ConCL: Concept Contrastive Learning for Dense Prediction Pre-training in Pathology Images

Detectingandsegmentingobjectswithinwholeslideimagesis essential in computational pathology workflow. Self-supervised learning (SSL) is appealing to such annotation-heavy tasks. Despite the extensive benchmarks in natural images for dense tasks, such studies are, unfortunately, absent in current works for pathology. Our paper intends to narrow this gap. We first benchmark representative SSL methods for dense prediction tasks in pathology images. Then, we propose concept contrastive learning (ConCL), an SSL framework for dense pre-training. We explore how ConCL performs with concepts provided by different sources and end up with proposing a simple dependency-free concept generating method that does not rely on external segmentation algorithms or saliency detection models. Extensive experiments demonstrate the superiority of ConCL over previous state-of-the-art SSL methods across different settings. Along our exploration, we distll several important and intriguing components contributing to the success of dense pre-training for pathology images. We hope this work could provide useful data points and encourage the community to conduct ConCL pre-training for problems of interest. Code is available.Comment: Accepted as an ECCV 2022 paper. Code is available at https://github.com/Jiawei-Yang/ConCL or https://github.com/TencentAILabHealthcare/ConC

Survey of facial masks using behaviour during COVID-19 outbreak

Wearing facial masks has been indicated as an effective way to reduce the risk of COVID-19 transmission among people. To get a deeper understanding of the habit of using face masks in normal life during COVID-19 outbreak and seek ways to solve the problems of mask using, we conducted a large-scale survey in China through online questionnaires. Totally 1004 respondents, including community outreach workers, non-healthcare professionals, retired people, and students participated in this study. Detailed information regarding the types of masks that people usually use, the habit of changing masks, the methods of mask cleaning, and the attitude toward reusing masks and their potential impact on the environment were collected and analyzed. Results show that more than 98% of people in China used masks during the pandemic, and the types of masks using and frequency of masks changing/reuse varied between different people. Moreover, most of the respondents had a healthy mask-changing habit for preventing the spread of COVID-19 and worried about the safety of mask reusing. The study would help enhance public awareness and develop policies for a better habit in face of the pandemic

Effect of Cryomilling on Microstructure and Mechanical Properties of 7050 Aluminum Alloy

The 7050 aluminum alloy samples were prepared from as-atomized 7050 aluminum alloy powder through cryomilling, hot isostatic pressing, hot extrusion and T6 heat treatment. The influence of cryomilling on morphology, grain size and microscopic strain of aluminum alloy powder were analyzed by SEM and XRD. The influence of cryomilling on microstructure and mechanical property of the sample after heat treatment was analyzed by OM, EBSD, TEM, XRD, microhardness and tensile test. The results show that cryomilling can effectively refine the grain size of the material and increase the number of nano-precipitates in the matrix. Compared to the as-atomized powder, the mechanical properties of the 7050 aluminum alloy sample prepared by cryomillied powder are obviously improved

Integrated modeling of the gradient structure evolution during surface mechanical grinding treatment: Formation mechanism and mechanical properties

Gradient nanostructured materials are regarded as a promising class of architectures with tunable mechanical properties, primarily dependent on the optimization of well-controlled fabrication parameters. In this paper, a microvariable-based constitutive model is incorporated into an integrated finite analysis technique. This approach correlates the fabrication parameters of surface mechanical grinding treatment (SMGT) with the corresponding measured mechanical properties of gradient structured (GS) materials, quantifying the relationship between process parameters, microstructure, and mechanical properties. Through theoretical prediction and experimental verification, it is observed that grain refinement, mechanical strength, and surface hardness are enhanced by increasing processing times and reducing path spacing. The yield stress of the fabricated GS material ranges from 126.8 MPa to 162.2 MPa, an increase of above 2.5 times compared to the original material, with a slight decrease in uniform elongation by a factor of 25.8 %, indicative of an excellent strength-ductility trade-off. The underlying mechanism for improved strength-ductility synergy is discussed, focusing on the importance of the tunable spatial distribution of grain size. This work sheds light on the potential application of gradient nanograined structures at an industrial scale and advances the fundamental understanding of strengthening mechanisms in gradient nanostructures

Overcoming strength–ductility trade-off in shape–performance integrated fabrication by incremental sheet forming

The integrated fabrication of accurate forming shapes and micro–macro properties of metal components have promoted carbon neutrality in industrial manufacturing. We found that the multi-stage incremental sheet forming (MISF) process can achieve shape–performance integrated fabrication of thin-walled parts. However, the performance-influencing mechanism of the MISF approach remains unknown, and the methods for mechanical property prediction have received little attention. Therefore, MISF strategies were investigated for a square copper part through experiments, microstructural analysis, and theoretical predictions. The parts formed with different strategies had the same shape, but their strength–ductility synergy increased with the number of stages. In addition, the MISF-produced copper demonstrated an outstanding strength–ductility trade-off, where the yield stress with the optimized strategy was improved to 231.7 MPa, an increase of over 2.6 times compared with that of the raw material, with a uniform elongation of 20.5 %. A microstructural analysis was performed to investigate the material reinforcement mechanism attributable to dislocation accumulation, which decreased with an increasing number of stages. Based on the deformation procedures and microstructure evolution, an efficient theoretical model of the MISF mechanical properties was proposed for the first time using a dislocation-based constitutive function, where the effectiveness was improved by considering the back stress. This work demonstrates the practicality of the shape–performance integrated fabrication of thin-walled parts and sheds light on the application of the MISF technique

Mortality and Associated Risk Factors in Dialysis Patients with Cardiovascular Disease

Background/Aims: Although dialysis patients have a higher risk of morbidity and mortality related to cardiovascular disease (CVD) than the general population, the mortality and associated risk factors in Asian dialysis patients with CVD have not been well examined. Methods: In this prospective cohort study, mortality and risk factors were investigated in 591 dialysis patients who were recruited from two dialysis centers from May 1, 2009 to May 1, 2014. The Cox proportional hazards regression assessed adjusted differences in mortality risk. A multivariate analysis was also performed, comparing the CVD and non-CVD groups. Results: A total of 591 patients were enrolled in this study (mean age, 52.05 ± 16.46 years [SD]; 61.8% men; 20.8% with CVD), with a median follow-up of 21.9 (maximum, 72) months. The cumulative hazard of mortality was significantly higher in CVD patients (hazard ratio [HR], 1.835; 95% confidence interval [CI], 1.023-3.293; P=0.042) than in their non-CVD counterparts after adjusting for various confounders. On multivariate Cox analysis, stroke (HR, 4.574; 95% CI, 2.149-9.736; PConclusion: All-cause mortality was significantly higher in the CVD group than in the non-CVD group. Stroke is an independent risk factor for all-cause mortality in dialysis patients with CVD. These findings warrant further studies into preventive and interventional strategies