322 research outputs found
Reconstructed SPECT images of 177Lu homogeneous cylindrical phantom used for calibration and texture analysis
In a clinical contest, it is common to use dedicated phantoms to perform quality assurance test to check the performance of a SPECT system. Some of these phantoms are also used to calibrate the system for dosimetric evaluation of patients undergoing radiometabolic cancer therapy. In this work, a 3D-OSEM reconstructed Lu-177 SPECT dataset of a homogeneous cylindrical phantom is described. This dataset was acquired to investigate the variation of the SPECT calibration factor, counts convergence, noise and uniformity by varying the number of subsets and iterations. In particular, the dataset is composed of images reconstructed using five different numbers of subsets and sixteen different numbers of iterations, for a total of 80 different configurations. The dataset is suitable for comparison with other reconstruction algorithms (e.g. FBP, MLEM, etc.) and radionuclides (e.g. technetium, yttrium). In regards to the uniformity issue, the same dataset allows the user to perform radiomic investigations on the influence of the border effect on the reconstructed images
Proton induced Dark Count Rate degradation in 150-nm CMOS Single-Photon Avalanche Diodes
Proton irradiation effects on a Single-Photon Avalanche Diodes (SPADs) device
manufactured using a 150-nm CMOS process are presented. An irradiation campaign
has been carried out with protons of 20 MeV and 24 MeV on several samples of a
test chip containing SPADs arrays with two different junction layouts. The dark
count rate distributions have been analyzed as a function of the displacement
damage dose. Annealing and cooling have been investigated as possible damage
mitigation approaches. We also discuss, through a space radiation simulation,
the suitability of such devices on several space mission case-studies.Comment: This is an author-created, un-copyedited version of an article
accepted for publication/published in Nuclear Instruments and Methods in
Physics Research Section A. The Version of Record is available online at
https://doi.org/10.1016/j.nima.2019.16272
Fiske steps and hysteresis in YBa2Cu3O7 grain boundary Josephson junctions: Structural Information of the barrier by means of a nondestructive approach.
A deep analysis of the current-voltage _I-V_ characteristics of YBa2Cu3O7 grain boundary Josephson junctions _GBJJs_ allows us to go much farther than the usual calculus of the transport parameters. It is possible to construct a structural image of the barrier by an exhaustive and complementary analysis of both transport and electromagnetic parameters obtained from I-V curves. For such an approach, we have chosen the following three representative bicrystalline geometries: 24° _001_ asymmetric, 45° _100_ asymmetric, and 24° _001_ symmetric +45° _100_ asymmetric. The dependence of the product ICRN on the junction normal resistance is of the ICRN −1 type pointing to a SNINS model _S denotes superconductor, I denotes insulator, and N denotes normal metal_ for all our GBJJs. A satisfactory explanation of the discrepancy of the capacitance of the barrier estimated from Fiske resonance positions and hysteresis in the I-V curves needs of such a model. Moreover an estimation of the length of the normal regions adjacent to the crystallographic barrier can be made. This comparative analysis is presented in order to extract interesting information about the particular transport mechanisms involved in these GBJJs
ACHALASIA TREATMENT IMPROVES SPECIFIC SYMPTOMS AND QUALITY OF LIFE: VALIDATION OF AN ACHALASIA SPECIFIC QUALITY OF LIFE QUESTIONNAIRE
Background and aim:
Therapies for achalasia aim to patients’ symptom
relief, but they affect patient’s quality of life (QoL), too. An ad hoc question-
naire evaluating both achalasia-related symptoms and disease related QoL is
lacking.
Aim: To validate a disease specific QoL questionnaire in perspectively
evaluated Italian achalasia patients.
Material and methods:
22 consecutive achalasia patients (4 men, age range
19–86 years) were included in the study. At baseline a structured question-
naire was used to evaluate both esophageal symptoms and disease specific
QoL. Questionnaire graded achalasia-related symptoms severity (dysphagia for solids and liquids, food regurgitation, chest pain, nocturnal cough) from 0
to 3, based on their impact on daily activities. Also a disease specific QoL was
evaluated by a self administred questionnaire, the AE-18, that investigated
four domains (physical, psychological and social functioning, and sleep dis-
turbance). Scores for each item range from 1
(“always”) to 5 (“never”); higher
scores corresponding to better quality of life. All patients were questioned
before, 1 and 6 months after a specific t
reatment regimen, that according
to patients clinical status consisted in pneumatic dilation, botulinum toxin
injection or surgical myotomy.
Results:
Patients within each specific treatment groups were the following
(3/22 surgical myotomy, 14/22 pneumatic dilation and 5/22 Botox injections,
respectively. In the table are reported the baseline demographics and achalasia-
related symptoms’ severity and QoL (data are expressed as mean
±
SD) within
each treatments group.
Table 1
Surgery group Dilation group Botox group p
Age at diagnosis
42.3
±
6.5 42.3
±
13 81.8
±
4.8
<
0.001
Age at onset of symptoms
39.3
±
7.5 40.3
±
12.4 80.8
±
5.6
<
0.001
Dysphagia for solids
2.7
±
0.6 2.2
±
0.7 2.2
±
0.5 0.5
Dysphagia for liquids
2.0
±
1.0 2.1
±
0.7 2.2
±
0.5 0.9
Regurgitation of undigested food 1.0
±
1.7 0.7
±
0.8 0.6
±
1.3 0.8
Chest pain
0.7
±
1.1 1.1
±
1.1 1.0
±
1.4 0.8
Nocturnal cough
1.3
±
1.5 1.3
±
1.2 1.0
±
1.4 0.9
AE-18 total score
54
±
14 53
±
12 53
±
11 0.9
At both 1 and 6 months of the follow-up, the severity mean scores of dysphagia
achalasia-related symptoms severity were significantly reduced compared to
baseline (p
<
0.05). Similarly, the AE-18 total score was significantly improved
(p
<
0.001).
Conclusions:
We showed that therapy-induced improvement of achalasia-
related symptoms correlate with a significant improvement of patients quality
of life as assessed by a specific questionnaire
Self-resonant modes in Josephson junctions with a phase discontinuity
We extend the theory of self-resonances in short Josephson junctions to the case of a piecewise constant critical current density and a κ discontinuity of the Josephson phase. We calculate the amplitudes of self-resonances as a function of applied magnetic field by using an extension of the approach introduced by Kulik for conventional Josephson junctions (I.O. Kulik, JETP Lett. 2,84 (1965)). The presented theory agrees with existing experiments on superconducting–insulator–ferromagnet–superconductor 0–π Josephson junctions. The results are relevant for the characterization of all modern 0–π junctions as well as 0–κ junctions with artificially created phase discontinuity: high-temperature grain boundary junctions, junctions with ferromagnetic barrier and the junction with current injectors
An annotated T2-weighted magnetic resonance image collection of testicular germ and non-germ cell tumors
open7noTesticular cancer is a rare tumor with a worldwide incidence that has increased over the last few decades. The majority of these tumors are testicular non-germ (TNGCTs) and germ cell tumors (TGCTs); the latter divided into two broad classes - seminomatous (SGCTs) and non-seminomatous germ cell tumors (NSGCTs). Although ultrasonography (US) maintains a primary role in the diagnostic workup of scrotal pathology, magnetic resonance imaging (MRI) has emerged as the imaging modality recommended for challenging cases, providing additional information to clarify inconclusive/equivocal US. In this work we describe and publicly share a collection of 44 images of annotated T2-weighted MRI lesions from 42 patients. Given that testicular cancer is a rare tumor, we are confident that this collection can be used to validate statistical models and to further investigate TNGCT and TGCT peculiarities using medical imaging features.openFeliciani G.; Mellini L.; Loi E.; Piccinini F.; Galeotti R.; Sarnelli A.; Parenti G.C.Feliciani G.; Mellini L.; Loi E.; Piccinini F.; Galeotti R.; Sarnelli A.; Parenti G.C
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Temperature-dependent electric noise level in different iron-based superconductors
A detailed characterization of the voltage-noise properties has been performed in FeTe0.5Se0.5 epitaxial thin films and Co-doped BaFe2As2 bilayers, deposited by pulsed laser deposition. In all the samples analyzed, the experimental voltage-spectral density has a 1/f noise component. Different behaviors are observed for the bias current and temperature dependencies of this 1/f noise, and are related to specific structural and electric transport properties of the two materials
Enteric glia: A new player in inflammatory bowel diseases
In addition to the well-known involvement of macrophages and neutrophils, other cell types have been recently reported to substantially contribute to the onset and progression of inflammatory bowel diseases (IBD). Enteric glial cells (EGC) are the equivalent cell type of astrocyte in the central nervous system (CNS) and share with them many neurotrophic and neuro-immunomodulatory properties. This short review highlights the role of EGC in IBD, describing the role played by these cells in the maintenance of gut homeostasis, and their modulation of enteric neuronal activities. In pathological conditions, EGC have been reported to trigger and support bowel inflammation through the specific over-secretion of S100B protein, a pivotal neurotrophic factor able to induce chronic inflammatory changes in gut mucosa. New pharmacological tools that may improve the current therapeutic strategies for inflammatory bowel diseases (IBD), lowering side effects (i.e. corticosteroids) and costs (i.e. anti-TNFα monoclonal antibodies) represent a very important challenge for gastroenterologists and pharmacologists. Novel drugs capable to modulate enteric glia reactivity, limiting the pro-inflammatory release of S100B, may thus represent a significant innovation in the field of pharmacological interventions for inflammatory bowel diseases
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