140 research outputs found
Differentiable Topology-Preserved Distance Transform for Pulmonary Airway Segmentation
Detailed pulmonary airway segmentation is a clinically important task for
endobronchial intervention and treatment of peripheral located lung cancer
lesions. Convolutional Neural Networks (CNNs) are promising tools for medical
image analysis but have been performing poorly for cases when existing a
significant imbalanced feature distribution, which is true for the airway data
as the trachea and principal bronchi dominate most of the voxels whereas the
lobar bronchi and distal segmental bronchi occupy a small proportion. In this
paper, we propose a Differentiable Topology-Preserved Distance Transform
(DTPDT) framework to improve the performance of airway segmentation. A
Topology-Preserved Surrogate (TPS) learning strategy is first proposed to
balance the training progress within-class distribution. Furthermore, a
Convolutional Distance Transform (CDT) is designed to identify the breakage
phenomenon with superior sensitivity and minimize the variation of the distance
map between the predictionand ground-truth. The proposed method is validated
with the publically available reference airway segmentation datasets. The
detected rate of branch and length on public EXACT'09 and BAS datasets are
82.1%/79.6% and 96.5%/91.5% respectively, demonstrating the reliability and
efficiency of the method in terms of improving the topology completeness of the
segmentation performance while maintaining the overall topology accuracy.Comment: 10 page
MicroRNA-542 suppressed the proliferation of human glioma cells by targeting talin-2 (TLN2)
Purpose: To investigate the effect of miR-542 in the development of human glioma.
Methods: The expressions of miR-542 and TLN2 in glioma cells and normal human astrocytes were determined using qRT-PCR, while MTT and colony formation assays were used to determine cell proliferation. Western blotting was used to determine protein expression.
Results: It was revealed that miR-542 was significantly downregulated in glioma cells. Overexpression of miR-542 inhibited the proliferation and clonogenicity of glioma cells via induction of apoptosis. The percentage of apoptotic U87 cells increased from 5.32 in control to 26.76 upon miR-542 overexpression. Moreover, TLN2 was identified as the functional regulatory target of miR542 in glioma. The expression of TLN2 was markedly upregulated in human glioma cells. However, overexpression of miR-542 suppressed TLN2 expression. Silencing of TLN2 mimicked the tumor-suppressive effects of miR-542 in glioma cells, but this effect was blocked by TLN2 over-expression.
Conclusion: These results suggest that miR-542 exerted glioma-suppressive effect, with TLN2 as its functional regulatory target.
Keywords: Glioma; Proliferation; Micro-RNA; Tumorigenesis; MiR-542; Apoptosis; Prognosis; talin-2; Oncogen
Climatology of aerosol optical properties and black carbon mass absorption cross section at a remote high-altitude site in the western Mediterranean Basin
Aerosol light scattering (σ<sub>sp</sub>), backscattering
(σ<sub>bsp</sub>) and absorption (σ<sub>ap</sub>)
were measured at Montsec (MSC; 42°3' N, 0°44' E, 1570 m a.s.l.), a remote
high-altitude site in the western Mediterranean Basin. Mean (±SD)
σ<sub>sp</sub>, σ<sub>bsp</sub> and σ<sub>ap</sub> were
18.9 ± 20.8, 2.6 ± 2.8 and 1.5 ± 1.4 Mm<sup>−1</sup>,
respectively at 635 nm during the period under study (June 2011–June 2013). Mean
values of single-scattering albedo (SSA, 635 nm), the scattering
Ångström exponent (SAE, 450–635 nm), backscatter-to-scatter ratio
(<i>B</i> / <i>S</i>, 635 nm), asymmetry parameter (<i>g</i>, 635 nm), black carbon mass absorption
cross section (MAC, 637 nm) and PM<sub>2.5</sub> mass scattering cross section
(MSCS, 635 nm) were 0.92 ± 0.03, 1.56 ± 0.88, 0.16 ± 0.09,
0.53 ± 0.16, 10.9 ± 3.5 m<sup>2</sup> g<sup>−1</sup> and
2.5 ± 1.3 m<sup>2</sup> g<sup>−1</sup>,
respectively. The scattering measurements performed at MSC were in the
medium/upper range of values reported by Andrews et al. (2011) for other
mountaintop sites in Europe due to the frequent regional recirculation
scenarios (SREG) and Saharan dust episodes (NAF) occurring mostly in
spring/summer and causing the presence of polluted layers at the MSC
altitude. However, the development of upslope winds and the possible
presence of planetary boundary layer air at MSC altitude in summer may also
have contributed to the high scattering observed. Under these summer
conditions no clear diurnal cycles were observed for the measured extensive
aerosol optical properties (σ<sub>sp</sub>, σ<sub>bsp</sub>
and σ<sub>ap</sub>). Conversely, low σ<sub>sp</sub> and σ<sub>ap</sub> at MSC were
measured during Atlantic advections (AA) and winter regional anticyclonic
episodes (WREG) typically observed during the cold season in the western
Mediterranean. Therefore, a season-dependent decrease in the magnitude of
aerosol extensive properties was observed when MSC was in the free
troposphere, with the highest free-troposphere vs. all-data difference observed in winter and the lowest
in spring/summer. The location of MSC station allowed for a reliable
characterization of aerosols as a function of the main synoptic meteorological
patterns. The SAE was the lowest during NAF and showed an inverse
correlation with the outbreak intensity, indicating a progressive shift
toward larger particles. Moreover, the strength of NAF episodes in the
region led to a slope of the scattering vs. absorption relationship among the
lowest reported for other mountaintop sites worldwide, indicating that MSC
was dominated by dust aerosols at high aerosol loading. As a consequence,
SSA showed a nearly monotonic increase with increasing particle
concentration and scattering. The SAE was the highest during SREG, indicating
the presence of polluted layers dominated by smaller particles.
Correspondingly, the asymmetry parameter was lower under SREG compared with
NAF. The MAC and MSCS were significantly higher during NAF and SREG compared
to AA and WREG, indicating an increase of absorption and scattering
efficiencies associated with the summer polluted scenarios. The optical
measurements performed at the MSC remote site were compared with those
simultaneously performed at a regional background station in the western
Mediterranean Basin located at around 700 m a.s.l. upstream of the MSC station
Tuning the Magnetism in Ultrathin CrxTey Films by Lattice Dimensionality
Two-dimensional (2D) magnetic transition metal compounds with atomic
thickness exhibit intriguing physics in fundamental research and great
potential for device applications. Understanding the correlations between their
macrosopic magnetic properties and the dimensionality of microscopic magnetic
exchange interactions are valuable for the designing and applications of 2D
magnetic crystals. Here, using spin-polarized scanning tunneling microscopy,
magnetization and magneto-transport measurements, we identify the
zigzag-antiferromagnetism in monolayer CrTe2, incipient ferromagnetism in
bilayer CrTe2, and robust ferromagnetism in bilayer Cr3Te4 films. Our density
functional theory calculations unravel that the magnetic ordering in ultrathin
CrTe2 is sensitive to the lattice parameters, while robust ferromagnetism with
large perpendicular magnetic anisotropy in Cr3Te4 is stabilized through its
anisotropic 3D magnetic exchange interactions
CQARank: Jointly Model Topics and Expertise in Community Question Answering
Community Question Answering (CQA) websites, where people share expertise on open platforms, have become large repositories of valuable knowledge. To bring the best value out of these knowledge repositories, it is critically important for CQA services to know how to find the right experts, retrieve archived similar questions and recommend best answers to new questions. To tackle this cluster of closely related problems in a principled approach, we proposed Topic Expertise Model (TEM), a novel probabilistic generative model with GMM hybrid, to jointly model topics and expertise by integrating textual content model and link structure analysis. Based on TEM results, we proposed CQARank to measure user interests and expertise score under different topics. Leveraging the question answering history based on long-term community reviews and voting, our method could find experts with both similar topical preference and high topical expertise. Experiments carried out on Stack Overflow data, the largest CQA focused on computer programming, show that our method achieves significant improvement over existing methods on multiple metrics. Copyright is held by the owner/author(s).EI
Self-Reference Emerges Earlier than Emotion during an Implicit Self-Referential Emotion Processing Task: Event-Related Potential Evidence
Self-referential emotion refers to the process of evaluating emotional stimuli with respect to the self. Processes indicative of a self-positivity bias are reflected in electroencephalogram (EEG) signals at ~400 ms when the task does not require a discrimination of self from other. However, when distinguishing between self-referential and other-referential emotions is required, previous studies have shown inconsistent temporal dynamics of EEG signals in slightly different tasks. Based on the observation of early self–other discrimination, we hypothesized that self would be rapidly activated in the early stage to modulate emotional processing in the late stage during an implicit self-referential emotion. To test this hypothesis, we employed an implicit task in which participants were asked to judge the order of Chinese characters of trait adjectives preceded by a self (“I”) or other pronoun (“He” or “She”). This study aimed to explore the difference of social-related emotional evaluation from self-reference; the other pronoun was not defined to a specific person, rather it referred to the general concept. Sixteen healthy Chinese subjects participated in the experiment. Event-related potentials (ERPs) showed that there were self-other discrimination effects in the N1 (80–110 ms) and P1 (170–200 ms) components in the anterior brain. The emotional valence was discriminated in the later component of N2 (220–250 ms). The interaction between self-reference and emotional valence occurred during the late positive potential (LPP; 400–500 ms). Moreover, there was a positive correlation between response time (RT) and N1 in the self-reference condition based on the positive-negative contrast, suggesting a modulatory effect of the self-positivity bias. The results indicate that self-reference emerges earlier than emotion and then combines with emotional processing in an implicit task. The findings extend the view that the self plays a highly integrated and modulated role in self-referential emotion processing
Cyclization reaction of amines with dialkyl carbonates to yield 1,3-oxazinan-2-ones
A number of six-membered cyclic carbamates (oxazinanones) were synthesized from the reaction of a primary amine or hydrazine with a dicarbonate derivative of 1,3-diols in a one-pot reaction, in good yield, short time span, and in the absence of a solvent. The reaction proceeds in two steps: an intermolecular reaction to give a linear intermediate and an intramolecular cyclization to yield the cyclic carbamate. This is the first example of a carbonate reacting selectively and sequentially, firstly at the carbonyl center to form a linear carbamate and then as a leaving group to yield a cyclic carbamate
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