Mediterranean-type climate in the South Aegean (Eastern Mediterranean) during the Late Miocene: Evidence from isotope and element proxies

The present-day climate in the Mediterranean region is characterized by mild, wet winters and hot, dry summers. There is contradictory evidence as to whether the present-day conditions (“Mediterranean climate”) already existed in the Late Miocene. This thesis presents seasonally-resolved isotope and element proxy data obtained from Late Miocene reef corals from Crete (Southern Aegean, Eastern Mediterranean) in order to illustrate climate conditions in the Mediterranean region during this time. There was a transition from greenhouse to icehouse conditions without a Greenland ice sheet during the Late Miocene. Since the Greenland ice sheet is predicted to melt fully within the next millennia, Late Miocene climate mechanisms can be considered as useful analogues in evaluating models of Northern Hemispheric climate conditions in the future. So far, high resolution chemical proxy data on Late Miocene environments are limited. In order to enlarge the proxy database for this time span, coral genus Tarbellastraea was evaluated as a new proxy archive, and proved reliable based on consistent oxygen isotope records of Tarbellastraea and the established paleoenvironmental archive of coral genus Porites. In combination with lithostratigraphic data, global 87Sr/86Sr seawater chronostratigraphy was used to constrain the numerical age of the coral sites, assuming the Mediterranean Sea to be equilibrated with global open ocean water. 87Sr/86Sr ratios of Tarbellastraea and Porites from eight stratigraphically different sampling sites were measured by thermal ionization mass spectrometry. The ratios range from 0.708900 to 0.708958 corresponding to ages of 10 to 7 Ma (Tortonian to Early Messinian). Spectral analyses of multi-decadal time-series yield interannual δ18O variability with periods of ~2 and ~5 years, similar to that of modern records, indicating that pressure field systems comparable to those controlling the seasonality of present-day Mediterranean climate existed, at least intermittently, already during the Late Miocene. In addition to sea surface temperature (SST), δ18O composition of coral aragonite is controlled by other parameters such as local seawater composition which as a result of precipitation and evaporation, influences sea surface salinity (SSS). The Sr/Ca ratio is considered to be independent of salinity, and was used, therefore, as an additional proxy to estimate seasonality in SST. Major and trace element concentrations in coral aragonite determined by laser ablation inductively coupled plasma mass spectrometry yield significant variations along a transect perpendicular to coral growth increments, and record varying environmental conditions. The comparison between the average SST seasonality of 7°C and 9°C, derived from average annual δ18O (1.1‰) and Sr/Ca (0.579 mmol/mol) amplitudes, respectively, indicates that the δ18O-derived SST seasonality is biased by seawater composition, reducing the δ18O amplitude by 0.3‰. This value is equivalent to a seasonal SSS variation of 1‰, as observed under present-day Aegean Sea conditions. Concentration patterns of non-lattice bound major and trace elements, related to trapped particles within the coral skeleton, reflect seasonal input of suspended load into the reef environment. δ18O, Sr/Ca and non-lattice bound element proxy records, as well as geochemical compositions of the trapped particles, provide evidence for intense precipitation in the Eastern Mediterranean during winters. Winter rain caused freshwater discharge and transport of weathering products from the hinterland into the reef environment. There is a trend in coral δ18O data to more positive mean δ18O values (–2.7‰ to –1.7‰) coupled with decreased seasonal δ18O amplitudes (1.1‰ to 0.7‰) from 10 to 7 Ma. This relationship is most easily explained in terms of more positive summer δ18O. Since coral diversity and annual growth rates indicate more or less constant average SST for the Mediterranean from the Tortonian to the Early Messinian, more positive mean and summer δ18O indicate increasing aridity during the Late Miocene, and more pronounced during summers. The analytical results implicate that winter rainfall and summer drought, the main characteristics of the present-day Mediterranean climate, were already present in the Mediterranean region during the Late Miocene. Some models have argued that the Mediterranean climate did not exist in this region prior to the Pliocene. However, the data presented here show that conditions comparable to those of the present-day existed either intermittently or permanently since at least about 10 Ma.

Determinazione non invasiva della sodiemia plasmatica tramite il biosensore diascan

L’analisi presentata è stata ottenuta a partire dai dati acquisiti durante uno studio clinico presso il reparto di emodialisi dell'ospedale Ceccarini di Riccione. L’obiettivo principale dello studio clinico è quello di misurare la correlazione tra la concentrazione di sodio nel plasma del paziente misurata tramite emogas analizzatore e la conducibilità plasmatica stimata dal biosensore Diascan in vari istanti temporali intradialitici e valutare la bontà della stima della sodiemia, ottenuta dalle formule di correlazione, rispetto alle effettive misure di concentrazione. La correlazione globale ottenuta risulta discreta ma inferiore rispetto a precedenti risultati pubblicati in letteratura; si ipotizza che questo scostamento possa dipendere dalla struttura del protocollo di sperimentazione.

Transform Tectonics and Non-Volcanic Oceanic Islands

Oceanic islands can be divided, according to their origin, in volcanic and tectonic. Volcanic islands are due to excess volcanism. Tectonic islands are mainly formed due to vertical tectonic motions of blocks of oceanic lithosphere along transverse ridges flanking transform faults at slow and ultraslow mid-ocean ridges. Vertical tectonic motions are due to a reorganization of the geometry of the transform plate boundary, with the transition from a transcurrent tectonics to a transtensive and/or transpressive tectonics, with the formation of the transverse ridges. Tectonic islands can be located also at the ridge–transform intersection: in this case the uplift is due by the movement of the long-lived detachment faults located along the flanks of the mid-ocean ridges. The "Vema" paleoisland (equatorial Atlantic) is at the summit of the southern transverse ridge of the Vema transform. It is now 450 m bsl and it is capped by a carbonate platform 500 m-thick, dated by 87Sr/86Sr at 10 Ma. Three tectonic paleoislands are on the summit of the transverse ridge flanking the Romanche megatrasform (equatorial Atlantic). They are now about 1,000 m bsl and they are formed by 300 m-thick carbonate platforms dated by 87Sr/86Sr, between 11 and 6 Ma. The tectonic paleoisland “Atlantis Bank" is located in the South-Western Indian Ridge, along the Atlantis II transform, and it is today 700 m bsl. The only modern example of oceanic tectonics island is the St. Paul Rocks (equatorial Atlantic), located along the St. Paul transform. This archipelago is the top of a peridotitic massif that it is now a left overstep undergoing transpression. Oceanic volcanic islands are characterized by rapid growth and subsequent thermal subsidence and drowning; in contrast, oceanic tectonic islands may have one or more stages of emersion related to vertical tectonic events along the large oceanic fracture zones.

Grundlegende Untersuchungen zum Verhalten ausgewählter Seltenerdelemente bei Explosionen und zur Anwendbarkeit spezieller Methoden zu deren Analyse

Bisher ist bei forensischen Untersuchungen von Explosionen die Rückverfolgung der verwendeten Sprengstoffe begrenzt, da das Material in aller Regel bei der Explosion zerstört wird. Die Rückverfolgung von Sprengstoffen soll mit Hilfe von Identifikations-Markierungssubstanzen erleichtert werden. Diese stellen einen einzigartigen Code dar, der auch nach einer Sprengung wiedergefunden und identifiziert werden kann. Die dem Code zugeordneten, eindeutigen Informationen können somit ausgelesen werden und liefern der Polizei bei der Aufklärung weitere Ansätze.rnZiel der vorliegenden Arbeit ist es, das Verhalten von ausgewählten Seltenerdelementen (SEE) bei Explosion zu untersuchen. Ein auf Lanthanoidphosphaten basierender Identifikations-Markierungsstoff bietet die Möglichkeit, verschiedene Lanthanoide innerhalb eines einzelnen Partikels zu kombinieren, wodurch eine Vielzahl von Codes generiert werden kann. Somit kann eine Veränderung der Ausgangszusammensetzung des Codes auch nach einer Explosion durch die Analyse eines einzelnen Partikels sehr gut nachvollzogen und somit die Eignung des Markierungsstoffes untersucht werden. Eine weitere Zielsetzung ist die Überprüfung der Anwendbarkeit der Massenspektrometrie mit induktiv gekoppeltem Plasma (ICP-MS) und Partikelanalyse mittels Rasterelektronenmikroskopie (REM) für die Analyse der versprengten Identifikations-Markierungssubstanzen. rnDie Ergebnisbetrachtungen der ICP-MS-Analyse und REM-Partikelanalyse deuten zusammenfassend auf eine Fraktionierung der untersuchten Lanthanoide oder deren Umsetzungsprodukte nach Explosion in Abhängigkeit ihrer thermischen Belastbarkeit. Die Befunde zeigen eine Anreicherung der Lanthanoide mit höherer Temperaturbeständigkeit in größeren Partikeln, was eine Anreicherung von Lanthanoiden mit niedrigerer Temperaturbeständigkeit in kleineren Partikeln impliziert. Dies lässt sich in Ansätzen durch einen Fraktionierungsprozess in Abhängigkeit der Temperaturstabilität der Lanthanoide oder deren Umsetzungsprodukten erklären. Die der Fraktionierung zugrunde liegenden Mechanismen und deren gegenseitige Beeinflussung bei einer Explosion konnten im Rahmen dieser Arbeit nicht abschließend geklärt werden.rnDie generelle Anwendbarkeit und unter Umständen notwendige, komplementäre Verwendung der zwei Methoden ICP-MS und REM-Partikelanalyse wird in dieser Arbeit gezeigt. Die ICP-MS stellt mit großer untersuchter Probenfläche und hoher Genauigkeit eine gute Methode zur Charakterisierung der Konzentrationsverhältnisse der untersuchten Lanthanoide dar. Die REM-Partikelanalyse hingegen ermöglicht im Falle von Kontamination der Proben mit anderen Lanthanoid-haltigen Partikeln eine eindeutige Differenzierung der Elementvergesellschaftung pro Partikel. Sie kann somit im Gegensatz zur ICP-MS Aufschluss über die Art und Zusammensetzung der Kontamination geben. rnInnerhalb der vorgenommenen Untersuchungen stellte die bei der ICP-MS angewandte Probennahmetechnik eine ideale Art der Probennahme dar. Bei anderen Oberflächen könnte diese jedoch in Folge der in verschiedenen Partikelgrößen resultierenden Fraktionierung zu systematisch verfälschten Ergebnissen führen. Um die generelle Anwendbarkeit der ICP-MS im Hinblick auf die Analyse versprengter Lanthanoide zu gewährleisten, sollte eine Durchführung weiterer Sprengungen auf unterschiedlichen Probenoberflächen erfolgen und gegebenenfalls weitere Probennahme-, Aufschluss- und Anreicherungsverfahren evaluiert werden.rn

Boron determination in biological samples - Intercomparison of three analytical methods to assist development of a treatment protocol for neoplastic diseases of the liver with Boron Neutron Capture Therapy

Die Bor-Neuroneneinfang-Therapie (engl.: Boron Neutron Capture Therapy, BNCT) ist eine indirekte Strahlentherapie, welche durch die gezielte Freisetzung von dicht ionisierender Strahlung Tumorzellen zerstört. Die freigesetzten Ionen sind Spaltfragmente einer Kernreaktion, bei welcher das Isotop 10B ein niederenergetisches (thermisches) Neutron einfängt. Das 10B wird durch ein spezielles Borpräparat in den Tumorzellen angereichert, welches selbst nicht radioaktiv ist. rnAn der Johannes Gutenberg-Universität Mainz wurde die Forschung für die Anwendung eines klinischen Behandlungsprotokolls durch zwei Heilversuche bei Patienten mit kolorektalen Lebermetastasen an der Universität Pavia, Italien, angeregt, bei denen die Leber außerhalb des Körpers in einem Forschungsreaktor bestrahlt wurde. Als erster Schritt wurde in Kooperation verschiedener universitärer Institute eine klinische Studie zur Bestimmung klinisch relevanter Parameter wie der Borverteilung in verschiedenen Geweben und dem pharmakokinetischen Aufnahmeverhalten des Borpräparates initiiert.rnDie Borkonzentration in den Gewebeproben wurde hinsichtlich ihrer räumlichen Verteilung in verschiedenen Zellarealen bestimmt, um mehr über das Aufnahmeverhalten der Zellen für das BPA im Hinblick auf ihre biologischen Charakteristika zu erfahren. Die Borbestimung wurde per Quantitative Neutron Capture Radiography, Prompt Gamma Activation Analysis und Inductively Coupled Plasma Mass Spectroscopy parallel zur histologischen Analyse des Gewebes durchgeführt. Es war möglich zu zeigen, dass in Proben aus Tumorgewebe und aus tumorfreiem Gewebe mit unterschiedlichen morphologischen Eigenschaften eine sehr heterogene Borverteilung vorliegt. Die Ergebnisse der Blutproben werden für die Erstellung eines pharmakokinetischen Modells verwendet und sind in Übereinstimmung mit existierenden pharmakokinetische Modellen. Zusätzlich wurden die Methoden zur Borbestimmung über speziell hergestellte Referenzstandards untereinander verglichen. Dabei wurde eine gute Übereinstimmung der Ergebnisse festgestellt, ferner wurde für alle biologischen Proben Standardanalyseprotokolle erstellt.rnDie bisher erhaltenen Ergebnisse der klinischen Studie sind vielversprechend, lassen aber noch keine endgültigen Schlussfolgerungen hinsichtlich der Wirksamkeit von BNCT für maligne Lebererkrankungen zu. rn

Numerical and Analytical Methods for Laser-Plasma Acceleration Physics

Theories and numerical modeling are fundamental tools for understanding, optimizing and designing present and future laser-plasma accelerators (LPAs). Laser evolution and plasma wave excitation in a LPA driven by a weakly relativistically intense, short-pulse laser propagating in a preformed parabolic plasma channel, is studied analytically in 3D including the effects of pulse steepening and energy depletion. At higher laser intensities, the process of electron self-injection in the nonlinear bubble wake regime is studied by means of fully self-consistent Particle-in-Cell simulations. Considering a non-evolving laser driver propagating with a prescribed velocity, the geometrical properties of the non-evolving bubble wake are studied. For a range of parameters of interest for laser plasma acceleration, The dependence of the threshold for self-injection in the non-evolving wake on laser intensity and wake velocity is characterized. Due to the nonlinear and complex nature of the Physics involved, computationally challenging numerical simulations are required to model laser-plasma accelerators operating at relativistic laser intensities. The numerical and computational optimizations, that combined in the codes INF&RNO and INF&RNO/quasi-static give the possibility to accurately model multi-GeV laser wakefield acceleration stages with present supercomputing architectures, are discussed. The PIC code jasmine, capable of efficiently running laser-plasma simulations on Graphics Processing Units (GPUs) clusters, is presented. GPUs deliver exceptional performance to PIC codes, but the core algorithms had to be redesigned for satisfying the constraints imposed by the intrinsic parallelism of the architecture. The simulation campaigns, run with the code jasmine for modeling the recent LPA experiments with the INFN-FLAME and CNR-ILIL laser systems, are also presented.

Development and application of an analytical method for the determination of total atmospheric biogenic non-methane organic carbon

Ein wesentlicher Anteil an organischem Kohlenstoff, der in der Atmosphäre vorhanden ist, wird als leichtflüchtige organische Verbindungen gefunden. Diese werden überwiegend durch die Biosphäre freigesetzt. Solche biogenen Emissionen haben einen großen Einfluss auf die chemischen und physikalischen Eigenschaften der Atmosphäre, indem sie zur Bildung von bodennahem Ozon und sekundären organischen Aerosolen beitragen. Um die Bildung von bodennahem Ozon und von sekundären organischen Aerosolen besser zu verstehen, ist die technische Fähigkeit zur genauen Messung der Summe dieser flüchtigen organischen Substanzen notwendig. Häufig verwendete Methoden sind nur auf den Nachweis von spezifischen Nicht-Methan-Kohlenwasserstoffverbindungen fokussiert. Die Summe dieser Einzelverbindungen könnte gegebenenfalls aber nur eine Untergrenze an atmosphärischen organischen Kohlenstoffkonzentrationen darstellen, da die verfügbaren Methoden nicht in der Lage sind, alle organischen Verbindungen in der Atmosphäre zu analysieren. Einige Studien sind bekannt, die sich mit der Gesamtkohlenstoffbestimmung von Nicht-Methan-Kohlenwasserstoffverbindung in Luft beschäftigt haben, aber Messungen des gesamten organischen Nicht-Methan-Verbindungsaustauschs zwischen Vegetation und Atmosphäre fehlen. Daher untersuchten wir die Gesamtkohlenstoffbestimmung organische Nicht-Methan-Verbindungen aus biogenen Quellen. Die Bestimmung des organischen Gesamtkohlenstoffs wurde durch Sammeln und Anreichern dieser Verbindungen auf einem festen Adsorptionsmaterial realisiert. Dieser erste Schritt war notwendig, um die stabilen Gase CO, CO2 und CH4 von der organischen Kohlenstofffraktion zu trennen. Die organischen Verbindungen wurden thermisch desorbiert und zu CO2 oxidiert. Das aus der Oxidation entstandene CO2 wurde auf einer weiteren Anreicherungseinheit gesammelt und durch thermische Desorption und anschließende Detektion mit einem Infrarot-Gasanalysator analysiert. Als große Schwierigkeiten identifizierten wir (i) die Abtrennung von CO2 aus der Umgebungsluft von der organischen Kohlenstoffverbindungsfaktion während der Anreicherung sowie (ii) die Widerfindungsraten der verschiedenen Nicht-Methan-Kohlenwasserstoff-verbindungen vom Adsorptionsmaterial, (iii) die Wahl des Katalysators sowie (iiii) auftretende Interferenzen am Detektor des Gesamtkohlenstoffanalysators. Die Wahl eines Pt-Rd Drahts als Katalysator führte zu einem bedeutenden Fortschritt in Bezug auf die korrekte Ermittlung des CO2-Hintergrund-Signals. Dies war notwendig, da CO2 auch in geringen Mengen auf der Adsorptionseinheit während der Anreicherung der leichtflüchtigen organischen Substanzen gesammelt wurde. Katalytische Materialien mit hohen Oberflächen stellten sich als unbrauchbar für diese Anwendung heraus, weil trotz hoher Temperaturen eine CO2-Aufnahme und eine spätere Abgabe durch das Katalysatormaterial beobachtet werden konnte. Die Methode wurde mit verschiedenen leichtflüchtigen organischen Einzelsubstanzen sowie in zwei Pflanzenkammer-Experimenten mit einer Auswahl an VOC-Spezies getestet, die von unterschiedlichen Pflanzen emittiert wurden. Die Pflanzenkammer-messungen wurden durch GC-MS und PTR-MS Messungen begleitet. Außerdem wurden Kalibrationstests mit verschiedenen Einzelsubstanzen aus Permeations-/Diffusionsquellen durchgeführt. Der Gesamtkohlenstoffanalysator konnte den tageszeitlichen Verlauf der Pflanzenemissionen bestätigen. Allerdings konnten Abweichungen für die Mischungsverhältnisse des organischen Gesamtkohlenstoffs von bis zu 50% im Vergleich zu den begleitenden Standardmethoden beobachtet werden.

Chiral properties of two-flavour QCD at zero and non-zero temperature

Lattice Quantum Chromodynamics (LQCD) is the preferred tool for obtaining non-perturbative results from QCD in the low-energy regime. It has by nowrnentered the era in which high precision calculations for a number of phenomenologically relevant observables at the physical point, with dynamical quark degrees of freedom and controlled systematics, become feasible. Despite these successes there are still quantities where control of systematic effects is insufficient. The subject of this thesis is the exploration of the potential of todays state-of-the-art simulation algorithms for non-perturbativelyrn$\mathcal{O}(a)$-improved Wilson fermions to produce reliable results in thernchiral regime and at the physical point both for zero and non-zero temperature. Important in this context is the control over the chiral extrapolation. Thisrnthesis is concerned with two particular topics, namely the computation of hadronic form factors at zero temperature, and the properties of the phaserntransition in the chiral limit of two-flavour QCD.rnrnThe electromagnetic iso-vector form factor of the pion provides a platform to study systematic effects and the chiral extrapolation for observables connected to the structure of mesons (and baryons). Mesonic form factors are computationally simpler than their baryonic counterparts but share most of the systematic effects. This thesis contains a comprehensive study of the form factor in the regime of low momentum transfer $q^2$, where the form factor is connected to the charge radius of the pion. A particular emphasis is on the region very close to $q^2=0$ which has not been explored so far, neither in experiment nor in LQCD. The results for the form factor close the gap between the smallest spacelike $q^2$-value available so far and $q^2=0$, and reach an unprecedented accuracy at full control over the main systematic effects. This enables the model-independent extraction of the pion charge radius. The results for the form factor and the charge radius are used to test chiral perturbation theory ($\chi$PT) and are thereby extrapolated to the physical point and the continuum. The final result in units of the hadronic radius $r_0$ is rn$$ \left\langle r_\pi^2 \right\rangle^{\rm phys}/r_0^2 = 1.87 \: \left(^{+12}_{-10}\right)\left(^{+\:4}_{-15}\right) \quad \textnormal{or} \quad \left\langle r_\pi^2 \right\rangle^{\rm phys} = 0.473 \: \left(^{+30}_{-26}\right)\left(^{+10}_{-38}\right)(10) \: \textnormal{fm} \;, $$rn which agrees well with the results from other measurements in LQCD and experiment. Note, that this is the first continuum extrapolated result for the charge radius from LQCD which has been extracted from measurements of the form factor in the region of small $q^2$.rnrnThe order of the phase transition in the chiral limit of two-flavour QCD and the associated transition temperature are the last unkown features of the phase diagram at zero chemical potential. The two possible scenarios are a second order transition in the $O(4)$-universality class or a first order transition. Since direct simulations in the chiral limit are not possible the transition can only be investigated by simulating at non-zero quark mass with a subsequent chiral extrapolation, guided by the universal scaling in the vicinity of the critical point. The thesis presents the setup and first results from a study on this topic. The study provides the ideal platform to test the potential and limits of todays simulation algorithms at finite temperature. The results from a first scan at a constant zero-temperature pion mass of about 290~MeV are promising, and it appears that simulations down to physical quark masses are feasible. Of particular relevance for the order of the chiral transition is the strength of the anomalous breaking of the $U_A(1)$ symmetry at the transition point. It can be studied by looking at the degeneracies of the correlation functions in scalar and pseudoscalar channels. For the temperature scan reported in this thesis the breaking is still pronounced in the transition region and the symmetry becomes effectively restored only above $1.16\:T_C$. The thesis also provides an extensive outline of research perspectives and includes a generalisation of the standard multi-histogram method to explicitly $\beta$-dependent fermion actions.

Novel metallo-porphyrin based colourimetric amine sensors and their processing via plasma enhanced chemical vapour deposition at atmospheric pressure : synthesis, characterisation and mechanistic studies

Volatile amines are prominent indicators of food freshness, as they are produced during many microbiological food degradation processes. Monitoring and indicating the volatile amine concentration within the food package by intelligent packaging solutions might therefore be a simple yet powerful way to control food safety throughout the distribution chain.rnrnIn this context, this work aims to the formation of colourimetric amine sensing surfaces on different substrates, especially transparent PET packaging foil. The colour change of the deposited layers should ideally be discernible by the human eye to facilitate the determination by the end-user. rnrnDifferent tailored zinc(II) and chromium(III) metalloporphyrins have been used as chromophores for the colourimetric detection of volatile amines. A new concept to increase the porphyrins absorbance change upon exposure to amines is introduced. Moreover, the novel porphyrins’ processability during the deposition process is increased by their enhanced solubility in non-polar solvents.rnrnThe porphyrin chromophores have successfully been incorporated into polysiloxane matrices on different substrates via a dielectric barrier discharge enhanced chemical vapour deposition. This process allows the use of nitrogen as a cheap and abundant plasma gas, produces minor amounts of waste and by-products and can be easily introduced into (existing) roll-to-roll production lines. The formed hybrid sensing layers tightly incorporate the porphyrins and moreover form a porous structure to facilitate the amines diffusion to and interaction with the chromophores.rnrnThe work is completed with the thorough analysis of the porphyrins’ amine sensing performance in solution as well as in the hybrid coatings . To reveal the underlying interaction mechanisms, the experimental results are supported by DFT calculations. The deposited layers could be used for the detection of NEt3 concentrations below 10 ppm in the gas phase. Moreover, the coated foils have been tested in preliminary food storage experiments. rnrnThe mechanistic investigations on the interaction of amines with chromium(III) porphyrins revealed a novel pathway to the formation of chromium(IV) oxido porphyrins. This has been used for electrochemical epoxidation reactions with dioxygen as the formal terminal oxidant.rn

Studio dell'interazione tra un plasma jet nanopulsato con substrati metallici, dielettrici e liquidi

Il plasma è denominato quarto stato della materia ed è generalmente definito come un gas ionizzato costituito da elettroni e ioni. In ambito industriale i plasmi hanno trovato impiego per diversi tipi di applicazione quali il trattamento di superfici, la degradazione e lo smaltimento di rifiuti, il taglio di materiali, primi fra tutti i metalli. In particolare i plasmi atmosferici di non equilibrio, che possiedono la caratteristica di mantenere una temperatura macroscopica paragonabile a quella ambiente, sono studiati anche per applicazioni in campo biomedicale, oltre che in quello industriale. Da alcuni anni sono quindi oggetto di indagine per le caratteristiche di sterilizzazione di fluidi o solidi, per la coagulazione e il trattamento di lesioni e lacerazioni, per trattamenti su superfici quali la pelle, per il trattamento di cellule tumorali e staminali o per interfacce dispositivi biomedicali – corpo umano. Questo nuovo settore di ricerca, in grande sviluppo, viene comunemente definito Plasma & Medicine. Poiché in ambito biomedicale, un trattamento plasma può interessare diverse tipologie di substrati biologici e materiali, è stato scelto come obiettivo della tesi la caratterizzazione di una sorgente di plasma di non equilibrio a pressione atmosferica, denominata Plasma Jet, posta ad interagire con substrati di diversa natura (metallico, dielettrico, liquido). La sorgente utilizzata è in grado di produrre un plasma freddo e biocompatibile, generando diverse specie chimiche che garantiscono effetti molto interessanti (sterilizzazione, accelerazione della coagulazione sanguigna, cura di infezioni) per un utilizzo a contatto con il corpo umano o con componenti ingegneristiche che devono venire ad interagire con esso, quali stent, cateteri, bisturi. La caratterizzazione è stata effettuata mediante l’ausilio di due tecniche diagnostiche: la Schlieren Imaging, che permette di studiare la fluidodinamica del gas, OES (Optical Emission Spettroscopy), che permette di analizzare la composizione chimica della piuma di plasma e di determinare le specie chimiche che si producono. Questo elaborato si propone quindi di fornire una breve introduzione sul mondo dei plasmi e sulle loro caratteristiche, citando alcuni dei settori in cui viene utilizzato, industriali e biomedicali, con particolare attenzione per questi ultimi. Successivamente saranno riportati i setup utilizzati per le acquisizioni e una discussione sui risultati ottenuti dalle diverse tecniche diagnostiche utilizzate sul Jet durante i trattamenti. In ultimo sono poi riportate le conclusioni in modo da presentare le caratteristiche più importanti del comportamento della sorgente.

Uso del gas plasma per l'inattivazione di listeria monocytogenes in sistema modello e vegetali

Negli ultimi anni è aumentato l’interesse dell’industria verso lo sviluppo di tecnologie alternative ai trattamenti tradizionali degli alimenti. Tra le varie tecnologie non termiche troviamo il gas plasma. Il plasma è un gas ionizzato neutro, composto da diverse particelle. I principali agenti responsabili dell’azione battericida sembrano essere le specie reattive dell’ossigeno e dell’azoto, causando danni alle cellule microbiche. Recentemente si sta studiando l’“acqua plasmata attivata”. L’obiettivo generale di questa tesi è stato quello di verificare se trattamenti al plasma di soluzioni saline (NaCl 0.9%) possano “attivarle” dotandole di attività battericida nei confronti di un ceppo di Listeria monocytogenes (ceppo 56 Ly) e di stabilire se il materiale con cui sono costruiti gli elettrodi di un generatore di plasma del tipo DBD, possa influenzare l’efficacia delle soluzioni trattate. Si sono pertanto effettuati trattamenti al plasma di soluzioni saline utilizzando elettrodi di differenti materiali: vetro, ottone, acciaio, argento; le soluzioni così ottenute sono state analizzate in termini chimici, e se ne è valutata l’azione decontaminante nei confronti di Listeria monocytogenes 56 Ly nello stesso sistema modello e, in via preliminare, in sistema reale rappresentato da carote julienne deliberatamente contaminate con L. monocytogenes. Dai risultati ottenuti si è visto che la sensibilità di L. monocytogenes 56Ly alle soluzioni acquose trattate al plasma è influenzato sia dal tipo di materiale dell’elettrodo, sia dal tempo di esposizione. L’acciaio si è rivelato il materiale più efficace. Per quanto concerne il sistema reale, il lavaggio con acqua plasmata per 60 minuti ha determinato un livello di inattivazione di circa 1 ciclo logaritmico analogamente a quanto ottenuto con la soluzione di ipoclorito. In conclusione, i risultati ottenuti hanno evidenziato una minore efficacia dei trattamenti al plasma quando applicati ai sistemi reali, ma comunque il gas plasma ha delle buone potenzialità per la decontaminazione prodotti ortofrutticoli.

Recombinant ADAMTS13 normalizes von Willebrand factor-cleaving activity in plasma of acquired TTP patients by overriding inhibitory antibodies

Severe deficiency of the von Willebrand factor (VWF)-cleaving protease ADAMTS13 as observed in acquired thrombotic thrombocytopenic purpura (TTP) is caused by inhibitory and non-inhibitory autoantibodies directed against the protease. Current treatment with plasma exchange is considered to remove circulating antibodies and to concurrently replenish the deficient enzyme.

Detrital Zircon Evidence for Non-Laurentian Provenance, Mesoproterozoic (ca. 1490-1450 Ma) Deposition and Orogenesis in a Reconstructed Orogenic Belt, Northern New Mexico, USA: Defining the Picuris Orogeny

Detrital zircon and igneous zircon U-Pb ages are reported from Proterozoic metamorphic rocks in northern New Mexico. These data give new insight into the provenance and depositional age of a >3-km-thick metasedimentary succession and help resolve the timing of orogenesis within an area of overlapping accretionary orogens and thermal events related to the Proterozoic tectonic evolution of southwest Laurentia. Three samples from the Paleoproterozoic Vadito Group yield narrow, unimodal detrital zircon age spectra with peak ages near 1710 Ma. Igneous rocks that intrude the Vadito Group include the Cerro Alto metadacite, the Picuris Pueblo granite, and the Penasco quartz monzonite and yield crystallization ages of 1710 +/- 10 Ma, 1699 +/- 3 Ma, and 1450 +/- 10 Ma, respectively. Within the overlying Hondo Group, a metamorphosed tuff layer from the Pilar Formation yields an age of 1488 +/- 6 Ma and represents the first direct depositional age constraint on any part of the Proterozoic metasedimentary succession in northern New Mexico. Detrital zircon from the overlying Piedra Lumbre Formation yield a minimum age peak of 1475 Ma, and similar to 60 grains (similar to 25%) yield ages between 1500 Ma and 1600 Ma, possibly representing non-Laurentian detritus originating from Australia and/or Antarctica. Detrital zircons from the basal metaconglomerate and the middle quartzite member of the Marquenas Formation yield minimum age peaks of 1472 Ma and 1471 Ma, consistent with earlier results. We interpret the onset of ca. 1490-1450 Ma deposition followed by tectonic burial, regional Al2SiO5 triple-point metamorphism, and ductile deformation at depths of 12-18 km to reflect a Mesoproterozoic contractional orogenic event, possibly related to the final suturing of the Mazatzal crustal province to the southern margin of Laurentia. We propose to call this event the Picuris orogeny.

Antinociceptive efficacy and plasma concentrations of transdermal buprenorphine in dogs

To assess the antinociceptive efficacy of transdermal (TD) buprenorphine (B) in dogs, a prospective, positive-controlled experimental study was performed in 10 healthy Beagles. In an open label crossover design, the dogs initially received intravenous B (IVB, 0.02 mg kg(-1)) as a positive control, followed by TDB (52.5 mug h(-1)) 4 months later. Blood was collected at regular intervals for determination of the plasma concentrations of B ([B]) and its metabolite norbuprenorphine. The antinociceptive efficacy was assessed using thermal and mechanical models of nociception. The peak concentration [B] was 1.54 ng mL(-1) (+/-1.98) 60 h after TDB application, although three dogs had no measurable [B] after TDB. Maximum thermal threshold (TT) was 52.6 degrees C (+/-0.48) at 1h after IVB administration and 51.63 degrees C (+/-1.01) 72 h after TDB application. The significant increase in TT indicated that effective antinociception was achieved beyond 36 h after the application of TDB, lasting until patch removal. There was hysteresis between [B] and the antinociceptive effect.

Plasma leptin and mRNA expression of lipogenesis and lipolysis-related factors in bovine adipose tissue around parturition

The objective was to study changes in plasma leptin concentration parallel to changes in the gene expression of lipogenic- and lipolytic-related genes in adipose tissue of dairy cows around parturition. Subcutaneous fat biopsies were taken from 27 dairy cows in week 8 antepartum (a.p.), on day 1 postpartum (p.p.) and in week 5 p.p. Blood samples were assayed for concentrations of leptin and non-esterified fatty acids (NEFA). Subcutaneous adipose tissue was analysed for mRNA abundance by real-time qRT-PCR encoding for leptin, adiponectin receptor 1 (AdipoR1), adiponectin receptor 2 (AdipoR2), hormones-sensitive lipase (HSL), perilipin (PLIN), lipoprotein lipase (LPL), acyl-CoA synthase long-chain family member 1 (ACSL1), acetyl-CoA carboxylase (ACC), fatty acid synthase (FASN) and glycerol-3-phosphate dehydrogenase 2 (GPD2). Body weight and body condition score of the cows were lower after parturition than before parturition. The calculated energy balance was negative in week 1 and 5 p.p., with higher negative energy balance in week 1 p.p. compared with that in week 5 p.p. On day 1 p.p., highest concentrations of NEFA (353.3 mumol/l) were detected compared with the other biopsy time-points (210.6 and 107.7 mumol/l, in week 8 a.p., and week 5 p.p. respectively). Reduced plasma concentrations of leptin during p.p. when compared with a.p. would favour increasing metabolic efficiency and energy conservation for mammary function and reconstitution of body reserves. Lower mRNA abundance of ACC and FASN expression on day 1 p.p. compared with other biopsy time-points suggests an attenuation of fatty acid synthesis in subcutaneous adipose tissue shortly after parturition. Gene expression of AdipoR1, AdipoR2, HSL, PLIN, LPL, ACSL1 and GPD2 was unchanged over time.