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Peroxiredoxin 4 (Prdx4) in the endoplasmic reticulum (ER) is the only secretory member of the antioxidant Prdx family. Our previous studies demonstrated that Prdx4 in cumulus cells (CCs) ameliorated the maturation of oocytes in vitro and enhanced oocyte developmental competence by preventing CCs apoptosis caused by oxidative stress (OS) through gap junctions. In this study, we aimed to determine whether Prdx4 released by CCs can repair meiotic defects in mouse oocytes by co-culturing immature (germinal vesicle) oocytes with CCs from mature oocytes in the absence of gap junctions. The OS-induced meiotic defects in mouse oocytes were impeded by co-culture with CCs, as evidenced by the increased first polar body (PB1) extrusion rate and decreased ROS level. CCs increased Prdx4 expression and lowered IRE1α, Bip expression in H 2 O 2 -treated oocytes. After knockdown of Prdx4 expression in CCs, the rate of PB1 extrusion in the oocytes was significantly reduced to the level detected in H 2 O 2 group, and ER stress was not alleviated. CO-IP and immunofluorescence co-localization experiments demonstrated that Prdx4 interacted with PDIA6 in the oocytes and the Pearson's R value was 0.69 calculated using ImageJ. Cumulus cells can promote the maturation of oocytes in vitro by secreting Prdx4 in a paracrine manner and serve as a promising therapeutic antioxidant for improving the quality of oocytes, especially aging oocytes, in clinical in vitro maturation (IVM). • Cumulus cells could secrete Prdx4 in a paracrine manner. • Prdx4 interacts with PDIA6 to ameliorate the release of ROS, rectify misfolded protein. • Prdx4 supplementation might improve the oocyte quality. [ABSTRACT FROM AUTHOR]

Finding an effective regulator to avoid harmful effects caused by excessive reactive oxygen species (ROS) is a bottleneck during oocyte in vitro maturation (IVM). Previously, we found that peroxiredoxin 4 (Prdx4) expression is significantly higher in mature cumulus cell–oocyte complexes (COCs) than in immature COCs. Prdx4 belongs to the antioxidant enzyme family and can catalyze the reduction of H 2 O 2. In this study, we established an oxidative stress model with mouse COCs cultured in vitro. Treatment with H 2 O 2 decreased cumulus expansion indexes and oocyte maturation in a concentration-dependent manner, indicating follicular development dysplasia. Infection with a Prdx4-overexpressing adenovirus significantly attenuated H 2 O 2 -induced changes, exhibiting effects similar to those of the intracellular ROS scavenger tiron (the positive control). Furthermore, the results confirmed that the protective effect of Prdx4 on oocyte maturation may be due to reductions in ROS levels and apoptosis. However, when the gap junctions between cumulus cells (CCs) and oocytes were destroyed, Prdx4 overexpression did not exert antiapoptotic effects. The expression levels of the gap junction marker protein CX43 were significantly recovered in the Prdx4-overexpressing group. These results demonstrate that Prdx4 in CCs may be a new favorable regulator that improves in vitro -matured oocyte quality and enhances oocyte developmental competence by preventing CC apoptosis caused by oxidative stress through gap junctions. The findings expand the body of knowledge regarding follicle development, and the identification of Prdx4 as a new favorable regulator will aid in immature oocyte IVM. • The present study established an oxidative stress model of immature cumulus cells-oocytes cultured in vitro. • Prdx4 in cumulus cells may be a new favorable regulator that improves in vitro oocyte quality by preventing cell apoptosis caused by oxidative stress through gap junctions. • The investigation of Prdx4 as a new regulator will provide us a clue to improve the system of immature oocytes in vitro maturation. [ABSTRACT FROM AUTHOR]

Compressive Sensing for Magnetic Resonance Imaging (CS-MRI) aims to reconstruct Magnetic Resonance (MR) images from under-sampled raw data. There are two challenges to improve CS-MRI methods, i.e. designing an under-sampling algorithm to achieve optimal sampling, as well as designing fast and small deep neural networks to obtain reconstructed MR images with superior quality. To improve the reconstruction quality of MR images, we propose a novel deep convolutional neural network architecture for CS-MRI named MRCSNet. The MRCSNet consists of three sub-networks, a compressive sensing sampling sub-network, an initial reconstruction sub-network, and a refined reconstruction sub-network. Experimental results demonstrate that MRCSNet generates high-quality reconstructed MR images at various under-sampling ratios, and also meets the requirements of real-time CS-MRI applications. Compared to state-of-the-art CS-MRI approaches, MRCSNet offers a significant improvement in reconstruction accuracies, such as Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity (SSIM). Besides, it reduces the reconstruction error evaluated by the Normalized Root-Mean-Square Error (NRMSE). The source codes are available at https://github.com/TaihuLight/MRCSNet. [ABSTRACT FROM AUTHOR]

Deep reinforcement learning is one kind of machine learning algorithms which uses the maximum cumulative reward to learn the optimal strategy. The difficulty is how to ensure the fast convergence of the model and generate a large number of sample data to promote the model optimization. Using the deep reinforcement learning framework of the AlphaZero algorithm, the deployment problem of wireless nodes in wireless ad hoc networks is equivalent to the game of Go. A deployment model of mobile nodes in wireless ad hoc networks based on the AlphaZero algorithm is designed. Because the application scenario of wireless ad hoc network does not have the characteristics of chessboard symmetry and invariability, it cannot expand the data sample set by rotating and changing the chessboard orientation. The strategy of dynamic updating learning rate and the method of selecting the latest model to generate sample data are used to solve the problem of fast model convergence. [ABSTRACT FROM AUTHOR]