3,391 research outputs found
Towards Automated Semantic Segmentation in Mammography Images
Mammography images are widely used to detect non-palpable breast lesions or
nodules, preventing cancer and providing the opportunity to plan interventions
when necessary. The identification of some structures of interest is essential
to make a diagnosis and evaluate image adequacy. Thus, computer-aided detection
systems can be helpful in assisting medical interpretation by automatically
segmenting these landmark structures. In this paper, we propose a deep
learning-based framework for the segmentation of the nipple, the pectoral
muscle, the fibroglandular tissue, and the fatty tissue on standard-view
mammography images. We introduce a large private segmentation dataset and
extensive experiments considering different deep-learning model architectures.
Our experiments demonstrate accurate segmentation performance on variate and
challenging cases, showing that this framework can be integrated into clinical
practice.Comment: 6 page
Path dependent scaling of geometric phase near a quantum multi-critical point
We study the geometric phase of the ground state in a one-dimensional
transverse XY spin chain in the vicinity of a quantum multi-critical point. We
approach the multi-critical point along different paths and estimate the
geometric phase by applying a rotation in all spins about z-axis by an angle
. Although the geometric phase itself vanishes at the multi-critical
point, the derivative with respect to the anisotropy parameter of the model
shows peaks at different points on the ferromagnetic side close to it where the
energy gap is a local minimum; we call these points `quasi-critical'. The value
of the derivative at any quasi-critical point scales with the system size in a
power-law fashion with the exponent varying continuously with the parameter
that defines a path, upto a critical value .
For , or on the paramagnetic side no such peak is
observed. Numerically obtained results are in perfect agreement with analytical
predictions.Comment: 5 pages, 6 figure
Groupoids and an index theorem for conical pseudo-manifolds
We define an analytical index map and a topological index map for conical
pseudomanifolds. These constructions generalize the analogous constructions
used by Atiyah and Singer in the proof of their topological index theorem for a
smooth, compact manifold . A main ingredient is a non-commutative algebra
that plays in our setting the role of . We prove a Thom isomorphism
between non-commutative algebras which gives a new example of wrong way
functoriality in -theory. We then give a new proof of the Atiyah-Singer
index theorem using deformation groupoids and show how it generalizes to
conical pseudomanifolds. We thus prove a topological index theorem for conical
pseudomanifolds
Avaliação preliminar da microbiota nativa do Pome (palm oil mill effluent) para a produção de biogás.
(2R)-Ethyl 2-(5-bromo-2,3-dioxoindolin-1-yl)propanoate
The title compound, C13H12BrNO4, was obtained from an optically active aniline derivative. The structure was characterized by 1H NMR, 13C NMR, MS and X-ray diffraction techniques. 86% of the atoms of the two independent molecules in the asymmetric unit show non-crystallographic inversion symmetry
Adsorptive potential of Zn–Al and Mg–Fe layered double hydroxides for the removal of 2–nitrophenol from aqueous solutions
Two layered double hydroxides (LDH) of the type Zn–Al and Mg–Fe were synthesized, characterized and used as adsorbents to uptake 2–nitrophenol (2–NP) from aqueous solutions. XRD, FTIR, SEM, EDS, AFM and N2 adsorption/desorption curves were used to characterize the Zn–Al–LDH and Mg–Fe–LDH. The potential of both layered double hydroxides to adsorb 2–NP was investigated by adsorption kinetics, equilibrium, thermodynamics and consecutive adsorption/desorption cycles. The characterization indicated a high crystallinity degree and a well–organized and lamellar structure, confirming the efficiency of the synthesis. Elovich was the better kinetic model to describe the 2–NP adsorption onto Zn–Al–LDH, while Pseudo–second order was the best for Mg–Fe–LDH. For both LDHs, the adsorption equilibrium followed the Freundlich model. The process was endothermic, being the maximum adsorption capacities of 290 and 165 mg g–1 for Zn–Al–LDH and Mg–Fe–LDH, respectively. LDHs can be applied for five adsorption/desorption cycles with excellent adsorption capacities. It can be concluded that Zn–Al–LDH and Mg–Fe–LDH are promising materials to treat waters and wastewaters containing 2–nitropheno
First metallicity determination from Near-Infrared spectra for five obscured Cepheids discovered in the inner Disk
We report the discovery of five new classical Cepheids located in the inner Galactic Disk at longitude l ≃ −40° in our IRSF/SIRIUS Near-Infrared (NIR) variability survey. The new Cepheids are unique in probing the kinematics and metallicity of young stars at the transition between the inner Disk and the minor axis of the central Bar, where they are expected to be less affected by its dynamical influence. This is also the first time that metallicity of Cepheids is estimated on the basis of medium-resolution (R ∼ 3, 000) NIR spectra, and we validated our results with data in the literature, finding a minimal dependence on the adopted spectroscopic diagnostics. This result is very promising for using Cepheids as stellar proxy of the present-time chemical content of the obscured regions in the Disk. We found that the three Cepheids within 8–10 kpc from us have metallicities consistent with the mean radial metallicity gradient, and kinematics consistent with the Galactic rotation curve. Instead, the closest (∼4 kpc)/farthest (∼12 kpc) Cepheids have significant negative/positive residuals, both in velocity and in iron content. We discuss the possibility that such residuals are related to large-scale dynamical instabilities, induced by the bar/spiral-arm pattern, but the current sample is too limited to reach firm conclusion
Anti-inflammatory effects and possible mechanism of action of lupeol acetate isolated from Himatanthus drasticus (Mart.) Plumel
<p>Abstract</p> <p>Background</p> <p>The species <it>Himatanthus drasticus </it>is popularly known in Northeast Brazil as "janaguba" and belongs to the family Apocynaceae. The latex collected from its stem bark is used for several purposes including anti-inflammatory properties and presents among its bioactive constituents the pentacyclic triterpene lupeol. The objective of the present work was to study <it>in vivo </it>and <it>in vitro </it>the lupeol acetate (LA) isolated from the plant latex, in several models of inflammation.</p> <p>Methods</p> <p>Male Swiss mice (25-30 g, 6-24 animals per group) were administered with LA, 30 min before the test initiation. In the evaluation of analgesic activity the formalin test was used. The anti-inflammatory activity was evaluated by the following tests: paw edema induced by carrageenan and dextran, and the carrageenan-induced neutrophil migration into peritoneal cavities. Furthermore, the effect of LA on the myeloperoxidase release (MPO, an inflammation biomarker) from human neutrophils was also determined, as well as its antioxidant potential by the DPPH assay.</p> <p>Results</p> <p>In the formalin test, LA (10, 25 and 50 mg/kg, i.p.) inhibited both the 1<sup>st </sup>(neurogenic, 0-5 min) and mainly the 2<sup>nd </sup>(inflammatory, 20-25 min) phase. Naloxone completely reversed the LA effect, indicating the participation of the opioid system. LA also significantly inhibited carrageenan- and dextran-induced paw edemas, as well as the neutrophil migration to the peritoneal cavity evaluated by the carrageenan-induced pleurisia. In this model, the effect of a very low dose of LA (0.1 mg/kg) was potentiated by the same dose of pentoxifylline (PTX), a known TNF-alpha inhibitor. LA (25 and 50 μg/ml) was also very effective in inhibiting MPO released from stimulated human neutrophils, and significantly decreased the number of cells expressing iNOS activity in the paw of mice submitted to carrageenan-induced edema, suggesting a drug involvement with the NO system.</p> <p>Conclusions</p> <p>The anti-inflammatory effect of LA probably involves the opioid system, as indicated by the complete blockade of the opioid antagonist naloxone. Furthermore, the LA effect was potentiated by PTX (a TNF-alpha inhibitor). LA also decreased the number of iNOS cells, suggesting the participation of pro-inflammatory cytokines and the NO system in the drug action.</p
Pulsed ultrasound associated with gold nanoparticle gel reduces oxidative stress parameters and expression of pro-inflammatory molecules in an animal model of muscle injury
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