3 research outputs found
Salivary Vasopressin as A Potential Non–Invasive Biomarker of Anxiety in Dogs Diagnosed with Separation–Related Problems
No full textPhysiological biomarkers of canine anxiety have not been extensively investigated to date. To identify new biomarkers in dogs, we compared behaviorally normal dogs (Control group, N = 13) to dogs diagnosed with separation problems (Case group, N = 13) as they were introduced into a novel environment in the presence of two strangers and subjected to a short episode of separation and reunion with the owner. During the separation phase, dogs in the Case group explored significantly less than controls and were significantly more persistent in expressing passive stress-coping strategies aimed at seeking proximity to their owners. When the owners returned, dogs with separation distress spent significantly more time jumping up on the strangers than control dogs did. Salivary oxytocin and vasopressin concentrations did not differ between samples taken before and after the separation. However, vasopressin concentrations immediately after separation were significantly higher in the Case than in the Control group and remained higher, although not significantly so, 10 minutes later. These results indicated that dogs with separation distress became more anxious than typical dogs when separated from their owner in an unfamiliar environment and provided preliminary support for the use of salivary vasopressin as a possible biomarker for anxiety-related responses in dogs
Development of alternative plasmonic Ta:TiO2/TiN multilayers as a platform for novel hyperbolic metamaterials
No full textLAUREA MAGISTRALELa plasmonica è una branca della fotonica che studia l’interazione tra un campo elettromagnetico e i metalli. Negli ultimi anni sono stati studiati nuovi materiali plasmonici, come i semiconduttori e i nitruri di metalli di transizione, per superare le limitazioni legate all'uso dei materiali tradizionali. Questi nuovi materiali plasmonici sono interessanti per la possibilità di sviluppare una nuova classe di materiali chiamati metamateriali iperbolici (HMMs), che sono metamateriali caratterizzati da strutture altamente anisotrope e da una geometria relativamente semplice. Esistono due strutture principali sviluppate per ottenere un comportamento iperbolico: l'alternanza di strati di metallo e dielettrico o nanofili posizionati in una matrice dielettrica. Nel corso di questo progetto, sono stati modellati, depositati e caratterizzati multistrati iperbolici basati su TiN e Ta:TiO2, con l'obiettivo di comprendere gli effetti della temperatura di deposizione, della geometria e dei materiali scelti sulle proprietà delle strutture. Per modellare gli HMMs, sono stati depositati e caratterizzati singoli strati di TiN e Ta:TiO2. Sono state poi depositate e caratterizzate due serie di multistrati, concentrando l'attenzione prima sull'effetto dell'ordine degli strati e della temperatura di deposizione sulle proprietà ottiche dei multistrati, e poi sull'effetto dei materiali selezionati e dello spessore degli strati sulle proprietà plasmoniche e ottiche dei campioni. Sono stati esplorati gli effetti della temperatura del substrato sulla deposizione di singoli strati di TiN, Ta:TiO2 e multistrati. Il comportamento iperbolico delle diverse strutture è stato previsto mediante simulazioni, basate sulla teoria del mezzo efficace. Una dipendenza dalla geometria della risposta ottica dei multistrati è stata osservata attraverso le simulazioni e confermata dai dati sperimentali. Alla luce dei risultati ottenuti, le possibili prospettive future potrebbero risiedere nella selezione di diversi materiali per ampliare l’intervallo di iperbolicità e in un'analisi più approfondita degli effetti della geometria sulle proprietà plasmoniche della struttura multistrato.Plasmonics is a branch of photonics that deals with the interaction between an electromagnetic field and metals. In the recent years novel plasmonic material, such as semiconductors and transition metal nitrides, have been investigated to overcome the limitation related to the use of the traditional ones. These novel plasmonic materials are interesting for the possibility of developing a new class of materials called hyperbolic metamaterials (HMMs), which are metamaterials characterized by highly anisotropic structures and relatively simple geometry . There are two main structures developed to obtain a hyperbolic behaviour: alternation of sub-wavelength layers of metal and dielectric or arrays of nanorod placed in a dielectric matrix. During this project, hyperbolic multilayers based on TiN and Ta:TiO2 have been modelled, deposited and characterized with the objective of understanding the effects of the deposition temperature, geometry and materials selected on the properties of the structures. To model HMMs, single layers of TiN and Ta:TiO2 have deposited and characterized. Then two sets of multilayers have been deposited and characterized focusing the attention firstly on the effect of the order of the layers and of the deposition temperature on the optical properties of the multilayers, and secondly on the effect of the materials selected and the thickness of the layers on the plasmonic and optical properties of the samples. The effects of the substrate temperature on the deposition of single layers of TiN, Ta:TiO2 and multilayers has been explored. The hyperbolic behaviour of the different structures has been predicted by means of simulations, based on the effective medium theory. A geometry dependence of the optical response of multilayers has been observed through simulations and confirmed by experimental data. In view of the results obtained, possible future perspectives could lie in the selection of different materials to enlarge the range of wavelengths in which a hyperbolic behaviour is shown, and in a deeper analysis of the effects of the geometry on the plasmonic properties of the multilayered structure
Salivary Vasopressin as A Potential Non–Invasive Biomarker of Anxiety in Dogs Diagnosed with Separation–Related Problems
No full textVideo S1: A dog is showing signs of stress while the owner is out of the arena and the veterinary behaviorist is engaging the dog in friendly interaction, including gently petting her and speaking to her in a calm tone.
Video S2: A dog is exhibiting signs of severe distress and anxiety; consequently, the owner is asked to come back, and the test is stopped.
Video S3. A dog in the Case group persists in jumping up on the veterinary behaviorist during the post- separation reunion phase.</p
