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Attention has become more attractive in person reidentification (ReID) as it is capable of biasing the allocation of available resources towards the most informative parts of an input signal. However, state-of-the-art works concentrate only on coarse or first-order attention design, e.g. spatial and channels attention, while rarely exploring higher-order attention mechanism. We take a step towards addressing this problem. In this paper, we first propose the High-Order Attention (HOA) module to model and utilize the complex and high-order statistics information in attention mechanism, so as to capture the subtle differences among pedestrians and to produce the discriminative attention proposals. Then, rethinking person ReID as a zero-shot learning problem, we propose the Mixed High-Order Attention Network (MHN) to further enhance the discrimination and richness of attention knowledge in an explicit manner. Extensive experiments have been conducted to validate the superiority of our MHN for person ReID over a wide variety of state-of-the-art methods on three large-scale datasets, including Market-1501, DukeMTMC-ReID and CUHK03-NP. Code is available at

Purpose This study was conducted to explore the clinical value of noninvasive assessment of bedside ultrasound in the diagnosis of lung lesions of Coronavirus Disease-19. Methods In this retrospective study, 30 patients with Coronavirus Disease-19 admitted to our hospital from January 18 to February 5, 2020, were selected as the research subjects. All cases were examined by lung ultrasound and CT. Lung lesions were reviewed by blinded observers, with imaging scores being used to analyze the ultrasound findings of lung lesions in patients with Coronavirus Disease-19 and with chest CT being used as the reference standard. The clinical value of ultrasound in the noninvasive assessment of lung lesions was evaluated. Results Lung ultrasound signs in patients with Coronavirus Disease-19 were mainly manifested as interstitial pulmonary edema (90.0 %, 27/30) and pulmonary consolidations (20.0 %, 6/30). The lung lesions were mainly distributed in the subpleural and peripheral pulmonary zones. The lower lobe and the dorsal region had a greater tendency to be involved. There was moderate agreement (Kappa = 0.529) between the noninvasive assessment of bedside ultrasound for lung lesions in patients with Coronavirus Disease-19 and CT. The ultrasound scores to evaluate mild, moderate and severe lung lesions exhibited sensitivity of 68.8 % (11/16), 77.8 % (7/9), 100.0 % (2/2), specificity of 85.7 % (12/14), 76.2 % (16/21), 92.9 % (26/28), and diagnostic accuracy of 76.7 % (23/30), 76.7 % (23/30), 93.3 % (28/30), respectively. The follow-up dynamic ultrasound examination showed that the condition of all patients worsened gradually, with the ultrasound scores of lung lesions increasing to varying degrees. Conclusion Though the diagnostic efficacy of bedside ultrasound is relatively low for mild to moderate patients, it is high for severe patients. Bedside ultrasound has important clinical significance for noninvasive assessment and dynamic observation of lung lesions in patients with Coronavirus Disease-19, which is worth further consideration.

Insightful understanding of how interfacial structures and properties affect catalytic processes is one of the most challenging issues in heterogeneous catalysis. Here, the essential roles of Pt-Au and Pt-oxide-Au interfaces on the activation of H and the hydrogenation of para-nitrothiophenol (pNTP) were studied at molecular level by in situ surface-enhanced Raman spectroscopy (SERS) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). Pt-Au and Pt-oxide-Au interfaces were fabricated through the synthesis of Pt-on-Au and Pt-on-SHINs nanocomposites. Direct spectroscopic evidence demonstrates that the atomic hydrogen species generated on the Pt nanocatalysts can spill over from Pt to Au via the Pt-Au and Pt-TiO-Au interfaces, but would be blocked at the Pt-SiO-Au interfaces, leading to the different reaction pathways and product selectivity on Pt-on-Au and Pt-on-SHINs nanocomposites. Such findings have also been verified by the density functional theory calculation. In addition, it is found that nanocatalysts assembled on pinhole-free shell-isolated nanoparticles (Pt-on-pinhole-free-SHINs) can override the influence of the Au core on the reaction and can be applied as promising platforms for the in situ study of heterogeneous catalysis. This work offers a concrete example of how SERS/SHINERS elucidate details about in situ reaction and helps to dig out the fundamental role of interfaces in catalysis.

Surface molecular information acquired in situ from a catalytic process can greatly promote the rational design of highly efficient catalysts by revealing structure-activity relationships and reaction mechanisms. Raman spectroscopy can provide this rich structural information, but normal Raman is not sensitive enough to detect trace active species adsorbed on the surface of catalysts. Here we develop a general method for in situ monitoring of heterogeneous catalytic processes through shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) satellite nanocomposites (Au-core silica-shell nanocatalyst-satellite structures), which are stable and have extremely high surface Raman sensitivity. By combining operando SHINERS with density functional theory calculations, we identify the working mechanisms for CO oxidation over PtFe and Pd nanocatalysts, which are typical low- and high-temperature catalysts, respectively. Active species, such as surface oxides, superoxide/peroxide species and Pd–C/Pt–C bonds are directly observed during the reactions. We demonstrate that in situ SHINERS can provide a deep understanding of the fundamental concepts of catalysis.

The ability to tune the surface partial charge of noble metal catalysts at the nanoscale size dimension is essential for harnessing the activity of nanocatalysts in many important environmental catalytic reactions, such as hydrocarbon oxidations. We report herein a synthetic pathway to control the catalyst−support interactions and enable a surface partial-charge-tuned enhancement of the nanocatalytic activity using titania-supported Pt nanoparticles for oxidation of toluene as a model system. This pathway involved the onepot wet-chemical synthesis of TiO 2 -supported ultrasmall Pt nanoparticles (1−5 nm) with a controlled morphology and size. The catalysts showed greatly enhanced activities for toluene oxidation, exhibiting a strong dependence on the support morphology (e.g., nanopowders, nanowires, nanotubes, and mesoporous structures). The tunable partial negative charges on Pt were achieved by suppressing roughening of the support surface, favoring O 2 spillover from TiO 2 to Pt. In situ DRIFT data further reveal two parallel pathways responsible for oxidation of the methyl group and opening of the aromatic ring, the latter of which is favored by the partial negatively charged Pt, leading to a high activity. These findings provided insights into tuning nanoscale catalytic properties, which has significant implications for the design of supported noble metal nanocatalysts for environmental catalysis.

Background Effective therapies are urgently needed for the SARS-CoV-2 pandemic. Chloroquine has been proved to have antiviral effect against coronavirus in vitro. In this study, we aimed to assess the efficacy and safety of chloroquine with different doses in COVID-19. Method In this multicenter prospective observational study, we enrolled patients older than 18 years old with confirmed SARS-CoV-2 infection excluding critical cases from 12 hospitals in Guangdong and Hubei Provinces. Eligible patients received chloroquine phosphate 500 mg, orally, once (half dose) or twice (full dose) daily. Patients treated with non-chloroquine therapy were included as historical controls. The primary endpoint is the time to undetectable viral RNA. Secondary outcomes include the proportion of patients with undetectable viral RNA by day 10 and 14, hospitalization time, duration of fever, and adverse events. Results A total of 197 patients completed chloroquine treatment, and 176 patients were included as historical controls. The median time to achieve an undetectable viral RNA was shorter in chloroquine than in non-chloroquine (absolute difference in medians -6.0 days; 95% CI -6.0 to -4.0). The duration of fever is shorter in chloroquine (geometric mean ratio 0.6; 95% CI 0.5 to 0.8). No serious adverse events were observed in the chloroquine group. Patients treated with half dose experienced lower rate of adverse events than with full dose. Conclusions Although randomised trials are needed for further evaluation, this study provides evidence for safety and efficacy of chloroquine in COVID-19 and suggests that chloroquine can be a cost-effective therapy for combating the COVID-19 pandemic.

Over the past few years, softmax and SGD have become a commonly used component and the default training strategy in CNN frameworks, respectively. However, when optimizing CNNs with SGD, the saturation behavior behind softmax always gives us an illusion of training well and then is omitted. In this paper, we first emphasize that the early saturation behavior of softmax will impede the exploration of SGD, which sometimes is a reason for model converging at a bad local-minima, then propose Noisy Softmax to mitigating this early saturation issue by injecting annealed noise in softmax during each iteration. This operation based on noise injection aims at postponing the early saturation and further bringing continuous gradients propagation so as to significantly encourage SGD solver to be more exploratory and help to find a better local-minima. This paper empirically verifies the superiority of the early softmax desaturation, and our method indeed improves the generalization ability of CNN model by regularization. We experimentally find that this early desaturation helps optimization in many tasks, yielding state-of-the-art or competitive results on several popular benchmark datasets.