24 research outputs found

    Research on attitude control strategy of single engine failure in the first-stage flight phase of new generation launch vehicle

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    The successful launching of the new generation of launch vehicle is of great practical significance to the development of China Space, and the cryogenic liquid engine commonly used in the launch vehicle has a certain probability of failures, which may affect the success or failure of rocket launching. In this paper, a Bolza problem optimization algorithm based on Radau pseudo-spectral method is proposed to solve the problem of single engine failure in the first-stage flight phase of the new generation launch vehicle by simulating fault injection and taking the attitude angle as optimal control quantity. The simulation results show that this method can effectively eliminate the influence of single engine failure on orbit injection accuracy, achieve the fault absorption of new generation launch vehicle engine, improve the fault tolerance of attitude control system, and further guarantee the system reliability

    Image Inpainting Anti-Forensics Network via Attention-Guided Hierarchical Reconstruction

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    Privacy security and property rights protection have gradually attracted the attention of people. Users not only hope that the images edited by themselves will not be forensically investigated, but also hope that the images they share will not be tampered with. Aiming at the problem that inpainted images can be located by forensics, this paper proposes a general anti-forensics framework for image inpainting with copyright protection. Specifically, we employ a hierarchical attention model to symmetrically reconstruct the inpainting results based on existing deep inpainting methods. The hierarchical attention model consists of a structural attention stream and a texture attention stream in parallel, which can fuse hierarchical features to generate high-quality reconstruction results. In addition, the user’s identity information can be symmetrically embedded and extracted to protect copyright. The experimental results not only had high-quality structural texture information, but also had homologous features with the original region, which could mislead the detection of forensics analysis. At the same time, the protection of users’ privacy and property rights is also achieved

    Reversible Privacy Protection with the Capability of Antiforensics

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    In this paper, we propose a privacy protection scheme using image dual-inpainting and data hiding. In the proposed scheme, the privacy contents in the original image are concealed, which are reversible that the privacy content can be perfectly recovered. We use an interactive approach to select the areas to be protected, that is, the protection data. To address the disadvantage that single image inpainting is susceptible to forensic localization, we propose a dual-inpainting algorithm to implement the object removal task. The protection data is embedded into the image with object removed using a popular data hiding method. We further use the pattern noise forensic detection and the objective metrics to assess the proposed method. The results on different scenarios show that the proposed scheme can achieve better visual quality and antiforensic capability than the state-of-the-art works

    Anti-forensics of diffusion-based image inpainting

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    Protection of retina by αB crystallin in sodium iodate induced retinal degeneration.

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    Age-related macular degeneration (AMD) is a leading cause of blindness in the developed world. The retinal pigment epithelium (RPE) is a critical site of pathology in AMD and αB crystallin expression is increased in RPE and associated drusen in AMD. The purpose of this study was to investigate the role of αB crystallin in sodium iodate (NaIO3)-induced retinal degeneration, a model of AMD in which the primary site of pathology is the RPE. Dose dependent effects of intravenous NaIO3 (20-70 mg/kg) on development of retinal degeneration (fundus photography) and RPE and retinal neuronal loss (histology) were determined in wild type and αB crystallin knockout mice. Absence of αB crystallin augmented retinal degeneration in low dose (20 mg/kg) NaIO3-treated mice and increased retinal cell apoptosis which was mainly localized to the RPE layer. Generation of reactive oxygen species (ROS) was observed with NaIO3 in mouse and human RPE which increased further after αB crystallin knockout or siRNA knockdown, respectively. NaIO3 upregulated AKT phosphorylation and peroxisome proliferator-activator receptor-γ (PPARγ) which was suppressed after αB crystallin siRNA knockdown. Further, PPARγ ligand inhibited NaIO3-induced ROS generation. Our data suggest that αB crystallin plays a critical role in protection of NaIO3-induced oxidative stress and retinal degeneration in part through upregulation of AKT phosphorylation and PPARγ expression

    Certain Dietary Nutrients Reduce the Risk of Eye Affliction/Retinopathy in Individuals with Diabetes: National Health and Nutrition Examination Survey, 2003–2018

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    As the global trend of diabetes intensifies, the burden of vision-threatening retinopathy, particularly diabetic retinopathy (DR), is increasing. There is an urgent need to seek strategies for early prevention and control of DR. This study attempted to comprehensively evaluate the relationship between dietary nutrient intake and the risk of DR to provide assistance for doctors in guiding the diet of diabetic patients. Data from eligible participants with diabetes from the US National Health and Nutrition Examination Survey (NHANES) from 2003–2018 were analyzed. Univariate logistic regression was used to assess the association between 58 dietary nutrient intakes and self-reported eye disease risk. Multivariate logistic regression model was used to further evaluate the relationship between the two groups after adjusting relevant confounding factors. A total of 4595 diabetic patients were included. People with self-reported eye affliction/retinopathy had lower dietary fiber, butanoic, octanoic, vitamin A, alpha-carotene, folate, magnesium, copper and caffeine intake compared to those without self-reported eye affliction/retinopathy. The pooled ORs (95% CIs) were 0.78 (0.62–0.98), 0.79 (0.63–0.99), 0.72 (0.58–0.91), 0.74 (0.59–0.93), 0.70 (0.55–0.88), 075 (0.60–0.95), 0.79 (0.64–0.99), 0.67 (0.54–0.84) and 0.80 (0.64–0.99). Dietary cholesterol and hexadecenoic intake were higher, with the pooled ORs (95% CIs) of 1.26 (1.01–1.58) and 1.27 (1.02–1.59), respectively. Our research found that among dietary nutrients, dietary fiber, butanoic, octanoic, vitamin A, alpha-carotene, folate, magnesium, copper and caffeine intake reduced the occurrence of DR. Cholesterol and hexadecenoic intake promoted the occurrence of DR. This suggests that certain dietary nutrients should be paid more attention in the prevention of DR

    Distinguished Functions of Microglia in the Two Stages of Oxygen-Induced Retinopathy: A Novel Target in the Treatment of Ischemic Retinopathy

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    Microglia is the resident immune cell in the retina, playing the role of immune surveillance in a traditional concept. With the heated focus on the mechanisms of microglia in pathological conditions, more and more functions of microglia have been discovered. Although the regulating role of microglia has been explored in ischemic retinopathy, little is known about its mechanisms in the different stages of the pathological process. Here, we removed microglia in the oxygen-induced retinopathy model by PLX5622 and revealed that the removal of activated microglia reduced pathological angiogenesis in the early stage after ischemic insult and alleviated the over-apoptosis of photoreceptors in the vessel remodeling phase. Our results indicated that microglia might play distinguished functions in the angiogenic and remodeling stages, and that the inhibition of microglia might be a promising target in the future treatment of ischemic retinopathy

    Endothelial Notch Signaling Regulates the Function of the Retinal Pigment Epithelial Barrier via EC Angiocrine Signaling

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    The outer blood–retina barrier (oBRB), comprises tightly connected retinal pigment epithelium (RPE) cells, Bruch’s membrane, and choroid blood vessels, and is essential for retinal health and normal visual function. Disruption of the RPE barrier and its dysfunction can lead to retinal disorders such as age-related macular degeneration (AMD). In the present study, we investigated the essential role of choroid endothelial cells (ECs) in the RPE barrier formation process and its dysfunction. We discovered that ECs promoted RPE barrier formation through angiocrine signaling. Through blocking or activating endothelial Notch signaling and conducting experiments in vitro and in vivo, we confirmed that endothelial Notch signaling regulated the expression of heparin-binding epidermal growth factor (HBEGF) and consequently impacted the expression and activity of matrix metalloproteinases (MMP)-9 in RPE cells. This modulation influenced the RPE extracellular matrix deposition, tight junctions and RPE barrier function. In in vivo experiments, the intravitreal administration of recombinant HBEGF (r-HBEGF) alleviated the RPE barrier disruption induced by subretinal injection (SI) or laser treatment and also rescued RPE barrier disruption in endothelial Notch-deficient mice. Our results showed that the endothelial Notch signaling drove HBEGF expression through angiocrine signaling and effectively improved RPE barrier function by regulating the MMP-9 expression in RPE cells. It suggests that the modulation of Notch signaling in the choroidal endothelium may offer a novel therapeutic strategy for retinal degenerative diseases

    High-Power Acoustic-Optical Q-Switched 1.83 µm Tm-Doped Bulk Laser

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    We report on a high-power acoustic-optical (AO) Q-switched Tm:YLF laser operating at ~1.83 μm by controlling the transmittance of the output coupler. Under the continuous-wave (CW) operation, the maximum output power of 13 W is achieved, and the slope efficiency is up to 32.7%. With a YAG etalon inserted into the cavity, the linewidth is compressed below 0.5 nm with a maximum output power of 12.2 W. In the Q-switched state, the maximum pulsed output power of 10.32 W is achieved with a pulse duration of 150 ns when the repetition rate is 15 kHz. And the maximum pulsed energy of 1.13 mJ is generated with a duration of 131 ns at 5 kHz. As far as we know, this is the highest output power reported for the CW and pulsed 1.83 μm laser. In addition, the relationship between the output wavelength and crystal length is theoretically analyzed, which shows that increasing the loss of 1880 nm is the key to high-power 1.83 μm laser output

    Reduced ERG amplitudes in NaIO<sub>3</sub>-treated αB crystallin knockout (αB-/-) mice.

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    <p>Three weeks after tail vein injection of 20/kg body weight NaIO<sub>3</sub>, mesopic ERG responses were recorded in PBS-treated WT, NaIO<sub>3</sub>-treated WT, PBS-treated αB-/-, and NaIO<sub>3</sub>-treated αB-/- mice (representative ERGs shown in A). The amplitudes of <i>a</i> wave of the ERG of NaIO<sub>3</sub>-treated αB-/- mice decreased by 68.3% compared with that of PBS-treated αB-/- mice (B). The amplitudes of <i>b</i> wave of the ERG of NaIO<sub>3</sub>-treated αB-/- mice decreased by 55.3%, compared with that of PBS-treated αB-/- mice (C). Data are mean ± SEM, n = 5/group, *P<0.05, **P<0.01.</p
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