A skin surface characterization system based on capacitive image analysis

During the last few years, several methods have been proposed in order to study and to evaluate characteristic properties of the human skin by using non-invasive approaches. Mostly, these methods cover aspects related to either dermatology, to analyze skin physiology and to evaluate the effectiveness of medical treatments in skin diseases, or dermocosmetics and cosmetic science to evaluate, for example, the effectiveness of anti-aging treatments. To these purposes a routine approach must be followed. Although very accurate and high resolution measurements can be achieved by using conventional methods, such as optical or mechanical profilometry for example, their use is quite limited primarily to the high cost of the instrumentation required, which in turn is usually cumbersome, highlighting some of the limitations for a routine based analysis. This thesis aims to investigate the feasibility of a noninvasive skin characterization system based on the analysis of capacitive images of the skin surface. The system relies on a CMOS portable capacitive device which gives 50 micron/pixel resolution capacitance map of the skin micro-relief. In order to extract characteristic features of the skin topography, image analysis techniques, such as watershed segmentation and wavelet analysis, have been used to detect the main structures of interest: wrinkles and plateau of the typical micro-relief pattern. In order to validate the method, the features extracted from a dataset of skin capacitive images acquired during dermatological examinations of a healthy group of volunteers have been compared with the age of the subjects involved, showing good correlation with the skin ageing effect. Detailed analysis of the output of the capacitive sensor compared with optical profilometry of silicone replica of the same skin area has revealed potentiality and some limitations of this technology. Also, applications to follow-up studies, as needed to objectively evaluate the effectiveness of treatments in a routine manner, are discussed.

Circoli collaterali porto-sistemici all'eco-color-Doppler addominale in pazienti con ipertensione portale cirrotica: correlazione con il gradiente porto-epatico e valore prognostico

Background. Abdominal porto-systemic collaterals (APSC) on Color-Doppler ultrasound are a frequent finding in portal hypertensive cirrhotic patients. In patients with cirrhosis, an HVPG ≥ 16mmHg has been shown to be associated with increased mortality in two studies. Non-invasive indicators of HVPG ≥ 16 mmHg might define a subgroup of high-risk patients, but data on this aspect are lacking. Aims. We aimed to investigate whether HVPG predicts mortality in patients with clinically significant portal hypertension, and if APSC may predict a severe portal hypertensive state (i.e. HVPG≥16mmHg) in patients with cirrhosis and untreated portal hypertension. Methods. We analysed paired HVPG and ultrasonographic data of 86 untreated portal hypertensive cirrhotic patients. On abdominal echo-color-Doppler data on presence, type and number of APSC were prospectively collected. HVPG was measured following published guidelines. Clinical, laboratory and endoscopic data were available in all cases. First decompensation of cirrhosis and liver-disease related mortality on follow-up (mean 28±20 months) were recorded. Results. 73% of patients had compensated cirrhosis, while 27% were decompensated. All patients had an HVPG≥10 mmHg (mean 17.8±5.1 mmHg). 58% of compensated patients and 82% of decompensated patients had an HVPG over 16 mmHg. 25% had no varices, 28% had small varices, and 47% had medium/large varices. HVPG was higher in patients with esophageal varices vs. patients without varices (19.0±4.8 vs. 14.1±4.2mmHg, p<0.0001), and correlated with Child-Pugh score (R=0.494,p=0.019). 36 (42%) patients had APSC were more frequent in decompensated patients (60% vs. 35%, p=0.03) and in patients with esophageal varices (52% vs. 9%,p=0.001). HVPG was higher in patients with APSC compared with those without PSC (19.9± 4.6 vs. 16.2± 4.9mmHg, p=0.001). The prevalence of APSC was higher in patients with HVPG≥16mmHg vs. those with HVPG<16mmHg (57% vs. 13%,p<0.0001). Decompensation was significantly more frequent in patients with HVPG≥16mmHg vs. HVPG<16mmHg (35.1% vs. 11.5%, p=0.02). On multivariate analysis only HVPG and bilirubin were independent predictors of first decompensation. 10 patients died during follow-up. All had an HVPG≥16 mmHg (26% vs. 0% in patients with HVPG <16mmHg,p=0.04). On multivariate analysis only MELD score and HVPG ≥16mmHg were independent predictors of mortality. In compensated patients the detection of APSC predicted an HVPG≥16mmHg with 92% specificity, 54% sensitivity, positive and negative likelihood ratio 7.03 and 0.50, which implies that the demonstration of APSC on ultrasound increased the probability of HVPG≥16mmHg from 58% to 91%. Conclusions. HVPG maintains an independent prognostic value in the subset of patients with cirrhosis and clinically significant portal hypertension. The presence of APSC is a specific indicator of severe portal hypertension in patients with cirrhosis. Detection of APSC on ultrasound allows the non-invasive identification of a subgroup of compensated patients with bad prognosis, avoiding the invasive measurement of HVPG.

Analyse von Biotransformationen und Naturstoffsynthesen in pflanzlichen Zellkulturen unter Anwendung der in vivo NMR-Spektroskopie ohne Markierung

Die Aufklärung von Biosynthesewegen erfolgt häufig mit Hilfe von Fütterungsexperimenten mit radioaktiven oder stabilen Isotopen markierten Präkusoren oder auf der Basis der Enzymreinigung mit anschließender molekularbiologischer Charakterisierung. Die erstgenannte Methode verlangt die Isolierung der Produkte. Jedoch besteht bei Aufarbeitung und Extraktion immer die Gefahr, daß sich der Metabolit teilweise oder vollständig chemisch verändert. Ein weiterer Nachteil der genannten Methoden ist, daß diese generell mühsam und zeitaufwendig sind. Mit Hilfe der in vivo NMR-Spektroskopie können diese Nachteile umgangen werden. In der vorliegenden Arbeit wurden Biotransformationen und Biosynthesesequenzen des Ajmalin-Biosyntheseweges mit Hilfe der in vivo NMR-Spektroskopie in Pflanzenzellkulturen von Rauvolfia serpentina und Rauvolfia serpentina x Rhazya stricta anhand der natürlichen 13C-Häufigkeit untersucht. Dafür wurden ein 700 MHz, 800 MHz und ein 500 MHz CryoProbe Spektrometer eingesetzt, um die Biotransformationen von Isatin-3-oxim und Isatin sowie die Metabolisierungen der Alkaloide Vellosimin, Vinorin, Vomilenin, Ajmalin, Nß-Methyl-dihydrochano-ajmalin und Perakin mit der 1H-13C invers korrelierten NMR-Spektroskopie zu verfolgen.

Foetal heart rate recording: analysis and comparison of different methodologies

Monitoring foetal health is a very important task in clinical practice to appropriately plan pregnancy management and delivery. In the third trimester of pregnancy, ultrasound cardiotocography is the most employed diagnostic technique: foetal heart rate and uterine contractions signals are simultaneously recorded and analysed in order to ascertain foetal health. Because ultrasound cardiotocography interpretation still lacks of complete reliability, new parameters and methods of interpretation, or alternative methodologies, are necessary to further support physicians’ decisions. To this aim, in this thesis, foetal phonocardiography and electrocardiography are considered as different techniques. Further, variability of foetal heart rate is thoroughly studied. Frequency components and their modifications can be analysed by applying a time-frequency approach, for a distinct understanding of the spectral components and their change over time related to foetal reactions to internal and external stimuli (such as uterine contractions). Such modifications of the power spectrum can be a sign of autonomic nervous system reactions and therefore represent additional, objective information about foetal reactivity and health. However, some limits of ultrasonic cardiotocography still remain, such as in long-term foetal surveillance, which is often recommendable mainly in risky pregnancies. In these cases, the fully non-invasive acoustic recording, foetal phonocardiography, through maternal abdomen, represents a valuable alternative to the ultrasonic cardiotocography. Unfortunately, the so recorded foetal heart sound signal is heavily loaded by noise, thus the determination of the foetal heart rate raises serious signal processing issues. A new algorithm for foetal heart rate estimation from foetal phonocardiographic recordings is presented in this thesis. Different filtering and enhancement techniques, to enhance the first foetal heart sounds, were applied, so that different signal processing techniques were implemented, evaluated and compared, by identifying the strategy characterized on average by the best results. In particular, phonocardiographic signals were recorded simultaneously to ultrasonic cardiotocographic signals in order to compare the two foetal heart rate series (the one estimated by the developed algorithm and the other provided by cardiotocographic device). The algorithm performances were tested on phonocardiographic signals recorded on pregnant women, showing reliable foetal heart rate signals, very close to the ultrasound cardiotocographic recordings, considered as reference. The algorithm was also tested by using a foetal phonocardiographic recording simulator developed and presented in this research thesis. The target was to provide a software for simulating recordings relative to different foetal conditions and recordings situations and to use it as a test tool for comparing and assessing different foetal heart rate extraction algorithms. Since there are few studies about foetal heart sounds time characteristics and frequency content and the available literature is poor and not rigorous in this area, a data collection pilot study was also conducted with the purpose of specifically characterising both foetal and maternal heart sounds. Finally, in this thesis, the use of foetal phonocardiographic and electrocardiographic methodology and their combination, are presented in order to detect foetal heart rate and other functioning anomalies. The developed methodologies, suitable for longer-term assessment, were able to detect heart beat events correctly, such as first and second heart sounds and QRS waves. The detection of such events provides reliable measures of foetal heart rate, potentially information about measurement of the systolic time intervals and foetus circulatory impedance.

Changes in tumor stiffness for early prediction of tumor response to sorafenib: a proof-of-concept study with elastosonography in an animal model of Hepatocellular Carcinoma (HCC)

Background and aims: Sorafenib is the reference therapy for advanced Hepatocellular Carcinoma (HCC). No method exists to predict in the very early period subsequent individual response. Starting from the clinical experience in humans that subcutaneous metastases may rapidly change consistency under sorafenib and that elastosonography a new ultrasound based technique allows assessment of tissue stiffness, we investigated the role of elastonography in the very early prediction of tumor response to sorafenib in a HCC animal model. Methods: HCC (Huh7 cells) subcutaneous xenografting in mice was utilized. Mice were randomized to vehicle or treatment with sorafenib when tumor size was 5-10 mm. Elastosonography (Mylab 70XVG, Esaote, Genova, Italy) of the whole tumor mass on a sagittal plane with a 10 MHz linear transducer was performed at different time points from treatment start (day 0, +2, +4, +7 and +14) until mice were sacrified (day +14), with the operator blind to treatment. In order to overcome variability in absolute elasticity measurement when assessing changes over time, values were expressed in arbitrary units as relative stiffness of the tumor tissue in comparison to the stiffness of a standard reference stand-off pad lying on the skin over the tumor. Results: Sor-treated mice showed a smaller tumor size increase at day +14 in comparison to vehicle-treated (tumor volume increase +192.76% vs +747.56%, p=0.06). Among Sor-treated tumors, 6 mice showed a better response to treatment than the other 4 (increase in volume +177% vs +553%, p=0.011). At day +2, median tumor elasticity increased in Sor-treated group (+6.69%, range –30.17-+58.51%), while decreased in the vehicle group (-3.19%, range –53.32-+37.94%) leading to a significant difference in absolute values (p=0.034). From this time point onward, elasticity decreased in both groups, with similar speed over time, not being statistically different anymore. In Sor-treated mice all 6 best responders at day 14 showed an increase in elasticity at day +2 (ranging from +3.30% to +58.51%) in comparison to baseline, whereas 3 of the 4 poorer responders showed a decrease. Interestingly, these 3 tumours showed elasticity values higher than responder tumours at day 0. Conclusions: Elastosonography appears a promising non-invasive new technique for the early prediction of HCC tumor response to sorafenib. Indeed, we proved that responder tumours are characterized by an early increase in elasticity. The possibility to distinguish a priori between responders and non responders based on the higher elasticity of the latter needs to be validated in ad-hoc experiments as well as a confirmation of our results in humans is warranted.

Synthese, Radioiodierung und Evaluierung von neuen MGMT-Inhibitoren und ihren Glucose-Konjugaten

Eine häufige Art der Chemotherapie ist die Behandlung von Tumoren mit alkylierenden oder chloralkylierenden Zytostatika, die eine Alkylierung von Guanin in der DNA verursachen. Daraus resultieren eine Blockierung der DNA-Synthese und ein Rückgang im Tumorwachstum. Das Enzym O6-Methylguanin-DNA-methyltransferase (MGMT) ist in der Lage, solche Schäden zu reparieren. Da MGMT auch in verschiedenen Tumorarten exprimiert wird, eine Tatsache, die therapeutische Effekte verringern könnte, wird zur Zeit die Gabe von Inhibitoren der MGMT, wie O6-Benzylguanin, vor der eigentlichen Chemotherapie untersucht. Um möglicher Weise die Selektivität dieser Verbindungen für Tumor- vs. gesundem Gewebe und auch die in vivo-Eigenschaften zu verbessern, wurden glycosylierte Inhibitoren vorgeschlagen. Für eine Entwicklung neuer MGMT-Inhibitoren wäre es hilfreich, die in vivo Bioverteilung in Tier und Mensch durch eine Markierung mit geeigneten Isotopen verfolgen zu können. Im Moment existiert keine Möglichkeit, den MGMT-Status eines Tumors nicht-invasiv zu visualisieren. Diese Information kann sehr wichtig für die Planung einer Chemotherapie mit alkylierenden oder chloralkylierenden Zytostatika sein. Mit Methoden wie der Positronen-Emissions-Tomographie (PET) oder der Einzel-Photonen-Emissions-Tomographie (SPECT) ist eine nicht-invasive Quantifizierung von biochemischen Prozessen prinzipiell möglich. Hierfür wurden verschiedenen MGMT-Inhibitoren bereits mit Isotopen wie Fluor-18, Kohlenstoff-11 un Iod-131 markiert, aber sie waren aus unterschiedlichen Gründen nicht geeignet. Das Ziel dieser Arbeit war die Entwicklung von neuen O6-derivatisierten Guaninen, die über einen C8-Spacer an der N9-Position des Guanins mit einer Glucose-Einheit konjugiert werden sollten, geeigneten Markierungsvorläufern und Radioiodierungs-Methoden. Durch Wahl eines geeigneten Radioiodisotops für die Markierung des Restes an der O6-Position des Guanins kann die ex vivo-Bioverteilung dieser Verbindungen in tumortragenden Nacktmäusen (Iod-131) und die Untersuchung der in vivo-Verteilung (Iod-123) durchgeführt werden. Daher wurden O6-(5-Iodothenyl)- (ITG) und O6-(3-Iodbenzyl)guanin-Derivate (IBG) sowie ihre Glucose-Konjugate ITGG und IBGG synthetisiert. Von diesen inaktiven Standard-Verbindungen wurden die IC50-Werte zur MGMT bestimmt. Da sie alle im nM-Bereich lagen, schienen die Verbindungen für weitere Untersuchungen geeignet zu sein. Die Radiomarkierung der Inhibitoren mit Iod-131 bzw. Iod-123 wurde durch Umsetzung der Trialkyl-stannylierten Markierungsvorläufer mit der Chloramin T-Methode in mittleren (Iod-123) bis hohen (Iod-131) radiochemischen Ausbeuten und mit hohen radiochemischen Reinheiten durchgeführt. Mit den 131I-iodierten Verbindungen wurde die spezifische Bindung zur MGMT nachgewiesen, eine Eigenschaft, die essentiell für eine weitere Verwendung dieser Derivate ist. Sie wurden auch zur Bestimmung der ex vivo-Tumor- und Organverteilung in tumortragenden Nacktmäusen (MEX(+), MEX(-), Glioblastom) verwendet. In allen Fällen war die Tumoraufnahme der nicht-konjugierten Guanin-Derivate höher als die der entsprechenden Glucose-Konjugate. Das Tumor-Blut-Verhältnis, das sehr wichtig für einen potentiellen Einsatz der Verbindungen als Tracer des MGMT-Status eines Tumors ist, variierte abhängig von der Kinetik. Zu allen Zeitpunkten war die in vivo-Deiodierung der Glucose-Konjugate deutlich geringer als die von ITG oder IBG. Unter Verwendung von [131I]IBG und [131I]IBGG wurde die Biodistribution nach Inhibition der Natrium-abhängigen Glucose-Transporter, die zumindests teilweise für die Aufnahme der MGMT-Inhibitoren in Zellen verantwortlich sind, durch Phloretin untersucht. Einen Unterschied in der Tumoraufnahme zwischen den mit Phloretin behandelten und den unbehandelten Mäusen konnte nicht beobachtet werden, wahrscheinlich weil die Akkumulation im Tumor generell niedrig war. Mit den 123I-iodierten Verbindungen [123I]IBG und [123I]IBGG wurden in vivo-Scans an tumortragenden Nacktmäusen (MEX(+), MEX(-)) mit einer Kleintier-SPECT-Kamera durchgeführt. In beiden Fällen wurde eine geringe Akkumulation in den Tumoren im Vergleich zu anderen Organen beobachtet, was die ex vivo-Biodistributionsdaten bestätigte.

Study of variability and genetic structure of European populations of Myotis emarginatus and Myotis capaccinii (Chiroptera, Vespertilionidae)

The Geoffroy’s bat Myotis emarginatus is mainly present in southern, south-eastern and central Europe (Červerný, 1999) and is often recorded from northern Spain (Quetglas, 2002; Flaquer et al., 2004). It has demonstrated the species’ preference for forest. Myotis capaccinii, confined to the Mediterranean (Guille´n, 1999), is classified as ‘vulnerable’ on a global scale (Hutson, Mickleburgh & Racey, 2001). In general, the species preferred calm waters bordered by well-developed riparian vegetation and large (> 5 m) inter-bank distances (Biscardi et al. 2007). In this study we present the first results about population genetic structure of these two species of genus Myotis. We used two methods of sampling: invasive and non-invasive techniques. A total of 323 invasive samples and a total of 107 non-invasive samples were collected and analyzed. For Myotis emarginatus we have individuated for the first time a set of 7 microsatellites, which can work on this species, started from a set developed on Myotis myotis (Castella et al. 2000). We developed also a method for analysis of non-invasive samples, that given a good percentage of positive analyzed samples. The results have highlighted for the species Myotis emarginatus the presence on the European territory of two big groups, discovered by using the microsatellites tracers. On this species, 33 haplotypes of Dloop have been identified, some of them are presented only in some colonies. We identified respectively 33 haplotypes of Dloop and 10 of cytB for Myotis emarginatus and 25 of dloop and 15 of cytB for Myotis capaccinii. Myotis emarginatus’ results, both microsatellites and mtDNA, show that there is a strong genetic flow between different colonies across Europe. The results achieved on Myotis capaccinii are very interesting, in this case either for the microsatellites or the mitochondrial DNA sequences, and it has been highlighted a big difference between different colonies.

Preparation of new crystal forms via photochemical, mechanochemical and sol-gel methods

This work of thesis involves various aspects of crystal engineering. Chapter 1 focuses on crystals containing crown ether complexes. Aspects such as the possibility of preparing these materials by non-solution methods, i.e. by direct reaction of the solid components, thermal behavior and also isomorphism and interconversion between hydrates are taken into account. In chapter 2 a study is presented aimed to understanding the relationship between hydrogen bonding capability and shape of the building blocks chosen to construct crystals. The focus is on the control exerted by shape on the organization of sandwich cations such as cobalticinium, decamethylcobalticinium and bisbenzenchromium(I) and on the aggregation of monoanions all containing carboxylic and carboxylate groups, into 0-D, 1-D, 2-D and 3-D networks. Reactions conducted in multi-component molecular assemblies or co-crystals have been recognized as a way to control reactivity in the solid state. The [2+2] photodimerization of olefins is a successful demonstration of how templated solid state synthesis can efficiently synthesize unique materials with remarkable stereoselectivity and under environment-friendly conditions. A demonstration of this synthetic strategy is given in chapter 3. The combination of various types of intermolecular linkages, leading to formation of high order aggregation and crystalline materials or to a random aggregation resulting in an amorphous precipitate, may not go to completeness. In such rare cases an aggregation process intermediate between crystalline and amorphous materials is observed, resulting in the formation of a gel, i.e. a viscoelastic solid-like or liquid-like material. In chapter 4 design of new Low Molecular Weight Gelators is presented. Aspects such as the relationships between molecular structure, crystal packing and gelation properties and the application of this kind of gels as a medium for crystal growth of organic molecules, such as APIs, are also discussed.

Anwendung der geoelektrischen 3D-Tomographie für die Analyse thermisch induzierter Strömungen im Labor

Sowohl in der Natur als auch in der Industrie existieren thermisch induzierte Strömungen. Von Interesse für diese Forschungsarbeit sind dabei die Konvektionen im Erdmantel sowie in den Glasschmelzwannen. Der dort stattfindende Materialtransport resultiert aus Unterschieden in der Dichte, der Temperatur und der chemischen Konzentration innerhalb des konvektierenden Materials. Um das Verständnis für die ablaufenden Prozesse zu verbessern, werden von zahlreichen Forschergruppen numerische Modellierungen durchgeführt. Die Verifikation der dafür verwendeten Algorithmen erfolgt meist über die Analyse von Laborexperimenten. Im Vordergrund dieser Forschungsarbeit steht die Entwicklung einer Methode zur Bestimmung der dreidimensionalen Temperaturverteilung für die Untersuchung von thermisch induzierten Strömungen in einem Versuchsbecken. Eine direkte Temperaturmessung im Inneren des Versuchsmaterials bzw. der Glasschmelze beeinflusst allerdings das Strömungsverhalten. Deshalb wird die geodynamisch störungsfrei arbeitende Impedanztomographie verwendet. Die Grundlage dieser Methode bildet der erweiterte Arrhenius-Zusammenhang zwischen Temperatur und spezifischer elektrischer Leitfähigkeit. Während der Laborexperimente wird ein zähflüssiges Polyethylenglykol-Wasser-Gemisch in einem Becken von unten her erhitzt. Die auf diese Weise generierten Strömungen stellen unter Berücksichtigung der Skalierung ein Analogon sowohl zu dem Erdmantel als auch zu den Schmelzwannen dar. Über mehrere Elektroden, die an den Beckenwänden installiert sind, erfolgen die geoelektrischen Messungen. Nach der sich anschließenden dreidimensionalen Inversion der elektrischen Widerstände liegt das Modell mit der Verteilung der spezifischen elektrischen Leitfähigkeit im Inneren des Versuchsbeckens vor. Diese wird mittels der erweiterten Arrhenius-Formel in eine Temperaturverteilung umgerechnet. Zum Nachweis der Eignung dieser Methode für die nichtinvasive Bestimmung der dreidimensionalen Temperaturverteilung wurden mittels mehrerer Thermoelemente an den Beckenwänden zusätzlich direkte Temperaturmessungen durchgeführt und die Werte miteinander verglichen. Im Wesentlichen sind die Innentemperaturen gut rekonstruierbar, wobei die erreichte Messgenauigkeit von der räumlichen und zeitlichen Auflösung der Gleichstromgeoelektrik abhängt.

Landscape ecology and genetics of the wolf in Italy

This PhD Thesis includes five main parts on diverse topics. The first two parts deal with the trophic ecology of wolves in Italy consequently to a recent increase of wild ungulates abundance. Data on wolf diet across time highlighted how wild ungulates are important food resource for wolves in Italy. Increasing wolf population, increasing numbers of wild ungulates and decreasing livestock consume are mitigating wolf-man conflicts in Italy in the near future. In the third part, non-invasive genetic sampling techniques were used to obtain genotypes and genders of about 400 wolves. Thus, wolf packs were genetically reconstructed using diverse population genetic and parentage software. Combining the results on pack structure and genetic relatedness with sampling locations, home ranges of wolf packs and dispersal patterns were identified. These results, particularly important for the conservation management of wolves in Italy, illustrated detailed information that can be retrieved from genetic identification of individuals. In the fourth part, wolf locations were combined with environmental information obtained as GIS-layers. Modern species distribution models (niche models) were applied to infer potential wolf distribution and predation risk. From the resulting distribution maps, information pastures with the highest risk of depredation were derived. This is particularly relevant as it allows identifying those areas under danger of carnivore attack on livestock. Finally, in the fifth part, habitat suitability models were combined with landscape genetic analysis. On one side landscape genetic analyses on the Italian wolves provided new information on the dynamics and connectivity of the population and, on the other side, a profound analysis of the effects that habitat suitability methods had on the parameterization of landscape genetic analyses was carried out to contributed significantly to landscape genetic theory.

Ground penetrating radar early-time technique for soil electromagnetic parameters estimation

In recent years, thanks to the technological advances, electromagnetic methods for non-invasive shallow subsurface characterization have been increasingly used in many areas of environmental and geoscience applications. Among all the geophysical electromagnetic methods, the Ground Penetrating Radar (GPR) has received unprecedented attention over the last few decades due to its capability to obtain, spatially and temporally, high-resolution electromagnetic parameter information thanks to its versatility, its handling, its non-invasive nature, its high resolving power, and its fast implementation. The main focus of this thesis is to perform a dielectric site characterization in an efficient and accurate way studying in-depth a physical phenomenon behind a recent developed GPR approach, the so-called early-time technique, which infers the electrical properties of the soil in the proximity of the antennas. In particular, the early-time approach is based on the amplitude analysis of the early-time portion of the GPR waveform using a fixed-offset ground-coupled antenna configuration where the separation between the transmitting and receiving antenna is on the order of the dominant pulse-wavelength. Amplitude information can be extracted from the early-time signal through complex trace analysis, computing the instantaneous-amplitude attributes over a selected time-duration of the early-time signal. Basically, if the acquired GPR signals are considered to represent the real part of a complex trace, and the imaginary part is the quadrature component obtained by applying a Hilbert transform to the GPR trace, the amplitude envelope is the absolute value of the resulting complex trace (also known as the instantaneous-amplitude). Analysing laboratory information, numerical simulations and natural field conditions, and summarising the overall results embodied in this thesis, it is possible to suggest the early-time GPR technique as an effective method to estimate physical properties of the soil in a fast and non-invasive way.

Automatic risk evaluation in elderly patients based on Autonomic Nervous System assessment

Dysfunction of Autonomic Nervous System (ANS) is a typical feature of chronic heart failure and other cardiovascular disease. As a simple non-invasive technology, heart rate variability (HRV) analysis provides reliable information on autonomic modulation of heart rate. The aim of this thesis was to research and develop automatic methods based on ANS assessment for evaluation of risk in cardiac patients. Several features selection and machine learning algorithms have been combined to achieve the goals. Automatic assessment of disease severity in Congestive Heart Failure (CHF) patients: a completely automatic method, based on long-term HRV was proposed in order to automatically assess the severity of CHF, achieving a sensitivity rate of 93% and a specificity rate of 64% in discriminating severe versus mild patients. Automatic identification of hypertensive patients at high risk of vascular events: a completely automatic system was proposed in order to identify hypertensive patients at higher risk to develop vascular events in the 12 months following the electrocardiographic recordings, achieving a sensitivity rate of 71% and a specificity rate of 86% in identifying high-risk subjects among hypertensive patients. Automatic identification of hypertensive patients with history of fall: it was explored whether an automatic identification of fallers among hypertensive patients based on HRV was feasible. The results obtained in this thesis could have implications both in clinical practice and in clinical research. The system has been designed and developed in order to be clinically feasible. Moreover, since 5-minute ECG recording is inexpensive, easy to assess, and non-invasive, future research will focus on the clinical applicability of the system as a screening tool in non-specialized ambulatories, in order to identify high-risk patients to be shortlisted for more complex investigations.

Electrochemical imaging of living cell metabolism: investigation on Warburg effect in cancer

Cancer is one of the principal causes of death in the world; almost 8.2 million of deaths were counted in 2012. Emerging evidences indicate that most of the tumors have an increased glycolytic rate and a detriment of oxidative phosphorylation to support abnormal cell proliferation; this phenomenon is known as aerobic glycolysis or Warburg effect. This switching toward glycolysis implies that cancer tissues metabolize approximately tenfold more glucose to lactate in a given time and the amount of lactate released from cancer tissues is much greater than from normal ones. In view of these fundamental discoveries alterations of the cellular metabolism should be considered a crucial hallmark of cancer. Therefore, the investigation of the metabolic differences between normal and transformed cells is important in cancer research and it might find clinical applications. The aim of the project was to investigate the cellular metabolic alterations at single cell level, by monitoring glucose and lactate, in order to provide a better insight in cancer research. For this purpose, electrochemical techniques have been applied. Enzyme-based electrode biosensors for lactate and glucose were –ad hoc- optimized within the project and used as probes for Scanning Electrochemical Microscopy (SECM). The UME biosensor manufacturing and optimization represented a consistent part of the work and a full description of the sensor preparation protocols and of the characterization methods employed is reported. This set-up (SECM used with microbiosensor probes) enabled the non-invasive study of cellular metabolism at single cell level. The knowledge of cancer cell metabolism is required to design more efficient treatment strategies.

Sistemi "brain-to-computer" invasivi e non invasivi: Il futuro dell' "assistive technology"

Un confronto fra metodiche invasive e non invasive per interfacce brain-to-computer (BCI), al corrente stato dell'arte. Un approfondimento sulle applicazioni mediche, in particolare l'uso nelle tecnologie per l'assistenza di pazienti con malattie degenerative del sistema motorio.

Compressed sensing in digital tomosynthesis reconstruction

In this work we study a model for the breast image reconstruction in Digital Tomosynthesis, that is a non-invasive and non-destructive method for the three-dimensional visualization of the inner structures of an object, in which the data acquisition includes measuring a limited number of low-dose two-dimensional projections of an object by moving a detector and an X-ray tube around the object within a limited angular range. The problem of reconstructing 3D images from the projections provided in the Digital Tomosynthesis is an ill-posed inverse problem, that leads to a minimization problem with an object function that contains a data fitting term and a regularization term. The contribution of this thesis is to use the techniques of the compressed sensing, in particular replacing the standard least squares problem of data fitting with the problem of minimizing the 1-norm of the residuals, and using as regularization term the Total Variation (TV). We tested two different algorithms: a new alternating minimization algorithm (ADM), and a version of the more standard scaled projected gradient algorithm (SGP) that involves the 1-norm. We perform some experiments and analyse the performance of the two methods comparing relative errors, iterations number, times and the qualities of the reconstructed images. In conclusion we noticed that the use of the 1-norm and the Total Variation are valid tools in the formulation of the minimization problem for the image reconstruction resulting from Digital Tomosynthesis and the new algorithm ADM has reached a relative error comparable to a version of the classic algorithm SGP and proved best in speed and in the early appearance of the structures representing the masses.