Electrochemistry of carbon based engineered structures

The main aims of my PhD research work have been the investigation of the redox, photophysical and electronic properties of carbon nanotubes (CNT) and their possible uses as functional substrates for the (electro)catalytic production of oxygen and as molecular connectors for Quantum-dot Molecular Automata. While for CNT many and diverse applications in electronics, in sensors and biosensors field, as a structural reinforcing in composite materials have long been proposed, the study of their properties as individual species has been for long a challenging task. CNT are in fact virtually insoluble in any solvent and, for years, most of the studies has been carried out on bulk samples (bundles). In Chapter 2 an appropriate description of carbon nanotubes is reported, about their production methods and the functionalization strategies for their solubilization. In Chapter 3 an extensive voltammetric and vis-NIR spectroelectrochemical investigation of true solutions of unfunctionalized individual single wall CNT (SWNT) is reported that permitted to determine for the first time the standard electrochemical potentials of reduction and oxidation as a function of the tube diameter of a large number of semiconducting SWNTs. We also established the Fermi energy and the exciton binding energy for individual tubes in solution and, from the linear correlation found between the potentials and the optical transition energies, one to calculate the redox potentials of SWNTs that are insufficiently abundant or absent in the samples. In Chapter 4 we report on very efficient and stable nano-structured, oxygen-evolving anodes (OEA) that were obtained by the assembly of an oxygen evolving polyoxometalate cluster, (a totally inorganic ruthenium catalyst) with a conducting bed of multiwalled carbon nanotubes (MWCNT). Here, MWCNT were effectively used as carrier of the polyoxometallate for the electrocatalytic production of oxygen and turned out to greatly increase both the efficiency and stability of the device avoiding the release of the catalysts. Our bioinspired electrode addresses the major challenge of artificial photosynthesis, i.e. efficient water oxidation, taking us closer to when we might power the planet with carbon-free fuels. In Chapter 5 a study on surface-active chiral bis-ferrocenes conveniently designed in order to act as prototypical units for molecular computing devices is reported. Preliminary electrochemical studies in liquid environment demonstrated the capability of such molecules to enter three indistinguishable oxidation states. Side chains introduction allowed to organize them in the form of self-assembled monolayers (SAM) onto a surface and to study the molecular and redox properties on solid substrates. Electrochemical studies on SAMs of these molecules confirmed their attitude to undergo fast (Nernstian) electron transfer processes generating, in the positive potential region, either the full oxidized Fc+-Fc+ or the partly oxidized Fc+-Fc species. Finally, in Chapter 6 we report on a preliminary electrochemical study of graphene solutions prepared according to an original procedure recently described in the literature. Graphene is the newly-born of carbon nanomaterials and is certainly bound to be among the most promising materials for the next nanoelectronic generation.

Troposphere Calibration Techniques for Deep Space Probe Tracking

Ground-based Earth troposphere calibration systems play an important role in planetary exploration, especially to carry out radio science experiments aimed at the estimation of planetary gravity fields. In these experiments, the main observable is the spacecraft (S/C) range rate, measured from the Doppler shift of an electromagnetic wave transmitted from ground, received by the spacecraft and coherently retransmitted back to ground. If the solar corona and interplanetary plasma noise is already removed from Doppler data, the Earth troposphere remains one of the main error sources in tracking observables. Current Earth media calibration systems at NASA’s Deep Space Network (DSN) stations are based upon a combination of weather data and multidirectional, dual frequency GPS measurements acquired at each station complex. In order to support Cassini’s cruise radio science experiments, a new generation of media calibration systems were developed, driven by the need to achieve the goal of an end-to-end Allan deviation of the radio link in the order of 3×〖10〗^(-15) at 1000 s integration time. The future ESA’s Bepi Colombo mission to Mercury carries scientific instrumentation for radio science experiments (a Ka-band transponder and a three-axis accelerometer) which, in combination with the S/C telecommunication system (a X/X/Ka transponder) will provide the most advanced tracking system ever flown on an interplanetary probe. Current error budget for MORE (Mercury Orbiter Radioscience Experiment) allows the residual uncalibrated troposphere to contribute with a value of 8×〖10〗^(-15) to the two-way Allan deviation at 1000 s integration time. The current standard ESA/ESTRACK calibration system is based on a combination of surface meteorological measurements and mathematical algorithms, capable to reconstruct the Earth troposphere path delay, leaving an uncalibrated component of about 1-2% of the total delay. In order to satisfy the stringent MORE requirements, the short time-scale variations of the Earth troposphere water vapor content must be calibrated at ESA deep space antennas (DSA) with more precise and stable instruments (microwave radiometers). In parallel to this high performance instruments, ESA ground stations should be upgraded to media calibration systems at least capable to calibrate both troposphere path delay components (dry and wet) at sub-centimetre level, in order to reduce S/C navigation uncertainties. The natural choice is to provide a continuous troposphere calibration by processing GNSS data acquired at each complex by dual frequency receivers already installed for station location purposes. The work presented here outlines the troposphere calibration technique to support both Deep Space probe navigation and radio science experiments. After an introduction to deep space tracking techniques, observables and error sources, in Chapter 2 the troposphere path delay is widely investigated, reporting the estimation techniques and the state of the art of the ESA and NASA troposphere calibrations. Chapter 3 deals with an analysis of the status and the performances of the NASA Advanced Media Calibration (AMC) system referred to the Cassini data analysis. Chapter 4 describes the current release of a developed GNSS software (S/W) to estimate the troposphere calibration to be used for ESA S/C navigation purposes. During the development phase of the S/W a test campaign has been undertaken in order to evaluate the S/W performances. A description of the campaign and the main results are reported in Chapter 5. Chapter 6 presents a preliminary analysis of microwave radiometers to be used to support radio science experiments. The analysis has been carried out considering radiometric measurements of the ESA/ESTEC instruments installed in Cabauw (NL) and compared with the requirements of MORE. Finally, Chapter 7 summarizes the results obtained and defines some key technical aspects to be evaluated and taken into account for the development phase of future instrumentation.

Advanced lithium and lithium-ion rechargeable batteries for automotive applications

The worldwide demand for a clean and low-fuel-consuming transport promotes the development of safe, high energy and power electrochemical storage and conversion systems. Lithium-ion batteries (LIBs) are considered today the best technology for this application as demonstrated by the recent interest of automotive industry in hybrid (HEV) and electric vehicles (EV) based on LIBs. This thesis work, starting from the synthesis and characterization of electrode materials and the use of non-conventional electrolytes, demonstrates that LIBs with novel and safe electrolytes and electrode materials meet the targets of specific energy and power established by U.S.A. Department of Energy (DOE) for automotive application in HEV and EV. In chapter 2 is reported the origin of all chemicals used, the description of the instruments used for synthesis and chemical-physical characterizations, the electrodes preparation, the batteries configuration and the electrochemical characterization procedure of electrodes and batteries. Since the electrolyte is the main critical point of a battery, in particular in large- format modules, in chapter 3 we focused on the characterization of innovative and safe electrolytes based on ionic liquids (characterized by high boiling/decomposition points, thermal and electrochemical stability and appreciable conductivity) and mixtures of ionic liquid with conventional electrolyte. In chapter 4 is discussed the microwave accelerated sol–gel synthesis of the carbon- coated lithium iron phosphate (LiFePO 4 -C), an excellent cathode material for LIBs thanks to its intrinsic safety and tolerance to abusive conditions, which showed excellent electrochemical performance in terms of specific capacity and stability. In chapter 5 are presented the chemical-physical and electrochemical characterizations of graphite and titanium-based anode materials in different electrolytes. We also characterized a new anodic material, amorphous SnCo alloy, synthetized with a nanowire morphology that showed to strongly enhance the electrochemical stability of the material during galvanostatic full charge/discharge cycling. Finally, in chapter 6, are reported different types of batteries, assembled using the LiFePO 4 -C cathode material, different anode materials and electrolytes, characterized by deep galvanostatic charge/discharge cycles at different C-rates and by test procedures of the DOE protocol for evaluating pulse power capability and available energy. First, we tested a battery with the innovative cathode material LiFePO 4 -C and conventional graphite anode and carbonate-based electrolyte (EC DMC LiPF 6 1M) that demonstrated to surpass easily the target for power-assist HEV application. Given that the big concern of conventional lithium-ion batteries is the flammability of highly volatile organic carbonate- based electrolytes, we made safe batteries with electrolytes based on ionic liquid (IL). In order to use graphite anode in IL electrolyte we added to the IL 10% w/w of vinylene carbonate (VC) that produces a stable SEI (solid electrolyte interphase) and prevents the graphite exfoliation phenomenon. Then we assembled batteries with LiFePO 4 -C cathode, graphite anode and PYR 14 TFSI 0.4m LiTFSI with 10% w/w of VC that overcame the DOE targets for HEV application and were stable for over 275 cycles. We also assembled and characterized ―high safety‖ batteries with electrolytes based on pure IL, PYR 14 TFSI with 0.4m LiTFSI as lithium salt, and on mixture of this IL and standard electrolyte (PYR 14 TFSI 50% w/w and EC DMC LiPF 6 50% w/w), using titanium-based anodes (TiO 2 and Li 4 Ti 5 O 12 ) that are commonly considered safer than graphite in abusive conditions. The batteries bearing the pure ionic liquid did not satisfy the targets for HEV application, but the batteries with Li 4 Ti 5 O 12 anode and 50-50 mixture electrolyte were able to surpass the targets. We also assembled and characterized a lithium battery (with lithium metal anode) with a polymeric electrolyte based on poly-ethilenoxide (PEO 20 – LiCF 3 SO 3 +10%ZrO 2 ), which satisfied the targets for EV application and showed a very impressive cycling stability. In conclusion, we developed three lithium-ion batteries of different chemistries that demonstrated to be suitable for application in power-assist hybrid vehicles: graphite/EC DMC LiPF 6 /LiFePO 4 -C, graphite/PYR 14 TFSI 0.4m LiTFSI with 10% VC/LiFePO 4 -C and Li 4 T i5 O 12 /PYR 14 TFSI 50%-EC DMC LiPF 6 50%/LiFePO 4 -C. We also demonstrated that an all solid-state polymer lithium battery as Li/PEO 20 –LiCF 3 SO 3 +10%ZrO 2 /LiFePO 4 -C is suitable for application on electric vehicles. Furthermore we developed a promising anodic material alternative to the graphite, based on SnCo amorphous alloy.

Analisi di “Copy Number Variants” ed identificazione di nuovi geni candidati per l’Autismo e Ritardo Mentale

I disturbi dello spettro autistico (DSA) ed il ritardo mentale (RM) sono caratterizzati da un’eziologia genetica complessa ed eterogenea. Grazie ai recenti sviluppi nella ricerca genomica, è stato possibile dimostrare il ruolo di numerose copy number variants (CNVs) nella patogenesi di questi disturbi, anche se nella maggior parte dei casi l’eziologia rimane ancora sconosciuta. Questo lavoro riguarda l’identificazione e la caratterizzazione dei CNVs in famiglie con DSA e RM. E’ stata studiata una microdelezione in 7q31 che coinvolge i geni IMMP2L e DOCK4, trasmessa dalla madre con dislessia a due figli con autismo ed una figlia con dislessia. Nella stessa famiglia segrega una seconda microdelezione in 2q14 che inattiva il gene CNTNAP5 ed è trasmessa dal padre (con tratti autistici) ai due figli con autismo. Abbiamo quindi ipotizzato che i geni DOCK4 e CNTNAP5 potessero essere implicati, rispettivamente, nella suscettibilità a dislessia e DSA. Lo screening di numerosi individui affetti ha supportato la nostra ipotesi, con l’identificazione di una nuova microdelezione di DOCK4 che segrega con la dislessia, e 3 nuove varianti missenso in CNTNAP5 in individui con autismo. Dall’analisi genomica comparativa su array (aCGH) di individui con RM, è stata identificata una delezione nella regione 7q31.32, che coinvolge il gene CADPS2, in due fratelli con RM e tratti autistici, probabilmente ereditata dalla madre. Lo screening di mutazione di questo gene in individui con autismo o RM, ha portato all’identificazione di 3 varianti non sinonime, assenti nei controlli, ed ereditate per via materna. Poiché CADPS2 risiede in una regione genomica che contiene loci soggetti ad imprinting, abbiamo ipotizzato che il gene CADPS2 possa essere anch’esso caratterizzato da imprinting, con espressione monoallelica materna. Lo studio di espressione di CADPS2 in cellule del sangue ha avvalorato questa ipotesi, implicando perciò CADPS2 come un nuovo gene di suscettibilità per il RM e DSA.

Progettualità e interventi educativi nella dislessia. Il progetto ProDSA e le prospettive future di ricerca.

Il presente lavoro è strutturato in quattro parti analizzando e comparando le pubblicazioni del settore scientifico italiano, anglofono e tedesco di riferimento. Nel primo capitolo della tesi viene proposta una riflessione sulle parole che ruotano attorno al tema dei DSA e della disabilità. Nel secondo capitolo vengono presentati, a partire dalla letteratura scientifica di riferimento, gli indicatori di rischio che segnalano possibili disturbi specifici di apprendimento e le caratteristiche di apprendimento dei DSA mettendo in luce potenzialità e talenti spesso intrinseci. Nel terzo capitolo viene vagliata la normativa di riferimento, in particolare la recente Legge 170/2010 e le relative Linee Guida. Nel quarto capitolo, partendo dal tema della diffusione delle tecnologie dell’informazione e della comunicazione (da ora in poi TIC) nel mondo della scuola, sono ampiamente trattati i principali strumenti compensativi (sintesi vocale, libri digitali, mappe concettuali, Lavagna Interattiva Multimediale) e le misure dispensative adottabili. Nel quinto capitolo viene analizzato in tutte le sue parti il Piano Didattico Personalizzato (da ora in poi PDP) e viene proposto un possibile modello di PDP pubblicato sul sito dell'Ufficio per l’Ambito Territoriale di Bologna. Nel sesto capitolo della tesi viene presentato il Progetto Regionale ProDSA. Il Progetto, rivolto a studenti, con diagnosi di DSA, delle scuole secondarie di primo grado e del primo biennio delle secondarie di secondo grado dell’Emilia-Romagna, ha visto, grazie a un finanziamento della Regione, la consegna in comodato d'uso gratuito di tecnologie compensative agli alunni che hanno aderito. La sezione empirica del presente lavoro indaga l’uso reale che è stato fatto degli strumenti proposti in comodato d’uso e le motivazioni legate alla scelta di non utilizzarli in classe. Nel settimo capitolo vengono proposti strumenti progettati per rispondere concretamente alle criticità emerse dall'analisi dei dati e per sensibilizzare il mondo della scuola sulle caratteristiche dei DSA.

Glycomics as an innovative technology to identify biomarkers of aging

Introduction. Glycomic analysis allows investigating on the global glycome within body fluids (as serum/plasma), this could eventually lead to identify new types of disease biomarkers, or as in this study, biomarkers of human aging studying specific aging models. Recent studies demonstrated that the plasma N-glycome is modified during human aging, suggesting that measurements of log-ratio of two serum/plasma N-glycans (NGA2F and NA2F), named GlycoAge test could provide a non-invasive biomarker of aging. Down syndrome (DS) is a genetic disorder in which multiple major aspects of senescent phenotype occur much earlier than in healthy age-matched subjects and has been often defined as an accelerated aging syndrome. The aim of this study was to compare plasma N-glycome of patients affected by DS with age- and sex matched non-affected controls, represented by their siblings (DSS), in order to assess if DS is characterized by a specific N-glycomic pattern. Therefore, in order to investigate if N-glycans changes that occur in DS were able to reveal an accelerated aging in DS patients, we enrolled the mothers (DSM) of the DS and DSS, representing the non-affected control group with a different chronological age respect to DS. We applied two different N-glycomics approaches on the same samples: first, in order to study the complete plasma N-glycome we applied a new high-sensitive protocol based on a MALDI-TOF-MS approach, second, we used DSA-FACE technology. Results: MALDI-TOF/MS analysis detected a specific N-glycomics signature for DS, characterized by an increase of fucosylated and bisecting species. Moreover, in DS the abundance of agalactosylated (as NA2F) species was similar or higher than their mothers. The measurement of GlycoAge test with DSA-FACE, validated also by MALDI-TOF, demonstrated a strongly association with age, moreover in DS, it’s value was similar to their mothers, and significantly higher than their age- and sex matched not-affected siblings