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This thesis describes the effects of the combined incorporation of nitrogen (N) and hydrogen (H) atoms in the narrow gap III-V InAs semiconductor. The plasmonic properties of the dilute nitride In(AsN) alloy are investigated before and after the post-growth incorporation of H-atoms. The hydrogenation of In(AsN) leads to a substantial increase of the electron density near the surface. The optical excitation of In(AsN):H creates a mid-infrared (MIR) surface plasmon polariton (SPP) mode detected by reflectance techniques. The plasmonic response of the highly doped In(AsN):H compound is spatially tailored and suppressed by different techniques, such as laser or electron beam annealing, as probed by Raman spectroscopy and scanning electron microscopy (SEM). This approach enables the control of the electron density of a highly doped semiconductor by changing its chemical composition on the m-scale. Furthermore, the effects of the incorporation of N in the quantum well (QW) layer of an In(AsN)/(InAl)As resonant tunnelling diode (RTD) are presented. We show that the N-incorporation leads to the creation of strongly localized zero-dimensional (0D) states in the band gap of In(AsN). These contribute to an extended and weakly temperature dependent negative differential resistance (NDR) in the current-voltage (I-V) characteristic of the diode, not observed in N-free RTDs. This behaviour is attributed to a new type of Zener tunnelling assisted by N-related 0D states, whose size is probed by magneto-tunnelling experiments. These N-related states also contribute to the tuning of the MIR electroluminescence (EL) of the RTD, which notably also shows the occurrence of up-conversion up to room temperature.

Protein mono-ADP-ribosylation is a reversible post-translational modification that has been implicated in the regulation of different cell functions, including signal transduction, protein trafficking, and immune responses. In mammals, three families of proteins catalyse this reaction: the ecto-monoARTs/ARTCs, some members of the PARP/ARTD family and some members of the sirtuin family. In this study, I have been focused on the characterisation of human P ARP 161 ARTD 15 and hamster cARTC2.1. Moreover, I have set up novel technologies for the study of intracellular ADP- ribosylation reactions. I have shown that PARP16/ARTD15 is a mono-ADP-ribosyl transferase that localises to the endoplasmic reticulum, where it binds karyopherin-B 1, a pivotal nuclear transport receptor. Moreover, I have also shown that PARP16/ARTD15 induces the mono-ADP-ribosylation of karyopherin-B 1, defining the first substrate for this enzyme. These data suggest a novel regulatory mechanism of karyopherin-Bl functions mediated by PARP16/ARTD15 mono-ADP-ribosyl transferase activity. In parallel, I have also characterised the activity and the intracellular localisation of the hamster isoform cARTC2.1. This enzyme has both NAD-glycohydrolase (NADase) and arginine-specific ADP-ribosyltransferase (ART) activities. I have generated a double mutant of cARTC2.1 by substituting both the glutamates of the EKE active-site motif and showed that this mutated protein loses ART activity, while correctly localise to the plasma membrane. Importantly, we have shown that endogenous ADP-ribosyltransferase is indeed expressed and active in a subset of CHO cells. The subset of ART-positive cells, which represented 5% of the total cells, is tightly maintained in the CHO cell population and shows higher level of cARTC2.1 transcript compared to the ART- negative population. Moreover, I have demonstrated that cARTC2.1 catalyses the mono-ADP- ribosylation of GRP78/BiP, a protein with a central role in different cell functions. This finding represents the first demonstration of the ARTC-mediated GRP78/BiP modification. Finally, I have set up experimental conditions for GST-macro domain based approaches. I have shown that the cross-linking of GST-macro domain to the sepharose resin improves ADP- ribosylated substrate isolation and analysis by macro-based pull-down assay. Moreover, I have demonstrated the suitability of GST-macro domain to label endogenous ADP-ribosylated proteins by a far-western blotting approach. These data established that GST -macro domain is a powerful tool in the study of ADP-ribosylation reactions at protein level.

This thesis is a study of the colony of Italian anarchists who found refuge in London in the years between the Paris Commune and the outbreak of the First World War. The first chapter is an introduction to the sources and to the main problems analysed. The second chapter reconstructs the settlement of the Italian anarchists in London and their relationship with the colony of Italian emigrants. Chapter three deals with the activities that the Italian anarchists organised in London, such as demonstrations, conferences, and meetings. It likewise examines the ideological differences that characterised the two main groups in which the anarchists were divided: organisationalists and anti-organisationalists. Italian authorities were extremely concerned about the danger represented by the anarchists. The fourth chapter of the thesis provides a detailed investigation of the surveillance of the anarchists that the Italian embassy and the Italian Minster of Interior organised in London by using spies and informers. At the same time, it describes the contradictory attitude held by British police forces toward political refugees. The following two chapters are dedicated to the analysis of the main instruments of propaganda used by the Italian anarchists: chapter five reviews the newspapers they published in those years, and chapter six reconstructs social and political activities that were organised in their clubs. Chapter seven examines the impact that the outbreak of First World Word had on the anarchist movement, particularly in dividing it between interventionists and anti-interventionists; a split that destroyed the network of international solidarity that had been hitherto the core of the experience of political exile. Chapter eight summarises the main arguments of the dissertation.