Search results for "Physis"
showing 10 items of 102 documents
Diffusive motions in HD films physisorbed on graphite
2003
Abstract High-resolution quasielastic neutron scattering was used to study diffusive motions in two-dimensional liquid and solid phases of deuterium hydride submonolayers adsorbed on graphite (Papyex). For the first time it could be unambiguously clarified that the novel reentrant fluid phase at the commensurate–incommensurate transition has the character of a viscous fluid.
Superheavy element flerovium (element 114) is a volatile metal.
2014
The electron shell structure of superheavy elements, i.e., elements with atomic number Z ≥ 104, is influenced by strong relativistic effects caused by the high Z. Early atomic calculations on element 112 (copernicium, Cn) and element 114 (flerovium, Fl) having closed and quasi-closed electron shell configurations of 6d(10)7s(2) and 6d(10)7s(2)7p1/2(2), respectively, predicted them to be noble-gas-like due to very strong relativistic effects on the 7s and 7p1/2 valence orbitals. Recent fully relativistic calculations studying Cn and Fl in different environments suggest them to be less reactive compared to their lighter homologues in the groups, but still exhibiting a metallic character. Expe…
Selective chemisorption of carbon monoxide by organic-inorganic hybrid materials incorporating cobalt(III) corroles as sensing components.
2007
Twenty-one hybrid materials incorporating cobalt(III) corrole complexes were synthesized by a sol–gel process or by grafting the metallocorrole onto a mesostructured silica of the SBA-15 type. All the materials show an almost infinite selectivity for carbon monoxide with respect to dinitrogen and dioxygen in the low-pressure domain where the chemisorption phenomenon is predominant. This peculiar property is of prime importance for an application as a CO sensor. The selectivity slightly decreases at high pressures where nonselective physisorption phenomena mainly occur. The percentage of active sites for CO chemisorption ranges from 22 to 64 %. This low percentage may be attributable to inte…
La pubalgia nello sportivo: quadri RM di “Osteite Pubica"
2005
La pubalgia è una sindrome dolorosa, a volte a carattere invalidante, che colpisce sia gli sportivi agonisti che quelli amatoriali, rappresenta il 2-5% delle patologie correlate all’attività sportiva agonistica e non sempre le sue cause sono facilmente diagnosticabili. L’osteite pubica rappresenta una delle principali cause di dolore inguinale e colpisce gli sportivi nel 0,5-0,7% dei casi. Dal settembre 2003 all’agosto 2004, 40 atleti, 37 uomini e 3 donne (età compresa tra 18 e 37 anni; età media: 24 anni), con diagnosi clinica di pubalgia sono stati sottoposti a RM del bacino. In tutti i casi la sintomatologia era caratterizzata da dolore mono (33%) o bilaterale (67%) con irradiazione alla…
Logos e Physis. Il libro A della Physica di Aristotele
2023
Perché rileggere la Physica di Aristotele oggi? E perché rileggere, in particolare, il suo libro iniziale? Attraverso una full immersion nel testo e nella lettura critica degli ultimi settant’anni, l’autore cerca di dar risposta a questa domanda. Il punto di partenza è Omero e la cultura greca delle origini. Una tappa intermedia obbligata è la riflessione sulla testualità aristotelica. I testi di Aristotele pervenutici sono opere acroamatiche: ossia appunti per una performance didattica orale. Se questo è vero, Aristotele non è l’inventore del moderno trattato specialistico. Ma neppure inaugura in Grecia un modello ‘dipartimentale’ dei saperi. La Physica di Aristotele non è una scienza spec…
Severe X-linked chondrodysplasia punctata in nine new female fetuses
2015
ObjectivesConradi-Hunermann-Happle [X-linked dominant chondrodysplasia punctata 2 (CDPX2)] syndrome is a rare X-linked dominant skeletal dysplasia usually lethal in men while affected women show wide clinical heterogeneity. Different EBP mutations have been reported. Severe female cases have rarely been reported, with only six antenatal presentations. MethodsTo better characterize the phenotype in female fetuses, we included nine antenatally diagnosed cases of women with EBP mutations. All cases were de novo except for two fetuses with an affected mother and one case of germinal mosaicism. ResultsThe mean age at diagnosis was 22weeks of gestation. The ultrasound features mainly included bon…
Surface Characteristics Control the Attachment and Functionality of (Chimeric) Avidin
2018
The physical adsorption (physisorption) of proteins to surfaces is an important but incompletely understood factor in many biological processes and is of increasing significance in bionanotechnology as well. Avidin is an important protein because of strong avidin–biotin binding, which has been exploited in numerous applications. We have undertaken thorough experimentation on the physisorption of avidin, to chemically different flat surfaces of Si and graphite and also to the curved version of the latter, on multiwalled carbon nanotubes (MWNTs) of different diameters. The difference in the behavior of avidin on Si versus graphite is drastic; on Si, avidin deposits as single globular tetramer…
Architecture in cortical bone and ultrasound transmission velocity
1993
The square of ultrasound transmission velocity in a material is correlated to the modulus of elasticity, which is an indicator of its mechanical properties. This might make the measurement of ultrasound transmission velocity useful in the noninvasive diagnosis of bone diseases. Bone, however, is not an isotropic material but is architecturally structured. The aim of our study was to investigate and especially to quantify the influence of architecture in cortical bone on ultrasound transmission velocity. Twenty-two rectangular, flat specimens of cortical bone were prepared from diaphysis of fresh pig radius. Ultrasound transmission velocity was measured parallel and perpendicular to directio…
Thermogravimetric and Sorption Measurement Techniques/Instruments
2002
The survey covers commercially offered instruments for the determination of the surface structure of porous solids based on isothermal measurement of physisorption of inert gases and of thermogravimetric instruments. Basic assumptions, features and experimental uncertainties are compared.
Characterization and utilization of MFI zeolites and MCM-41 materials for gaseous pollutant adsorption
1999
Physisorption of n-hexane, trichloroethylene, tetrachloroethylene, carbon and nitrogen oxides on a microporous ZSM-5 (Si/Al=339) zeolite and an amorphous mesoporous MCM-41 (Si/Al=∞) sample was examined by isothermal thermogravimetry, manometry and calorimetry to evaluate the feasibility of using these porous materials for gaseous pollutant adsorption at room temperature. The adsorbents showed very interesting adsorption properties for hydrocarbons. ZSM-5 exhibited the strongest adsorption affinity and MCM-41 showed the largest adsorption capacity. Another main feature in this work was to observe a stepped-isotherm for the adsorption of C2Cl4 on ZSM-5. Such a substep located at very low rela…