Significance of research on natural products from marine-derived Aspergillus species as a source against pathogenic bacteria

Bacterial infections pose a significant clinical burden on global health. The growing incidence of drug-resistant pathogens highlights the critical necessity to identify and isolate bioactive compounds from marine resources. Marine-derived fungi could provide novel lead compounds against pathogenic bacteria. Due to the particularity of the marine environment, Aspergillus species derived from marine sources have proven to be potent producers of bioactive secondary metabolites and have played a considerable role in advancing drug development. This study reviews the structural diversity and activities against pathogenic bacteria of secondary metabolites isolated from marine-derived Aspergillus species over the past 14 years (January 2010–June 2024), and 337 natural products (including 145 new compounds) were described. The structures were divided into five major categories—terpenoids, nitrogen-containing compounds, polyketides, steroids, and other classes. These antimicrobial metabolites will offer lead compounds to the development and innovation of antimicrobial agents

Understanding recent challenges and new food policy in China

Despite of remarkable achievements in the past, China is also facing several major challenges, in particular on ensuring sustainable growth of agriculture, improving food security, increasing farmers' income. The paper reviews China's agricultural and food policy with specific focus on recent challenges, initial policy responses and their consequences, and re-adjusting in policies. The results show that the policy responses to the challenges of sustainable agriculture are strong and encouraging. Adjusting the national food security target in response to sustainable agriculture and major efforts to improve food security are significant. To increase farmer's income, China has shifted its policy regime from taxing to subsidizing and protecting agriculture in the past decade. However, the results of these efforts are mixture. Price interventions increased farmers' income, they also resulted in several serious problems. Good news is that some new efforts to solve these problems may bring China's market reform back to the right track though they still needs to be evaluated. The paper concludes that the previous experiences on agricultural development through institutional reform, technology change, market reform, and investment in agriculture should still be the keys for successfully ensuring food security and sustainable agriculture for China in the future.National Natural Science Foundation of China [71333013]; Tsinghua University [CIRS2016-3]; Chinese Academy of Sciences [Y02015004, KSZD-EW-Z-021-1]SCI(E)SSCIARTICLE119-1261

Assessment of Hull and Propeller Performance Degradation Based on TSO-GA-LSTM

Evaluating the degradation of hull and ship performance and exploring their degradation pathways is crucial for developing scientific and reasonable ship maintenance plans. This paper proposes a two-stage optimization (TSO) algorithm that combines the Genetic Algorithm (GA) and Long Short-Term Memory (LSTM) network, capable of simultaneously optimizing input features and model parameters to enhance the accuracy and generalization ability of speed prediction models. Additionally, a performance degradation assessment method based on speed loss is provided, aimed at evaluating the degradation of hull and propeller performance, as well as extracting the performance degradation paths. The results indicated that the proposed TSO-LSTM-GA algorithm significantly outperformed existing baseline models. Furthermore, the provided performance degradation assessment method demonstrated certain effectiveness on the target ship data, with a measured degradation rate of 0.00344 kn/d and a performance degradation of 9.569% over 478 days, corresponding to an annual speed loss of 1.257 kn

Microstructure-sensitive modeling of competing failure mode between surface and internal nucleation in high cycle fatigue

Competing fatigue failure between the surface and internal nucleation has been widely observed in metals under the high cycle fatigue regime. To characterize different boundary conditions in surface and internal grain aggregates, a hybrid statistical volume element model was developed by binding two identical periodic stochastic polycrystal microstructure cubes together and superimposing them with a new 2.5 directional periodic boundary condition afterwards. Additional isotropic elastic media was attached on the surface of the hybrid statistical volume element model to represent the oxide layer formed at elevated temperature. Microstructure-sensitive modeling with a crystal plasticity model was implemented by computing multiple hybrid statistical volume elements under two stress levels. The results implied that grains in the surface volume of the hybrid statistical volume element generally tended to deform more easily than their counterparts in the internal one, and the oxide layer had a weak effect in suppressing the surface deformation. It was also demonstrated that the combination of the 2.5 directional periodic boundary condition, additional oxide layer and nonlinear constitutive model jointly brought stochastic effect into the two identical microstructural cubes. Significant competition between the surface and internal nucleation was captured under both stress levels. Since the detrimental influence of oxidation in accelerating crack formation was not considered, the lifetimes from both types of nucleation were overlaid on each other. Given the disruption of the oxide layer under high stress levels, the simulation reproduced the experimental discovery that the probability of surface nucleation increases with the ascending stress level. It is also clarified that the oxide layer cannot prevent surface nucleation under low stress levels, rejecting the hypothesis of the impact of the oxide layer on complete internal nucleation