An oceanographic cruise campaign on-board the Italian research vessel Urania was carried out from the 26th of August to the 13th of September 2010 in the Eastern Mediterranean. The campaign sought to ...investigate the mercury cycle at coastal and offshore locations in different weather conditions. The experimental activity focused on measuring mercury speciation in both seawater and in air, and using meteorological parameters to estimate elemental mercury exchange at the sea–atmosphere interface. Dissolved gaseous mercury (DGM), unfiltered total mercury (UTHg) and filtered total mercury (FTHg) surface concentrations ranged from 16 to 114, 300 to 18,760, and 230 to 10,990pgL−1, respectively. The highest DGM, UTHg and FTHg values were observed close to Augusta (Sicily), a highly industrialized area of the Mediterranean region, while the lowest values were recorded at offshore stations. DGM vertical profiles partially followed the distribution of sunlight, as a result of the photoinduced transformations of elemental mercury in the surface layers of the water column. However, at some stations, we observed higher DGM concentrations in samples taken from the bottom of the water column, suggesting biological mercury production processes or the presence of tectonic activity. Moreover, two days of continuous measurement at one location demonstrated that surface DGM concentration is affected by solar radiation and atmospheric turbulence intensity. Atmospheric measurements of gaseous elemental mercury (GEM) showed an average concentration (1.6ngm−3) close to the background level for the northern hemisphere. For the first time this study used a numerical scheme based on a two-thin film model with a specific parameterization for mercury to estimate elemental mercury flux. The calculated average mercury flux during the entire cruise was 2.2±1.5ngm−2h−1. The analysis of flux data highlights the importance of the wind speed on the mercury evasion from sea surfaces.
► The Hg cycle in the East Mediterranean Marine Boundary Layer was examined. ► Sunlight, wind and CDOM influenced dissolved gaseous mercury. ► Anthropogenic influences on concentrations and fluxes were found to be important.
Objective
To evaluate whether apparent diffusion coefficient (ADC) values can predict the status of MGMT of glioblastoma multiforme (GBM) and correlate with overall survival (OS) and progression-free ...survival (PFS).
Methods
This retrospective study included 47 patients with pathologically proven glioblastoma. All of them underwent MR DWI study before surgery (mean time 1 week) and the status of methylguanine-DNA-methyltransferase (MGMT) promoter methylation was searched for. Minimum apparent diffusion coefficient (ADC) values were evaluated. OS and PSF parameters were calculated, and Student’s t-test, Kaplan-Meier curves, linear and Cox regression were performed.
Results
Twenty-five patients showed positive methylation of the MGMT promoter. Patients showing MGMT promoter methylation had higher minimum ADC values, and they survived longer than those without MGMT promoter methylation. The median ADCmin value of 0.80 represents the cutoff value able to distinguish between methylated and un-methylated patients. Patients showing minimum ADC values higher than 0.80 survived longer than patients with minimum ADC values lower than 0.80. A linear correlation between minimum ADC values vs. the OS and PFS was observed.
Conclusions
Minimum ADC values in glioblastoma multiforme could be used as a preoperative parameter to estimate the status of MGMT promoter methylation and the survival of patients.
Key Points
• Diffusion-weighted MR imaging (DWI) provides new insights into glioblastoma multiforme (GBM)
• DWI ADCmin values can predict the methylation status of MGMT promoter.
• The MGMT promoter methylation group survived longer than the unmethylated group.
• Patients with high ADCmin values survived longer than patients with low values.
The purposes of this study were (1) to evaluate the possible identification of trajectories of fibre tracts, (2) to examine the useful of a neuronavigation system for pre-surgical planning, (3) to ...assess pre- and post-surgery patients’ clinical condition and (4) to evaluate the impact of this information on surgical planning and procedure. Twenty-eight right-handed patients were prospectively and consecutively studied. All the patients were clinically assessed by a neurologist in both pre- and post-surgical phases. Separately the pyramidal tract, optic radiation and arcuate fasciculus were reconstructed. The trajectories were considered suitable for surgical planning if there were no interruptions of any of the layers at the level of the lesion. Dedicated software ‘merged’ the acquired images with the tractographic processing, and the whole dataset was sent to the neuronavigation system. The assessment of the 37 visualised trajectories close to the tumour resulted in a modification of the surgical approach to corticotomy in six patients (21%); the impact on the definition of the resection margins during surgery was 64% (18 cases). The overall impact percentage on the surgical procedure was 82%. In 27 cases, the symptoms had not changed. MR-tractography provides the neurosurgeon with a new anatomical view that has an impact on the surgical resection planning for brain neoplasms.
The aim of the study was to evaluate the airborne contamination by polycyclic aromatic hydrocarbons (PAHs) and some heavy metals (arsenic As, cadmium Cd, chromium Cr, copper Cu, nickel Ni, lead Pb, ...and zinc Zn) of different pollution scenarios around a solid-waste landfill in central Italy using the lichen Pseudovernia furfuracea as a monitoring tool. For this purpose, eight stations around a landfill characterized by different air pollution sources (industrial, agricultural, residential areas, and roads with different traffic intensities), together with three stations far from the landfill (control areas), were monitored using a set of 22 lichen samples (11 samples analysed for PAHs and metals after 4 months, and 11 samples analysed for metals after 8 months). After 4 months of exposure, the lichen content of all of the analysed elements was greater than that in the pre-exposed lichens. In addition, the Cu and Pb concentration after 8 months was greater than the level after 4 months. The order of metal concentration was Zn > Pb > Cu (or Cu > Pb) > Cr > Ni > As > Cd in all cases. The range of ∑11PAHs concentration was 634–1,371 ng/g dw (three to seven times greater than the amount in the pre-exposed lichens). The ∑11PAHs were dominated (>70 %) by compounds with three aromatic rings. The comparison of the levels of air pollutants among the monitored stations shows nonrelevant spatial patterns between the landfill stations and the control areas; the levels of PAHs and metals found in the lichen samples around the landfill seemed to be more related to the general diffusion of these pollutants in that area.
Atmospheric mercury emissions from mine-waste enriched soils were measured in order to compare the mercury fluxes of bare soils with those from other soils covered by native grasses. Our research was ...conducted near Mt. Amiata in central Italy, an area that was one of the largest and most productive mining centers in Europe up into the 1980s. To determine in situ mercury emissions, we used a Plexiglas flux chamber connected to a portable mercury analyzer (Lumex RA-915+). This allowed us to detect, in real time, the mercury vapor in the air, and to correlate this with the meteorological parameters that we examined (solar radiation, soil temperature, and humidity). The highest mercury flux values (8000ngm−2h−1) were observed on bare soils during the hours of maximum insulation, while lower values (250ngm−2h−1) were observed on soils covered by native grasses. Our results indicate that two main environmental variables affect mercury emission: solar radiation intensity and soil temperature. The presence of native vegetation, which can shield soil surfaces from incident light, reduced mercury emissions, a result that we attribute to a drop in the efficiency of mercury photoreduction processes rather than to decreases in soil temperature. This finding is consistent with decreases in mercury flux values down to 3500ngm−2h−1, which occurred under cloudy conditions despite high soil temperatures. Moreover, when the soil temperature was 28°C and the vegetation was removed from the experimental site, mercury emissions increased almost four-fold. This increase occurred almost immediately after the grasses were cut, and was approximately eight-fold after 20h. Thus, this study demonstrates that enhancing wild vegetation cover could be an inexpensive and effective approach in fostering a natural, self-renewing reduction of mercury emissions from mercury-contaminated soils.
► Mercury air/surface exchange from grass covered soil is different from bare soil. ► Light enhances mercury emissions and is the main parameter driving the process. ► The presence of wild vegetation covering the soil reduces mercury emission. ► Vegetative covers could be a solution to reduce atmospheric mercury pollution.
It is well established that the dissolved gaseous mercury (DGM) production in waters is mainly driven by photochemical processes. The present paper provides evidence for a significant ...bacteria-mediated DGM production, occurring also under dark conditions in environmentally different types of coastal water bodies of the Mediterranean basin. The DGM production was laboratory determined in sea, lagoon-brackish and lake water samples, comparing the efficiency of the DGM production processes in darkness and in the light. This latter condition was established by exposing samples at solar radiation intensity in the Photosyntetical Active Radiation region (PAR) of 200 W m
−
2
. Mercury reduction rate in the dark was of the order of 2–4% of the DGM production in lightness, depending on the total mercury concentration in the water, rather than the bacterial abundance in it. Support for the active bacterial role in mercury reduction rate under dark conditions was provided by: 1) absence of significant DGM production in sterilized water samples (following filtration treatment or autoclaving), 2) restored DGM production efficiency, following re-inoculation into the same water samples of representatives of their bacterial community, previously isolated and separately cultured. Notwithstanding the low bacteria-mediated vs. the high photo-induced DGM production, whatever natural water body was considered, it is worth stressing the significant contribution of this organismal-mediated process to oceanic mercury evasion, since it occurs continuously along the entire water column throughout the 24 h of the day.
Mercury evasional fluxes from the sea surface into the atmosphere play an important role in the Hg biogeochemical cycle, especially in the Mediterranean basin, which is characterized by the presence ...of large cinnabar deposits, intense solar radiation and high temperatures for many months of the year. Since the available experimental methodologies to measure mercury flux can be used only in good weather conditions, at present it is necessary to make use of exchange models that require the knowledge of the dissolved gaseous mercury (DGM) concentration in seawater. In this paper, the main factors affecting DGM levels are discussed considering the determination of the DGM daily behaviour in different meteo-marine and weather conditions at coastal and offshore locations of the Mediterranean basin. A fully automatic device for continuous analyses of DGM concentration with a high time resolution was used. Results show that the daily trend of DGM concentration tracks that of the solar radiation intensity, often mapping the movement of the clouds. DGM levels can be decreased by the presence of high winds that increase mercury evasion from the water surface, as well as by the mixing of the surface water layer. The presence of high levels of dissolved organic matter favours the photo-induced reduction of mercury as observed by the measurements performed in a lagoon water.
The 2016–2017 seismic events that struck central Italy led the Government to carry out a project to produce the third level Seismic Microzonation studies in 138 municipalities. These activities have ...involved many experts in different disciplines such as geology, geomorphology, geophysics, seismology and geotechnical engineering. This project represented the first opportunity to perform nationally coordinated third level Seismic Microzonation studies over a wide area in a quite short time (6 months). It provided the chance to improve methodological procedures, to test the reliability of methods and models for site response analyses and to produce a huge amount of validated data. This paper focuses on the contribution of geological disciplines and concerns: (a) the definition of the main “morphostructural domains” of the Central-Northern Apennines; (b) the creation of an archive of all the lithostratigraphic units occurring in the study area with their conversion into engineering-geological units and their distribution in the different morphostructural domains; (c) the construction of the reference geological and geotechnical models, which are essential to classify the territory into seismically homogeneous microzones and to perform the successive 1D and 2D numerical analyses of the local site response. The geophysical dataset acquired for the study allowed a first statistical characterization of the Vs values typical of the engineering-geological units identified in this study. Some examples of the recurrent geological and geotechnical models are shown to explain the complexity and variety of the geological and geomorphological features of the investigated area and to highlight the different seismostratigraphic behavior of rocks and cover terrains. The analysis of third level Seismic Microzonation data made it possible to identify recurrent subsoil models and to note the main stratigraphic and morphological control-factors of the ground motion modification in the different morphostructural domains.
Magnetic resonance imaging (MRI) with a dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) sequence to study brain tumours provides information on the haemodynamic characteristics ...of the neoplastic tissue. Brain perfusion maps and calculation of perfusion parameters, such as relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV) and mean transit time (MTT) allow assessment of vascularity and angiogenesis within tumours of the central nervous system (CNS), thus providing additional information to conventional MRI sequences. Although DSC-PWI has long been used, its clinical use in the study of brain tumours in daily clinical practice is still to be defined. The aim of this review was to analyse the application of perfusion MRI in the study of brain tumours by summarising our personal experience and the main results reported in the literature.
The atmospheric pathway of the global mercury flux is known to be the primary source of mercury contamination to most threatened aquatic ecosystems. Notwithstanding, the emission of mercury from ...surface water to the atmosphere is as much as 50% of total annual emissions of this metal into the atmosphere. In recent years, much effort has been made in theoretical and experimental researches to quantify the total mass flux of mercury to the atmosphere. In this study the most recent atmospheric modelling methods and the information obtained from them are presented and compared using experimental data collected during the Oceanographic Campaign Fenice 2011 (25 October – 8 November 2011), performed on board the Research Vessel (RV) Urania of the CNR in the framework of the MEDOCEANOR ongoing program. A strategy for future numerical model development is proposed which is intended to gain a better knowledge of the long-term effects of meteo-climatic drivers on mercury evasional processes, and would provide key information on gaseous Hg exchange rates at the air-water interface.
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