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High-altitude pulmonary edema (HAPE) is a deadly form of altitude sickness, and there is no effective treatment for HAPE. Dental pulp stem cells (DPSCs) are a type of mesenchymal stem cell isolated from dental pulp tissues and possess various functions, such as anti-inflammatory and anti-oxidative stress. DPSCs have been used to treat a variety of diseases, but there are no studies on treating HAPE. In this study, Sprague-Dawley rats were exposed to acute low-pressure hypoxia to establish the HAPE model, and SOD1-modified DPSCs (DPSCsHiSOD1) were administered through the tail vein. Pulmonary arterial pressure, lung water content (LWC), total lung protein content of bronchoalveolar lavage fluid (BALF) and lung homogenates, oxidative stress, and inflammatory indicators were detected to evaluate the effects of DPSCsHiSOD1on HAPE. Rat type II alveolar epithelial cells (RLE-6TN) were used to investigate the effects and mechanism of DPSCsHiSOD1on hypoxia injury. We found that DPSCs could treat HAPE, and the effect was better than that of dexamethasone treatment. SOD1 modification could enhance the function of DPSCs in improving the structure of lung tissue, decreasing pulmonary arterial pressure and LWC, and reducing the total lung protein content of BALF and lung homogenates, through anti-oxidative stress and anti-inflammatory effects. Furthermore, we found that DPSCsHiSOD1could protect RLE-6TN from hypoxic injury by reducing the accumulation of reactive oxygen species (ROS) and activating the Nrf2/HO-1 pathway. Our findings confirm that SOD1 modification could enhance the anti-oxidative stress ability of DPSCs through the Nrf2/HO-1 signalling pathway. DPSCs, especially DPSCsHiSOD1, could be a potential treatment for HAPE.

Intelligent reflecting surface (IRS) usually consists of a large number of passive elements, for which the element-grouping strategies can be adopted to group adjacent elements into a sub-surface for lower computational complexity. For the grouped elements of a sub-surface, the linear gradient phase shift configuration can achieve directional IRS reflect beam towards the intended receiver. In this paper, we propose a practical scalable optimization framework for element-grouping IRS by adopting the amplitude-dependent phase-gradient directional beamforming, which induces a new amplitude-phase coupling to the reflected signal. Specifically, by deriving the phase-gradient condition from Fermat’s principle, we propose a practical phase-gradient IRS reflection model. Under this practical model, the amplitude-phase coupling becomes complicated, which brings technical challenges to the IRS beamforming optimization. We study a joint transmit and reflect beamforming optimization problem to minimize the transmit power. By designing a trigonometric transformation to deal with the complicated amplitude-phase coupling, we propose a penalty-based phase control strategy under given element grouping. Subsequently, to solve the element-grouping combinatorial problem with performance guarantee, we propose a low-complexity IRS reflect beamforming algorithm based on Markov approximation. Simulation results demonstrate that the proposed algorithm achieves substantial performance gains compared to conventional schemes.

To evaluate the accuracy of ultrasound (US) in determining the positions of parametrial implants by comparing US with magnetic resonance imaging (MRI) for advanced cervical cancer. Patients undergoing brachytherapy with parametrial implantation for cervical cancer from February 2017 to February 2019 were involved in the study. The transverse section of the cervix (surface S1) and the transverse section 1 cm above the external cervix (surface S2) were selected from MRI and US images as the observation planes. In the MRI observation plane, the distances between the uterine titanium needles and the uterine tube/implanter were set as M1to M4; in the US observation plane, the distances between the uterine titanium needles and the uterine tube/implanter were set as D1to D4. The differences and consistency in M and D of each group were then compared. There were no significant differences between M and D in each group (P= .058; P= .821; P= .870; and P= .936, respectively). The intraclass correlation coefficients of M and D in each group were 0.970, 0.968, 0.952, and 0.956. A regression analysis showed that the relationships between M and D in each group were as follows: M1= 0.9449D1+ 0.1812; M2= 0.9463D2+ 0.0965; M3= 0.9176D3+ 0.1233; and M4= 0.9253D4+ 0.1224. In parametrial brachytherapy for cervical cancer, US can accurately determine the positions of parametrial implantation needles, which is already applicable on MRI, and can provide assistance in parametrial brachytherapy for advanced cervical cancer.