Effetto dell'acqua sulla reazione di attivazione nella polimerizzazione radicalica per trasferimento d'atomo

ATRP is a powerful method for the synthesis of polymeric materials with well controlled architectures, molecular weight and polydispersity. The control is ensured by an equilibrium between the dormant species and the propagating radical, catalyzed by copper complexes with polydentate amine ligands. The equilibrium is strongly shifted toward the dormant species, so the concentration of the radical is very low, thus sharply reducing the rate of termination reactions. The activation reaction plays a crucial role in the polymerization process and it is strongly affected by the reaction medium. In particular, the rate constant of the activation reaction depends on the nature of the copper complex, on the solvent and on the monomer. In this thesis project, several electrochemical metods will be employed to provide insights onto the kinetics of the activation reaction, by analysing different catalysts in a range of solvents, both with and without (i) some monomers, (ii) small amounts of water and (iii) halide ions.openTESI.380

Informal payments and performance in the health care sector: possible relationships in a sub-national perspective

The paper explores the relationship between corruption and performance dimensions of the Italian regional health care systems (RHSs). In Europe, Italy shows the widest sub-national in performance and corruption levels. The research focuses on petty corruption in health care. So-called informal payments are the most common form and were measured using data from the European Quality of Government Index Survey. The performance of Italian RHSs was assessed using key indicators divided into three analytical dimensions: health status; access to care; and quality of care. OECD Health Data was used as source data for health status and access to care. As a proxy for quality of care, the study used avoidable mortality, with data drawn from the Italian National Institute of Statistics (ISTAT). The study formulated a research hypothesises that petty corruption has a negative influence on RHS performance. The findings showed considerable regional differences. The results did not confirm the research hypotheses. However, informal payments did show an adverse effect on renunciations to specialist medical examinations due to costs

Somatostatin coupling to adenylyl cyclase activity in the mouse retina

The peptide somatostatin-14 (SRIF) acts in the mammalian retina through its distinct receptors (sst1-5). Scarce information is available on SRIF function in the retina, including the elucidation of transduction pathways mediating SRIF action. We have investigated SRIF and SRIF receptor modulation of adenylyl cyclase (AC) activity in both wild type (WT) retinas and sst1 or sst2 knock-out (KO) retinas which are known to over-express sst2 or sst1 receptors, respectively. In WT retinas, application of SRIF compounds does not affect forskolin-stimulated AC activity. In contrast, activation of sst1 or sst2 receptors inhibits AC in the presence of sst2 or sst1 receptor antagonists, respectively. Results from sst1 KO retinas demonstrate that either SRIF or octreotide, pertussis toxin-dependently inhibit AC activity. In contrast, in sst2 KO retinas, neither SRIF nor CH-275, an sst1 receptor agonist, are found to influence AC activity. As revealed by immunoblotting experiments, in sst1 KO retinas, levels of Goα proteins are 60% higher than in WT retinas and this increase in Goα protein levels is concomitant with an increase in sst2A receptor expression. We conclude that interactions between sst1 and sst2 receptors may prevent SRIF effects on AC activity. In addition, we suggest that the density of sst2 receptors and/or Goα proteins may represent the rate-limiting factor for the sst2 receptor-mediated inhibition of AC.L'articolo è disponibile sul sito dell'editore http://www.springerlink.com

Reattore anaerobico a membrana: produzione di biometano da pollina ed effluente ad elevata qualità

Il presente progetto prevede lo studio approfondito di un sistema integrato per la produzione di biometano da pollina, accoppiando un bioreattore anaerobico a membrana (AnMBR) allo strippaggio dell’ammoniaca che viene assorbita in una soluzione di acido solforico, ottenendo così solfato di ammonio. Le prove sono state effettuale utilizzando un reattore in scala pilota (30 L), sotto condizioni mesofile (37°C), impiegando un carico organico volumetrico (OLR) tra 1,0 e 7,6 kgVS/m3/giorno e HRT tra 9 e 49 giorni. I risultati ottenuti dal processo di digestione anaerobica seguito da strippaggio dell’ammoniaca e ricircolo del permeato, mostrano rese in metano tra il 60 e 75%, una produzione specifica di gas media di 0,59 m3biogas/kgVS e un tenore di sCOD in uscita sotto i 3000 mgO2/L

Biological activity of somatostatin receptors in GC rat tumour somatotrophs: evidence with sst1-sst5 receptor-selective nonpeptidyl agonists

The physiological actions of somatostatin-14 (SRIF) receptor subtypes (sst1-sst5), which are endogenously expressed in GC cells, have not yet been elucidated, although there is evidence that sst2 receptors are negatively coupled to cytosolic free Ca2+ concentration ([Ca2+]i) and cAMP accumulation. In addition, both sst1 and sst2 receptors are negatively coupled to growth hormone (GH) secretion in GC cells. Here we report on studies concerning the expression, the pharmacology and the functional role of native SRIF receptors in GC cells with the use of five nonpeptidyl agonists, highly selective for each of the SRIF receptors. Radioligand binding studies show that sst2 and sst5 receptors are present at different relative densities, while the presence of sst3 and sst4 receptors appears to be negligible. The absence of sst1 receptor binding was unexpected in view of sst1 receptor functional effects on GH secretion. This suggests very efficient receptor-effector coupling of a low density population of sst1 receptors. Functionally, only sst2 receptors are coupled to the inhibition of [Ca2+]i and cAMP accumulation and the selective activation of sst5 receptors facilitates the stimulation of adenylyl cyclase activity through Gi/o proteins. This effect was not observed when sst2 and sst5 receptors were simultaneously activated, suggesting that there is a functional interaction between sst2 and sst5 receptors. In addition, sst1, sst2 and sst5 receptor activation inhibits GH release, further indicating that SRIF can modulate GH secretion in GC cells through mechanisms both dependent and independent on [Ca2+]i and cAMP-dependent pathways. The present data suggest SRIF-mediated functional effects in GC cells to be very diverse and provide compelling arguments to propose that multiple native SRIF receptors expressed in the same cells are not simply redundant, but contribute to marked signalling diversity.L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com

Two-dimensional gel proteome reference map of human small intestine

<p>Abstract</p> <p>Background</p> <p>The small intestine is an important human organ that plays a central role in many physiological functions including digestion, absorption, secretion and defense. Duodenal pathologies include, for instance, the ulcer associated to Helicobacter Pylori infection, adenoma and, in genetically predisposed individuals, celiac disease. Alterations in the bowel reduce its capability to absorb nutrients, minerals and fat-soluble vitamins. Anemia and osteopenia or osteoporosis may develop as a consequence of vitamins malabsorption. Adenoma is a benign tumor that has the potential to become cancerous. Adult celiac disease patients present an overall risk of cancer that is almost twice than that found in the general population. These disease processes are not completely known.</p> <p>To date, a two dimensional (2D) reference map of proteins expressed in human duodenal tissue is not yet available: the aim of our study was to characterize the 2D protein map, and to identify proteins of duodenal mucosa of adult individuals without duodenal illness, to create a protein database. This approach, may be useful for comparing similar protein samples in different laboratories and for the molecular characterization of intestinal pathologies without recurring to the use of surgical material.</p> <p>Results</p> <p>The enrolled population comprised five selected samples (3 males and 2 females, aged 19 to 42), taken from 20 adult subjects, on their first visit at the gastroenterology unit for a suspected celiac disease, who did not turn to be affected by any duodenal pathology after gastrointestinal and histological evaluations. Proteins extracted from the five duodenal mucosal specimens were singly separated by 2D gel electrophoresis. After image analysis of each 2D gel, 179 protein spots, representing 145 unique proteins, from 218 spots tested, were successfully identified by MALDI-TOF ms analysis. Normalized volumes, for each protein, have been reported for every gel. Proteins have been grouped according to their biological/metabolic functions.</p> <p>Conclusion</p> <p>This study represents to date the first detailed and reproducible 2D protein map of human duodenum. Spots identifications, reported in a database, will be helpful to identify the variability in protein expression levels, in isoforms expression, or in post-translational modifications associated to pathology or to a therapy.</p