64 research outputs found

    Active alkaline traps to determine acidic-gas ratios in volcanic plumes: Sampling techniques and analytical methods

    Get PDF
    In situ measurements have been the basis for monitoring volcanic gas emissions for many years and—being complemented by remote sensing techniques—still play an important role to date. Con- cerning in situ techniques for sampling a dilute plume, an increase in accuracy and a reduction of detection limits are still necessary for most gases (e.g., CO2, SO2, HCl, HF, HBr, HI). In this work, the Raschig-Tube tech- nique (RT) is modified and utilized for application on volcanic plumes. The theoretical and experimental absorption properties of the RT and the Drechsel bottle (DB) setups are characterized and both are applied simultaneously to the well-established Filter packs technique (FP) in the field (on Stromboli Island and Mount Etna). The comparison points out that FPs are the most practical to apply but the results are error- prone compared to RT and DB, whereas the RT results in up to 13 times higher analyte concentrations than the DB in the same sampling time. An optimization of the analytical procedure, including sample pretreat- ment and analysis by titration, Ion Chromatography, and Inductively Coupled Plasma Mass Spectrometry, led to a comprehensive data set covering a wide range of compounds. In particular, less abundant species were quantified more accurately and iodine was detected for the first time in Stromboli's plume. Simultane- ously applying Multiaxis Differential Optical Absorption Spectroscopy (MAX-DOAS) the chemical transforma- tion of emitted bromide into bromine monoxide (BrO) from Stromboli and Etna was determined to 3–6% and 7%, respectively, within less than 5 min after the gas release from the active vents

    CO2 Degassing in Sicily (Central Mediterranean) as Inferred from Groundwater Composition

    Get PDF
    The circulation of groundwater is influenced by several factors, including permeability changes due to the dynamics of the stress field acting along tectonic discontinuities. Open faults can act as preferential pathways for the escape of crustal and subcrustal gases, such as CO2, towards the surface, allowing their chemical interaction with meteoric fluids. Here, we present the first map of dissolved CO2 partial pressure in the groundwater of Sicily, Italy. Based on the chemical analysis of 557 samples of groundwater, which were collected in wells and springs, we calculated the related CO2 partial pressure (PCO2) using PHREEQC software. The spatial distribution of the calculated PCO2 values highlights a general homogeneity at the regional scale, interrupted by positive anomalies linked to the main seismogenic or volcanic areas. Faults work as preferential escape pathways for deep CO2. The subsequent CO2–water–rock interaction determines the chemical composition of circulating water. As a consequence, groundwater composition can be successfully used to identify anomalous degassing areas

    Plume composition and volatile flux of Nyamulagira volcano, Democratic Republic of Congo, during birth and evolution of the lava lake, 2014–2015

    Get PDF
    Very little is known about the volatile element makeup of the gaseous emissions of Nyamulagira volcano. This paper tries to fill this gap by reporting the first gas composition measurements of Nyamulagira’s volcanic plume since the onset of its lava lake activity at the end of 2014. Two field surveys were carried out on 1 November 2014, and 13–15 October 2015. We applied a broad toolbox of volcanic gas composition measurement techniques in order to geochemically characterize Nyamulagira’s plume. Nyamulagira is a significant emitter of SO2, and our measurements confirm this, as we recorded SO2 emissions of up to ~ 14 kt/d during the studied period. In contrast to neighbouring Nyiragongo volcano, however, Nyamulagira exhibits relatively low CO2/SO2 molar ratios ( 92%of total gas emissions). Strong variations in the volatile composition, in particular for the CO2/SO2 ratio, were measured between 2014 and 2015, which appear to reflect the simultaneous variations in volcanic activity.We also determined the molar ratios for Cl/S, F/S and Br/S in the plume gas, finding values of 0.13 and 0.17, 0.06 and 0.11, and 2.3·10−4 and 1·10−4, in 2014 and 2015, respectively. A total gas emission flux of 48 kt/ d was estimated for 2014. The I/S ratio in 2015 was found to be 3.6·10−6. In addition, we were able to distinguish between hydrogen halides and non-hydrogen halides in the volcanic plume. Considerable amounts of bromine (18–35% of total bromine) and iodine (8–18%of total iodine) were found in compounds other than hydrogen halides. However, only a negligible fraction of chlorine was found as compounds other than hydrogen chloride.Published905V. Dinamica dei processi eruttivi e post-eruttiviJCR Journa

    Isotopic composition of the precipitations in the central Mediterranean: Origin marks and orographic precipitation effects

    Get PDF
    The isotopic composition of the rainfall in northwestern Sicily (Italy, central Mediterranean) was investigated in the period February 2002 to March 2003. A rain gauge network was installed and sampled monthly. The monthly values of the D and 18O ratios showed a wide range that reflected seasonal climatic variations. Mean weighted values were used to define an isotopic model of precipitation. Temporal variations in deuterium excess were also investigated. Using mean volume weighted values, the Local Meteoric Water Line (LMWL) can be represented by the equation: \u3b4D = 4.7\u3b418O - 8.2 (r2 = 0.96). Deuterium excess (d = \u3b4D - 8\u3b418O) was found to be strongly related to orography. The coastline samples were characterized by mean weighted deuterium excess values close to 12.5\u2030 samples from inland areas showed values of 169\u2030, while samples taken from the main reliefs showed values close to 19%\ub7 In inland areas, isotopic exchange between raindrops and moisture could shift the deuterium excess values slightly. On the higher reliefs, the interaction between falling raindrops and orographic clouds could shift the deuterium excess values significantly. The low slope of the LMWL could be referred to the high deuterium excess values of the higher sites and is related to orographic precipitation rather than to evaporation processes during the fall of the raindrops. The results obtained suggest that local orographic features may significantly change the isotopic composition of precipitation. Copyright 2006 by the American Geophysical Union

    Functional Differences in Visceral and Subcutaneous Fat Pads Originate from Differences in the Adipose Stem Cell

    Get PDF
    Metabolic pathologies mainly originate from adipose tissue (AT) dysfunctions. AT differences are associated with fat-depot anatomic distribution in subcutaneous (SAT) and visceral omental (VAT) pads. We address the question whether the functional differences between the two compartments may be present early in the adipose stem cell (ASC) instead of being restricted to the mature adipocytes. Using a specific human ASC model, we evaluated proliferation/differentiation of ASC from abdominal SAT-(S-ASC) and VAT-(V-ASC) paired biopsies in parallel as well as the electrophysiological properties and functional activity of ASC and their in vitro-derived adipocytes. A dramatic difference in proliferation and adipogenic potential was observed between the two ASC populations, S-ASC having a growth rate and adipogenic potential significantly higher than V-ASC and giving rise to more functional and better organized adipocytes. To our knowledge, this is the first comprehensive electrophysiological analysis of ASC and derived-adipocytes, showing electrophysiological properties, such as membrane potential, capacitance and K+-current parameters which confirm the better functionality of S-ASC and their derived adipocytes. We document the greater ability of S-ASC-derived adipocytes to secrete adiponectin and their reduced susceptibility to lipolysis. These features may account for the metabolic differences observed between the SAT and VAT. Our findings suggest that VAT and SAT functional differences originate at the level of the adult ASC which maintains a memory of its fat pad of origin. Such stem cell differences may account for differential adipose depot susceptibility to the development of metabolic dysfunction and may represent a suitable target for specific therapeutic approaches

    Models for preclinical studies in aging-related disorders: one is not for all

    Get PDF
    Preclinical studies are essentially based on animal models of a particular disease. The primary purpose of preclinical efficacy studies is to support generalization of treatment–effect relationships to human subjects. Researchers aim to demonstrate a causal relationship between an investigational agent and a disease-related phenotype in such models. Numerous factors can muddle reliable inferences about such causeeffect relationships, including biased outcome assessment due to experimenter expectations. For instance, responses in a particular inbred mouse might be specific to the strain, limiting generalizability. Selecting well-justified and widely acknowledged model systems represents the best start in designing preclinical studies, especially to overcome any potential bias related to the model itself. This is particularly true in the research that focuses on aging, which carries unique challenges, mainly attributable to the fact that our already long lifespan makes designing experiments that use people as subjectsextremely difficult and largely impractical

    Prevention of food and airway allergy: consensus of the Italian Society of Preventive and Social Paediatrics, the Italian Society of Paediatric Allergy and Immunology, and Italian Society of Pediatrics

    Get PDF

    The reference site collaborative network of the european innovation partnership on active and healthy ageing

    Get PDF
    Seventy four Reference Sites of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA) have been recognised by the European Commission in 2016 for their commitment to excellence in investing and scaling up innovative solutions for active and healthy ageing. The Reference Site Collaborative Network (RSCN) brings together the EIP on AHA Reference Sites awarded by the European Commission, and Candidate Reference Sites into a single forum. The overarching goals are to promote cooperation, share and transfer good practice and solutions in the development and scaling up of health and care strategies, policies and service delivery models, while at the same time supporting the action groups in their work. The RSCN aspires to be recognized by the EU Commission as the principal forum and authority representing all EIP on AHA Reference Sites. The RSCN will contribute to achieve the goals of the EIP on AHA by improving health and care outcomes for citizens across Europe, and the development of sustainable economic growth and the creation of jobs

    Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)

    Get PDF
    The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer‐reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state‐of‐the‐art handbook for basic and clinical researchers.DFG, 389687267, Kompartimentalisierung, Aufrechterhaltung und Reaktivierung humaner Gedächtnis-T-Lymphozyten aus Knochenmark und peripherem BlutDFG, 80750187, SFB 841: Leberentzündungen: Infektion, Immunregulation und KonsequenzenEC/H2020/800924/EU/International Cancer Research Fellowships - 2/iCARE-2DFG, 252623821, Die Rolle von follikulären T-Helferzellen in T-Helferzell-Differenzierung, Funktion und PlastizitätDFG, 390873048, EXC 2151: ImmunoSensation2 - the immune sensory syste
    corecore