Deep Ocean Technology (Poland)

The cross-boundary communication between unmanned aerial vehicles (UAVs) and autonomous underwater vehicles (AUVs) constitutes a pivotal component in achieving full coverage of the space-air-ground-sea integrated network of 6G. In such hybrid networks, it is imperative to intelligently plan the trajectory of UAVs by exploiting the deep reinforcement learning (DRL) technique and direct optical wireless communication (OWC) technology to ensure timely data collection. However, the traditional DRL technique suffers from issues such as sparse rewards and low sampling efficiency, which leads to a decrease in the freshness of data. To address these issues, in this paper, we investigate the trajectory planning problem for swarms of UAVs conducting data collection with age of information awareness. Leveraging the prior knowledge of large language models (LLMs) and multi-agent reinforcement learning technique, we propose a novel multi-UAV maritime data collection scheme. Firstly, we extract the prior knowledge strategies of LLMs in the form of expert trajectories through structured prompts. Then, initial strategy models are rapidly generated for UAVs through multi-agent behavior cloning method, which reduce ineffective exploration and accelerates learning. Finally, the MATD3 algorithm is used to fine-tune these strategy models, enhancing their policy learning capability in sparse reward environments. We also conduct simulations to validate the effectiveness of the proposed algorithms.

With the continuous deepening of ocean exploration and the growth of emergency rescue needs, the hydroacoustic transducer, as an important component of sonar, has become more and more demanding. To improve the reception performance of the piezoelectric transducer, we developed a high-frequency, high-sensitivity planar piezoelectric transducer. A variant 1-3-2 type piezoelectric material is used to improve the effective electromechanical coupling coefficient, the upper surface of the material is covered with a brass plate to amplify the reception stress, and two variant 1-3-2 type piezoelectric materials with different dimensional parameters are arranged vertically to expand the bandwidth. We investigated the material properties and determined the material dimensions actually used to fabricate a planar hydroacoustic transducer utilizing electromechanical equivalent circuit analysis methods and finite element simulations. A prototype planar hydroacoustic transducer was fabricated and tested for resonant frequency, receiver sensitivity, bandwidth, and horizontal directivity then. The results show that the transducer’s resonant frequency is about 218.7kHz, the maximum receiving sensitivity is -178.7dB, the 3dB loss receiving bandwidth is about 45kHz, and the horizontal directivity is about 17°. The test results all indicate that the developed hydroacoustic transducer has great potential for application in marine exploration and underwater emergency rescue.

Magnesium was reported to be necessary for bone formation. Previous study indicated nanofiltrated deep ocean water (DOW) rich in magnesium. This study investigated the potential mechanisms of DOW in ameliorating osteoporosis. Briefly, female Sprague-Dawley rat was ovariectomized and fed with 0.35, 0.7, or 1.4ml/kg of DOW daily for 8weeks. In the results, DOW increased bone density, decreased trabecular bone loss, and decreased bone adiposity. DOW improved bone mass by examining structure in micro-computed tomography. About 0.35 and 0.7ml/kg of DOW can increase protein expression of runt-related transcription factor 2 (RUNX2), an essential transcription factor for regulating osteoblast differentiation, by 9.4% or 12.9%. In human osteoblast, DOW increased the levels of osteocalcin, RUNX2, and alkaline phosphatase; all the proteins can regulate osteoblast differentiation. Considering the results of in vivo and in vitro study, DOW can ameliorate ovareictomy-caused osteoporosis via regulating the osteoblast differentiation, thereby, maintenance of bone structure. PRACTICAL APPLICATIONS: In addition to calcium, magnesium is essential to promoting the deposition of calcium in bones and regulating its transport; it may also slow the progression of osteoporosis. Nanofiltrated DOW contains abundant magnesium along with several microelements and peptides. In this study, a product was developed for decelerating osteoporosis by using an estrogen depletion model. DOW regulates osteoblast differentiation and thus prevents osteoporosis. This finding provides an alternative healthy source of bone supplements. In addition to tablets or capsules, aqueous supplements can be produced to achieve osteoporosis prevention. This finding is beneficial to the health-care industry for developing sustainable supplements.

Matrix metalloproteinases (MMPs) are crucial extracellular matrices degrading enzymes that take important roles in metastasis of cancer progression as well as other significant conditions such as oxidative stress and hepatic fibrosis. Natural products are on the rise for their potential to provide remarkable health benefits. In this context, halophytes have been of interest in the nutraceutical field with reported instances of isolation of bioactive compounds. In this study, Limonium tetragonum, an edible halophyte, was studied for its ability to inhibit MMP-2 and -9 using HT1080 fibrosarcoma cells. Results showed that L. tetragonum extract was able to inhibit the enzymatic activity and mRNA expression of MMP-2 and -9 according to gelatin zymography and RT-PCR assays, respectively, but it was not able to significantly change the MMP pathway related factors such as tissue inhibitors of metalloproteinases. Also, Mitogen-activated protein kinases pathway-related protein levels and their phosphorylation were assayed. While the phosphorylated p38 levels were decreased, extracellular signal-regulated kinase and c-Jun N-terminal kinase were not affected by L. tetragonum treatment. In conclusion, it was suggested that L. tetragonum contains substances acting as MMP inhibitors on enzymatic activity rather than intracellular pathway intervention, which could be useful for further utilization of L. tetragonum as a source for anti-MMP agents.

Underwater gliders carried acoustic velocity meters can realize ocean profile observations of the acoustic velocity for long duration and large scale. This paper mainly studies the kinematics and hydrodynamics of the Slocum underwater glider carrying a acoustic velocity meter MINOSX with length 565mm and diameter 76mm. Thus, theory reference for optimal design parameters of the underwater glider is proposed. By establishing the kinematic equations and giving some related parameters, variations with time of the steady-state gliding velocity, pitch angle, gliding path and attack angle are simulated by using Matlab software; The simulation calculations of the hydro-drag and lift are completed by using Fluent software. Finally, this paper summarizes the dynamic characteristics in steady state of the underwater glider in longitudinal plane.

The submersible buoy system is an important tool in the profile observation of marine environment. According to the lumped mass based method, the dynamic modeling of the submersible buoy system is established, then the dynamic analysis is carried out. The dynamic model is solved and analyzed by using the software MATLAB. The result provides theoretical reference for its structural design and numerical computation of the submersible buoy system.