Gut Microbiota Deficiency Exacerbates Liver Injury in Bile Duct Ligated Mice via Inflammation and Lipid Metabolism.

Bile components play a critical role in maintaining gut microbiota homeostasis. In cholestasis, bile secretion is impaired, leading to liver injury. However, it remains to be elucidated whether gut microbiota plays a role in cholestatic liver injury. Here, we performed a sham operation and bile duct ligation (BDL) in antibiotic-induced microbiome depleted (AIMD) mice and assessed liver injury and fecal microbiota composition in these mice. Significant reductions in gut microbiota richness and diversity were found in AIMD-sham mice when compared to sham controls. Three-day BDL leads to great elevation of plasma ALT, ALP, total bile acids, and bilirubin where reduced diversity of the gut microbiota was also found. AIMD further aggravated cholestatic liver injury evidenced by significantly higher levels of plasma ALT and ALP, associated with further reduced diversity and increased Gram-negative bacteria in gut microbiota. Further analyses revealed increased levels of LPS in the plasma of AIMD-BDL mice where elevated expression of inflammatory genes and decreased expression of hepatic detoxification enzymes were also found in liver when compared to the BDL group. These findings indicate that gut microbiota plays a critical role in cholestatic liver injury. Maintaining its homeostasis may alleviate liver injury in patients with cholestasis.

Multiagent Soft Actor-Critic Based Hybrid Motion Planner for Mobile Robots.

In this article, a novel hybrid multirobot motion planner that can be applied under no explicit communication and local observable conditions is presented. The planner is model-free and can realize the end-to-end mapping of multirobot state and observation information to final smooth and continuous trajectories. The planner is a front-end and back-end separated architecture. The design of the front-end collaborative waypoints searching module is based on the multiagent soft actor-critic (MASAC) algorithm under the centralized training with decentralized execution (CTDE) diagram. The design of the back-end trajectory optimization module is based on the minimal snap method with safety zone constraints. This module can output the final dynamic-feasible and executable trajectories. Finally, multigroup experimental results verify the effectiveness of the proposed motion planner.

A Local-and-Global Attention Reinforcement Learning Algorithm for Multiagent Cooperative Navigation.

The cooperative navigation algorithm is the crucial technology for multirobot systems to accomplish autonomous collaborative operations, and it is still a challenge for researchers. In this work, we propose a new multiagent reinforcement learning algorithm called multiagent local-and-global attention actor-critic (MLGA2C) for multiagent cooperative navigation. Inspired by the attention mechanism, we design the local-and-global attention module to dynamically extract and encode critical environmental features. Meanwhile, based on the centralized training and decentralized execution (CTDE) paradigm, we extend a new actor-critic method to handle feature encoding and make navigation decisions. We also evaluate the proposed algorithm in two cooperative navigation scenarios: static target navigation and dynamic pedestrian target tracking. The multiple experimental results show that our algorithm performs well in cooperative navigation tasks with increasing agents.

Gradient histogram estimation and preservation for texture enhanced image denoising.

Natural image statistics plays an important role in image denoising, and various natural image priors, including gradient-based, sparse representation-based, and nonlocal self-similarity-based ones, have been widely studied and exploited for noise removal. In spite of the great success of many denoising algorithms, they tend to smooth the fine scale image textures when removing noise, degrading the image visual quality. To address this problem, in this paper, we propose a texture enhanced image denoising method by enforcing the gradient histogram of the denoised image to be close to a reference gradient histogram of the original image. Given the reference gradient histogram, a novel gradient histogram preservation (GHP) algorithm is developed to enhance the texture structures while removing noise. Two region-based variants of GHP are proposed for the denoising of images consisting of regions with different textures. An algorithm is also developed to effectively estimate the reference gradient histogram from the noisy observation of the unknown image. Our experimental results demonstrate that the proposed GHP algorithm can well preserve the texture appearance in the denoised images, making them look more natural.

Disease progression in iridocorneal angle tissues of BMP2-induced ocular hypertensive mice with optical coherence tomography.

PURPOSE: The goal of the present study was to test for the first time whether glaucomatous-like disease progression in a mouse can be assessed morphologically and functionally with spectral domain optical coherence tomography (SD-OCT). METHODS: We monitored progressive changes in conventional outflow tissues of living mice overexpressing human bone morphogenetic protein 2 (BMP2), a model for glaucoma. Intraocular pressure (IOP) and outflow tissue morphology/Young's modulus were followed in mice for 36 days with rebound tonometry and SD-OCT, respectively. Results were compared to standard histological methods. Outflow facility was calculated from flow measurements with direct cannulation of anterior chambers subjected to three sequential pressure steps. RESULTS: Overexpression of BMP2 significantly elevated IOP in a biphasic manner over time compared to mice that overexpressed green fluorescent protein in outflow cells and naïve controls. SD-OCT revealed changes in outflow tissues overexpressing BMP2 that corresponded with the timing of the IOP phases and decreased outflow facility. In the first phase, the angle was open, but the trabecular meshwork and the cornea were thickened. OCT detected increased trabecular meshwork stiffness after provocative IOP challenges of the BMP2 eyes, which corresponded to increased collagen deposition with transmission electron microscopy. In contrast, the angle was closed in the second phase. IOP elevation over 36 days due to BMP2 overexpression resulted in significant retinal ganglion cell and axon loss. CONCLUSIONS: Although not a feasible open-angle glaucoma model, the BMP2 mice were useful for demonstrating the utility of SD-OCT in following disease progression and differentiating between two forms of ocular pathology over time that resulted in ocular hypertension.