150 research outputs found
ROAD: Reality Oriented Adaptation for Semantic Segmentation of Urban Scenes
Exploiting synthetic data to learn deep models has attracted increasing
attention in recent years. However, the intrinsic domain difference between
synthetic and real images usually causes a significant performance drop when
applying the learned model to real world scenarios. This is mainly due to two
reasons: 1) the model overfits to synthetic images, making the convolutional
filters incompetent to extract informative representation for real images; 2)
there is a distribution difference between synthetic and real data, which is
also known as the domain adaptation problem. To this end, we propose a new
reality oriented adaptation approach for urban scene semantic segmentation by
learning from synthetic data. First, we propose a target guided distillation
approach to learn the real image style, which is achieved by training the
segmentation model to imitate a pretrained real style model using real images.
Second, we further take advantage of the intrinsic spatial structure presented
in urban scene images, and propose a spatial-aware adaptation scheme to
effectively align the distribution of two domains. These two modules can be
readily integrated with existing state-of-the-art semantic segmentation
networks to improve their generalizability when adapting from synthetic to real
urban scenes. We evaluate the proposed method on Cityscapes dataset by adapting
from GTAV and SYNTHIA datasets, where the results demonstrate the effectiveness
of our method.Comment: Add experiments on SYNTHIA, CVPR 2018 camera-ready versio
Domain Adaptive Faster R-CNN for Object Detection in the Wild
Object detection typically assumes that training and test data are drawn from
an identical distribution, which, however, does not always hold in practice.
Such a distribution mismatch will lead to a significant performance drop. In
this work, we aim to improve the cross-domain robustness of object detection.
We tackle the domain shift on two levels: 1) the image-level shift, such as
image style, illumination, etc, and 2) the instance-level shift, such as object
appearance, size, etc. We build our approach based on the recent
state-of-the-art Faster R-CNN model, and design two domain adaptation
components, on image level and instance level, to reduce the domain
discrepancy. The two domain adaptation components are based on H-divergence
theory, and are implemented by learning a domain classifier in adversarial
training manner. The domain classifiers on different levels are further
reinforced with a consistency regularization to learn a domain-invariant region
proposal network (RPN) in the Faster R-CNN model. We evaluate our newly
proposed approach using multiple datasets including Cityscapes, KITTI, SIM10K,
etc. The results demonstrate the effectiveness of our proposed approach for
robust object detection in various domain shift scenarios.Comment: Accepted to CVPR 201
Key criterion for achieving giant recovery strains in polycrystalline Fe-Mn-Si based shape memory alloys
In this study, it is proposed that coarsening austenitic grains is a key criterion for achieving giant recovery strains in polycrystalline Fe-Mn-Si based shape memory alloys. In order to verify the hypothesis, the relationship between recovery strains and austenitic grain-sizes in cast and processed Fe-Mn-Si based shape memory alloys was investigated. The recovery strain of cast Fe-19Mn-5.5Si-9Cr-4.5Ni alloy with the coarse austenitic grains of 652 µm reached 7.7% while the recovery strain of one with the relatively small austenitic grains of 382 µm was only 5.4%. Moreover, a recovery strain of 5.9%, which is the highest previously published value for solution-treated processed Fe-Mn-Si based shape memory alloys, was obtained by coarsening the austenitic grains through only solution treatment at 1483 K for 360 min in a processed Fe-17Mn-5.5Si-9Cr-5.5Ni-0.12C alloy. However, its recovery strain was still 5.9% after thermo-mechanical treatment consisting of 10% tensile strain at room temperature and annealing at 1073 K for 30 min. This happens because annealing twins play a negative role, refining the austenitic grains, limiting the recovery strains to below 6%. In summary, coarse austenitic grains enable the achievement large recovery strains by two mechanisms. Firstly, the grains are bigger, and consequently there are fewer grain boundaries, and thus their suppressive effects of grain boundaries on stress-induced ε martensitic transformation is reduced. Secondly, coarse austenitic grains are advantageous to introduce ε martensite with single orientation and reduce the collisions of different martensite colonies, especially when the deformation strain is large. As such, the ceiling of recovery strains is dependent on the austenitic grain-sizes
BPLLDA: Predicting lncRNA-Disease Associations Based on Simple Paths With Limited Lengths in a Heterogeneous Network
In recent years, it has been increasingly clear that long noncoding RNAs (lncRNAs) play critical roles in many biological processes associated with human diseases. Inferring potential lncRNA-disease associations is essential to reveal the secrets behind diseases, develop novel drugs, and optimize personalized treatments. However, biological experiments to validate lncRNA-disease associations are very time-consuming and costly. Thus, it is critical to develop effective computational models. In this study, we have proposed a method called BPLLDA to predict lncRNA-disease associations based on paths of fixed lengths in a heterogeneous lncRNA-disease association network. Specifically, BPLLDA first constructs a heterogeneous lncRNA-disease network by integrating the lncRNA-disease association network, the lncRNA functional similarity network, and the disease semantic similarity network. It then infers the probability of an lncRNA-disease association based on paths connecting them and their lengths in the network. Compared to existing methods, BPLLDA has a few advantages, including not demanding negative samples and the ability to predict associations related to novel lncRNAs or novel diseases. BPLLDA was applied to a canonical lncRNA-disease association database called LncRNADisease, together with two popular methods LRLSLDA and GrwLDA. The leave-one-out cross-validation areas under the receiver operating characteristic curve of BPLLDA are 0.87117, 0.82403, and 0.78528, respectively, for predicting overall associations, associations related to novel lncRNAs, and associations related to novel diseases, higher than those of the two compared methods. In addition, cervical cancer, glioma, and non-small-cell lung cancer were selected as case studies, for which the predicted top five lncRNA-disease associations were verified by recently published literature. In summary, BPLLDA exhibits good performances in predicting novel lncRNA-disease associations and associations related to novel lncRNAs and diseases. It may contribute to the understanding of lncRNA-associated diseases like certain cancers
A universal programmable Gaussian Boson Sampler for drug discovery
Gaussian Boson Sampling (GBS) exhibits a unique ability to solve graph
problems, such as finding cliques in complex graphs. It is noteworthy that many
drug discovery tasks can be viewed as the clique-finding process, making them
potentially suitable for quantum computation. However, to perform these tasks
in their quantum-enhanced form, a large-scale quantum hardware with universal
programmability is essential, which is yet to be achieved even with the most
advanced GBS devices. Here, we construct a time-bin encoded GBS photonic
quantum processor that is universal, programmable, and software-scalable. Our
processor features freely adjustable squeezing parameters and can implement
arbitrary unitary operations with a programmable interferometer. Using our
processor, we have demonstrated the clique-finding task in a 32-node graph,
where we found the maximum weighted clique with approximately twice the
probability of success compared to classical sampling. Furthermore, a
multifunctional quantum pharmaceutical platform is developed. This GBS
processor is successfully used to execute two different drug discovery methods,
namely molecular docking and RNA folding prediction. Our work achieves the
state-of-the-art in GBS circuitry with its distinctive universal and
programmable architecture which advances GBS towards real-world applications.Comment: 10 pages, 5 figure
IL-21 promotes myocardial ischaemia/reperfusion injury through the modulation of neutrophil infiltration.
BACKGROUND AND PURPOSE: The immune system plays an important role in driving the acute inflammatory response following myocardial ischaemia/reperfusion injury (MIRI). IL-21 is a pleiotropic cytokine with multiple immunomodulatory effects, but its role in MIRI is not known. EXPERIMENTAL APPROACH: Myocardial injury, neutrophil infiltration and the expression of neutrophil chemokines KC (CXCL1) and MIP-2 (CXCL2) were studied in a mouse model of MIRI. Effects of IL-21 on the expression of KC and MIP-2 in neonatal mouse cardiomyocytes (CMs) and cardiac fibroblasts (CFs) were determined by real-time PCR and ELISA. The signalling mechanisms underlying these effects were explored by western blot analysis. KEY RESULTS: IL-21 was elevated within the acute phase of murine MIRI. Neutralization of IL-21 attenuated myocardial injury, as illustrated by reduced infarct size, decreased cardiac troponin T levels and improved cardiac function, whereas exogenous IL-21 administration exerted opposite effects. IL-21 increased the infiltration of neutrophils and increased the expression of KC and MIP-2 in myocardial tissue following MIRI. Moreover, neutrophil depletion attenuated the IL-21-induced myocardial injury. Mechanistically, IL-21 increased the production of KC and MIP-2 in neonatal CMs and CFs, and enhanced neutrophil migration, as revealed by the migration assay. Furthermore, we demonstrated that this IL-21-mediated increase in chemokine expression involved the activation of Akt/NF-κB signalling in CMs and p38 MAPK/NF-κB signalling in CFs. CONCLUSIONS AND IMPLICATIONS: Our data provide novel evidence that IL-21 plays a pathogenic role in MIRI, most likely by promoting cardiac neutrophil infiltration. Therefore, targeting IL-21 may have therapeutic potential as a treatment for MIRI. LINKED ARTICLES: This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc
Quantitative analysis and comparison of 3D morphology between viable and apoptotic MCF-7 breast cancer cells and characterization of nuclear fragmentation
Morphological changes in apoptotic cells provide essential markers for defining and detection
of apoptosis as a fundamental mechanism of cell death. Among these changes, the
nuclear fragmentation and condensation have been regarded as the important markers but
quantitative characterization of these changes is yet to be achieved. We have acquired confocal
image stacks of 206 viable and apoptotic MCF-7 cells stained by three fluorescent
dyes. Three-dimensional (3D) parameters were extracted to quantify and compare their differences
in morphology. To analyze nuclear fragmentation, a new method has been developed
to determine clustering of nuclear voxels in the reconstructed cells due to fluorescence
intensity changes in nuclei of apoptotic cells. The results of these studies reveal that the 3D
morphological changes in cytoplasm and nuclear membranes in apoptotic cells provide sensitive
targets for label-free detection and staging of apoptosis. Furthermore, the clustering
analysis and morphological data on nuclear fragmentation are highly useful for derivation of
optical cell models and simulation of diffraction images to investigate light scattering by
early apoptotic cells, which can lead to future development of label-free and rapid methods
of apoptosis assay based on cell morphology.Open Access Fundin
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