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ObjectivesSignificant increase in tacrolimus exposure was observed during co-administration with voriconazole, and no population pharmacokinetic model exists for tacrolimus in renal transplant recipients receiving voriconazole. To achieve target tacrolimus concentrations, an optimal dosage regimen is required. This study aims to develop individualized dosing parameters through population pharmacokinetic analysis and simulate tacrolimus concentrations under different dosage regimens.MethodsWe conducted a retrospective study of renal transplant recipients who were hospitalized at the Second Xiangya Hospital of Central South University between January 2016 and March 2021. Subsequently, pharmacokinetic analysis and Monte Carlo simulation were employed for further analysis.ResultsNineteen eligible patients receiving tacrolimus and voriconazole co-therapy were included in the study. We collected 167 blood samples and developed a one-compartment model with first-order absorption and elimination to describe the pharmacokinetic properties of tacrolimus. The final typical values for tacrolimus elimination rate constant (Ka), apparent volume of distribution (V/F), and apparent oral clearance (CL/F) were 8.39 h−1, 2690 L, and 42.87 L/h, respectively. Key covariates in the final model included voriconazole concentration and serum creatinine. Patients with higher voriconazole concentration had lower tacrolimus CL/F and V/F. In addition, higher serum creatinine levels were associated with lower tacrolimus CL/F.ConclusionOur findings suggest that clinicians can predict tacrolimus concentration and estimate optimal tacrolimus dosage based on voriconazole concentration and serum creatinine. The effect of voriconazole concentration on tacrolimus concentration was more significant than serum creatinine. These findings may inform clinical decision-making in the management of tacrolimus and voriconazole therapy in solid organ transplant recipients.

Autonomous underwater vehicle (AUV) equipped with ducted propellers exhibit increased maneuverability. However, ducting also influences the AUV's dynamic characteristics. Accordingly, it is crucial to analyze the effect that ducted propellers exert on an AUV's hydrodynamic performance. This paper utilizes computational fluid dynamics (CFD) to study this impact. Firstly, two AUV models with identical geometry except for the presence of ducted propellers were constructed using 3D software. Subsequently, two sets of overlapping grids for the CFD hydrodynamic analysis were created, each for one of the AUVs. Hydrodynamic coefficients for both models were obtained by calculating their translational and rotational motions, and differences between these coefficients were analyzed to evaluate the ducted propellers' effect. The computational results reveal that ducted propellers augment the inertial hydrodynamic forces in surge motion while reducing those in sway, heaven, pitch, and yaw motions. In addition, the presence of ducted propellers heightens the viscous hydrodynamic forces during translational motion and diminishes them during rotational motion. The ducted propeller further impacts the AUV's streamlined shape, thereby altering the AUV's inertial and viscous hydrodynamic characteristics. Therefore, when designing AUV with ducted propellers, it is critical to consider the effect of ducting on the AUV.

Dynamic target tracking is a crucial technique for autonomous underwater vehicles (AUV), enabling key operations such as target detection and reconnaissance. Standard approaches for tracking maneuvering targets often involve the interacting multiple model (IMM) algorithm which integrates the constant velocity (CV) model and the coordinated turn (CT) model. However, these models traditionally utilize fixed transition probabilities and turn rates based on prior information, potentially leading to imprecise state estimations. In response to this, the paper introduces an adaptive parallel IMM (APIMM) based on current adaptive IMM algorithms. This method adaptively adjusts transition probabilities and pairs with the unscented Kalman filter (UKF) algorithm for state prediction of maneuvering targets in a 3D underwater environment. The enhanced algorithm chooses from a model set that encompasses the CV model, the 3D fixed center constant speed and turning rate model (CSCTR) with an adaptive turn rate, and the current statistical (CS) model. Simulation outcomes have demonstrated that this algorithm utilizes posterior information more effectively, possesses an accelerated model switching speed, and improves the prediction accuracy of the underwater dynamic target's state in three-dimensional space by approximately 15%.

Concerning the challenges of limited operational capabilities of autonomous underwater vehicles and the impaired passability caused by the externally mounted propellers on the existing chained multi-body underwater vehicles, this paper presents an overall design scheme for a multi-joint unmanned underwater vehicle composed of a functional carrier and a basic carrier. Initially, the structural arrangements of the functional carrier and basic carrier are introduced. Subsequently, a comprehensive exploration of the key technological principles incorporated in the scheme, such as jet manipulation, vector propulsion, folding antennas, among others is conducted. Lastly, a physical prototype of the basic carrier for the multi-joint unmanned underwater vehicle is developed, followed by successive trials in lake and sea environments. In the directional variable depth navigation tests, the depth error was no more than ±0.1 m, and the heading error was not exceeding ±1°. These experiment results validate the sailing capabilities of the basic carrier of the multi-joint unmanned underwater vehicle, thereby confirming the feasibility of the proposed design scheme for a multi-joint unmanned underwater vehicle in this paper.

为探究城市居民低碳出行意向与行为差异的原因和异质性，基于大中小城市、老中青群体1 263名居民的低碳出行问卷调查数据，采用双变量Probit模型和组间平均边际效应（AME），分析了城市和群体间低碳出行意向与行为一致性的影响因素及群体差异。结果表明：有低碳出行意向与行为的居民比例仅为12.6%，有低碳出行意向而未向行为转变的居民占55.3%，意向与行为不一致的现象在一线城市和青年群体中尤为明显。从平均边际效应的结果看，有无私家车是导致一线、二线城市居民和中、青年群体低碳出行意向与行为不一致的关键因素。环境意识和主观规范对老年群体的低碳出行意向与行为一致性具有更显著的积极影响。研究所揭示的影响不同群体低碳出行意向与行为一致性的关键因素，可为低碳政策的异质化实施提供理论参考。

Purpose: To compare the survival outcomes of postoperative adjuvant aspirin with surgery alone in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) and portal vein tumor thrombus (PVTT). Methods: From June 2013 to July 2015, an open-label, randomized controlled study was conducted in patients with resectable HBV-related HCC and PVTT. Patients were randomly assigned to undergo surgical resection and postoperative adjuvant aspirin (n = 40) or hepatectomy alone (n = 40). The primary end point was overall survival (OS). The secondary end points were time to recurrence of primary tumor (t-TTR) and time to recurrence of PVTT (p-TTR). The expression levels of COX1 and COX2 in surgical specimens of the aspirin group were correlated with patients’ survival. Results: The median OS were 16.2 and 13.4 months for the adjuvant aspirin and surgery alone groups, respectively. The median t-TTR were 5.3 and 3.2 months for the adjuvant aspirin and surgery alone groups, respectively. There was no significant difference in the OS and t-TTR between the two groups of patients (P = 0.078 and 0.336, respectively). The median p-TTR were 12.0 months and 5.4 months for the adjuvant aspirin group and the surgery alone group, respectively. Patients in the adjuvant aspirin group had markedly longer p-TTR (P = 0.001). Increased expressions of COX1 or COX2 in tumor tissues denoted better prognosis for patients receiving adjuvant aspirin. Conclusion: For patients with resectable HBV-related HCC and PVTT, postoperative adjuvant aspirin significantly prolonged time to recurrence of PVTT than surgery alone. Expression of COX1 or COX2 may predict survival in these patients.