. The Initial ATA Risk Classification, but Not the AJCC/TNM Stage, Predicts the Persistence or Relapse of Differentiated Thyroid Cancer in Long-Term Surveillance
- Author
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Stefania Giuliano, Maria Mirabelli, Eusebio Chiefari, Vera Tocci, Alessandra Donnici, Stefano Iuliano, Alessandro Salatino, Daniela Patrizia Foti, Antonio Aversa, and Antonio Brunetti
- Subjects
differentiated thyroid cancer ,prognostic factors ,AJCC/TNM stage ,ATA classification ,radioiodine ,Diseases of the endocrine glands. Clinical endocrinology ,RC648-665 - Abstract
Background: The American Joint Commission on Cancer on Tumor Node Metastasis (AJCC/TNM) staging system provides adequate information on the risk of differentiated thyroid cancer (DTC)-specific mortality in totally thyroidectomized patients, but its role in predicting persistence and relapse of disease is uncertain. The relatively new 2015 American Thyroid Association (ATA) guidelines recommend stratifying patients at the time of DTC diagnosis with its own risk classification system, in order to identify those at high risk of residual or recurrent morbidity who may benefit from post-operative radioiodine (RAI) administration and/or need additional work-up. Methods: To verify the prevalence proportion of persistence or relapse of disease, a consecutive cohort of 152 patients with a diagnosis of DTC, subjected to total thyroidectomy (+/− post-operative RAI administration as per guidelines indication) and to neck ultrasonography (US), as well as biochemical surveillance for a minimum of 2 years at the Endocrinology Unit of Mater-Domini Hospital (Catanzaro, Italy), was enrolled. The prognostic role of the AJCC/TNM stage and ATA risk classification system was analyzed by logistic regression. Results: At a mean of 9 years after surgical treatment, DTC was found to persist or relapse in 19 (12.5%) participants. The initial risk for these outcomes, based on the ATA classification, was mostly low (53.9%) or intermediate (39.5%). AJCC/TNM stages were predominantly stage I or stage II. Despite a small representation in this cohort, high-risk patients according to the ATA classification had 8-fold higher odds of persistence or relapse of disease than those of low-risk participants, while controlling for potential risk modifiers, including age at DTC diagnosis, male gender, and post-operative RAI administration (p = 0.008). In contrast, the AJCC/TNM stage was not associated with the disease status at the last follow-up visit (p = 0.068 for the 7th Edition; p = 0.165 for the 8th Edition). Furthermore, low-risk participants subjected to post-operative RAI administration had the same probability of persistence or relapse of DTC when compared to those who had undergone total thyroidectomy only. Conclusions: There is a need for the endocrine community to revise the current work-up of DTC. The initial ATA risk classification is a reliable tool for predicting the persistence or relapse of disease in long-term surveillance.
- Published
- 2022
- Full Text
- View/download PDF
48. First experimental proof for aberration correction in XPEEM: Resolution, transmission enhancement, and limitation by space charge effects
- Author
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Hans-Joachim Freund, Helder Marchetto, Thomas Schmidt, Alessandro Sala, and Eberhard Umbach
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Chemistry ,business.industry ,Aperture ,Resolution (electron density) ,Electron ,Kinetic energy ,Space charge ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optical axis ,Low-energy electron microscopy ,Optics ,X-ray photoelectron spectroscopy ,business ,Instrumentation - Abstract
The positive effect of double aberration correction in x-ray induced Photoelectron Emission Microscopy (XPEEM) has been successfully demonstrated for both, the lateral resolution and the transmission, using the Au 4f XPS peak for element specific imaging at a kinetic energy of 113 eV. The lateral resolution is improved by a factor of four, compared to a non-corrected system, whereas the transmission is enhanced by a factor of 5 at a moderate resolution of 80 nm. With an optimized system setting, a lateral resolution of 18 nm could be achieved, which is up to now the best value reported for energy filtered XPEEM imaging. However, the absolute resolution does not yet reach the theoretical limit of 2 nm, which is due to space charge limitation. This occurs along the entire optical axis up to the contrast aperture. In XPEEM the pulsed time structure of the exciting soft x-ray light source causes a short and highly intense electron pulse, which results in an image blurring. In contrast, the imaging with elastically reflected electrons in the low energy electron microscopy (LEEM) mode yields a resolution clearly below 5 nm. Technical solutions to reduce the space charge effect in an aberration-corrected spectro-microscope are discussed.
- Published
- 2013
49. Phase transformations in thin iron oxide films: Spectromicroscopic study of velocity and shape of the reaction fronts
- Author
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Alessandro Sala, Hans-Joachim Freund, Francesca Genuzio, Dietrich Menzel, and Thomas Schmidt
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Low-energy electron diffraction ,Oxide ,Front (oceanography) ,02 engineering and technology ,Surfaces and Interfaces ,Substrate (electronics) ,Activation energy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Molecular physics ,0104 chemical sciences ,Surfaces, Coatings and Films ,Low-energy electron microscopy ,Crystallography ,chemistry.chemical_compound ,Photoemission electron microscopy ,chemistry ,Phase (matter) ,Materials Chemistry ,0210 nano-technology - Abstract
Combining low energy electron microscopy (LEEM) with low energy electron diffraction (LEED) and x-ray photoemission electron microscopy (XPEEM), we studied the phase transformations between Fe3O4, γ-Fe2O3, and α-Fe2O3, grown as 10 nm thin oxide films on Pt(111) and Ag(111) single crystals. These transformations occur as moving reaction fronts in most cases, the shapes and velocities of which show strong dependences on temperature and oxygen pressure, but also on defects like step bunches of the supporting substrate and domain boundaries in the initial oxide film. While the non-uniform moving fronts make quantitative analysis difficult, we have extracted approximate values for the average front velocities. We discuss these as well as the qualitative information on the non-uniform fronts in terms of the known geometric situations and the likely motional steps.
- Published
- 2016
50. Small and Medium Enterprises Collaborations with Knowledge Intensive Services: An Explorative Analysis of the Impact of Innovation Vouchers
- Author
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Alessandro, Sala, Paolo, Landoni, and Verganti, Roberto
- Published
- 2016
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