Physics-Informed Neural Networks (PINNs) serve as a flexible alternative for tackling forward and inverse problems in differential equations, displaying impressive advancements in diverse areas of ...applied mathematics. Despite integrating both data and underlying physics to enrich the neural network's understanding, concerns regarding the effectiveness and practicality of PINNs persist. Over the past few years, extensive efforts in the current literature have been made to enhance this evolving method, by drawing inspiration from both machine learning algorithms and numerical methods. Despite notable progressions in PINNs algorithms, the important and fundamental field of data preprocessing remain unexplored, limiting the applications of PINNs especially in solving inverse problems. Therefore in this paper, a concise yet potent data preprocessing method focusing on data normalization was proposed. By applying a linear transformation to both the data and corresponding equations concurrently, the normalized PINNs approach was evaluated on the task of reconstructing flow fields in three turbulent cases. The results illustrate that by adhering to the data preprocessing procedure, PINNs can robustly achieve higher prediction accuracy for all flow quantities under different hyperparameter setups, without incurring extra computational cost, distinctly improving the utilization of limited training data. Though only verified in Navier-Stokes (NS) equations, this method holds potential for application to various other equations.
We conducted a numerical simulation of ventilated supercavitation from a forward-facing cavitator in unsteady flows generated by a gust generator under different gust angles of attack and gust ...frequencies. The numerical method is validated through the experimental results under specific steady and unsteady conditions. It has been shown that the simulation can capture the degree of cavity shape fluctuation and internal pressure variation in a gust cycle. Specifically, the cavity centerline shows periodic wavelike undulation with a maximum amplitude matching that of the incoming flow perturbation. The cavity internal pressure also fluctuates periodically, causing the corresponding change of difference between internal and external pressure across the closure that leads to the closure mode change in a gust cycle. In addition, the simulation captures the variation of cavity internal flow, particularly the development internal flow boundary layer along the cavitator mounting strut, upon the incoming flow perturbation, correlating with cavity deformation and closure mode variation. With increasing angle of attack, the cavity exhibits augmented wavelike undulation and pressure fluctuation. As the wavelength of the flow perturbation approaches the cavity length with increasing gust frequency, the cavity experiences stronger wavelike undulation and internal pressure fluctuation but reduced cavitation number variation.
Nitric oxide (NO) is a widely distributed gaseous signaling molecule in plants that can be synthesized through enzymatic and non-enzymatic pathways and plays an important role in plant growth and ...development, signal transduction, and response to biotic and abiotic stresses. Cadmium (Cd) is a heavy metal pollutant widely found in the environment, which not only inhibits plant growth but also enters humans through the food chain and endangers human health. To reduce or avoid the adverse effects of Cd stress, plants have evolved a range of coping mechanisms. Many studies have shown that NO is also involved in the plant response to Cd stress and plays an important role in regulating the resistance of plants to Cd stress. However, until now, the mechanisms by which Cd stress regulates the level of endogenous NO accumulation in plant cells remained unclear, and the role of exogenous NO in plant responses to Cd stress is controversial. This review describes the pathways of NO production in plants, the changes in endogenous NO levels in plants under Cd stress, and the effects of exogenous NO on regulating plant resistance to Cd stress.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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•Highly sensitive (GF = 21) sensor is developed using PDMS and PPy/Ag hybrid.•The PDMS substrate is simply biomimetic micropatterned by lotus leaf.•The multifunctional sensor can ...real-time monitor weak single of 0–60 mA.
Flexible electronic sensors, which can perceive and respond to mechanical stimuli, are essential components of wearable electronics. Here, the utilization of biomimetic microstructures from natural lotus leaves and freestanding polypyrrole/silver (PPy/Ag) hybrid films are demonstrated to design and fabricate multifunctional sensors. The sensors consist of sandwich structure, including the surface of the designed polydimethylsiloxane (PDMS) films with biomimetic micropattern and the interlayer of the conductive PPy/Ag film (PDMS/PPy/Ag/PDMS). It is discovered that the polypyrrole and silver nanoparticles (PPy/AgNPs) aggregated and the freestanding PPy/Ag hybrid film formed at the air/water interface under ultraviolet (UV) irradiation. The PPy/Ag film exhibits well electrical conductivity, which could be used for fabricating the sensors to detect pressures, stretching and bending forces. The sensors based on the micropatterned PDMS substrate show well strain gauge factor (≈21 for 18 ~ 20 strain) and pressure sensitivity (≈0.58 kPa−1 in 300 ~ 400 Pa) due to the effective contact areas. The sensors attract considerable attention for their application in monitoring finger pressure, respiration, acoustic vibrations, and real-time pulse wave at the current detection range from 0 to 60 mA. The results indicate that the PPy/Ag-based sensors with high sensitivity have promising potential for the future applications in wearable electronics and human-machine devices.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Chemokine (C–C motif) ligand 19 (CCL19) is a critical regulator of the induction of T cell activation, immune tolerance, and inflammatory responses during continuous immune surveillance, homeostasis, ...and development. Migration of CC-chemokine receptor 7 (CCR7)-expressing cells to secondary lymphoid organs is a crucial step in the onset of adaptive immunity, which is initiated by a complex interaction between CCR7 and its cognate ligands. Recent advances in knowledge regarding the response of the CCL19-CCR7 axis to viral infections have elucidated the complex network of interplay among the invading virus, target cells and host immune responses. Viruses use various strategies to evade or delay the cytokine response, gaining additional time to replicate in the host. In this review, we summarize the impacts of CCL19 and CCR7 expression on the regulation of viral pathogenesis with an emphasis on the corresponding signaling pathways and adjuvant mechanisms. We present and discuss the expression, signaling adaptor proteins and effects of CCL19 and CCR7 as these molecules differentially impact different viral infections and viral life cycles in host homeostatic strategies. The underlying mechanisms discussed in this review may assist in the design of novel agents to modulate chemokine activity for viral prevention.
Ship target detection is an important guarantee for the safe passage of ships on the river. However, the ship image in the river is difficult to recognize due to the factors such as clouds, buildings ...on the bank, and small volume. In order to improve the accuracy of ship target detection and the robustness of the system, we improve YOLOv3 network and present a new method, called Ship-YOLOv3. Firstly, we preprocess the inputting image through guided filtering and gray enhancement. Secondly, we use k-means++ clustering on the dimensions of bounding boxes to get good priors for our model. Then, we change the YOLOv3 network structure by reducing part of convolution operation and adding the jump join mechanism to decrease feature redundancy. Finally, we load the weight of PASCAL VOC dataset into the model and train it on the ship dataset. The experiment shows that the proposed method can accelerate the convergence speed of the network, compared with the existing YOLO algorithm. On the premise of ensuring real-time performance, the precision of ship identification is improved by 12.5%, and the recall rate is increased by 11.5%.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Exogenous abscisic acid (ABA) has been implicated in plant response to cadmium (Cd) stress, but the underlying mechanism remains unclear. In the present study, we found that exogenous ABA application ...decreased Cd fixation in wild type (WT) root cell wall through reducing the hemicelluloses content, in parallel with the decreased expression of IRT1, ZIP1, ZIP4, HMA2 and HMA4, which are related to Cd uptake and translocation, and the increased expression of PDF2.6, PDR8 and AIT1, which are related to Cd chelation, efflux, and accumulation inhibition. These changes might be associated with the reduced Cd accumulation in roots and shoots and the alleviated Cd toxicity. In contrast, the mutation of ABI4, a transcription factor in ABA signaling pathway, significantly increased the expression of IRT1, ZIP1, ZIP4, HMA2 and HMA4, while decreased the expression of AIT1, PDF2.6 and PDR8, enhancing Cd accumulation in roots and shoots of abi4. The enhanced Cd-sensitivity in abi4 mutant could not be rescued by exogenous ABA addition compared with WT. In a word, we conclude that exogenous ABA mitigates Cd toxicity in Arabidopsis thaliana via inhibiting Cd uptake, translocation and accumulation, promoting Cd chelation and efflux, a pathway that might be regulated by ABI4.
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•Exogenous ABA decreased the fixation of Cd in root cell wall hemicelluloses.•Exogenous ABA down-regulated the expression of genes related to Cd uptake and translocation.•Exogenous ABA alleviates Cd toxicity by promoting Cd efflux and cytoplasmic chelation rather than vacuolar chelation.•ABI4 might negatively regulate IRT1, ZIP1, ZIP4, HMA2 and HMA4, positively regulate PDF2.6 and PDR8.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Acyl carrier proteins (ACPs) are a group of small acidic proteins functioning as important cofactors in the
synthesis of fatty acids. In
, ACPs are encoded by a small gene family comprising five ...plastid members,
to
, and three mitochondrial members. The biological functions and the transcriptional responses to abiotic stresses of most AtACPs have yet to be elucidated. The present study extends previous findings and provides new knowledge on the function of ACPs by examining the responses of AtACP-encoding genes to several abiotic stresses and, in particular, the role of
in the adaptation to salt stress. Phylogenetic analysis showed that AtACP1, AtACP2, AtACP3, and AtACP5 can be classified into one group and separated from a group comprising AtACP4 and ACP homologs from related species. Quantitative RT-PCR analysis revealed that the expression of
, and
was induced by drought. Both iron deficiency and nitrogen starvation resulted in down-regulation of
. The most pronounced response was observed for
, the expression of which was dramatically decreased by salt stress. Knock-out of
showed increased sensitivity to NaCl stress, whereas transgenic lines overexpressing
displayed increased salt tolerance relative to the wild-type. Overexpression of
further led to an altered composition of fatty acids, mainly a decrease of oleic acid (C18:1) and an increase of palmitic acid (C16:0), and to a lower Na
/K
ratio when compared to the salt stressed wild-type. The comprehensive transcriptional information on the small plastid AtACP gene family in response to various abiotic stresses and the further investigation of the
indicate that
might be critical for salt tolerance through alterations of the composition of fatty acids and, subsequently, the Na
/K
ratio.
Phosphorus (P) starvation in rice facilitates the reutilization of root cell wall P by enhancing the pectin content. NaCl modulates pectin content, however, it is still unknown whether NaCl is also ...involved in the process of pectin regulated cell wall P remobilization in rice under P starved conditions. In this study, we found that 10 mmol/L NaCl increased the shoot and root biomasses under P deficiency to a remarkable extent, in company with the elevated shoot and root soluble P contents in rice. Further analysis indicated that exogenous NaCl enhanced the root cell wall P mobilization by increasing the pectin methylesterase activity and uronic acid content in pectin suggesting the involvement of NaCl in the process of cell wall P reutilization in P starved rice roots. Additionally, exogenous NaCl up-regulated the expression of P transporter OsPT6, which was induced by P deficiency, suggesting that NaCl also facilitated the P translocation prominently from root to shoot in P starved rice. Moreover, exogenous abscisic acid (ABA) can reverse the NaCl-mediated mitigation under P deficiency, indicating the involvement of ABA in the NaCl regulated root cell wall P reutilization. Taken together, our results demonstrated that NaCl can activate the reutilization of root cell wall P in P starved rice, which is dependent on the ABA accumulation pathway.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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