Application of different instrumental techniques to the selective evaluation of bio-sensible compounds in foodstuff of animal and vegetable origin

This PhD thesis describes the application of some instrumental analytical techniques suitable to the study of fundamental food products for the human diet, such as: extra virgin olive oil and dairy products. These products, widely spread in the market and with high nutritional values, are increasingly recognized healthy properties although their lipid fraction might contain some unfavorable components to the human health. The research activity has been structured in the following investigations: “Comparison of different techniques for trans fatty acids analysis” “Fatty acids analysis of outcrop milk cream samples, with particular emphasis on the content of Conjugated Linoleic Acid (CLA) and trans Fatty Acids (TFA), by using 100m high-polarity capillary column” “Evaluation of the oxidited fatty acids (OFA) content during the Parmigiano-Reggiano cheese seasoning” “Direct analysis of 4-desmethyl sterols and two dihydroxy triterpenes in saponified vegetal oils (olive oil and others) using liquid chromatography-mass spectrometry” “Quantitation of long chain poly-unsatured fatty acids (LC-PUFA) in base infant formulas by Gas Chromatography, and evaluation of the blending phases accuracy during their preparation” “Fatty acids composition of Parmigiano Reggiano cheese samples, with emphasis on trans isomers (TFA)”

Bio-physical interactions and feedbacks in a global climate model

This PhD thesis addresses the topic of large-scale interactions between climate and marine biogeochemistry. To this end, centennial simulations are performed under present and projected future climate conditions with a coupled ocean-atmosphere model containing a complex marine biogeochemistry model. The role of marine biogeochemistry in the climate system is first investigated. Phytoplankton solar radiation absorption in the upper ocean enhances sea surface temperatures and upper ocean stratification. The associated increase in ocean latent heat losses raises atmospheric temperatures and water vapor. Atmospheric circulation is modified at tropical and extratropical latitudes with impacts on precipitation, incoming solar radiation, and ocean circulation which cause upper-ocean heat content to decrease at tropical latitudes and to increase at middle latitudes. Marine biogeochemistry is tightly related to physical climate variability, which may vary in response to internal natural dynamics or to external forcing such as anthropogenic carbon emissions. Wind changes associated with the North Atlantic Oscillation (NAO), the dominant mode of climate variability in the North Atlantic, affect ocean properties by means of momentum, heat, and freshwater fluxes. Changes in upper ocean temperature and mixing impact the spatial structure and seasonality of North Atlantic phytoplankton through light and nutrient limitations. These changes affect the capability of the North Atlantic Ocean of absorbing atmospheric CO2 and of fixing it inside sinking particulate organic matter. Low-frequency NAO phases determine a delayed response of ocean circulation, temperature and salinity, which in turn affects stratification and marine biogeochemistry. In 20th and 21st century simulations natural wind fluctuations in the North Pacific, related to the two dominant modes of atmospheric variability, affect the spatial structure and the magnitude of the phytoplankton spring bloom through changes in upper-ocean temperature and mixing. The impacts of human-induced emissions in the 21st century are generally larger than natural climate fluctuations, with the phytoplankton spring bloom starting one month earlier than in the 20th century and with ~50% lower magnitude. This PhD thesis advances the knowledge of bio-physical interactions within the global climate, highlighting the intrinsic coupling between physical climate and biosphere, and providing a framework on which future studies of Earth System change can be built on.

Chemical analysis and reactivity of biomass pyrolysis products. Application to the development of carbon-neutral biofuels and chemicals

In this dissertation the pyrolytic conversion of biomass into chemicals and fuels was investigated from the analytical point of view. The study was focused on the liquid (bio-oil) and solid (char) fractions obtainable from biomass pyrolysis. The drawbacks of Py-GC-MS described so far were partially solved by coupling different analytical configurations (Py-GC-MS, Py-GC-MIP-AED and off-line Py-SPE and Py-SPME-GC-MS with derivatization procedures). The application of different techniques allowed a satisfactory comparative analysis of pyrolysis products of different biomass and a high throughput screening on effect of 33 catalysts on biomass pyrolysis. As the results of the screening showed, the most interesting catalysts were those containing copper (able to reduce the high molecular weight fraction of bio-oil without large yield decrease) and H-ZSM-5 (able to entirely convert the bio-oil into “gasoline like” aromatic products). In order to establish the noxious compounds content of the liquid product, a clean-up step was included in the Py-SPE procedure. This allowed to investigate pollutants (PAHs) generation from pyrolysis and catalytic pyrolysis of biomass. In fact, bio-oil from non-catalytic pyrolysis of biomass showed a moderate PAHs content, while the use of H-ZSM-5 catalyst for bio-oil up-grading determined an astonishing high production of PAHs (if compared to what observed in alkanes cracking), indicating an important concern in the substitution fossil fuel with bio-oil derived from biomass. Moreover, the analytical procedures developed in this thesis were directly applied for the detailed study of the most useful process scheme and up-grading route to chemical intermediates (anhydrosugars), transportation fuels or commodity chemicals (aromatic hydrocarbons). In the applied study, poplar and microalgae biomass were investigated and overall GHGs balance of pyrolysis of agricultural residues in Ravenna province was performed. A special attention was put on the comparison of the effect of bio-char different use (fuel or as soil conditioner) on the soil health and GHGs emissions.

Advanced CMOS Interfaces for Bio-Nanosensors

The improvement of devices provided by Nanotechnology has put forward new classes of sensors, called bio-nanosensors, which are very promising for the detection of biochemical molecules in a large variety of applications. Their use in lab-on-a-chip could gives rise to new opportunities in many fields, from health-care and bio-warfare to environmental and high-throughput screening for pharmaceutical industry. Bio-nanosensors have great advantages in terms of cost, performance, and parallelization. Indeed, they require very low quantities of reagents and improve the overall signal-to-noise-ratio due to increase of binding signal variations vs. area and reduction of stray capacitances. Additionally, they give rise to new challenges, such as the need to design high-performance low-noise integrated electronic interfaces. This thesis is related to the design of high-performance advanced CMOS interfaces for electrochemical bio-nanosensors. The main focus of the thesis is: 1) critical analysis of noise in sensing interfaces, 2) devising new techniques for noise reduction in discrete-time approaches, 3) developing new architectures for low-noise, low-power sensing interfaces. The manuscript reports a multi-project activity focusing on low-noise design and presents two developed integrated circuits (ICs) as examples of advanced CMOS interfaces for bio-nanosensors. The first project concerns low-noise current-sensing interface for DC and transient measurements of electrophysiological signals. The focus of this research activity is on the noise optimization of the electronic interface. A new noise reduction technique has been developed so as to realize an integrated CMOS interfaces with performance comparable with state-of-the-art instrumentations. The second project intends to realize a stand-alone, high-accuracy electrochemical impedance spectroscopy interface. The system is tailored for conductivity-temperature-depth sensors in environmental applications, as well as for bio-nanosensors. It is based on a band-pass delta-sigma technique and combines low-noise performance with low-power requirements.

A chemical loop approach for methanol reforming

Over the past few years, the switch towards renewable sources for energy production is considered as necessary for the future sustainability of the world environment. Hydrogen is one of the most promising energy vectors for the stocking of low density renewable sources such as wind, biomasses and sun. The production of hydrogen by the steam-iron process could be one of the most versatile approaches useful for the employment of different reducing bio-based fuels. The steam iron process is a two-step chemical looping reaction based (i) on the reduction of an iron-based oxide with an organic compound followed by (ii) a reoxidation of the reduced solid material by water, which lead to the production of hydrogen. The overall reaction is the water oxidation of the organic fuel (gasification or reforming processes) but the inherent separation of the two semireactions allows the production of carbon-free hydrogen. In this thesis, steam-iron cycle with methanol is proposed and three different oxides with the generic formula AFe2O4 (A=Co,Ni,Fe) are compared in order to understand how the chemical properties and the structural differences can affect the productivity of the overall process. The modifications occurred in used samples are deeply investigated by the analysis of used materials. A specific study on CoFe2O4-based process using both classical and in-situ/ex-situ analysis is reported employing many characterization techniques such as FTIR spectroscopy, TEM, XRD, XPS, BET, TPR and Mössbauer spectroscopy.

Optimization of bioenergy solutions at different farm scales

RAF is a bio-energetic descriptive model integrates with MAD model to support Integrated Farm Management. RAF model aimed to enhancing economical, social and environmental sustainability of farm production in terms of energy via convert energy crops and animal manure to biogas and digestate (bio-fertilizers) by anaerobic digestion technologies, growing and breeding practices. The user defines farm structure in terms of present crops, livestock and market prices and RAF model investigates the possibilities of establish on-farm biogas system (different anaerobic digestion technologies proposed for different scales of farms in terms of energy requirements) according to budget and sustainability constraints to reduce the dependence on fossil fuels. The objective function of RAF (Z) is optimizing the total net income of farm (maximizing income and minimizing costs) for whole period which is considered by the analysis. The main results of this study refers to the possibility of enhancing the exploitation of the available Italian potentials of biogas production from on-farm production of energy crops and livestock manure feedstock by using the developed mathematical model RAF integrates with MAD to presents reliable reconcile between farm size, farm structure and on-farm biogas systems technologies applied to support selection, applying and operating of appropriate biogas technology at any farm under Italian conditions.

New catalytic processes for the upgrading of furfural and 5-hydroxymethylfurfural to chemicals and fuels

The demand of energy, fuels and chemicals is increasing due to the strong growth of some countries in the developing world and the development of the world economy. Unfortunately, the general picture derived sparked an exponential increase in crude oil prices with a consequent increase of the chemical, by-products and energy, depleting the global market. Nowadays biomass are the most promising alternative to fossil fuels for the production of chemicals and fuels. In this work, the development of three different catalytic processes for the valorization of biomass-derived has been investigated. 5-hydroxymethylfurfural oxidation was studied under mild reaction condition using gold and gold/copper based catalysts synthetized from pre-formed nanoparticles and supported onto TiO2 and CeO2. The analysis conducted on catalysts showed the formation of alloys gold/copper and a strong synergistic effect between the two metals. For this reason the bimetallic catalysts supported on titania showed a higher catalytic activity respect to the monometallic catalysts. The process for the production of 2,5-bishydroxymethyl furan (BHMF) was also optimized by means the 5-hydroxymethylfurfural hydrogenation using the Shvo complex. Complete conversion of HMF was achieved working at 90 °C and 10 bar of hydrogen. The complex was found to be re-usable for at least three catalytic cycles without suffering any type of deactivation. Finally, the hydrogenation of furfural and HMF was carried out, developing the process of hydrogen transfer by using MgO as a catalyst and methanol as a hydrogen donor. Quantitative yields to alcohols have been achieved in a few hours working in mild condition: 160 °C and at autogenous pressure. The only by-products formed were light products such as CO, CO2 and CH4 (products derived from methanol transformation), easily separable from the reaction solution depressurizing the reactor.

Hybrid portable systems for bio-nanosensors

The promising development in the routine nanofabrication and the increasing knowledge of the working principles of new classes of highly sensitive, label-free and possibly cost-effective bio-nanosensors for the detection of molecules in liquid environment, has rapidly increased the possibility to develop portable sensor devices that could have a great impact on many application fields, such as health-care, environment and food production, thanks to the intrinsic ability of these biosensors to detect, monitor and study events at the nanoscale. Moreover, there is a growing demand for low-cost, compact readout structures able to perform accurate preliminary tests on biosensors and/or to perform routine tests with respect to experimental conditions avoiding skilled personnel and bulky laboratory instruments. This thesis focuses on analysing, designing and testing novel implementation of bio-nanosensors in layered hybrid systems where microfluidic devices and microelectronic systems are fused in compact printed circuit board (PCB) technology. In particular the manuscript presents hybrid systems in two validating cases using nanopore and nanowire technology, demonstrating new features not covered by state of the art technologies and based on the use of two custom integrated circuits (ICs). As far as the nanopores interface system is concerned, an automatic setup has been developed for the concurrent formation of bilayer lipid membranes combined with a custom parallel readout electronic system creating a complete portable platform for nanopores or ion channels studies. On the other hand, referring to the nanowire readout hybrid interface, two systems enabling to perform parallel, real-time, complex impedance measurements based on lock-in technique, as well as impedance spectroscopy measurements have been developed. This feature enable to experimentally investigate the possibility to enrich informations on the bio-nanosensors concurrently acquiring impedance magnitude and phase thus investigating capacitive contributions of bioanalytical interactions on biosensor surface.

La migrazione del chagas: Costruzione bio-medica e socio-politica delle malattie tropicali dimenticate

Questo studio propone un'esplorazione dei nessi tra processi migratori ed esperienze di salute e malattia a partire da un'indagine sulle migrazioni provenienti dall'America latina in Emilia-Romagna. Contemporaneamente indaga i termini del dibattito sulla diffusione della Malattia di Chagas, “infezione tropicale dimenticata” endemica in America centro-meridionale che, grazie all'incremento dei flussi migratori transnazionali, viene oggi riconfigurata come 'emergente' in alcuni contesti di immigrazione. Attraverso i paradigmi teorico-metodologici disciplinari dell'antropologia medica, della salute globale e degli studi sulle migrazioni, si è inteso indagare la natura della relazione tra “dimenticanza” ed “emergenza” nelle politiche che caratterizzano il contesto migratorio europeo e italiano nello specifico. Si sono analizzate questioni vincolate alla legittimità degli attori coinvolti nella ridefinizione del fenomeno in ambito pubblico; alle visioni che informano le strategie sanitarie di presa in carico dell'infezione; alle possibili ricadute di tali visioni nelle pratiche di cura. Parte della ricerca si è realizzata all'interno del reparto ospedaliero ove è stato implementato il primo servizio di diagnosi e trattamento per l'infezione in Emilia-Romagna. È stata pertanto realizzata una etnografia fuori/dentro al servizio, coinvolgendo i principali soggetti del campo di indagine -immigrati latinoamericani e operatori sanitari-, con lo scopo di cogliere visioni, logiche e pratiche a partire da un'analisi della legislazione che regola l'accesso al servizio sanitario pubblico in Italia. Attraverso la raccolta di narrazioni biografiche, lo studio ha contribuito a far luce su peculiari percorsi migratori e di vita nel contesto locale; ha permesso di riflettere sulla validità di categorie come quella di “latinoamericano” utilizzata dalla comunità scientifica in stretta correlazione con il Chagas; ha riconfigurato il senso di un approccio attento alle connotazioni culturali all'interno di un più ampio ripensamento delle forme di inclusione e di partecipazione finalizzate a dare asilo ai bisogni sanitari maggiormente percepiti e alle esperienze soggettive di malattia.

Physical land degradation and loss of soil fertility: soil structural stability and bio-physical indicators

This study investigates the changes in soil fertility due to the different aggregate breakdown mechanisms and it analyses their relationships in different soil-plant systems, using physical aggregates behavior and organic matter (OM) changes as indicators. Three case studies were investigated: i) an organic agricultural soil, where a combined method, aimed to couple aggregate stability to nutrients loss, were tested; ii) a soil biosequence, where OM chemical characterisation and fractionation of aggregates on the basis of their physical behaviour were coupled and iii) a soils sequence in different phytoclimatic conditions, where isotopic C signature of separated aggregates was analysed. In agricultural soils the proposed combined method allows to identify that the severity of aggregate breakdown affected the quantity of nutrients lost more than nutrients availability, and that P, K and Mg were the most susceptible elements to water abrasion, while C and N were mainly susceptible to wetting. In the studied Chestnut-Douglas fir biosequence, OM chemical properties affected the relative importance of OM direct and indirect mechanisms (i.e., organic and organic-metallic cements, respectively) involved in aggregate stability and nutrient losses: under Douglas fir, high presence of carboxylate groups enhanced OM-metal interactions and stabilised aggregates; whereas under Chestnut, OM directly acted and fresh, more C-rich OM was preserved. OM direct mechanism seemed to be more efficient in C preservation in aggregates. The 13C natural abundance approach showed that, according to phytoclimatic conditions, stable macroaggregates can form both around partially decomposed OM and by organic-mineral interactions. In topsoils, aggregate resistance enhanced 13C-rich OM preservation, but in subsoils C preservation was due to other mechanisms, likely OM-mineral interactions. The proposed combined approach seems to be useful in the understanding of C and nutrients fate relates to water stresses, and in future research it could provide new insights into the complexity of soil biophysical processes.

Electrochemical surface modification of Single walled carbon nanotubes and graphene-based electrodes for (bio)sensing applications

Sensors are devices that have shown widespread use, from the detection of gas molecules to the tracking of chemical signals in biological cells. Single walled carbon nanotube (SWCNT) and graphene based electrodes have demonstrated to be an excellent material for the development of electrochemical biosensors as they display remarkable electronic properties and the ability to act as individual nanoelectrodes, display an excellent low-dimensional charge carrier transport, and promote surface electrocatalysis. The present work aims at the preparation and investigation of electrochemically modified SWCNT and graphene-based electrodes for applications in the field of biosensors. We initially studied SWCNT films and focused on their topography and surface composition, electrical and optical properties. Parallel to SWCNTs, graphene films were investigated. Higher resistance values were obtained in comparison with nanotubes films. The electrochemical surface modification of both electrodes was investigated following two routes (i) the electrografting of aryl diazonium salts, and (ii) the electrophylic addition of 1, 3-benzodithiolylium tetrafluoroborate (BDYT). Both the qualitative and quantitative characteristics of the modified electrode surfaces were studied such as the degree of functionalization and their surface composition. The combination of Raman, X-ray photoelectron spectroscopy, atomic force microscopy, electrochemistry and other techniques, has demonstrated that selected precursors could be covalently anchored to the nanotubes and graphene-based electrode surfaces through novel carbon-carbon formation.