Sviluppo di biosaggi basati sulla sinesi di fitochelatine in microalghe fitoplanctoniche marine, per la valutazione ecotossicologica di sedimenti costieri contaminati da metalli pesanti.

I metalli pesanti come zinco, rame, cadmio, mercurio, nichel e cobalto sono elementi ubiquitari nell'ambiente pur essendo componenti minori della biosfera. Essi sono per lo più sequestrati nei sedimenti, nel suolo e nei giacimenti minerari, ma, per effetto di attività antropiche, la loro concentrazione nei vari comparti ambientali può aumentare di vari ordini di grandezza e, direttamente o attraverso la catena alimentare, possono accumularsi nei tessuti degli organismi viventi. Nell’acqua di mare i metalli pesanti possono essere complessati con molecole organiche ed inorganiche che ne influenzano la biodisponibilità e quindi la tossicità. Nel corso dell’evoluzione i microrganismi acquatici hanno sviluppato molteplici strategie di adattamento per neutralizzare gli effetti tossici dovuti ad una presenza eccessiva di metalli nelle acque. I principali meccanismi di detossificazione conosciuti a tutt’oggi si basano sulla strategia di limitare nella cellula la presenza di ioni metallici tossici liberi. Il mio internato di tesi riguarda lo studio dei meccanismi di difesa messi in atto da microalghe fitoplanctoniche in risposta alla presenza di metalli pesanti mediante la produzione di fitochelatine. Le fitochelatine sono polipeptidi caratterizzati dalla presenza di un elevato numero di residui cisteinici con struttura primaria: (γ-Glu-Cys)n-Gly, con n che varia normalmente da 2 a 6; questi peptidi intracellulari, polimeri del glutatione, sono capaci di sequestrare in complessi stabili il metallo potenzialmente tossico. Mediante l’uso di una tecnica cromatografica per la misura dei tioli non proteici basata sulla derivatizzazione pre-colonna con una sonda fluorescente reattiva, il monobromobimano (mBrB), e sulla separazione dei peptidi tramite HPLC con colonna a fase inversa, sono stati condotti esperimenti esponendo microalghe marine a concentrazioni note di Cd, Cu, Pb e Zn e quantificando il pool di fitochelatine cellulari in saggi a breve termine. Le microalghe utilizzate sono il Phaeodactylum tricornutum, la Thalassiosira weissflogii e la Skeletonema costatum (diatomee), la Dunaliella tertiolecta, (alga verde) e l’Emiliania huxleyi (coccolitoforide). I primi risultati ottenuti hanno mostrato che la concentrazione di fitochelatine cellulari aumenta con l'aumentare della concentrazione degli ioni metallici liberi nel mezzo, indicando così che la produzione di fitochelatine è una risposta cellulare alla frazione di metallo biodisponibile, costituita dalla forma inorganica del metallo stesso. Utilizzando questi sistemi controllati, sono stati condotti esperimenti preliminari per valutare la possibilità di utilizzare il pool intracellulare dei tioli non proteici (glutatione e fitochelatine) come biomarker di esposizione a specie potenzialmente tossiche di metalli, quali Cd, Pb, Cu, Zn, applicando questi biosaggi algali ad acque ed elutriati di sedimenti prelevati in aree costiere a forte impatto antropico. Il mio lavoro di tesi è rivolto, in particolare, all’analisi degli elutriati ottenuti da sedimenti prelevati nelle aree della Foce dello Scolmatore e di Marina di Pisa

Vitalism and desubjectivation: The prudence ethics in Gilles Deleuze

En el marco del debate sobre los lineamientos fundamentales de la ética de Deleuze, diversos autores (Badiou, Braidotti, Hardt, Mengue) han reparado en nociones destacadas de su obra: el deseo, el devenir, la afirmación, el nomadismo. Mi propuesta en este artículo es desarrollar una vía poco estudiada, que gira alrededor de la idea de prudencia práctica experimental. Según mi hipótesis, este concepto reúne perspectivas relevantes de la producción deleuzeana posterior a L'Anti-Œdipe, en particular su orientación vitalista, su opción por la desubjetivación y su apelación a una dimensión ascética vinculada con el deseo como impulsor de la experimentación.Within the realm of debate on fundamental layouts of Deleuze's ethics, several authors (Badiou, Braidotti, Hardt, Mengue) have concentrated on significant notions in his work: desire, becoming, affirmation, nomadism. In this article my proposal is to develop a road, scarcely studied yet, in connection with the idea of experimental practical prudence. Respect to my hypothesis, this concept assembles relevant perspectives of Deleuze's post L'Anti-Œdipe production, especially his orientation towards vitalism, his choice for desubjectivation and his appeal to an ascetic dimension linked to desire as motor to experimentation.Fil: Antonelli Marangi, Marcelo Sebastián. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Filosofía "Dr. Alejandro Korn"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Roberto Esposito’ s Deleuzian Trend

En este trabajo abordamos los conceptos de Gilles Deleuze presentes en la obra de Roberto Esposito. Tras décadas en las que el pensamiento del francés había sido poco estudiado o bien criticado por la filosofía italiana, la irrupción del paradigma biopolítico le otorgó un nuevo protagonismo a causa de su lectura de Foucault. La interpretación de Toni Negri del biopoder a través de la óptica de la sociedad de control, así como la elaboración de una biopolítica afirmativa por parte de Esposito, constituyen ejemplos de ello. Ahora bien, Esposito ha recurrido a la obra deleuziana cada vez más en sus producciones posteriores a Bíos, a propósito de temas diversos: en Terza Persona se apoya en su concepción del acontecimiento a fin de fundamentar su filosofía de lo impersonal, mientras que en Due emplea la idea de “plano de inmanencia” para desconstruir la máquina teológico-política. Nuestro objetivo es analizar el uso espositiano de los conceptos deleuzianos en estos textos, donde vincula perspectivas del francés con problemáticas diferentes a las de los textos de origen. Esposito lleva a cabo de esta manera, antes que una lectura exegética de Deleuze, un empleo novedoso de sus nociones que le permite reformular los problemas planteados.This work tackles Gilles Deleuze’s concepts present in Roberto Esposito’s writings. After decades of being ostracized, overlooked or even criticized by the Italian Philosophy, the French’s thought gained brand new protagonism with the birth of the Biopolitical paradigm, due to his understanding of Foucault. Toni Negri’s interpretation of Biopower from the society of control’s point of view, as well as Esposito’s elaboration of affirmative Biopolitics constitute clear examples. Esposito has increasingly recurred to Deleuze’s work for his subsequent productions to Bios on several matters: in Terza Persona he relies on his conception of event so as to support his philosophy of the impersonal; whereas in Due he brings into play the idea of “plane of immanence” to deconstruct the theological-political machine. Our aim is to analyze Esposito’s use of Deleuze’s concepts in his texts, in which he intertwines the French’s perspective with a different problematic present in the original texts. Thus, Esposito performs a fresh usage of his notions, which enables him to reformulate the addressed mattersFil: Antonelli Marangi, Marcelo Sebastián. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Filosofía "Dr. Alejandro Korn"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Design and Techno-Economical Optimization of Wind Turbine Generator System: Under Diverse Metrological Conditions

The Kenyan Electricity Supply Industry (KESI) generation mix comprises; hydro-electric, geothermal, thermal and a small contribution from wind energy. Over the years, the predominant source of electricity generation in KESI has been hydro (over 60%). However, due to climate changes in recent times hydro generation has become less reliable and largely contributed to the supply–demand mismatch. Against this background there has been a paradigm shift in energy policy towards the use of Renewable Energy sources for electricity generation. Informed by this shift of policy, this paper explores the possibility of generating electrical power from wind-at Mokowe, Lamu County, in Kenya along the Indian Ocean. The paper contends that the use of optimally designed Wind Turbine Generators (WTGs) could enhance production of electrical power at the proposed site. This in effect would significantly: improve the technical and economic performance of KESI; and impact positively on the socio-economic status of the local communities at Makowe

Genome-Wide Expression Analysis of Glyoxalase I Genes Under Hyperosmotic Stress and Existence of a Stress-Responsive Mitochondrial Glyoxalase I Activity in Durum Wheat (Triticum durum Desf.)

Glyoxalase I (GLYI) catalyzes the rate-limiting step of the glyoxalase pathway that, in the presence of GSH, detoxifies the cytotoxic molecule methylglyoxal (MG) into the non-toxic D-lactate. In plants, MG levels rise under various abiotic stresses, so GLYI may play a crucial role in providing stress tolerance. In this study, a comprehensive genome database analysis was performed in durum wheat (Triticum durum Desf.), identifying 27 candidate GLYI genes (TdGLYI). However, further analyses of phylogenetic relationships and conserved GLYI binding sites indicated that only nine genes encode for putative functionally active TdGLYI enzymes, whose distribution was predicted in three different subcellular compartments, namely cytoplasm, plastids and mitochondria. Expression profile by qRT-PCR analysis revealed that most of the putative active TdGLYI genes were up-regulated by salt and osmotic stress in roots and shoots from 4-day-old seedlings, although a different behavior was observed between the two types of stress and tissue. Accordingly, in the same tissues, hyperosmotic stress induced an increase (up to about 40%) of both GLYI activity and MG content as well as a decrease of GSH (up to about –60%) and an increase of GSSG content (up to about 7-fold) with a consequent strong decrease of the GSH/GSSG ratio (up to about –95%). Interestingly, in this study, we reported the first demonstration of the existence of GLYI activity in highly purified mitochondrial fraction. In particular, GLYI activity was measured in mitochondria from durum wheat (DWM), showing hyperbolic kinetics with Km and Vmax values equal to 92 ± 0.2 μM and 0.519 ± 0.004 μmol min(–1) mg(–1) of proteins, respectively. DWM–GLYI resulted inhibited in a competitive manner by GSH (Ki = 6.5 ± 0.7 mM), activated by Zn(2+) and increased, up to about 35 and 55%, under salt and osmotic stress, respectively. In the whole, this study provides basis about the physiological significance of GLYI in durum wheat, by highlighting the role of this enzyme in the early response of seedlings to hyperosmotic stress. Finally, our results strongly suggest the existence of a complete mitochondrial GLYI pathway in durum wheat actively involved in MG detoxification under hyperosmotic stress

Splitting and composition methods for explicit time dependence in separable dynamical systems

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On the dynamics of a generalized predator-prey system with Z-type control.

We apply the Z-control approach to a generalized predator prey system and consider the specific case of indirect control of the prey population. We derive the associated Z-controlled model and investigate its properties from the point of view of the dynamical systems theory. The key role of the design parameter A. for the successful application of the method is stressed and related to specific dynamical properties of the Z-controlled model. Critical values of the design parameter are also found, delimiting the lambda-range for the effectiveness of the Z-method. Analytical results are then numerically validated by the means of two ecological models: the classical Lotka-Volterra model and a model related to a case study of the wolf wild boar dynamics in the Alta Murgia National Park. Investigations on these models also highlight how the Z-control method acts in respect to different dynamical regimes of the uncontrolled model. (C) 2016 The Authors. Published by Elsevier Inc

Role of the annealing parameters on the resistance of indium tin oxide nanocrystalline films

The optical and electrical properties of films made of nanoparticles of indium tin oxide (ITO) are widely studied because of the significance of this material for transparent electrodes, smart windows, and nonlinear optics components. In this work, a systematic study of the resistance in ITO nanocrystalline films, as a function of post-fabrication parameters, such as the temperature and time of annealing, has been performed. A tunability of the resistance with the annealing parameters, in a range of three orders of magnitude, has been demonstrated. The optical properties of the nanocrystalline films were also evaluated as a function of the same parameters. Results show a different influence of temperature and time on the modification of the absorption properties. Temperature and time can be used synergistically to obtain thin films with desired optical and electrical properties through post-fabrication treatments

Laminin-1 redistributes postsynaptic proteins and requires rapsyn, tyrosine phosphorylation, and Src and Fyn to stably cluster acetylcholine receptors

Clustering of acetylcholine receptors (AChRs) is a critical step in neuromuscular synaptogenesis, and is induced by agrin and laminin which are thought to act through different signaling mechanisms. We addressed whether laminin redistributes postsynaptic proteins and requires key elements of the agrin signaling pathway to cause AChR aggregation. In myotubes, laminin-1 rearranged dystroglycans and syntrophins into a laminin-like network, whereas inducing AChR-containing clusters of dystrobrevin, utrophin, and, to a marginal degree, MuSK. Laminin-1 also caused extensive coclustering of rapsyn and phosphotyrosine with AChRs, but none of these clusters were observed in rapsyn −/− myotubes. In parallel with clustering, laminin-1 induced tyrosine phosphorylation of AChR β and δ subunits. Staurosporine and herbimycin, inhibitors of tyrosine kinases, prevented laminin-induced AChR phosphorylation and AChR and phosphotyrosine clustering, and caused rapid dispersal of clusters previously induced by laminin-1. Finally, laminin-1 caused normal aggregation of AChRs and phosphotyrosine in myotubes lacking both Src and Fyn kinases, but these clusters dispersed rapidly after laminin withdrawal. Thus, laminin-1 redistributes postsynaptic proteins and, like agrin, requires tyrosine kinases for AChR phosphorylation and clustering, and rapsyn for AChR cluster formation, whereas cluster stabilization depends on Src and Fyn. Therefore, the laminin and agrin signaling pathways overlap intracellularly, which may be important for neuromuscular synapse formation