Supervised deep networks have achieved promising performance on image denoising, by learning image priors and noise statistics on plenty pairs of noisy and clean images. Unsupervised denoising ...networks are trained with only noisy images. However, for an unseen corrupted image, both supervised and unsupervised networks ignore either its particular image prior, the noise statistics, or both. That is, the networks learned from external images inherently suffer from a domain gap problem: the image priors and noise statistics are very different between the training and test images. This problem becomes more clear when dealing with the signal dependent realistic noise. To circumvent this problem, in this work, we propose a novel "Noisy-As-Clean" (NAC) strategy of training self-supervised denoising networks. Specifically, the corrupted test image is directly taken as the "clean" target, while the inputs are synthetic images consisted of this corrupted image and a second yet similar corruption. A simple but useful observation on our NAC is: as long as the noise is weak, it is feasible to learn a self-supervised network only with the corrupted image, approximating the optimal parameters of a supervised network learned with pairs of noisy and clean images. Experiments on synthetic and realistic noise removal demonstrate that, the DnCNN and ResNet networks trained with our self-supervised NAC strategy achieve comparable or better performance than the original ones and previous supervised/unsupervised/self-supervised networks. The code is publicly available at https://github.com/csjunxu/Noisy-As-Clean .
Upper gastrointestinal cancers (including oesophageal cancer and gastric cancer) are the most common cancers worldwide. Artificial intelligence platforms using deep learning algorithms have made ...remarkable progress in medical imaging but their application in upper gastrointestinal cancers has been limited. We aimed to develop and validate the Gastrointestinal Artificial Intelligence Diagnostic System (GRAIDS) for the diagnosis of upper gastrointestinal cancers through analysis of imaging data from clinical endoscopies.
This multicentre, case-control, diagnostic study was done in six hospitals of different tiers (ie, municipal, provincial, and national) in China. The images of consecutive participants, aged 18 years or older, who had not had a previous endoscopy were retrieved from all participating hospitals. All patients with upper gastrointestinal cancer lesions (including oesophageal cancer and gastric cancer) that were histologically proven malignancies were eligible for this study. Only images with standard white light were deemed eligible. The images from Sun Yat-sen University Cancer Center were randomly assigned (8:1:1) to the training and intrinsic verification datasets for developing GRAIDS, and the internal validation dataset for evaluating the performance of GRAIDS. Its diagnostic performance was evaluated using an internal and prospective validation set from Sun Yat-sen University Cancer Center (a national hospital) and additional external validation sets from five primary care hospitals. The performance of GRAIDS was also compared with endoscopists with three degrees of expertise: expert, competent, and trainee. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of GRAIDS and endoscopists for the identification of cancerous lesions were evaluated by calculating the 95% CIs using the Clopper-Pearson method.
1 036 496 endoscopy images from 84 424 individuals were used to develop and test GRAIDS. The diagnostic accuracy in identifying upper gastrointestinal cancers was 0·955 (95% CI 0·952–0·957) in the internal validation set, 0·927 (0·925–0·929) in the prospective set, and ranged from 0·915 (0·913–0·917) to 0·977 (0·977–0·978) in the five external validation sets. GRAIDS achieved diagnostic sensitivity similar to that of the expert endoscopist (0·942 95% CI 0·924–0·957 vs 0·945 0·927–0·959; p=0·692) and superior sensitivity compared with competent (0·858 0·832–0·880, p<0·0001) and trainee (0·722 0·691–0·752, p<0·0001) endoscopists. The positive predictive value was 0·814 (95% CI 0·788–0·838) for GRAIDS, 0·932 (0·913–0·948) for the expert endoscopist, 0·974 (0·960–0·984) for the competent endoscopist, and 0·824 (0·795–0·850) for the trainee endoscopist. The negative predictive value was 0·978 (95% CI 0·971–0·984) for GRAIDS, 0·980 (0·974–0·985) for the expert endoscopist, 0·951 (0·942–0·959) for the competent endoscopist, and 0·904 (0·893–0·916) for the trainee endoscopist.
GRAIDS achieved high diagnostic accuracy in detecting upper gastrointestinal cancers, with sensitivity similar to that of expert endoscopists and was superior to that of non-expert endoscopists. This system could assist community-based hospitals in improving their effectiveness in upper gastrointestinal cancer diagnoses.
The National Key R&D Program of China, the Natural Science Foundation of Guangdong Province, the Science and Technology Program of Guangdong, the Science and Technology Program of Guangzhou, and the Fundamental Research Funds for the Central Universities.
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•Polysaccharide isolated from Hericium erinaceus fruiting body exerted gastroprotective activity.•The polysaccharide had antioxidant activities in vitro.•Potentials of the ...polysaccharide in preventing duodenum ulcer and promoting colonic health of rat were observed.•The mechanism of gastroprotective activity might involve its antisecretory, antioxidant, anti-inflammatory and increments of defensive factors.
The gastroprotective activity of Hericium erinaceus polysaccharide was investigated in rats. The antioxidant activities were also evaluated. Pre-treatment of polysaccharide could reduce ethanol-induced gastric mucosal lesion and pylorus ligation-induced gastric ulcer. The polysaccharide exhibited scavenging activities of 1, 1-diphenyl-2-picryl-hydrozyl and hydroxyl radicals, and ferrous ion-chelating ability. In the pylorus ligation-induced model, gastric secretions (volume of gastric juice, gastric acid, pepsin and mucus) of ulcer rats administrated with polysaccharide were regulated. Levels of tumor necrosis factor-α and interleukins-1β in serum, and myeloperoxidase activity of gastric tissue were reduced, while antioxidant status of gastric tissue was improved. Defensive factors (nitric oxide, prostaglandin E2, epidermal growth factor) in gastric tissue were increased. These results indicate that Hericium erinaceus polysaccharide possess gastroprotective activity, and the possible mechanisms are related to its regulations of gastric secretions, improvements of anti-inflammatory and antioxidant status, as well as increments of defensive factors releases.
Salient object detection, which simulates human visual perception in locating the most significant object(s) in a scene, has been widely applied to various computer vision tasks. Now, the advent of ...depth sensors means that depth maps can easily be captured; this additional spatial information can boost the performance of salient object detection. Although various RGB-D based salient object detection models with promising performance have been proposed over the past several years, an in-depth understanding of these models and the challenges in this field remains lacking. In this paper, we provide a comprehensive survey of RGB-D based salient object detection models from various perspectives, and review related benchmark datasets in detail. Further, as light fields can also provide depth maps, we review salient object detection models and popular benchmark datasets from this domain too. Moreover, to investigate the ability of existing models to detect salient objects, we have carried out a comprehensive attribute-based evaluation of several representative RGB-D based salient object detection models. Finally, we discuss several challenges and open directions of RGB-D based salient object detection for future research. All collected models, benchmark datasets, datasets constructed for attribute-based evaluation, and related code are publicly available at
https://github.com/taozh2017/RGBD-SODsurvey
.
Abstract
We perform a hierarchical Bayesian inference to investigate the population properties of the coalescing compact binaries involving at least one neutron star (NS). With the current ...gravitational-wave (GW) observation data, we can rule out none of the double Gaussian, single Gaussian, and uniform NS mass distribution models, though a specific double Gaussian model inferred from the Galactic NSs is found to be slightly more preferred. The mass distribution of black holes (BHs) in the neutron star–black hole (NSBH) population is found to be similar to that in the Galactic X-ray binaries. Additionally, the ratio of the merger rate densities between NSBHs and BNSs is estimated to be ∼3:7. The spin properties of the binaries, though constrained relatively poorly, play a nontrivial role in reconstructing the mass distribution of NSs and BHs. We find that a perfectly aligned spin distribution can be ruled out, while a purely isotropic distribution of spin orientation is still allowed. To evaluate the feasibility of reliably determining the population properties of NSs in the coalescing compact binaries with upcoming GW observations, we perform simulations with a mock population. We find that with 100 detections (including BNSs and NSBHs) the mass distribution of NSs can be well determined, and the fraction of BNSs can also be accurately estimated.
Continuous‐wave (CW) room‐temperature (RT) laser operation with low energy consumption is an ultimate goal for electrically driven lasers. A monolithically integrated perovskite laser in a chip‐level ...fiber scheme is ideal. However, because of the well‐recognized air and thermal instabilities of perovskites, laser action in a perovskite has mostly been limited to either pulsed or cryogenic‐temperature operations. Most CW laser operations at RT have had poor durability. Here, crystal fibers that have robust and high‐heat‐load nature are shown to be the key to enabling the first demonstration of ultralow‐threshold CW RT laser action in a compact, monolithic, and inexpensive crystal fiber/nanoperovskite hybrid architecture that is directly pumped with a 405 nm diode laser. Purcell‐enhanced light–matter coupling between the atomically smooth fiber microcavity and the perovskite nanocrystallites gain medium enables a high Q (≈1500) and a high β (0.31). This 762 nm laser outperforms previously reported structures with a record‐low threshold of 132 nW and an optical‐to‐optical slope conversion efficiency of 2.93%, and it delivers a stable output for CW and RT operation. These results represent a significant advancement toward monolithic all‐optical integration.
Purcell‐enhanced light–matter coupling between an atomically smooth fiber microcavity and perovskite gain nanocrystallites enables a high Q (≈1500) and a high β (0.31), outperforming previously reported structures with a 132 nW record‐low threshold. This is thought to be the first demonstration of monolithic integration of a perovskite laser into a compact and inexpensive fiber platform.
Background
This study aimed to explore the prognostic utility of the preoperative platelet‐to‐albumin ratio (PAR) among patients with oral cavity squamous cell carcinoma (OSCC).
Methods
We ...retrospectively reviewed of 355 patients with surgically‐treated OSCC between 2008 and 2017. The optimal PAR cutoff for patient stratification was determined through X‐tile analysis. Prognostic variables for disease‐free survival (DFS) and overall survival (OS) were identified using Cox proportional hazards models. We developed a PAR‐based nomogram to predict personalized OS.
Results
We determined the optimal PAR cutoff to be 7.45. A PAR of ≥7.45 was an independent negative prognostic factor for DFS and OS (hazard ratio = 1.748 and 2.386; p = 0.005 and p < 0.001, respectively). The developed nomogram demonstrates the practical utility of PAR and accurately predicts personalized OS.
Conclusions
The preoperative PAR is a promising and cost‐effective prognostic biomarker for patients with surgically‐treated OSCC; the PAR‐based nanogram accurately predicts OS for such patients.
Cu2O-based composites for photocatalysis have been extensively explored owing to their promising application in solving environmental and energy problems. At present, the research on photocatalysis ...is focused on improving the photocatalytic performance of materials. It has been reported that adjusting the morphology and size of Cu2O can effectively improve its photocatalytic property. However, photocorrosion is still an inevitable problem, which hinders the application of Cu2O in photocatalysis. The strategies of constructing heterogeneous nanostructures and ion doping can significantly improve the light stability, light absorption capacity and separation efficiency of electron–hole pairs. Cu2O-based composites exhibit superior performances in degrading organic matter, producing hydrogen, reducing CO2 and sterilization. Therefore, the construction of multi-materials will be one of the future directions in their photocatalytic application. This review summarizes the recent strategies for enhancing the photocatalytic activity of Cu2O by analyzing different Cu2O-based photocatalysts, and the charge transfer pathway is further discussed in detail. Finally, several opportunities and challenges in the field of photocatalysis are illustrated.
Concealed Object Detection Fan, Deng-Ping; Ji, Ge-Peng; Cheng, Ming-Ming ...
IEEE transactions on pattern analysis and machine intelligence,
10/2022, Letnik:
44, Številka:
10
Journal Article
Recenzirano
Odprti dostop
We present the first systematic study on concealed object detection (COD), which aims to identify objects that are visually embedded in their background. The high intrinsic similarities between the ...concealed objects and their background make COD far more challenging than traditional object detection/segmentation. To better understand this task, we collect a large-scale dataset, called COD10K , which consists of 10,000 images covering concealed objects in diverse real-world scenarios from 78 object categories. Further, we provide rich annotations including object categories, object boundaries, challenging attributes, object-level labels, and instance-level annotations. Our COD10K is the largest COD dataset to date, with the richest annotations, which enables comprehensive concealed object understanding and can even be used to help progress several other vision tasks, such as detection, segmentation, classification etc . Motivated by how animals hunt in the wild, we also design a simple but strong baseline for COD, termed the Search Identification Network ( SINet ). Without any bells and whistles, SINet outperforms twelve cutting-edge baselines on all datasets tested, making them robust, general architectures that could serve as catalysts for future research in COD. Finally, we provide some interesting findings, and highlight several potential applications and future directions. To spark research in this new field, our code, dataset, and online demo are available at our project page: http://mmcheng.net/cod .
The heterotrimetallic complexes FeMFe(dpa)4Cl2 (M=Ni (1), Pd (2), and Pt (3); dpa−=dipyridylamido) featuring two high‐spin iron centers linked by Group 10 metals were synthesized and their physical ...properties were investigated. Oxidation of 1–3 with suitable oxidants in CH2Cl2 solution yielded the mixed‐valent species 1+/2+–3+/2+. The solution properties of 10/+/2+–30/+/2+ were characterized by 1H NMR and UV/Vis/NIR spectroscopy as well as spectroelectrochemisty. The mixed‐valent states of 1+–3+ obtained by electrochemical or chemical oxidation are classified as class II valence delocalization. The solid‐state structures of 1–3, 1+, 3+, and 12+ were determined by single‐crystal X‐ray diffraction analysis, exhibiting a linear metal framework with an approximate D4 symmetry. The spin states and magnetic properties were studied by using SQUID magnetometry, EPR and Mössbauer spectroscopy, and DFT calculations. Antiferromagnetic interactions between terminal high‐spin iron centers are present within 10/+/2+–30/+/2+ and the |J| values increase with the central metal ion changing from Ni to Pt. The DFT calculations reproduce the antiferromagnetic coupling and ascribe it to a σ‐type exchange pathway. The substitution of the central metal not only influences the spin–spin interactions but also the degree of electronic delocalization between the terminal iron sites along the Fe‐M‐Fe chains.
Localized…or delocalized? Heterotrimetallic string complexes FeMFe(dpa)4Cl2 (M=Ni, Pd, and Pt) and their one‐ and two‐electron‐oxidized congeners were synthesized and investigated. One‐electron oxidation generated mixed‐valent diiron sites within the metal framework. The magnetic susceptibility and Mössbauer spectroscopic data revealed that the spin–spin interactions and electron delocalization can be modulated by changing the central metal ion (see figure).
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