Carbon Dioxide degassing at Latera caldera (Italy): evidence of geothermal reservoir and evaluation of its potential energy

In order to test the potentiality of soil CO2 diffuse degassing measurements for the study of underground mass and heat transfer in geothermal systems detailed surveys were performed at Latera Caldera which is an excellent test site, due to the abundant available subsurface data. Over 2500 measurements of soil CO2 flux revealed that endogenous CO2 at Latera Caldera concentrates on a NE-SW band coinciding with a structural high of fractured Mesozoic limestones hosting a water-dominated high-enthalpy geothermal reservoir. The total hydrothermal CO2 degassing from the structural high has been evaluated at 350 t d-1 from an area of 3.1 km2. It has been estimated that such a CO2 release would imply a geothermal liquid flux of 263 kg s-1, with a heat release of 239 MW. The chemical and isotopic composition of the gas indicates a provenance from the geothermal reservoir and that CO2 is partly originated by thermal metamorphic decarbonation in the hottest deepest parts of the system and partly has a likely mantle origin. The ratios of CO2, H2, CH2 and CO to Ar, were used to estimate the T-P conditions of the reservoir. Results cluster at T ~ 200-300°C and PCO2 ~ 100-200 bars, close to the actual well measurements. Finally the approach proved to be an excellent tool to investigate the presence of an active geothermal reservoir at depth and that the H2-CO2-CH4-CO-Ar gas composition is a useful T-P geochemical indicator for such CO2 rich geothermal systems

Health Hazard from Gas Emissions in the Quaternary Volcanic Province of Latium (Italy)

The Quaternary Volcanic Province of Central Italy is characterized by zones with a huge endogenous degassing where frequent, sometimes lethal, accidents occur to people and animals. The emitted gas has a deep origin (volcanic or mantle) and is mainly composed by CO2 (up to 98%) and H2S (1-4%), which may reach dangerous concentrations both in open air and indoor. Here we present the results of a multiparametric geochemical study carried out in 2007-2009 in the Provinces of Rome and Viterbo (Latium), with the aim of assessing the health hazard of their main gas emission sites (GES). Three types of GES were investigated: 1. natural, open-air thermal pools, 2. within natural reserves, 3. near to inhabited zones. More than 15 GES have been studied, and here we will illustrate some of the cases with the highest hazard. Results are presented for the sites of Vejano and Mola di Oriolo (Viterbo), Caldara di Manziana, Tor Caldara and Solforata di Pomezia (Rome). Cava dei Selci is a well-known inhabited area of the volcanic complex of Colli Albani (Rome). In each site, multi-technique surveys have been carried out to estimate the total gas output and its concentration in air, by measuring: CO2 and H2S viscous and diffuse flux (the latter by accumulation chamber), CO2 and H2S concentration in air (by TDL profiles and punctual Draeger measurements); moreover, the chemical and isotopic composition of the gas was determined in each site. In all these zones, lethal air concentrations may be reached by both H2S and CO2, but more frequently by the first. Recommendations for risk reduction were given to Civil Protection authorities.Comission of Cities and Volcanoes (CaV) of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) Agencia Española de Cooperación Internacional para el Desarrollo (AECID), Gobierno de España Ministerio de Ciencia e Innovación (MICINN), Gobierno de España Unidad Militar de Emergencias (UME), Ministerio de Defensa, Gobierno de España Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI), Gobierno de Canarias Viceconsejería de Infraestructuras y Planificación, Gobierno de Canarias Consejería de Turismo, Gobierno de Canarias Consejería de Medio Ambiente y Ordenación Territorial, Gobierno de Canarias Viceconsejería de Cultura y Deportes, Gobierno de Canarias Instituto Español de Oceanografía (IEO)Instituto Geológico y Minero de España (IGME)Instituto Geográfico Nacional (IGN)Academia Canaria de Seguridad Federación Canaria de Municipios (FECAM) Universidad de La Laguna (ULL)Instituto de Estudios Hispánicos de Canarias (IEHC) CajaCanariasPublishedPuerto de la Cruz, Tenerife, Spain1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive4.5. Studi sul degassamento naturale e sui gas petroliferiope

Soybean-and lupin-derived peptides inhibit DPP-IV activity on in situ human intestinal Caco-2 cells and ex vivo human serum

Recent investigations have focused on food-derived peptides as novel natural inhibitors of dipeptidyl peptidase IV (DPP-IV), a new target for diabetes. This study aimed to optimize fast, sensitive, and cost-effective DPP-IV assays in situ on human intestinal Caco-2 cells and ex vivo on human serum. Both assays were applied to investigate the inhibitory activity of soy and lupin peptides. The best conditions for in situ DPP-IV activity in Caco-2 cells were obtained using 2-day cells and 50 \ub5M Gly-Pro-AMC. Sitagliptin, used as reference inhibitor, showed a dose-dependent response with a 50% inhibition concentration (IC50) of 0.6 \ub5M. A lower IC50(0.2 \ub5M) was obtained for sitagliptin on human serum incubated with the substrate for 24 h. Both assays were applied to assess the activity of Lup1 (LTFPGSAED) and Soy1 (IAVPTGVA) on DPP-IV. Lup1 and Soy1 inhibited DPP-IV in situ, with IC50values of of 207.5 and 223.2 \ub5M, respectively, and maintained their inhibitory activity ex vivo on circulating DPP-IV with a slightly lower potency. These assays can be used to characterize the DPP-IV inhibitory activity of food-derived molecules more accurately than in vitro biochemical tests. This combined approach also considers their effects on the circulating form of DPP-IV, correlated to metabolic diseases

Hypocholesterolaemic Activity of Lupin Peptides : Investigation on the Crosstalk between Human Enterocytes and Hepatocytes Using a Co-Culture System Including Caco-2 and HepG2 Cells

Literature indicates that peptic and tryptic peptides derived from the enzymatic hydrolysis of lupin protein are able to modulate cholesterol metabolism in human hepatic HepG2 cells and that part of these peptides are absorbed in a small intestine model based on differentiated human Caco-2 cells. In this paper, a co-culture system, including Caco-2 and HepG2 cells, was investigated with two objectives: (a) to verify whether cholesterol metabolism in HepG2 cells was modified by the peptides absorption through Caco-2 cells; (b) to investigate how lupin peptides influence cholesterol metabolism in Caco-2 cells. The experiments showed that the absorbed peptides, not only maintained their bioactivity on HepG2 cells, but that this activity was improved by the crosstalk of the two cells systems in co-culture. In addition, lupin peptides showed a positive influence on cholesterol metabolism in Caco-2 cells, decreasing the proprotein convertase subtilisin/kexin type 9 (PCSK9) secretion

Level of carbon dioxide diffuse degassing from the ground of Vesuvio: comparison between extensive surveys and inferences on the gas source

An extensive campaign of diffuse CO2 soil flux was carried out at the cone of Vesuvio in October 2006 with two main objectives: 1) to provide an estimation of CO2 diffusely discharged through the soils in the summit area and 2) to evidence those sectors of the volcano where structural and morphological conditions could favour the gas output. The survey consisted of 502 measurements of soil CO2 flux homogenously distributed over an area of about 1.8 km2. Results of this survey were compared with those obtained during a similar campaign carried out by Frondini et al. in 2000, from which we have taken and reinterpreted a subset of data belonging to the common investigated area. Graphical statistical analysis showed three overlapping populations in both surveys, evidencing the contribution of three different sources feeding the soil CO2 degassing process. The overall CO2 emission pattern of 2006 is coherent with that observed in 2000 and suggests that a value between 120 and 140 t/day of CO2 is representative of the total CO2 discharged by diffuse degassing from the summit area of Vesuvio. The preferential exhaling area lies in the inner crater, whose contribution resulted in 45.3% of the total CO2 emission in 2006 (with 62.8 t/day) and in 57.4% (with 70.3 t/day) in 2000, although its extension is only 13% of the investigated area. This highly emissive area correlated closely with the structural discontinuities of Vesuvio cone, mainly suggesting that the NW-SE trending tectonic line is actually an active fault leaking deep gas to the bottom of the crater. The drainage action of the fault could be enhanced by the “aspiration” effect of the volcanic conduit