| 1. |
- Agosti, Edoardo, et al.
(författare)
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Quantitative Anatomic Comparison of Endoscopic Transnasal and Microsurgical Transcranial Approaches to the Anterior Cranial Fossa
- 2022
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Ingår i: Operative Neurosurgery. - : Congress of Neurological Surgeons. - 2332-4252 .- 2332-4260. ; 23:4, s. e256-e266
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Several microsurgical transcranial approaches (MTAs) and endoscopic transnasal approaches (EEAs) to the anterior cranial fossa (ACF) have been described.OBJECTIVE: To provide a preclinical, quantitative, anatomic, comparative analysis of surgical approaches to the ACF.METHODS: Five alcohol-fixed specimens underwent high-resolution computed tomography. The following approaches were performed on each specimen: EEAs (transcribriform, transtuberculum, and transplanum), anterior MTAs (transfrontal sinus interhemispheric, frontobasal interhemispheric, and subfrontal with unilateral and bilateral frontal craniotomy), and anterolateral MTAs (supraorbital, minipterional, pterional, and frontotemporal orbitozygomatic approach). An optic neuronavigation system and dedicated software (ApproachViewer, part of GTx-Eyes II—UHN) were used to quantify the working volume of each approach and extrapolate the exposure of different ACF regions. Mixed linear models with random intercepts were used for statistical analyses.RESULTS: EEAs offer a large and direct route to the midline region of ACF, whose most anterior structures (ie, crista galli, cribriform plate, and ethmoidal roof) are also well exposed by anterior MTAs, whereas deeper ones (ie, planum sphenoidale and tuberculum sellae) are also well exposed by anterolateral MTAs. The orbital roof region is exposed by both anterolateral and lateral MTAs. The posterolateral region (ie, sphenoid wing and optic canal) is well exposed by anterolateral MTAs.CONCLUSION: Anterior and anterolateral MTAs play a pivotal role in the exposure of most anterior and posterolateral ACF regions, respectively, whereas midline regions are well exposed by EEAs. Furthermore, certain anterolateral approaches may be most useful when involvement of the optic canal and nerves involvement are suspected.
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| 2. |
- Baraldi, Alessandro, et al.
(författare)
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The (1x1)-> hexagonal structural transition on Pt(100) studied by high-energy resolution core level photoemission
- 2007
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 127:16
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Tidskriftsartikel (refereegranskat)abstract
- The (1 x 1)-> quasihexagonal (HEX) phase transition on a clean Pt(100) surface was investigated by monitoring the time evolution of the Pt4f(7/2) core level photoemission spectra. The spectral component originating from the atoms forming the (1 x .1) metastable unreconstructed surface was found at -570 +/- 20 meV with respect to the bulk peak. Ab initio calculations based on density functional theory confirmed the experimental assignment. At temperatures above 370 K, the (1 x 1) phase irreversibly reverts to the more stable HEX phase, characterized by a surface core level shifted component at -185 +/- 40 meV. By analyzing the intensity evolution of the core level components, measured at different temperatures in the range of 393-475 K, we determined the activation energy of the phase transformation, E=0.76 +/- 0.04 eV. This value is considerably lower than the one previously determined by means of low energy electron diffraction. Possible reasons for this discrepancy are discussed.
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| 3. |
- Bravi, Luca, et al.
(författare)
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Endothelial Cells Lining Sporadic Cerebral Cavernous Malformation Cavernomas Undergo Endothelial-to-Mesenchymal Transition
- 2016
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Ingår i: Stroke. - 0039-2499 .- 1524-4628. ; 47:3, s. 886-890
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Cerebral cavernous malformation (CCM) is characterized by multiple lumen vascular malformations in the central nervous system that can cause neurological symptoms and brain hemorrhages. About 20% of CCM patients have an inherited form of the disease with ubiquitous loss-of-function mutation in any one of 3 genes CCM1, CCM2, and CCM3. The rest of patients develop sporadic vascular lesions histologically similar to those of the inherited form and likely mediated by a biallelic acquired mutation of CCM genes in the brain vasculature. However, the molecular phenotypic features of endothelial cells in CCM lesions in sporadic patients are still poorly described. This information is crucial for a targeted therapy.METHODS: We used immunofluorescence microscopy and immunohistochemistry to analyze the expression of endothelial-to-mesenchymal transition markers in the cavernoma of sporadic CCM patients in parallel with human familial cavernoma as a reference control.RESULTS: We report here that endothelial cells, a cell type critically involved in CCM development, undergo endothelial-to-mesenchymal transition in the lesions of sporadic patients. This switch in endothelial phenotype has been described only in genetic CCM patients and in murine models of the disease. In addition, TGF-β/p-Smad- and β-catenin-dependent signaling pathways seem activated in sporadic cavernomas as in familial ones.CONCLUSIONS: Our findings support the use of common therapeutic strategies for both sporadic and genetic CCM malformations.
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| 4. |
- Brondin, Carlo Alberto, et al.
(författare)
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Tailoring Magnetic Anisotropy in Ultrathin Cobalt by Surface Carbon Chemistry
- 2024
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Ingår i: Advanced Electronic Materials. - 2199-160X. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- The ability to manipulate magnetic anisotropy is essential for magnetic sensing and storage tools. Surface carbon species offer cost-effective alternatives to metal-oxide and noble metal capping layers, inducing perpendicular magnetic anisotropy in ultrathin ferromagnetic films. Here, the different mechanisms by which the magnetism in a few-layer-thick Co thin film is modified upon adsorption of carbon monoxide (CO), dispersed carbon, and graphene are elucidated. Using X-ray microscopy with chemical and magnetic sensitivity, the in-plane to out-of-plane spin reorientation transition in cobalt is monitored during the accumulation of surface carbon up to the formation of graphene. Complementary magneto-optical measurements show weak perpendicular magnetic anisotropy (PMA) at room temperature for dispersed carbon on Co, while graphene-covered cobalt exhibits a significant out-of-plane coercive field. Density-functional theory (DFT) calculations show that going from CO/Co to C/Co and to graphene/Co, the magnetocrystalline and magnetostatic anisotropies combined promote out-of-plane magnetization. Anisotropy energies weakly depend on carbidic species coverage. Instead, the evolution of the carbon chemical state from carbidic to graphitic is accompanied by an exponential increase in the characteristic domain size, controlled by the magnetic anisotropy energy. Beyond providing a basic understanding of the carbon-ferromagnet interfaces, this study presents a sustainable approach to tailor magnetic anisotropy in ultrathin ferromagnetic films. Magnetic properties of Co ultrathin films are shown to undergo dramatic changes upon surface carbon accumulation. Chemical transformation from molecular carbon monoxide to surface carbide and to a graphene layer progressively enhances the perpendicular magnetic anisotropy of Co. Calculations reveal that magnetocrystalline and magnetostatic contributions play distinctly different roles for the different carbon species.image
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| 5. |
- Genuzio, Francesca, et al.
(författare)
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A UHV MOKE magnetometer complementing XMCD-PEEM at the Elettra Synchrotron
- 2021
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 28, s. 995-1005
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Tidskriftsartikel (refereegranskat)abstract
- We report on a custom-built UHV-compatible Magneto-Optical Kerr Effect (MOKE) magnetometer for applications in surface and materials sciences, operating in tandem with the PhotoEmission Electron Microscope (PEEM) endstation at the Nanospectroscopy beamline of the Elettra synchrotron. The magnetometer features a liquid-nitrogen-cooled electromagnet that is fully compatible with UHV operation and produces magnetic fields up to about 140 mT at the sample. Longitudinal and polar MOKE measurement geometries are realized. The magneto-optical detection is based on polarization analysis using a photoelastic modulator. The sample manipulation system is fully compatible with that of the PEEM, making it possible to exchange samples with the beamline endstation, where complementary X-ray imaging and spectroscopy techniques are available. The magnetometer performance is illustrated by experiments on cobalt ultra-thin films, demonstrating close to monolayer sensitivity. The advantages of combining in situ growth, X-ray Magnetic Circular Dichroism imaging (XMCD-PEEM) and MOKE magnetometry into a versatile multitechnique facility are highlighted.
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| 6. |
- Jugovac, Matteo, et al.
(författare)
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Coupling Borophene to Graphene in Air-Stable Heterostructures
- 2023
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Ingår i: Advanced Electronic Materials. - 2199-160X. ; 9:8
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Tidskriftsartikel (refereegranskat)abstract
- Artificial 2D van der Waals heterostructures with controllable vertical stacking and rotational orientation exhibit multifaceted electronic properties that are appealing for applications in fields ranging from optoelectronics to energy storage. Along with transition metal dichalcogenides and graphene, borophene has recently emerged as a promising building block for 2D devices due to its conductive nature as well as its exceptional mechanical and electronic properties. Here, it is demonstrated that the combination of the dissolution-segregation process and chemical vapor deposition allows for the synthesis of graphene/borophene heterostructures of the highest crystalline and chemical quality, in which graphene sits on top of the borophene layer with metallic character. The formation of laterally distinct micron-sized areas allows a comparative study of borophene, graphene, and the graphene–borophene heterostack in terms of their electronic properties and stability in a reactive environment. Whereas pristine borophene is particularly prone to oxidation, the graphene–borophene heterostack is chemically inert and enables the conservation of borophene's character even after exposure to air. This study opens up new perspectives for the scalable synthesis of graphene–borophene heterostacks with enhanced ability to preserve the metallic character and electronic properties of borophene.
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| 7. |
- Leurent, Martin, et al.
(författare)
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Driving forces and obstacles to nuclear cogeneration in Europe: Lessons learnt from Finland
- 2017
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Ingår i: Energy Policy. - : ELSEVIER SCI LTD. - 0301-4215 .- 1873-6777. ; 107, s. 138-150
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear power plants generate electricity and a large amount of waste heat which is valuable for cogeneration. District heating (DH) is a suitable technology to decarbonize the European heat sector. By contrast with most of nuclear non-electric applications, nuclear district heating (NDH) has already been implemented in Europe, thus providing us with some valuable empirical insights. This paper investigates the forces and obstacles to nuclear cogeneration by looking at the Loviisa 3 NDH project in Finland. The key forces are energy efficiency, decarbonization of the heat sector, operational competitiveness of future nuclear technologies, and synergies with renewable energies. The key obstacles are split incentives, electricity prices volatility, inexpediency of business models and regulatory frameworks, electioneering of local authorities and pessimist expectations with regards to project financing. Policy makers should recognize nuclear plants alongside other utilities generating large amounts of wasted heat. International cooperation programs involving both nuclear and heat stakeholders should be encouraged. EU28 Member States wanting to promote nuclear cogeneration may consider providing support for the electricity generated by high-efficiency plants.
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| 8. |
- Pedersoli, Emanuele, et al.
(författare)
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Multipurpose modular experimental station for the DiProI beamline of Fermi@Elettra free electron laser
- 2011
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 82:4, s. 043711-
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Tidskriftsartikel (refereegranskat)abstract
- We present a compact modular apparatus with a flexible design that will be operated at the DiProI beamline of the Fermi@Elettra free electron laser (FEL) for performing static and time-resolved coherent diffraction imaging experiments, taking advantage of the full coherence and variable polarization of the short seeded FEL pulses. The apparatus has been assembled and the potential of the experimental setup is demonstrated by commissioning tests with coherent synchrotron radiation. This multipurpose experimental station will be open to general users after installation at the Fermi@Elettra free electron laser in 2011.
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| 9. |
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