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Introduction: Mental health problems, especially depressive symptoms, are becoming increasingly prominent, posing a significant risk to public health. Changes in the body mass index (BMI) may impact an individual's mental health, however, the relationship between BMI and depressive symptoms is unclear. The purpose of this study was to investigate the association between BMI and depressive symptoms. Methods: Using a multi-stage sampling method, 10,686 adults in Longgang District, Shenzhen City, Guangdong Province, China, were selected for participation in this study. Surveys were distributed in 2020 and 2021 to measure participant demographic data and health. Binary logistic regression, restricted cubic spline regression, and subgroup analyses were performed to explore the relationship between BMI and depressive symptoms. Results: The results showed a U-shaped relationship between BMI and depression. Both obesity and underweight increased the risk of depression among the participants, especially in subgroups of participants who were young, highly educated, single and employed. Conclusion: These findings suggest that adults should try to maintain a normal body weight as a way to prevent depression and maintain their physical and mental health. [ABSTRACT FROM AUTHOR]

The chicken infectious anemia virus (CIAV) has been reported in major poultry-producing countries and poses a significant threat to the poultry industry worldwide. In this study, two Marek's disease virus (MDV) recombinants, rMDV-CIAV-1 and rMDV-CIAV-2, were generated by inserting the CIAV VP1 and VP2 genes into the MDV vaccine strain 814 at the US2 site using the fosmid-based rescue system. For rMDV-CIAV-1, an internal ribosome entry site was inserted between VP1 and VP2, so that both proteins were produced from a single open reading frame. In rMDV-CIAV-2, VP1 and VP2 were cloned into different open reading frames and inserted into the MDV genome. The recombinant viruses simultaneously expressed VP1 and VP2 in infected chicken embryo fibroblasts and exhibited growth kinetics similar to those of the parent MDV. The two recombinant viruses induced antibodies against CIAV in chickens. A single dose of the recombinant viruses provided strong protection against CIAV-induced anemia in chickens. These recombinant VP1- and VP2-expressing MDVs are potential vaccines against CIAV in chickens. [ABSTRACT FROM AUTHOR]

The design of lifting blade shapes is a key engineering application, especially in domains such as those of marine propellers, hydrofoils, and tidal energy converters. In particular, the excitation frequency must be different from that of the structure to avoid resonance. The natural frequency in the cases where the fluid–structure interaction (FSI) is considerably different if considering the coupling added mass (AM) of the water. In this study, vibration experiments were performed using a real propeller in air and water. The modal parameters, natural frequencies, and mode shapes were determined. Validations were performed using 3D solid and acoustic elements in a direct coupling finite element format. The modal results and AM ratios were in agreement with the experimental results. Convenient application and high efficiency are basic requirements for an engineering application. Therefore, an empirical formula was established for the first-order FSI natural frequency to enable rapid estimation, thereby satisfying this requirement.

The application of portable aluminum‐air batteries (AABs) in extreme environments is an inevitable demand for future development. Aqueous electrolyte freezing is a major challenge for low‐temperature operations. Conventionally, enlightened by the organic system in metal ion batteries, blindly increasing the concentration is regarded as an efficient technique to reduce the freezing point (FP). However, the underlying contradiction between the adjusting mechanism of the FP and OH− transportation is ignored. Herein, the aqueous alkali solution of CsOH is researched as a prototype to disclose the intrinsic conductive behavior and related solvent structure evolution. Different from these inorganic electrolyte systems, the concept of a critical anti‐freezing concentration (CFC) is proposed based on a specific temperature. The relationship between hydrogen bond reconstruction and de‐solvation behavior is analyzed. A high conductivity is obtained at −30 °C, which is also a recorded value in an intrinsic aqueous AAB. The homogenous dissolution of the Al anode is also observed. As a general rule, the CFC concept is also applied in both the KOH and NaOH systems. [ABSTRACT FROM AUTHOR]

Low-frequency noise has a long wavelength, decays very slowly, and is extremely penetrating. Traditional marine acoustic insulation materials have difficulty achieving effective control of this low-frequency noise. In this paper, a series-parallel arrangement structure of a low-frequency metamaterial is designed, which mainly comprises convoluted channels and Helmholtz cavities in series and a sandwich arrangement of multiple cells (as opposed to the traditional parallel arrangement). We use a numerical method to establish an acoustic-solid coupling model for the metamaterial, consider the influence of thermal and viscous losses on its sound absorption performance, and investigate the sound absorption characteristics and mechanisms of the single-cell and multicell structures. The metamaterial designed in this paper shows an average absorption coefficient of 0.97 in the range of 130–145 Hz. An experimental model was prepared by 3D printing, and the intended sound absorption effect was experimentally verified. [ABSTRACT FROM AUTHOR]

Thermal imidization restricts the application of fluorinated polyimide, but the low temperature imidization could cause a certain impact on its performance. PAA was synthesized with fluorinated monomer 4, 4'-(six fluoro isopropenyl) phthalic anhydride (6FDA) and 4 4'-, two amino -2, 2'- three fluorine biphenyl (TFMB), and then through gradient heating by 80 ℃/1 h, 110 ℃/2 h, 150 ℃/2 h, 200 ℃/1 h, 250 ℃/30 min, 300 ℃/30 min and adding acetic anhydride /pyridine mixture into PAA, two kinds of PI films were prepared and characterized. The test results show that PI films prepared by chemical imidization has better transparency, solubility and mechanical properties, while the PI films prepared by thermal imidization has smaller relative dielectric constant, and higher initial decomposition temperature and higher imidization rate.