74 research outputs found
image guided ablations for thyroid tumours
Image guided ablations might be regarded as a promising effective and safe alternative for treatment of recurrent thyroid cancer in particular in patients with high surgical risk or refusing surgery. Furthermore, image guided ablations seems to represent a promising alternative to surgery or observation for micropapillary thyroid carcinoma, with the aim of providing an effective treatment with minimal invasiveness. Further studies are necessary to confirm the role in this settin
Information dynamics algorithm for detecting communities in networks
The problem of community detection is relevant in many scientific
disciplines, from social science to statistical physics. Given the impact of
community detection in many areas, such as psychology and social sciences, we
have addressed the issue of modifying existing well performing algorithms by
incorporating elements of the domain application fields, i.e. domain-inspired.
We have focused on a psychology and social network - inspired approach which
may be useful for further strengthening the link between social network studies
and mathematics of community detection. Here we introduce a community-detection
algorithm derived from the van Dongen's Markov Cluster algorithm (MCL) method
by considering networks' nodes as agents capable to take decisions. In this
framework we have introduced a memory factor to mimic a typical human behavior
such as the oblivion effect. The method is based on information diffusion and
it includes a non-linear processing phase. We test our method on two classical
community benchmark and on computer generated networks with known community
structure. Our approach has three important features: the capacity of detecting
overlapping communities, the capability of identifying communities from an
individual point of view and the fine tuning the community detectability with
respect to prior knowledge of the data. Finally we discuss how to use a Shannon
entropy measure for parameter estimation in complex networks.Comment: Submitted to "Communication in Nonlinear Science and Numerical
Simulation
A two-component parameterization of marine ice-nucleating particles based on seawater biology and sea spray aerosol measurements in the Mediterranean Sea
Ice-nucleating particles (INPs) have a large impact on the climate-relevant properties of clouds over the oceans. Studies have shown that sea spray aerosols (SSAs), produced upon bursting of bubbles at the ocean surface, can be an important source of marine INPs, particularly during periods of enhanced biological productivity. Recent mesocosm experiments using natural seawater spiked with nutrients have revealed that marine INPs are derived from two separate classes of organic matter in SSAs. Despite this finding, existing parameterizations for marine INP abundance are based solely on single variables such as SSA organic carbon (OC) or SSA surface area, which may mask specific trends in the separate classes of INP. The goal of this paper is to improve the understanding of the connection between ocean biology and marine INP abundance by reporting results from a field study and proposing a new parameterization of marine INPs that accounts for the two associated classes of organic matter. The PEACETIME cruise took place from 10 May to 10 June 2017 in the Mediterranean Sea. Throughout the cruise, INP concentrations in the surface microlayer (INPSML) and in SSAs (INPSSA) produced using a plunging aquarium apparatus were continuously monitored while surface seawater (SSW) and SML biological properties were measured in parallel. The organic content of artificially generated SSAs was also evaluated. INPSML concentrations were found to be lower than those reported in the literature, presumably due to the oligotrophic nature of the Mediterranean Sea. A dust wet deposition event that occurred during the cruise increased the INP concentrations measured in the SML by an order of magnitude, in line with increases in iron in the SML and bacterial abundances. Increases in INPSSA were not observed until after a delay of 3 days compared to increases in the SML and are likely a result of a strong influence of bulk SSW INPs for the temperatures investigated (T=â18ââC for SSAs, T=â15ââC for SSW). Results confirmed that INPSSA are divided into two classes depending on their associated organic matter. Here we find that warm (Tâ„â22ââC) INPSSA concentrations are correlated with water-soluble organic matter (WSOC) in the SSAs, but also with SSW parameters (particulate organic carbon, POCSSW and INPSSW,â16C) while cold INPSSA (T<â22ââC) are correlated with SSA water-insoluble organic carbon (WIOC) and SML dissolved organic carbon (DOC) concentrations. A relationship was also found between cold INPSSA and SSW nano- and microphytoplankton cell abundances, indicating that these species might be a source of water-insoluble organic matter with surfactant properties and specific IN activities. Guided by these results, we formulated and tested multiple parameterizations for the abundance of INPs in marine SSAs, including a single-component model based on POCSSW and a two-component model based on SSA WIOC and OC. We also altered a previous model based on OCSSA content to account for oligotrophy of the Mediterranean Sea. We then compared this formulation with the previous models. This new parameterization should improve attempts to incorporate marine INP emissions into numerical models
The rapid spread of SARS-COV-2 Omicron variant in Italy reflected early through wastewater surveillance
The SARS-CoV-2 Omicron variant emerged in South Africa in November 2021, and has later been identified worldwide, raising serious concerns. A real-time RT-PCR assay was designed for the rapid screening of the Omicron variant, targeting characteristic mutations of the spike gene. The assay was used to test 737 sewage samples collected throughout Italy (19/21 Regions) between 11 November and 25 December 2021, with the aim of assessing the spread of the Omicron variant in the country. Positive samples were also tested with a real-time RT-PCR developed by the European Commission, Joint Research Centre (JRC), and through nested RT-PCR followed by Sanger sequencing. Overall, 115 samples tested positive for Omicron SARS-CoV-2 variant. The first occurrence was detected on 7 December, in Veneto, North Italy. Later on, the variant spread extremely fast in three weeks, with prevalence of positive wastewater samples rising from 1.0% (1/104 samples) in the week 5-11 December, to 17.5% (25/143 samples) in the week 12-18, to 65.9% (89/135 samples) in the week 19-25, in line with the increase in cases of infection with the Omicron variant observed during December in Italy. Similarly, the number of Regions/Autonomous Provinces in which the variant was detected increased from one in the first week, to 11 in the second, and to 17 in the last one. The presence of the Omicron variant was confirmed by the JRC real-time RT-PCR in 79.1% (91/115) of the positive samples, and by Sanger sequencing in 66% (64/97) of PCR amplicons. In conclusion, we designed an RT-qPCR assay capable to detect the Omicron variant, which can be successfully used for the purpose of wastewater-based epidemiology. We also described the history of the introduction and diffusion of the Omicron variant in the Italian population and territory, confirming the effectiveness of sewage monitoring as a powerful surveillance tool
Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic
This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic
Discrepancy between Ice Particles and Ice Nuclei in Mixed Clouds: Critical Aspects
Measurements of ice crystal concentrations in mixed clouds tend to exceed ice
nucleus concentrations measured in nearby clear air. This discrepancy is a
source of uncertainty in climate change projections as the radiative properties
of mixed phase clouds are largely determined by their liquid and ice water
content. The ice enhancement process can sometimes depend on secondary
ice production, which can occur through ice crystal fracture during sublimation,
cloud drop shattering during freezing or following collision with ice particles.
However, the discrepancy is observed even in mixed clouds where only
primary ice nucleation processes occur. Several hypotheses have been suggested
for the observed discrepancies. One factor could be the existence in
clouds of pockets of high vapor supersaturation formed by droplet freezing or
removal of small droplets by collision with larger droplets, associated with the
fact that ice crystal concentration increases with water supersaturation. However,
ice crystal concentrations are usually measured at near water saturation.
Additional factors could be drop freezing during evaporation and activation
of droplet evaporation residues. Here we suggest that a major factor could be
underestimation of the contact freezing mode as it is not measured in experimental
campaigns and seldom considered in nucleation models. Laboratory
experiments give only incomplete answers to the important questions concerning
the contact freezing mode, e.g. what fraction of the aerosol particles
that come into contact with the droplet surface results in a freezing event and
what is the influence of particle type and size, air temperature and relative
humidity. As supercooled droplets grow or evaporate in mixed clouds, phoretic
forces should play an important role in the collision efficiency between
aerosol and droplets, and consequently in contact freezing. A further question
is the possibility that aerosol, usually not active in deposition or condensation/
immersion freezing, can trigger ice nucleation by colliding with supercooled
droplets
Of time, activity, and consumer behavior: An essay on findings, interpretations, and needed research
Bench-scale investigation of inclined dense jets
In this work experimental data on the geometry of dense inclined jets issuing in a lab-scale glass rectangular tank are presented. The surrounding fluid was always tap water at room temperature while the dense jets were water solutions of NaCl. Four parameters were changed in the experiments, namely nozzle diameter and inclination, and jet density and flow rate. Jet trajectories were revealed by a colored tracer. Images of the jet were recorded by a digital camera and then further digitally processed, eventually resulting in a time-averaged tracer intensity field. All the jet geometrical parameters, once normalized, were found to be very well correlated to the Densimetric Froude number. Moderate jet viscosity variations were found non to significantly affect jet behavior. The reported data allow a quick and easy estimation of maximum rise level, position of the trajectory maximum and impact point distance of dense jets issued at different angles above the horizontal
6-Keto-prostaglandin E1-sensitive adenylate cyclase and binding sites in membranes from platelets and cultured smooth muscle cells.
6-keto-PGE1 elicits the same biological effects as PGI2 in human platelets and in rabbit aorta and mesenteric artery, being, however, less potent. We report here that 6-keto-PGE1 dose-dependently stimulates adenylate cyclase activity in membranes of human platelets and cultured myocytes from rabbit aorta and
mesenteric artery. The extent of stimulation of the enzyme by 6-keto-PGE1 is the same as elicited by PGI2, while the apparent affinity is lower than that of prostacyclin, both in platelets and in vascular smooth muscle cells. At the level of platelet membranes, 6-keto-PGE1 interacts with the binding sites labelled by
PGI2. However, in platelets as well as in mesenteric artery myocytes, 6-keto-PGE1 interacts with only one class of sites as demonstrated either by binding or by adenylate cyclase studies, whereas PGI2 in the same conditions recognizes two different classes
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