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With the rapid development of media, the role of video quality assessment (VQA) is becoming increasingly significant. VQA has applications in many domains. For example, in the field of remote medical diagnosis, it can enhance the quality of video communication between doctors and patients. Besides, in sports broadcasting, it can improve video clarity. Within VQA, the human visual system (HVS) is a crucial component that should be taken into consideration. Considering that attention is guided by goal‐driven and top‐down factors, such as anticipated locations or some attractive frames within the video, we propose a blind VQA algorithm based on spatial‐temporal attention model. Specifically, we first use two pretrained convolutional networks to extract low‐level static‐dynamic fusion features. Then, a spatial attention‐guided model is established to get more representative features of frame‐level quality perception. Next, through a temporal attention‐guided model, the video‐level features are obtained. Finally, the features are fed into a regression model to calculate the final video quality score. The experiments conducted on seven VQA databases reach the state‐of‐the‐art performance, demonstrating the effectiveness of our proposed method. [ABSTRACT FROM AUTHOR]

Visual characteristics have the potential to assess the navigational proficiency of ship pilots. A precise assessment of ship piloting competence is imperative to mitigate human errors in piloting. An exhaustive examination of cognitive capabilities plays a pivotal role in developing an enhanced and refined system for classifying, selecting, and training ship piloting proficiency. Insufficiency in situation awareness (SA), denoting the cognitive underpinning of hazardous behaviors among pilots, may lead to subpar performance in ship pilotage when faced with adverse conditions. To address this issue, we propose an SA recognition model based on the random forest-support vector machine (RF-SVM) algorithm, which utilizes wearable eye-tracking technology to detect pilots' at-risk cognitive state, specifically low-SA levels. We rectify the relative error (RE) and root mean square error (RMSE) and employ principal component analysis (PCA) to enhance the RF algorithm, optimizing the combination of salient features in greater depth. Through the utilization of these feature combinations, we construct a SVM algorithm using the most suitable variables for SA recognition. Our proposed RF-SVM algorithm is compared to RF or SVM alone, and it achieves the highest accuracy in recognizing at-risk cognitive states under poor visibility conditions (an improvement of 86.79% to 93.43% in accuracy). Taken collectively, the present findings offer vital technical support for developing a technique-based intelligent system for adaptively evaluating the cognitive accomplishment of pilots. Furthermore, they establish the groundwork and framework for the surveillance of cognitive processes and capabilities in marine pilotage operations within China. [ABSTRACT FROM AUTHOR]

Biosensing approaches that combine small, engineered antibodies (nanobodies) with nanoparticles are often complicated. Here, we show that nanobodies with different C-terminal tags can be efficiently attached to a range of the most widely used biocompatible semiconductor quantum dots (QDs). Direct implementation into simplified assay formats was demonstrated by designing a rapid and wash-free mix-and-measure immunoassay for the epidermal growth factor receptor (EGFR). Terbium complex (Tb)-labeled hexahistidine-tagged nanobodies were specifically displaced from QD surfaces via EGFR-nanobody binding, leading to an EGFR concentration-dependent decrease of the Tb-to-QD Förster resonance energy transfer (FRET) signal. The detection limit of 80±20 pM (16±4 ng mL -1 ) was 3-fold lower than the clinical cut-off concentration for soluble EGFR and up to 10-fold lower compared to conventional sandwich FRET assays that required a pair of different nanobodies., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

A novel label-free fluorescence "turn-on" strategy was developed for the sensitive detection of Hg 2+ based on the thymine-Hg 2+ -thymine (T-Hg 2+ -T) coordination and the fact that single-stranded DNA (ssDNA) greatly enhances the fluorescence of terbium (III) (Tb 3+ ), but double-stranded DNA (dsDNA) does not. In the absence of Hg 2+ , the mercury-specific DNA (MSD) hybridized with the corresponding complementary strand (cDNA) to form a double helix structure in solution based on Watson-Crick base pairings, which cannot enhance the fluorescence of Tb 3+ . In the presence of Hg 2+ , MSD preferentially bound with Hg 2+ to form the T-Hg 2+ -T complex due to the strong affinity of Hg(II) for the T bases of DNA, thus avoiding the hybridization of the cDNA to MSD. The free cDNA can greatly enhance the emission of Tb 3+ , leading to a sharp increase in fluorescence intensity. Under the optimized conditions, the increased fluorescence intensity was proportional to the concentration of Hg 2+ in the range from 10 to 600 nM, and this method can detect concentrations of Hg 2+ as low as 0.24 nM. Moreover, satisfactory results were obtained for the detection of Hg 2+ in river water and fish samples, and the results were consistent with those from the atomic fluorescence spectroscopy (AFS). Thus, the fluorescence characteristics of Tb 3+ were here used in a "turn on" approach to detect Hg 2+ , which represents a new opportunity for Hg 2+ analysis in the field of environmental monitoring and food safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A novel aptamers-based fluorescence resonance energy transfer (FRET) assay was developed employing the oppositely charged thioglycolic acid-capped CdTe quantum dots (TGA-CdTe QDs) and cysteamine-stabilized gold nanoparticles (cysteamine-AuNPs). The fluorescence of TGA-CdTe QDs was significantly quenched with addition of cysteamine-AuNPs via the FRET. The FRET process can be modulated by 17β-estradiol in that the specific recognition between 17β-estradiol and aptamers could show different effects on the aptamers-mediated aggregation of cysteamine-AuNPs, and correspondingly adjust the FRET process. The feasibility of the method has been demonstrated by carrying out the detection of 17β-estradiol with the wide linear range from 0.5·ng mL-1 to 150 ng·mL-1 and the low detection limit of 0.057 ng·mL-1. The established assay exhibited favorable selectivity towards 17β-estradiol over other endocrine disrupting compounds and probably coexisting chemicals in real samples. Furthermore, the assay has been successfully applied to detect 17β-estradiol in real tap water samples and feeds samples with good performance. The results were in full consistence with those from HPLC method, indicating the reliability of the detection system. The aptamers-based FRET assay is expected to offer a new opportunity for the rapid analysis of 17β-estradiol in real samples.