103,012 research outputs found
Le Fumarole di Vulcano
No full textIn tempi storici l’Isola di Vulcano è stata interessata da numerose eruzioni. Come già detto l’ultima
attività vulcanica è avvenuta fra il 1888 e il 1890. Da allora l’attività del vulcano è caratterizzata dalla presenza di numerose aree fumarolizzate...Published65 - 733.5. Geologia e storia dei vulcani ed evoluzione dei magmiope
Aeromagnetic data provide new insights on the volcanism and tectonics of Vulcano Island and offshore areas (southern Tyrrhenian Sea, Italy)
No full textThe active Vulcano Island (Southern Tyrrhenian Sea)
represents the southernmost portion of a NW-SE elongated
volcanic ridge that includes also Lipari and Salina islands.
The ridge is affected by a regional, NW-SE to N-S striking
fault system. The elaboration and analysis of data from
three high-resolution aeromagnetic surveys carried out
between 1999 and 2004 on Vulcano and offshore allow us
to recognize high intensity magnetic anomalies related to
volcanic centers/conduits or shallow intrusions. Previously
unreported offshore submarine vents have been also
recognized. Some of them may correspond with source
areas of outcropping exotic pyroclastics on Vulcano. The
spatial analysis of the recognized magnetic anomalies and
volcanic structures shows that they are preferably aligned
along the strikes of the main regional faults that affect the
volcanic ridge. Submarine volcanic conduits revealed by
the aeromagnetic survey might represent potential sources
for future submarine, effusive or explosive activity.PublishedL153053.8. Geofisica per l'ambienteJCR Journalreserve
Tilt measurements at Vulcano Island
No full textA network of tiltmeters has been operational on Vulcano Island for numerous years. At present, the network comprises five functioning borehole stations, four of which are installed at 8-10 m and allow recording very stable, high precision signals with very low noise.
We report observations over the last 12 years that illustrate impulsive variations linked to seismicity and long-term (several years) trends in the signals. We suggest a relationship between tilt changes correlated to the strongest regional seismic events and site acceleration; long-term tilt variations analyzed in combination with other ground deformation data seem to represent the evidence of a contraction of the La Fossa cone.
We also analyzed how the tilt device has the capability to detect possible magma migrations; we considered previous studies that have imaged spatially well-defined levels of magma accumulation beneath La Fossa, and Vulcanello; we concluded that the Vulcano tilt network should be capable of detecting the upward migration of small magma volumes.
Finally, we show that no evidence of changes are visible on tilt signals during anomalous degassing episodes (linked to a building up input of magmatic fluids) at the La Fossa thereby evidencing that no magma migration occurred during such events.Published233-2471.3. TTC - Sorveglianza geodetica delle aree vulcaniche attiveJCR Journalope
Transmission of human immunodeficiency virus (HIV)
No full textThe present contribution is a Letter to the Editor (Correspondence). Therefore, no abstract is available.[...
Structural features of the shallow plumbing system of Vulcano Island Italy
No full textAbstract In this study, we integrate information gathered
from surface geology and tectonics with the results of a
shallow (0–2 km b.s.l.) seismic tomography of Vulcano
Island (Italy), obtained from the analysis of local
earthquakes. The observed low Vp regions correspond
to caldera filling products, mainly consisting of pyroclastics,
tuffs, lava flows and hyaloclastites. High-velocity
anomalies represent intrusive bodies. The striking correspondence
between the stratigraphy from deep wells and
the calculated velocity structure allows us to reconstruct
the geometry and distribution of a main intrusion and to
recognize some intra-caldera depressions. The shape and
location of the high and low Vp anomalies are consistent
with NW–SE and N–S strikes. Eruptive centres younger
than 42 kyr, as well as the structural depressions of
Vulcano and of the neighbour Lipari Island, align along a
N–S direction. The combined interpretation of the
available structural data and of the results from the
tomography suggests that magmatic reservoirs of Vulcano
at shallow depth (>0.5 km) align along a NW–SE strike
but their shape is controlled by N–S striking normal faults
and/or cracks that accommodate the right-lateral movements
of the NW–SE strike-slip fault system.Publishedreserve
Geologia - Inquadramento Geologico e Storia Eruttiva
No full textIn the framework of the Aeolian Volcanic District evolution, the chapter provides the reconstruction of the Vulcano Island history through the subdivision in eight Eruptive Epochs.Published33-473.5. Geologia e storia dei vulcani ed evoluzione dei magmiope
Geologia - Inquadramento Geologico e Storia Eruttiva
No full textIn the framework of the Aeolian Volcanic District evolution, the chapter provides the reconstruction of the Vulcano Island history through the subdivision in eight Eruptive Epochs.Published33-473.5. Geologia e storia dei vulcani ed evoluzione dei magmiope
Successione vulcano-sedimentaria triassica
No full textSuccessione vulcano-sedimentaria triassica delle Alpi Meridionali
Towards the design of improved g-glutamyltransferase as biocatalyst for nutraceuticals and food additives
No full textGamma-Glutamyl peptides are compounds deriving from the acylation of an amino acid by the gamma-carboxyl carbon of L-glutamic acid. Gamma-Glutamylation of amino acids affects some chemical-physical as well as organoleptic properties of the parent molecule. Some naturally occurring gamma-glutamyl derivatives show pharmacological activity or represent taste-active compounds with flavor-enhancing capacities.
Enzymatic approaches based on the use of -glutamyltransferases (GGT, E.C. 2.3.2.2) for the preparation of gamma-glutamyl derivatives have been proposed over time. They circumvent the drawbacks of chemical synthesis, which is cumbersome and uneconomical due to the requirement for multiple protection-deprotection steps on the interfering functionalities of the reacting molecules. Bacterial GGTs appears to be convenient biocatalysts, able to use the cheap and readily available glutamine as the gamma-glutamyl donor compound
We report preliminary results obtained with two bacterial GGTs with different architectures of the active site for the synthesis of gamma-glutamyl derivatives of S-substituted cysteines, which are naturally occurring flavor enhancers found in plant of the genus Allium.
The effects of pH, temperature and substrates molar ratio were examined in reactions catalyzed by both enzymes and will be discussed in the light of the structural differences between the two biocatalysts.
This work represents a first, unprecedented study in which two bacterial GGTs of different origins are directly compared and in which the attitude of the enzymes to function as biocatalysts is related to their structural characteristics. This approach could be useful for the design of mutant enzymes better suited for preparative purposes
Data for the synthesis of oligo-gamma-glutamylglutamines as model compounds for gamma-glutamyltransferases (GGTs) and for normalization of activities of different GGTs
No full textgamma-Glutamyltransferases (GGTs) are widespread, conserved enzymes that catalyze the transfer of the gamma-glutamyl moiety from a donor substrate to water (hydrolysis) or to an acceptor amino acid (transpeptidation) through the formation of a gamma-glutamyl enzyme intermediate.
Although the vast majority of the known GGTs has a short sequence called lid-loop covering the glutamate binding site, B. subtilis GGT and some other enzymes from Bacillus spp. lack the lid loop. In order to assess the possible role of the lid loop of GGTs in substrate selection, synthetic oligo-gamma-glutamylglutamines containing up to three gamma-glutamyl residues were used as model substrates. The activities of the enzymes under investigation were standardized with respect to a common reaction to ensure comparable results. The activity of an engineered mutant enzyme containing the amino acid sequence of the lid loop from E. coli GGT inserted into the backbone of B. subtilis GGT was compared to that of the lid loop-deficient B. subtilis GGT and the lid loop-carrier E. coli GGT (Calvio, Romagnuolo, Vulcano, Speranza, Morelli Enz. Micr. Technol. 2018 [1]). Here we report the experimental procedures for the synthesis of model substrates gamma-glutamylglutamines through the method of the N-phtaloyl-L-glutamic acid anhydride and the spectral data of the synthetized compounds. The data obtained in the normalization procedure of the activities of the three enzymes are also reported
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