Triboelectric nanogenerator (TENG) is an emerging powerful technology for converting ambient mechanical energy into electrical energy through the effect of triboelectricity. Starting from the ...expanded Maxwell’s equations, the theoretical framework of TENGs has been gradually established. Here, a review is given about its recent progress in constructing of this general theory. The fundamental mechanism of TENGs is constructed by the driving force—Maxwell’s displacement current, which is essentially different from that of electromagnetic generators. Theoretical calculations of the displacement current from a three-dimensional mathematical model are presented, as well as the theoretical studies on the TENGs according to the capacitor models. Furthermore, the figure-of-merits and standards for quantifying the TENG’s output characteristics are discussed, which will provide important guidelines for optimizing the structure and performance of TENGs toward practical applications. Finally, perspectives and challenges are proposed about the basic theory of TENGs and its future technology development.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
As the dominant component for precise motion measurement, angle sensors play a vital role in robotics, machine control, and personalized rehabilitation. Various forms of angle sensors have been ...developed and optimized over the past decades, but none of them would function without an electric power. Here, a highly sensitive triboelectric self‐powered angle sensor (SPAS) exhibiting the highest resolution (2.03 nano‐radian) after a comprehensive optimization is reported. In addition, the SPAS holds merits of light weight and thin thickness, which enables its extensive integrated applications with minimized energy consumption: a palletizing robotic arm equipped with the SPAS can precisely reproduce traditional Chinese calligraphy via angular data it collects. In addition, the SPAS can be assembled in a medicare brace to record the flexion/extension of joints, which may benefit personalized orthopedic recuperation. The SPAS paves a new approach for applications in the emerging fields of robotics, sensing, personalized medicare, and artificial intelligence.
Sensing angular information via the most energy‐efficient method is vitally important. After systematic optimization, a triboelectric self‐powered angle sensor provides high‐quality sensing signals while itself needing neither electric power supply nor a signal‐amplification module. In addition, its feasibility is proved by practical application in a robotic arm, precisely duplicating traditional Chinese calligraphy as well as medical brace monitoring joint motions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Electrowetting technique is an actuation method for manipulating position and velocity of fluids in the microchannels. By combining electrowetting technique and a freestanding mode triboelectric ...nanogenerator (TENG), we have designed a self-powered microfluidic transport system. In this system, a mini vehicle is fabricated by using four droplets to carry a pallet (6 mm × 8 mm), and it can transport some tiny object on the track electrodes under the drive of TENG. The motion of TENG can provide both driving power and control signal for the mini vehicle. The maximum load for this mini vehicle is 500 mg, and its highest controllable velocity can reach 1 m/s. Freestanding TENG has shown excellent capability to manipulate microfluid. Under the drive of TENG, the minimum volume of the droplet can reach 70–80 nL, while the tiny droplet can freely move on both horizontal and vertical planes. Finally, another strategy for delivering nanoparticles to the designated position has also been demonstrated. This proposed self-powered transport technique may have great applications in the field of microsolid/liquid manipulators, drug delivery systems, microrobotics, and human-machine interactions.
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IJS, KILJ, NUK, PNG, UL, UM
Contact electrification (CE) involves a complex interplay of physical interactions in realistic material systems. For this reason, scientific consensus on the qualitative and quantitative importance ...of different physical mechanisms on CE remains a formidable task. The CE mechanism at a water/polymer interface is a crucial challenge owing to the poor understanding of charge transfer at the atomic level. First-principle density functional theory (DFT), used in the present work, proposes a new paradigm to address CE. Our results indicate that CE follows the same trend as the gap between the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of polymers. Electron transfer occurs at the outmost atomic layer of the water/polymer interface and is closely linked to the functional groups and atom locations. When the polymer chains are parallel to the water layer, most electrons are transferred; conversely, if they are perpendicular to each other, the transfer of charges can be ignored. We demonstrate that a decrease in the interface distance between water and the polymer chains leads to CE in quantitative agreement with the electron cloud overlap model. We finally use DFT calculations to predict the properties of CE materials and their potential for triboelectric nanogenerator energy harvesting devices.
Hepatocellular carcinoma (HCC) is one of the most common cancers with high incidence and mortality. However, the underlying mechanisms of HCC still remain unclear. Eukaryotic translation initiation ...factors (eIFs) have a substantial effect on tumor development. In this study, we were aimed to investigate the role of eukaryotic translation initiation factor 4 gamma 2 (EIF4G2) in HCC.
Western blot (WB) of 30 paired HCC tissues and tissue microarrays (TMAs) conducted by immunohistochemistry (IHC) in 89 paired HCC samples were performed to assess EIF4G2 expression. Clone formation, real-time cell analysis (RTCA), wound healing and transwell assays were adopted to evaluate the role of EIF4G2 on HCC cell proliferation, migration and invasion abilities. The function of EIF4G2 in HCC tumor growth was assessed in a xenograft nude mouse model in vivo. The regulation of EIF4G2 by miR-144-3p was performed by luciferase reporter assay and WB.
The EIF4G2 protein was clearly upregulated in HCC tissues, and high EIF4G2 expression was closely related to HCC prognosis. EIF4G2 silencing could inhibit HCC cell growth and metastasis in vitro, and suppress tumorigenesis in vivo by repressing the ERK signaling pathway. The results of luciferase reporter assays, WB and IHC staining verified that EIF4G2 was negatively regulated by miR-144. And re-expression of EIF4G2 could partially reverse the inhibiting effect of miR-144 in HCC.
In summary, our study revealed the role of EIF4G2 in HCC development via the activation of the ERK pathway. We also found that EIF4G2 could be negatively regulated by the tumor suppressor miR-144. Our investigations indicated that EIF4G2 might be a promising therapeutic target in HCC.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Chondrocyte inflammation and catabolism are two major features in the progression of osteoarthritis (OA). Chelidonine, a principal alkaloid extracted from
Chelidonium majus
, is suggested to show ...anti-inflammation, anti-apoptosis, and anti-oxidation activities in various diseases. However, its potential effects on OA cartilage degeneration remains unclear. To evaluate the effect of chelidonine on OA and its underlying mechanism, we incubated chondrocytes with interleukin (IL)-1β and chelidonine at varying concentrations. Then, we performed the CCK-8 assay, fluorescence immunostaining, reverse transcription PCR, ELISA, and western blotting to evaluate cell viability, catabolic/inflammatory factors, levels of extracellular matrix (ECM)-related proteins, and the involved pathways. H&E and Safranin-O staining and ELISA were performed to measure cartilage degradation and synovial inflammation. Chelidonine suppressed the IL-1β-mediated catabolism and inflammation of chondrocytes. Chelidonine suppressed the NF-κB pathway activation. Similarly, our
in vivo
experiment showed that chelidonine partially attenuated cartilage degradation while inhibiting synovial inflammation. Chelidonine inhibited inflammation and catabolism through modulation of NF-κB pathways
in vitro
, thereby avoiding rat cartilage degeneration and synovial inflammation within OA.
Accurate short-term load forecasting of distribution transformer in extreme weather will effectively assist power dispatching and enable safe and stable operation of power grid. Therefore, this paper ...proposes the Bagging–XGBoost algorithm based extreme weather identification and short-term load forecasting model, which can warn the time period and detailed value of peak load in advance. Firstly, based on Extreme Gradient Boosting (XGBoost) algorithm, the idea of Bagging is introduced to reduce the output variance and enhance the generalization ability of the algorithm. Then, the mutual information (MI) between weather influencing factors and load is analyzed to adjust the input weight of the model and improve its ability to track weather changes. Next, considering the load, weather and time factors, the extreme weather identification model is established to determine the occurrence range of peak load. Finally, the specialized training set is selected based on the weighted similarity, and high-accuracy short-term load forecasting model is established. Compared with the traditional model, the model proposed in this paper reduces the average Mean Absolute Percentage Error (MAPE) of peak load by 3% to 10%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A method combined with MCRT, CFD and FEA is developed for studying for PTR’s structural reliability.•The effects of HTF velocity and temperature on the temperature difference of PTR were ...investigated.•The effects of HTF velocity and temperature on the thermal stress of PTR were investigated.•The metal tube deflection is weakly dependent on the thermal stress from non-uniform heat flux.•The metal tube deflection is highly dependent on its supporting conditions and neighboring PTR’s state.
Parabolic trough receivers typically account for 30% of the cost of a solar field. Furthermore, experiences show the cost of operation and maintenance of parabolic trough receivers over the lifetime of the system can be quite high as regular maintenance is required. Therefore, the receiver’s cost and structural reliability is crucial to guarantee the parabolic trough plants work steadily, safely and above all, economically. The structure of a parabolic trough receiver is principally a stainless steel inner tube surrounded by a glass outer tube. Because the stainless steel tube has 4m long and is easy to get bent, the glass outer tube is quite fragile and therefore prone to break. Experiences in field operations show the bending of stainless steel tube is the main reason of parabolic trough receiver’s structural failure. This study mainly investigates why and how the stainless steel tubes get bent. In this paper, an indoor experiment, numerical simulations (CFD and FEA) and field measurements are conducted to jointly investigate the causes of stainless steel tube’s bending. An indoor experiment is conducted on a heat loss test-rig, and the deflection of the stainless steel tube under different isothermal conditions is studied. Numerical simulations are used to investigate the detailed temperature distribution, and its corresponding structural deformation of the stainless steel tube of parabolic trough receivers. The simulations adapt a MCRT code, FLUENT software and ANSYS workbench. Finally, field measurements are conducted on a 36m long parabolic trough collector to investigate the stainless steel tube bending under different working conditions. This study shows that improper installation and operational practices of parabolic trough receivers are the main causes for the structural failure of the parabolic trough’s receiver. This study is of great importance to guide the installation and operation of parabolic trough receivers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Hepatocellular carcinoma (HCC) is a highly lethal type of malignancies that possesses great loss of life safety to human beings worldwide. However, few effective means of curing HCC exist and its ...specific molecular basis is still far from being fully elucidated. Activation of nuclear factor kappa B (NF-κB), which is often observed in HCC, is considered to play a significant part in hepatocarcinogenesis and development. The emergence of regulatory non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), is a defining advance in cancer biology, and related research in this branch has yielded many diagnostic and therapeutic opportunities. Recent studies have suggested that regulatory ncRNAs act as inhibitors or activators in the initiation and progression of HCC by targeting components of NF-κB signaling or regulating NF-κB activity. In this review, we attach importance to the role and function of regulatory ncRNAs in NF-κB signaling of HCC and NF-κB-associated chemoresistance in HCC, then propose future research directions and challenges of regulatory ncRNAs mediated-regulation of NF-κB pathway in HCC.
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