4,334 research outputs found
Oxidized Forms of Antiaromatic Oligomers of Biphenylene
Rsumen de la comunicaciónThe importance of antiaromatic molecules in Chemistry and more recently in material science is rising. In the particular case of applications in electronics, the antiaromatic skeleton offers the favorable situation of high energy (i.e., destabilized) occupied molecular orbitals allowing to ease oxidation, doping or electron transfer to form conductive and photo-active substrates.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
CDRNet: Accurate Cup-to-Disc Ratio Measurement with Tight Bounding Box Supervision in Fundus Photography Using Deep Learning
The cup-to-disc ratio (CDR) is one of the most significant indicator for
glaucoma diagnosis. Different from the use of costly fully supervised learning
formulation with pixel-wise annotations in the literature, this study
investigates the feasibility of accurate CDR measurement in fundus images using
only tight bounding box supervision. For this purpose, we develop a two-task
network named as CDRNet for accurate CDR measurement, one for weakly supervised
image segmentation, and the other for bounding-box regression. The weakly
supervised image segmentation task is implemented based on generalized multiple
instance learning formulation and smooth maximum approximation, and the
bounding-box regression task outputs class-specific bounding box prediction in
a single scale at the original image resolution. To get accurate bounding box
prediction, a class-specific bounding-box normalizer and an expected
intersection-over-union are proposed. In the experiments, the proposed approach
was evaluated by a testing set with 1200 images using CDR error and score
for CDR measurement and dice coefficient for image segmentation. A grader study
was conducted to compare the performance of the proposed approach with those of
individual graders. The experimental results indicate that the proposed
approach outperforms the state-of-the-art performance obtained from the fully
supervised image segmentation (FSIS) approach using pixel-wise annotation for
CDR measurement. Its performance is also better than those of individual
graders. In addition, the proposed approach gets performance close to the
state-of-the-art obtained from FSIS and the performance of individual graders
for optic cup and disc segmentation. The codes are available at
\url{https://github.com/wangjuan313/CDRNet}.Comment: 18 pages, 7 figures, 8 tables, Multimedia Tools and Application
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Dexmedetomidine post-treatment attenuates cardiac ischaemia/reperfusion injury by inhibiting apoptosis through HIF-1α signalling.
Hypoxia-inducible factor 1α (HIF-1α) plays a critical role in the apoptotic process during cardiac ischaemia/reperfusion (I/R) injury. This study aimed to investigate whether post-treatment with dexmedetomidine (DEX) could protect against I/R-induced cardiac apoptosis in vivo and in vitro via regulating HIF-1α signalling pathway. Rat myocardial I/R was induced by occluding the left anterior descending artery for 30 minutes followed by 6-hours reperfusion, and cardiomyocyte hypoxia/reoxygenation (H/R) was induced by oxygen-glucose deprivation for 6 hours followed by 3-hours reoxygenation. Dexmedetomidine administration at the beginning of reperfusion or reoxygenation attenuated I/R-induced myocardial injury or H/R-induced cell death, alleviated mitochondrial dysfunction, reduced the number of apoptotic cardiomyocytes, inhibited the activation of HIF-1α and modulated the expressions of apoptosis-related proteins including BCL-2, BAX, BNIP3, cleaved caspase-3 and cleaved PARP. Conversely, the HIF-1α prolyl hydroxylase-2 inhibitor IOX2 partly blocked DEX-mediated cardioprotection both in vivo and in vitro. Mechanistically, DEX down-regulated HIF-1α expression at the post-transcriptional level and inhibited the transcriptional activation of the target gene BNIP3. Post-treatment with DEX protects against cardiac I/R injury in vivo and H/R injury in vitro. These effects are, at least in part, mediated via the inhibition of cell apoptosis by targeting HIF-1α signalling
Effects of Vanadium doping on BaFe2As2
We report an investigation of the structural, magnetic and electronic
properties of Ba(Fe(1-x)V(x))2As2 using x-ray, transport, magnetic
susceptibility and neutron scattering measurements. The vanadium substitutions
in Fe sites are possible up to 40\%. Hall effect measurements indicate strong
hole-doping effect through V doping, while no superconductivity is observed in
all samples down to 2K. The antiferromagnetic and structural transition
temperature of BaFe2As2 is gradually suppressed to finite temperature then
vanishes at x=0.245 with the emergence of spin glass behavior, suggesting an
avoided quantum critical point (QCP). Our results demonstrate that the avoided
QCP and spin glass state which were previously reported in the superconducting
phase of Co/Ni-doped BaFe2As2 can also be realized in non-superconducting
Ba(Fe(1-x)V(x))2As2.Comment: 5 pages, 6 figure
Stability analyses of deterministic and stochastic SEIRI epidemic models with nonlinear incidence rates and distributed delay
In this paper, deterministic and stochastic SEIRI epidemic models featuring a distributed latent period and general, unspecified nonlinear incidence and growth rates for the susceptible class are proposed and investigated from a stability viewpoint. By applying Lyapunov–LaSalle invariance principle, we first obtain sufficient conditions for the global stability of equilibria of the deterministic model. On the basis of this result, we subsequently derive sufficient conditions for asymptotic stability of the stochastic model. Finally, numerical simulations are given to illustrate the previously obtained theoretical framework
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