We propose a design strategy to fabricate a flexible bend sensor (BS) with ultrasensitivity toward airflow using all-poly(vinylidene fluoride) (PVDF) nanofiber web-based sensing elements and ...electrodes to monitor human respiration. The unique electrospinning (rotational speed of collector of 2000 rpm and tip-to-collector distance of 4 cm) with silver nanoparticle interfacing was introduced to prepare a Ag-doped oriented PVDF nanofiber web with high β-phase content as a sensing element (AgOriPVDF, β-phase crystallinity ∼44.5%). After that, a portion of the prepared AgOriPVDF was processed into a flexible and electrically conductive electrode through an electroless silver plating technique (SP-AgOriPVDF). Interestingly, the encapsulated AgOriPVDF BS with the SP-AgOriPVDF electrode exhibited superior piezoelectric bending response (open-circuit peak-to-peak output voltage, V p–p ≈ 4.6 V) to injected airflow, which is more than 200 times higher than that of the unpackaged randomly aligned PVDF nanofiber web BS with a conductive tape electrode (V p–p ≈ 0.02 V). In addition, the factors influencing the bend sensitivity of the BS such as the β-phase content, nanofiber orientation, flexibility of the electrode, and so forth were thoroughly analyzed and then discussed. We also demonstrated that the AgOriPVDF BS has sufficient capability to detect and identify various respiratory signals, presenting a great potential for wearable applications, for example, smart respiratory protective equipment.
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Wearable strain sensors have generated considerable recent research interest due to their huge potential in the real-time detection of human body deformation. State-of-the-art strain ...sensors are normally fabricated through conductive networks with a single sensing element, which always faces the challenge of either limited stretchability or inferior quality in sensitivity. In this work, we report a highly sensitive strain sensor based on a multi-functionalized fabric through carbonization and polymer-assisted copper deposition. The sensor shows high sensitivity (Gauge factor ∼ 3557.6 in the strain range from 0 to 48%), and outstanding stretchability up to the strain of 300%, which is capable of detecting different types of deformation of the human body. By integrating the high-performance sensor with a deep learning network, we demonstrate a high-accuracy respiration monitoring and emergency alarm system, showing the enormous application potential of the sensor in personal and public healthcare.
The ongoing coronavirus (COVID-19) pandemic requires enormous production of facemasks and related personal protection materials, thereby increasing the amount of nondegradable plastic waste. The core ...material for facemasks is melt-blown polypropylene (PP) fiber. Each disposable facemask consumes ∼0.7 g of PP fibers, resulting in annual global consumption and disposal of more than 1 150 000 tons of PP fibers annually. Herein, we developed a laser-assisted melt-blown (LAMB) technique to manufacture PP nanofibers with a quality factor of 0.17 Pa–1 and significantly reduced the filter’s weight. We demonstrated that a standard surgical facemask could be made with only 0.13 g of PP nanofibers, saving approximately 80% of the PP materials used in commercial facemasks. Theoretical analysis and modeling were also conducted to understand the LAMB process. Importantly, nanofibers can be easily scaled up for mass production by upgrading traditional melt blown line with scanning laser-assisted melt-blown (SLAMB).
This study analyzes the effects of R&D activities and government support programs for the product innovation of service industry. With the advent of the knowledge based society, the technology ...innovation of the service industry has become an important source of national competitiveness. However, the studies on technology innovation have focused on manufacturing industry not the service industry. This study analyzes how differently R&D activities and the government support programs have influence on product innovation by the size of companies and how the government support programs have a moderate effect in the relationship between the R&D activities and the innovation. The results of the study are as follows; first, in case of large enterprises, both the internal and external R&D activities were proven to be the important elements for product innovation. In case of SMEs, it was analyzed that only the internal R&D activities are significant. In other words, it was found that internal R&D activities are the important factors of product innovation for both big companies and SMEs. Second, only the direct financial support for SMEs had a positive effect on product innovation. This can be understood as a result relative to the effectiveness and necessity of direct financial support to SMEs' product innovation. Third, in the case of the moderating effect of the government support programs, the programs that provide indirect opportunity for innovation had the positive moderating effects only for SMEs. In conclusion, internal R&D activities were proved to be an important factor of product innovation for both large enterprises and SMEs. And government support programs have had a significant effect only in the case of SMEs. To have an impact on the moderated effect of the government support programs for SMEs, the internal R&D activities were confirmed. This study supports the direction of establishing SMEs support policies in the prospect of service sector innovation.
Nanog is a pivotal transcription factor in embryonic stem (ES) cells and is essential for maintaining the pluripotency and self-renewal of ES cells. SUMOylation has been proved to regulate several ...stem cell markers' function, such as Oct4 and Sox2. Nanog is strictly regulated by Oct4/Sox2 heterodimer. However, the direct effects of SUMOylation on Nanog expression remain unclear. In this study, we reported that SUMOylation repressed Nanog expression. Depletion of Sumo1 or its conjugating enzyme Ubc9 increased the expression of Nanog, while high SUMOylation reduced its expression. Interestingly, we found that SUMOylation of Oct4 and Sox2 regulated Nanog in an opposing manner. SUMOylation of Oct4 enhanced Nanog expression, while SUMOylated Sox2 inhibited its expression. Moreover, SUMOylation of Oct4 by Pias2 or Sox2 by Pias3 impaired the interaction between Oct4 and Sox2. Taken together, these results indicate that SUMOylation has a negative effect on Nanog expression and provides new insights into the mechanism of SUMO modification involved in ES cells regulation.
Partial Label Learning with a Partner Si, Chongjie; Jiang, Zekun; Wang, Xuehui ...
Proceedings of the ... AAAI Conference on Artificial Intelligence,
03/2024, Letnik:
38, Številka:
13
Journal Article, Conference Proceeding
Odprti dostop
In partial label learning (PLL), each instance is associated with a set of candidate labels among which only one is ground-truth. The majority of the existing works focuses on constructing robust ...classifiers to estimate the labeling confidence of candidate labels in order to identify the correct one. However, these methods usually struggle to rectify mislabeled samples. To help existing PLL methods identify and rectify mislabeled samples, in this paper, we introduce a novel partner classifier and propose a novel ``mutual supervision'' paradigm. Specifically, we instantiate the partner classifier predicated on the implicit fact that non-candidate labels of a sample should not be assigned to it, which is inherently accurate and has not been fully investigated in PLL. Furthermore, a novel collaborative term is formulated to link the base classifier and the partner one. During each stage of mutual supervision, both classifiers will blur each other's predictions through a blurring mechanism to prevent overconfidence in a specific label. Extensive experiments demonstrate that the performance and disambiguation ability of several well-established stand-alone and deep-learning based PLL approaches can be significantly improved by coupling with this learning paradigm.
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