167 research outputs found
Vox2Vox: 3D-GAN for Brain Tumour Segmentation
Gliomas are the most common primary brain malignancies, with different
degrees of aggressiveness, variable prognosis and various heterogeneous
histological sub-regions, i.e., peritumoral edema, necrotic core, enhancing and
non-enhancing tumour core. Although brain tumours can easily be detected using
multi-modal MRI, accurate tumor segmentation is a challenging task. Hence,
using the data provided by the BraTS Challenge 2020, we propose a 3D
volume-to-volume Generative Adversarial Network for segmentation of brain
tumours. The model, called Vox2Vox, generates realistic segmentation outputs
from multi-channel 3D MR images, segmenting the whole, core and enhancing tumor
with mean values of 87.20%, 81.14%, and 78.67% as dice scores and 6.44mm,
24.36mm, and 18.95mm for Hausdorff distance 95 percentile for the BraTS testing
set after ensembling 10 Vox2Vox models obtained with a 10-fold
cross-validation
What is the best data augmentation for 3D brain tumor segmentation?
Training segmentation networks requires large annotated datasets, which in
medical imaging can be hard to obtain. Despite this fact, data augmentation has
in our opinion not been fully explored for brain tumor segmentation. In this
project we apply different types of data augmentation (flipping, rotation,
scaling, brightness adjustment, elastic deformation) when training a standard
3D U-Net, and demonstrate that augmentation significantly improves the
network's performance in many cases. Our conclusion is that brightness
augmentation and elastic deformation work best, and that combinations of
different augmentation techniques do not provide further improvement compared
to only using one augmentation technique. Our code is available at
https://github.com/mdciri/3D-augmentation-techniques
NO2 Dispersion Model Of Emissions Of A 20 kWe Biomass Gasifier
Biomass valorization represents a simple way to reduce Green House Gases emissions. However, the biomass-to-energy field is limited by high gaseous emission concentrations. Innovative abatement technologies can make gaseous emissions close to zero. In this work, three different NO2 abatement technologies were assessed and compared. A deterministic approach was used to estimate NO2 concentrations using experimental concentrations at the chimney for a 20 kWe biomass gasifier. The gasifier
chimney was described as an equivalent stack. The pollutant propagation was simulated with a Gaussian plume dispersion model. On this purpose, the unknown equivalent stack flow rate in the model was adjusted using the available data of NO2 on the ground, considering the changing of the air stability between nighttime and daytime and the variable wind direction. Thanks to pollutants dispersion modeling, the evaluation of the
optimal abatement technology was possible, investigating the potential effect produced on people and the environment. Results show a bioscrubber technology as the best one to reduce NO2 concentrations at 100, 1000, 3000 m from the emission point of 74, 75, 70 %, respectively
Environmental Impact Analysis of Flue Gases Emissions for a 20 Kwe Biomass Gasifier
Due to the potential ability to support local development, create local employment, and contribute to climate change mitigation decentralized bioenergy CHP systems are receiving increasing attention. With bioenergy CHP systems are possible to achieve energy efficiency by converting primary energy to heat and electricity, replacing fossil fuels and reducing carbon dioxide emissions in the atmosphere. In particular, biomass
cogeneration is considered a reliable efficient energy production technology and an effective alternative to reduce greenhouse gas emissions due to their low CO2 emission, using near biomass production sites (e.g., agricultural activities, forestes), avoiding long supply chains. In this paper, a techno-environmental assessment for a biomass powered micro-scale CHP system based on gasifier combined with an internal combustion engine sized for a maximum electrical and thermal output of 20 kWe and 40 kWth, is analyzed.
CO2 direct emissions and CO2 equivalent emissions for NO2, CO, HC were assessed in order to obtain the final environmental impact of the plant. Several cases were considered changing biomass kind and flue gas treatment systems. Results show that biomass kind has not an impact on the toxic gas emissions, while the bioscrubber is the best flue gas treatment technology to reduce concentrations of all pollutants
Social network data analysis to highlight privacy threats in sharing data
AbstractSocial networks are a vast source of information, and they have been increasing impact on people's daily lives. They permit us to share emotions, passions, and interactions with other people around the world. While enabling people to exhibit their lives, social networks guarantee their privacy. The definitions of privacy requirements and default policies for safeguarding people's data are the most difficult challenges that social networks have to deal with. In this work, we have collected data concerning people who have different social network profiles, aiming to analyse privacy requirements offered by social networks. In particular, we have built a tool exploiting image-recognition techniques to recognise a user from his/her picture, aiming to collect his/her personal data accessible through social networks where s/he has a profile. We have composed a dataset of 5000 users by combining data available from several social networks; we compared social network data mandatory in the registration phases, publicly accessible and those retrieved by our analysis. We aim to analyse the amount of extrapolated data for evaluating privacy threats when users share information on different social networks to help them be aware of these aspects. This work shows how users data on social networks can be retrieved easily by representing a clear privacy violation. Our research aims to improve the user's awareness concerning the spreading and managing of social networks data. To this end, we highlighted all the statistical evaluations made over the gathered data for putting in evidence the privacy issues
Ameliorating a Complex Urban Ecosystem Through Instrumental Use of Softscape Buffers: Proposal for a Green Infrastructure Network in the Metropolitan Area of Naples
Green Infrastructure (GI) definition, deriving from the United States green infrastructure
for hydro-geological rebalancing through imitating the nature stormwater management,
was consolidated in Europe by GI Planning Guide. Nowadays GI can be considered
a valid and meaningful approach for ameliorating urban complex ecosystems, and
could also be considered as mitigation action of land consumption, according to the
guidelines on the soil sealing of the European Commission (2012). The metropolitan
area of Naples located in south Italy is characterized by an unauthorized and chaotic
urban development. The land-use map reported an average of 30% of urbanization in
the metropolitan area, rising up to 50â60% and as high as 98% in the north core area of
the city. This high level of urbanization is directly related to the habitat fragmentation. The
National Biodiversity Conservation Strategy defines several challenges and targets to
counteract the biodiversity loss in Italy, identifying urban areas as places exposed to the
greatest pressures on ecosystems. Therefore, the integration of different policies limiting
habitat fragmentation, heat island effect and natural soil hydro-geological degradation
into spatial planning, especially through green corridors and ecosystem enhancement
in urban areas is an urgent need for the society. Spatial planning has to be renewed
in metropolitan areas, where threats and weaknesses to biodiversity conservation are
stronger than in any other place, according to the Law n. 56/2014, (Gazzetta Ufficiale
della Repubblica Italiana, 2014) committing metropolitan cities to the enactment of
General Territorial Plan. In the current paper, we aim at designing an ecological network
for the metropolitan area of Naples one of the biggest city of southern Italy. The analyses
include the adopted methodological procedure, i.e., ecological network analysis and
design, and the introductory elements of a spatial analysis on a pilot ecological network
of several patches. Finally, the paper illustrates the network analysis conceived as a
monitoring system and also in future perspective, as a planning support system
A Review on the Antimicrobial Activity of Schiff Bases: Data Collection and Recent Studies
Schiff bases (SBs) have extensive applications in different fields such as analytical, inorâ
ganic and organic chemistry. They are used as dyes, catalysts, polymer stabilizers, luminescence
chemosensors, catalyzers in the fixation of CO2 biolubricant additives and have been suggested for
solar energy applications as well. Further, a wide range of pharmacological and biological applicaâ
tions, such as antimalarial, antiproliferative, analgesic, antiâinflammatory, antiviral, antipyretic, anâ
tibacterial and antifungal uses, emphasize the need for SB synthesis. Several SBs conjugated with
chitosan have been studied in order to enhance the antibacterial activity of chitosan. Moreover, the
use of the nanoparticles of SBs may improve their antimicrobial effects. Herein, we provide an anaâ
lytical overview of the antibacterial and antifungal properties of SBs and chitosanâbased SBs as well
as SBsâfunctionalized nanoparticles. The most relevant and recent literature was reviewed for this
purpose
Anthocyanins are Key Regulators of Drought Stress Tolerance in Tobacco
Abiotic stresses will be one of the major challenges for worldwide food supply in the near future. Therefore, it is important to understand the physiological mechanisms that mediate plant responses to abiotic stresses. When subjected to UV, salinity or drought stress, plants accumulate specialized metabolites that are often correlated with their ability to cope with the stress. Among them, anthocyanins are the most studied intermediates of the phenylpropanoid pathway. However, their role in plant response to abiotic stresses is still under discussion. To better understand the effects of anthocyanins on plant physiology and morphogenesis, and their implications on drought stress tolerance, we used transgenic tobacco plants (AN1), which over-accumulated anthocyanins in all tissues. AN1 plants showed an altered phenotype in terms of leaf gas exchanges, leaf morphology, anatomy and metabolic profile, which conferred them with a higher drought tolerance compared to the wild-type plants. These results provide important insights for understanding the functional reason for anthocyanin accumulation in plants under stress
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