Search Results (1,886)

Objective: The P-POSSUM scale is widely used in predicting perioperative morbidity and mortality. Evidence on the performance of P-POSSUM in predicting outcomes after cytoreductive surgery (CRS) for ovarian cancer (OC) is limited. In this study, we assess how well P-POSSUM predicts morbidity in OC CRS and explore whether incorporating additional clinical variables can enhance its predictive accuracy. We retrospectively collected data on consecutive patients undergoing OC CRS within a tertiary gynaecologic oncology network. The collected information included demographic characteristics, P-POSSUM morbidity and mortality scores, Edmonton Frail Scale (EFS) scores, preoperative serum albumin levels, and observed 30-day postoperative morbidity and mortality, classified using the Clavien–Dindo (CD) scale. The predictive performance of P-POSSUM was evaluated using receiver operating characteristic (ROC) curves to calculate sensitivity and specificity. A stepwise regression analysis was then applied to identify additional variables that could improve model performance, incorporating preoperative covariates. The final model incorporated parameters chosen through bootstrap investigation of the model variability (stepAIC). Predicted versus observed morbidity was calibrated and performance compared between P-POSSUM and the final model. Results: Of 161 sequential OC patients, 95 (59%) underwent primary, 45 (28%) interval, and 21 (13%) delayed CRS. The mean age was 66.4 (95%CI: 60–75) and duration of surgery was 223 mins (95%CI: 142–279). Sixty-five (40.3%) patients had ≥1 postoperative complication. Two deaths were reported. Among the observed complications, 4 patients (6.1%) experienced CD4, 10 patients (15.3%) CD3, 38 patients (58.5%) CD2, and 11 patients (16.9%) CD1 events. The mean P-POSSUM-predicted morbidity and mortality were 59.5% (95%CI: 56.7–62.3%) and 5.86% (95%CI: 5.02–6.70%), respectively. The area under the curve (AUC) for P-POSSUM in predicting morbidity and mortality was 0.539 (p = 0.401) and 0.569 (p = 0.137), respectively. Given the small number of deaths, no robust conclusions regarding mortality are possible. EFS and BMI emerged as significant predictors of observed morbidity using a stepwise-model selection process. The AIC of this final model was 211.44. Our final model of PPOSSUM + EFS + BMI had AUC = 0.6551 (Delong’s Z = 1.8845, p-value = 0.05949). Conclusions: The P-POSSUM scale shows poor performance for predicting morbidity in OC CRS. New validated and accurate model(s) are necessary for predicting surgical morbidity. Our proposed model incorporates additional variables to improve P-POSSUM’s performance. This requires further development and validation. Full article

Let p be a prime and ${\mathbb{F}}_p$ a finite field of order p. This paper investigates cyclic codes over the ring $R_{p^2,u}={\mathbb{Z}}_{p^2}+u{\mathbb{Z}}_{p^2}$ of order $p^4$, where the nilpotent element u satisfies $u^2=0$ and $pu\ne 0.$ The condition $u^2=0$ with $pu\ne 0$ is crucial, as it creates a nontrivial interaction between the components of the ring, allowing the construction of new codes with enhanced structural and distance properties. We provide explicit generating sets for cyclic codes over $R_{p^2,u}$ and study fundamental parameters such as their rank and Hamming distance. In the case $\gcd (n,p)=1$, we show that cyclic codes can be generated by just two polynomials, which allows a complete determination of their rank and minimal Hamming distance distributions. Furthermore, using the Gray map from $R_{p^2,u}$ to ${\mathbb{F}}_p^4$, we construct all but one of the ternary optimal codes of length 12 as images of cyclic codes over $R_{3^2,u}$, with computations verified using the Magma system. Full article

14CrMoR steel, possessing excellent low-temperature impact toughness and corrosion resistance, is an important material for core equipment in the coal chemical industry. In this paper, 14CrMoR steel was subjected to single-pass compression tests at deformation temperatures ranging from 900 to 1150 °C and strain rates of 0.1, 1, 5, and 10 s⁻¹. The hot deformation behavior and constitutive relationship were investigated. The strain rate sensitivity factor m, power dissipation coefficient η, and instability parameter ξ were calculated, respectively. A power dissipation map was plotted, and a hot processing map was established. The results showed that the stress of 14CrMoR steel increased with the decrease in deformation temperature and the increase in strain rate. Dynamic recrystallization was likely to occur at high deformation temperatures and low strain rates. When the strain rate was 10 s⁻¹, in the temperature range of 900–950 °C, the power dissipation rate was the lowest. With the increase in temperature, the power dissipation rate rose, and the maximum power dissipation rate was reached in the temperature range of 1100–1150 °C. The research on the hot deformation behavior of 14CrMoR steel has important guiding significance for the design and optimization of the process. Full article

In this paper, we investigate the behavior of solutions to a nonlinear system of rational difference equations of order two, defined by $x_{n+1}={\displaystyle \frac{x_n{y}_{n-1}}{y_n(a+b{x}_n{y}_{n-1})}},y_{n+1}={\displaystyle \frac{y_n{z}_{n-1}}{z_n(c+d{y}_n{z}_{n-1})}},z_{n+1}={\displaystyle \frac{z_n{x}_{n-1}}{x_n(e+f{z}_n{x}_{n-1})}},$ where n denotes a nonzero integer; the parameters $a,b,c,d,e,f$ are real constants; and the initial conditions $x_{-1},x_0,y_{-1},y_0,z_{-1},z_0$ are nonzero real numbers. By applying a suitable variable transformation, we reduce the original coupled system to three independent rational difference equations. This allows for separate analysis using established methods for second-order nonlinear recurrence relations. We derive explicit solutions and examine the qualitative behavior, including boundedness and periodicity, under different conditions. Our findings contribute to the theory of rational difference equations and offer insights for higher-order systems in applied sciences. Full article

In this paper, a finite-time three-axis stabilization controller for an underactuated rigid spacecraft is proposed based on well-designed hierarchical terminal sliding mode surfaces to handle the insufficiency of control effort and disturbances. Firstly, the attitude kinematic of an underactuated rigid spacecraft is parameterized by the w-z representation and the dynamic model with only two orthogonal torque inputs are presented. Secondly, based on the terminal sliding mode theory, a three-hierarchized sliding surface is established. A finite-time stable control law is derived by the Filippov equivalence theorem and the principle of sliding mode control. The finite-time stability is proved by the Lyapunov theory. Finally, the high performance of the proposed control approach is verified through numerical simulations and comparisons with state-of-the-art studies. Full article

You Only Look Once (YOLO) is a convolutional neural network-based object detection algorithm widely used in real-time vision applications. However, its high computational demand leads to significant power consumption and cost when deployed in graphics processing units. Field-programmable gate arrays offer a low-power alternative. However, their efficient implementation requires architecture-level optimization tailored to limited device resources. This study presents an optimized YOLOv2 accelerator for the Zynq-7000 system-on-chip (SoC). The design employs 16-bit integer quantization, a filter reuse structure, an input feature map reuse scheme using a line buffer, and tiling parameter optimization for the convolution and max pooling layers to maximize resource efficiency. In addition, a stall-based control mechanism is introduced to prevent structural hazards in the pipeline. The proposed accelerator was implemented on the Zynq-7000 SoC board, and a system-level evaluation confirmed a negligible accuracy drop of only 0.2% compared with the 32-bit floating-point baseline. Compared with previous YOLO accelerators on the same SoC, the design achieved up to 26% and 15% reductions in flip-flop and digital signal processor usage, respectively. This result demonstrates feasible deployment on XC7Z020 with DSP 57.27% and FF 16.55% utilization. Full article

Francis turbines operating in sediment-laden flows experience efficiency loss and reduced service life due to abrasive wear. To enhance wear resistance, this study optimized the turbine at Mupo Hydropower Station in Sichuan Province. Using the Plackett–Burman design, three runner parameters were identified as most influential: blade number, inlet setting angle, and outlet setting angle. A central composite design based on response surface methodology was then applied to these factors. Multiple regression models linking the parameters to turbine head, efficiency, and wear rate were established, revealing a trade-off between hydraulic performance and wear resistance. Multi-objective optimization, a method that simultaneously addresses and balances multiple competing goals, was performed to minimize wear rate while maintaining the original head. The optimal parameter combination was obtained as follows: blade number Z₃ = 17, inlet setting angle ${\alpha }_1$ = 65°, and outlet setting angle ${\alpha }_2$ = 22°. Numerical results demonstrate a 32.3% reduction in runner wear under these parameters, with the head requirement satisfied, confirming a significant improvement in overall turbine performance. Full article

Crop–livestock integration is widely adopted as a strategy for recovering degraded pastures. In this system, intercropping crops such as sorghum with tropical grasses enables the harvest of sorghum for silage while simultaneously establishing a new pasture. However, interspecific competition for resources can limit sorghum development and yield, potentially compromise the fermentation process and reduce the nutritional quality of the silage. Therefore, this study aimed to evaluate the agronomic performance, fermentative characteristics, and chemical–bromatological composition of silages produced from different biomass sorghum-grass intercropping systems. The experiment was conducted in a randomized block design with a 3 × 2 factorial arrangement: three cropping systems [sorghum monoculture, sorghum intercropped with Marandu grass (S + M), and sorghum intercropped with Zuri grass (S + Z)] and two sorghum row spacings (45 and 90 cm). The S + Z intercropping system with 90 cm row spacing showed the highest total dry matter yield (16.42 t/ha). It also presented better fermentative parameters, such as pH (4.02) and lactic acid (5.31%DM) and superior nutritional quality, with lower fiber content and higher concentrations of NFC (24.79%DM), TDN (59.75%DM), and digestibility. It is concluded that intercropping biomass sorghum with Zuri grass at 90 cm spacing is the most promising strategy for producing high-quality silage. Full article

Saline-alkali stress seriously affects the growth and development of crops. Sorghum bicolor (L.), a C4 plant, is an important cereal crop in the world, and its growth and geographical distribution are limited by alkali conditions. In this study, sorghum genotypes with different alkaline resistance (alkaline-sensitive Z1 and alkaline-tolerant Z14) were used as experimental materials to explore the effects of alkali on sorghum seedlings. RNA-seq technology was used to examine the differentially expressed genes (DEGs) in alkali-tolerant Z14 to reveal the molecular mechanism of sorghum response to alkali stress. The results showed that plant height, root length, and biomass of both cultivars decreased with time under 80 mM NaHCO₃ treatment, but Z14 showed better water retention abilities. The photosynthetic fluorescence parameters and chlorophyll content also decreased, but the Fv/Fm, ETH, ΦPSII, and chlorophyll content of Z14 were significantly higher than those of Z1. The level of reactive oxygen species (ROS) increased in both sorghum varieties under alkali stress, while the enzyme activities of SOD, POD, CAT, and APX were also significantly increased, especially in Z14, resulting in lower ROS compared with Z1. Transcriptome analysis revealed around 6000 DEGs in Z14 sorghum seedlings under alkali stress, among which 267 DEGs were expressed in all comparison groups. KEGG pathways were enriched in the MAPK signaling pathway, plant hormone signal transduction, and RNA transport. bHLHs, ERFs, NACs, MYBs, and other transcription factor families are actively involved in the response to alkali stress. A large number of genes involved in photosynthesis and the antioxidant system were found to be significantly activated under alkali stress. In the stress signal transduction cascades, Ca²⁺ signal transduction pathway-related genes were activated, about 23 PP2Cs in ABA signaling were upregulated, and multiple MAPK and other kinase-related genes were triggered by alkali stress. These findings will help decipher the response mechanism of sorghum to alkali stress and improve its alkali tolerance. Full article

Background: Electrochemical impedance spectroscopy (EIS) is indispensable for disentangling charge-transfer, capacitive, and diffusive phenomena, yet reproducible parameter estimation and objective model selection remain unsettled. Methods: We derive closed-form impedances and analytical Jacobians for seven equivalent-circuit models (Randles, constant-phase element (CPE), and Warburg impedance (ZW) variants), enforce physical bounds, and fit synthetic spectra with 2.5% and 5.0% Gaussian noise using hybrid optimization (Differential Evolution (DE) → Levenberg–Marquardt (LM)). Uncertainty is quantified via non-parametric bootstrap; parsimony is assessed with root-mean-square error (RMSE), Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC); physical consistency is checked by Kramers–Kronig (KK) diagnostics. Results: Solution resistance ($R_s$) and charge-transfer resistance ($R_{ct}$) are consistently identifiable across noise levels. CPE parameters $(Q,n)$ and diffusion amplitude $\left(\sigma \right)$ exhibit expected collinearity unless the frequency window excites both processes. Randles suffices for ideal interfaces; Randles+CPE lowers AIC when non-ideality and/or higher noise dominate; adding Warburg reproduces the ${45}^{\circ }$ tail and improves likelihood when diffusion is present. The $(R_{ct}+Z_W)\Vert \mathrm{CPE}$ architecture offers the best trade-off when heterogeneity and diffusion coexist. Conclusions: The framework unifies analytical derivations, hybrid optimization, and rigorous statistics to deliver traceable, reproducible EIS analysis and clear applicability domains, reducing subjective model choice. All code, data, and settings are released to enable exact reproduction. Full article

Background: After a warm-up and before the start of sports competition, athletes often take a break. During this break, the effects of the warm-up (e.g., capillary vasodilation) may diminish. The aim of this study was to compare cardiorespiratory responses during high-intensity physical exercise, either preceded or not preceded by post-warm-up breathing, using an additional respiratory dead space volume mask (ARDSv). Methods: The study included 20 trained cyclists. Each participant completed two 3 min tests at an intensity of 110% of their maximal power, determined during a progressive test. A standardised warm-up preceded each 3 min test. Following the warm-up, there was an 8 min passive rest period. During this break, participants either breathed using ARDSv or breathed normally (non-ARDSv). The volume of the ARDSv mask was 1000 mL. Cardiorespiratory parameters were measured during the tests, including mean: oxygen uptake (VO₂av), respiratory exchange ratio (RERav), respiratory rate (RRav), tidal volume (TVav), stroke volume (SVav), and rating of perceived exertion (RPE). Results: VO₂peak was higher in participants breathing using ARDSv compared to non-ARDSv (4.22 ± 0.40 [CI: 4.03–4.41] vs. 3.98 ± 0.42 [CI: 3.79–4.18]; p = 0.002; t = 3.56; d = 0.585). Additionally, RERav (1.08 ± 0.06 [CI: 1.06–1.11] vs. 1.13 ± 0.06 [CI: 1.11–1.16]; p = 0.008; t = 2.96; d = 0.833) and RPE (18.0 ± 1.7 [CI: 17.3–18.8] vs. 18.9 ± 1.1 [CI: 18.4–19.4]; p = 0.009; Z = 2.61; r = 0.583) were lower in participants breathing using ARDSv compared to non-ARDSv. Conclusions: Breathing using ARDSv between warm-up and high-intensity exercise increases oxygen uptake and reduces perceived exertion, likely through peripheral mechanisms. These effects suggest practical applications in competitive sports and provide directions for further mechanistic research. Full article

(1) Background: Low back pain (LBP) is the most prevalent cause of disability worldwide, yet current assessment relies mainly on subjective questionnaires, underscoring the need for objective and interpretable biomarkers. Bioelectrical impedance parameter (BIP), quantified by resistance (R), impedance magnitude (Z), and phase angle (PA), reflects tissue hydration and cellular integrity and may provide physiological correlates of pain; (2) Methods: This cross-sectional study used lumbar BIP and demographic characteristics from 83 participants (38 with lumbar BIP and 45 normal controls). We applied Extreme Gradient Boosting (XGBoost), a regularized tree-based machine learning (ML) algorithm, with stratified five-fold cross-validation. Model interpretability was ensured using SHapley Additive exPlanations (SHAP), which provide global importance rankings and local feature attributions. Outcomes included classification of LBP versus healthy status and regression-based prediction of pain scales: the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Roland–Morris Disability Questionnaire (RMDQ); (3) Results: The classifier achieved high discrimination (ROC–AUC = 0.996 ± 0.009, sensitivity = 0.950 ± 0.068, specificity = 0.977 ± 0.049). Pain prediction showed best performance for VAS (R² = 0.70 ± 0.14; mean absolute error = 1.23 ± 0.27), with weaker performance for ODI and RMDQ; (4) Conclusions: These findings suggest that explainable ML models applied to BIP could discriminate between LBP and healthy groups and could estimate pain intensity, providing an objective complement to subjective assessments. Full article

In industrial bamboo machining, the suboptimal selection of cutting parameters leads to elevated cutting power and increased surface roughness. To enhance the machinability of bamboo, a multi-objective optimization of cutting parameters was conducted using orthogonal experimental methods, with special focus on the influences of fiber direction, feed per tooth, and cutting speed on cutting power and surface roughness. The main findings of this study are summarized as follows: feed per tooth exhibited the greatest effect on cutting power, followed by cutting speed and fiber direction. In contrast, fiber direction exerted the most substantial influence on surface roughness, with feed per tooth and cutting speed ranking second and third, respectively. Furthermore, the optimal milling parameters for minimizing both cutting power and surface roughness were identified as a fiber direction of 0°, a feed per tooth of 0.2 mm/z, and a cutting speed of 400 m/min. Therefore, the obtained optimal parameters are recommended for industrial bamboo machining to achieve reduced cutting power and improved surface quality. Full article

Background/Objectives: Ocular wavefront aberrations are clinically relevant for optimizing vision correction and predicting surgical outcomes. This study aimed to establish normative reference ranges for a Korean population by quantifying wavefront aberrations using a Hartmann–Shack wavefront sensor and Zernike coefficients, and to assess correlations with age, sex, and spherical equivalent (SE). Methods: Wavefront aberrations were measured in 98 Koreans (196 eyes) using a Hartmann–Shack aberrometer without cycloplegia. Five repeated measurements per eye at a 6 mm pupil size were averaged. Parameters included Zernike coefficients (Z3–Z20), higher-order aberration (HOA) root mean square (RMS, Z6–Z20), and total RMS (Z3–Z20). Associations with age, sex, and SE were assessed using univariable and multivariable linear mixed-effects models. Second-order polynomial regression assessed nonlinear relationships. Interocular symmetry was evaluated using mirror-symmetry-adjusted Spearman’s correlation and intraclass correlation coefficients (ICCs). Results: Vertical coma (Z7, 0.208 ± 0.174 μm) and spherical aberration (Z12, 0.200 ± 0.161 μm) were the largest contributors to HOA RMS. Mean HOA RMS and total RMS were 0.51 ± 0.21 μm and 3.03 ± 2.51 μm, respectively. HOA RMS increased with age (β = 0.003 μm/year, p = 0.010), whereas total RMS decreased with SE (β = −0.678 μm/D, p < 0.001). Most Zernike coefficients showed positive interocular correlations, with ICCs of 0.75 for total RMS and 0.64 for HOA RMS. Conclusions: In normal Korean eyes, HOAs increased with age and exhibited significant interocular symmetry. Vertical coma and spherical aberration were predominant components. While the pattern was similar to that in Western populations, the absolute values were greater. These normative values may aid future wavefront-guided refractive surgery and presbyopia correction procedures. Full article

In this paper, a UAV target tracking method with 6G integrated sensing and communication (ISAC) is proposed to address the surveillance requirements for unmanned aerial vehicle (UAV) targets in the context of the rapid development of low-altitude economy. Firstly, a target tracking system model for UAVs is established based on the ISAC base station transceiver architecture. Then, an unscented Kalman filter (UKF) target tracking framework is designed to tackle the occlusion effect during UAV navigation. Specifically, the measurement position information of the UAV is obtained through a spatial rotation-based parameter estimation method. Subsequently, occlusion is detected by analyzing the Line-of-Sight (LoS) visibility between the UAV and the base station. On this basis, the problem of short-term and long-term trajectory loss under occlusion is solved by integrating cubic interpolation with a constant velocity (CV) model, which enables real-time UAV trajectory tracking. Finally, simulation results demonstrate that: (1) under no occlusion, the average estimation errors of the X/Y/Z axes are 0.82 m, 0.79 m, and 0.68 m, respectively; (2) under short-term occlusion, the average errors of the X/Y/Z axes are 1.25 m, 2.18 m, and 1.05 m, with a convergence time of 1 s after LoS recovery; (3) under long-term occlusion, the average errors of the X/Y/Z axes are 2.87 m, 3.79 m, and 1.85 m, with a convergence time of 5 s after LoS recovery; (4) the velocity estimation error can quickly converge to within 0.2 m/s after re-acquiring observations. The proposed method exhibits small trajectory and velocity estimation errors in different occlusion scenarios, effectively meeting the requirements for UAV target tracking. Full article