274 research outputs found

    The Columbus logistics support at the APMC: Requirements and implementation aspects

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    This paper focuses on the logistics support to be provided by the APM Center (APMC). Among the Columbus ground infrastructures, this center is tasked to provide logistics, sustaining engineering and P/L integration support to the ongoing missions of the APM, i.e. the Columbus Laboratory attached to the Freedom Space Station. The following is illustrated: an analysis of the requirements that are levied on the logistics support of the APM; how such requirements are reflected in the corresponding support to be available on-ground and at APMC; the functional components of the APMC logistics support and how such components interact each other; how the logistics support function interfaces with the other functions of the ground support; and how the logistics support is being designed in terms of resources (such as hardware, data bases, etc.). Emphasis is given to the data handling aspects and to the related data bases that will constitute for the logistics activities the fundamental source of information during the APM planned lifetime. Functional and physical architectures, together with trades for possible implementation, are addressed. Commonalities with other centers are taken into account and recommendations are made for possible reuse of tools already developed in the C/D phase. Finally, programmatic considerations are discussed for the actual implementation of the center

    Urgent Carotid Surgery: Is It Still out of Debate?

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    Patients with symptomatic tight carotid stenosis have an increased short-time risk of stroke and an increased long-term risk of ischaemic vascular events compared with the general population. The aim of this study is to assess the safety, efficacy, and limitations of urgent CEA or CAS, in patients with carotid stenosis greater than 70% and clinically characterized by recurrent TIA or brain damage following a stroke (<2.5 cm). This study involved 28 patients divided into two groups. Group A consisted of sixteen patients who had undergone CEA, and group B consisted of twelve patients who had undergone CAS. Primary endpoints were mortality, neurological morbidity (by NIHSS) and postoperative hemorrhagic cerebral conversion, at 30 days. Ten patients (62.5%) of group A experienced an improvement in their initial neurological deficit while in 4 cases (26%) the deficit remained stable. Two cases of neurologic mortality are presented. At 1 month, 9 patients (75%) of group B experienced an improvement in their initial neurological deficit while 3 patients (25%) had a neurological impairment. Urgent or deferred surgical or endovascular treatment have a satisfactory outcome considering the profile in very high-risk patient population. Otherwise in selected patients CEA seems to be preferred to CAS

    Acute occlusion of descending thoracic aorta

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    Acute aortic occlusion is a rare but potentially devastating clinical event, which requires a prompt diagnosis and emergency treatment. Only 5 cases of native thoracic aorta acute occlusion have so far been reported with different pathologic causes. The clinical features depend on the level of occlusion. Sometimes the diagnosis could be misinterpreted as a stroke or other diseases of the central nervous system. This could lead to a delay in the diagnosis and revascularization procedure, followed by a morbidity or mortality increase. Open surgery has been considered the first-line approach. This study is of a female patient suffering from acute descending thoracic aorta occlusion undergoing, for the first time to our knowledge, endovascular surgical treatment

    Noble metal nanoparticles networks stabilized by rod-like organometallic bifunctional thiols

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    Rod-like organometallic dithiol containing square-planar Pt(II) centers, i. e., trans,trans-[(H3COCS)Pt(PBu3)(2)(C equivalent to C-C6H4-C6H4-C equivalent to C)(PBu3)(2)Pt(SCOCH3)] was used as bifunctional stabilizing agent for the synthesis of Pd-, Au-, and AgNPs (MNPs). All the MNPs showed diameters of about 4 nm, which can be controlled by carefully modulating the synthesis parameters. Covalent MNPs stabilization occurred through a single S bridge between Pt(II) and the noble metal nanocluster surfaces, leading to a network of regularly spaced NPs with the formation of dyads, as supported by SR-XPS data and by TEM imaging analysis. The chemical nature of NPs systems was also confirmed by EDS and NMR. Comparison between SR-XPS data of MNPs and self-assembled monolayers and multilayers of pristine rod-like dithiols deposited onto polycrystalline gold surfaces revealed an electronic interaction between Pt(II) centers and biphenyl moieties of adjacent ligands, stabilizing the organic structure of the network. The possibility to obtain networks of regularly spaced MNPs opens outstanding perspectives in optoelectronics

    Electrify Italy

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    This study explores a possible pathway to implement a new energy paradigm in Italy based on electrification. The objectives are: • To build a forward-looking vision of possible scenarios at 2022, 2030 and 2050 by integrating a multi-focus perspective on the penetration of renewables and the electrification potential of the residential, industrial and transport sectors. • To estimate the potential benefits of further electrification through the calculation of Key Performance Indicators in four different areas: energy, economy, environment and society. The study shows how the electricity triangle, a paradigm based on clean generation by renewable sources, electrification of final uses, and electricity exchange through efficient smart grids, closes the loop of clean energy and efficient consumption. This leads to improvements in energy, environment, economy and social performances, and boosts the share of renewables in final consumption

    Electronic structure and molecular orientation of a Zn-tetra-phenyl porphyrin multilayer on Si(111)

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    The electronic properties and the molecular orientation of Zn-tetraphenyl-porphyrin films deposited on Si(111) have been investigated using synchrotron radiation. For the first time we have revealed and assigned the fine structures in the electronic spectra related to the HOMOs and LUMOs states. This is particularly important in order to understand the orbital interactions, the bond formation and the evolution of the electronic properties with oxidation or reduction of the porphyrins in supramolecular donor-acceptor complexes used in photovoltaic devices.Comment: text 11 pages, 4 figures submitted for publicatio

    Mono- and bi-functional arenethiols as surfactants for gold nanoparticles: synthesis and characterization

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    Stable gold nanoparticles stabilized by different mono and bi-functional arenethiols, namely, benzylthiol and 1,4-benzenedimethanethiol, have been prepared by using a modified Brust's two-phase synthesis. The size, shape, and crystalline structure of the gold nanoparticles have been determined by high-resolution electron microscopy and full-pattern X-ray powder diffraction analyses. Nanocrystals diameters have been tuned in the range 2 ÷ 9 nm by a proper variation of Au/S molar ratio. The chemical composition of gold nanoparticles and their interaction with thiols have been investigated by X-ray photoelectron spectroscopy. In particular, the formation of networks has been observed with interconnected gold nanoparticles containing 1,4-benzenedimethanethiol as ligand
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