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A bioenergetic assessment of photosynthetic growth of Synechocystis sp. PCC 6803 in continuous cultures
Get PDFSynechocystis sp. PCC 6803, a model organism used for bioenergy and bioplastic production, was grown in continuous culture to assess its most important bioenergetic parameters.Biomass yield on light energy of 1.237 g mol photons?\u271 and maintenance energy requirement of 0.00312 mol photons g?\u271 h?\u271 were calculated. This corresponded to a light conversion efficiency of 12.5 %, based on the model of Pirt which was about 35 % lower than the theoretical one based on the stoichiometric equation for the formation of biomass on carbon dioxide, water, and nitrate. The maximum Fv/Fm ratio recorded in the Synechocystis cultures was 0.57; it progressively declined to 0.45 as the dilution rate increased. An over-reduction of reaction centers at a high dilution rate was also recorded, together with an increased VJ phase for the chlorophyll fluorescence transient. In contrast, the chlorophyll optical cross section increased by about 40 % at the fastest dilution rate, and compensated for the decline in Fv/Fm, thus resulting in a constant total photosynthesis rate (photosynthesis plus respiration). Chlorophyll content was maximum at the lowest dilution rate and was 48 % lower at the highest one, while phycocyanin, and total carotenoids decreased by about 42 % and 37 %, respectively. Carotenoid analysis revealed increased echinenone, zeaxanthin, and myxoxanthophyll contents as the dilution rate increased (40.6, 63.8 and 35.5 %, respectively, at the fastest dilution rate). A biochemical analysis of the biomass harvested at each different dilution rates showed no changes in the lipid content (averaging 11.2 ? 0.6 % of the dry weight), while the protein content decreased as the dilution rate increased, ranging between 60.7 ? 1.1 and 72.6 ? 0.6 %. Amino acids pattern did not vary with the dilution rate. Carbohydrate content ranged from 9.4 to 16.2 % with a mean value of 11.2 ? 1.4 %. The present work provides useful information on the threshold of light conversion efficiency in Synechocystis,as well as basic bioenergetic parameter.Background: Synechocystis sp. PCC 6803, a model organism used for bioenergy and bioplastic production, was grown in continuous culture to assess its most important bioenergetic parameters. Results: Biomass yield on light energy of 1.237 g mol photons?1 and maintenance energy requirement of 0.00312 mol photons g?1 h?1 were calculated. This corresponded to a light conversion efficiency of 12.5 %, based on the model of Pirt which was about 35 % lower than the theoretical one based on the stoichiometric equation for the formation of biomass on carbon dioxide, water, and nitrate. The maximum Fv/Fm ratio recorded in the Synechocystis cultures was 0.57; it progressively declined to 0.45 as the dilution rate increased. An over-reduction of reaction centers at a high dilution rate was also recorded, together with an increased VJ phase for the chlorophyll fluorescence transient. In contrast, the chlorophyll optical cross section increased by about 40 % at the fastest dilution rate, and compensated for the decline in Fv/Fm, thus resulting in a constant total photosynthesis rate (photosynthesis plus respiration). Chlorophyll content was maximum at the lowest dilution rate and was 48 % lower at the highest one, while phycocyanin, and total carotenoids decreased by about 42 % and 37 %, respectively. Carotenoid analysis revealed increased echinenone, zeaxanthin, and myxoxanthophyll contents as the dilution rate increased (40.6, 63.8 and 35.5 %, respectively, at the fastest dilution rate). A biochemical analysis of the biomass harvested at each different dilution rates showed no changes in the lipid content (averaging 11.2 ? 0.6 % of the dry weight), while the protein content decreased as the dilution rate increased, ranging between 60.7 ? 1.1 and 72.6 ? 0.6 %. Amino acids pattern did not vary with the dilution rate. Carbohydrate content ranged from 9.4 to 16.2 % with a mean value of 11.2 ? 1.4 %. Conclusions: The present work provides useful information on the threshold of light conversion efficiency in Synechocystis, as well as basic bioenergetic parameters that will be helpful for future studies related to its genetic transformation and metabolic network reconstructi
Il Primo Vocabolario del Bambino: Gesti, Parole e frasi. Valori di riferimento fra 8 e 36 mesi delle Forme complete e delle Forme brevi del questionario MacArthur-Bates CDI
No full text-Il Primo Vocabolario del Bambino (adattamento italiano del MacArthur-Bates Communicative Development Inventory-MB-CDI) ? un questionario per i genitori di bambini fra 8 e 36 mesi. Diffuso in Italia gi? da molti anni, ? utilizzato sia nella ricerca sia nella clinica per lo studio e per la valutazione della comunicazione e del linguaggio in bambini con sviluppo tipico e atipico. In questo manuale sono presentati i nuovi valori di riferimento (per bambini tra 8 e 24 mesi di et?) relativi alla versione originale (Forma completa) della scheda "Gesti e Parole", e quelli relativi ad un nuovo strumento, ad oggi inedito, ovvero la Forma breve della stessa scheda. Sono inoltre riportati i valori di riferimento relativi alle due Forme (completa e breve) della scheda "Parole e Frasi", dati gi? pubblicati con la stessa casa editrice (Caselli, Pasqualetti e Stefanini, 2007). Accanto alla presentazione delle 4 diverse versioni del questionario, alle indicazioni relative alle modalit? di somministrazione, codifi ca e interpretazione dei dati, vengono ripercorse le tappe principali dell\u27acquisizione del linguaggio dei bambini, con particolare attenzione alle differenze individuali e ai meccanismi cognitivi, linguistici e relazionali che entrano in gioco. Queste conoscenze permettono di comprendere meglio la costruzione dello strumento e le sue fi nalit?, facilitando cos? l\u27interpretazione dei valori di riferimento. Nel manuale viene inoltre messo in luce come lo strumento abbia fornito un importante contributo per la ricerca e per la clinica, permettendo di defi nire indicatori di rischio affidabili e condivisi e di realizzare esperienze di prevenzione e screening in alcune parti del territorio italiano
Spelling acquisition in English and Italian: A cross-linguistic study
Get PDFWe examined the spelling acquisition in children up to late primary school of a consistent orthography (Italian) and an inconsistent orthography (English). The effects of frequency, lexicality, length and regularity in modulating spelling performance of the two groups were examined. English and Italian children were matched for both chronological age and number of years of schooling. Two-hundred and seven Italian children and 79 English children took part in the study. We found greater accuracy in spelling in Italian than English children: Italian children were very accurate after only two years of schooling, while in English children the spelling performance was still poor after five years of schooling. Cross-linguistic differences in spelling accuracy proved to be more persistent than the corresponding ones in reading accuracy. Orthographic consistency produced not only quantitative, but also qualitative differences, with larger frequency and regularity effects in English than in Italian children
Neurobiological response to EMDR therapy in clients with different psychological traumas
Get PDFWe assessed cortical activation differences in real-time upon exposure to traumatic memory between two distinct groups of psychologically traumatised clients also in comparison with healthy controls. We used electroencephalography (EEG) to compare neuronal activation throughout the bilateral stimulation phase of Eye Movement Desensitization and Reprocessing (EMDR) sessions. We compared activation between the first (T0) and the last (T1) session, the latter performed after processing the index trauma. The group including all clients showed significantly higher cortical activity in orbito-frontal cortex at T0 shifting at T1 towards posterior associative regions. However the subgroup of clients with chronic exposure to the traumatic event showed a cortical firing at both stages which was closer to that of controls. For the first time EEG monitoring enabled to disclose neurobiological differences between groups of clients with different trauma histories during the reliving of the traumatic event. Cortical activations in clients chronically exposed to traumatic memories were moderate, suggesting an association between social and environmental contexts with the neurobiological response to trauma exposure and psychotherapy
Cortical activity during olfactory stimulation in multiple chemical sensitivity: a 18F-FDG PET/CT study
Get PDFPurpose To investigate the differences in brain glucose consumption during olfactory stimulation between subjects affected by multiple chemical sensitivity (MCS) and a group of healthy individuals. Methods Two 18F-FDG PET/CT scans were performed in 26 subjects (6 men and 20 women; mean age 46.7?11 years) with a clinical diagnosis of MCS and in 11 healthy controls (6 women and 5 men; mean age 45.7?11 years), the first scan after a neutral olfactory stimulation (NS) and the second after a pure olfactory stimulation (OS). Differences in 18F-FDG uptake were analysed by statistical parametric mapping (SPM2). Results In controls OS led to an increase in glucose consumption in BA 18 and 19 and a reduction in glucose metabolism in BA 10, 11, 32 and 47. In MCS subjects, OS led to an increase in glucose consumption in BA 20, 23, 18 and 37 and a reduction in glucose metabolism in BA 8, 9 and 10. Conclusion The results of our study suggest that cortical activity in subjects with MCS differs from that in healthy individuals during olfactory stimulation
Brain metabolic changes in Hodgkin disease patients following diagnosis and during the disease course: An 18F-FDG PET/CT study
Get PDFThe aim of the present study was to investigate brain glucose metabolism in patients with Hodgkin disease (HD) after diagnosis and during chemotherapy treatment. Following the administration of first?\u27line doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) chemotherapy, 74 HD patients underwent 18F?\u27fluoro?\u272?\u27deoxy?\u27D?\u27glucose (18F?\u27FDG) positron emission tomography (PET)/computed tomography brain scans, both baseline (PET0) and interim (PET2) at the Department of Biomedicine and Prevention, University of Rome Tor Vergata (Rome, Italy). Fifty?\u27seven patients were further evaluated 15?6 days after four additional cycles (PET6). Furthermore, a control group (CG) of 40 chemotherapy?\u27na?ve subjects was enrolled. Differences in brain 18F?\u27FDG uptake between the CG, PET0, PET2 and PET6 scans were analyzed using statistical parametric mapping. Compared with the PET0 and CG scans, the PET2 scan demonstrated a higher metabolic activity in Brodmann area (BA) 39, and a metabolic reduction in BA 11 bilaterally and in left BA 32. All of these changes disappeared at PET6. The results of the present study indicate that ABVD chemotherapy has a limited impact on brain metabolism
Experimental study of water-oil-boom interaction and failure events
No full textOil spill caused by maritime accidents can damage valuable ecosystems and have a huge economic impact on fishing and tourism industries. In order to minimize the damage it is important to predict the trajectory of the spilt oil slick and use an effective clean-up strategy. Oil booms represent a valid solution, but their performance has a limitation in sufficiently strong currents and high sea waves. This motivated research efforts in the development of suitable prediction tools useful for the design and for setting the operative limits of these devices. Experiments are instead more difficult to perform. However some relevant studies have been documented along the years, most of them in 2D conditions, with fixed boom and in steady current
Violence and Art
No full textAccording to the Latin poet Virgil, art is capable of revealing to us what no science can ever reveal to a human mind. Due to a countless number of factors, in the course of history, human beings\u27 efforts to fully understand their inner and outer reality have been largely unsuccessful. Though timidly, also scientific research has now suggested that the relationship with art can be a powerful instrument in order to attain a deeper and different comprehension of reality. Violence, or, more exactly, unjustified violence, basically rests on an irrational and short-sighted analysis and interpretation of reality. It is here assumed that the experience of art can provide a powerful contribution in order to understand reality much more deeply, to avoid unjustified violence, and to address conflicts constructively. The psychological processes relating to the experience of art and to its connections with violence are described. It is also pointed out that this theoretical perspective does not perfectly coincide with the theoretical theses underpinning art therapy. It is a fact that in this paper art is not considered as a mere instrument, a perspective that might inadvertently and implicitly suggest the idea of an entity from which human beings, poised in a sort of higher hierarchical level, merely draw a greater capacity to understand reality. Instead, a completely different situation is created when you consider this entity as invaluable, infinite, and mysterious. In this context the two components of the situation - art and human beings - are on the same level. Some suggestions are presented aiming to explain why this theoretical approach might be particularly helpful in order to better understand and countervail violence
Geochemistry, biota and natural background levels in an arsenic naturally contaminated volcanic aquifer
No full textThe tight links between chemical and ecological status are largely acknowledged as for surface water bodies, while aquifers are still considered as hidden groundwater reservoirs, rather than ecosystems to be preserved. Geochemical and biological interactions play a key role in all subterranean processes, including the dynamics of the fate of anthropogenic contaminants. Studies on groundwater dependent ecosystems (GDE) were mainly focused on karst aquifers so far, but an increased awareness on the importance of water-rock interactions and methodological improvements in microbial ecology are rapidly increasing the level of characterization of groundwater ecosystems in various hydrogeological contexts. Similarly, knowledge about groundwater biodiversity is still limited, especially if porous habitats are concerned. Yet, groundwater and GDEs are populated by a diverse and highly adapted biota, dominated by crustaceans, which provide important ecosystem services and act as biological indicators of chemical and quantitative impact on groundwater resources. In a previous research (Amalfitano et al. 2014), we reported that the microbial community heterogeneity may reflect the lithological and hydrogeological complexity within volcanic and alluvial facies transition in a groundwater body. The quantitative tracking of the microbial community structure allowed disentangling the natural biogeochemical processes evolving within the aquifer flow path. The analyses of groundwater crustaceans assemblages may contribute to shed more light upon the state and dynamics of such ecosystems. In the present research, a comprehensive study of a water table aquifer flowing through a quaternary volcanic district is being performed, including the geochemical (inorganic) composition, the microbial composition, and the analysis of crustacean assemblages. Groundwater samples are periodically collected from private wells and springs under a low anthropic impact. The key issues within the sampling area are related to occurrence of arsenic from natural sources, fluoride and coliforms, which make the water resource unsuitable for human consumption. The aim of this work is to present the first outcomes of this activit