118 research outputs found
Sex and gender optometry: from retinal design to stereopsis
Scientific research in optometry aims to increase the ability to predict optical effects induced by lens fitting, allowing us to understand how geometrical concepts and physical phenomena translate into perceptual responses. It is possible, for instance, to investigate how differential perspective affects three-dimensional perception, indeed the ocular parallax error, that occurs as the eyes are separated horizontally by a certain distance (DAV), allows for the depth interval between two object points to be appreciated and transferred to the retina. In a study conducted at the University of Turin, the DAVs measured on a group of students were compared with the students’ stereo acuity values, with the aim of highlighting whether female subjects, whose DAVs are smaller than those of men, actually have less sense of depth. The measurement protocol and the results obtained will be explained. The research perspective is the parameterization of optometric tests to take into account differences due to gender, in order to detect any abnormalities more accurately
First Ex-Vivo Validation of a Radioguided Surgery Technique with beta- Radiation
Purpose: A radio-guided surgery technique with beta- -emitting radio-tracers
was suggested to overcome the effect of the large penetration of gamma
radiation. The feasibility studies in the case of brain tumors and abdominal
neuro-endocrine tumors were based on simulations starting from PET images with
several underlying assumptions. This paper reports, as proof-of-principle of
this technique, an ex-vivo test on a meningioma patient. This test allowed to
validate the whole chain, from the evaluation of the SUV of the tumor, to the
assumptions on the bio-distribution and the signal detection.
Methods: A patient affected by meningioma was administered 300 MBq of
90Y-DOTATOC. Several samples extracted from the meningioma and the nearby Dura
Mater were analyzed with a beta- probe designed specifically for this
radio-guided surgery technique. The observed signals were compared both with
the evaluation from the histology and with the Monte Carlo simulation.
Results: we obtained a large signal on the bulk tumor (105 cps) and a
significant signal on residuals of 0.2 ml (28 cps). We also show that
simulations predict correctly the observed yields and this allows us to
estimate that the healthy tissues would return negligible signals (~1 cps).
This test also demonstrated that the exposure of the medical staff is
negligible and that among the biological wastes only urine has a significant
activity.
Conclusions: This proof-of-principle test on a patient assessed that the
technique is feasible with negligible background to medical personnel and
confirmed that the expectations obtained with Monte Carlo simulations starting
from diagnostic PET images are correct.Comment: 17 pages, 4 Figs, Accepted by Physica Medic
Performance assessment of a tightly baffled, long-legged divertor configuration in TCV with SOLPS-ITER
Numerical simulations explore the possibility to test the tightly baffled,
long-legged divertor (TBLLD) concept in a future upgrade of the Tokamak \`a
configuration variable (TCV). The SOLPS-ITER code package is used to compare
the exhaust performance of several TBLLD configurations with existing unbaffled
and baffled TCV configurations. The TBLLDs feature a range of radial gaps
between the separatrix and the outer leg side walls. All considered TBLLDs are
predicted to lead to a denser and colder plasma in front of the targets and
improve the power handling by factors of 2-3 compared to the present, baffled
divertor and by up to a factor of 12 compared to the original, unbaffled
configuration. The improved TBLLD performance is mainly due to a better neutral
confinement with improved plasma-neutral interactions in the divertor region.
Both power handling capability and neutral confinement increases when reducing
the radial gap. The core compatibility of TBLLDs with nitrogen seeding is also
evaluated and the detachment window with acceptable core pollution for the
proposed TBLLDs is explored, showing a reduction of required upstream impurity
concentration up to 18% to achieve the detachment with thinner radial gap
Distilling the topology of the Hofstadter model through a diffraction experiment
In two and three spatial dimensions, the transverse response experienced by a
charged particle on a lattice in a uniform magnetic field is proportional to a
topological invariant, the first Chern number, characterizing the energy bands
of the underlying Hofstadter Hamiltonian. In four dimensions, the transverse
response is also quantized, and controlled by the second Chern number. These
remarkable features solely arise from the magnetic translational symmetry. Here
we show that the symmetries of the two-, three- and four-dimensional Hofstadter
Hamiltonians may be encrypted in optical diffraction gratings, such that simple
photonic experiments allow one to extract the first and the second Chern
numbers of the whole energy spectra. This result is particularly remarkable in
three and four dimensions, where complete topological characterizations have
not yet been achieved experimentally. Side-by-side to the theoretical analysis,
in this work we present the experimental study of optical gratings analogues of
the two- and three-dimensional Hofstadter models
SOLPS-ITER validation with TCV L-mode discharges editors-pick
This work presents a quantitative test of SOLPS-ITER simulations against tokamak a configuration variable (TCV) L-mode experiments. These simulations account for drifts, currents, kinetic neutrals, and carbon impurities providing the most complete edge transport simulations for TCV to date. The comparison is performed on nominally identical discharges carried out to assess the effectiveness of TCV's divertor baffles in the framework of the European Plasma Exhaust program and employs numerous edge diagnostics providing a detailed code-experiment benchmark for TCV. The simulations show a qualitative consistency, but the quantitative differences remain, which are assessed herein. It is found that, for a given separatrix density, the simulations most notably yield a colder, and denser, divertor state with a higher divertor neutral pressure than measured
A Root in Synapsis and the Other One in the Gut Microbiome-Brain Axis: Are the Two Poles of Ketogenic Diet Enough to Challenge Glioblastoma?
Glioblastoma is the most frequent and aggressive brain cancer in adults. While precision medicine in oncology has produced remarkable progress in several malignancies, treatment of glioblastoma has still limited available options and a dismal prognosis. After first-line treatment with surgery followed by radiochemotherapy based on the 2005 STUPP trial, no significant therapeutic advancements have been registered. While waiting that genomic characterization moves from a prognostic/predictive value into therapeutic applications, practical and easy-to-use approaches are eagerly awaited. Medical reports on the role of the ketogenic diet in adult neurological disorders and in glioblastoma suggest that nutritional interventions may condition outcomes and be associated with standard therapies. The acceptable macronutrient distribution of daily calories in a regular diet are 45–65% of daily calories from carbohydrates, 20–35% from fats, and 10–35% from protein. Basically, the ketogenic diet follows an approach based on low carbohydrates/high fat intake. In carbohydrates starvation, body energy derives from fat storage which is used to produce ketones and act as glucose surrogates. The ketogenic diet has several effects: metabolic interference with glucose and insulin and IGF-1 pathways, influence on neurotransmission, reduction of oxidative stress and inflammation, direct effect on gene expression through epigenetic mechanisms. Apart from these central effects working at the synapsis level, recent evidence also suggests a role for microbiome and gut-brain axis induced by a ketogenic diet. This review focuses on rationales supporting the ketogenic diet and clinical studies will be reported, looking at future possible perspectives
Comparison of whole-body diffusion-weighted magnetic resonance and FDG-PET/CT in the assessment of Hodgkin's lymphoma for staging and treatment response
Computed tomography (CT), 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and hybrid FDG-PET/CT are the most commonly used diagnostic tools for the initial staging and treatment response assessment of lymphomas [1]. The aim of this report is to compare the correlations between functional imaging markers derived from FDG-PET/CT and whole-body, diffusion-weighted magnetic resonance imaging (DW-MRI) in a young patient affected by Hodgkin's lymphoma (HL)
A Web-based spatial decision supporting system for land management and soil conservation
Abstract. Today it is evident that there are many contrasting demands on our landscape (e.g. food security, more sustainable agriculture, higher income in rural areas, etc.) as well as many land degradation problems. It has been proved that providing operational answers to these demands and problems is extremely difficult. Here we aim to demonstrate that a spatial decision support system based on geospatial cyberinfrastructure (GCI) can address all of the above, so producing a smart system for supporting decision making for agriculture, forestry, and urban planning with respect to the landscape. In this paper, we discuss methods and results of a special kind of GCI architecture, one that is highly focused on land management and soil conservation. The system allows us to obtain dynamic, multidisciplinary, multiscale, and multifunctional answers to agriculture, forestry, and urban planning issues through the Web. The system has been applied to and tested in an area of about 20 000 ha in the south of Italy, within the framework of a European LIFE+ project (SOILCONSWEB). The paper reports – as a case study – results from two different applications dealing with agriculture (olive growth tool) and environmental protection (soil capability to protect groundwater). Developed with the help of end users, the system is starting to be adopted by local communities. The system indirectly explores a change of paradigm for soil and landscape scientists. Indeed, the potential benefit is shown of overcoming current disciplinary fragmentation over landscape issues by offering – through a smart Web-based system – truly integrated geospatial knowledge that may be directly and freely used by any end user (www.landconsultingweb.eu). This may help bridge the last very important divide between scientists working on the landscape and end users
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