Gradient-based autonomous obstacle avoidance trajectory planning for B-spline UAVs.

Unmanned aerial vehicles (UAVs) have become the focus of current research because of their practicability in various scenarios. However, current local path planning methods often result in trajectories with numerous sharp or inflection points, which are not ideal for smooth UAV flight. This paper introduces a UAV path planning approach based on distance gradients. The key improvements include generating collision-free paths using collision information from initial trajectories and obstacles. Then, collision-free paths are subsequently optimized using distance gradient information. Additionally, a trajectory time adjustment method is proposed to ensure the feasibility and safety of the trajectory while prioritizing smoothness. The Limited-memory BFGS algorithm is employed to efficiently solve optimal local paths, with the ability to quickly restart the trajectory optimization program. The effectiveness of the proposed method is validated in the Robot Operating System simulation environment, demonstrating its ability to meet trajectory planning requirements for UAVs in complex unknown environments with high dynamics. Moreover, it surpasses traditional UAV trajectory planning methods in terms of solution speed, trajectory length, and data volume.

Yersiniabactin-Producing E. coli Induces the Pyroptosis of Intestinal Epithelial Cells via the NLRP3 Pathway and Promotes Gut Inflammation.

The high-pathogenicity island (HPI) was initially identified in Yersinia and can be horizontally transferred to Escherichia coli to produce yersiniabactin (Ybt), which enhances the pathogenicity of E. coli by competing with the host for Fe3+. Pyroptosis is gasdermin-induced necrotic cell death. It involves the permeabilization of the cell membrane and is accompanied by an inflammatory response. It is still unclear whether Ybt HPI can cause intestinal epithelial cells to undergo pyroptosis and contribute to gut inflammation during E. coli infection. In this study, we infected intestinal epithelial cells of mice with E. coli ZB-1 and the Ybt-deficient strain ZB-1Δirp2. Our findings demonstrate that Ybt-producing E. coli is more toxic and exacerbates gut inflammation during systemic infection. Mechanistically, our results suggest the involvement of the NLRP3/caspase-1/GSDMD pathway in E. coli infection. Ybt promotes the assembly and activation of the NLRP3 inflammasome, leading to GSDMD cleavage into GSDMD-N and promoting the pyroptosis of intestinal epithelial cells, ultimately aggravating gut inflammation. Notably, NLRP3 knockdown alleviated these phenomena, and the binding of free Ybt to NLRP3 may be the trigger. Overall, our results show that Ybt HPI enhances the pathogenicity of E. coli and induces pyroptosis via the NLRP3 pathway, which is a new mechanism through which E. coli promotes gut inflammation. Furthermore, we screened drugs targeting NLRP3 from an existing drug library, providing a list of potential drug candidates for the treatment of gut injury caused by E. coli.

Hemolysin Co-Regulatory Protein 1 Enhances the Virulence of Clinically Isolated Escherichia coli in KM Mice by Increasing Inflammation and Inducing Pyroptosis.

Hemolysin-coregulated protein 1 (Hcp1) is an effector released by the type VI secretion system (T6SS) in certain pathogenic strains of Escherichia coli (E. coli) that causes apoptosis and contributes to the development of meningitis. The exact toxic consequences of Hcp1 and whether it intensifies the inflammatory response by triggering pyroptosis are yet unknown. Here, utilizing the CRISPR/Cas9 genome editing method, we removed the gene expressing Hcp1 from wild-type E. coli W24 and examined the impact of Hcp1 on E. coli virulence in Kunming (KM) mice. It was found that Hcp1-sufficient E. coli was more lethal, exacerbating acute liver injury (ALI) and acute kidney injury (AKI) or even systemic infections, structural organ damage, and inflammatory factor infiltration. These symptoms were alleviated in mice infected with W24Δhcp1. Additionally, we investigated the molecular mechanism by which Hcp1 worsens AKI and found that pyroptosis is involved, manifested as DNA breaks in many renal tubular epithelial cells. Genes or proteins closely related to pyroptosis are abundantly expressed in the kidney. Most importantly, Hcp1 promotes the activation of the NLRP3 inflammasome and the expression of active caspase-1, thereby cleaving GSDMD-N and accelerating the release of active IL-1ß and ultimately leading to pyroptosis. In conclusion, Hcp1 enhances the virulence of E. coli, aggravates ALI and AKI, and promotes the inflammatory response; moreover, Hcp1-induced pyroptosis is one of the molecular mechanisms of AKI.

Fabrication and Characterization of the Porous Ti4O7 Reactive Electrochemical Membrane.

Preparation of the Magnéli Ti4O7 reactive electrochemical membrane (REM) with high purity is of great significance for its application in electrochemical advanced oxidation processes (EAOPs) for wastewater treatment. In this study, the Ti4O7 REM with high purity was synthesized by mechanical pressing of TiO2 powders followed by thermal reduction to Ti4O7 using the Ti powder as the reducing reagent, where the TiO2 monolith and Ti powder were separated from each other with the distance of about 5 cm in the vacuum furnace. When the temperature was elevated to 1333 K, the Magnéli phase Ti4O7 REM with the Ti4O7 content of 98.5% was obtained after thermal reduction for 4 h. Noticeably, the surface and interior of the obtained REM bulk sample has a homogeneous Ti4O7 content. Doping carbon black (0wt%-15wt%) could increase the porosity of the Ti4O7 REM (38-59%). Accordingly, the internal resistance of the electrode and electrolyte and the charge-transfer impedance increased slightly with the increasing carbon black content. The optimum electroactive surface area (1.1 m2) was obtained at a carbon black content of 5wt%, which increased by 1.3-fold in comparison with that without carbon black. The as-prepared Ti4O7 REMs show high oxygen evolution potential, approximately 2.7 V/SHE, indicating their appreciable electrocatalytic activity toward the production of •OH.

An Eco-friendly Iron Cathode Electro-Fenton System Coupled With a pH-Regulation Electrolysis Cell for p-nitrophenol Degradation.

The high consumption of salt reagents and strict pH control are still bottlenecks for the full-scale application of the Fenton reaction. In this work, a novel eco-friendly iron cathode electrochemical Fenton (ICEF) system coupled with a pH-regulation divided electrolysis cell was developed. In a pH-regulation divided electrolysis system, the desired pH for an effective Fenton reaction and for a neutral treated media could be obtained by H2O splitting into H+ and OH- at the anode and cathode, respectively. In an ICEF system, an iron plate was used as the cathode to inhibit the release of iron ions and promote the reduction of Fe3+ to Fe2+. It was found that when a potential of 1.2 V/SCE was applied on the iron cathode, 98% of p-nitrophenol was removed in the combined system after 30 min with continuously adding 200 mg/L of H2O2. Meanwhile, a COD and TOC removal efficiency of 79 and 60% was obtained, respectively. In this case, the conductivity just slightly increased from 4.35 to 4.37 mS/cm, minimizing the increase of water salinity, as compared with the conventional Fenton process. Generally, this combined system was eco-friendly, energy-efficient, and has the potential of being a promising technology for the removal of bio-refractory organic pollutants from wastewaters.

Data-Driven Suboptimal Scheduling of Switched Systems.

In this paper, a data-driven optimal scheduling approach is investigated for continuous-time switched systems with unknown subsystems and infinite-horizon cost functions. Firstly, a policy iteration (PI) based algorithm is proposed to approximate the optimal switching policy online quickly for known switched systems. Secondly, a data-driven PI-based algorithm is proposed online solely from the system state data for switched systems with unknown subsystems. Approximation functions are brought in and their weight vectors can be achieved step by step through different data in the algorithm. Then the weight vectors are employed to approximate the switching policy and the cost function. The convergence and the performance are analyzed. Finally, the simulation results of two examples validate the effectiveness of the proposed approaches.

Investigation on luminescence of emission-tunable Ca5Y3Na2(PO4)5SiO4F2:Eu2+,Tb3+,Mn2+ phosphors for white LEDs.

To explore new single-phased white-light-emitting luminescent materials, a series of Eu2+-Tb3+-Mn2+ doped Ca5Y3Na2(PO4)5SiO4F2 (CYNPS) phosphors were synthesized by solid-state reaction method. Eu2+ in the CYNPS host shows a light blue emission band covering a broad range from 400 to 800 nm. When the Tb3+ or Mn2+ is codoped with Eu2+, obvious energy transfer from Eu2+ to Tb3+/Mn2+ appears, which increases the emission intensity of Tb3+/Mn2+ efficiently. To achieve white emission, the Eu2+-Tb3+-Mn2+ ions are tridoped. By adjusting the Mn2+ concentration, the emitting-light-color can be tuned conveniently. Warm white light was gained in the CYNPS:0.07Eu2+,0.18Tb3+,0.15Mn2+ phosphor with the chromaticity coordinates and correlated color temperature of (0.396, 0.369) and 3487 K, respectively. The investigation reveals that the present phosphors could have potential application in white LEDs.