Exponential depletion of neutral dangling bonds density (D-0) by rare-earth doping in amorphous Si films

In this work we study the effect reduction in the density of dangling bond species D-0 states in rare-earth (RE) doped a-Si films as a function concentration for different RE-specimens. The films a-Si-1_(x) REx, RE=Y3+, Gd3+, Er3+, Lu3+) were prepared by co-sputtering and investigated by electron spin resonance (ESR) and Raman scattering experiments. According to our data the RE-doping reduces the ESR signal intensity of the D-0 states with an exponential dependence on the rare-concentration. Furthermore, the reduction produced by the magnetic rare-earths Gd3+ and Er3+ is remarkably greater than that caused by Y3+ and Lu3+, which led us to suggest an exchange-like coupling between the spin of the magnetic REs3+ and the spin of silicon neutral dangling bonds. (C) 2011 Elsevier B.V. All rights reserved.

Influenza delle caratteristiche quali-quantitative della luce da fonti artificiali sulla fisio-morfologia di piante verdi per interior landscaping

La conoscenza delle esigenze luminose (intensità, spettro, durata minima, massima ed ottimale del fotoperiodo di illuminazione) e della tolleranza alle condizioni degli interni delle piante ad uso decorativo, è di fondamentale importanza per una giusta tecnica di progettazione (dimensionamento e dislocazione dei punti luce) dell’indoor plantscaping. Il lungo periodo di condizionamento al quale queste piante vengono sottoposte, caratterizzato principalmente dalla scarsa disponibilità di luce naturale e dagli alti livelli di concentrazione di CO2 determina una forte influenza sui processi morfo-fisiologici. Il presente studio analizza il fattore luminoso ed è articolato su più punti quali; • caratterizzazione della riposta fotosintetica all’intensità luminosa di 21 delle principali specie a fogliame decorativo comunemente utilizzate nella realizzazione degli spazi verdi indoor, per stabilire quali siano i minimi ed ottimali livelli di PAR tali da garantire una fotosintesi netta positiva e nel complesso le condizioni di maggior benessere per le piante; • quantificazione dell’incremento fotosintetico netto dovuto ad una maggior concentrazione di CO2 negli interni rispetto alla concentrazione CO2 atmosferica esterna, all’aumentare dell’ intensità luminosa artificiale sulle precedenti specie; • monitoraggio dell’andamento delle attività fotosintetiche durante il periodo di illuminazione di 8 ore comunemente utilizzato in un interno ad uso lavorativo, a PAR costante e variabile in Ficus elastica e Dieffenbachia picta, al fine di stabilire quali possano essere le durate e le modalità di somministrazione della luce per rendere massima la fotosintesi netta riducendo al minimo i consumi energetici dovuti all’accensione delle lampade; • valutazione della risposta morfo-fisiologica e fotosintetica a modificazioni dello spettro luminoso mediante l’uso di LED monocromatici colorati ad emissione nel bianco, blu e rosso in Ficus benjamina e Iresine herbistii al fine di stabilire se questo tipo di lampade possano essere utilizzate come fonte integrativa e/o sostitutiva nella realizzazione degli spazi verdi interni. Vengono analizzati il punto si compensazione alla luce (g), il punto di saturazione alla luce (s), l’efficienza quantica (AQE), il punto di respirazione al buio (Rd) e la fotosintesi netta massima (A max) per (Aglaonema commutatum, Asplenium nidus, Anthurium andreanum, Begonia rex, Calathea luoise, Calathea veitchiana, Calathea rufibarba, Calathea zebrina, Codiaeum variegatum, Cthenanthe oppenheimiana, Dieffenbakia picta, Ficus benjamina, Ficus elatica, Ficus longifolia, Fittonia verschaffeltii, Iresine herbistii, Philodendron erubescens, Philodendron pertusum, Potos aureus, Spathiphillum wallisi, Syngonium podophillum ) e classificate le specie in funzione di Amax in quattro categorie; A max < 2 µmol CO2 m-2 s-1, A max compresa tra 2 e 4 µmol CO2 m-2 s-1, Amax cpmpresa tra 4 e 6 µmol CO2 m-2 s-1, Amax > 6 µmol CO2 m-2 s-1, al fine di mettere in risalto la potenzialità fotosintetiche di ogni singola specie. I valori di PAR compresi tra (g) ed (s) forniscono le indicazioni sulle quali basarsi per scegliere una giusta lampada o dimensionare un punto luce per ogni singola specie e/o composizione. È stimata l’influenza di due livelli di concentrazione di CO2 ambientale (400 e 800 ppm) all’incrementare dell’intensità luminosa sul processo fotosintetico delle specie precedenti. Per quasi tutte le specie 800 ppm di CO2 non favoriscono nessun incremento all’attività fotosintetica ad eccezione di Ficus benjamina, Ficus elatica e Syngonium podophillum se non accompagnati da una disponibilità luminosa superiore alle 10 µmol m-2 s-1. Viene monitorato l’andamento dell’attività fotosintetica a PAR costante e variabile (intervallando periodi di 8 minuti a PAR 40 e 80) durante 8 ore di illuminazione su Ficus elastica e Dieffenbachia picta al fine di stabilire la miglior modalità di somministrazione della luce. La fotosintesi netta cumulativa per l’intera durata di illuminazione a PAR costante mostra un calo dopo alcune ore dall’attivazione in Dieffenbackia, e un andamento oscillatorio in Ficus. L’illuminazione alternata consente di raggiungere i quantitativi di CO2 organicata a 80 µmol m-2 s-1 di PAR, dopo 5 ore e mezza sia in Ficus che Dieffenbackia sebbene le potenzialità fotosintetiche delle due piante siano molto differenti. È stato valutato l’effetto dell’illuminazione artificiale mediante LED (15W) a luce bianca, blu e rossa monocromatica in rapporto alla luce neon(36W) bianca tradizionale (con differenti abbinamenti tra le lampade) sui principali parametri morfologici e fisiologici, in Ficus benjamin ‘Variegata’ e Iresine herbistii per verificare se tali fonti possono rappresentare una valida alternativa nella sostituzione o integrazione di altre lampade per gli spazi verdi indoor. Tutte le combinazioni LED indagate possono rappresentare un’alternativa di sostituzione alla coltivazione con neon ed un risparmio energetico di oltre il 50%. Una PAR di 20,6 µmol m-2 s-1 della singola lampada LED bianco è sufficiente per mantenere la pianta in condizioni di sopravvivenza con un consumo di 15W a fronte dei 36W necessari per il funzionamento di ogni neon. La combinazione LED bianco + LED blu monocromatico favorisce il contenimento della taglia della pianta, caratteristica gradita nella fase di utilizzo indoor, una maggior produzione di sostanza secca e un’attività fotosintetica più elevata.

Tetracycline-inducible RNAi Knockdown of SCL (Stem Cell Leukaemia) in Mice

RNAi (RNA interference) is a powerful technology for sequence-specific targeting of mRNAs. This thesis was aimed at establishing conditions for conditional RNAi-mediated silencing first in vitro and subsequently also in transgenic mice. As a target the basic helix-loop-helix transcription factor encoding gene SCL (stem cell leukaemia also known as Tal-1 or TCL5) was used. SCL is a key regulator for haematopoietic development and ectopic expression of SCL is correlated with acute T-lymphoblastic leukaemias. Loss of SCL function studies demonstrated that ab initio deletion of SCL resulted in embryonic lethality around day E9 in gestation. To be able to conditionally inactivate SCL, RNAi technology was combined with the tetracycline-dependent regulatory system. This strategy allowed to exogenously control the induction of RNAi in a reversible fashion and consequently the generation of a completely switchable RNAi knockdown. First a suitable vector allowing for co-expression of tetracycline-controlled shRNAs (small hairpin RNAs) and constitutively active EGFP (enhanced green fluorescent protein) was generated. This novel vector, pRNAi-EGFP, was then evaluated for EGFP expression and tetracycline-mediated expression of shRNAs. Four sequences targeting different regions within the SCL mRNA were tested for their efficiency to specifically knockdown SCL. These experiments were performed in M1 murine leukaemia cells and subsequently in the HEK 293 cell line, expressing an engineered HA-tagged SCL protein. The second assay provided a solid experimental method for determining the efficiency of different SCL-siRNA knockdown constructs in tissue culture. Western blotting analyses revealed a down regulation of SCL protein for all four tested SCL-specific target sequences albeit with different knockdown efficiencies (between 25% and 100%). Furthermore, stringent tetracycline-dependent switchability of shRNA expression was confirmed by co-transfecting the SCL-specific pRNAi-EGFP vector (SCL-siRNA) together with the HA-tagged SCL expression plasmid into the HEK 293TR /T-REx cell line constitutively expressing the tetracycline repressor (TetR). These series of experiments demonstrated tight regulation of siRNA expression without background activity. To be able to control the SCL knockdown in vivo and especially to circumvent any possible embryonic lethality a transgenic mouse line with general expression of a tetracycline repressor was needed. Two alternative methods were used to generate TetR mice. The first approach was to co-inject the tetracycline-regulated RNAi vector together with a commercially available and here specifically modified T-REx expression vector (SCL-siRNA T-REx FRT LoxP mouse line). The second method involved the generation of a TetR expressor mouse line, which was then used for donating TetR-positive oocytes for pronuclear injection of the RNAi vector (SCL-siRNA T-REx mouse line). As expected, and in agreement with data from conditional Cre-controlled adult SCL knockout mice, post-transcriptional silencing of SCL by RNAi caused a shift in the maturation of red blood cell populations. This was shown in the bone marrow and peripheral blood by FACS analysis with the red blood cell-specific TER119 and CD71 markers which can be used to define erythrocyte differentiation (Lodish plot technique). In conclusion this study established conditions for effective SCL RNAi-mediated silencing in vitro and in vivo providing an important tool for further investigations into the role of SCL and, more generally, of its in vivo function in haematopoiesis and leukaemia. Most importantly, the here acquired knowledge will now allow the establishment of other completely conditional and reversible knockdown phenotypes in mice.

Il vocabolario del potere fra intento etico-morale e tutela sociale. I lemmi dei Capitolari Carolingi nel Regnum Italicum (774-813)

Il vocabolario del potere fra intento etico-morale e tutela sociale. I lemmi dei Capitolari Carolingi nel Regnum Italicum (774-813), costituisce il risultato di una ricerca condotta sul lessico della legislazione carolingia promulgata per il Regno Italico dal momento della conquista dei Franchi sino alla morte di Carlomagno. L’analisi ha preso in esame tutti i lemmi, soprattutto sostantivi e aggettivi, riconducibili alla sfera etica e morale, e alla concezione della libertà della persona. Il lavoro si è giovato delle analisi più specifiche in merito ai concetti giuridico-istituzionali che fonti normative come quelle prese in esame portano inevitabilmente in primo piano. La ricerca, partita da una completa catalogazione dei lemmi, si è concentrata su quelli che maggiormente consentissero di valutare le interazioni fra la corte intellettuale dei primi carolingi – formata come noto da uomini di chiesa – e le caratteristiche di pensiero di quegli uomini, un pensiero sociale e istituzionale insieme. Il lavoro ha analizzato un lessico specifico per indagare come la concezione tradizionale della societas Christiana si esprimesse nella legislazione attraverso lemmi ed espressioni formulari peculiari: la scelta di questi da parte del Rex e della sua cerchia avrebbe indicato alla collettività una pacifica convivenza e definito contestualmente “l’intento ordinatore e pacificatore” del sovrano. L’analisi è stata condotta su un periodo breve ma assai significativo – un momento di frattura politica importante – per cogliere, proprio sfruttando la sovrapposizione e talvolta lo scontro fra i diversi usi di cancelleria del regno longobardo prima e carolingio poi, la volontarietà o meno da parte dei sovrani nell’uso di un lessico specifico. Questo diventa il problema centrale della tesi: tale lessico impone con la sua continuità d’uso modelli politici o invece è proprio un uso consapevole e strumentale di un determinato apparato lessicale che intende imporre alla società nuovi modelli di convivenza?

Experimental and Theoretical Study of the OH Vibrational Spectra and Overtone Chemistry of Gas-Phase Vinylacetic Acid

In this study we present the gas-phase vibrational spectrum of vinylacetic acid with a focus on the ν = 1−5 vibrational states of the OH stretching transitions. Cross sections for ν = 1, 2, 4 and 5 of the OH stretching vibrational transitions are derived on the basis of the vapor pressure data obtained for vinylacetic acid. Ab initio calculations are used to assist in the band assignments of the experimental spectra, and to determine the threshold for the decarboxylation of vinylacetic acid. When compared to the theoretical energy barrier to decarboxylation, it is found that the νOH = 4 transition with thermal excitation of low frequency modes or rotational motion and νOH = 5 transitions have sufficient energy for the reaction to proceed following overtone excitation.

Concomitant arginine-vasopressin and hydrocortisone therapy in severe septic shock: association with mortality

To evaluate the association between concomitant arginine-vasopressin (AVP)/hydrocortisone therapy and mortality in severe septic shock patients.

Problem of Tragedy and Tragic Consciousness in Russia at the turn of the 19th Century

This project intertwines philosophical and historico-literary themes, taking as its starting point the concept of tragic consciousness inherent in the epoch of classicism. The research work makes use of ontological categories in order to describe the underlying principles of the image of the world which was created in philosophical and scientific theories of the 17th century as well as in contemporary drama. Using these categories brought Mr. Vilk to the conclusion that the classical picture of the world implied a certain dualism; not the Manichaean division between light and darkness but the discrimination between nature and absolute being, i.e. God. Mr. Vilk begins with an examination of the philosophical essence of French classical theatre of the XVII and XVIII centuries. The history of French classical tragedy can be divided into three periods: from the mid 17th to early 19th centuries when it triumphed all over France and exerted a powerful influence over almost all European countries; followed by the period of its rejection by the Romantics, who declared classicism to be "artificial and rational"; and finally our own century which has taken a more moderate line. Nevertheless, French classical tragedy has never fully recovered its status. Instead, it is ancient tragedy and the works of Shakespeare that are regarded to be the most adequate embodiment of the tragic. Consequently they still provoke a great number of new interpretations ranging from specialised literary criticism to more philosophical rumination. An important feature of classical tragedy is a system of rules and unities which reveals a hidden ontological structure of the world. The ontological picture of the dramatic world can be described in categories worked out by medieval philosophy - being, essence and existence. The first category is to be understood as a tendency toward permanency and stability (within eternity) connected with this or that fragment of dramatic reality. The second implies a certain set of permanent elements that make up the reality. And the third - existence - should be understood as "an act of being", as a realisation of permanently renewed processes of life. All of these categories can be found in every artistic reality but the accents put on one or another and their interrelations create different ontological perspectives. Mr. Vilk plots the movement of thought, expressed in both philosophical and scientific discourses, away from Aristotle's essential forms, and towards a prioritising of existence, and shows how new forms of literature and drama structured the world according to these evolving requirements. At the same time the world created in classical tragedy fully preserves another ontological paradigm - being - as a fundamental permanence. As far as the tragic hero's motivations are concerned this paradigm is revealed in the dedication of his whole self to some cause, and his oath of fidelity, attitudes which shape his behaviour. It may be the idea of the State, or personal honour, or something borrowed from the emotional sphere, passionate love. Mr. Vilk views the conflicting ambivalence of existence and being, duty as responsibility and duty as fidelity, as underlying the main conflict of classical tragedy of the 17th century. Having plotted the movement of the being/existence duality through its manifestations in 17th century tragedy, Mr. Vilk moves to the 18th century, when tragedy took a philosophical turn. A dualistic view of the world became supplanted by the Enlightenment idea of a natural law, rooted in nature. The main point of tragedy now was to reveal that such conflicts as might take place had an anti-rational nature, that they arose as the result of a kind of superstition caused by social reasons. These themes Mr. Vilk now pursues through Russian dramatists of the 18th and early 19th centuries. He begins with Sumarakov, whose philosophical thought has a religious bias. According to Sumarakov, the dualism of the divineness and naturalness of man is on the one hand an eternal paradox, and on the other, a moral challenge for humans to try to unite the two opposites. His early tragedies are not concerned with social evils or the triumph of natural feelings and human reason, but rather the tragic disharmony in the nature of man and the world. Mr Vilk turns next to the work of Kniazhnin. He is particularly keen to rescue his reputation from the judgements of critics who accuse him of being imitative, and in order to do so, analyses in detail the tragedy "Dido", in which Kniazhnin makes an attempt to revive the image of great heroes and city-founders. Aeneas represents the idea of the "being" of Troy, his destiny is the re-establishment of the city (the future Rome). The moral aspect behind this idea is faithfulness, he devotes himself to Gods. Dido is also the creator of a city, endowed with "natural powers" and abilities, but her creation is lacking internal stability grounded in "being". The unity of the two motives is only achieved through Dido's sacrifice of herself and her city to Aeneus. Mr Vilk's next subject is Kheraskov, whose peculiarity lies in the influence of free-mason mysticism on his work. This section deals with one of the most important philosophical assumptions contained in contemporary free-mason literature of the time - the idea of the trinitarian hierarchy inherent in man and the world: body - soul - spirit, and nature - law - grace. Finally, Mr. Vilk assess the work of Ozerov, the last major Russian tragedian. The tragedies which earned him fame, "Oedipus in Athens", "Fingal" and "Dmitri Donskoi", present a compromise between the Enlightenment's emphasis on harmony and ontological tragic conflict. But it is in "Polixene" that a real meeting of the Russian tradition with the age-old history of the genre takes place. The male and female characters of "Polixene" distinctly express the elements of "being" and "existence". Each of the participants of the conflict possesses some dominant characteristic personifying a certain indispensable part of the moral world, a certain "virtue". But their independent efforts are unable to overcome the ontological gap separating them. The end of the tragedy - Polixene's sacrificial self-immolation - paradoxically combines the glorification of each party involved in the conflict, and their condemnation. The final part of Mr. Vilk's research deals with the influence of "Polixene" upon subsequent dramatic art. In this respect Katenin's "Andromacha", inspired by "Polixene", is important to mention. In "Andromacha" a decisive divergence from the principles of the philosophical tragedy of Russian classicism and the ontology of classicism occurs: a new character appears as an independent personality, directed by his private interest. It was Katenin who was to become the intermediary between Pushkin and classical tragedy.

Transatlantic Echoes. Alexander von Humboldt in World Literature

Alexander von Humboldt (1769–1859) was a world traveler, bestselling writer, and versatile researcher, a European salon sensation, and global celebrity. Yet the enormous literary echo he generated has remained largely unexplored. Humboldt inspired generations of authors, from Goethe and Byron to Enzensberger and García Márquez, to reflect on cultural difference, colonial ideology, and the relation between aesthetics and science. This collection of one-hundred texts features tales of adventure, travel reports, novellas, memoirs, letters, poetry, drama, screenplays, and even comics—many for the first time in English. The selection covers the foundational myths and magical realism of Latin America, the intellectual independence of Emerson, Thoreau, Poe, and Whitman in the United States, discourses in Imperial, Weimar, Nazi, East, and West Germany, as well as recent films and fiction. This documented source book addresses scholars in cultural and postcolonial studies as well as readers in history and comparative literature.

Cosmos and Colonialism. Alexander von Humboldt in Cultural Criticism

Alexander von Humboldt explored the Spanish Empire on the verge of its collapse (1799–1804). He is the most significant German travel writer and the most important mediator between Europe and the Americas of the nineteenth century. His works integrated knowledge from two dozen domains. Today, he is at the center of debates on imperial discourse, postcolonialism, and globalization. This collection of fifty essays brings together a range of responses, many presented here for the first time in English. Authors from Schiller, Chateaubriand, Sarmiento, and Nietzsche, to Robert Musil, Kurt Tucholsky, Ernst Bloch, and Alejo Carpentier paint the historical background. Essays by contemporary travel writers and recent critics outline the current controversies on Humboldt. The source materials collected here will be indispensable to scholars of German, French, and Latin and North American literature as well as cultural and postcolonial studies, history, art history, and the history of science.