Browsing by Author "Bartolino, Roberto"

Now showing 1 - 20 of 72

<> study wind behavior from the micro to the mesoscale of different temporal and spatial horizons: turbulent regime, mean and climate
(2014-11-13) Tiriolo, Luca; Bartolino, Roberto; Sempreviva, Anna Maria; Carbone, Vincenzo
Absorpitive losses mitigation in gain-plasmon hybrid systems as optical metamaterials
(2013-11-29) Rashed, Alireza Rahimi; Bartolino, Roberto; Versace, Carlo C.; Strangi, Giuseppe
In the past decade, plasmonic nanoparticles (NPs) have gained a lot of interest due to their exceptional and fascinating properties which have been accomplishing vital role in emerging science and technology towards multifunctional applications. The extensive current research efforts in nanoplasmonics trigger towards various opto-electronic and medical applications such as invisibility, perfect lens, increasing the efficiency of solar cells, designing and extra-sensitive single-particle detection of biomolecular recognition and in particular optical metamaterials. The negative real part and the low value of the imaginary part of dielectric permittivity are crucial for applications of nanoparticles as subunits of optical metamaterials. However, the performance of plasmonic nanostructures is significantly limited by the intrinsic and strong energy dissipation in metals, especially in the visible range. In fact, regardless of the challenges to synthesize plasmonic nanostructures, the path to use them as building blocks of optical metamaterial is crossing through the finding a solution to mitigate their optical losses. In this research thesis, it is demonstrated experimentally that the incorporation of gain material such as organic dye molecules and quantum dots in close proximity of enhanced local fields of various properly designed plasmonic systems makes it possible to induce resonant energy transfer processes from gain units to plasmonic nanoparticles, to accompanish loss compensation in optical metamaterials. Steady-state experiments and time resolved spectroscopy along with modification of Rayleigh scattering and optical transmission of a probe beam as a function of impinging energy are crucial evidences of mitigation of absorptive losses in different gain doped plasmonic systems The strategy that has been followed here towards mitigation of absorptive losses in optical metamaterials acts at different spatial scales from nano to macro (see Figure 1). The systems at nano-scale (10-100 nm) are based on dispersion of NPs, in particular, gain assisted (nanoparticle-dye dispersion), gain-functionalized core-shell gold NPs (encapsulated dye molecules into the shell) and dye grafted gold core multimeric nanostructures. The study of such nano-composites allows to recognize experimentally how the parameters such as the geometry and size of the metal nanostructures, inter-particle distance, overlap between emission spectrum of gain material and plasmon band of metal NPs, concentration and quantum yield of donor molecules are playing an important role to create more efficient nonradiative RET processes from donor molecules to acceptors. Figure 1 The followed spatial stages on this research study ranged from (a) nano-scale and (b) mesco scale towards (c) macro scale. The obtained results in nano-scale generate further motivations to move forward to study meso-scale (100-900 nm) plasmonic systems which include both dispersion (nanoshell composites) and bulk (periodic layers of gain materials and lossy metal elements) systems. The nanoshells which are consisted of dye doped dielectric core coated gold shell dispersed in ethanol solution are designed with an optimized ratio of core diameter and metallic shell thickness. The time resolved fluorescence spectroscopy results along with pump-probe experiments on nanoshells are convincing evidences for optical loss mitigation. Finally in third stage, the optical properties of gain-plasmon composites dispersed in PDMS host matrix as an example for bulk samples at the macroscopic scale (1 μm and beyond) have been investigated. The achieved results on this stage can help to design and fabricate such plasmonic structures that lead from fundamental physics towards practical applications. In this regard, the first four chapters provide the background concerning the main elements of this research work. The first chapter contains an introduction to the metamaterials. Second chapter describes the optical properties of plasmonic nanostructures. In third chapter, gain materials and the optical processes beyond these materials have been investigated. The fourth chapter deals with the optical properties of hybrid systems consisted of active materials and nano-plasmonic elements. After providing a brief introduction regarding the applied setups and instruments in this research study in chapter five, the last three chapters represent the acquired experimental results in each mentioned spatial scale. In chapter six, the optical properties of nano-scaled gain-plasmon systems in solution including gain-assisted, gainfunctionalized and dye grafted multimeric samples are investigated. Chapter seven explores the optical characteristics of dispersion of nanoshell sample as an example of the study in mesoscale. Finally, the thesis is completed with the study of the optical features of macro-scaled bulk samples based on core–shell type quantum dots and gold NPs dispersed in PDMS, and a short conclusion of this research study. This study emphasizes effective progress in materials science and paves the way towards further promising scientific research aimed to enable the wide range of electromagnetic properties of plasmonic metamaterials
Across Scales Approach Based on Exciton-Plasmon Coupling for Low Loss Optical Metamaterials
(2015-12-15) Dhama, Rakesh; Bartolino, Roberto; Versace, Carlo; De Luca, Antonio
Active plasmonic nanostructures for biomedical applications
(Università della Calabria, 2020-03-27) Chatterjee, Sharmistha; Bartolino, Roberto; Strangi, Giuseppe
Real-time and label-free detection of protein molecules at ultralow concentration in their natural state is considered the “Holy-Grail” in biomedical research. Protein molecules pop up in the bodily fluids such as saliva, blood serum, at early stage of any infection or disease and circulate throughout the body. Therefore, the emergence of that particular infection or disease can be envisioned through the detection of the signature protein markers. The early detection of the disease would help to start the treatment early, and thus ensure therapeutic success which will eventually increase the survival rates and quality of life. The early detection of protein molecules is necessary for the diagnostics as well as for environmental monitoring, emergency response and homeland security. But the desired detection of protein molecules in the early stage is extremely challenging because of the ultralow concentration of the protein markers in the bodily fluid at the early stage and their acutely small size (< 3 nm). One way to overcome this hurdle is to use the extraordinary electromagnetic responses of noble metal nanoparticles (MNPs). Here stable gold nanostars (AuNS) have been synthesized to use their property for sensing. A surfactant-free, simple, one step wet-chemistry method was used to synthesize these spiky nanoparticles, which were stable in aqueous media for more than five months. Based on their characterization and the numerical analysis, it has been realized that these nanoantennas could be an efficient agent for the early detection of disease. Furthermore, for the marker detection, the heterodimeric nanogap, created between a nanostar antenna tip and a gold nanosphere, was seen to be more effective than those single nanostar antennas because of their higher intensity enhancement capability and also the optimum electric field map at the hot-spots which acts as the binding site for molecule. Both the AuNS antenna and the hybrid one could be easily converted to a biosensor, by anchoring suitable anti-bodies on the surface of the nanoantenna. Surprisingly, these gold nanostar antennas were seen to have both the non-edge breathing modes and the well-known edge dipolar mode. The optically active edge dipolar mode will be useful for the detection of protein molecules by using their localized surface plasmon resonance (LSPR) effect which is same as any conventional plasmonic biosensor. But the non-edge breathing modes of nanostar antenna will be helpful to determine the mass of adsorbed analyte based on the cantilever principle. The mass estimation (having the information about the polarizability and the size) of the markers is very crucial because it would provide the information about the number of amino acids present in that molecule which will help for better understanding of its molecular structure and thus will be useful for designing its anti-agent. This efficient acousto-plasmonic nanoantenna therefore could become a key element at a point of care. To go one step forward in this research area, Fano-lineshape based sensing was thought to be a promising idea. Here the reported Fano line-shape arises from the coupling of the gold nanorods dipped in thermo-responsive polymer matrix and a silver thin film. The Fano system was seen to respond to both the change in external temperature and the refractive index. This kind of Fano system will be helpful for the label-free detection of the foreign protein molecule with high efficiency and also for identifying the marker’s thermodynamic state and reactions of the molecule which is crucial for protein engineering. All these constitute the base of the discussion of part I of the thesis which is about the light harvesting plasmonic nanoantennas. In the 2nd part of the thesis, AZO metasurfaces and their optical activities are discussed. Aluminium doped Zinc Oxide (AZO) is a low-loss material and popular as an alternate plasmonic material. The highly ordered AZO nanotubes array system has seen to have gas sensing capability. The reported H2 gas detection within a very short time can make this system suitable for industrial application. The detection of H2 gas of lower concentration with the help of these nanostructures is also useful to detect the presence of bacteria by tasting their exhaled H2 gas. On the other hand, the AZO solid nanopillars arrays are seen to have generalized Brewster angle phenomena which can be useful for many applications including the optical switching. Lastly, some additional works have been described in a brief way. In this section, photonic nanojet related theoretical study, asymmetric sound transmission behaviour shown in 3D printed acoustics metamaterials, focal-length tunability of metalens and plasmon assisted cancer therapy has been reported. As per my belief and understanding, all these studies reported in this thesis will enrich the related research areas.
Active plasmonics in soft matter doped with gold nanoparticles plasmonica attiva in materia soffice drogata con nanoparticelle d'oro
(2013-11-29) Cataldi, Ugo; Bartolino, Roberto; Caputo, Roberto; Versace, Carlo C.
The main objective of this study is active plasmonics. The work has been focussed on the design, characterization and theoretical interpretation of novel systems. Top-down and bottom-up, self-assembling, approaches have been utilized to realize devices where spherical gold nanoparticles have been periodically and randomly arranged. Two main paths have been followed to achieve this goal. In the first one, by utilizing a rigid periodic structure as a host platform for soft-matter (cholesteric liquid crystals) mixed with plasmonic nano-entities, was possible to obtain a chirally-organized tuneable plasmonic system. The tunability of the obtained device has been induced by applying temperature changes or external electric fields. In the second one, the surface of an elastomeric platform has been randomly covered by gold-nanoparticles. Controlled nano-chemistry processes have been successively applied to the nanoparticles (immobilized on the surface) to locally increase their size. The elastic properties of the template together with the increased size of particles have allowed a systematic study of the coupling between near-fields of the spherical nanostructures. Colloidal nano-chemistry technics have been utilized both to synthetize spherical gold nano-particles and to increase their sizes. Spectroscopic analysis has been used to analyse the response of obtained structures under electrical, thermodynamical and mechanical stimuli. SEM and TEM imaging have been exploited to study the morphology of devices, the shape of nano-structures and to measure their sizes. Moreover, from SEM images, through the use of a MatLab code written to the purpose, it has been possible to extract fundamental parameters used to perform a theoretical analysis of experimental results
Advanced linear beam models to be exploited in the implicit corotational framework and FEM implementation
(2012-10-29) Genoese, Alessandra; Bartolino, Roberto; Casciaro, Raffaele; Garcea, Giovanni; Bilotta, Antonio
Università degli Studi della Calabria
Advanced Materials (Ceramics in particular) for Structural Applications
(2015-12-15) Koduru, Hari Krishna; Bartolino, Roberto; Versace, Carlo; Scaramuzza, Nicola
The study of ‘Intrinsic and Metal nano particles doped polymer thin films for soft matter applications and nanostructured Hyperbolic metamaterials’ is an challenging and dynamic field of research with significant implications in the development of novel technologies, like gas sensors, bio-medical application and engineering of spontaneous emission of florescent molecules. In the present investigation, we presented research work in two directions. We prepared Polymer thin films by homemade Cold Plasma Polymerization technique and studied their Microstructural, Optical and dielectric responses as a function of thin film growth parameters, in view of gas sensor applications. In other direction, we fabricated lamellar structured Hyperbolic Metamaterials by employing physical and chemical vapour thin film deposition techniques and employed them as effective substrates to engineer the life time of florescent dye molecules. The first part of this thesis is devoted to preparing Polypyrrole (PPy) thin films of nano sized thickness, by Cold plasma polymerization technique and analyzing the influence of Plasma power on Microstructural, Optical, wetting and dielectric properties of grown PPy films. Fabricating layered structures of “PVA/AgNPs/PVA” thin films to investigate the influence of rate of distribution of AgNPs on dielectric responses of PVA matrix to employ them as a gas sensor applications, whose study is still open and is getting substantial interest in industrial and academic environments. Enhancement of spontaneous emission is a dynamic and challenging fundamental quantum phenomenon in optics and in nutshell it opens new avenues for spectrum of futuristic applications. Metamaterials are artificially designed nanocomposite materials, in which bulk electromagnetic properties arise due to underlying structural resonances and near field coupling between the designed sub-wavelength building blocks. Metamaterials promise to alleviate the classical limitations of optics and led to exotic applications such as negative refraction, sub-wavelength resolution imaging, invisibility devices and perfect absorbers. In the second part of this thesis, we fabricated Hyperbolic metamaterials and proposed new grating coupled hyperbolic metamaterial (GCHMM) configuration for the enhancement of spontaneous emission rate of dye molecules by exploiting the unique property of a hypergrating to outcouple and extract the non-radiative plasmonic modes.
Advanced numerical models for highly frustrated liquid crystalline phases
(2014-11-03) de Jesus, Caldera Teresita; Bartolino, Roberto; Versace, Carlo C.; Barberi, Riccardo; Lombardo, Giuseppe
Aggregate structures analysis of bitumen for the production of modified benders in asphalt industry
(2013-12-02) Filippelli, Luigi; Bartolino, Roberto; Oliviero Rossi, ,Cesare
Since antiquity bitumen had been used as a construction material. Nowadays, most of the huge global production of bitumen each year, are functional to the roads paving industry where they are employed as binders for mineral aggregates to produce asphalt mixes. In the paving industry, a suitable bitumen should be fluid enough at to be pumpable and workable for a uniform covering of the mineral aggregates upon amalgamation. Furthermore, once the asphalt has been laid to build the roads, bitumen has to become sufficiently rigid at the highest pavement temperature to oppose rutting, depending on local climate conditions. Conversely, it must stay flexible enough at the lowest pavement temperature to resist cracking. For these purposes, additives such as polymers, acids, etc., are used to calibrate the operative range of bitumen. In addition asphalt industry is interested to reduce the costs of production, the environmental impact of the production and the safety condition for the paving workers. Bitumen is currently modeled as a dispersion of colloidal particles of asphaltenes, surrounded by a layer of stabilizing polar resins in a continuous oil phase (maltene). Although one can write a very simple definition of bitumen, its chemical composition is very complex and still not completely known. However the characterization of the bituminous materials for its convenient application, is still made by empirical standardized tests. This research project aimed to the deeper understanding of the behavior of bituminous systems, in order to correlate the macroscopic properties to the microstructure of the aggregates that constitute the bitumen colloidal network. We explored the possibility of taking advantage from chemical-physics techniques such as NMR, Rheology and AFM. In particular we have investigated the effect and overall the mechanism through which some chemical additives, already in use by paving companies, explicate their action to modulate the bitumen performances. Several samples different in nature and differently modified were analyzed. The rheological analysis, performed by the measurements under kinematic and dynamic control, helped to determine the material properties related to the structure of the system. The parameters thus obtained, being independent of the measurement conditions may be correlated with the microstructure of the sample investigated by the other techniques we used. As for NMR we exploited the spin-spin relaxation time measurement firstly to find the soften point of bituminous materials whether modified or not. As a novel approach to the understanding of the colloidal nature of the bitumen, the Inverse Laplace Transform (ILT) of the NMR spin-echo decay (T2) was applied. The ILT was used to draw the map of the macro-aggregates inside bitumen at different temperatures providing indication on the nature of the interaction between additives and the colloidal network. The efficiency of the ILT method was proved by atomic force microscopy images. As matter of fact collecting the AFM analysis, the ILT and the rheological results, we were able to describe the correlation between the aggregates at supra-molecular level inside fresh and doped bitumen. This research constituted a new inside bitumen chemistry overcoming the limits of the empirical tests to verify the efficiency of the bitumen modifiers
Astroparticle physics as a telescope for solar interior, galactic and extragalactic structures
(2013-11-25) D'Alessi, Loris; Bartolino, Roberto; Carbone, Vincenzo
Astroparticle physics provide a fundamental tool to investigate the astrophysical structures at different scales. In this thesis the results are presented of three years of research focused on time variations on solar neutrino flux, galactic cosmic rays and fine-structure constant as observed from quasar spectra. These topics are nowadays crucial to investigate structures which otherwise result difficult to probe. In particular time variations in solar neutrinos can give a real time description of the dynamics which take place in the inner regions of the Sun, while the study of galactic cosmic rays through the observation of muons produced by the interaction of the formers with the atmosphere, may give us precious informations on the interaction between TeV particles and heliospheric magnetic fields. Finally the recent observations of variations in the fine-structure constant value from the analysis of quasar absorption spectra, offer new possibilities to probe physical laws at cosmological scales. The thesis is structured as follows. In Chapter One are discussed quasi-biennial oscillations observed on solar neutrino flux and a phenomenological model is proposed to interpret the observed time variations. In the scenario described by the model, the interaction between solar neutrinos and solar matter mediated by magnetogravity modes, is modulated by a background magnetic field varying in time on quasi-biennial time scales. In Chapter Two the 11-yr component recently observed in cosmic muon data from Gran Sasso experiments of MACRO, LVD and Borexino has been reconstructed through the EMD analysis technique. In Chapter Three the data of fine-structure constant variations as observed in the quasar absorption spectra have been analyzed to search for temporal coherent structures. The thesis is completed by the description in appendix of a new algorithm based on Monte Carlo methods to assign a confidence interval to the IMFs extracted with the EMD analysis, and the application of this method to study the proton and neutrino distributions used in the OPERA experiment for the neutrino velocity measurement. Another appendix is dedicated to detailed description of the effects induced on the magnetogravity spectrum by a background magnetic field with a low-pass bandwidth, thus generalizing the theory of magneto-gravity modes in presence of a time-dependent background magnetic field.
Atomic forcemicroscopy of corneal biomechanics
(2014-11-28) Labate, Cristina; Bartolino, Roberto; Versace, Carlo; Barberi, Riccardo; De Santo, Maria P.
Behavior and effects of additives in liquid crystal compounds
(2011-11-03) Vivacqua, Marco; Bartolino, Roberto; Versace, Carlo; Nicoletta, Fiore P.
Bio-medicinal applications of coordination compounds: a photophysical point of view
(2012-11-26) Ricciardi, Loredana; Russo, Nino; La Deda, Massimo; Bartolino, Roberto
Il presente lavoro di ricerca, svolto presso il Laboratorio di Chimica Inorganica e di Coordinazione (LaCIC) dell'Università della Calabria, sotto la supervisione del Dott. Massimo La Deda, e in parte nel Laboratoire de Physico-Chimie des Matériaux Luminescents (Université Claude Bernard, Lyon, France), si colloca all'interfaccia tra la Biomedicina, la Chimica di Coordinazione e la Fotochimica, alla ricerca di un comune denominatore. L'obiettivo del nostro lavoro è stato quello di sviluppare una metodologia ed un set-up sperimentale per collegare l'esperienza del LaCIC nella sintesi organometallica, con le applicazioni di composti di coordinazione in campo biomedico. Abbiamo scelto tre aree di ricerca in grado di mettere in evidenza la relazione tra "composti di coordinazione", "luce" e "biomedicina": l'applicazione di complessi metallici incapsulati in polimeri o in nanoparticelle di oro e silice per la generazione di ossigeno di singoletto nella Terapia Fotodinamica (Capitoli 3 e 4), l'utilizzo dei processi a trasferimento di energia che coinvolgono i composti di coordinazione per lo studio delle interazioni farmaco-proteina (applicazioni di “sensing”, capitolo 2), l'utilizzo della luminescenza di nanoparticelle contenenti complessi di metalli di transizione nell’imaging cellulare. Le proprietà uniche dei composti metallici, soprattutto la rilevante fotochimica e fotofisica dei composti di metalli di transizione, li rendono idonei per applicazioni in fotomedicina. Capitolo 2 - Applicazione di “sensing” dei composti di coordinazione: interazione farmaco-proteina. Un nuovo complesso di zinco, recentemente sintetizzato presso il LaCIC, ha evidenziato un’interessante attività antiproliferativa in vitro nei confronti di alcune linee cellulari tumorali. Tuttavia, i test in vitro rappresentano solo il primo step per l’applicazione di questo complesso come farmaco antineoplastico; una fase successiva richiede uno studio della sua biodistribuzione, dunque la sua interazione con biomolecole quali l’ Albumina sierica umana, la proteina più abbondante presente nel torrente circolatorio, la quale aumenta la solubilità di farmaci idrofobici nel plasma e ne modula il rilascio a livello cellulare. Grazie alla fluorescenza della proteina, è stato possibile studiarne il fenomeno di quenching della luminescenza, correlandolo all’interazione di legame con il complesso metallico. Inoltre, la "struttura speciale" del composto di coordinazione, la sua luminescenza intrinseca, ha reso possibile lo studio dell’interazione di legame da un’altra prospettiva, giungendo ad una interessante conclusione, che evidenzia l'aspetto multifattoriale del complesso: terapeutico e sensoristico. Capitolo 3 - Processi attivati dalla luce in composti di coordinazione: fotogenerazione di ossigeno di singoletto. La Terapia Fotodinamica (PDT) fa riferimento all’applicazione di luce al fine di ottenere un effetto terapeutico, in particolare fa riferimento alla capacità di fotogenerare 1O2, una specie altamente reattiva (il “vero” agente terapeutico) da una molecola cosiddetta “fotosensibilizzante”. Tra gli effetti terapeutici dell’ 1O2 si pongono in evidenza la terapia antimicrobica e, soprattutto, la terapia antitumorale: in entrambe è preferibilmente richiesto l’utilizzo di fotosensibilizzanti solubili in acqua. I Complessi di Metalli di Transizione (TMC), grazie alle loro “speciali” proprietà fotofisiche, sono fotosensibilizzanti eccellenti, ma per la maggior parte scarsamente idrofilici. Per rendere TMC solubili in acqua si può procedere per esempio inserendoli in un polimero biocompatibile, senza che gli stessi perdino la loro capacità di generare ossigeno di singoletto. Seguendo questo criterio, è stato sintetizzato e caratterizzato il primo esempio di un polimero solubile in acqua legante un complesso di Pt(II) in grado di generare ossigeno di singoletto. Capitolo 4 - Il paradigma “theranostic”: complessi di metalli di transizione e nanoparticelle. Un’altra alternativa per ottenere un fotosensibilizzante solubile in acqua con le “speciali” proprietà dei TMC è di incapsularlo all’interno di nanoparticelle (NPs), le quali stanno sempre più acquisendo una crescente importanza in ambito medico, grazie alla capacità di agire da sistema di rilascio e alla loro bassa tossicità. Su questa base, sono state sintetizzate e caratterizzate un certo numero di NPs aventi un “core” d’oro e una “shell” di silice con intrappolati nella matrice complessi di Ir (III) e Ru (II), aventi la capacità di generare ossigeno di singoletto. Come prova preliminare, un campione di NPs contenenti un complesso di Ru (II), è stato caratterizzato in vitro per valutarne la citotossicità in diverse linee di cellule tumorali, con risultati promettenti. Inoltre, le "speciali" proprietà fotofisiche dei TMC consentono una disattivazione non radiativa degli stati eccitati (fenomeno necessario per la generazione di 1O2 mediante un processo a trasferimento di energia) senza perdere la luminescenza. In virtù di questo, è stato possibile localizzare le NPs fotosensibilizzanti all'interno della cellula mediante microscopia a fluorescenza, rendendo le NPs sintetizzate un nuovo materiale per “theranostic purposes”.
Boundary element analysis of composite materials
(2014-10-31) Vetere, Ferdinando; Bartolino, Roberto; Zinno, Raffaele
Nowdays the numerical simulation of mechanical and structural problems in engineering is the method of analysis and design more widespread. Compared to the use of analytical solutions, the numerical simulation is characterized by a great exibility, due to the possibility to analyze complex geometries and models. The possibility of nding exact solutions are limited to one-dimensional problems or problems with multiple variables with special symmetries. In the context of the problems of linear elasticity, the situation of isotropic material simpli es the analysis in closed form for the presence of only two elastic coef- cients in the constitutive equations. Recently, the interest for the analysis of problems with non-isotropic constitutive equations has been renewed by the availability of new materials suitable for the production of structural elements. In particular, the technical interest in the case of materials with orthotropic constitutive equations. This work is about the analytical solution of the plane problem for orthotropic materials using a model based on the discretization of the boundary. In order to de ne the context of the model developed, there is a brief introduction about the method of boundary elements and some considerations on the use of orthotropic materials in structural elements.
Cancellation analysis in turbulent plasmas: from numerical silumations to solar active regions
(2013-11-27) De Vita, Gaetano; Bartolino, Roberto; Sorriso Valvo, Luca
Combined use of X-ray Fluorescence Microscopy, X-ray Phase Contrast Imaging, Atomic Force Microscopy and X-ray Nanotomography for high resolution quantitative Fe mapping in inflamed cells.
(2017-07-17) Gramaccioni, Chiara; Carbone, Vincenzo; Lagomarsino, Stefano; Bartolino, Roberto
The PhD project is based on the applications of several x-ray microscopy techniques for compositional and morphological studies at nanoscale spatial resolution to a biological problem, i.e. the quantitative determination of morphological and compositional properties of epithelial cells. Three x-ray microscopy techniques were exploited in this work: X-ray fluorescence microscopy, X-ray phase contrast imaging and nanotomography, which were made at the ID16NI beamline of the European Synchrotron Radiation Facility in Grenoble, France. In addition to synchrotron-based techniques, also Atomic Force Microscopy was performed. The latter was used for morphology characterization, and forcalibration and comparison purpose. The main aim of this study was to quantitatively determine the map of iron concentration at nanoscale spatial resolution of epithelial cells infected by bacterial pathogens in the presence or absence of lactoferrin (Lf), an iron-chelating glycoprotein of natural immunity. Two experiments have been carried out at ESRF, one on freeze dried cells, and one on frozen hydrated cells this last using the cryo stage foreseen in the Id16 NI beamline, in order to examine cells as close as possible to their native state, and to avoid radiation damage. The measurement and data analysis protocols have been carefully studied for optimal combination of all the techniques, to give quantitative results. Iron concentration and mass fraction maps have been obtained, which give an insight about the modification of iron spatial distribution under the influence of lactoferrin. Moreover, for the first time it has been demonstrated the possibility to obtain quantitative element concentration in cells through the combination of x-ray nanotomography in phase contrast and x-ray fluorescence microscopy.
Complexity in climate
(2012-12-25) Capparelli, Vincenzo; Bartolino, Roberto; Carbone, Vincenzo
Design, synthesis and characterization of suitable nitrones for several synthetic applications
(2013-11-21) Melicchio, Alessandro; Bartolino, Roberto; Gabriele, Bartolo; Maiuolo, Loredana
The present work takes advance of nitrone chemistry flexibility in order to synthesize, on one hand, bisphosphonates containing N,O-carbocyclic nucleoside units with potential biological activity, starting from nitrones with functionalizable ester or methylen bisphosphonated groups. On the other hand, to synthesize suitable allyl cyclic nitrones undergoing 2-aza-Cope rearrangement in order to study the [3,3]-sigmatropic process that has been rarely detected until now with neutral molecules which are nitrones. The synthetic strategy that we used for the bisphosphonates compound involves the synthesis of suitable nitrones and subsequently 1,3-dipolar cycloaddition reaction between these substrates and various vinyl nucleobases that carries at formation of isoxazolidinyl nucleosides. We decided to synthesize them for their significant pharmacological properties that make them very appealing: they showed a considerable cytotoxic activity against several human cell lines and therefore they could be successfully employed as anticancer drugs. Furthermore, bisphosphonates can be considered as stable analogs of pyrophosphate, that is implied in the physiological regulation of bone calcification and resorption. Moreover, during the staying at the University of Zaragoza in Spain, a synthesis of suitable cyclic allyl nitrones was carried out. In general aza-Cope rearrangements have attracted great interest because of the ubiquitous presence of nitrogen-containing structures in natural and biological products as well as synthetic intermediates. These compounds give rise to 2-aza-Cope rearrangement and we reported a full experimental study based on NMR kinetic experiments of the activation energies required for both neutral and catalyzed 2-aza- Cope rearrangements of nitrones
Development and optimization by experimental design of solid phase microextraction gas chromatography triple quadrupole mass spectrometry methods in aqueous matrices
(2012-11-30) Monteleone, Marcello; Tagarelli, Antonio; Gabriele, Bartolo; Bartolino, Roberto
Il presente lavoro di tesi relativo all‘attività di ricerca svolta durante il triennio di dottorato ha riguardato la messa a punto di metodi analitici per la determinazione di analiti in due distinte aree di interesse. La prima di ambito clinico ed ha riguardato la quantificazione in urina di metaboliti riconosciuti come marker in diagnostica clinica. In particolare ci si occupati della sarcosina come biomarker del tumore alla prostata, e di tre acidi: acido omovanillico (HVA), acido vanilmandelico (VMA) ed acido 5-idrossindoloacetico (5-HIAA) come marker urinari del neuroblastoma. Il secondo ambito di lavoro ha riguardato la quantificazione di inquinanti in matrici acquose, vale a dire carbammati ed acidi perfluoroalchilici. In particolare gli analiti, previa derivatizzazione con alchilcloroformiati (eccetto i carbammati), sono stati estratti dalle matrici acquose (acqua e urina) tramite la tecnica della microestrazione in fase solida (SPME) e successivamente analizzati mediante un gascromatografo con analizzatore di massa a triplo quadrupolo (GC-QqQ-MS). Le variabili significative della microestrazione in fase solida in ciascun metodo sono state ottimizzate tramite l‘approccio multivariato dell‘ ― Experimental Design‖. L‘utilizzo della tecnica SPME ha consentito di poter estrarre gli analiti direttamente dal campione da analizzare minimizzando i tempi di preparazione dello stesso e riducendo l‘uso di solventi organici, ottenendo metodi poco costosi e basso impatto ambientale. L‘utilizzo dello spettrometro di massa triplo quadrupolo, ha consentito di raggiungere livelli di sensibilità molto elevati e, nel contempo, di identificare gli analiti con maggiore sicurezza. In tutti i metodi sviluppati, sono stati ottenuti ottimi risultati in termini di linearità accuratezza e precisione. Anche i valori dei limiti di rilevabilità (LOD) e dei limiti di quantificazione (LOQ) ottenuti in ciascun metodo possono essere considerati soddisfacenti.
Development of cycloisomerization reactions for the synthesis of nitrogen or oxygen containing heterocycles
(2011-10-26) Spina, Rosella; Bartolino, Roberto; Gabriele, Bartolo; Salerno, Giuseppe; Colacino, Evelina