Explore the vast range of titles available.

This paper takes into consideration the excellent energy absorption ability of hierarchical honeycombs and auxetic structures and proposes a novel auxetic hierarchical crash box assembled by the auxetic hierarchical filling cores and the outer square thin-walled tube. The crushing performance of the auxetic hierarchical crash box is systematically investigated. The comparisons of energy absorption ability are made among the auxetic hierarchical crash box, aluminum foam-filled crash box, and the traditional crash box. In addition, a multi-objective optimization design is conducted based on the surrogate model with higher accuracy. The non-dominated sorting genetic algorithm (NSGA-II) and archive-based micro genetic algorithm (AMGA) are, respectively, employed to obtain the pareto sets. The results show that the optimum solution with AMGA has a smaller relative error, and the multi-objective optimization successfully improves the crushing performance of the auxetic hierarchical crash box. The electric vehicle crashworthiness is remarkably improved by the application of the auxetic hierarchical crash box. The conclusions of this paper can provide a new solution for the design of the crash box.

The applications of fucoidan in the food industry were limited due to its high molecular weight and low solubility. Moderate degradation was required to depolymerize fucoidan. A few studies have reported that fucoidan has potential antibacterial activity, but its antibacterial mechanism needs further investigation. In this study, the degraded fucoidans were obtained after ultraviolet/hydrogen peroxide treatment (UV/H2O2) at different times. Their physicochemical properties and antibacterial activities against Staphylococcus aureus and Escherichia coli were investigated. The results showed that the average molecular weights of degraded fucoidans were significantly decreased (up to 22.04 times). They were mainly composed of fucose, galactose, and some glucuronic acid. Fucoidan degraded for 90 min (DFuc-90) showed the strongest antibacterial activities against Staphylococcus aureus and Escherichia coli, with inhibition zones of 27.70 + 0.84 mm and 9.25 + 0.61 mm, respectively. The minimum inhibitory concentrations (MIC) were 8 mg/mL and 4 mg/mL, respectively. DFuc-90 could inhibit the bacteria by damaging the cell wall, accumulating intracellular reactive oxygen species, reducing adenosine triphosphate synthesis, and inhibiting bacterial metabolic activity. Therefore, UV/H2O2 treatment could effectively degrade fucoidan and enhance its antibacterial activity.

Reinforcement learning provides a general framework for achieving autonomy and diversity in traditional robot motion control. Robots must walk dynamically to adapt to different ground environments in complex environments. To achieve walking ability similar to that of humans, robots must be able to perceive, understand and interact with the surrounding environment. In 3D environments, walking like humans on rugged terrain is a challenging task because it requires complex world model generation, motion planning and control algorithms and their integration. So, the learning of high-dimensional complex motions is still a hot topic in research. This paper proposes a deep reinforcement learning-based footstep tracking method, which tracks the robot’s footstep position by adding periodic and symmetrical information of bipedal walking to the reward function. The robot can achieve robot obstacle avoidance and omnidirectional walking, turning, standing and climbing stairs in complex environments. Experimental results show that reinforcement learning can be combined with real-time robot footstep planning, avoiding the learning of path-planning information in the model training process, so as to avoid the model learning unnecessary knowledge and thereby accelerate the training process.

Both theory and observations suggest that outflows driven by an active central supermassive black hole have a feedback effect on shaping the global properties of the host galaxy 1 – 8 . However, whether feedback from the outflow is effective, and if so, whether it is positive or negative, have long been controversial. Here, using the latest catalogue from the Sloan Digital Sky Survey, we use the flux ratio of the [O  ii ] to [Ne  v ] emission lines as a proxy to compare the star formation rate in the hosts of quasars with different types of broad absorption lines (BALs): low-ionization (Lo)BAL, high-ionization (Hi)BAL and non-BAL. We find that the star formation rate decreases from LoBAL to HiBAL quasars, and then increases from HiBAL to non-BAL quasars. Assuming that the sequence of LoBAL to HiBAL to non-BAL represents evolution, our results are consistent with a quenching and subsequent rebound of star formation in quasar host galaxies. This phenomenon can be explained by suppression of the star formation rate by the outflow and then rebound of the rate once the outflow disappears as the quasars evolve from HiBALs to non-BALs. Our result suggests that the quasar outflow has a negative global feedback on galaxy evolution. Through an analysis of broad absorption lines in a range of quasars, quasar outflows are shown to have a negative global feedback effect on star formation, demonstrated by the recovery of star formation rates after the outflows disappear.

The lung is the primary organ targeted by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), making respiratory failure a leading coronavirus disease 2019 (COVID-19)-related mortality. However, our cellular and molecular understanding of how SARS-CoV-2 infection drives lung pathology is limited. Here we constructed multi-omics and single-nucleus transcriptomic atlases of the lungs of patients with COVID-19, which integrate histological, transcriptomic and proteomic analyses. Our work reveals the molecular basis of pathological hallmarks associated with SARS-CoV-2 infection in different lung and infiltrating immune cell populations. We report molecular fingerprints of hyperinflammation, alveolar epithelial cell exhaustion, vascular changes and fibrosis, and identify parenchymal lung senescence as a molecular state of COVID-19 pathology. Moreover, our data suggest that FOXO3A suppression is a potential mechanism underlying the fibroblast-to-myofibroblast transition associated with COVID-19 pulmonary fibrosis. Our work depicts a comprehensive cellular and molecular atlas of the lungs of patients with COVID-19 and provides insights into SARS-CoV-2-related pulmonary injury, facilitating the identification of biomarkers and development of symptomatic treatments. Wang et al. analysed post-mortem samples of the lungs of patients with COVID-19 by bulk and single-nucleus RNA sequencing along with proteomics and discovered lung senescence as a feature of COVID-19 pathology.

Uneven terrain walking is hard to achieve for most child-size humanoid robots, as they are unable to accurately detect ground conditions. In order to reduce the demand for ground detection accuracy, a walking control framework based on centroidal momentum allocation is studied in this paper, enabling a child-size humanoid robot to walk on uneven terrain without using ground flatness information. The control framework consists of three controllers: momentum decreasing controller, posture controller, admittance controller. First, the momentum decreasing controller is used to quickly stabilize the robot after disturbance. Then, the posture controller restores the robot posture to adapt to the unknown terrain. Finally, the admittance controller aims to decrease contact impact and adapt the robot to the terrain. Note that the robot uses a mems-based inertial measurement unit (IMU) and joint position encoders to calculate centroidal momentum and use force-sensitive resistors (FSR) on the robot foot to perform admittance control. None of these is a high-cost component. Experiments are conducted to test the proposed framework, including standing posture balancing, structured non-flat ground walking, and soft uneven terrain walking, with a speed of 2.8 s per step, showing the effectiveness of the momentum allocation method.

The eROSITA bubbles are detected via the instrument with the same name. The northern bubble shows noticeable asymmetric features, including distortion to the west and enhancement in the eastern edge, while the southern counterpart is significantly dimmer. Their origins are debated. Here, we performed hydrodynamic simulations showing that asymmetric eROSITA bubbles favor a dynamic, circumgalactic medium wind model, but disfavor other mechanisms such as a non-axisymmetric halo gas or a tilted nuclear outflow. The wind from the east by north direction in Galactic coordinates blows across the northern halo with a velocity of about 200 km s −1 , and part of it enters the southern halo. This creates a dynamic halo medium and redistributes both density and metallicity within. This naturally explains the asymmetric bubbles in both the morphology and surface brightness. Our results suggest that our Galaxy is accreting low-abundance circumgalactic medium from one side while providing outflow feedback. The origins of the pair of X-ray bubbles, called eROSITA bubbles (eRBs), detected in the halo of Milky Way are debated. Here, the authors show hydrodynamical simulations suggesting circumgalactic medium wind model can explain asymmetric eRBs.

Lignin-derived aromatic compounds have significant potential for multiple industrial applications, and elucidating the processes for bacterial lignin degradation processes can facilitate the utilization of plant biomass. A lignin-degrading bacterial strain, designated HZC-1, was newly isolated from saline-alkali soil and exhibited robust growth in 1–18% (w/v) NaCl and across a pH range of 5.0–11.0. The isolate showed the highest 16S rRNA gene sequence similarity (≤ 97.7%) to known Salinicoccus species. Furthermore, average nucleotide identity (≤ 82.34) and digital DNA-DNA hybridization (≤ 52.9%) analyses supported its classification as a potentially novel species within the genus Salinicoccus . Genomic annotation indicated that strain HZC-1 adapted to saline-alkali environments via multiple mechanisms such as Na + /H + antiporter and glycine betaine transport systems. By combining genomic and untargeted metabolomic data, it can be inferred that this strain was capable of metabolizing lignin derivatives through non-classical pathways involving enzymes such as β-glucosidase, aromatic cyclohydroxyl dioxygenase and those associated with naphthalene degradation. These findings suggest the potential lignin-degrading capacity of Salinicoccus sp. HZC-1 under saline-alkali conditions, presenting a potentially novel bacterial taxon for waste lignin valorization and bioremediation of aromatic pollutants.

Through the dynamic mechanical analysis of lithium perchlorate/polyvinyl alcohol–based aluminized electrically controlled solid propellants, the temperature spectrum of the storage modulus ( E ′ ), loss modulus ( E ″ ), and loss factor (tan δ ) of the propellant was obtained. Furthermore, the effects of Al content, particle size, grade, vibration frequency, and temperature on the dynamic mechanical properties of electrically controlled solid propellant (ECSP) were analyzed. In addition, the activation energy of the glass transition of aluminized ECSPs was calculated using the Arrhenius equation. Results showed that E ′ , E ″ , and tan δ of the propellant are closely related to solid filler, vibration frequency, and temperature. Moreover, the addition of Al increases E ′ of ECSP, but the response characteristics of aluminized ECSP to frequency are lower than those of the ECSP matrix. Results also showed that as the Al content in the propellant increases, E ′ and E ″ of the propellant show an increasing trend. Furthermore, the propellant has higher E ′ and E ″ in the glassy state at low temperature and lower E ′ and E ″ in the viscoelastic state at high temperature. The dynamic mechanical change process of ECSP and its matrix only has one glass transition peak. The glass transition temperature is frequency dependent and moves toward high temperature as the frequency increases. The propellant with Al (5 μ m) to Al (65 μ m) ratio of 3/7 has the largest storage modulus, and the surface activation energy required for glass transition is 270.19 kJ mol −1 .

The incidence and mortality of colorectal cancer have shown an upward trend in the past decade. Therefore, the prevention, diagnosis, and treatment of colorectal cancer still need our continuous attention. Finding compounds with strong anticancer activity and low toxicity is a good strategy for colorectal cancer (CRC) therapy. Trametes versicolor is a traditional Chinese medicinal mushroom with a long history of being used to regulate immunity and prevent cancer. Its extractions were demonstrated with strong cell growth inhibitory activity on human colorectal tumor cells, while the anticancer activity of them is not acted through a direct cytotoxic effect. However, the intricacy and high molecular weight make mechanistic research difficult, which restricts their further application as a medication in clinical cancer treatment. Recent research has discovered a small molecule polysaccharide peptide derived from Trametes versicolor that has a distinct structure after decades of Trametes versicolor investigation. Uncertain molecular weight and a complex composition are problems that have been solved through studies on its structure, and it was demonstrated to have strong anti-proliferation activity on colorectal cancer in vitro and in vivo via interaction with EGFR signaling pathway. It opens up new horizons for research in this field, and these low molecular weight polysaccharide peptides provide a new insight of regulation of colorectal cancer proliferation and have great potential as drugs in the treatment of colorectal cancer.