Design, fabrication and characterization of metamaterial inspired structures for sensing application

2011/2012In the last few years the interest in nanostructures for sensing application has grown increasingly, leading to the development of new designs based on the surface plasmon resonance of metallic structures. By carefully tuning the geometry of the nanostructures, it is possible to adjust the resonance frequencies, resulting in amplification and confinement of the electromagnetic field around specific areas of the structure. The oscillating plasmonic field obtained may be exploited for bio-chemical detection. In this work we present the design, the fabrication and the characterization of gold nano split ring resonators on transparent substrate, combining finite element simulation, lithographic techniques and transmittance ellipsometry. Bearing in mind the importance of the control of the geometric parameters, we approach the structure fabrication using top-down lithographic techniques. We explore and develop, in particular, an X-ray Lithography based process for producing high volumes of tall, nanometric split ring resonators. The choice of X-ray Lithography as the main technique is justified by the possibility to obtain higher aspect ratio and to achieve large areas array of split ring resonators in a single, fast exposure, compared to other techniques, such as nanoimprinting or Electron Beam Lithography. The structure we focused our research on is the split ring resonator, one of the most popular and studied geometries for metamaterials. As metamaterial building block, the split ring resonator exhibits characteristic plasmonic resonances and a tunable frequency magnetic resonance. Besides, the split ring resonator shows a strong polarization dependance and a strong mechanical stability. In this thesis we will analyze the optical properties of the split ring nanostructure when illuminated in normal incidence. The analysis of the response in transmission at two polarization is presented. The preliminary detection test performed using a monolayer of dodecanthiol evidence the detection potential of this geometry.XXV Ciclo198

Brain correlates of spike and wave discharges in GLUT1 deficiency syndrome

Purpose To provide imaging biomarkers of generalized spike-and-wave discharges (GSWD) in patients with GLUT1 deficiency syndrome (GLUT1DS). Methods Eighteen GLUT1DS patients with pathogenetic mutation in SLC2A1 gene were studied by means of Video-EEG simultaneously recorded with functional MRI (VideoEEG-fMRI). A control group of sex and age-matched patients affected by Genetic Generalized Epilepsy (GGE) with GSWD were investigated with the same protocol. Within and between groups comparison was performed as appropriated. For GLUT1DS, correlations analyses between the contrast of interest and the main clinical measurements were provided. Results EEG during fMRI revealed interictal GSWD in 10 GLUT1DS patients. Group-level analysis showed BOLD signal increases at the premotor cortex and putamen. With respect to GGE, GLUT1DS patients demonstrated increased neuronal activity in the putamen, precuneus, cingulate cortex, SMA and paracentral lobule. Whole-brain correlation analyses disclosed a linear relationship between the GSWD-related BOLD changes and the levels of glycorrhachia at diagnosis over the sensory-motor cortex and superior parietal lobuli. Conclusion The BOLD dynamics related to GSWD in GLUT1DS are substantially different from typical GGE showing the former an increased activity in the premotor-striatal network and a decrease in the thalamus. The revealed hemodynamic maps might represent imaging biomarkers of GLUT1DS, being potentially useful for a precocious diagnosis of this genetic disorder

Case report: KETOLAND the psychoeducation program for ketogenic diet

Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a rare neurological disorder characterized by a wide spectrum of symptoms: epilepsy, movement disorders and neurocognitive impairment. The gold standard treatment for GLUT1DS are ketogenic dietary therapies (KDTs), specifically classical ketogenic diet (CKD). Despite the benefits, CKD often represents a challenge for patients and their families since meal preparation is extremely demanding and deviates a lot from normal diet. To assure an optimal compliance to CKD a psychological support for parents and patients with GLUT1DS is highly recommended. Specifically, a psychoeducational intervention that ameliorates the knowledge about the illness and its therapy improves treatment' s adherence and efficacy. The aim of this case report is to investigate the effectiveness of a psychoeducational program, partially implemented through telepsychology, based on the theoretical model of Cognitive Behavioral Play Therapy (CBPT) to support KDT knowledge and adherence in a patient with GLUT1DS who presented a worsening of her clinical picture due to a sparse knowledge of KDTs principles which determined a low adherence. Thus, with this case report we propose a model of intervention with psychoeducation in a patient with a complex chronic disease