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Abstract Background The current study was conducted aimed atexploring the effects of staged rehabilitation training on the levels of inflammatory factors and red blood cell distribution in patients who underwent cardiac valve replacement. Methods A total of 140 patients who underwent cardiac valve replacement at The First Hospital of Hebei Medical University between April 2021 and November 2022 were included in this study. During the postoperative rehabilitation phase, the patients were randomly assigned to either the control group or the experimental group. The experimental group received staged rehabilitation training (n = 70), while the control group received conventional care and rehabilitation suggestions without specialized staged rehabilitation training (n = 70). Informed consent was obtained from all patients prior to theirinclusion in the study. Clinical data of the patients were collected andanalyzed. RDW was measured using an automated blood cell analyzer on postoperative day 1, 14, and 28. Levels ofTNF-α, IL-6 and CRP were measured using ELISA. Quality of life was evaluated usingthe WHOQOL-BREF questionnaire. The effects of postoperative rehabilitation were assessed using the 6MWD test. The occurrence of adverse events in the postoperative periodwas alsoanalyzed. Results There were no significant differences in the general characteristics of the two groups of patients (P > 0.05). On the first day after surgery, no significant differences were seen in RDW between the two groups (P > 0.05). However, on the 14th and 28th day after surgery, the experimental group exhibited a significant reduction in RDW compared to the control group (P 0.05). However, on the 14th and the 28th after surgery, the experimental group showed evidently lower levels of TNF-α, IL-6 and CRP compared to the control group (P 0.05). Conclusion Staged rehabilitation training exerteda positive effect on the levels of inflammatory factors and red blood cell distribution in patients following cardiac valve replacement. This type of rehabilitation training facilitated the patient’s recovery process by reducing the inflammatory response and improving the condition of red blood cells. Additionally, it enhanced the quality of life and rehabilitation outcomes for patients.

The variation in aerodynamic parameters during the process of a variable sweepback hybrid aerial underwater vehicle (HAUV) affects flight stability. During the air–water trans-media locomotion, there are medium mutations and solid–liquid gas coupling phenomena, resulting in the complex dynamic process of HAUV. To ensure stable control during the trans-media process of a variable sweepback vehicle, this study proposes a neural-network-based adaptive dynamic surface control method for aircraft flight-path angle. This method aims to establish an effective control model for the entire process of air to media transition, in response to the characteristics of uncertainty and external disturbances in the process of variable backsweeping in the air and media transition. By utilizing the multibody dynamics method, the dynamic equations for variable-swept vehicles are established and transformed into a rigorous feedback system with model uncertainty. The adaptive dynamic surface method in this paper introduces a first-order filter, which overcomes the “differential explosion” problem in traditional backstepping control design through differential filtering; the unknown parameters present in the model are estimated online through adaptive laws, and the uncertain parts of the system are overcome through nonlinear damping items. By analyzing Lyapunov stability, the semi-global stability of the required closed-loop system can be obtained, and adjusting the controller parameters can make the tracking error infinitely small. Numerical simulations are conducted to illustrate the tracking control of flight-path angles for different plunge-diving angle rates and strategy of ingress. The results show that HAUV with variable-swept configuration with different strategy has a great effect on the stability of plunge-diving locomotion; the designed controller can effectively track the target trajectory and has a certain degree of robustness and adaptability.

In this paper, the problems of system design, dynamic modeling, and trajectory tracking control of coaxial hybrid aerial underwater vehicles (HAUVs) with time-varying model parameters and composite marine environment disturbances are investigated. It is clear that a stable transition between different media remains a challenge in the practical implementation of amphibious tasks. For HAUVs, accurate dynamic modeling to describe complex dynamic variations during vehicle takeoff from underwater to air is a huge challenge. Meanwhile, due to the rapid changes in model parameters and the external environment, vehicles are likely to fall into the sea during the cross-domain process. An integrated continuous dynamic model considering hydrodynamic changes is established by introducing a linear switching coefficient during the process of trans-medium motion. A nonsingular fast terminal sliding-mode control (NFTSMC) algorithm combined with adaptive technology is used to design the position and attitude of the controller. With no previous knowledge of external interferences and lumped uncertainties of the HAUV, the adaptive NFTSMC (ANFTSMC) algorithm achieves the control objectives; at the same time, the inherent chattering problems of sliding mode control (SMC) are weakened. The finite-time stability of the global system is proven strictly using a series of mathematical derivations based on Lyapunov theory. The effect of the controller applied is analyzed through a series of simulations with representative working conditions. The results show that the proposed ANFTSMC can realize a “seamless” air–water trans-medium process, which proves the superiority and robustness of the proposed control algorithm.

A quasi-isotropic dielectric resonator antenna (DRA) is proposed under the 5.8 GHz industrial, scientific, and medical (ISM) standard. The antenna consists of a hollow cylinder and and a coaxial probe which feeds electricity. By digging a large hole in the cylindrical dielectric resonator, the HEM11δ mode and TM10 mode of the oor are excited, the two modes are orthogonal, and the radiation characteristics are equivalent to orthogonal magnetic dipoles and electric dipoles, so as to achieve quasi- isotropic radiation characteristics. The large hole can also reserve space for other electronic components for Bluetooth devices with small space, such as capsule endoscope, mobile phone, and Bluetooth headset. The characteristics of the antenna are simulated and analyzed by HFSS, and the optimized antenna structure parameters are obtained. The antenna is made for experimental testing. The measured results demonstrate that the antenna exhibits a good -10 dB-impedance bandwidth at 5.38-5.68 GHz and has the characteristics of miniaturization, quasi-isotropy, and high gain. [ABSTRACT FROM AUTHOR]

Mobile learning (M-learning) is currently popular. Although M-learning has a positive effect on the interest, attitude, initiative, and learning of learners, it comes with the negative effect of distraction. Exploring the factors that influence M-learning concentration have become a popular research subject. Environment (quiet and noisy) and posture (sitting, standing, and moving) are two typical factors that directly influence the concentration of mobile learners. This study focuses on the influence of environment and posture on concentration in M-learning. A total of 120 college students were randomly divided into two environment groups, namely, the quiet and noisy environments. The two groups were subjected to M-learning experiments by adopting sitting, standing, and moving postures. This study shows that (1) interaction effects on Mlearning concentration existed between environment and posture and a quiet environment and a sitting posture enable learners to concentrate better; and (2) no interaction effects on M-learning achievement existed between environment and posture, while environment and posture alone had a significant effect on learning achievement. This study presents several implications of the M-learning practice, deficiencies of the research, and the direction of future studies in this field. [ABSTRACT FROM AUTHOR]

A conformal quasi-isotropic dielectric resonator antenna (DRA) is first investigated for wireless capsule endoscope (WCE) application under the 5.8-GHz industrial, scientific, and medical (ISM) standard. The probe-fed hemispherical DRA (HDRA) is studied to match the shape of the spherical dome end, and the characteristic mode analysis (CMA) tool is applied to analyze the resonant modes of the proposed antenna to reveal the intrinsic behavior of the dielectric resonator. It is found that the quasi-isotropic radiation pattern can be achieved by combining HDRA's TE111 sinφ mode which radiates like a magnetic dipole and a small ground plane's TM10 mode that radiates like an electric dipole. In order to reach the requirement of 5.8 GHz in ISM, a ceramic hemispherical dielectric resonator with dielectric constant of 21.984 is investigated. The radius of the hemisphere is set to 5.35mm. In free space, the measurement results show that the proposed antenna achieves 3.25% bandwidth, 86% maximum efficiency, and 7.2 dB gain deviation. The antenna is also measured in pork to approximate human body environment. The measurement results demonstrate that the antenna achieves 3.20% bandwidth, 8.15% maximum efficiency, and 9.0 dB gain deviation. Accordingly, the proposed antenna is suitable for WCE application at 5.8 GHz ISM standard. [ABSTRACT FROM AUTHOR]

A dual-passband frequency selective surface (FSS) is designed in this paper. Two passbands are 2-3.4GHz and 5.5-6.8GHz, respectively. It is used as a spatial filter to improve the radiation and scattering performance of an antenna. The structure is combined with two layers. One is metal, and the other is intermediate medium. The requirements of wide-band, polarization-independent, wide incidence angle and miniaturized FSS with a thickness of only 0.0085λ are achieved by parameter optimization. When the FSS is used to the proposed microstrip antenna, the relative bandwidth is increased by 31.4% and 50%, and the peak gain is increased by 2.53 dB and 1.86 dB at 5.8 GHz and 6.4GHz, respectively. Meanwhile, the maximum RCS reduction of the microstrip antenna is 16 dB. On the other hand, the FSS is able to be applied to a dipole antenna to improve the transmission coefficient and phase. Simulation and measurement results of the transmission coefficient and phase of the antenna are almost the same. [ABSTRACT FROM AUTHOR]