Search results for "Ribb"
showing 10 items of 153 documents
Circadian and Infradian Activity Rhythms in the Mammalian Pineal Body
1982
The neuroendocrine nature of the pineal organ is well established. Linked to the optic system via postganglionic sympathetic fibres coming from the superior cervical ganglia, the parenchymal cells of the pineal synthesize serotonin from tryptophan and convert it to melatonin, the most widely studied pineal substance, and other indoleamines. Melatonin synthesis is stimulated by noradrenaline released from intrapineal sympathetic nerve fibres, involving β-adrenergic mechanisms and the adenyl cyclase-cAMP-system. The rate-limiting enzyme of melatonin formation is serotonin-N-acetyltransferase (NAT) that converts serotonin to N-acetylserotonin. Hydroxyindole-O-methyltransferase (HIOMT) catalyze…
Synthesis of Nonplanar Graphene Nanoribbon with Fjord Edges
2021
As a new family of semiconductors, graphene nanoribbons (GNRs), nanometer-wide strips of graphene, have appeared as promising candidates for next-generation nanoelectronics. Out-of-plane deformation of π-frames in GNRs brings further opportunities for optical and electronic property tuning. Here we demonstrate a novel fjord-edged GNR (FGNR) with a nonplanar geometry obtained by regioselective cyclodehydrogenation. Triphenanthro-fused teropyrene 1 and pentaphenanthro-fused quateropyrene 2 were synthesized as model compounds, and single-crystal X-ray analysis revealed their helically twisted conformations arising from the [5]helicene substructures. The structures and photophysical properties …
Narrativa dei Caraibi nel nuovo millennio
2020
L’etichetta “Letterature franco-caraibica” utilizzata, per convenzione, dalla critica per indicare unitariamente la produzione letteraria in lingua francese della regione centrale del Continente americano è assai impropria. La regione dei Caraibi abbraccia, infatti, sia alcune delle isole dell’arcipelago delle Piccole Antille (Martinica, Guadalupa), sia l’isola di Haïti, che fa parte delle Grandi Antille, che la Guiana incastonata sulla costa orientale dell’America meridionale. Pur nella diversità dei movimenti ideologici e degli avvenimenti storici che si sono succeduti nella regione, le opere letterarie degli scrittori caraibici francofoni, nel loro insieme, hanno oscillato, e continuano …
Caraibi: un "archipel inachevé"
2018
L’etichetta “Letterature franco-caraibica” utilizzata, per convenzione, dalla critica per indicare unitariamente la produzione letteraria in lingua francese della regione centrale del Continente americano è assai impropria. La regione dei Caraibi abbraccia, infatti, sia alcune delle isole dell’arcipelago delle Piccole Antille (Martinica, Guadalupa), sia l’isola di Haïti, che fa parte delle Grandi Antille, che la Guiana incastonata sulla costa orientale dell’America meridionale. Pur nella diversità dei movimenti ideologici e degli avvenimenti storici che si sono succeduti nella regione, le opere letterarie degli scrittori caraibici francofoni, nel loro insieme, hanno oscillato, e continuano …
Unusual case of continuous urinary dribbling in a young female due to unknown complex urogenital malformation: magnetic resonance features
2020
Congenital anomalies of kidney and urinary tract (CAKUT) occur in up to 3.2% of infants, and in almost one third of cases they are associated to genital aberrations. DMSA renal scintigraphy is considered the gold standard in CAKUT patients, to assess renal function, depict and locate ectopic kidney and to guide eventual surgical management. Recent cases have shown the noticeable limit of scintigraphy in detecting poorly functional renal moieties and associated genital anomalies; thus leading to a substantial delay in therapy, and, in females, to severe uro-gynecological complications. We herein describe a case of a young girl with unusual urinary dribbling, where DSMA scintigraphy was not d…
Impact of mandatory social isolation measures due to the COVID-19 pandemic on the subjective well-being of Latin American and Caribbean dentists
2022
Background With the spread of the COVID-19 virus, containment measures such as home confinement were implemented, generating stress, anxiety, depression and aggravation of pre-existing diseases in the population, including dentists, who have also been affected due to the risk involved in practicing their profession. Objective: To determine the impact of mandatory social isolation measures on the subjective well-being of Latin American and Caribbean dentists during the community quarantine due to the COVID-19 pandemic in 2020. Material and Methods A Cross-sectional study in a sample of 1195 dentists from 21 countries in Latin America and the Caribbean. The main outcome was Subjective Well-Be…
Controlled production of patchy particles from the combined effects of nanoprecipitation and vitrification
2017
Using molecular dynamics simulations, we study a simple and scalable method for fabricating patchy nanoparticles via the assembly of binary polymer blends under a rapid solvent exchange. Patchiness can be achieved by incorporating a glassy component, which kinetically traps the particle morphology along the path to the equilibrium configuration. Our simulations reveal that the number of surface patches increases for larger nanoparticles and for more asymmetric blend ratios, while the size distribution of the patches remains rather uniform. Other than multi-patch nanoparticles, Janus structures have been obtained for small nanoparticles. Further, ribbon structures with elongated surface doma…
On codimension two embeddings up to link-homotopy
2017
We consider knotted annuli in 4-space, called 2-string-links, which are knotted surfaces in codimension two that are naturally related, via closure operations, to both 2-links and 2-torus links. We classify 2-string-links up to link-homotopy by means of a 4-dimensional version of Milnor invariants. The key to our proof is that any 2-string link is link-homotopic to a ribbon one; this allows to use the homotopy classification obtained in the ribbon case by P. Bellingeri and the authors. Along the way, we give a Roseman-type result for immersed surfaces in 4-space. We also discuss the case of ribbon k-string links, for $k\geq 3$.
Les phiales étrusques de type Vetulonia/Colmar de la tomba del carrettino à Ca’ Morta (Côme, Italie) : essai de contre-typologie.
2021
AbstractA new study of the patere baccellate from the Tomba del carrettino at Ca’ Morta offers the opportunity to re-examine the typology of the ribbed bowls of Vetulonia/Colmar type and to re-evaluate their funerary contexts. These vessels appear in central and southern Etruria at the end of the eighth and the beginning of the seventh century BC, the site of Vetulonia being considered as their main production site.Ferdinando Sciacca’s (2005) classification of the ribbed bowls of Vetulonia/Colmar type is supported by solid evidence ; it has advanced the subject significantly, but Sciacca’s model nevertheless raises some questions in terms of the hierarchy of the criteria that were chosen.Du…
Theoretical Simulations on Electric Properties of CNT-Me and GNR-Me Interconnects Using Effective Media Approach
2011
Abstract To overcome disadvantages of nowadays microtechnology, a further miniaturization of electronic devices, high integration level as well as increase of both operation frequencies and power density is required, including the use of adequate materials and innovative chip interconnects. Due to their unique physical properties, especially due to a ballistic (without losses) mechanism of conductivity, carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) attract a permanently growing technological interest, for example, as promising candidates for nanointerconnects in a high-speed electronics.