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This study focuses on applying artificial intelligence techniques to virtually simulate the vibration characteristics of the resonance box of a college symphony orchestra to improve the understanding and optimization of the acoustic performance of the instrument. The study uses the finite element method and digital waveguide technology to simulate and analyze the vibration characteristics of the stringed resonating musical instrument, which is realized by the vibration equation of an ideal string and the principle of digital waveguide algorithm. The experimental results show that the applied simulation technique can effectively simulate the vibration characteristics of the resonance box of the musical instrument, such as the ideal string vibration and the cavity coupling effect. In addition, the study involves the mathematical expressions of forced vibration and resonance and the effects of various materials on the modal frequencies of the resonance box. The application of artificial intelligence technology in studying acoustic characteristics of musical instruments significantly improves the accuracy and efficiency of simulation. It provides essential theoretical support for the design and production of musical instruments.

High myopia is a common ocular genetic disease in the world. The study sought to investigate the effect of the Insulin-like growth factor-1 (IGF-1) and Matrix metalloproteinase-9 (MMP-9) genes polymorphisms on high myopia in a Han population of China. This study recruited 216 unrelated Han Chinese subjects, including 103 cases with high myopia and 113 controls. Four tagging single nucleotide polymorphisms (SNPs) of IGF-1 and MMP-9 genes were genotyped using the Sequenom MassARRAY method. The chi-square test showed that the family history was significantly correlated with myopia. The SNP genotypes were all in Hardy–Weinberg equilibrium (P > 0.05). Among the four SNPs, there were statistically significant differences in the genotype and allele frequencies of rs2236416 between the groups (P = 0.024). The significant associations of rs2236416 between cases and controls also appeared after Bonferroni multiple correction (P = 0.024). Then, there were significant differences in the genotypes dominant model and codominant model of rs2236416 between groups (P = 0.007 and P = 0.004, respectively). rs5742632 showed a significant difference between the cases and the controls in the recessive model (P = 0.037). Our findings indicated that rs2236416 of MMP-9 was associated with myopia in the population. The result suggested MMP-9 gene locus may play a role in myopia.

More and more special automation equipment had been developed with progress of technology. All kinds of nonstandard equipment were applied to the specific occasion. A vision guided intelligent handing system in the paper was specially designed for carrying the inner ring and outer ring of railway-bearing from material handcart to the testing line. Robot, visual positioning, pneumatic clamping jaw, servo motor and PLC were integrated into this handing system. The visual system was led to take pictures for the inner and outer rings by robot, and transfer the location data of rings to the PLC, the brain of the whole system. The PLC controlled robot and pneumatic clamping jaw finish the handing process through accurate calculation.

Three-dimensional global hybrid simulations are performed to explore how the interplanetary magnetic field (IMF), the Martian crustal fields, and planetary pickup ions affect the twisting of the Martian magnetotail. The results agree with previous studies that the crustal magnetic fields cause the Martian magnetotail to twist counterclockwise or clockwise depending on the sign of the IMF Y -component in the Mars solar orbital coordinates. However, the twist is more pronounced when the crustal fields are on the nightside, contradicting the early explanation that the crustal fields affect the twist through dayside magnetic reconnection between the crustal fields and the draped IMF. Additionally, planetary pickup ions also contribute to the twist because their mass loading slows down the plasma flow and leads to the bending of the magnetic field lines in the magnetotail. It is demonstrated that the twist inside Mars' shadow in the near magnetotail region (at X = −1.5 R M, where R M is Mars' radius) is mainly attributable to the crustal fields, while the influence of planetary pickup ions starts to dominate outside Mars' shadow and in regions further away from Mars. [ABSTRACT FROM AUTHOR]

Proton cyclotron waves (PCWs) upstream of Mars are thought to be associated with the instabilities of pickup ions. The instabilities of pickup ions of ring distributions have larger maximum growth rates compared with beam distributions. However, observations revealed a notably‐reduced occurrence rate of PCWs for pickup ions of ring distributions. Linear instability analysis and a corresponding two‐dimensional particle‐in‐cell (PIC) simulation are performed to investigate the instabilities of pickup ion ring distributions upstream of Mars. Linear instability analysis indicates that a pickup ion ring distribution is unstable to the ion cyclotron, ion Bernstein, and mirror instabilities. The corresponding PIC simulation confirms the linear analysis results and further demonstrates that the pickup ions are scattered toward an isotropic shell distribution by the waves excited. Interestingly, the saturation energy of the waves is much lower than that driven by a corresponding pickup ion beam distribution, and mirror waves eventually dominate the system. Plain Language Summary: Without the shielding of a global intrinsic magnetic field, the Martian exosphere interacts directly with the solar wind. Pickup ions are generated when neutrals in the exosphere are ionized and "picked up" by the solar wind. The instabilities driven by these pickup ions lead to the generation of proton cyclotron waves upstream of Mars. Despite that linear analysis indicates higher maximum growth rates for pickup ion ring distributions compared with beam distributions, observations show that the excitation of observable waves upstream of Mars is relatively rare with pickup ion ring distributions. The present study carries out linear instability analysis for pickup ions with a ring distribution. The results reveal that the ion cyclotron, ion Bernstein, and mirror instabilities are unstable. The subsequent particle‐in‐cell simulation validates the linear theory prediction and illustrates the scattering of the pickup ions by the enhanced waves. Interestingly, although the ion cyclotron instability has the largest maximum growth rate, it eventually diminishes and transforms into Alfvén waves. Consequently, the simulation is dominated by mirror waves in the late stage. More importantly, the wave saturation energy for pickup ion ring distributions is much lower than for beam distributions. Key Points: A pickup ion ring distribution is unstable to the ion cyclotron, ion Bernstein, and mirror instabilitiesThe instability saturation level is lower for a ring distribution than a corresponding beam distributionThe mirror waves have the maximum power spectrum eventually in the simulation [ABSTRACT FROM AUTHOR]

Spectral tunable technology has to meet the requirements of strong robustness and wide spectral range. We propose a method for the transmission and manipulation of infrared topological photonic crystal valley states based on tunable refractive index method that exhibits broad-spectrum and multi-band characteristics, along with a tunable emission angle. With this structure, different rotational directions of vortex light sources can independently excite the K valley and K′ valley within the frequency band ranging from 75.64 THz to 99.61 THz. At frequencies from 142.60 THz to 171.12 THz, it is possible to simultaneously excite both the K valley and K′ valley. The dual refractive index tunable design allows for the adjustment of the emission angle at a fixed frequency, enabling control over the independent excitation of either a single K valley or K′ valley, as well as their simultaneous excitation. This capability has significant implications for photonic computation and tunable filtering, offering enhanced operational flexibility and expanded functionality for future optical communications and integrated optical circuits. [ABSTRACT FROM AUTHOR]

The deprotonation–reprotonation sequence introduces additional cyclization branches in terpene biosynthesis. However, the underlying mechanism remains poorly understood. In this study, we employed a combined approach of molecular dynamics (MD) simulations and site-directed mutagenesis on astellifadiene synthase EvAS from Emericella variecolor to investigate the role of a protonated S85 residue. This residue acts as a catalytic acid, previously unreported, that facilitates the reprotonation step in astellifadiene biosynthesis. Mutating S85 led to the production of a new tricyclic sesterterpene. [ABSTRACT FROM AUTHOR]

Terpene synthases (TPSs) play pivotal roles in generating diverse terpenoids through complex cyclization pathways. Protein engineering of TPSs offers a crucial approach to expanding terpene diversity. However, significant potential remains untapped due to limited understanding of the structure‐function relationships of TPSs. In this investigation, using a joint approach of molecular dynamics simulations‐assisted engineering and site‐directed mutagenesis, we manipulated the aromatic residue cluster (ARC) of a bifunctional terpene synthase (BFTPS), Pestalotiopsis fici nigtetraene synthase (PfNS). This led to the discovery of previously unreported catalytic functions yielding different cyclization patterns of sesterterpenes. Specifically, a quadruple variant (F89A/Y113F/W193L/T194W) completely altered PfNS′s function, converting it from producing the bicyclic sesterterpene nigtetraene to the tricyclic ophiobolin F. Additionally, analysis of catalytic profiles by double, triple, and quadruple variants demonstrated that the ARC functions as a switch, unprecedently redirecting the production of 5/11 bicyclic (Type B) sesterterpenes to 5/15 bicyclic (Type A) ones. Molecular dynamics simulations and theozyme calculations further elucidated that, in addition to cation‐π interactions, C−H⋅⋅⋅π interactions also play a key role in the cyclization patterns. This study offers a feasible strategy in protein engineering of TPSs for various industrial applications. [ABSTRACT FROM AUTHOR]