Analytical challenges in the fields of Nanobioscience and Nanobiotecnology: integrated methods for separation and characterization

Nano(bio)science and nano(bio)technology play a growing and tremendous interest both on academic and industrial aspects. They are undergoing rapid developments on many fronts such as genomics, proteomics, system biology, and medical applications. However, the lack of characterization tools for nano(bio)systems is currently considered as a major limiting factor to the final establishment of nano(bio)technologies. Flow Field-Flow Fractionation (FlFFF) is a separation technique that is definitely emerging in the bioanalytical field, and the number of applications on nano(bio)analytes such as high molar-mass proteins and protein complexes, sub-cellular units, viruses, and functionalized nanoparticles is constantly increasing. This can be ascribed to the intrinsic advantages of FlFFF for the separation of nano(bio)analytes. FlFFF is ideally suited to separate particles over a broad size range (1 nm-1 μm) according to their hydrodynamic radius (rh). The fractionation is carried out in an empty channel by a flow stream of a mobile phase of any composition. For these reasons, fractionation is developed without surface interaction of the analyte with packing or gel media, and there is no stationary phase able to induce mechanical or shear stress on nanosized analytes, which are for these reasons kept in their native state. Characterization of nano(bio)analytes is made possible after fractionation by interfacing the FlFFF system with detection techniques for morphological, optical or mass characterization. For instance, FlFFF coupling with multi-angle light scattering (MALS) detection allows for absolute molecular weight and size determination, and mass spectrometry has made FlFFF enter the field of proteomics. Potentialities of FlFFF couplings with multi-detection systems are discussed in the first section of this dissertation. The second and the third sections are dedicated to new methods that have been developed for the analysis and characterization of different samples of interest in the fields of diagnostics, pharmaceutics, and nanomedicine. The second section focuses on biological samples such as protein complexes and protein aggregates. In particular it focuses on FlFFF methods developed to give new insights into: a) chemical composition and morphological features of blood serum lipoprotein classes, b) time-dependent aggregation pattern of the amyloid protein Aβ1-42, and c) aggregation state of antibody therapeutics in their formulation buffers. The third section is dedicated to the analysis and characterization of structured nanoparticles designed for nanomedicine applications. The discussed results indicate that FlFFF with on-line MALS and fluorescence detection (FD) may become the unparallel methodology for the analysis and characterization of new, structured, fluorescent nanomaterials.

Jasmonates and abscisic acid influence fruit ripening and plant water use: practical, physiological and morphological aspects

The aim of the present thesis was to better understand the physiological role of the phytohormones jasmonates (JAs) and abscisic acid (ABA) during fruit ripening in prospect of a possible field application of JAs and ABA to improve fruit yield and quality. In particular, the effects of exogenous application of these substances at different fruit developmental stages and under different experimental conditions were evaluated. Some aspects of the water relations upon ABA treatment were also analysed. Three fruit species, peach (Prunus persica L. Batsch), golden (Actinidia chinensis) and green kiwifruit (Actinidia deliciosa), and several of their cvs, were used for the trials. Different experimental models were adopted: fruits in planta, detached fruit, detached branches with fruit, girdled branches and micropropagated plants. The work was structured into four sets of experiments as follows: (i) Pre-harvest methyl jasmonate (MJ) application was performed at S3/S4 transition under field conditions in Redhaven peach; ethylene production, ripening index, fruit quality and shelf-life were assessed showing that MJ-treated fruit were firmer and thus less ripe than controls as confirmed by the Index of Absorbance Difference (IAD), but exhibited a shorter shelf-life due to an increase in ethylene production. Moreover, the time course of the expression of ethylene-, auxin- and other ripening-related genes was determined. Ripening-related ACO1 and ACS1 transcript accumulation was inhibited though transiently by MJ, and gene expression of the ethylene receptor ETR2 and of the ethylene-related transcription factor ERF2 was also altered. The time course of the expression of several auxin-related genes was strongly affected by MJ suggesting an increase in auxin biosynthesis, altered auxin conjugation and release as well as perception and transport; the need for a correct ethylene/auxin balance during ripening was confirmed. (ii) Pre- and post-harvest ABA applications were carried out under field conditions in Flaminia and O’Henry peach and Stark Red Gold nectarine fruit; ethylene production, ripening index, fruit quality and shelf-life were assessed. Results show that pre-harvest ABA applications increase fruit size and skin color intensity. Also post-harvest ABA treatments alter ripening-related parameters; in particular, while ethylene production is impaired in ABA-treated fruit soluble solids concentration (SSC) is enhanced. Following field ABA applications stem water potential was modified since ABA-treated peach trees retain more water. (iii) Pre- and post-harvest ABA and PDJ treatments were carried out in both kiwifruit species under field conditions at different fruit developmental stages and in post-harvest. Ripening index, fruit quality, plant transpiration, photosynthesis and stomatal conductance were assessed. Pre-harvest treatments enhance SSC in the two cvs and flesh color development in golden kiwifruit. Post-harvest applications of either ABA or ABA plus PDJ lead to increased SSC. In addition, ABA reduces gas exchanges in A. deliciosa. (iv) Spray, drench and dipping ABA treatments were performed in micropropagated peach plants and in peach and nectarine detached branches; plant water use and transpiration, biomass production and fruit dehydration were determined. In both plants and branches ABA significantly reduces water use and fruit dehydration. No negative effects on biomass production were detected. The present information, mainly arising from plant growth regulator application in a field environment, where plants have to cope with multiple biotic and abiotic stresses, may implement the perspectives for the use of these substances in the control of fruit ripening.

Development and performance assessment of a Plasma Focus electron beam generator for Intra-Operative Radiation Therapy

The Plasma Focus is a device designed to generate a plasma sheet between two coaxial electrodes by means of a high voltage difference. The plasma is then driven to collapse into a “pinch”, where thermonuclear conditions prevail. During the “pinch phase” charged particles are emitted, with two main components: an ion beam peaked forward and an electron beam directed backward. The electron beam emitted backward by Plasma Focus devices is being investigated as a radiation source for medical applications, using it to produce x-rays by interaction with appropriate targets (through bremsstrahlung and characteristic emission). A dedicated Plasma Focus device, named PFMA-3 (Plasma Focus for Medical Applications number 3), has been designed, put in operation and tested by the research groups of the Universities of Bologna and Ferrara. The very high dose rate (several gray per discharge, in less than 1 µs) is a peculiarity of this device that has to be investigated, as it might modify the relative biological effectiveness (RBE). Aim of this Ph.D. project was to investigate the main physical properties of the low-energy x-ray beams produced by a Plasma Focus device and their potential medical applications to IORT treatments. It was necessary to develop the optimal geometrical configuration; to evaluate the x-rays produced and their dose deposited; to estimate the energy electron spectrum produced in the “pinch phase”; to study an optimal target for the conversion of the x-rays; to conduct simulations to study the physics involved; and in order to evaluate the radio-biological features of the beam, cell holders had to be developed for both irradiations and cell growth conditions.

Innovation and economic performance of the firms in the service sector: relevant issues and open problems

This thesis is a collection of essays related to the topic of innovation in the service sector. The choice of this structure is functional to the purpose of single out some of the relevant issues and try to tackle them, revising first the state of the literature and then proposing a way forward. Three relevant issues has been therefore selected: (i) the definition of innovation in the service sector and the connected question of measurement of innovation; (ii) the issue of productivity in services; (iii) the classification of innovative firms in the service sector. Facing the first issue, chapter II shows how the initial width of the original Schumpeterian definition of innovation has been narrowed and then passed to the service sector form the manufacturing one in a reduce technological form. Chapter III tackle the issue of productivity in services, discussing the difficulties for measuring productivity in a context where the output is often immaterial. We reconstruct the dispute on the Baumol’s cost disease argument and propose two different ways to go forward in the research on productivity in services: redefining the output along the line of a characteristic approach; and redefining the inputs, particularly analysing which kind of input it’s worth saving. Chapter IV derives an integrated taxonomy of innovative service and manufacturing firms, using data coming from the 2008 CIS survey for Italy. This taxonomy is based on the enlarged definition of “innovative firm” deriving from the Schumpeterian definition of innovation and classify firms using a cluster analysis techniques. The result is the emergence of a four cluster solution, where firms are differentiated by the breadth of the innovation activities in which they are involved. Chapter 5 reports some of the main conclusions of each singular previous chapter and the points worth of further research in the future.

NMR studies on supramolecular aggregates in solution and the solid state

The aim of this work presented here is the characterization of structure and dynamics of different types of supramolecular systems by advanced NMR spectroscopy. One of the characteristic features of NMR spectroscopy is based on its high selectivity. Thus, it is desirable to exploit this technique for studying structure and dynamics of large supramolecular systems without isotopic enrichment. The observed resonance frequencies are not only isotope specific but also influenced by local fields, in particular by the distribution of electron density around the investigated nucleus. Barbituric acid are well known for forming strongly hydrogen-bonded complexes with variety of adenine derivatives. The prototropic tautomerism of this material facilitates an adjustment to complementary bases containing a DDA(A = hydrogen bond acceptor site, D = hydrogen bond donor site) or ADA sequences, thereby yielding strongly hydrogen-bonded complexes. In this contribution solid-state structures of the enolizable chromophor "1-n-butyl-5-(4-nitrophenyl)-barbituric acid" that features adjustable hydrogen-bonding properties and the molecular assemblies with three different strength of bases (Proton sponge, adenine mimetic 2,6-diaminopyridine (DAP) and 2,6-diacetamidopyridine (DAC)) are studied. Diffusion NMR spectroscopy gives information over such interactions and has become the method of choice for measuring the diffusion coefficient, thereby reflecting the effective size and shape of a molecular species. In this work the investigation of supramolecular aggregates in solution state by means of DOSY NMR techniques are performed. The underlying principles of DOSY NMR experiment are discussed briefly and more importantly two applications demonstrating the potential of this method are focused on. Calix[n]arenes have gained a rather prominent position, both as host materials and as platforms to design specific receptors. In this respect, several different capsular contents of tetra urea calix[4]arenes (benzene, benzene-d6, 1-fluorobenzene, 1-fluorobenzene-d5, 1,4-difluorobenzene, and cobaltocenium) are studied by solid state NMR spectroscopy. In the solid state, the study of the interaction between tetra urea calix[4]arenes and guest is simplified by the fact that the guests molecule remains complexed and positioned within the cavity, thus allowing a more direct investigation of the host-guest interactions.

Design and implementation of a testbed for data distribution management

Data Distribution Management (DDM) is a core part of High Level Architecture standard, as its goal is to optimize the resources used by simulation environments to exchange data. It has to filter and match the set of information generated during a simulation, so that each federate, that is a simulation entity, only receives the information it needs. It is important that this is done quickly and to the best in order to get better performances and avoiding the transmission of irrelevant data, otherwise network resources may saturate quickly. The main topic of this thesis is the implementation of a super partes DDM testbed. It evaluates the goodness of DDM approaches, of all kinds. In fact it supports both region and grid based approaches, and it may support other different methods still unknown too. It uses three factors to rank them: execution time, memory and distance from the optimal solution. A prearranged set of instances is already available, but we also allow the creation of instances with user-provided parameters. This is how this thesis is structured. We start introducing what DDM and HLA are and what do they do in details. Then in the first chapter we describe the state of the art, providing an overview of the most well known resolution approaches and the pseudocode of the most interesting ones. The third chapter describes how the testbed we implemented is structured. In the fourth chapter we expose and compare the results we got from the execution of four approaches we have implemented. The result of the work described in this thesis can be downloaded on sourceforge using the following link: https://sourceforge.net/projects/ddmtestbed/. It is licensed under the GNU General Public License version 3.0 (GPLv3).

Integration of MFA and LCA methodologies: the anthropogenic aluminium cycle in Italy

MFA and LCA methodologies were applied to analyse the anthropogenic aluminium cycle in Italy with focus on historical evolution of stocks and flows of the metal, embodied GHG emissions, and potentials from recycling to provide key features to Italy for prioritizing industrial policy toward low-carbon technologies and materials. Historical trend series were collected from 1947 to 2009 and balanced with data from production, manufacturing and waste management of aluminium-containing products, using a ‘top-down’ approach to quantify the contemporary in-use stock of the metal, and helping to identify ‘applications where aluminium is not yet being recycled to its full potential and to identify present and future recycling flows’. The MFA results were used as a basis for the LCA aimed at evaluating the carbon footprint evolution, from primary and electrical energy, the smelting process and the transportation, embodied in the Italian aluminium. A discussion about how the main factors, according to the Kaya Identity equation, they did influence the Italian GHG emissions pattern over time, and which are the levers to mitigate it, it has been also reported. The contemporary anthropogenic reservoirs of aluminium was estimated at about 320 kg per capita, mainly embedded within the transportation and building and construction sectors. Cumulative in-use stock represents approximately 11 years of supply at current usage rates (about 20 Mt versus 1.7 Mt/year), and it would imply a potential of about 160 Mt of CO2eq emissions savings. A discussion of criticality related to aluminium waste recovery from the transportation and the containers and packaging sectors was also included in the study, providing an example for how MFA and LCA may support decision-making at sectorial or regional level. The research constitutes the first attempt of an integrated approach between MFA and LCA applied to the aluminium cycle in Italy.

Interpreting Judgements using Knowledge Representation Methods and Computational Models of Argument

The goal of the present research is to define a Semantic Web framework for precedent modelling, by using knowledge extracted from text, metadata, and rules, while maintaining a strong text-to-knowledge morphism between legal text and legal concepts, in order to fill the gap between legal document and its semantics. The framework is composed of four different models that make use of standard languages from the Semantic Web stack of technologies: a document metadata structure, modelling the main parts of a judgement, and creating a bridge between a text and its semantic annotations of legal concepts; a legal core ontology, modelling abstract legal concepts and institutions contained in a rule of law; a legal domain ontology, modelling the main legal concepts in a specific domain concerned by case-law; an argumentation system, modelling the structure of argumentation. The input to the framework includes metadata associated with judicial concepts, and an ontology library representing the structure of case-law. The research relies on the previous efforts of the community in the field of legal knowledge representation and rule interchange for applications in the legal domain, in order to apply the theory to a set of real legal documents, stressing the OWL axioms definitions as much as possible in order to enable them to provide a semantically powerful representation of the legal document and a solid ground for an argumentation system using a defeasible subset of predicate logics. It appears that some new features of OWL2 unlock useful reasoning features for legal knowledge, especially if combined with defeasible rules and argumentation schemes. The main task is thus to formalize legal concepts and argumentation patterns contained in a judgement, with the following requirement: to check, validate and reuse the discourse of a judge - and the argumentation he produces - as expressed by the judicial text.

Design and Characterization of Curved and Spherical Flexure Hinges for Planar and Spatial Compliant Mechanisms

A flexure hinge is a flexible connector that can provide a limited rotational motion between two rigid parts by means of material deformation. These connectors can be used to substitute traditional kinematic pairs (like bearing couplings) in rigid-body mechanisms. When compared to their rigid-body counterpart, flexure hinges are characterized by reduced weight, absence of backlash and friction, part-count reduction, but restricted range of motion. There are several types of flexure hinges in the literature that have been studied and characterized for different applications. In our study, we have introduced new types of flexures with curved structures i.e. circularly curved-beam flexures and spherical flexures. These flexures have been utilized for both planar applications (e.g. articulated robotic fingers) and spatial applications (e.g. spherical compliant mechanisms). We have derived closed-form compliance equations for both circularly curved-beam flexures and spherical flexures. Each element of the spatial compliance matrix is analytically computed as a function of hinge dimensions and employed material. The theoretical model is then validated by comparing analytical data with the results obtained through Finite Element Analysis. A case study is also presented for each class of flexures, concerning the potential applications in the optimal design of planar and spatial compliant mechanisms. Each case study is followed by comparing the performance of these novel flexures with the performance of commonly used geometries in terms of principle compliance factors, parasitic motions and maximum stress demands. Furthermore, we have extended our study to the design and analysis of serial and parallel compliant mechanisms, where the proposed flexures have been employed to achieve spatial motions e.g. compliant spherical joints.

Detection and molecular characterization of viruses infecting Actinidia spp.

Kiwifruit (genus Actinidia) is an important horticultural crop grown in the temperate regions. The four world’s largest producers are China, Italy, New Zealand and Chile. More than 50 species are recognized in the genus but the principal species in cultivation are A. deliciosa and A. chinensis. In Italy, as well as in many other countries, the kiwifruit crop has been considered to be relatively disease free and then no certification system for this species has been developed to regulate importation of propagation plant material in the European Union. During the last years a number of fungal and bacterial diseases have been recorded such as Botrytis cinerea and Pseudomonas syringae pv. actinidiae. Since 2003, several viruses and virus-like diseases have been identified and more recent studies demonstrated that Actinidia spp can be infected by a wide range of viral agents. In collaboration with the University of Auckland we have been detected thirteen different viral species on kiwifruit plants. During the three years of my PhD I worked on the characterization of Cucumber mosaic virus (CMV) and Pelargonium zonate spot virus (PZSV). The determination of causal agents has been based on host range, symptom expression in the test plant species and morphological properties of the virus particles using transmission electron microscopy (TEM) and using specific oligonucleotide primers in reverse transcription-polymerase chain reaction (RT-PCR). Both viruses induced several symptoms on kiwifruit plants. Moreover with new technologies such as high-throughput sequencing we detected additional viruses, a new member of the family Closteroviridae and a new member of the family Totiviridae. Taking together all results of my studies it is clear that, in order to minimize the risk of serious viral disease in kiwifruit, it is vital to use virus-free propagation material in order to prevent the spread of these viruses.

Visual-somatosensory interactions in mental representations of the body and the face

The body is represented in the brain at levels that incorporate multisensory information. This thesis focused on interactions between vision and cutaneous sensations (i.e., touch and pain). Experiment 1 revealed that there are partially dissociable pathways for visual enhancement of touch (VET) depending upon whether one sees one’s own body or the body of another person. This indicates that VET, a seeming low-level effect on spatial tactile acuity, is actually sensitive to body identity. Experiments 2-4 explored the effect of viewing one’s own body on pain perception. They demonstrated that viewing the body biases pain intensity judgments irrespective of actual stimulus intensity, and, more importantly, reduces the discriminative capacities of the nociceptive pathway encoding noxious stimulus intensity. The latter effect only occurs if the pain-inducing event itself is not visible, suggesting that viewing the body alone and viewing a stimulus event on the body have distinct effects on cutaneous sensations. Experiment 5 replicated an enhancement of visual remapping of touch (VRT) when viewing fearful human faces being touched, and further demonstrated that VRT does not occur for observed touch on non-human faces, even fearful ones. This suggests that the facial expressions of non-human animals may not be simulated within the somatosensory system of the human observer in the same way that the facial expressions of other humans are. Finally, Experiment 6 examined the enfacement illusion, in which synchronous visuo-tactile inputs cause another’s face to be assimilated into the mental self-face representation. The strength of enfacement was not affected by the other’s facial expression, supporting an asymmetric relationship between processing of facial identity and facial expressions. Together, these studies indicate that multisensory representations of the body in the brain link low-level perceptual processes with the perception of emotional cues and body/face identity, and interact in complex ways depending upon contextual factors.

Study of the effect of minor compounds on the oxidative stability and physical properties of bulk oil, oil-in-water emulsion, and food emulsions

Minor components are of particular interest due to their antioxidant and biological properties. Various classes of lipophilic minor components (plant sterols (PS) and α-tocopherol) were selected as they are widely used in the food industry. A Fast GC-MS method for PS analysis in functional dairy products was set up. The analytical performance and significant reduction of the analysis time and consumables, demonstrated that Fast GC-MS could be suitable for the PS analysis in functional dairy products. Due to their chemical structure, PS can undergo oxidation, which could be greatly impacted by matrix nature/composition and thermal treatments. The oxidative stability of PS during microwave heating was evaluated. Two different model systems (PS alone and in combination) were heated up to 30 min at 1000 W. PS degraded faster when they were alone than in presence of TAG. The extent of PS degradation depends on both heating time and the surrounding medium, which can impact the quality and safety of the food product destined to microwave heating/cooking. Many minor lipid components are included in emulsion systems and can affect the rate of lipid oxidation. The oxidative stability of oil-in-water (O/W) emulsions containing PS esters, ω-3 FA and phenolic compounds, were evaluated after a 14-day storage at room temperature. Due to their surface active character, PS could be particularly prone to oxidation when they are incorporated in emulsions, as they are more exposed to water-soluble prooxidants. Finally, some minor lipophilic components may increase oxidative stability of food systems due to their antioxidant activity. á-tocopherol partitioning and antioxidant activity was determined in the presence of excess SDS in stripped soybean O/W emulsions. Results showed that surfactant micelles could play a key role as an antioxidant carrier, by potentially increasing the accessibility of hydrophobic antioxidant to the interface.

Oswald Mathias Ungers: Belvederestraße 60. Zu einer neuen Archtektur.

La presente Tesi di Dottorato intende affrontare una lettura critica della Casa in Belvederestraße 60, realizzata dall’architetto Oswald Mathias Ungers (Kaisersesch, 12 luglio 1926 – Köln, 30 settembre 2007), nel 1958-’59 a Köln-Müngersdorf, come studio per sé ed abitazione per la propria famiglia. Questo primo oggetto della ricerca viene considerato evidente espressione delle convinzioni formali e compositive dell’architetto, negli anni Cinquanta e Sessanta. A differenza di altri progetti residenziali coevi ed antecedenti, frutto di un’elaborazione autonoma, la prima casa che costruisce per sé riflette una maggiore libertà di pensiero, dettata dalla coincidenza delle figure di progettista e committente; a ciò si aggiunge anche una precisa volontà dichiarativa ed ideologica. Proprio quest’ultimo aspetto permette di introdurre il secondo oggetto della Tesi: il manifesto “ideologico”, Zu einer neuen Architektur, scritto dallo stesso Oswald Mathias Ungers e da Reinhard Gieselmann, alla fine del 1960; un breve testo che espone, con toni perentori ed inappellabili, il punto di vista dei due architetti nei confronti di un panorama architettonico e critico, caratterizzato da una sterilità di pensiero dilagante, a causa dell’egemonia costruttiva funzionalista. La ricerca indaga quindi le forti reciprocità delle due opere: casa e testo, viste in chiave di “manifesto scritto e manifesto costruito”. Il primo legame tra i due soggetti è senza dubbio la concomitanza temporale, (tra il 1958 ed il 1960) associata ad un rapporto causa-effetto, tale per cui il manifesto viene redatto a difesa delle aspre critiche scaturite dalla pubblicazione della casa sulla rivista Bauwelt. Il secondo nesso è la possibilità di comprendere le accezioni effettive dei termini impiegati nella redazione del testo, attraverso le forme di una delle opere maggiormente personali dell’architetto, estraendone il senso e conferendogli un’immagine architettonica. Si vuole creare così un rapporto biunivoco di traducibilità, dell’architettura nello scritto e della semantica ungersiana in azioni compositive.

Entwicklung eines Pikoliter-Tropfengenerators für die Massenspektrometrische Spuren- und Speziesanalytik

Die Dissertationsschrift beschäftigt sich mit der Entwicklung und Anwendung einer alternativen Probenzuführungstechnik für flüssige Proben in der Massenspektrometrie. Obwohl bereits einige Anstrengungen zur Verbesserung unternommen wurden, weisen konventionelle pneumatische Zerstäuber- und Sprühkammersysteme, die in der Elementspurenanalytik mittels induktiv gekoppeltem Plasma (ICP) standardmäßig verwendet werden, eine geringe Gesamteffizienz auf. Pneumatisch erzeugtes Aerosol ist durch eine breite Tropfengrößenverteilung gekennzeichnet, was den Einsatz einer Sprühkammer bedingt, um die Aerosolcharakteristik an die Betriebsbedingungen des ICPs anzupassen.. Die Erzeugung von Tropfen mit einer sehr engen Tropfengrößenverteilung oder sogar monodispersen Tropfen könnte die Effizienz des Probeneintrags verbessern. Ein Ziel dieser Arbeit ist daher, Tropfen, die mittels des thermischen Tintenstrahldruckverfahrens erzeugt werden, zum Probeneintrag in der Elementmassenspektrometrie einzusetzen. Das thermische Tintenstrahldruckverfahren konnte in der analytischen Chemie im Bereich der Oberflächenanalytik mittels TXRF oder Laserablation bisher zur gezielten, reproduzierbaren Deposition von Tropfen auf Oberflächen eingesetzt werden. Um eine kontinuierliche Tropfenerzeugung zu ermöglichen, wurde ein elektronischer Mikrokontroller entwickelt, der eine Dosiereinheit unabhängig von der Hard- und Software des Druckers steuern kann. Dabei sind alle zur Tropfenerzeugung relevanten Parameter (Frequenz, Heizpulsenergie) unabhängig voneinander einstellbar. Die Dosiereinheit, der "drop-on-demand" Aerosolgenerator (DOD), wurde auf eine Aerosoltransportkammer montiert, welche die erzeugten Tropfen in die Ionisationsquelle befördert. Im Bereich der anorganischen Spurenanalytik konnten durch die Kombination des DOD mit einem automatischen Probengeber 53 Elemente untersucht und die erzielbare Empfindlichkeiten sowie exemplarisch für 15 Elemente die Nachweisgrenzen und die Untergrundäquivalentkonzentrationen ermittelt werden. Damit die Vorteile komfortabel genutzt werden können, wurde eine Kopplung des DOD-Systems mit der miniaturisierten Fließinjektionsanalyse (FIA) sowie miniaturisierten Trenntechniken wie der µHPLC entwickelt. Die Fließinjektionsmethode wurde mit einem zertifizierten Referenzmaterial validiert, wobei für Vanadium und Cadmium die zertifizierten Werte gut reproduziert werden konnten. Transiente Signale konnten bei der Kopplung des Dosiersystems in Verbindung mit der ICP-MS an eine µHPLC abgebildet werden. Die Modifikation der Dosiereinheit zum Ankoppeln an einen kontinuierlichen Probenfluss bedarf noch einer weiteren Reduzierung des verbleibenden Totvolumens. Dazu ist die Unabhängigkeit von den bisher verwendeten, kommerziell erhältlichen Druckerpatronen anzustreben, indem die Dosiereinheit selbst gefertigt wird. Die Vielseitigkeit des Dosiersystems wurde mit der Kopplung an eine kürzlich neu entwickelte Atmosphärendruck-Ionisationsmethode, die "flowing atmospheric-pressure afterglow" Desorptions/Ionisations Ionenquelle (FAPA), aufgezeigt. Ein direkter Eintrag von flüssigen Proben in diese Quelle war bislang nicht möglich, es konnte lediglich eine Desorption von eingetrockneten Rückständen oder direkt von der Flüssigkeitsoberfläche erfolgen. Die Präzision der Analyse ist dabei durch die variable Probenposition eingeschränkt. Mit dem Einsatz des DOD-Systems können flüssige Proben nun direkt in die FAPA eingetragen, was ebenfalls das Kalibrieren bei quantitativen Analysen organischer Verbindungen ermöglicht. Neben illegalen Drogen und deren Metaboliten konnten auch frei verkäufliche Medikamente und ein Sprengstoffanalogon in entsprechend präpariertem reinem Lösungsmittel nachgewiesen werden. Ebenso gelang dies in Urinproben, die mit Drogen und Drogenmetaboliten versetzt wurden. Dabei ist hervorzuheben, dass keinerlei Probenvorbereitung notwendig war und zur Ermittlung der NWG der einzelnen Spezies keine interne oder isotopenmarkierte Standards verwendet wurden. Dennoch sind die ermittelten NWG deutlich niedriger, als die mit der bisherigen Prozedur zur Analyse flüssiger Proben erreichbaren. Um im Vergleich zu der bisher verwendeten "pin-to-plate" Geometrie der FAPA die Lösungsmittelverdampfung zu beschleunigen, wurde eine alternative Elektrodenanordnung entwickelt, bei der die Probe länger in Kontakt mit der "afterglow"-Zone steht. Diese Glimmentladungsquelle ist ringförmig und erlaubt einen Probeneintrag mittels eines zentralen Gasflusses. Wegen der ringförmigen Entladung wird der Name "halo-FAPA" (h-FAPA) für diese Entladungsgeometrie verwendet. Eine grundlegende physikalische und spektroskopische Charakterisierung zeigte, dass es sich tatsächlich um eine FAPA Desorptions/Ionisationsquelle handelt.

Potential vorticity and moisture in extratropical cyclones : climatology and sensitivity experiments

The development of extratropical cyclones can be seen as an interplay of three positive potential vorticity (PV) anomalies: an upper-level stratospheric intrusion, low-tropospheric diabatically produced PV, and a warm anomaly at the surface acting as a surrogate PV anomaly. In the mature stage they become vertically aligned and form a “PV tower” associated with strong cyclonic circulation. This paradigm of extratropical cyclone development provides the basis of this thesis, which will use a climatological dataset and numerical model experiments to investigate the amplitude of the three anomalies and the processes leading in particular to the formation of the diabatically produced low-tropospheric PV anomaly.rnrnThe first part of this study, based on the interim ECMWF Re-Analysis (ERA-Interim) dataset, quantifies the amplitude of the three PV anomalies in mature extratropical cyclones in different regions in the Northern Hemisphere on a climatological basis. A tracking algorithm is applied to sea level pressure (SLP) fields to identify cyclone tracks. Surface potential temperature anomalies ∆θ and vertical profiles of PV anomalies ∆PV are calculated at the time of the cyclones’ minimum SLP and during the intensification phase 24 hours before in a vertical cylinder with a radius of 200 km around the surface cyclone center. To compare the characteristics of the cyclones, they are grouped according to their location (8 regions) and intensity, where the central SLP is used as a measure of intensity. Composites of ∆PV profiles and ∆θ are calculated for each region and intensity class at the time of minimum SLP and during the cyclone intensification phase.rnrnDuring the cyclones’ development stage the amplitudes of all three anomalies increase on average. In the mature stage all three anomalies are typically larger for intense than for weak winter cyclones [e.g., 0.6 versus 0.2 potential vorticity units (PVU) at lower levels, and 1.5 versus 0.5 PVU at upper levels].rnThe regional variability of the cyclones’ vertical structure and the profile evolution is prominent (cyclones in some regions are more sensitive to the amplitude of a particular anomaly than in other regions). Values of ∆θ and low-level ∆PV are on average larger in the western parts of the oceans than in the eastern parts. In addition, a large seasonal variability can be identified, with fewer and weaker cyclones especially in the summer, associated with higher low-tropospheric PV values, but also with a higher tropopause and much weaker surface potential temperature anomalies (compared to winter cyclones).rnrnIn the second part, we were interested in the diabatic low-level part of PV towers. Evaporative sources were identified of moisture that was involved in PV production through condensation. Lagrangian backward trajectories were calculated from the region with high PV values at low-levels in the cyclones. PV production regions were identified along these trajectories and from these regions a new set of backward trajectories was calculated and moisture uptakes were traced along them. The main contribution from surface evaporation to the specific humidity of the trajectories is collected 12-72 hours prior to therntime of PV production. The uptake region for weaker cyclones with less PV in the centre is typically more localized with reduced uptake values compared to intense cyclones. However, in a qualitative sense uptakes and other variables along single trajectories do not vary much between cyclones of different intensity in different regions.rnrnA sensitivity study with the COSMO model comprises the last part of this work. The study aims at investigating the influence of synthetic moisture modification in the cyclone environment in different stages of its development. Moisture was eliminated in three regions, which were identified as important moisture source regions for PV production. Moisture suppression affected the cyclone the most in its early phase. It led to cyclolysis shortly after its genesis. Nevertheles, a new cyclone formed on the other side of a dry box and developed relatively quickly. Also in other experiments, moisture elimination led to strong intensity reduction of the surface cyclone, limited upper-level development, and delayed or missing interaction between the two.rnrnIn summary, this thesis provides novel insight into the structure of different intensity categories of extratropical cyclones from a PV perspective, which corroborates the findings from a series of previous case studies. It reveals that all three PV anomalies are typically enhanced for more intense cyclones, with important regional differences concerning the relative amplitude of the three anomalies. The moisture source analysis is the first of this kind to study the evaporation-condensation cycle related to the intensification of extratropical cyclones. Interestingly, most of the evaporation occurs during the 3 days prior to the time of maximum cyclone intensity and typically extends over fairly large areas along the track of the cyclone. The numerical model case study complements this analysis by analyzing the impact of regionally confined moisture sources for the evolution of the cyclone.