Bioremediation of PAHs - Limitations and soultions

Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.

Expression and cellular localization of Copper transporter 2 (Ctr2) in Mus musculus

The Ctr family is an essential part of the copper homeostasis machinery and its members share sequence homology and structural and functional features. Higher eukaryotes express two members of this family Ctr1 and Ctr2. Numerous structural and functional studies are available for Ctr1, the only high affinity Cu(I) transporter thus far identified. Ctr1 holigotrimers mediate cellular copper uptake and this protein was demonstrated to be essential for embryonic development and to play a crucial role in dietary copper acquisition. Instead very little is known about Ctr2, it bears structural homology to the yeast vacuolar copper transporter, which mediates mobilization of vacuolar copper stores. Recent studies using over-expressed epitope-tagged forms of human Ctr2 suggested a function as a low affinity copper transporter that can mediate either copper uptake from the extracellular environment or mobilization of lysosomal copper stores. Using an antibody that recognizes endogenous mouse Ctr2, we studied the expression and localization of endogenous mouse Ctr2 in cell culture and in mouse models to understand its regulation and function in copper homeostasis. By immunoblot we observed a regulation of mCtr2 protein levels in a copper and Ctr1 dependent way. Our observations in cells and transgenic mice suggest that lack of Ctr1 induces a strong downregulation of Ctr2 probably by a post-translational mechanism. By indirect immunofluorescence we observed an exclusive intracellular localization in a perinuclear compartment and no co-localization with lysosomal markers. Immunofluorescence experiments in Ctr1 null cells, supported by sequence analysis, suggest that lysosomes may play a role in mCtr2 biology not as resident compartment, but as a degradation site. In appendix a LC-mass method for analysis of algal biotoxins belonging to the family of PsP (paralytic shellfish poisoning) is described.

Mobilisation von Schwermetallen im Bereich rheinhessisches Hügelland als Folge anthropogen bedingten Nitrateintrages - Folgen für den Grundwasserschutz ?

Kurzfassung Zielsetzung der vorliegenden Arbeit war eine hydrogeologische Untersuchung zur Herkunftsbestimmung der Grundwässer im Raum Alzey/Rheinhessen. Ein erster Anlaß zu weiteren Untersuchungen war durch erhöhte Schwermetallgehalte in den Rohwässern gegeben. Im Alzeyer Raum können Kluftgrundwasserleiter (Rotliegendes und z.T. verkarstetes Kalktertiär) sowie Porengrundwasserleiter (Tertiäre Meeressande und Ablagerungen des Quartärs) unterschieden werden. Aufgrund der Lösungsinhalte ergibt sich eine Typisierung in erdalkalische Hydrogenkarbonatwässer bzw. Austauschwässer, bei denen Erdalkalien durch Alkalien ersetzt wurden. Mit verschiedenen Grundwassermodellierungen konnten mögliche 'Grundwasserneubildungs-Pfade' aufgezeigt werden. Die 1996 durchgeführte Herabsetzung des Arsengrenzwertes zwang viele Versorgungsunternehmen weitere Verfahrenstechniken zur Grundwasseraufbereitung anzuwenden. Es zeigten sich erhebliche Schwierigkeiten bei der Umsetzung der EU-Wasserrahmenrichtlinie bezogen auf das lokale Untersuchungsgebiet Alzey. Schwermetallmobilisationen im Untergrund können aufgrund anthropogen eingetragener Nitrate im sonst reduzierenden Milieu ermöglicht werden. Mittels Tritium- und FCKW-Analysen konnten Alter bzw. Verweilzeiten der Wässer bestimmt werden. Zusammen mit den Werten von Deuterium und Sauerstoff-18, Schwefel-34 und Sauerstoff-18 aus dem im Wasser gelösten Sulfat und Stickstoff-15 und Sauerstoff-18 aus dem im Wasser gelösten Nitrat, konnten Aussagen über Änderungen im Aquifermilieu getroffen werden. Es zeigte sich, daß selbst bei einem völligen Stop des Düngemitteleintrages, die Schwermetallmobilisationen in Grundwässern im Bereich Rheinhessisches Hügelland innerhalb der nächsten 30 Jahre nicht abnehmen werden.

EXAFS-Untersuchungen zur Rolle von Silicium bei der Sorption von umweltrelevanten Schwermetallen (Zn, As, Pb) in Speichermineralen (FeOOH,CSH)

Bei den Sorptions- und Desorptionsmechanismen an Mineraloberflächen ist oft nicht bekannt, durch welchen Mechanismus bestimmte Spurenelemente gebunden werden (Adsorption, Ionenaustausch, Ausfällung). Heterogene Reaktionen an der Fluid/Mineral-Grenzfläche sind im Allgemeinen sehr komplex. Ein Grund dafür ist, dass mehrere Mechanismen simultan ablaufen können. Da verschiedene Reaktionstypen räumlich getrennt ablaufen, d.h. im mikroskopischen Maßstab an unterschiedlichen Reaktionsplätzen, müssen die individuellen Reaktionsmechanismen auf atomarem Maßstab untersucht werden, um die Komplexität der Gesamtreaktion zu verstehen. Mit Hilfe der EXAFS Spektroskopie wurde die Bindungsform und -art der eingelagerten Zink- und Blei-Atome in die synthetische Calciumsilikathydratphase (CSH) und des adsorptiv gebundenen Arsens an der Oberfläche der natürlichen Eisenhydroxidphase bestimmt. Hierbei spielt Silizium eine relevante Rolle für die Immobilisierung von Schwermetallen. In beiden Fällen, in denen das Silizium einerseits als Adsorbat an der Oberfläche der Eisenhydroxidphase und andererseits in die Struktur der Mischphase gebunden vorliegt, trägt es wesentlich zur Form und Art der Bindung der Schwermetalle in die neugebildete Phase bei.

Zum Transport von partikelgebundenen Schadstoffen in der ungesättigten Zone

Bei einer Risikoabschätzung bezüglich einer Gefährdung des Schutzgutes Grundwasser müssen alle relevanten Transportpfade, auf denen Schadstoffe durch die Bodenzone bis ins Grundwasser verlagert werden, identifiziert und quantifiziert werden. Die Verlagerung von Schadstoffen gebunden an mobile Partikel im Sickerwasser wird dabei oft vernachlässigt. In dieser Arbeit wurden sowohl experimentelle Untersuchungen zum Partikeltransport in der Bodenzone als auch Szenarienmodellierungen hinsichtlich der Wechselwirkung Partikel/Schadstoff durchgeführt. Die experimentellen ungesättigten Säulenversuche wurden unter naturnahen stationären und instationären hydraulischen und hydrochemischen Bedingungen durchgeführt. Dabei wurde der Einfluss der Parameter Durchmesser Bodenmatrix, Partikelgröße, Beregnungsintensität, Oberflächenspannung und Hydrochemie auf den Transport von natürlichen und synthetischen Partikeln untersucht. Des Weiteren wurden Untersuchungen zur partikelgebundenen Verlagerung von Phenanthren durchgeführt. In einer numerischen Szenarienmodellierung mit dem Modell SMART wurde untersucht, unter welchen Randbedingungen der Transport von Partikeln gleichzeitig zu signifikanten partikelgebundenen Schadstoffkonzentrationen im Grundwasser führt. Dabei wurden die Parameter Lithologie Partikel/Boden, Hydrophobizität Schadstoff, Partikelkonzentration, Partikeldurchmesser sowie Körnung Bodenmatrix variiert. Die Ergebnisse dieser Arbeit zeigen, dass der partikelgebundene Schadstofftransportpfad in der ungesättigten Bodenzone in verschiedenen Szenarien den Anteil mobiler Schadstoffe, die mit dem Sickerwasser ins Grundwasser gelangen, signifikant erhöht. Auf Basis der experimentellen und theoretischen Untersuchungen wurde ein zweistufiges Bewertungsschema entwickelt, das bereits im Vorfeld einer Risikoabschätzung als Entscheidungshilfe hinsichtlich der Relevanz einer Mobilisierung, eines Transports und des Rückhalts von partikelgebundenen Schadstoffen in der ungesättigten Zone dient.

Speciation of Pu(III) in the environmental system humic substances-groundwater-kaolinite

For the safety assessments of nuclear waste repositories, the possible migration of the radiotoxic waste into environment must be considered. Since plutonium is the major contribution at the radiotoxicity of spent nuclear waste, it requires special care with respect to its mobilization into the groundwater. Plutonium has one of the most complicated chemistry of all elements. It can coexist in 4 oxidation states parallel in one solution. In this work is shown that in the presence of humic substances it is reduced to the Pu(III) and Pu(IV). This work has the focus on the interaction of Pu(III) with natural occurring compounds (humic substances and clay minerals bzw. Kaolinite), while Pu(IV) was studied in a parallel doctoral work by Banik (in preparation). As plutonium is expected under extreme low concentrations in the environment, very sensitive methods are needed to monitor its presence and for its speciation. Resonance ionization mass spectrometry (RIMS), was used for determining the concentration of Pu in environmental samples, with a detection limit of 106- 107 atoms. For the speciation of plutonium CE-ICP-MS was routinely used to monitor the behaviour of Pu in the presence of humic substances. In order to reduce the detection limits of the speciation methods, the coupling of CE to RIMS was proposed. The first steps have shown that this can be a powerful tool for studies of pu under environmental conditions. Further, the first steps in the coupling of two parallel working detectors (DAD and ICP_MS ) to CE was performed, for the enabling a precise study of the complexation constants of plutonium with humic substances. The redox stabilization of Pu(III) was studied and it was determined that NH2OHHCl can maintain Pu(III) in the reduced form up to pH 5.5 – 6. The complexation constants of Pu(III) with Aldrich humic acid (AHA) were determined at pH 3 and 4. the logß = 6.2 – 6.8 found for these experiments was comparable with the literature. The sorption of Pu(III) onto kaolinite was studied in batch experiments and it was determine dthat the pH edge was at pH ~ 5.5. The speciation of plutonium on the surface of kaolinite was studied by EXAFS/XANES. It was determined that the sorbed species was Pu(IV). The influence of AHA on the sorption of Pu(III) onto kaolinite was also investigated. It was determined that at pH < 5 the adsorption is enhanced by the presence of AHA (25 mg/L), while at pH > 6 the adsorption is strongly impaired (depending also on the adding sequence of the components), leading to a mobilization of plutonium in solution.

Speciation of tetravalent plutonium in contact with humic substances and kaolinite under environmental conditions

Plutonium represents the major contribution to the radiotoxicity of spent nuclear fuel over storage times of up to several hundred thousand years. The speciation of plutonium in aquifer systems is important in order to assess the risks of high-level nuclear waste disposal and to acquire a deep knowledge of the mobilization and immobilization behavior of plutonium. In aqueous solutions, plutonium can coexist in four oxidation states and each one of them has different chemical and physical behavior. Tetravalent plutonium is the most abundant under natural conditions. Therefore, detailed speciation studies of tetravalent plutonium in contact with humic substances (HS) and kaolinite as a model clay mineral have been performed in this work. Plutonium is present in the environment at an ultratrace level. Therefore, speciation of Pu at the ultratrace level is mandatory. Capillary electrophoresis (CE) coupled to resonance ionization mass spectrometry (RIMS) was used as a new speciation method. CE-RIMS enables to improve the detection limit for plutonium species by 2 to 3 orders of magnitude compared to the previously developed CE-ICP-MS. For understanding the behavior of Pu(IV) in aqueous systems, redox reactions, complexation, and sorption behavior of plutonium were studied. The redox behavior of plutonium in contact with humic acid (HA) and fulvic acid (FA) was investigated. A relatively fast reduction of Pu(VI) in contact with HS was observed. It was mainly reduced to Pu(IV) and Pu(III) within a couple of weeks. The time dependence of the Pu(IV) complexation with Aldrich HA was investigated and a complex constant (logßLC) between 6.4 - 8.4 of Pu(IV) was determined by means of ultrafiltration taking into account the loading capacity (LC). The sorption of tetravalent plutonium onto kaolinite was investigated as a function of pH in batch experiments under aerobic and anaerobic conditions. The sorption edge was found at about pH = 1 and a maximum sorption at around pH = 8.5. In the presence of CO2 at pH > 8.5, the sorption of plutonium was decreased probably due to the formation of soluble carbonate complexes. For comparison, the sorption of Th(IV) onto kaolinite was also investigated and consistent results were found. The Pu(IV) sorption onto kaolinite was studied by XANES and EXAFS at pH 1, 4, 9 and the sorbed species on kaolinite surface was Pu(IV). Depending on the pH, only 1 - 10 % of the sorbed plutonium is desorbed from kaolinite and released into a fresh solution at the same pH value. Furthermore, the sorption of HS onto kaolinite was studied as a function of pH at varying concentrations of HS, as a prerequisite to understand the more complex ternary system. The sorption of HA onto kaolinite was found to be higher than that of FA. The investigation of the ternary systems (plutonium-kaolinite-humic substances) is performed as a function of pH, concentration of HS, and the sequences of adding the reactants. The presence of HS strongly influences the sorption of Pu(IV) onto kaolinite over the entire pH range. For comparison, the influence of HS on the sorption of Th(IV) onto kaolinite was also investigated and a good agreement with the results of Pu(IV) was obtained.

'Defending the rights'. An integrated model of collective action for "public water" in Italy

In many communities, supplying water for the people is a huge task and the fact that this essential service can be carried out by the private sector respecting the right to water, is a debated issue. This dissertation investigates the mechanisms through which a 'perceived rights violation' - which represents a specific form of perceived injustice which derives from the violation of absolute moral principles – can promote collective action. Indeed, literature on morality and collective action suggests that even if many people apparently sustain high moral principles (like human rights), only a minority decides to act in order to defend them. Taking advantage of the political situation in Italy, and the recent mobilization for "public water" we hypothesized that, because of its "sacred value", the perceived violation of the right to water facilitates identification with the social movement and activism. Through five studies adopting qualitative and quantitative methods, we confirmed our hypotheses demonstrating that the perceived violation of the right to water can sustain activism and it can influence vote intentions at the referendum for 'public water'. This path to collective action coexists with other 'classical' predictors of collective action, like instrumental factors (personal advantages, efficacy beliefs) and anger. The perceived rights violation can derive both from personal values (i.e. universalism) and external factors (i.e. a mobilization campaign). Furthermore, we demonstrated that it is possible to enhance the perceived violation of the right to water and anger through a specifically designed communication campaign. The final chapter summarizes the main findings and discusses the results, suggesting some innovative line of research for collective action literature.

Ortsaufgelöste Speziation von Schwermetallen in geogenen Proben mit Röntgenabsorptionsspektrometrie (my-XAS)

Die Vergesellschaftung und Bindungsform von Arsen in Düngekalk wurde durch chemische und mineralogische Analysen sowie XANES/EXAFS-Messungen untersucht. Die durch-schnittliche As-Konzentration im Düngekalk (70 mg/kg) überschreitet den Grenzwert der DüMV (40 mg/kg). Arsen ist in Mn- (Romanechit) und Fe-Dendriten (Goethit, Ferrihydrit) angereichert. Seine Oxidationsstufe ist jeweils 5+. µ-EXAFS-Untersuchungen ergaben Hin-weise auf zweizähnige und einzähnige mononukleare Durchdringungskomplexe mit Eisen-oxid. Das Mobilisierungsverhalten von Arsen wurde durch sequentielle Extraktion des Dün-gekalks und Mobilisierungsversuche mit wassergesättigtem Boden untersucht. Die Lösung erfolgte vorwiegend im dritten Extraktionsschritt gemeinsam mit kristallinen Eisenoxiden. Unter moderat anoxischen Bedingungen war im Boden keine zusätzliche Mobilisierung von Arsen aus dem Düngekalk nachweisbar. Erhöhte As-Konzentrationen und As3+-Anteile im Porenwasser traten bei niedrigem Eh unabhängig von Kalkzugabe auf. Eine Kopplung des Arsen-Grenzwerts an den Eisenoxidgehalt erscheint sinnvoll. Ein Messaufbau für Mikro-XAS Imaging wurde in Betrieb genommen. Er ermöglicht die si-multane Erfassung einer Probenfläche von 26,6×6,6 mm² wahlweise im Transmissions- oder Fluoreszenzmodus mit der räumlichen Auflösung 52×52 µm² durch eine CCD-Kamera. Zur Datenverarbeitung wurden IDL-Programme sowie die Fernerkundungssoftware ENVI ver-wendet. Die Messergebnisse zeigen weniger Störungen und Rauschen als die Ergebnisse frü-herer Messungen mit einem Prototyp. Die Ergebnisse und Erfahrungen der Messungen liefern Hinweise für die weitere erfolgreiche Nutzung des Messaufbaus.

Study of the interactions of Neptunium with humic substances and the clay mineral montmorillonite by direct and non direct speciation methods

For the safety assessment of radioactive waste, the possibility of radionuclide migration has to be considered. Since Np (and also Th due to the long-lived 232-Th) will be responsible for the greatest amount of radioactivity one million years after discharge from the reactor, its (im)-mobilization in the geosphere is of great importance. Furthermore, the chemistry of Np(V) is quite similar (but not identical) to the chemistry of Pu(V). Three species of neptunium may be found in the near field of the waste disposal, but pentavalent neptunium is the most abundant species under a wide range of natural conditions. Within this work, the interaction of Np(V) with the clay mineral montmorillonite and melanodins (as model substances for humic acids) was studied. The sorption of neptunium onto gibbsite, a model clay for montmorillonite, was also investigated. The sorption of neptunium onto γ-alumina and montmorillonite was studied in a parallel doctoral work by S. Dierking. Neptunium is only found in ultra trace amounts in the environment. Therefore, sensitive and specific methods are needed for its determination. The sorption was determined by γ spectroscopy and LSC for the whole concentration range studied. In addition the combination of these techniques with ultrafiltration allowed the study of Np(V) complexation with melanoidins. Regrettably, the available speciation methods (e.g. CE-ICP-MS and EXAFS) are not capable to detect the environmentally relevant neptunium concentrations. Therefore, a combination of batch experiments and speciation analyses was performed. Further, the preparation of hybrid clay-based materials (HCM) montmorillonitemelanoidins for sorption studies was achieved. The formation of hybrid materials begins in the interlayers of the montmorillonite, and then the organic material spreads over the surface of the mineral. The sorption of Np onto HCM was studied at the environmentally relevant concentrations and the results obtained were compared with those predicted by the linear additive model by Samadfam. The sorption of neptunium onto gibbsite was studied in batch experiments and the sorption maximum determined at pH~8.5. The sorption isotherm pointed to the presence of strong and weak sorption sites in gibbsite. The Np speciation was studied by using EXAFS, which showed that the sorbed species was Np(V). The influence of M42 type melanodins on the sorption of Np(V) onto montmorillonite was also investigated at pH 7. The sorption of the melanoidins was affected by the order in which the components were added and by ionic strength. The sorption of Np was affected by ionic strength, pointing to outer sphere sorption, whereas the presence of increasing amounts of melanoidins had little influence on Np sorption.

Studio di fase I sulla reinfusione intraepatica di cellule staminali CD 133+ altamente purificate nei pazienti con malattia epatica terminale

Numerose evidenze sperimentali hanno dimostrato il contributo delle cellule staminali di derivazione midollare nei processi di rigenerazione epatica dopo danno tissutale. E’ cresciuto pertanto l’interesse sul loro potenziale impiego in pazienti con cirrosi. Questo studio si propone di valutare la fattibilità e la sicurezza della reinfusione intraepatica di cellule staminali midollari autologhe CD133+ in 12 pazienti con insufficienza epatica terminale definita da un punteggio di Model for End Stage of Liver Disease (MELD) compreso tra 17 e 25. L’efficacia in termini di funzionalità epatica rappresenta un obiettivo secondario. Previa mobilizzazione nel sangue periferico mediante somministrazione di granulocyte-colony stimulating factor (G-CSF) alla dose di 7,5 mcg/Kg/b.i.d. e raccolta per leucoaferesi, le cellule CD133+ altamente purificate vengono reinfuse in arteria epatica a partire da 5x104/Kg fino a 1x106/kg. Nei tre giorni successivi si somministra G-CSF per favorire l’espansione e l’attecchimento delle cellule. Durante la mobilizzazione, la reinfusione e nei 12 mesi successivi i pazienti sono sottoposti a periodici controlli clinici, laboratoristici e strumentali e ad attenta valutazione di effetti collaterali. Lo studio è tuttora in corso e ad oggi, 11 pazienti sono stati sottoposti a reinfusione e 4 hanno completato i 12 mesi di follow-up. Il G-CSF è stato ben tollerato e ha consentito di ottenere una buona espansione cellulare. Dopo la reinfusione sono stati documentati un ematoma inguinale e due episodi transitori di encefalopatia portosistemica. Durante il follow-up 4 pazienti sono stati trapiantati e 2 sono morti. Non è stata osservata alcuna modificazione significativa degli indici di funzione epatica. Questi risultati preliminari confermano la possibilità di mobilizzare e reinfondere un numero adeguato di cellule staminali di derivazione midollare in pazienti con malattia epatica in stadio terminale.

Variation of stable silicon isotopes: Analytical developments and applications in Precambrian geochemistry

Die vorliegende Dissertation behandelt die Gesamtgesteinsanalyse stabiler Siliziumisotope mit Hilfe einer „Multi Collector-ICP-MS“. Die Analysen fanden in Kooperation mit dem „Royal Museum for Central Africa“ in Belgien statt. Einer der Schwerpunkte des ersten Kapitels ist die erstmalige Analyse des δ30Si –Wertes an einem konventionellen Nu PlasmaTM „Multi-Collector ICP-MS“ Instrument, durch die Eliminierung der den 30Si “peak” überlagernden 14N16O Interferenz. Die Analyse von δ30Si wurde durch technische Modifikationen der Anlage erreicht, welche eine höherer Massenauflösung ermöglichten. Die sorgsame Charakterisierung eines adäquaten Referenzmaterials ist unabdingbar für die Abschätzung der Genauigkeit einer Messung. Die Bestimmung der „U.S. Geological Survey“ Referenzmaterialien bildet den zweiten Schwerpunkt dieses Kapitales. Die Analyse zweier hawaiianischer Standards (BHVO-1 and BHVO-2), belegt die präzise und genaue δ30Si Bestimmung und bietet Vergleichsdaten als Qualitätskontrolle für andere Labore. Das zweite Kapitel befasst sich mit kombinierter Silizium-/Sauerstoffisotope zur Untersuchung der Entstehung der Silizifizierung vulkanischer Gesteine des „Barberton Greenstone Belt“, Südafrika. Im Gegensatz zu heute, war die Silizifizierung der Oberflächennahen Schichten, einschließlich der „Chert“ Bildung, weitverbreitete Prozesse am präkambrischen Ozeanboden. Diese Horizonte sind Zeugen einer extremen Siliziummobilisierung in der Frühzeit der Erde. Dieses Kapitel behandelt die Analyse von Silizium- und Sauerstoffisotopen an drei unterschiedlichen Gesteinsprofilen mit unterschiedlich stark silizifizierten Basalten und überlagernden geschichteten „Cherts“ der 3.54, 3.45 und 3.33 Mill. Jr. alten Theespruit, Kromberg und Hooggenoeg Formationen. Siliziumisotope, Sauerstoffisotope und die SiO2-Gehalte demonstrieren in allen drei Gesteinsprofilen eine positive Korrelation mit dem Silizifizierungsgrad, jedoch mit unterschiedlichen Steigungen der δ30Si-δ18O-Verhältnisse. Meerwasser wird als Quelle des Siliziums für den Silizifizierungsprozess betrachtet. Berechnungen haben gezeigt, dass eine klassische Wasser-Gestein Wechselwirkung die Siliziumisotopenvariation nicht beeinflussen kann, da die Konzentration von Si im Meerwasser zu gering ist (49 ppm). Die Daten stimmen mit einer Zwei-Endglieder-Komponentenmischung überein, mit Basalt und „Chert“ als jeweilige Endglieder. Unsere gegenwärtigen Daten an den „Cherts“ bestätigen einen Anstieg der Isotopenzusammensetzung über der Zeit. Mögliche Faktoren, die für unterschiedliche Steigungen der δ30Si-δ18O Verhältnisse verantwortlich sein könnten sind Veränderungen in der Meerwasserisotopie, der Wassertemperatur oder sekundäre Alterationseffekte. Das letzte Kapitel beinhaltet potentielle Variationen in der Quellregion archaischer Granitoide: die Si-Isotopen Perspektive. Natriumhaltige Tonalit-Trondhjemit-Granodiorit (TTG) Intrusiva repräsentieren große Anteile der archaischen Kruste. Im Gegensatz dazu ist die heutige Kruste kaliumhaltiger (GMS-Gruppe: Granit-Monzonite-Syenite). Prozesse, die zu dem Wechsel von natriumhaltiger zu kaliumhaltiger Kruste führten sind die Thematik diesen Kapitels. Siliziumisotopenmessungen wurden hier kombiniert mit Haupt- und Spurenelementanalysen an unterschiedlichen Generationen der 3.55 bis 3.10 Mill. Yr. alten TTG und GMS Intrusiva aus dem Arbeitsgebiet. Die δ30Si-Werte in den unterschiedlichen Plutonit Generationen zeigen einen leichten Anstieg der Isotopie mit der Zeit, wobei natriumhaltige Intrusiva die niedrigste Si-Isotopenzusammensetzung aufweisen. Der leichte Anstieg in der Siliziumisotopenzusammensetzung über die Zeit könnte auf unterschiedliche Temperaturbedingungen in der Quellregion der Granitoide hinweisen. Die Entstehung von Na-reichen, leichten d30Si Granitoiden würde demnach bei höheren Temperaturen erfolgen. Die Ähnlichkeit der δ30Si-Werte in archaischen K-reichen Plutoniten und phanerozoischen K-reichen Plutoniten wird ebenfalls deutlich.

Valutazione dell'efficacia dell'infusione intraepatica di cellule staminali (SC) autologhe CD133+ in pazienti affetti da cirrosi ed insufficienza epatica di grado avanzato

Numerose evidenze sperimentali hanno dimostrato il contributo delle cellule staminali (SC) di derivazione midollare nei processi di rigenerazione epatica dopo danno tissutale. E’ cresciuto pertanto l’interesse sul loro potenziale impiego in pazienti con cirrosi. Questo studio si proponeva di valutare la fattibilità e la sicurezza della reinfusione intraepatica di cellule staminali midollari autologhe CD133+ in 12 pazienti con insufficienza epatica terminale. Previa mobilizzazione nel sangue periferico mediante somministrazione di granulocyte-colony stimulating factor (G-CSF) alla dose di 7,5 mcg/Kg/b.i.d. e raccolta per leucoaferesi (solo se la concentrazione di CD133 + SC era > 8/μL), le cellule CD133+ altamente purificate sono state reinfuse in arteria epatica a partire da 5x104/Kg fino a 1x106/kg. Nei tre giorni successivi è stato somministrato G-CSF per favorire l’espansione e l’attecchimento delle cellule. Durante la fase della mobilizzazione e quella della reinfusione sono stati eseguiti saggi biologici quali: caratterizzazione fenotipica delle SC circolanti, saggi clonogenici, valutazione della concentrazione sierica del Hepatocyte Growth Factor (HGF), Stromal-Derived Factor-1 (SDF-1) ed il Vascular-Endotelial Growth Factor (VEGF) e caratterizzazione fenotipica delle CD133+SC purificate. Fino ad oggi sono stati reinfusi 12 pazienti. Questi dati preliminari suggeriscono che è possibile mobilizzare e reinfondere un numero considerevole di SC autologhe CD133+ altamente purificate in pazienti con ESLD . Gli studi biologici mostrano che: il numero di progenitori ematopoietici ed endoteliali circolanti è aumentato dopo il trattamento con G–CSF; le SCs CD133+ altamente purificato esprimono marcatori emopoietici ed endoteliali; la concentrazione sierica di HGF, SDF-1, VEGF e la capacità clonogenica di progenitori emopoietici sono aumentati durante la mobilitazione e nelle fasi di reinfusione; il potenziale clonogenico dei progenitori endoteliali mostra espressione variabile.

A SMO inhibitor drug reduces the progenitor cell's maintenance in the Drosophila hematopoietic organ: a novel model to study Chronic Myelogenous Leukemia relapse

The chronic myeloid leukemia complexity and the difficulties of disease eradication have recently led to the development of drugs which, together with the inhibitors of TK, could eliminate leukemia stem cells preventing the occurrence of relapses in patients undergoing transplantation. The Hedgehog (Hh) signaling pathway positively regulates the self-renewal and the maintenance of leukemic stem cells and not, and this function is evolutionarily conserved. Using Drosophila as a model, we studied the efficacy of the SMO inhibitor drug that inhibit the human protein Smoothened (SMO). SMO is a crucial component in the signal transduction of Hh and its blockade in mammals leads to a reduction in the disease induction. Here we show that administration of the SMO inhibitor to animals has a specific effect directed against the Drosophila ortholog protein, causing loss of quiescence and hematopoietic precursors mobilization. The SMO inhibitor induces in L3 larvae the appearance of melanotic nodules generated as response by Drosophila immune system to the increase of its hemocytes. The same phenotype is induced even by the dsRNA:SMO specific expression in hematopoietic precursors of the lymph gland. The drug action is also confirmed at cellular level. The study of molecular markers has allowed us to demonstrate that SMO inhibitor leads to a reduction of the quiescent precursors and to an increase of the differentiated cells. Moreover administering the inhibitor to heterozygous for a null allele of Smo, we observe a significant increase in the phenotype penetrance compared to administration to wild type animals. This helps to confirm the specific effect of the drug itself. These data taken together indicate that the study of inhibitors of Smo in Drosophila can represent a useful way to dissect their action mechanism at the molecular-genetic level in order to collect information applicable to the studies of the disease in humans.

Rural governance and livelihoods systems diversification in the Western Balkans: comparative case studies of Bosnia and Herzegovina, Montenegro and Serbia

Agriculture is still important for socio-economic development in rural areas of Bosnia, Montenegro and Serbia (BMS). However, for sustainable rural development rural economies should be diversified so attention should be paid also to off-farm and non-farm income-generating activities. Agricultural and rural development (ARD) processes and farm activity diversification initiatives should be well governed. The ultimate objective of this work is to explore linkages between ARD governance and rural livelihoods diversification in BMS. The thesis is based on an extended secondary data analysis and surveys. Questionnaires for ARD governance and coordination were sent via email to public, civil society and international organizations. Concerning rural livelihood diversification, the field questionnaire surveys were carried out in three rural regions of BMS. Results show that local rural livelihoods are increasingly diversified but a significant share of households are still engaged in agriculture. Diversification strategies have a chance to succeed taking into consideration the three rural regions’ assets. However, rural households have to tackle many problems for developing new income-generating activities such as the lack of financial resources. Weak business skills are also a limiting factor. Fully exploiting rural economy diversification potential in BMS requires many interventions including improving rural governance, enhancing service delivery in rural areas, upgrading rural people’s human capital, strengthening rural social capital and improving physical capital, access of the rural population to finance as well as creating a favourable and enabling legal and legislative environment fostering diversification. Governance and coordination of ARD policy design, implementation and evaluation is still challenging in the three Balkan countries and this has repercussions also on the pace of rural livelihoods diversification. Therefore, there is a strong and urgent need for mobilization of all rural stakeholders and actors through appropriate governance arrangements in order to foster rural livelihoods diversification and quality of life improvement.