175 research outputs found
Temperature and pressure gas geoindicators at the Solfatara fumaroles (Campi Flegrei)
Long time series of fluid pressure and temperature within a hydrothermal
system feeding the Solfatara fumaroles are investigated here, on the basis
of the chemical equilibria within the CO2-H2O-H2-CO gas system. The
Pisciarelli fumarole external to Solfatara crater shows an annual cycle of
CO contents that indicates the occurrence of shallow secondary processes
that mask the deep signals. In contrast, the Bocca Grande and Bocca Nova
fumaroles located inside Solfatara crater do not show evidence of
secondary processes, and their compositional variations are linked to the
temperature–pressure changes within the hydrothermal system. The
agreement between geochemical signals and the ground movements of the
area (bradyseismic phenomena) suggests a direct relationship between the
pressurization process and the ground uplift. Since 2007, the gas
geoindicators have indicated pressurization of the system, which is most
probably caused by the arrival of deep gases with high CO2 contents in
the shallow parts of the hydrothermal system. This pressurization process
causes critical conditions in the hydrothermal system, as highlighted by
the increase in the fumarole temperature, the opening of new vents, and
the localized seismic activity. If the pressurization process continues with
time, it is not possible to rule out the occurrence of phreatic explosions
Long time-series of chemical and isotopic compositions of Vesuvius fumaroles: evidence for deep and shallow processes
Long time-series of chemical and isotopic compositions of Vesuvius
fumaroles were acquired in the framework of the volcanic surveillance in
the 1998-2010 period. These allow the identification of processes that
occur at shallow levels in the hydrothermal system, and variations that are
induced by deep changes in volcanic activity. Partial condensation
processes of fumarolic water under near-discharge conditions can explain
the annual 18O and deuterium variabilities that are observed at Vesuvius
fumaroles. Significant variations in the chemical compositions of
fumaroles occurred over the 1999-2002 period, which accompanied the
seismic crisis of autumn 1999, when Vesuvius was affected by the most
energetic earthquakes of its last quiescence period. A continuous increase
in the relative concentrations of CO2 and He and a general decrease in the
CH4 concentrations are interpreted as the consequence of an increment in
the relative amount of magmatic fluids in the hydrothermal system. Gas
equilibria support this hypothesis, showing a PCO2 peak that culminated in
2002, increasing from values of ~40 bar in 1998 to ~55-60 bar in 2001-
2002. We propose that the seismic crisis of 1999 marked the arrival of the
magmatic fluids into the hydrothermal system, which caused the observed
geochemical variations that started in 1999 and culminated in 2002
Thermal monitoring of hydrothermal activity by permanent infrared automatic stations: Results obtained at Solfatara di Pozzuoli, Campi Flegrei (Italy)
A permanent automatic infrared (IR) station was installed at Solfatara crater, the most active zone of Campi Flegrei caldera. After a positive in situ calibration of the IR camera, we analyze 2175 thermal IR images of the same scene from 2004 to 2007. The scene includes a portion of the steam heated hot soils of Solfatara. The experiment was initiated to detect and quantify temperature changes of the shallow thermal structure of a quiescent volcano such as Solfatara over long periods. Ambient temperature results as the main parameter affecting IR temperatures while air humidity and rain control image quality. A geometric correction of the images was necessary to remove the effects of slow movement of the camera. After a suitable correction the images give a reliable and detailed picture of the temperature changes, over the period October 2004 – January 2007, which suggests origin of the changes were linked to anthropogenic activity, vegetation growth and to the increase of the flux of hydrothermal fluids in the area of the hottest fumaroles. Two positive temperature anomalies were registered after the occurrence of two seismic swarms which affected the hydrothermal system of Solfatara in October 2005 and October 2006. It is worth noting that these signs were detected in a system characterized by a low level of activity with respect to systems affected by real volcanic crisis where more spectacular results will be expected. Results of the experiment show that this kind of monitoring system can be a suitable tool for volcanic surveillance
Long Time Series Of Fumarolic Compositions At Volcanoes: The Key To Understand The Activity Of Quiescent Volcanoes
Long time series of fumarolic chemical and isotopic
compositions at Campi Flegrei, Vulcano, Panarea,
Nisyros and Mammoth volcanoes highlight the occurrence
of mixing processes among magmatic and hydrothermal
fluids. At Campi Flegrei temperatures of
about 360°C of the hydrothermal system are inferred by
chemical and isotopic geoindicators. These high temperatures
are representative of a deep zone where magmatic
gases mix with hydrothermal liquids forming the gas plume feeding the fumaroles. Similar mixing processes
between magmatic fluids and a hydrothermal
component of marine origin have been recognized at
Vulcano high temperature fumaroles. In both the system
a typical ‘andesitic’ water type composition and high
CO2 contents characterizes the magmatic component.
Our hypothesis is that pulsing injections of these CO2-
rich magmatic fluids at the bottom of the hydrothermal
systems trigger the bradyseismic crises, periodically
affecting Campi Flegrei, and the periodical volcanic
unrest periods of Vulcano. At Campi Flegrei a strong
increase of the fraction of the magmatic component
marked the bradyseismic crisis (seismicity and ground
uplift) of 1982-84 and four minor episodes occurred in
1989, 1994 and 2000 and 2006. Increases of the magmatic
component in the fumaroles of Vulcano were recorded
in 1979-1981, 1985, 1988, 1996, 2004 and 2005
concurrently with anomalous seismic activity. Physicalnumerical
simulations of the injection of hot, CO2 rich
fluids at the base of a hydrothermal system, asses the
physical feasibility the process. Ground deformations,
gravitational anomalies and seismic crisis can be well
explained by the complex fluid dynamic processes
caused by magma degassing episodes. Sporadic data
on the fumaroles of other volcanoes, for example Panarea,
Nisyros (Greece), Mammoth (California), suggest
that magma degassing episodes frequently occur in
dormant volcanoes causing volcanic unrest processes
not necessarily linked to magma movement but rather
to pulsating degassing processes from deep pressurized,
possibly stationary, magma bodies
Therapeutic Strategies Targeting Urokinase and Its Receptor in Cancer
Several studies have ascertained that uPA and uPAR do participate in tumor progression and metastasis and are involved in cell adhesion, migration, invasion and survival, as well as angiogenesis. Increased levels of uPA and uPAR in tumor tissues, stroma and biological fluids correlate with adverse clinic–pathologic features and poor patient outcomes. After binding to uPAR, uPA activates plasminogen to plasmin, a broad-spectrum matrix-and fibrin-degrading enzyme able to facilitate tumor cell invasion and dissemination to distant sites. Moreover, uPAR activated by uPA regulates most cancer cell activities by interacting with a broad range of cell membrane receptors. These findings make uPA and uPAR not only promising diagnostic and prognostic markers but also attractive targets for developing anticancer therapies. In this review, we debate the uPA/uPAR structure–function relationship as well as give an update on the molecules that interfere with or inhibit uPA/uPAR functions. Additionally, the possible clinical development of these compounds is discussed
. New ground-based lidar enables volcanic CO2 flux measurements
There have been substantial advances in the ability to monitor the activity of hazardous volcanoes
in recent decades. However, obtaining early warning of eruptions remains challenging, because the
patterns and consequences of volcanic unrests are both complex and nonlinear. Measuring volcanic
gases has long been a key aspect of volcano monitoring since these mobile fluids should reach the
surface long before the magma. There has been considerable progress in methods for remote and
in-situ gas sensing, but measuring the flux of volcanic CO2—the most reliable gas precursor to an
eruption—has remained a challenge. Here we report on the first direct quantitative measurements
of the volcanic CO2 flux using a newly designed differential absorption lidar (DIAL), which were
performed at the restless Campi Flegrei volcano. We show that DIAL makes it possible to remotely
obtain volcanic CO2 flux time series with a high temporal resolution (tens of minutes) and accuracy
(<30%). The ability of this lidar to remotely sense volcanic CO2 represents a major step forward
in volcano monitoring, and will contribute improved volcanic CO2 flux inventories. Our results also
demonstrate the unusually strong degassing behavior of Campi Flegrei fumaroles in the current
ongoing state of unrest
Geochemical and biochemical evidence of lake overturn and fish-kill at Lake Averno, Italy.
Lake Averno is situated in the homonymous crater in the northwestern sector of the Campi Flegrei active
volcanic system in Campania region, Italy. In February 2005 a fish kill event was observed in the lake,
prompting a geochemical survey to ascertain the possible cause. In February 2005 a geochemical survey
revealed that the lake water was unstratified chemically and isotopically, presumable, as a result of lake
overturn. This fish-kill phenomenon was recorded at least two other times in the past. In contrast to the
February 2005 results, data collected in October 2005, shows the Lake Averno to be stratified, with an oxic
epilimnion (surface to 6 m) and an anoxic hypolimnion (6 m to lake bottom at about 33 m).
Chemical and isotopic composition of Lake Averno waters suggests an origin by mixing of shallow waters
with a Na-Cl hydrothermal component coupled with an active evaporation process. The isotopic composition
of Dissolved Inorganic Carbon, as well as the composition of the non-reactive dissolved gas species again
supports the occurrence of this mixing process.
Decreasing levels of SO4 and increasing levels of H2S and CH4 contents in lake water with depth, strongly
suggests anaerobic bacterial processes are occurring through decomposition of organic matter under anoxic
conditions in the sediment and in the water column. Sulfate reduction and methanogenesis processes coexist
and play a pivotal role in the anaerobic environment of the Lake Averno. The sulfate reducing bacterial
activity has been estimated in the range of 14-22 μmol.m-2.day-1.
Total gas pressure of dissolved gases ranges between 800 and 1400 mbar, well below the hydrostatic
pressure throughout the water column, excluding the possibility, at least at the survey time, of a limnic
eruption.
Vertical changes in the density of lake waters indicate that overturn may be triggered by cooling of
epilimnetic waters below 7°C. This is a possible phenomenon in winter periods if atmospheric temperatures
remain frosty for enough time, as occurred in February 2005.
The bulk of these results strongly support the hypothesis that fish kill was caused by a series of events that
began with the cooling of the epilimnetic waters with breaking of the thermal stratification, followed by lake
overturn and the rise of toxic levels of H2S from the reduced waters near the lake bottom
Improving monitoring techniques by exploiting TerraSAR-X data: an application to Campi Flegrei (Naples, Italy)
Geodetic monitoring of the Neapolitan Volcanic District, including the Campi Flegrei caldera on the west of the
city of Naples (Italy), is carried out via an integration between ground based networks and space-borne DInSAR
techniques, exploiting the SAR sensors onboard ERS1-2 and ENVISAT satellites. This allowed, for instance, to
follow the time evolution of the small uplift events which took place in 2000 and 2005-2006. Unfortunately, the
use of the ENVISAT C-band could result sometimes in no information when dealing with very low deformation
rates, as in the 2005-2006 case, when only continuous ground stations were able to detect the very beginning of
the uplift event.
To overcome this problem, from December 2009 we decided to use an high resolution SAR sensor operating in
the X band, i.e. TerraSAR-X from DLR.
TerraSAR-X High Resolution Spotlight scenes covering the main part of the Campi Flegrei caldera and centred on
the Solfatara crater were used for a DInSAR analysis, using the GENESIS DLR’s software. The first two scenes
(Dec. 15 and 26) were acquired with a temporal baseline of only one repetition cycle (11 days) and formed an
interferogram with a very small perpendicular baseline (16.5 m).
Apart from some minor atmospheric effects, the interferogram shows a small but clear deformation signal in the
Pisciarelli area, close to the east side of the Solfatara crater. The ellipse shaped uplift area extends approximately
30 meters in E-W and 20 meters in N-S directions and the maximum deformation is up to 10 mm in the centre of
the uplifted area.
The availability of a new scene (06/01/2010) allowed three possible combinations.
The deformation event highlighted by this analysis is consistent with geochemical observations carried out in
Pisciarelli by INGV-OV.
Pisciarelli area is seat of a fumarolic field systematically monitored in the frame of the volcanic surveillance of
the Campi Flegrei caldera. Two field surveys highlighted that, during the period of SAR images acquisition, a
new and strong fumarolic vent appeared in the centre of the uplifted area. In fact the vent, firstly observed on
Dec. 21, was absent on Dec. 16. The two independent observations, field surveys and SAR data, suggest that the
opening of the fumarolic vent was preceded by the pressurization of a small part of the fumarolic field highlighted
by the documented uplift. The correlation between the dynamics of the fumarolic field and the deformation
signal is confirmed by the fact that in the 26/12/2009-06/01/2010 interferogram the deformation signal is no more
detectable.
Finally, this case proves the high potentiality of TerraSAR-X High Resolution Spotlight data in monitoring
volcanic activity with a resolution suitable for detecting also minor, but possibly dangerous, changes of the
systems, as it could be in the early recognition of the signals generated by impending phreatic eruptions.
TerraSAR-X High Resolution Spotlight acquisitions will continue every cycle and PS-InSAR and SBAS algorithms
will be applied to carefully monitor any further changes in the activity of the Campi Flegrei volcanic system
One year of geochemical monitoring of groundwater in the Abruzzi region after the 2009 earthquakes.
The presence of a deep and inorganic source of CO2 has been recently recognized in Italy on the basis of the
deeply derived carbon dissolved in the groundwater. In particular, the regional map of CO2 Earth degassing
shows that two large degassing structures (Tuscan Roman degassing structure, TRDS, and Campanian degassing
structure, CDS) affect the Tyrrhenian side of the Italian peninsula. The comparison between the map of CO2
Earth degassing and of the location of the Italian earthquakes highlights that the anomalous CO2 flux suddenly
disappears in the Apennine in correspondence of a narrow band where most of the seismicity concentrates. A
previous conceptual model proposed that in this area, at the eastern borders of TRDS and CDS, the CO2 from the
mantle wedge intrudes the crust and accumulate in structural traps generating over-pressurized reservoirs. These
CO2 over-pressurized levels can play a major role in triggering the Apennine earthquakes.
The 2009 Abruzzo earthquakes, like previous seismic crises in the Northern Apennine, occurred at the border of
the TRDS, suggesting also in this case a possible role played by deeply derived fluids in the earthquake generation.
Detailed hydro-geochemical campaigns, with a monthly frequency, started immediately after the main shock of
the 6th of April 2009. The new campaigns include the main springs of the area which were previously studied in
detail, during a campaign performed ten years ago, constituting a pre-crisis reference case. Almost one year of
geochemical data of the main dissolved ions, of dissolved gases (CO2, CH4, N2, Ar, He) and of the stable isotopes
of the water (H, O), CO2 (13C) and He (3He/4He), highlight both that the epicentral area of L’Aquila earthquakes
is affected by an important process of CO2 Earth degassing and that that the gases dissolved in the groundwater
reflects the input in to the aquifers of a deep gas phase, CO2- rich, with an high He content and with low 3He/4He
ratios, similar to the gases emitted by natural manifestations located in the northern Apennines which are fed by
deep pressurized reservoirs. Furthermore a systematic increase in the content of the deeply derived CO2 dissolved
in the aquifers occurred respect to the July 1997 samples. This increase, followed by a gentle decline of the
anomaly, can be compatible with the occurrence of an episode of deep CO2 degassing concurrently with the earthquakes.
The origin of this regional variation is under investigation and, at the present moment, an unambiguous
interpretation of the data is not possible because the lack of a systematic monitoring of the springs before the
seismic events and because eventual seasonal effects on observed variation in CO2 flux are still under investigatio
Colorimetric Test for Fast Detection of SARS-CoV-2 in Nasal and Throat Swabs
Mass testing is fundamental to face the pandemic caused by the coronavirus SARS-CoV-2 discovered at the end of 2019. To this aim, it is necessary to establish reliable, fast, and cheap tools to detect viral particles in biological material so to identify the people capable of spreading the infection. We demonstrate that a colorimetric biosensor based on gold nanoparticle (AuNP) interaction induced by SARS-CoV-2 lends itself as an outstanding tool for detecting viral particles in nasal and throat swabs. The extinction spectrum of a colloidal solution of multiple viral-target gold nanoparticles-AuNPs functionalized with antibodies targeting three surface proteins of SARS-CoV-2 (spike, envelope, and membrane)-is red-shifted in few minutes when mixed with a solution containing the viral particle. The optical density of the mixed solution measured at 560 nm was compared to the threshold cycle (Ct) of a real-time PCR (gold standard for detecting the presence of viruses) finding that the colorimetric method is able to detect very low viral load with a detection limit approaching that of the real-time PCR. Since the method is sensitive to the infecting viral particle rather than to its RNA, the achievements reported here open a new perspective not only in the context of the current and possible future pandemics, but also in microbiology, as the biosensor proves itself to be a powerful though simple tool for measuring the viral particle concentration
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